UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

White clover seed production in British Columbia 1978

You don't seem to have a PDF reader installed, try download the pdf

Item Metadata

Download

Media
UBC_1979_A6_7 H89.pdf [ 15.25MB ]
Metadata
JSON: 1.0075132.json
JSON-LD: 1.0075132+ld.json
RDF/XML (Pretty): 1.0075132.xml
RDF/JSON: 1.0075132+rdf.json
Turtle: 1.0075132+rdf-turtle.txt
N-Triples: 1.0075132+rdf-ntriples.txt
Citation
1.0075132.ris

Full Text

WHITE CLOVER SEED PRODUCTION IN BRITISH COLUMBIA by DAVID MORTON HUXLEY B. S c , U n i v e r s i t y of B r i t i s h Columbia, 1970 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF Master of Science i n The Fa c u l t y of Graduate Studies Department of Plant Science (F a c u l t y of A g r i c u l t u r a l Sciences) The U n i v e r s i t y of B r i t i s h Columbia We accept t h i s t h e s i s as conforming to the r e q u i r e d standard. THE UNIVERSITY OF BRITISH COLUMBIA November 1978 (c) David Morton Huxley, 1978. In presenting t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of the requirements f o r an advanced degree at the U n i v e r s i t y o f B r i t i s h Columbia, I agree that the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r reference and study. I f u r t h e r agree t h a t permission f o r extensive copying o f t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the Head of my Department or by h i s r e p r e s e n t a t i v e s . I t i s understood that copying or p u b l i c a t i o n of t h i s t h e s i s f o r f i n a n c i a l g ain s h a l l not be allowed without my w r i t t e n permission. David M. Huxley Department of Plant Science The U n i v e r s i t y of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 Date i i ABSTRACT In the Creston v a l l e y i n southeastern B.C., intermediate white c l o v e r i s grown f o r seed and i s a u s e f u l crop i n farm f i e l d r o t a t i o n s . For se v e r a l years seed y i e l d s have been d e c l i n i n g , and de s p i t e good p r i c e s and markets, hectarage to white c l o v e r i s d e c l i n i n g . In 1976, work was i n i t i a t e d to determine some of the f a c t o r s respons- i b l e f o r the d e c l i n e i n seed y i e l d and hectarage. At the same time, an ex p l o r a t o r y study of the genetic v a r i a t i o n i n the seed stocks of the v a l l e y was i n s t i t u t e d i n the hope that a Creston s t r a i n might be c h a r a c t e r i z e d or s e l e c t e d . In 1977, i n the Creston v a l l e y , a s e r i e s of r e p l i c a t e d p l o t s i n s i x f i e l d s , r e p r e s e n t a t i v e of the edaphic, c l i m a t i c and management regimes, were e s t a b l i s h e d to measure seed and forage y i e l d s and losses from m u l t i p l e sources. At the U n i v e r s i t y of B.C., four hundred i n d i v i d u a l p l a n t s represent- a t i v e of twenty sources, i n c l u d i n g some Creston sources, and encompassing s u b s t a n t i a l genetic d i v e r s i t y , were e s t a b l i s h e d from seed i n r e p l i c a t e d uniform n u r s e r i e s . In an adjacent nursery one hundred and eighty Creston clones were e s t a b l i s h e d . Observation and measurement of a number of char- a c t e r s were taken on a l l p l a n t s s e v e r a l times during the growing season. Average cl e a n seed y i e l d s on the Creston experimental p l o t s ranged from 468-972 kgs. per hectare (418-868 l b s per a c r e ) . Farm y i e l d s of clea n seed, by c o n t r a s t , ranged from 262-491 kgs per hectare (240 to 450 lb s per a c r e ) . I t was estimated that of the l o s s i n seed threshed (dock- age) , but not cleaned, 3-10% was i n s e c t damaged; l o s s a t t r i b u t a b l e to farm ha r v e s t i n g procedures was estimated to reach 50%. Losses i n the developing crop are d i f f i c u l t to assess q u a n t i t a t i v e l y but appeared to be very s e r i o u s . To o f f s e t these l o s s e s , i n recent years, i i i producers have been reducing the length of white c l o v e r l e y and are now i n most cases o b t a i n i n g one seed crop only i n the year a f t e r establishment; t h i s p r a c t i c e , i f c a r r i e d on without counter s e l e c t i o n , might r e s u l t i n a b i e n n i a l h a b i t . Three species of weevil appeared to be the most serious p e s t s , v i z . the c l o v e r root c u r c u l i o (Sitona h i s p i d u l a Fab.), and the c l o v e r seed weevil (Miccotrogus p i c i r o s t r i s (F)) and the l e s s e r c l o v e r l e a f weevil (Hypera n i g r i r o s t r i s Fab.). The p o p u l a t i o n peaks of the a d u l t s apparently occur at d i f f e r e n t times i n the season. C u r r e n t l y only one a e r i a l a p p l i c a - t i o n of malathion i s a p p l i e d i n June to c o n t r o l the c l o v e r seed w e e v i l . Almost a l l r o o t s examined bore signs of l a r v a l feeding, doubtless due to the c l o v e r root c u r c u l i o ; root nodules, abundant i n s p r i n g , diminished r a p i d l y as the season progressed. Measurements of n i t r o g e n f i x a t i o n , using the acetylene r e d u c t i o n technique and the K j e l d a h l N-determination, were incomplete. Flower frequency and development, flower c o l o u r , l e a f area, p e t i o l e l ength, l e a f markings, p l a n t height and weight, and p r u s s i c a c i d l e v e l s were some of the characters measured and observed on the i n d i v i d u a l p l a n t s , e s t a b l i s h e d i n the U.B.C. n u r s e r i e s from Creston and other sources. Not unexpectedly, the Creston stocks possessed a measure of d i s t i n c t i o n from most other stocks o f intermediate white c l o v e r ; nonetheless, there appeared to be ample v a r i a b i l i t y i n the Creston stocks w i t h i n which to s e l e c t s t r a i n s to meet at l e a s t two needs of the r e g i o n - v i z . a) p l a n t s u s e f u l i n the r e v e g e t a t i o n of ranges and of unstable s o i l s , and b) p l a n t s w e l l adapted to the a r a b l e long l e y pastures of the humid and sub-humid areas. i v TABLE OF CONTENTS INTRODUCTION REVIEW OF RELEVANT LITERATURE 2.1 General "biology of white c l o v e r 2.1.1 Nomenclature 2.1.2 Agronomic races 2.1.3 S t r a i n s 2.1.4 Seed 2.1.5 A e r i a l development 2.1.6 Reproductive s t r u c t u r e s 2.1.7 Root systems 2.2 B i o l o g i c a l n i t r o g e n f i x a t i o n 2.3 Marker genetics 2.3.1 I n t r o d u c t i o n 2.3.2 Cyanogenesis 2.3.3 Leaf markings 2.4 Seed production 2.4.1 General b i o l o g y and management 2.4.2 Pests of white c l o v e r seed crops 2.h.3 Diseases of white c l o v e r seed crops DESCRIPTION OF STUDY AREAS 3.1.1 Creston 3.1.2 F i e l d management 3.1.3 S o i l s e r i e s by f i e l d s OBSERVATIONS AND EXPERIMENTS A. For Creston Based*Studies 4.1 Sampling f o r Insects 4.1.1 Sweeps 4.1.1.1 M a t e r i a l s and methods 4.1.1.2 Observations and r e s u l t s 4.1.1.3 D i s c u s s i o n V PAGE NO. 4.1.2 S t i c k y t r a p s 39 it.1.2.1 M a t e r i a l s and methods 39 4.1.2.2 Observations and r e s u l t s 40 4.1.2.3 D i s c u s s i o n 44 k.1.3 P i t f a l l t r a p s 4 4 4.1.3.1 M a t e r i a l s and methods 4 4 4.1.3.2 Observations and r e s u l t s 4 4 4.1.3.3 D i s c u s s i o n 4 8 4.1.4 S o i l i n s e c t sampling 4 8 4.1.4.1 M a t e r i a l s and methods 4 8 4.1.4.2 Observations and methods 4 9 4.1.4.3 D i s c u s s i o n 51 4.2 S o i l Sampling f o r F e r t i l i t y 53 4.2.1 M a t e r i a l s and methods 53 4.2.2 Observations and r e s u l t s 53 4.2.3 D i s c u s s i o n 53 4.3 Phytomass Sampling 54 4.3.1 For dry matter y i e l d s on 30-5-77 54 4.3.1.1 M a t e r i a l s and methods 54 4.3.1.2 Observations and r e s u l t s 54 4.3.1.3 D i s c u s s i o n 54 4.3.2 For dry matter y i e l d s on 5-8-77 54 4.3.2.1 M a t e r i a l s and methods 54 4.3.2.2 Observations and r e s u l t s 54 4.3.̂ 2.3 D i s c u s s i o n 58 4.3.3 For seed and i n f l o r e s c e n c e y i e l d s on 5-8-77 58 4.3.3.1 M a t e r i a l s and methods 58 4.3.3.2 Observations and r e s u l t s 58 4.3.3.3 D i s c u s s i o n 58 4.3.4 I n d i v i d u a l head examinations 62 4.3.4.1 M a t e r i a l s and methods 62 4.3.4.2 Observations and r e s u l t s 62 4.3.4.3 Di s c u s s i o n 6 2 4.3.5 Leaf a r e a , p e t i o l e l e n g t h and peduncle l e n g t h 62 4.3.5.1 M a t e r i a l s and methods 62 4.3.5.2 Observations and r e s u l t s 65 4.3.5-3 D i s c u s s i o n 65 4.3.6 Swath sampling f o r standing crop and seed weight 70 4.3.6.1 M a t e r i a l s and methods 70 4.3.6.2 Observations and r e s u l t s 70 4.3.6.3 D i s c u s s i o n 70 4.4 Sampling f o r N i t r o g e n - f i x i n g A c t i v i t y 74 4.4.1 M a t e r i a l s and methods 74 4.4.2 Observations and r e s u l t s 74 4.4.3 D i s c u s s i o n 75 v i PAGE WO. 4.5 Mowing T r i a l s 75 4.5.1 M a t e r i a l s and methods 75 4.5.2 Observations and r e s u l t s 75 4.5.3 D i s c u s s i o n 75 4.6 Coated Seed T r i a l 77 4.6.1 M a t e r i a l s and methods 77 4.6.2 Observations and r e s u l t s 77 4.7 F e r t i l i z e r T r i a l s 77 4.7.1 M a t e r i a l s and methods 77 4.7.2 Observations and r e s u l t s 78 4.8 Sampling f o r Cyanogenesis i n Creston White Clover 78 4.8.1 M a t e r i a l s and methods 78 4.8.2 Observations and r e s u l t s 78 4.8.3 D i s c u s s i o n 78 B. Studies undertaken at the U n i v e r s i t y of B.C. 79 4.9 S t r a i n E v a l u a t i o n using Groups of S i n g l e P l a n t s 79 4.9.1 General comments on experimental design 79 and l a y o u t 4.9.2 V a r i a t i o n i n f l o w e r i n g by date 79 4.9.2.1 M a t e r i a l s and methods 79 4.9.2.2 Observations and r e s u l t s 81 4.9.2.3 D i s c u s s i o n 81 4.9.3 V a r i a t i o n i n l e a f area 87 4.9.3.1 M a t e r i a l s and methods 87 4.9.3.2 Observations and r e s u l t s . 88 4.9.3.3 D i s c u s s i o n 88 4.9.4' V a r i a t i o n i n p e t i o l e l ength 94 4.9.4.1' M a t e r i a l s and methods 94 '4.9.4.2 Observations'and r e s u l t s 94 4\9.4.3 D i s c u s s i o n 94 4.9.5 V a r i a t i o n i n l e a f shape and markings 99 4.9.5.1 M a t e r i a l s and methods 99 4.9.5.2 Observations and r e s u l t s 99 4.9.5.3 D i s c u s s i o n 104 4.9.6 V a r i a t i o n i n p l a n t height 104 4.9.6.1 M a t e r i a l s and methods 104 4.9.6.2 Observations and r e s u l t s 104 4.9.6.3 D i s c u s s i o n 104 4.9.7 V a r i a t i o n i n cyanogenesis 109 4.9.7.1 M a t e r i a l s and methods 109 4.9.7.2 Observations and r e s u l t s 109 4.9.7.3 D i s c u s s i o n 109 v i i PAGE NO. 4.9.8 V a r i a t i o n i n p l a n t weight 110 4.9.8.1 M a t e r i a l s and methods 110 4.9.8.2 Observations and r e s u l t s 110 4.9.8.3 D i s c u s s i o n 110 4.10 V a r i a t i o n w i t h i n and between Clones 110 4.10.1 Comment on t r i a l l a y out 110 4.10.2 V a r i a t i o n i n l e a f area 115 4.10.2.1 M a t e r i a l s and methods 115 4.10.2.2 Observations and r e s u l t s 115 4.10.3 V a r i a t i o n i n p e t i o l e l e n g t h 121 4.10.3.1 M a t e r i a l s and methods 121 4.10.3.2 Observations and r e s u l t s 121 4.10.4 V a r i a t i o n i n p l a n t weight 121 4.10.4.1 M a t e r i a l s and methods 121 4.10.4.2 Observations and r e s u l t s 121 4.10.5 V a r i a t i o n i n p l a n t height 127 4.10.5-1 M a t e r i a l s and methods 127 4.10.5.2 Observations and r e s u l t s 127 4.10.6 V a r i a t i o n i n l e a f markings 129 4.10.6.1 M a t e r i a l s and methods 129 4.10.6.2 Observations and r e s u l t s 129 4.11 Coated Clover Seed T r i a l 129 4.11.1 M a t e r i a l s and methods 129 4.11.2 Observations and r e s u l t s 129 4.11.3 D i s c u s s i o n 131 4.12 Acetylene Reduction T r i a l s 131 4.12.1 M a t e r i a l s and methods 131 4.12.2 Observations and r e s u l t s 131 4.12.3 D i s c u s s i o n 132 5. GENERAL DISCUSSION AND CONCLUSIONS 133 6. LITERATURE CITED 140 7. APPENDIX 151 . v i i i LIST OF TABLES Table Page No. 1.1 L i s t i n g of acreage, average y i e l d , t o t a l y i e l d s , 2 p r i c e per pound and t o t a l value f o r white c l o v e r seed production i n the Creston v a l l e y . 4.1.1 Average number of weevils c o l l e c t e d by sweeping 37 the f o l i a g e at Creston; numbers presented f o r each species by f i e l d and date. 4.1.2 Average number of organisms i n groups c o l l e c t e d 41 by means of s t i c k y t r a p s at Creston; numbers presented f o r each group by f i e l d and date. 4.1.3.1 Organisms c o l l e c t e d by p i t - f a l l t r a p s at Creston; 45 grouping of orders, f a m i l i e s , or genus. 4.1.3.2 Organisms c o l l e c t e d i n p i t - f a l l t r a p s at Creston; 46 dates of c o l l e c t i o n . 4.1.3.3 Average number o f organisms i n groups c o l l e c t e d 47 by means of p i t - f a l l t r a p s at Creston; numbers presented f o r each group by f i e l d and date. 4.1.4.1 An e s t i m a t i o n of root damage by date t o white 50 cl o v e r p l a n t s i n farmers' f i e l d s i n Creston. 4.1.4.2 Nematode counts obtained by e x t r a c t i o n from 52 s o i l - c l o v e r cores from Creston. 4.3.1.1 Top weight samplings i n s i x f i e l d s i n Creston 55 i n May 1977. - 4.3.2.1 Top weight samplings i n s i x f i e l d s i n Creston 55 i n August 1977- . • 4.3.3.1 Seed weights i n s i x f i e l d s i n Creston i n 55 August.1977- 4.3.3.2 Number of heads per u n i t area i n s i x f i e l d s i n 59 Creston, taken i n August 1977- 4.3.3.3 Dependence of seed y i e l d on number of i n f l o r e s - 59 cences per u n i t area. . 4.3.4.1 Number of seeds per head i n s i x f i e l d s i n Creston, 63 August 1977. i x Table Page No 4.3.4.2. Contingency t a b l e f o r insect-damaged seed from 63 i n d i v i d u a l seed heads from Creston f i e l d s i n August 1977. 4.3.5.1 Average l e a f areas i n square centimeters f o r 66 s i x f i e l d s i n Creston, i n J u l y 1977. 4.3.5-2 Average l e a f p e t i o l e lengths i n centimeters 66 f o r s i x f i e l d s i n Creston, i n J u l y 1977. 4.3.5.3 Average ( i n f l o r e s c e n c e ) peduncle lengths i n 66 centimeters f o r s i x f i e l d s i n Creston, i n J u l y 1977. 4.3.5.4 L i n e a r r e g r e s s i o n equations and c o r r e l a t i o n c o e f f i c i e n t s , (Y) f o r l e a f area and p e t i o l e l e n g t h of white c l o v e r i n s i x f i e l d s i n Creston. 4.3.6.1 Estimates of standing crop y i e l d s obtained by 71 sampling swaths i n three Creston f i e l d s , August 1977. 4.3.6.2 Estimates of f i e l d seed y i e l d obtained by sam- 71 p l i n g swaths i n th r e e Creston f i e l d s , August 1977. 4.4.1 Y i e l d o f n i t r o g e n i n kgs/ha f o r standing crops 76 i n s i x Creston f i e l d s . 4.9.1.1 Weight of seed from twenty s t r a i n s of white " 80 c l o v e r p l a n t e d at the U n i v e r s i t y of B.C. 4.9.2.1 Twenty s t r a i n s grown at the U n i v e r s i t y o f B.C. 8 2 ranked according t o average blossom number per p l a n t . 4.9.2.2 R e l a t i o n s h i p of e a r l i n e s s i n f l o w e r i n g t o the 86 number of i n f l o r e s c e n c e s produced. 88 4.9.3.1 Average l e a f area i n square centimeters f o r i n d i v i d u a l p l a n t s i n twenty s t r a i n s , grown i n a uniform nursery at the U n i v e r s i t y of B.C., sampling date: 20-7-77(1). 4.9.3.2 Average l e a f area i n square centimeters f o r 90 i n d i v i d u a l p l a n t s i n twenty s t r a i n s of white c l o v e r , grown i n a uniform nursery at the U n i v e r s i t y Q f B.C. sampling date: : 13-10-77(2). X Table 4.9.3.3 4.9.3.4 4.9.4.1 4.9.4.2 4.9.4.3 4.9.4.4 4.9.5.1 4.9.5.2 4.9.5.3 4.9.5.4 4.9.5.5 4.9.5.6 4.9.6.1 Page No. Contingency t a b l e and Chi-square values f o r 92 average l e a f area f o r twenty s t r a i n s grown at the U n i v e r s i t y of B.C., sampled on the 20-7-77- Contingency t a b l e and Chi-square values f o r 93 average l e a f area f o r twenty s t r a i n s grown at the U n i v e r s i t y of B.C., sampled on the 13-10-77- Average p e t i o l e l e n g t h i n centimeters f o r i n - 95 d i v i d u a l p l a n t s i n twenty s t r a i n s grown i n a u n i - form nursery at the U n i v e r s i t y of B.C., sampling date: 20-7-77. Average p e t i o l e l e n g t h i n centimeters f o r i n d i - 96 v i d u a l p l a n t s i n twenty s t r a i n s grown i n a u n i - form nursery at the U n i v e r s i t y of B.C., sampling date: 13-10-77- R e l a t i o n s h i p of l e a f area t o p e t i o l e l e n g t h ; 97 measurements taken the 20-7-77• R e l a t i o n s h i p s of l e a f area t o p e t i o l e l e n g t h ; 98 measurements taken the 13-10-77- Contingency t a b l e and Chi-square values f o r 100 white c l o v e r l e a f shapes. R a t i o of water marks t o no water marks f o r 101 twenty s t r a i n s of white clover, grown at the U n v i e r s i t y of B.C. • • . • Contingency t a b l e and Chi-square values f o r four 102 cl a s s e s of l e a f markings i n 20 s t r a i n s , of white c l o v e r grown at the U n i v e r s i t y of B.C. ' Rat i o of anthocyanin f l e c k i n g t o no f l e c k i n g 103 f o r twenty s t r a i n s of white c l o v e r grown at the U n i v e r s i t y of B.C. Contingency t a b l e and Chi-square values f o r an- 105 thocyanin f l e c k i n g i n twenty s t r a i n s of white c l o v e r grown at the U n i v e r s i t y of B.C. Contingency t a b l e f o r white c l o v e r l e a f markings 1,06 and anthocyanin l e a f f l e c k i n g on twenty s t r a i n s grown at the U n i v e r s i t y of B.C. Pl a n t height i n centimeters f o r i n d i v i d u a l p l a n t s 107 i n twenty s t r a i n s grown at the U n i v e r i s t y of B.C. x i Table 4.9.8.1 4.9.8.2 4.10.2.1 4.10.2.2 4.10.2.3 4.10.2.4 4.10.3.1 4.10.3.2 4.10.3.3 4.10.4.1 4.10.5.1 'Page No. I n d i v i d u a l p l a n t weights i n gms. f o r twenty 111 s t r a i n s grown at the U n i v e r s i t y of B.C., sam- p l i n g date: 18-8-77(1). I n d i v i d u a l p l a n t weights i n gms. f o r twenty 113 s t r a i n s grown i n a uniform nursery at the U n i v e r s i t y of B.C., sampling date: 19-10-77(2). Area^r e p r e s e n t a t i o n o f i n d i v i d u a l leaves ( i n 116 square centimeters) f o r f i v e s t r a i n s of white c l o v e r at the U n i v e r s i t y of B.C., sampled 20-7-77 (!)•• • Area r e p r e s e n t a t i o n of i n d i v i d u a l leaves ( i n 116 square centimeters) f o r f i v e s t r a i n s of white c l o v e r at the U n i v e r s i t y of B.C., sampled 20-10-77(2). . . . . Mean l e a f area v a r i a b i l i t y w i t h i n clones of f i v e 119 s t r a i n s of white c l o v e r grown i n a uniform nur- sery at the U n i v e r i s t y of B.C.; c o l l e c t i o n date: 20-7-77. Mean l e a f v a r i a b i l i t y w i t h i n clones of f i v e 120 s t r a i n s of white c l o v e r grown i n a uniform nursery at the U n i v e r s i t y of B.C.; c o l l e c t i o n date: 20-10-77- P e t i o l e l e n g t h i n centimeters f o r f i v e s t r a i n s 122 of white c l o v e r grown i n a uniform nursery at the U n i v e r s i t y of B.C., sampled: 20-7-77- P e t i o l e l e n g t h i n centimeters f o r f i v e s t r a i n s 122 of white c l o v e r grown i n a uniform nursery at the U n i v e r s i t y o f B.C., sampled 20-10-77- Lin e a r r e g r e s s i o n equations and c o r r e l a t i o n co- 123 e f f i c i e n t s < f o r white c l o v e r c l o n a l m a t e r i a l f o r two dates grown i n a uniform nursery at the U n i v e r s i t y of B.C. . . . . . • Top.weight i n grams f o r f i v e s t r a i n s of white 124 cl o v e r grown i n a uniform nursery at the Univer- s i t y of B.C. - • . . . , Height i n centimeters f o r f i v e s t r a i n s of white 124 cl o v e r grown i n a uniform nursery at the Univer- s i t y of B.C. , _ . x i i •Table 4.10.4.2 4.10.5.2 4.10.6.1 4.10. 6. 2 Page No. -Mean wight and standard d e v i a t i o n of top growth 126 w i t h i n clones from f i v e s t r a i n s of white c l o v e r grown at the U n i v e r s i t y of B.C. Mean p l a n t height and standard d e v i a t i o n w i t h i n 126 clones from f i v e s t r a i n s of white c l o v e r grown at the U n i v e r s i t y of B.C. Counts of l e a f marks f o r f i v e s t r a i n s of white 130 c l o v e r grown as c l o n a l m a t e r i a l at the Uni- v e r s i t y of B.C. Contingency t a b l e and Chi-square values f o r i n - 130 ver t e d l e a f marks and anthocyanin f l e c k i n g on c l o n a l m a t e r i a l at the U n i v e r s i t y of B.C. x i i i LIST OF ILLUSTRATIONS Figure Page No. .3.1.1 Average temperature, p r e c i p i t a t i o n and f r o s t f r e e 23 p e r i o d at Creston, B.C. 3.1.2 A e r i a l photograph of f i e l d 1. 25 3.1.3 A e r i a l photograph of f i e l d 2. 25 3.1.4 A e r i a l photograph of f i e l d s . 3, 4 and 5. 27 3.1.5 A e r i a l photograph of f i e l d 6. 30 3.2.1 Average temperature, p r e c i p i t a t i o n and f r o s t 35 f r e e p e r i o d at the U n i v e r s i t y of B.C. 4.1.1 Weevils c o l l e c t e d by means o f sweeping the 38 f o l i a g e i n s i x f i e l d s i n the Creston V a l l e y . 4.1.2.1 Assessment of s t i c k y s t r a p s .atICrestan. 42 4.1.2.2 Insects caught on s t i c k y t r a ps i n the Creston 43 v a l l e y i n three f i e l d s . 4.1.3 Graph showing i n s e c t s c o l l e c t e d i n p i t - f a l l t r a p s i n the Creston v a l l e y i n three f i e l d s . 4.3.1.1 The v a r i a t i o n i n weight of top growth i n s i x f i e l d s i n Creston, May 30, 1977(1). 4.3.2.1 The v a r i a t i o n i n weight of top growth i n s i x f i e l d s i n Creston, August 1977 (2). 4.3.3.1 The v a r i a t i o n i n weight of seed from s i x f i e l d s i n Creston, August 1977- 4.3.3.2 The v a r i a t i o n i n the number of heads per u n i t area i n s i x f i e l d s i n Creston, August 1977- 4.3.4.1 The v a r i a t i o n i n number of seeds per head i n s i x f i e l d s i n Creston, August 1977. 4.3.5.1 The v a r i a t i o n i n l e a f area i n s i x f i e l d s i n Creston, J u l y 1977- x i v •Figure Page No, 4.3.5.2 The v a r i a t i o n i n l e a f p e t i o l e l e n g t h f o r s i x 68 f i e l d s i n Creston, J u l y 1911. 4.3.5-3 The v a r i a t i o n i n i n f l o r e s c e n c e peduncle l e n g t h 69 f o r s i x f i e l d s i n the Creston v a l l e y , J u l y 1977- 4.3.6.1 The v a r i a t i o n i n standing crop i n three Creston 72 f i e l d s , August 1977. 4.3.6.2 The v a r i a t i o n i n the weight of seed from three 73 f i e l d s i n Creston, August 1977. 4.9.2.1 The response i n f l o w e r i n g by twenty s t r a i n s of 83 white c l o v e r on the 8-6-77. 4.9.2.2 The response i n f l o w e r i n g by twenty s t r a i n s of 84 white c l o v e r on the 22-6-77. 4.9.2.3- The response i n f l o w e r i n g by twenty s t r a i n s o f " 85 white c l o v e r on the 19-7-77. 4.9.3.1 The v a r i a t i o n i n l e a f area on the 20-7-77 ( l ) 89 f o r twenty s t r a i n s . 4.9.3.2 The v a r i a t i o n i n l e a f area on the 13-10-77 (.2) 91 f o r twenty s t r a i n s . 4.9.6.1 The v a r i a t i o n i n p l a n t height f o r twenty s t r a i n s . 108 4.9-8.1 The v a r i a t i o n i n standing crop weight from the 112 harvest on the 18-8-77 ( l ) of white c l o v e r p l a n t s from twenty s t r a i n s . 4.9.8.2 The v a r i a t i o n i n standing crop weight from harvest 114 on the 19-19-77 (2) of white c l o v e r p l a n t s from twenty s t r a i n s . 4.10.2.1 The v a r i a t i o n i n l e a f area on the 20-7-77 ( l ) ; 117 p l a n t s were grown from c u t t i n g s . 4.10.2.2 The v a r i a t i o n i n l e a f area on the 20-10-77 ( 2 ) ; 118 p l a n t s were grown from c u t t i n g s . 4.10.4.1 The v a r i a t i o n i n top weight f o r p l a n t s grown 125 from c u t t i n g s . 4.10.5-1 The v a r i a t i o n i n height of white c l o v e r p l a n t s 128 grown from c u t t i n g s . XV F i g u r e Page No. 7.1 The Creston v a l l e y i n south-eastern B.C. i s 151 s u i t a b l e f o r the p r o d u c t i o n of h i g h q u a l i t y white c l o v e r seed. 7.2(a) White c l o v e r ranks as one of the world's 151 more important forage p l a n t s . . . i t s a p p l i c a t i o n i n other s i t u a t i o n s i n i n c r e a s i n g (e.g. range r e h a b i l i t a t i o n ) . 7.2(b) Open g r a s s l a n d . 152 7.2(c) F o r e s t e d range. 152 7.3(a) . . . f i f t y percent of the v e g e t a t i v e growth of 153 white c l o v e r , on the Creston f l a t s , takes p l a c e p r i o r t o the end of May. 7.3(b) Creston s t r a i n s , w i t h l e s s f a l l recovery i n top 153 growth, should d i s p l a y a g r e a t e r p e r s i s t e n c e . 7.4(a) The a c t i o n of the c l o v e r root c u r c u l i o l a r v a e 154 leads t o a weakening of the stand, weed i n f e s - t a t i o n . .. .pathogen entry and l o s s of p l a n t p e r s i s t e n c e . 7.4(b) Other organisms such as s l u g s , nematodes and 154 rodents ... t h e i r presence ... observed t o be sp o r a d i c . 7.4(c) ...even weeds of low s t a t u r e such as dandelion. 155 7.4(d) ...and of course t a l l weeds such as p e r e n n i a l 155 sow t h i s t l e . 7.5(a) Volunteer g r a i n from previous years h a r v e s t . 156 7.5(b) ...long stubble remaining a f t e r t h ree previous 156 year's g r a i n h a r v e s t . . . such o b s t r u c t i o n s c o u l d l e a d t o poor bee a c t i v i t y . 7.6 The s t i c k y t r a p s c o n s i s t e d of 9 i n c h by 11 i n c h 157 y e l l o w r a i l r o a d board. 7.7(a) White c l o v e r i n c e r t a i n areas o f d i f f e r e n t s o i l 157 t e x t u r e would f l o w e r prematurely. 7.7(b) Flo w e r i n g i n e a r l y June. 158 x v i Figure 7.7(c) Matured by l a t e June. 7.8 The average number of i n f l o r e s c e n c e s per hec- t a r e was estimated to be 11.5 m i l l i o n . 7.9 Beehives are r o u t i n e l y placed i n each crop of white c l o v e r . 7.10(a) Harvesting g e n e r a l l y commences when 90% of the heads are "brown". 7.10(b) Farmers are experiencing a seed l o s s , w h i l e h a r v e s t i n g , of up to 50%. 7.11(a) I t .is impossible f o r the farmer t o keep the crop longer than on seed harvest. 7.11(b) . C h i s e l ploughed. 7.12 Consequently the t r i a l was abandoned. 7.13 White c l o v e r i s a shor t - l o n g day species and d i f f e r e n t s t r a i n s respond i n f l o w e r i n g t o d i f f e r e n t combinations of temperature and day- len g t h . 7.14(a) Free f l o w e r i n g s t r a i n s are important f o r seed production. 7.14(b) The p e t a l s are white but are occasi o n a l y pink. 7.15(a) L o u i s i a n a . s t r a i n s stood out by t h e i r c o n s i s t e n t presence of the i n v e r t e d "V" l e a f mark. 7.15(b) P l a n t s w i t h no l e a f markings were i n the m i n o r i t y xvdi ACKNOWLEDGEMENTS A p p r e c i a t i o n i s extended to my graduate committee: Dr. V.C. Rune'ckles (Chairman), Department of P l a n t Science; Dr. V.C. B r i n k , Department of P l a n t Science; Dr. A.J. Renney, Department of P l a n t Science; Dr. R.H. E l l i o t t , Department of P l a n t Science; Dr. C A . Rowles, Department of S o i l Science, arid Mr. J.V. Zacharias, Head, F i e l d Crops Branch, B r i t i s h Columbia Department of A g r i c u l t u r e . Acknowledgement i s a l s o given to Dr. G.W. Eaton, Department of Pl a n t Science, f o r h i s advice on s t a t i s t i c a l a n a l y s i s , and t o Dr. R. Copeman, Department of P l a n t Science, f o r examination of m a t e r i a l f o r pathogens. F i n a n c i a l a i d , g r a t e f u l l y acknowledged, has been provided through the A g r i c u l t u r a l Sciences Research and Development fund. S p e c i a l thanks f o r t h e i r f i e l d support and cooperation i n Creston are to be accorded: Mr. S.S. Dhindsa, F i e l d Crops Branch, B r i t i s h Columbia Department of A g r i c u l t u r e , and Mr. R. France, D i s t r i c t A g r i c u l t u r i s t , B r i t i s h Columbia Department of A g r i c u l t u r e , Creston, B.C. S p e c i a l thanks are a l s o accorded to Dr. F. McElroy, A g r i c u l t u r e Canada Research S t a t i o n , Vancouver, B.C. Tec h n i c a l a s s i s t a n c e , g r a t e f u l l y acknowledged, has been provided by Mr. Ilmars D e r i e s , Senior Technician, Department of P l a n t Science, f o r the c o n s t r u c t i o n of an ethylene a n a l y z e r , f o r help i n the determination of n i t r o g e n and p r e p a r a t i o n of s l i d e s . A l s o Mr. D. Pearce, Senior Technician, and' Mr. D. Armstrong, Technician, Department of P l a n t Science, U n i v e r s i t y of B r i t i s h Columbia, are thanked f o r t h e i r a s s i s t a n c e i n f i e l d and greenhouse. S p e c i a l thanks i s extended to Talisman P r o j e c t s , Vancouver, B.C., f o r the d r a f t i n g of f i g u r e s and graphs. F i n a l l y , I am indebted to my F a c u l t y Supervisor, Dr. V.C. B r i n k , Department of P l a n t Science, f o r suggestion of t h i s t o p i c , f o r h i s keen i n t e r e s t , advice and help i n the l a b o r a t o r y , classroom and f i e l d . 1 1. INTRODUCTION The Creston v a l l e y i n south eastern B r i t i s h Columbia i s s u i t a b l e f o r production of high q u a l i t y c l o v e r seed. Furthermore the v a l l e y has become, during the l a s t few decades, one of the more important areas f o r white c l o v e r seed production i n Canada. The crop has been f o r s e v e r a l decades and s t i l l i s an a t t r a c t i v e and important c o n s t i t u e n t of the cropping systems i n the Creston v a l l e y . W i t h i n recent years, seed y i e l d s have d e c l i n e d i n the f i r s t and subsequent years of production (see Table 1.1). One of the o b j e c t i v e s of t h i s research i s a search f o r the major causes of the seed y i e l d d e c l i n e . Two important f a c t o r s make the l o c a l i n d u s t r y worthy of c l o s e s c r u t i n y and support. F i r s t , white c l o v e r , a leguminous crop with a high p o t e n t i a l f o r the f i x a t i o n of atmospheric n i t r o g e n , f i t s i n w e l l w i t h the a g r i c u l t u r a l cropping systems of the Creston v a l l e y . Second, the B.C. market f o r white c l o v e r seed i s moderately l u c r a t i v e and, i n a d d i t i o n , markets are open i n the United States and overseas. A second o b j e c t i v e of the research was to study the w i t h i n s t r a i n v a r i a b i l i t y w i t h a view to determining the s u i t a b i l i t y o f the Creston white c l o v e r stocks f o r d e s i g n a t i o n as a land s t r a i n . Studies of seed production i n white c l o v e r have not been reported i n Canada, t h e r e f o r e t h i s study i s e x p l o r a t o r y and broad; i t i s hoped that a d d i t i o n a l s t u d i e s w i l l f o l l o w . 2 Table 1.1 Hectarage, average y i e l d , t o t a l y i e l d , p r i c e per kilogram and t o t a l value f o r white c l o v e r seed production i n the Creston v a l l e y . Year Hectares Average y i e l d T o t a l y i e l d P r i c e / k g T o t a l v a l 1966 771 607 kgs/ha 468,566 kg - - 1967 - - - 301,869 kg - - 1968 918 492 kgs/ha 453,597 kg 77* $350,000 1969 891 358 kgs/ha 319,786 kg 90* 290,000 1970 761 448 kgs/ha 341,105 kg 165* 564,000 1971 709 560 kgs/ha 396,897 kg 71* 280,000 1972 640 448 kgs/ha 286,673 kg 99* 284,000 1973 607 280 kgs/ha 170,099 kg 143* 243,750 1974 405 269 kgs/ha 108,863 kg 220* 240,000 1975 324 403 kgs/ha 130,636 kg 198* 259,000 1976 243 314 kgs/ha 76,204 kg 176* 134,000 1977 243 426 kgs/ha 103,420 kg 176* 182,400 3 2. REVIEW OF RELEVANT LITERATURE 2.1 General Biology of White Clover White c l o v e r ranks as one of the world's more important forage p l a n t s . With i t s o r i g i n i n the Mediterranean (Davies 1969) i t now enjoys an almost worldwide d i s t r i b u t i o n (Crowder 1960). V a r i a t i o n s i n gross morphology are everywhere very n o t i c e a b l e ; never- t h e l e s s w i t h i n the genus T r i f o l i u m , a l a r g e genus, white c l o v e r ( T r i f o l i u m repens) i s a w e l l defined species (Chromosome No. 2n = 32). Although the general b i o l o g y of white c l o v e r i s the subject of s e v e r a l e a r l y r e p o r t s , notably a monograph by E r i t h (1924) and a b i b l i o g r a p h y (Imperial Bureaux of Pastures and Forage Crops 1939), i t i s u s e f u l to review some of the s a l i e n t f e a t u r e s . 2.1.1 Nomenclature White c l o v e r i s a Linnaean species and i s u n i v e r s a l l y recognized i n t e c h n i c a l nomenclature as T r i f o l i u m repens L.; other common names are white t r e f o i l ; white honeysuckle; shamrock; bubby-roses; q u i l l e t ( E r i t h 1924); white man's f o o t . 2.1.2 Agronomic Races Three forms of white c l o v e r are important agronomically; the race " s y l v e s t r e " , known as w i l d white c l o v e r i s a small but hardy p l a n t . I t enjoys a r e p u t a t i o n f o r p e r s i s t e n c y i n long-term pastures and h i l l pastures i n Great B r i t a i n and other p a r t s of the world. The race " h o l - landicum", known as "common white" or "white Dutch" ( o r i g i n H o l l a n d ) , does not have the p e r s i s t e n c y of w i l d white c l o v e r but i s a l a r g e r p l a n t i n form and i s sometimes r e f e r r e d to as "in t e r m e d i a t e " white c l o v e r . Place of o r i g i n f o r common white seed stocks has r e s u l t e d i n names such as New 4 Zealand white, Kentish white, L o u i s i a n a white ( H o l l o w e l l 1948). Common white i s s u i t e d to mixed l e y s of short to moderate d u r a t i o n (1-5 y e a r s ) . The race "giganteum", commonly known as " L o d i " or "Ladino" i s s i m i l a r i n almost a l l respects to the above two forms mentioned but has a "gigas" or mammoth form. I t y i e l d s a greater amount o f dry matter than the h o l l a n d - icum race and i s commonly grown f o r hay and short-term pastures. 2.1.3 S t r a i n s As mentioned p r e v i o u s l y white c l o v e r i s g r e a t l y v a r i a b l e i n i t s form and performance. However, i t i s p o s s i b l e to group p l a n t s t h a t have c e r t a i n s a l i e n t features i n common yet are not n e c e s s a r i l y i d e n t i c a l . For conven- ience i t i s customary to a s s i g n the name " s t r a i n " or l e s s commonly " c u l t i v a r " ( v a r i e t y ) (Hawkins 1953 and 1960). Hawkins (1959) l i s t s s e v e r a l i n h e r i t e d measurable c h a r a c t e r i s t i c s of white c l o v e r that are u s e f u l f o r s t r a i n c l a s s i f - i c a t i o n and i d e n t i f i c a t i o n . When assigned a name or number, t h i s t e l l s us the p l a n t ' s o r i g i n , type and s u i t a b i l i t y to c e r t a i n uses (Ware 1925). A case i n point i s the Aberystwyth s t r a i n , S.184 w i l d white c l o v e r . E n g l i s h w i l d white c l o v e r , known f o r i t s p e r s i s t e n c y , i s i n form and behaviour q u i t e v a r i a b l e . However by s e l e c t i o n at the Welsh p l a n t breeding s t a t i o n at Aberystwyth a pedigreed s t r a i n S.184 w i l d white c l o v e r was re l e a s e d . This s t r a i n has a greater degree of u n i f o r m i t y with improved performance (Je n k i n 1943). According to U.S.D.A. re p o r t s (1947) the use of the name White Dutch i s misleading since i t no longer represents any p a r t i c u l a r type. At one time i t represented an intermediate type of white c l o v e r but i s now merely a synonym f o r common white c l o v e r . This i s important, since the use of n a t i o n a l i t y serves to des c r i b e the type of p l a n t r a t h e r than j u s t the country of o r i g i n (Ware 1925, Williams 1945). In Canada i t i s grown and marketed as White Dutch with no guarantee as to i t s o r i g i n , performance or u n i f o r m i t y . 5 Understandably s t r a i n s and v a r i e t i e s o f white c l o v e r perform d i f - f e r e n t l y i n the d i f f e r e n t geographic regions o f Canada. The E n g l i s h w i l d white and the Danish s t r a i n s l a c k p e r s i s t e n c e i n places such as Beaverlodge and Ottawa, yet they enjoy moderate success at Aga s s i z , B.C. White Dutch and New Zealand s t r a i n s perform w e l l at Ottawa, yet p o o r l y at Agassiz (Dominion Department o f A g r i c u l t u r e 1941). E l l i o t and Howe (1977) give the r e l a t i v e hardiness and y i e l d s o f white c l o v e r i n t r o d u c t i o n s as t e s t e d at Beaverlodge. The L o u i s i a n a s t r a i n s showed poor hardiness and seed y i e l d while those s t r a i n s of an o r i g i n from a more temperate r e g i o n d i s p l a y e d increased hardiness and seed y i e l d . 2.1.4 Seed The seed i s small (1000 seeds weighing ca. 0.65 grams) and develops i n a legume (the f r u i t ) where the average number o f seeds i s two to three ( E r i t h 1924). The t e s t a i s yellow i n the m a j o r i t y o f cases but i n some cases i s y e l l o w i s h brown or brownish red. The seed coat i n some seeds i s so imperm- eable to moisture that germination i s delayed f o r years. This c o n d i t i o n known as "hard seed" e x i s t s i n about 10% of mechanically harvested seeds i n the common white (United States Department of A g r i c u l t u r e 1915). Robinson (1937) claims t h a t t h i s c o n d i t i o n i s brought about by over-ripeness o f the flower heads a t harvest. Germination i s e p i g e a l . 2.1.5 A e r i a l Development The main stem i s very short and the branches, known as s t o l o n s , are creeping and root at almost every node ( i . e . shoot growth i s indeterminate). I t i s from these nodes al s o that the l e a f and flower buds o r i g i n a t e . The l e a f i s palmate and t r i f o l i a t e being born on a long p e t i o l e . Character- i s t i c d i u r n a l and nocturnal l e a f l e t p o s i t i o n s are probably.-attained by photonastic*' movement ( E r i t h 1924). Brougham (1958) and Denne (1966) 6 suggest that p e t i o l e and l e a f expansion continue f o r almost the e n t i r e l i f e of those p l a n t p a r t s . The average l i f e of a l e a f and i t s p e t i o l e i s approximately f o r t y days a f t e r l e a f expansion. Leaf s i z e and p e t i o l e length do not d i f f e r g r e a t l y under nursery c o n d i t i o n s but may change under b i o t i c ( g r a z i n g ) , edaphic and c l i m a t i c i n f l u e n c e s (Caradus 1977, King 1961). There are p o s i t i v e c o r r e l a t i o n s between p l a n t h e i g h t , weight, r o s e t t e diameter and l e a f area (Barcikowska 1976, Beinhart 1963). Leaves produced e a r l y i n the growing season tend to be l a r g e r than leaves produced l a t e r i n the season (Beinhart 1963). D e f o l i a t i o n i s reported to reduce the s i z e of leaves and the length of p e t i o l e s (Carlson 1966, King et a l . 1978). Observ- ati o n s by Davies (1958) suggest that good l e a f y cuts of white c l o v e r can be taken i n June i n B r i t a i n but subsequent crops are l e s s l e a f y . He a l s o claims that under h i s c o n d i t i o n s , the intermediate White Dutch s t r a i n s give the highest v e g e t a t i v e y i e l d s over a three-year p e r i o d . 2.1.6 Reproductive S t r u c t u r e s The i n f l o r e s c e n c e i s a dense raceme born on a long peduncle that a r i s e s from a l e a f a x i l on a s t o l o n or p r o s t r a t e stem. I t i s made up of 10 to 80 f l o r e t s ; the p e t a l s are white but are o c c a s i o n a l l y pink. The species i s almost always g e n e t i c a l l y s e l f - i n c o m p a t i b l e and c r o s s - f e r t i l i z a t i o n i s necessary (Atwood 1942); the most important p o l l i n a t o r i s the domestic honey bee. Because of cross p o l l i n a t i o n and the s e l f - i n c o m p a t i b i l i t y p l a n t breeding i n white c l o v e r i s d i f f i c u l t . Most s t r a i n s , that are i n use, are the r e s u l t o f the process o f n a t u r a l s e l e c t i o n w i t h only i n c i d e n t a l help by man ( H o l l o w e l l 1948) . As w e l l as sexual propagation, white c l o v e r i s able to maintain i t s e l f a s e x u a l l y by means of s t o l o n s . This ensures d i s p e r s i o n and p e r s i s t e n c e of clones i n l o c a l h a b i t a t s . Work by Harberd (1963) showed that clones are 7 known to have survived longer than s i x t y years and to have spread over an area of twenty yards diameter. 2.1.7 Root Systems White c l o v e r root systems are as v a r i e d as the forms o c c u r r i n g above ground. The w i l d races have a f i b r o u s root system and no tap root on the main stem. On the other hand the Ladino race has a d i s t i n c t tap root but few f i b r o u s roots (Caradus 1977). The common or White Dutch i s intermediate i n that i t has a goodly number of f i b r o u s r o o t s while a d v e n t i t i o u s r o o t s occur at almost every node of the s t o l o n . 2. 2 B i o l o g i c a l Nitrogen F i x a t i o n The v i r t u e s of legumes i n green manuring have been acknowledged by the ancients. However i t was not u n t i l 1890 t h a t H e l l r i e g e l and W i l f a r t h demonstrated c o n c l u s i v e l y that n i t r o g e n f i x a t i o n occurred s y m b i o t i c a l l y i n the root nodules of legumes. Much of the e a r l y l i t e r a t u r e on n i t r o g e n f i x - a t i o n has been reviewed by Wilson (1940). Recently, e s p e c i a l l y w i t h the i n s t i t u t i o n of the I n t e r n a t i o n a l B i o l o g - i c a l Programme, sev e r a l major t e x t s have appeared on the broad subject of b i o l o g i c a l n i t r o g e n f i x a t i o n (Burns and Hardy 1975, Hardy and S i l v e r 1977, Hardy and Gibson 1977, L i e 1971, Nutman 1976, Quispel 1974, Stewart 1966). Nitrogen f i x a t i o n by white c l o v e r occurs as a r e s u l t of a symbiotic (Vincent 1974, 1976) r e l a t i o n s h i p between the p l a n t and b a c t e r i a (Rhizobium t r i f o l i i ) . The b a c t e r i a l R h i z o b i a t h a t i n f e c t white c l o v e r r o o t s are s p e c i f i c to the c l o v e r (genus T r i f o l i u m ) group. Cross i n n o c u l a t i o n by t h i s group of b a c t e r i a on other leguminoid groups such as the a l f a l f a group or the l u p i n groups, w i l l lead to degrees of i n e f f e c t i v e nodules (Wilson 1940). Annual amounts of n i t r o g e n f i x e d by white c l o v e r are s i g n i f i c a n t . Estimates by workers on the amount of n i t r o g e n f i x e d by the white c l o v e r 8 system have been as high as 616 kgs of elemental n i t r o g e n per hectare per annum (Dobson and Beaty 1977, H a l l i d a y and Pate 1976, Haystead and Low 1977, Jones et a l . 1977, K l e t e r and Bakhuis 1972, Walker et a l . 1954, Williams 1969). Non symbiotic b i o l o g i c a l systems, by comparison, have been documented to f i x no more than 70 pounds per acre per year (Williams 1969). Under usual farm p r a c t i c e s amounts of N f i x e d are commonly low - o f t e n below 170 kgs N per hectare. Many c o n d i t i o n s d i c t a t e the a v a i l a b i l i t y o f f i x e d n i t r o g e n a s s o c i a t e d species. E x c r e t i o n appears to be a ready source of transference (Mulder et a l . 1977, V i r t a n e n et a l . 1937) whereas senescence of nodules, r o o t s and top growth l i b e r a t e n i t r o g e n over a longer p e r i o d of time (Walker et a l . 1954). I t i s a l s o suggested (Walker et a l . 1954) that there i s a d i r e c t r e l a t i o n s h i p between the amount of n i t r o g e n r e t a i n e d by c l o v e r and the c o n t r i b u t i o n by c l o v e r to grasses. Clovers have been shown to make a v a i l a b l e to other assoc- i a t e d s p e c i e s , notably grasses, as much n i t r o g e n as they r e t a i n i n t h e i r a e r i a l p a r t s . Fixed n i t r o g e n from e x c r e t i o n and from decaying organic and other s o i l systems are confounded and i t i s d i f f i c u l t to a s s i g n q u a n t i t a t i v e expressions to the components. I t i s considered t h a t c l o v e r i s i n e f f i c i e n t i n comparison to many other higher p l a n t s such as grasses i n the s e q u e s t r a t i o n o f n i t r o g e n from the s o i l (Jones et &1. 1977). Long-term c o n t r i b u t i o n s by white c l o v e r , a f t e r ploughing, have been researched by Williams (1959). He claimed t h a t over equal periods p e r s i s t e n t v a r i e t i e s o f white c l o v e r had a greater e f f e c t on i n c r e a s i n g y i e l d s of crops f o l l o w i n g i n a r o t a t i o n than the l e s s p e r s i s t e n t v a r i e t i e s . He observed that wheat, under h i s c o n d i t i o n s , grown on ground t h a t was occupied by white c l o v e r f o r three years p r e v i o u s l y , y i e l d e d 30% higher than wheat grown on land occupied by white c l o v e r f o r only one year. 9 Although workers have claimed a 200% increase i n forage production by i n c l u d i n g a legume (Dobson and Beaty 1977) i n the forage mixture, the use of white c l o v e r i n pasture and forage seed mixtures d e c l i n e d i n many c o u n t r i e s i n the e a r l y 1950's (Williams 1969). On the other hand, f o r example, the use of inorganic n i t r o g e n f e r t i l i z e r doubled i n B r i t a i n , between the years 1957 to 1967; there, the upper forage y i e l d of a mixed c l o v e r - r y e g r a s s l e y i s ca. 9000 kgs/ha while a pure ryegrass l e y , using up to 400 u n i t s of inorganic n i t r o g e n , w i l l y i e l d twice that f i g u r e , or ca. 18000 kg/ha of dry matter (Chestnutt and Lowe 1969, Cooper 1969, Williams 1969). The reasons f o r the change, to the use of inorganic n i t r o g e n f e r t i l i z e r , are many and may continue as long as nitrogenous f e r t i l i z e r s are r e l a t i v e l y inexpensive. I t i s to be noted however that a r t i f i c i a l f i x a t i o n of atmos- pheric n i t r o g e n i s a high energy consuming process. Measurement of the l e v e l of n i t r o g e n f i x a t i o n on t o t a l n i t r o g e n f i x e d has t r a d i t i o n a l l y been by the K j e l d a h l method ( B u r r i s 1974). Although t h i s i s an accurate means of t o t a l n i t r o g e n measurement i t i s d e s t r u c t i v e of the p l a n t m a t e r i a l . In 1956 both D i l w o r t h and S c h b l l h o r n simultaneously, and independently observed the r e d u c t i o n of acetylene to ethylene i n the presence of a b i o l o g i c a l n i t r o g e n f i x i n g agent (nitrogenase system)(Burris 1975). Koch and Evans (1966) published the f i r s t work i n the use of the method followed by p u b l i c a t i o n s by S c h o l l h o r n and B u r r i s (1967) and Stewart et &1. (1967). The method, known as the acetylene r e d u c t i o n method, has proved to be both s e n s i t i v e and inexpensive w i t h a p p l i c a t i o n both i n the l a b o r a t o r y and the f i e l d . S i n c l a i r et a l . (1967) evaluated the technique and presented the l i m i t a t i o n s on i t s accuracy and a p p l i c a t i o n . Overviews of the technique have been given by Bergersen (1970), B u r r i s (1974) and Hardy et a l . (1968). Several p u b l i c a t i o n s e x i s t on the use of the acetylene r e d u c t i o n tech- nique with v a r i o u s types of assay chambers ranging from 50 ml. syringes by 10 Hardy et a l . (1968), 21 l i t r e p l a s t i c waste paper baskets by Fishbeck e_£ a l . (1973) to p l a s t i c bags by Lee and Yoshida (1977). I t has been used success- f u l l y under f i e l d c o n d i t i o n s (Lee et a l . 1977, Vaughn and Jones 1976) and i n remote areas by S t u t z and B l i s s (1973). White c l o v e r has been s u c c e s s f u l l y studied by the technique ( H a l l i d a y and Pate 1976, Haystead and Low 1977, Masterson and Murphy 1976, Moustafa et a l . 1969, S i n c l a i r 1973) and the same p l a n t s have been repeatedly sampled, i . e . the method may not i n v o l v e d e s t r u c t i o n of the p l a n t m a t e r i a l t e s t e d . The above authors have sampled nitrogenase a c t i v i t y over periods rang- ing from 30 minutes to twenty-four hours a f t e r acetylene i n t r o d u c t i o n . The acetylene r e d u c t i o n technique has been used to measure q u a l i t a t i v e responses by the nitrogenase system to such f a c t o r s as d e f o l i a t i o n or p l a n t to p l a n t v a r i a b i l i t y . The authors c a u t i o n that the i n t e r p r e t a t i o n of q u a n t i t a t i v e measurements can be misleading unless adequate c o n t r o l s are employed, these being isotopes or K j e l d a h l nitrogen determinations. Measurement of ethylene production has been by the use of gas chrom- atography e i t h e r by d i r e c t i n t r o d u c t i o n from the assay chambers or storage i n serum v i a l s . T his method of storage has proved p r a c t i c a l but l i m i t e d i n the length of time one can s t o r e samples before a n a l y s i s . The p u b l i c a - t i o n by M a l l a r d et a l . (1977) o u t l i n e s the c o n s t r u c t i o n and use of a gas chromatograph a p p l i c a b l e to f i e l d use. I t i s capable of d e t e c t i n g ethylene concentrations as low as 10 parts per m i l l i o n . 2.3 Marker Genetics 2.3.1 I n t r o d u c t i o n In the breeding and seed production of white c l o v e r i t i s very u s e f u l to have v i s i b l e p l a n t characters that can be used to i d e n t i f y p l a n t stocks or m a t e r i a l s . They can be used f o r a v a r i e t y of purposes such as the i d e n t - 11 i f i c a t i o n of "mother s t o c k s " and the f i e l d maintenance of c e r t i f i e d s t o cks. In white c l o v e r there are a number of very good d i s t i n c t i v e markers governed by e a s i l y i d e n t i f i a b l e genetic systems. One of these i s the a b i l i t y of c e r t a i n white c l o v e r l i n e s to produce hydrocyanic a c i d (HCN) i n va r y i n g amounts; d e t e c t i o n of HCN can be u s e f u l l y undertaken by employing the simple p i c r i c a c i d chemical t e s t . There are also a s e r i e s o f l e a f mark- ings which are v i s i b l e w i t h the eye and which can be simply c l a s s i f i e d . 2.3.2 Cyanogenesis A comprehensive review of cyanogenic g l y c o s i d e s , w i t h s p e c i a l reference to white c l o v e r , has been published by Jones (1972). C o r k i l l (1942 and 1971) and Daday (1954 a, b, c and 1955) have studied s p e c i a l features of cyano- genesis i n white c l o v e r . " Cyanogenic glucosides can be found i n over s i x t y of the f l o w e r i n g p l a n t f a m i l i e s . There i s v a r i a t i o n w i t h i n f a m i l i e s , genera and species w i t h respect to presence or absence o f cyanogenesis. White c l o v e r may be cyanogenic or acynogenic (Jones 1972). The presence o f cyanoglucosides i n white c l o v e r was apparently f i r s t reported by Mirande (1912) . Cyanogenesis i n white c l o v e r occurs when the enzyme linamarase a c t s on (hydrolyses) the two glucosides l i n a m a r i n and l o t a u s t r a l i n ; gaseous hydrocy- anic a c i d i s released (Daday 1955, M e l v i l l e and Doak 1940) . The process i s u s u a l l y a c t i v a t e d by s t r e s s on the p l a n t or by mechanical damage; c o l d temperatures or mordants such as toluene or chloroform are a l s o able to i n i t i a t e t h i s a c t i v i t y (Jones 1972). Cyanogenesis i s governed by two p a i r s o f genes. One p a i r r e l a t e s to the presence or absence of the cyanoglucosides ( l o t a u s t r a l i n 80% and li n a m a r i n 20%) and the other p a i r to the presence and absence o f the enzyme linamarase. In both p a i r s the gene f o r presence i s dominant ( C o r k i l l 1942, M e l v i l l e and Doak 1940, Pusey 1966) yet the amount of glu c o s i d e i s governed 12 p o s s i b l y by the presence of modifying genes ( C o r k i l l 1942) . Cyanogenesis i s found mainly i n the leaves and p e t i o l e s but apparently i s not a s s o c i a t e d with p l a n t form (Atwood and S u l l i v a n 1943, Daday 1955, Jones 1972); i n New Zealand and the warmer areas of Europe cyanogenesis i s associated w i t h , but not n e c e s s a r i l y the cause o f , g r e a t e r p l a n t f i t n e s s (Bishop and Korn 1969). When cyanogenic p l a n t s are i n j u r e d by f r o s t the enzyme system i s a c t i v a t e d w i t h a subsequent i n t e r n a l r e l e a s e o f hydrocyanic a c i d (Daday 1965). In New Zealand the most pr o d u c t i v e and p e r s i s t e n t types of white c l o v e r are the highest i n cyanophoric p r o p e r t i e s (Atwood and S u l - l i v a n 1943, C o r k i l l 1942, Daday 1955). Because one cannot v i s u a l l y d i s t i n g u i s h cyanogenic and acyanogenic p l a n t s or t h e i r seed, the New Zealand Department of A g r i c u l t u r e employs the p i c r i c a c i d t e s t (Guignard t e s t ) as one of the methods used i n i t s s t r a i n c e r t i f i c a t i o n programme (Foy and Hyde 1937). The frequency of cyanogenic p l a n t s i n a p o p u l a t i o n i s governed by geographic l o c a t i o n and c l i m a t e . Daday (1954 b) reported a decrease i n the frequency of cyanogenic p l a n t s from the Mediterranean r e g i o n northwards to northeastern Europe and which i s s t r o n g l y a s s o c i a t e d w i t h the mean January temperatures (Daday 1954 c, 1965). This was a l s o confirmed by DeAraujo (1976) . Daday a t t r i b u t e d t h i s to a decrease i n the g l u c o s i d e gene frequency and to a l e s s e r amount, the enzyme gene frequency. There i s a s l i g h t d i u r n a l and seasonal v a r i a t i o n i n the amounts of hydrocyanic a c i d released (Caradus and Evans 1977, C o r k i l l 1942). The reasons f o r the c l i n a l d i s t r i b u t i o n of cyanogenesis i n white c l o v e r may be found i n r e p e l l e n t - d e f e n s i v e mechanisms (Wallace and Mansell 1975), but the i n t e r r e l a t i o n s h i p between the p l a n t and i t s users are complex. Molluscs have been reported to consume up to 17% of the l e a f area of acyano- genic p l a n t s i n white c l o v e r (Angseesing and Angseesing 1973) . However 13 d i f f e r e n t species of slugs d i f f e r i n t h e i r preference f o r cyanogenic p l a n t s (Crawford-Sidebotham 1972) ; f o r example the species Agriolimax r e t i c u l a t u s i s not deterred i n i t s e a t i n g of cyanogenic p l a n t s (Bishop and Korn 1969). White c l o v e r has been reputed to cause death i n c a t t l e yet sheep r e q u i r e greater doses i n order f o r i t to be l e t h a l (Todd 1969) . High l e v e l s of hydrocyanic a c i d i n white c l o v e r are of the order of 0.035 percent w h i l e the t o x i c l e v e l f o r sheep i s ca. 0.09 percent (Bishop and Korn 1969) or ca. 2.4 mg/kg body weight (Jones 1972). 2.3.3 Leaf Markings Leaf markings i n the genus T r i f o l i u m are common (Brewbaker 1955) . White c l o v e r d i s p l a y s two d i s t i n c t types, white and red (Cahn and Harper 1976, Carnahan et a l . 1955, Davies 1963). The i n h e r i t a n c e systems f o r both are simple (Brewbaker 1955, Carnahan et a j . 1955, Davies 1963) and are both used as v a l u a b l e v i s u a l aids i n the i d e n t i f i c a t i o n of i n d i v i d u a l clones and s t r a i n s (Cahn and Harper 1976 a, b, Carnahan et a l . 1955, Charles 1968, C o r k i l l 1971, Harberd 1963) . White c l o v e r clones are very r a r e l y s e l f - compatible ( C o r k i l l 1971); these l e a f markings make i t r e l a t i v e l y simple i n maintaining genetic p u r i t y and the i d e n t i f i c a t i o n o f p a r e n t a l l i n e s i n the f i e l d . There appears to be a seasonal e f f e c t i n l e a f mark expression. The white marks are at t h e i r sharpest expression between the months of A p r i l and J u l y w i t h the l e a s t expression from December to January. Cahn and Harper (1976 a, b) observed that sheep p r e f e r p l a n t s w i t h no l e a f markings and show va r y i n g degrees of preference f o r d i f f e r e n t i n t e n s i t i e s of markings. A l s o p l a n t s w i t h no l e a f marks are s u i t e d to long periods of grazing (Charles 1968) and show more r e s i s t a n c e to s t o l o n r o t by f u n g i (Cahn and Harper 1976 b ) . 14 The make-up of the white mark remains to be c o n c l u s i v e l y r e s o l v e d , but a morphological explanation appears to be primary. I t i s recognized (Brew- baker 1955, Carnahan et a l . 1955, E r i t h 1924, Hara 1957) that i t i s assoc- i a t e d w i t h the mesophyll t i s s u e on the upper surface. The p a l l i s a d e c e l l s are l e s s elongated and organized, yet appear to have a greater number of i n t e r c e l l u l a r spaces. The red markings on the l e a f , due to the nature of t h e i r i n h e r i t a n c e , are u s e f u l to p l a n t breeders i n the same way as the white marks. These red markings c o n t a i n anthocyanin (Davies 1963) l o c a t e d i n the epidermal t i s s u e (Carnahan et a l . 1955, K i r k et a l . 1967); expression i s at i t s g r e a t e s t below 10°F. The genetics of the white and red markings have been s t u d i e d by Brew- baker (1955) and by C o r k i l l (1971) . The presence of marks i s dominant to. absence.aid the genes c o n t r o l l i n g c o lour are independent of the genes con- t r o l l i n g cyanogenesis. 2.4.1 Seed Production - General Biology An encompassing t r e a t i s e on the management aspects of white c l o v e r , i n the production of forage and seed as w e l l as animal r e l a t e d f a c t o r s f o r B r i t a i n , i s a v a i l a b l e (L° w e 1969) . I t contains r e l e v a n t a r t i c l e s authored by those working on various aspects of crop management. B u l l e t i n s w i t h r e l a t i v e i n f o r m a t i o n about white c l o v e r f o r the farmer i n B r i t a i n , the United States and Canada are a v a i l a b l e (Dominion Department of A g r i c u l t u r e 1941, United States Department of A g r i c u l t u r e 1915, Ware 1925). The seeding of forages w i t h a small g r a i n companion crop i s a common p r a c t i c e (Hughes et a l . 1966), white c l o v e r being no exception. The choice of a g r a i n crop and i t s seeding r a t e ( s p r i n g wheat, oats or barley) r e s t s l a r g e l y on the edaphic, c l i m a t i c , and economic s i t u a t i o n of the area con- 15 cerned. Smith et a l . (1954) found,;that under t h e i r c o n d i t i o n s the seeding rates of s p r i n g oats, from 24 kgs/ha to .141. kgs/ha,,, had l i t t l e e f f e c t on the establishment of a l f a l f a and red c l o v e r . The favourable e f f e c t s enjoyed by the s e e d l i n g c l o v e r and a l f a l f a p l a n t s under the low seeding r a t e of g r a i n was c a n c e l l e d out by the increased weed p o p u l a t i o n . Under heavy seed- ing rates of g r a i n , good weed c o n t r o l was obtained but moisture and shading were l i m i t i n g f a c t o r s f o r the legume s e e d l i n g s . Seed y i e l d s are c l o s e l y r e l a t e d to the number of i n f l o r e s c e n c e s per acre and the seeds per i n f l o r e s c e n c e (Hawkings 1956) . F l o r a l i n i t i a t i o n i n B r i t a i n , f o r Kent w i l d white c l o v e r , takes p l a c e when ca. 610 growing degree days have accumulated. The daylength t h r e s h o l d f o r f l o r a l bud i n i t i a t i o n i s ca. t h i r t e e n and a h a l f hours (Hagger et a l . 1963). This i s a l s o the - stage when l i g h t p e n e t r a t i o n to the st o l o n s i s important ( Z a l e s k i 1969). Temperatures are a l s o important i n determining f l o w e r i n g and i t s i n t e n s i t y (Garrison and Bula 1961, Thomas 1962). I t i s common p r a c t i c e i n B r i t a i n to graze seed pastures or to d e f o l i a t e i n some other manner p r i o r to the f l o r a l bud i n i t i a t i o n stage. The b e l i e f i s that d e f o l i a t i o n allows l i g h t p e n e t r a t i o n to the stol o n s which, i n t u r n , branch and provide a greater number of s i t e s f o r f l o r a l buds (Haggar et. a l . 1963, Z a l e s k i 1969). The a d d i t i o n of a n i t r o g e n f e r t i l i z e r encourages ve g e t a t i v e growth and consequently reduces the number of flower heads (Anslow 1962). I f d e f o l i a t i o n i s delayed, peduncle length w i l l be reduced and poor p o l l i n a t i o n may r e s u l t (Thomas 1961) . The world average white c l o v e r seed y i e l d i s ca. 200 kgs/ha, with a range of 100 to 600 kgs/ha. Argentina, among c o u n t r i e s , appears to have the highest y i e l d s per acre (FAO of the United Nations 1961). Seed production i n B r i t a i n has a p o t e n t i a l y i e l d of ca. 760 kgs/ha (Davies 1969) yet only •)' - 16 a f r a c t i o n of t h i s p o t e n t i a l i s r e a l i z e d (Haggar et a l . 1963, Hawkins 1960). Harvesting losses i n the form of s h a t t e r i n g and seed head l o s s account r f o r much of t h i s l o s s while s h r i v e l l i n g and i n s e c t damage make up the b a l - ance (Davies 1969, F o r s t e r et a l . 1962). Harvesting when the seed heads are very dry w i l l r e s u l t i n heavy losses due to s h a t t e r i n g on to the ground. The use of a vacuum-type harvester has given an 80% recovery r a t e of seed (Dexter and McKibben 1945). The age of a seed crop i s important i n r e l a t i o n to i t s seed y i e l d c a p a c i t y . Haggar and Holmes (1963 a) reported that w i l d white c l o v e r , which i n the f i r s t year of seed harvest y i e l d e d 132 kgs/ha, by the f i f t h year y i e l d e d o nly 60 kgs/ha of seed. Harvesting g e n e r a l l y commences when 90% of the heads are "brown". A l a t e harvest i s reputed to give increased y i e l d while an e a r l y harvest r e s u l t s i n a lowering of p e r s i s t e n c e i n f u t u r e gen- e r a t i o n s (Haggar and Holmes 1963 b). The c o l o u r i n g of seeds of white c l o v e r i s not uniform; seedsmen p r e f e r seed l o t s c o n s i s t i n g l a r g e l y of yellow seeds; a b r i g h t yellow colour i s b e l i e v e d to be a r e s u l t of h a r v e s t i n g c o n d i t i o n s and to be a s s o c i a t e d w i t h high v i a b i l i t y of seed (Haggar and Holmes 1963 b, Ware 1925). White c l o v e r i s an open p o l l i n a t e d crop and honey bees are important p o l l i n a t o r s . The presence of hives i n a crop have given a 47% increase i n seed y i e l d (Haggar and Holmes 1963 a ) . The recommendations f o r numbers of hives per acre v a r i e s g r e a t l y from country to country. In B r i t a i n one hive f o r every one hectare i s recommended (Davies 1969, Z a l e s k i 1969) and i n New Zealand one hive i s recommended to every three hectares (Davies 1969) . In the United States one hive per s i x hectares appears to be adequate (Anslow 1962) but Green (1957) found that one hive to every four hectares gave an acceptable seed s e t . Pankiw and E l l i o t t (1959) working on a l s i k e c l o v e r 17 i n the Peace R i v e r Region of Canada recommended one hive to one h a l f a hectare. Demand f o r a p e r s i s t e n t white c l o v e r i s high (Haggar and Holmes 1963 b ) ; and management i s an important f a c t o r i n p e r s i s t e n c e . I t i s f o r t h i s reason that buyers of w i l d white c l o v e r , looking f o r seed with high p e r s i s t e n c e , i n s i s t t hat t h i s seed be taken from o l d permanent pastures (Haggar and Holmes 1963 b ) . The tendency f o r seed to be taken from short term l e y s i s reputed t o be a guarantee of the l o s s o f p e r s i s t e n c e . I t i s i n t e r e s t i n g to note that abundant f l o w e r i n g i s u s u a l l y a s s o c i a t e d w i t h a l a c k o f p e r s i s t e n c e (Davies 1969, Gibson 1957). The lack i n replacement of photosynthetic surface when primordia become reproductive w i l l r e s u l t i n poor carbohydrate storage (Beinhart 1963). The l o s s of other features of a s t r a i n are a l s o p o s s i b l e when i t i s grown outside i t s r e g i o n of adaptation (Garrison and Bula 1961). Top growth y i e l d s of white c l o v e r grown i n pure stands i n northern l a t - i tudes range from 2 to 4.5 tons/ha ( A l l e n et a l . 1976, Chestnutt and Lowe 1969, Davies 1969, Ennik 1969). In B r i t a i n i t i s customary to grow,white c l o v e r f o r seed with a companion grass that i s also harvested f o r seed. For white c l o v e r seed pro d u c t i o n , Chestnutt and Lowe (1969) recommend that a v a i l a b l e s o i l phosphorus be above 20 p a r t s per m i l l i o n and potassium above 200 p a r t s per m i l l i o n . In B r i t a i n , f e r t i l i z e r a p p l i e d to maintain these l e v e l s i s between 224 to 448 kgs/ha of superphosphate (40 to 90 kgs of P e r h e c t a r e ) every two years and muriate of potash a p p l i e d each f a l l at r a t e s o f 112 to 224 kgs/ha (67 to 134 kgs/ha K 0)(Haggar and Holmes 1963 b ) . „In the United States s i m i l a r recommendations are made (Caradus and Evans 1977, United States Department of A g r i c u l t u r e 1947). F a l l a p p l i c a t i o n s of f e r t i l i z e r to white c l o v e r are j u s t i f i e d s i n c e there i s new nodal root 18 growth at that time which i s capable o f t a k i n g up the a v a i l a b l e n u t r i e n t s (Caradus and Evans 1977). Page and Thomson (.1976) l i s t s e v e r a l h e r b i c i d e s that can be s a f e l y a p p l i e d to white c l o v e r ; the cur r e n t recommendations f o r c o n d i t i o n s i n B r i t i s h Columbia are made a v a i l a b l e to farmers through the f i e l d crop recommendations guide C B r i t i s h Columbia Department o f A g r i c u l t u r e 1978). 2.4.2 Pests of White Cl o v e r Seed Crops White c l o v e r , l i k e a l l other forage legumes, i s host to an array o f p a r a s i t e s from the animal kingdom. Most are not-host s p e c i f i c and w i l l a t t a c k species other than white c l o v e r . The European c l o v e r seed w e e v i l (Miccotrogus p i c i r o s t r i s (Fab.) has been known to g i v e a l o s s i n white c l o v e r seed y i e l d s o f up to 70% ( S t r i c k - land 1956). Both l a r v a e and a d u l t s are r e s p o n s i b l e f o r economic l o s s e s . The a d u l t s feed on the developing f l o r e t s and forming seed pods, w h i l e the l a r v a e feed on the immature and mature ovules (Swan and Papp 1972). This l a r v a l feeding i s the more s e r i o u s damage (Davidson and P e a i r s 1966, De t w i l e r 1923). Overwintering takes p l a c e i n the a d u l t and egg forms to g i v e a r a p i d b u i l d u p o f the p a r a s i t e i n one season (Morgan-Jones 1950) . The a d u l t o f the l e s s e r c l o v e r l e a f w e e v i l (Hypera n i g r i r o s t r i s Fab.) i s known to cause severe p l a n t i n j u r y i n years t h a t are dryer than normal. The a d u l t s are mainly l e a f f eeders, w h i l e the l a r v a e feed both on the leaves and f l o w e r buds (Swan and Papp 1972). Overwintering takes p l a c e i n the ad u l t form around the crowns o f the c l o v e r o l a n t . One generation a year i s normal although two are p o s s i b l e (Davidson and P e a i r s 1966, Det- W i l e r 1923). The c l o v e r root c u r c u l i o ( S i t o n a h i s p i d u l a Fab.) can be found i n many par t s o f North America (Davidson and P e a i r s 1966, United States Department 19 of A g r i c u l t u r e 1947). The a d u l t s are l e a f feeders but t h i s damage i s not considered to be of economic importance (Swann and Papp 1972). The l a r v a e feed on a l l p a r t s of the root system (root nodules, tap and l a t e r a l roots) i n e a r l y summer and leave c h a r a c t e r i s t i c g i r d l i n g scars e s p e c i a l l y on the tap r o o t . I n j u r y i s cumulative and leads to the entry of pathogens i n t o the p l a n t (Dickason et. a l . 1958, H i l l et a l . 1969, 1971, K i l p a t r i c k and Dunn 1961) r e s u l t i n g i n the l o s s of p l a n t vigour and p e r s i s t e n c e (Dickason et a l . 1968, H i l l et a l . 1971, Pescho 1975, U n d e r h i l l et a l . 1955). Two generations a year are p o s s i b l e ( S t e i n 1970). Other i n s e c t s of economic importance to white c l o v e r come from the f a m i l i e s Aphididae, C u r c u l i o n i d a e , Eurytomidae, C i c a d e l l i d a e , M i r i d a e and Pentatomidae (Davidson and P e a i r s 1966). B i o l o g i c a l c o n t r o l of the i n j u r i o u s i n s e c t pests of white c l o v e r i s exercised by the b e e t l e s , true bugs (Homoptera), f l i e s and wasps, f u n g i , v i r u s and b a c t e r i a (Davidson and P e a i r s 1966). Chemical c o n t r o l i s recommended and i s p r a c t i c a l f o r a l l of the above i n s e c t pests (Dickason et a l . 1958, 1968, Neal and R a t c l i f f e 1975, Turner 1957, U n d e r h i l l et a l . 1955) w i t h v a r y i n g degrees of success. Plant morph- o l o g i c a l c h a r a c t e r i s t i c s o f f e r l i m i t e d c o n t r o l or immunity i n some p l a n t species, notably a measure of r e s i s t a n c e i n Medicago species to the a l f a l f a weevil (Hypera p o s t i c a G y l l ) (Liang and Sorenson 1977). This r e s i s t a n c e i s apparently a s s o c i a t e d w i t h pubescence and v a s c u l a r d i f f e r e n c e s . B i o l o g i c a l c o n t r o l has been e f f e c t i v e l y used i n North America,, notably i n the s t a t e of New York where 1.9 m i l l i o n acres of a l f a l f a are protected from the a l f a l f a weevil (Gyrisco 1977). Molluscs can become economic pests i n c l o v e r i n c e r t a i n years. The 20 common s l u g (Agriolimax r e t i c u l a t u s ) can cause economic damage by l e a f feeding on c l o v e r . Chemical c o n t r o l i s p o s s i b l e by the use of two kgs/ha of a c t u a l metaldehyde i n j e c t e d i n t o the i r r i g a t i o n water. A n a t u r a l c o n t r o l i n white c l o v e r i s through the r e p e l l i n g f a c t o r of cyanogenesis (Howitt 1961). Nematodes (eelworms) can become a pest of white c l o v e r . T h e i r feeding on the roots give r i s e to poor p l a n t growth and poor n i t r o g e n f i x a t i o n . The p r i n c i p a l species are the root l e s i o n nematode (Pratylenchus sp.) ( W i l l i s and Thompson 1977), c l o v e r root nematodes (Heterodera t r i f o l i i and Meloidogyne hapla) and the stem eelworm (Tylenchus sp.) (Goodey 1950, W i l l i s and Thompson 1977, Yeates 1976, Yeates et a l . 1977). Although chemical c o n t r o l i s i n c r e a s i n g i n i t s p r a c t i c a l a p p l i c a t i o n on a f i e l d s c a l e , crop r o t a t i o n i s s t i l l the recommended method (Yeates et a l . 1976). 2.4.3 Diseases of White Clover Seed Crops More than t h i r t y diseases i n white c l o v e r l i m i t the production of forage and seed f o r t h i s crop (United States Department of A g r i c u l t u r e 1947) . "Clover s i c k n e s s " , a catch a l l term, i s of a p r a c t i c a l concern to many growers and farmers (Board of A g r i c u l t u r e and F i s h e r i e s 1913, United States Depart- ment of A g r i c u l t u r e 1924). I t i n v o l v e s a l l the c u l t i v a t e d c l o v e r s yet the causes remain obscure (Mann 1950) . U s u a l l y the symptoms are e i t h e r a d e c l i n e i n p l a n t y i e l d and stand d e n s i t y or the poor establishment of a c l o v e r crop when reseeded w i t h i n four years of a preceeding c l o v e r crop. Several sug- gestions f o r the d e c l i n e have been put forward. These u s u a l l y i n v o l v e a combination of c l o v e r r o t ( S c l e r o t i n i a t r i f o l i o r u m ) and stem eelworm ( D i l l o n Weston 1950) . The v a r i e t y from Denmark, "Pajberg M i l k a " , i s r e s i s t a n t to c l o v e r r o t ( A l d r i c h 1969) . O'Rourke (1969) considers that root r o t complex of white c l o v e r to be the most l i m i t i n g f a c t o r i n the establishment, produc- t i o n and p e r s i s t e n c e df t h i s crop i n I r e l a n d . He considers that the 21 unaccountable f a i l u r e i n c l o v e r p e r s i s t e n c e can be a t t r i b u t e d to two Fusarium species that are r e s i d e n t i n the s o i l . Damage by these f u n g i i s considered to occur only when the p l a n t i s subjected to s t r e s s i n s form; at no other time does damage occur. 22 3. DESCRIPTION OF STUDY AREAS 3.1.1 Creston The Creston v a l l e y i s s i t u a t e d i n south eastern B r i t i s h Columbia and i s approximately 806 kilometers due east of Vancouver. The area occurs i n the P u r c e l l Trench south of Kootenay l a k e at e l e v a t i o n s between 530 to 760 meters above sea l e v e l . The a g r i c u l t u r a l p a r t of the v a l l e y runs i n a south-east to north-west d i r e c t i o n , i s about 24 kilometers long and i s 6 to 10 kilometers wide. I t comprises a t o t a l a rable hectarage of 18,802 hectares. The Creston f l a t s on which white c l o v e r seed production takes place are a l l u v i u m and comprise a t o t a l a r a b l e hectarage of 9,120 hectares (Wittneben and Sprout 1971). The c l i m a t e of the Creston area f a l l s i n t o Kbppen's world c l a s s i f i c a - t i o n as Humid C o n t i n e n t a l w i t h warm summers (Department of Mines and Technical Surveys 1957). The Creston f l a t s r e c e i v e about 2800 growing degree days a year and about 120 f r o s t f r e e days with 175 to 200 m i l l i m e t e r s of p r e c i p i t a t i o n during t h a t p e r i o d . Annual s n o w f a l l i s about 1400 m i l l i - meters. The c l i m a t i c data i s presented i n Figure 3.1.1 ( B r i t i s h Columbia Department of A g r i c u l t u r e 1974; Connor 1949). Six f i e l d s f o r study were chosen f o r t h e i r geographic p o s i t i o n ; a l l f i e l d s chosen had a companion crop seeded with the white c l o v e r ; general management i n a l l f i e l d s chosen was considered to be average or b e t t e r than average. The f i e l d s were located on the a l l u v i a l f l a t s w i t h a d i s t a n c e of 10 kilometers between the southernmost and northernmost f i e l d . The remaining four f i e l d s occurred i n between. Four f i x e d but roughly randomly chosen sampling areas were located w i t h i n each f i e l d . Photographs of each f i e l d and sampling area are found i n Figures 3.1.2, 3.1.3, 3.1.4 and 3.1.5. F i g u r e .3.1.1 Average temperature, p r e c i p i t a t i o n , f r o s t f r e e p e r i o d at Creston, B.C. 2.3 ( r T e m p . °F °C 8 0 2 7 r - Average Temperatures and Precipitation at Creston by Month M a x i m u m . M i n i m u m P r e c i p i t a t i o n 7 0 21 6 0 16 5 0 10 4 0 4 3 0 - 1 2 0 - 7 10 - 1 2 0 - 1 8 1 A v g . f r o s t f r e e p e r i o d ^ 1 i » - A I P t i o n . I n c h e s 8 7 6 5 4 3 2 1 Jan F M A M J J A S O N D M o n t h 24 3.1.2 Comment on F i e l d Management The i n d i v i d u a l farm f i e l d i s the r e s u l t of a complexity of f a c t o r s , b i o l o g i c a l , economic and human. Only a few of the current management f a c t o r s , over which the producer may have some c o n t r o l and which may be considered to have relevance to seed production, are recorded f o r the ' i n d i v i d u a l f i e l d s s e l e c t e d f o r t h i s study. In the i n t e r e s t s of b r e v i t y the management record i s by phrase and includes a few oc c a s i o n a l observa- t i o n s on the development of the seed crop. F i e l d 1: "Wyndell south". This f i e l d i s located at the south end of the v a l l e y adjacent to the A g r i c u l t u r e Canada Research Sub S t a t i o n and belongs to Wyndell Farms L t d . F i e l d acreage - 65 acres (26 h e c t a r e s ) . 1976 - Barley seeded at 90 l b s per acre (100 kgs/ha) with white c l o v e r underseeded at 3 l b s per acre (3.4 kgs/ha). - F e r t i l i z e r a p p l i e d - 22 l b s (25 kgs) N; 66 l b s (74 kgs) P 2 0 5 ; 66 l b s (74 kgs) K 20 as 8-24-24 at seeding time. 1977 - May 15th to 20th - 2 p i n t s per acre (2.3 l i / h a ) MCPB (Tropotox) f o r Canada t h i s t l e (Cirsium Arvense (L.) Scop.) and p e r e n n i a l s o w t h i s t l e (Sonchus arvensis (L.)) c o n t r o l (Frankton 1955). - June 7th to June 30th - Bloom 30% to 100% r e s p e c t i v e l y . - 48 hives of bees introduced (1 hive to 1.4 acres, 0.6 h e c t a r e s ) . - June 22nd - 2 p i n t s per acre (2.3 l i / h a ) Malathion f o r c l o v e r seed weevil c o n t r o l . - J u l y 2nd - Bloom "browning". - August - swathed, combined and mouldboard ploughed. - Clover seed y i e l d 400 lb s / a c a f t e r c l e a n i n g (448 kgs/ha).  26 F i e l d 2: "Eastman". This f i e l d i s loc a t e d i n the middle o f the v a l l e y and belongs to East- man Farms Ltd. F i e l d acreage - 55 acres (22 he c t a r e s ) . 1976 - Spring wheat seeded at 90 lbs/ac (100 kgs/ha) and c l o v e r underseeded at 3 lb s / a c (3.4 kgs/ha). - F e r t i l i z e r a p p l i e d - 6 l b s (6.7 kgs) N; 20 l b s (22.4 kgs) P 2 0 5 ; 20 l b s (22.4 kgs) K 20 as 8-24-24 at seeding time per acre. - June 5th - 10 oz/ac (685 g/ha) of 2,4-D f o r general weed c o n t r o l - October 10th - 6 oz/ac (411 g/ha) MCPA f o r general weed c o n t r o l . 1977 - May 27th - 3 p i n t s / a c (3.4 l i / h a ) MCPB (Tropotox) f o r dande- l i o n s , Canada t h i s t l e and p e r e n n i a l s o w t h i s t l e c o n t r o l . - June 1st to J u l y 2nd - Bloom 30% to 100%. - 45 hives of bees introduced (1 hi v e to 1.2 acres, 0.5 ha). - June 22nd - 1 lb/ac (1.1 kgs/ha) Malathion f o r c l o v e r seed weevil c o n t r o l . - August 20th - swathed, combined and c h i s e l ploughed, - . c l o v e r seed y i e l d 400 lbs/ac a f t e r c l e a n i n g (448 kgs/ha). F i e l d s 3 and 4: "Huscroft" These f i e l d s are loc a t e d on the eastern side of the v a l l e y south of the v i l l a g e o f Wyndell and belong to Huscroft Bros. Farm. F i e l d acreage - 80 acres (32 he c t a r e s ) . 1976 - May 14th - F i e l d 3 (eastern s e c t i o n ) - Barley seeded; F i e l d "4" (west section) Spring wheat seeded. On both the c e r e a l was seeded at 90 l b s / a c r e (100 kgs/ha) and c l o v e r underseeded at 4 l b s / a c r e (4.5 kgs/ha). - F e r t i l i z e r a p p l i e d - 11 l b s (12.3 kgs) N; 22 lb s (24.6 kgs) P 2 0 5 ; 39 l b s (43.7 kgs) K 20; 2 lb s (2.2 kgs) of Boron; as 17-34-0 and 0-0-60 at seeding time. Figure 3.1.4 A e r i a l photograph of f i e l d s 3, h and 5- 28 1977 - May 13th - F i e l d "4" 2.25 p i n t s per acre (2.6 l i / h a ) MCPB (Tropotox) f o r p e r e n n i a l s o w t h i s t l e and dandelion c o n t r o l . - June 7th to June 22nd - 40% to 100% Bloom. - 64 hives of bees introduced (1 hive to 1.3 acres, 0.5 h e c t a r e s ) . - June 22nd - 1.5 p i n t s (1.7 l i / h a ) Malathion f o r c l o v e r seed weevil c o n t r o l . - J u l y 2nd to J u l y 15th - p e r e n n i a l s o w t h i s t l e d e n s i t y high i n p l a c e s . - August - swathed, combined and c h i s e l ploughed; seed y i e l d 400 l b s / a c a f t e r c l e a n i n g (448 kgs/ha). F i e l d 5: O g i l v i e . This f i e l d i s loc a t e d d i a g o n a l l y across the road north- of Huscroft f i e l d and belongs to O g i l v i e farms. F i e l d acreage - 50 acres (20 h e c t a r e s ) . 1976 - Spring wheat, seeded at 90 l b s / a c r e (100 kgs/ha) and c l o v e r underseeded. . \ - F e r t i l i z e r 56 l b s (62.7 kgs) N; 96 lb s (107.5 kgs) P 0 ;'20 lbs (22.4 kgs) k 20 as 11-48-0; 34-0-0 and 0-0-60 at seeding time per acre. - Avadex BW ( t r i a l l a t e ) and MCPB (Tropotox) f o r w i l d oats and general weed c o n t r o l . 1977 - May - heavy i n f e s t a t i o n of dandelions, p e r e n n i a l s o w t h i s t l e and Canada t h i s t l e ; no weed c o n t r o l undertaken. - June 7 to June 22nd - 30% to 100% bloom. - 40 hives of bees introduced (1 hive to 1.3 acres, 0.5 he c t a r e s ) . - June 22nd - 2 p i n t s (2.3 li/ha) Malathion f o r c l o v e r seed weevil c o n t r o l . - J u l y 2nd - Blooms "browning". - August - swathed and combined; c l o v e r seed y i e l d 240 l b s / a c r e a f t e r c l e a n i n g (269 kgs/ha). 29 - October - c h i s e l ploughed. F i e l d 6: "Wyndell North". This f i e l d i s l o c a t e d at the north end of the v a l l e y about one m i l e north-west of the v i l l a g e of Wyndell and belongs to Wyndell Farms. F i e l d acreage - 60 acres (24 he c t a r e s ) . 1976 - Barley seeded at 90 l b s / a c r e (100 kgs/ha) and c l o v e r under- seeded at 3 lbs/ac (3.4 kgs/ha). - F e r t i l i z e r a p p l i e d - 12 l b s (13.4 kgs) N; 36 l b s (40.3 kgs) P 2 0 5 ; 36 l b s (40.3 kgs K 20 as 8-24-24 at seeding time per acre. 1977 - May 15th to 20th - 2 p i n t s per acre (2.3 l i / h a ) _ MCPB (Tropotox) f o r Canada t h i s t l e and per e n n i a l s o w t h i s t l e c o n t r o l . - June 7th to J u l y 2nd - 10% to 100% Bloom. - 44 hives o f bees introduced (1 hive to 1.4 acres, 0.6 h e c t a r e s ) . - June 22nd - 2 p i n t s / a c r e (2.3 l i / h a ) Malathion f o r c l o v e r seed weevil c o n t r o l . - J u l y 2nd - heavy i n f e s t a t i o n of p e r e n n i a l s o w t h i s t l e con- t r o l l e d by c l i p p i n g . - August to September - swathed, combined and mouldboard ploughed. - Clover seed y i e l d 450 lb s / a c r e (500 kgs/ha). 3.1.3 S o i l S e r i e s by F i e l d s The s o i l s of the Creston V a l l e y area where v i r t u a l l y a l l of the white c l o v e r i s grown are developed on reclaimed (dyked) a l l u v i u m deposited i n recent m i l l e n n i a by the Kootenay R i v e r as i t debouched i n t o Kootenay Lake; o l d c h a n n e l l i n g and v a r i a b l e d e p o s i t i o n a l p a t t e r n i n g i s s t i l l v i s i b l e i n the g e n e r a l l y f l a t t e r r a i n ; some m o d i f i c a t i o n by ploughing, " f l o a t i n g " and drainage i s to be seen i n the s o i l p r o f i l e s . To some degree s o i l v a r i a b i l i t y i s r e f l e c t e d i n the s o i l s record by f i e l d and s o i l s e r i e s d e s c r i p t i o n given below. 30 31 F i e l d 1 (65 acres) A l l sampling areas (30 hectares) F i e l d 2 (55 acres) A l l sampling areas (22 hectares) F i e l d 3 § 4 (80 acres) A l l sampling areas (32 hectares) (areas w i t h e a r l y maturity) F i e l d 5 (50 acres) Sampling area 1 (20 hectares)- Sampling areas 2 5 3 Sampling area 4 F i e l d 6 (60 acres) Sampling areas 1 2 (24 hectares) Sampling areas 3 § 4 S o i l S e r i e s (Wittneb.en and Sprout 1971) Benny Kuskanook 7/10 Buckworth 2/10 Kuskanook 7/10 Buckworth 3/10 Buckworth 8/10 Kuskanook 2/10 Rykerts Buckworth Nicks Benny 7/10 Rykerst 3/10 Nicks 8/10 Kuskanook 2/10 S o i l S e r i e s D e s c r i p t i o n Benny Great s o i l group Sub group Parent m a t e r i a l Texture Drainage pH Calcium Magnesium Regosol Gleyed o r t h i c regosol Alluvium Fine sandy loam Imperfect 7.9 moderately a l k a l i n e 25 m.e. per 100 gms high 1.35 m.e. per 100 gms. Med. 32 Potassium White c l o v e r s u i t a b i l i t y Buckworth Great s o i l group Sub group Parent m a t e r i a l Texture Drainage pH White c l o v e r s u i t a b i l i t y Kuskanook Great s o i l group Sub group Parent m a t e r i a l Texture Drainage pH Nitrogen Phosphorous Potassium Calcium Magnesium White c l o v e r s u i t a b i l i t y Great s o i l group Sub group Parent m a t e r i a l Nicks ( F i e l d 5, 6) 0.13 m.e. per 100 gms. High Gl e y s o l Carbonated rego g l e y s o l Alluvium Very f i n e sandy loam Poor 7.9 moderately a l k a l i n e Medium Gle y s o l Carbonated o r t h i c g l e y s o l A l l u v i u m S i l t y c l a y loam Moderately to p o o r l y drained 8.0 moderately a l k a l i n e 0.195% (low) 10.5 ppm (low-med) 0.1 me/100 gms ,(L) 27.55 me/100 gms 1.76 me/100 gms (med) Medium Gl e y s o l Low humic e l u v i a t e d g l e y s o l Alluvium 33 Rykerts ( F i e l d 5, 6) Texture Drainage pH Nitrogen Phosphorous Potassium Calcium Magnesium White c l o v e r s u i t a b i l i t y Great s o i l group Sub group Parent m a t e r i a l Texture Drainage pH Nitrogen Phosphorous Potassium Calcium Magnesium White c l o v e r s u i t a b i l i t y Clay loam Poor to moderately poor 7.8 ( m i l d l y a l k a l i n e ) 0.162% (low) 4,2 ppm (low) 0.11 me/100 gms t 14.88 me/100 gms 3.01 me/100 gms (med) Low Regosol Gleyed o r t h i c Regosol (Cal) Alluvium Fine loamy sand Imperfect 7.5 m i l d l y a l k a l i n e 0.133% (low) 5 ppm (low) 0.07 me/100 gms 18.73 me/100 gms 0.92 me/100 gms Medium to high 34 3.2.1 UBC Study Area The area used f o r the study of white c l o v e r was l o c a t e d at the U n i v e r s i t y o f B.C. at Point Grey. The area i s s i t u a t e d on the west coast of the Lower Mainland and experiences a humid, mesothermal c l i m a t e , marine west coast as found i n KQppen's World C l a s s i f i c a t i o n (Department of Mines and T e c h n i c a l Surveys, 1957). The average c l i m a t i c data are presented g r a p h i c a l l y i n Figure 3.2.1. The average f r o s t - f r e e p eriod i s approximately 260 days, w i t h an approximate p r e c i p i t a t i o n i n the growing season of 275 mm (B.C. Department of A g r i c u l t u r e 1974; Connor 1949). The s o i l i s an upland s o i l developed on g l a c i a l m a t e r i a l . The sub-drainage i s r e s t r i c t e d , w i t h an a c i d s o i l r e a c t i o n of about pH 5.0 ( K e l l y and S p i l s b u r y 1939). The area i s approximately 107 meters above sea l e v e l and the topography i s undulating. The area experiences the same number of d a y l i g h t hours as does Creston.' The land used f o r the t r i a l s was p r e v i o u s l y uncropped except f o r f a l l rye and A u s t r i a n winter peas grown as a green manure crop over the w i n t e r . Barnyard manure was a p p l i e d i n the s p r i n g and t h i s together w i t h the green manure was ploughed under i n the s p r i n g of 1977. The area was harrowed, " f l o a t e d " , and rocks were removed p r i o r to p l a n t i n g o f experimental m a t e r i a l . Figure 3.2.1 Average temperature, p r e c i p i t a t i o n , and f r o s t p e r i o d at the U n i v e r s i t y of B r i t i s h Columbia. T e m p . o o F C 8 0 2 7 1 A V E R A G E T E M P S . A N D P R E C I P I T A T I O N AT U.B.C. BY M O N T H • M a x i m u m • M i n i m u m P r e c i p i t a t i o n 7 0 21 6 0 16 5 0 10 4 0 4 3 0 - 1 2 0 - 7 10 - 1 2 0 - 1 8 A v . F r o s t F r e e P e r i o d P t i o a I I nch . 8 7 6 5 4 3 2 1 J a n F M A M J J y A S O N D e c M o n t h 36 4. OBSERVATIONS AND EXPERIMENTS A. For Creston-based Studies S e l e c t i o n of the f i e l d s and l o c a t i o n s took place on the 11th of May, 1977. The f i e l d s c o n s t i t u t e roughly a north-south t r a n s e c t of the v a l l e y ; s i t e s w i t h i n f i e l d s were lo c a t e d at random but c l u s t e r i n g was avoided. 4.1 Sampling f o r Insects No one method of. assessing i n s e c t kind and abundance i s without d i f - f i c u l t y and c r i t i c i s m . A c c o r d i n g l y , s e v e r a l approaches to assessment and monitoring were undertaken w i t h the a s s i s t a n c e of a student r e s i d e n t i n Creston employed by the B.C. M i n i s t r y of A g r i c u l t u r e . 4.1.1 Sweeps 4.1.1.1 M a t e r i a l s and Methods Three sweeps i n each l o c a t i o n i n each f i e l d on each separate date were made with a 15 inch net. Sweeping took place p r i o r to 08:00 hours to avoid bee a c t i v i t y . Samples were placed i n p l a s t i c bags and f r o z e n . The sweeps took place on the f o l l o w i n g dates i n the summer of 1977: May 19th, June 7th, June 15th, June 20th, June 24th, June 29th, J u l y 8th and J u l y 15th. The average numbers of weevils c o l l e c t e d f o r each f i e l d were converted to 20 sweeps per f i e l d . 4.1.1.2 Observations and Results The r e s u l t s of the sweeps are represented by F i g . 4.1.1. The most s t r i k i n g f e a t u r e i s that there are three species of weevils present i n a l l s i x f i e l d s ( c l o v e r r o o t c u r c u l i o , c l o v e r seed w e e v i l , l e s s e r c l o v e r l e a f w e e v i l ) . There appears l i t t l e overlap between the a d u l t s among species, however, l a r v a e of the c l o v e r root c u r c u l i o are i n evidence i n June. Table 4.1.1 Average number of weevils c o l l e c t e d by sweeping the f o l i a g e at Creston; numbers presented f o r each species by f i e l d and date F i e l d 1- Species May 19 June 7 A B C A B C 14 1 3 Date June 15 June 20 June 24 June 29 J u l y 8 J u l y 15 0.5 5 6.3 7.5 15.4 3.8 1 0.8 0.5 2.1 1.5 0.4 2.9 3 0.4 11 A B C A B C 1 6.0 3 5.4 1 14.2 0.5 15.4 6.0 0.5 17.9 0.4 1.7 0.4 1 0.8 10 0.8 18 A B C A B C 6 1 7 2 3 4.6 7 4.6 1 3.5 4 1 .3 0.5 2.5 1.7 2.5 1 0.8 0.5 0.8 10 5.0 63 22 Weevil species - Clover root c u r c u l i o - A Clover seed weevil - B Lesser c l o v e r l e a f weevil - C Figure 4.1.1 Weevils c o l l e c t e d "by means of sweeping the f o l i a g e i n s i x f i e l d s i n the Creston v a l l e y . The number of weevils i s the average of four s i t e s i n each f i e l d converted to number of weevils f o r twenty sweeps. C o l l e c t i o n s were made on eigh t dates with, a malathion spray c o n t r o l a p p l i e d on the 22nd and 23rd day of June. 3 8 tr. C r e s t o n : S w e e p s F i e l d 1 Clover root curculio i Clover seed weevil • Lesser clover leaf weevil 1 S3 c. i ( H C r e s t o n : S w e e p s F ie ld 4 5H 1_L Clover root curculio I Clover seed weevil * Lesser clover leaf weevil 1 19 15 2 0 24 29 8 15 = 10-4 F ie ld 5 > <a <u E z 0 i ! i i l 24 29 J L - 5 . 19 2 0 8 15 i F i e l d 6 5H i Date: I I 19 MAY 15 2 0 J U N E 24 29 i ' 8 15 , i J U L Y I i I i 39 A d u l t s of the three species of weevil e s s e n t i a l l y occur on three separate occasions w i t h i n the sampled growing season. Larvae of the c l o v e r r oot c u r c u l i o were observed to occur i n June, while the a d u l t s from these l a r v a e , emerged from pupation-. at the end of J u l y , as sampled by p i t f a l l t r a p s . An a e r i a l spray c o n t r o l was a p p l i e d on the 22nd and 23rd of June using Malathion to c o n t r o l the c l o v e r seed w e e v i l . C o n t r o l appeared e f f e c t i v e i n reducing the c l o v e r seed weevil p o p u l a t i o n . The presence of the c l o v e r seed weevil e a r l y i n June i n a l l f i e l d s should warrant concern when t h e i r feeding h a b i t s are taken i n t o c o n s i d e r a t i o n . 4.1.1.3 D i s c u s s i o n Sweeping appears to be an e f f e c t i v e method of assessment of weevil a c t i v i t y . The s t a r t i n g date of May 19th was too l a t e and should have been at l e a s t May the 1st. This would have given a b e t t e r idea of the peak p o p u l a t i o n of the c l o v e r root c u r c u l i o . A l s o , a higher frequency of sweeps per week would have been d e s i r a b l e so that true peaks of a d u l t weevil a c t i v i t y could have been obtained. This would f a c i l i t a t e planning of a, more e f f e c t i v e c o n t r o l programme. The sweeping should also take i n t o account l e a f feeders r a t h e r than j u s t those on the flower p a r t s . 4.1.2 S t i c k y Traps 4.1.2.1 M a t e r i a l s and Methods Three f i e l d s were chosen as s i t e s . These were f i e l d s 1, 5 and 6. This gave a rough r e p r e s e n t a t i o n of the study area from south to north. In each of the three f i e l d s , two l o c a t i o n s f o r traps were chosen at random from four l o c a t i o n s chosen e a r l i e r f o r other purposes. The s t i c k y traps c o n s i s t e d of 9 i n c h by 11 i n c h yellow r a i l r o a d board. "Stickum" was a p p l i e d to one s i d e 40 of the board on s i t e . Two boards were placed on a stake w i t h t h e i r t r a ps three f e e t ..off the ground. One board faced south and one faced north. C o l l e c t i o n dates and periods of exposure were: June 7th, June 24th, J u l y 8th, J u l y 19th and J u l y 27th. When boards were c o l l e c t e d they were wrapped i n Saran wrap and placed i n the f r e e z e r . Assessment o f the c o l l e c t i o n s was based on a v i s u a l e s t i m a t i o n only s i n c e i t was v i r t u a l l y impossible to c l a s s i f y a l l organisms to genus, and to make an accurate count. I t was then decided to make o n l y a v i s u a l assessment and to c l a s s i f y to order only. However, Hymenopterans were counted and represented as average numbers per f i e l d . Thysanopteran numbers were noted on a s c a l e of three, v i z (a) few (10), (b) many (20), and (c) very many (30). Absence o f a bar on the graph i n d i c a t e s that no organ- isms were observed. 4.1.2.2 Observations and Results The r e s u l t s o f the s t i c k y traps are found i n Figure 4.1.2.1. Organisms from the orders Hymenoptera and Thysanoptera occurred i n n o t i c e a b l e numbers. Other organisms which occurred s p o r a d i c a l l y were: l a d y b i r d b e e t l e (Hip- podamia sp.), s t i n k bugs (Pentatomidae), b u t t e r f l i e s (Lepidoptera), weevils (Curculionidae) and f l i e s ( D i p t e r a ) . The order Hymenoptera encompasses several wasps that are known to be p a r a s i t i c and are considered to g i v e some b i o l o g i c a l c o n t r o l . There i s an increase i n the wasp po p u l a t i o n up to June 24th and a drop a f t e r the spray a p p l i e d on June 22nd. A r a p i d buildup was evident a month l a t e r . T h r i p s were present i n June i n f i e l d 5 only and then reappeared i n l a r g e amounts i n the l a t t e r h a l f of J u l y . Not a l l Hymenopterans and Thysanopterans are p a r a s i t i c . 41 Table 4.1.2 Average number of organisms i n groups c o l l e c t e d by means of s t i c k y traps at Creston; numbers presented f o r each group by f i e l d and date. Date F i e l d Group June 7 June 24 J u l y 8 J u l y 19 J u l y 27 1 H 3 24 14 T 20 30 5 H 1 15 2 16 36 T 10 20 30 6 H 2.5 13 2 5 25 T 30 Hymenoptera H Thysanoptera T Table 4.1.3.3 Averag e number of organisms i n groups c o l l e c t e d by means of p i t f a l l traps at Creston ; numbers presented f o r each group by f i e l d and date. Date F i e l d Group June 8 June 28 J u l y 15 J u l y 27 1 B 31 30 32 50 S 16 8 54 41 D 5 2 15 5 B 49 71 43 53 S 35 60 53 24 D 4 7 4 3 6 B 46 46 62 21 S 5 33 15 15 D 1 3 4 7 B S D 42 Figure 4.1.2.1 Assessment o f s t i c k y traps a t Creston; l o c a t e d i n f i e l d s 1, 5 and 6, w i t h two l o c a t i o n s i n each f i e l d and two boards a t each l o c a t i o n . Graph date Sampling p e r i o d June 7th May 30th to June 7th June 24th June 7th to June 24th J u l y 8th June 24th to J u l y 8th J u l y 19th J u l y 8 t h t o J u l y 19th J u l y 27th J u l y 19th to J u l y 27th Numerical Assessment: 10 = Few f o r Thysanoptera 20 = Many 30 = Very Many Numerical Assessment: f o r Hymenoptera Average counts a t two l o c a t i o n s i n three f i e l d s f o r f i v e c o l l e c t i o n dates. Figure 4.1.2.2 Insects caught on s t i c k y traps i n the Creston v a l l e y i n three f i e l d s ; two s i t were l o c a t e d on each, f i e l d and two t r a p were e s t a b l i s h e d at each. s i t e . Sticky traps: Creston 44 4.1.2.3 Di s c u s s i o n S t i c k y traps were u s e f u l to monitor f l y i n g i n s e c t . They have drawbacks, f o r i n s t a n c e , the "stickum" m a t e r i a l i s unpleasant to handle and i f there i s r a i n or dust i t has a tendency to lose i t s e f f e c t i v e n e s s ; b i r d s perch on the boards and p i c k o f f a l o t of the l a r g e r i n s e c t s . Whether the boards faced north or south made l i t t l e d i f f e r e n c e to the type or q u a n t i t y of i n s e c t s c o l l e c t e d , and the traps were not u s e f u l i n i n d i c a t i n g the d i r e c t i o n of i n s e c t m i g r a t i o n on a l o c a l s c a l e . More frequent c o l l e c t i o n s would i n a l l p r o b a b i l - i t y y i e l d i n f o r m a t i o n that would be more v a l u a b l e . 4.1.3 P i t F a l l Traps 4.1.3.1 M a t e r i a l s and Methods The same f i e l d s and l o c a t i o n s were used f o r the p i t f a l l traps as were used f o r the s t i c k y t r a p s . These traps were made using 3 1/2 i n c h wide Mason j a r s which were placed w i t h the top of the j a r l e v e l w i t h the ground. Alc o h o l (70%), used as the k i l l i n g and pr e s e r v i n g medium, was added to each j a r i n the f i e l d . Two traps were placed at each l o c a t i o n ; one a meter north of a post, the other a meter south of the same post. C o l l e c t i o n dates were June 8th (representing May 30th to June 8 t h ) , June 28th (representing June 8th to June 28th), J u l y 8th (representing June 28th to J u l y 8 t h ) , J u l y 15th (representing J u l y 8th t o J u l y 15th), J u l y 27th (representing J u l y 15th t o J u l y 27th). Samples as c o l l e c t e d were placed i n methaldehyde. Samples were grouped according to " a c t i v i t y " and were tabu l a t e d as average numbers per f i e l d per c o l l e c t i o n . 4.1.3.2 Observations and Results The r e s u l t s of the p i t f a l l traps are found i n Figure 4.1.3,1, and the organisms are grouped under the three headings of " B e n e f i c i a l " , "Scavenger", and " D e s t r u c t i v e " (Tables 4.1.3.1 and 4.1.3.2). Such headings are s e l f - 45 Table 4.1.3.1 Organisms c o l l e c t e d by p i t f a l l t r a p s at Creston: Grouping of orders, f a m i l i e s and/or genus by common name i n t o three groups a s s o c i a t e d w i t h t h e i r a c t i v i t i e s , a) B e n e f i c i a l - Predacious) Taxon - ARANEIDA - Staphylinidae - Carabidae - Histeridae Common name - Spiders - Rove beetles - Ground beetles - H i s t e r beetles b) Scavengers Taxon - Silphidae - Scarabaeidae - Nitidulidae - Thysanura c) D e s t r u c t i v e Taxon - Curculionidae - Dermestidae - Tenebrionidae - Elateridae - Chrysomelidae - Deroceras sp. Common name - Burying b e e t l e s - Scarab b e e t l e s - Sap be e t l e s - Spring t a i l s Common name - Weevils - Skin beetles - D a r k l i n g beetles - C l i c k b e e t l e s - Leaf b e e t l e s - Slugs 46- Table 4.1.3.2 ^Qrganisms.QOllected.in p i t f a l l traps at Creston: samples taken on four separate dates from two locations i n each of three f i e l d s . Dates of C o l l e c t i o n s June 8 June 28 J u l y 15 J u l y 27 F i e l d 1 B e n e f i c i a l Scavengers Destructive F i e l d 5 B e n e f i c i a l Scavengers Destructive F i e l d 6 B e n e f i c i a l Scavengers Destructive Spiders Ground beetles Sap beetles Weevils Darkling beetles Sp iders Ground beetles Rove beetles H i s t e r beetles Burying beetles Scarab beetles Weevils Slugs Spiders Ground beetles Rove beetles Burying beetles Scarab beetles Skin beetles Ground beetles Rove beetles Sap beetles Spring t a i l s Burying beetles Weevils Ground beetles Rove beetles H i s t e r beetles Burying beetles Spring t a i l s Sap beetles Slugs C l i c k beetles Skin beetles Leaf beetles Spiders Ground beetles H i s t e r beetles Sap beetles Scarab beetles Skin beetles Spiders Ground beetles Burying beetles Scarab beetles Ground beetles Rove beetles Burying beetles Scarab beetles Spring t a i l s Sap beetles C l i c k beetles Ground beetles Rove beetles Burying beetles Sap beetles Skin beetles. Spring t a i l s Slugs Spiders Ground beetles Rove beetles H i s t e r beetles Burying beetles Scarab beetles Weevils Spiders Ground beetles Rove beetles Burying beetles Spring t a i l s Spiders Ground beetles Rove beetles H i s t e r beetles Scarab beetles Weevils Figure 4.1.3 Graph showing i n s e c t s c o l l e c t e d i n p i t - f a l l t r a p s i n the Creston v a l l e y i n three f i e l d s . Traps were l o c a t e d at twc s i t e s on each f i e l d and two traps were l o c a t e d at each s i t e . Assessment i s the average number of i n s e c t s c o l l e c t e d i n each taxon f o r each date. / o n C r e s t o n : P i t F a i l T r a p s 6 0 - 5 0 - 4 0 - 3 0 - 2 0 10 7 0 - 1 •£ 60- iS 5 0 H l/l 1 40. o u *<5 3 0 E Z 2 0 70 6 0 5 0 4 0 3 0 - 2 0 - 1 0 - F i e l d 1 B S D F i e l d 5 I B S D F i e l d 6 1 J u n e 8 B S D I B S D 4 7 (r. Beneficial I Scavenger " Destructive 3 B S B S D 1 11 B S D B S D J u n e 2 8 J u l y 15 Sample Date J u l y 27 48 explanatory and are used by Borror and Delong (1963). A " b i o l o g i c a l c o n t r o l " appears to be i n e f f e c t i n a l l three f i e l d s and on a l l the dates. The spray c o n t r o l on June 22nd d i d not a f f e c t the "Ben- e f i c i a l " or "Scavenger" organisms to any great extent. 4.1.3.3 D i s c u s s i o n I t was hoped t h a t the p i t f a l l t r a p s would y i e l d more i n f o r m a t i o n on sl u g p o p u l a t i o n s . A v i s u a l i n s p e c t i o n o f the f o l i a g e o f the crop d i d i n d i c a t e feeding by a r a t h e r l a r g e p o p u l a t i o n o f s l u g s . Samples o f slugs c o l l e c t e d were c l a s s i f i e d as the common s l u g Deroceras r e t i c u l a t u m ( M u l l e r ) . P i t f a l l t r a p s proved to f u r n i s h u s e f u l i n f o r m a t i o n on the b i o l o g i c a l con- t r o l i n e f f e c t ; more frequent c o l l e c t i o n s would have been u s e f u l . The monitoring o f slug s and s n a i l s would be b e t t e r undertaken u s i n g b a i t s as desc r i b e d by Crawford-Sidebotham (1972). Weevils c o l l e c t e d on J u l y 27th were those o f the c l o v e r root c u r c u l i o . 4.1.4 S o i l Insect Sampling 4.1.4.1 M a t e r i a l s and Methods A s o i l core o f dimensions 10 centimeters deep by 10 centimeters diameter, g i v i n g a volume of 785 cubic centimeters was used. This i s a commonly used device o f the "plugger" type to give an e s s e n t i a l l y undisturbed c y l i n d e r o f s o i l . A) For r o o t examination 4 dates were sampled w i t h the plugger (May 30th, June 16th, J u l y 14th and August 8 t h ) , and one date (September 25) an a r b i t r a r y q u a n t i t y was sampled from the ploughed f i e l d s . A sample c o n s i s t e d o f two pl u g s , and these plugs were washed c a r e f u l l y to avoi d breakage and l o s s o f r o o t s . Damage assessment on the 30th o f May was as to the presence or absence o f r o o t s c o r i n g . On the 16th June a numerical assessment was a l l o c a t e d ranging from Q to 5 f o r a l l f o u r l o c a t i o n s on each o f s i x f i e l d s . On the 14th J u l y and 4th August o n l y two samples were taken from each f i e l d . 49 B) For i n s e c t examination, sampling dates took place on the 5th August, 18th August and 25th September. The August samples were f r o z e n , w h i le the September samples were st o r e d at 8°c. The method of e x t r a c t i o n s c o n s i s t e d of the use of sieves and dry e x t r a c t i o n s , w i t h l i g h t and heat on the August samples and wet e x t r a c t i o n s on the September samples. In the dry and wet e x t r a c t i o n s p l a s t i c funnels and cheesecloth were used. In dry e x t r a c t i o n s i n s e c t s were a c t i v a t e d so that they migrate away from the l i g h t and heat and then c o l l e c t e d at the base of the f u n n e l . Time f o r e x t r a c t i o n i s approximately 4 days. The wet e x t r a c t i o n procedure i s much the same as the dry except that water i s placed on the sample and a l i q u o t s are taken every h a l f hour as the l i g h t and heat are increased. C) Nematode examinations were undertaken at the A g r i c u l t u r e Canada Research S t a t i o n , Vancouver. Samples to be examined c o n s i s t e d of 4 cores from each f i e l d (with p l a n t s i n s i t u ) placed i n j i f f y pots on the 5th August. The e x t r a c t i o n of nematodes from the roots was by way of m i s t i n g . D) For assessment of pathogens ( f u n g i and b a c t e r i a ) , p l a n t s were taken from f i e l d s 2, 3, 4, and 5 on the 25th September and s t o r e d i n p l a s t i c bags at 8°C. These samples were subsequently examined by Dr. R. Copeman, Depart- ment of P l a n t Science, the U n i v e r s i t y of B.C. 4.1.4.2 Observations and Results A) Root damage r a t i n g s : The r e s u l t s are presented i n Table 4.1.4.1. I t i s noteworthy t h a t damage appears i n almost a l l samples and that the roots d e t e r i o r a t e as the summer progresses. Moreover, damage begins before the end of May. Larvae f i t t i n g the d e s c r i p t i o n given by Davidson and Pe a i r s (1960) of the c l o v e r root c u r c u l i o were observed i n the root zone of each core on dates May 30th and June 16th. B) S o i l i n s e c t examinations using sieves and dry e x t r a c t i o n s proved to be of l i t t l e v alue; i t appeared that most organisms p e r i s h e d i n storage. 50 Table 4.1.4.1 An est i m a t i o n of root damage by date to white c l o v e r p l a n t s i n farmers' f i e l d s i n Creston F i e l d (Wyndell South) Location 1 2 3 4 Date c o l l e c t e d 30/5 + + 16/6 3 (5) 2 (7) 3 (-) 2 (3) 14/7 3 4 4/8 4 4 (Eastman) 1 2 3 4 3 (!) 2 (3) 1 CH) 2 (5) (Huscroft East) 1 2 3 4 3 (-) 3 (") 4 (") 3 (1) (Huscroft West) + + 3 (-) 3 (-) 0 (-) 0 (-) 2 3 (Ogi l v i e ) 1 2 3 4 1 (-) 2 (2) 4 (1) 3 (7) (Wyndell North) 1 2 3 4 1 (2) 1 (3) 2 (4) 3 (2) Damage Rating. a) For date - 30/5/77 v i s i b l e i n s e c t i n j u r y + no v i s i b l e i n s e c t i n j u r y b) For dates 16/6, 14/7, and 4/8 ranking "damage" from 1 to 5 with 1 as very s l i g h t i n j u r y to 5 f o r extensive i n j u r y r e s u l t i n g i n crown r o t . i c) Numbers i n brackets are numbers of l a r v a e c o l l e c t e d i n s o i l and root cores. 51 C) Nematode examinations: The r e s u l t s are presented i n Table 4.1.4.2. The occurrence of Pratylenchus spp. i n f i e l d 2, may be of concern; i t i s to be noted t h a t f i e l d 2 was at one time i n hops. Other f i e l d s are "normal" (personal communication - Dr. McElroy, A g r i c u l t u r e Canada, Vancouver, B.C.). D) P r e l i m i n a r y p l a n t pathogen examinations: Observations i n May r e v e a l e d d i s - orders o f p a t h o l o g i c a l nature i n f i e l d s 3 and 4. Other f i e l d s appeared normal. On September 25th, a f t e r a l l f i e l d s had been ploughed, h e a l t h y p l a n t s were found i n f i e l d 2, w h i l e i n f i e l d s 3 and 4 a f t e r ploughing, a l l p l a n t s examined i n the f i e l d were dyin g . P r e l i m i n a r y pathogen i d e n t i f i c a t i o n from f i e l d s 2, 3, 4 and 5 has i n d i c a t e d the presence of s e v e r a l Fusarium species of f u n g i i n damaged r o o t s . The Fusarium species t h a t occurred predominantly i n f i e l d 2 were not so predominant i n f i e l d s 3, 4 and 5. 4.1.4.3 D i s c u s s i o n I t i s evident from Table 4.1.4.1 th a t most of the root damage by the c l o v e r r o o t c u r c u l i o i s very l i k e l y general throughout the v a l l e y and could have a bearing on the v i g o u r , l o n g e v i t y and seed y i e l d o f white c l o v e r stands. The r o o t damage observed on a l l r o o t s f i t t e d c l o s e l y the d e s c r i p t i o n given by K i l p a t r i c k and Dunn (1961). However, more samples and more sampling dates would be r e q u i r e d to r e v e a l the extent of damage throughout the area. I t i s evident from the absence of l a r v a e i n the J u l y and August samples t h a t most of the i n i t i a l damage occurs i n May and e a r l y June. I t was observed th a t root washing was not e s s e n t i a l , but the general examination of c l o v e r r o o t s i n the f i e l d would p r o v i d e a good i n d i c a t i o n of the s u c c e s s i o n of i n f e s t a t i o n . The presence of Fusarium spp. of f u n g i i n the damaged white c l o v e r roots i s i n agreement w i t h K i l p a t r i c k and Dunn (1961) and a l s o the work by O'Rourke (1969). These two papers i n d i c a t e t h a t Fusarium spp. are normal s o i l r e s i d e n t s 52 Table 4.1.4.2 Nematode counts* obtained by e x t r a c t i o n from s o i l - c l o v e r cores from Creston. F i e l d sampling 5/8/77. Counts as number of nematodes per gram of a i r dry r o o t s . Sampling area Pratylenchus ( s t y l e bearing) 1 2 3 4 Lesion F i e l d 1 0 0 0 0 F i e l d 2 374 331 44 0 F i e l d 3 0 0 0 0 F i e l d 4 0 0 120 0 F i e l d 5 0 0 0 0 F i e l d 6 0 6 0 0 Ditylenchus ( s t y l e bearing) Stem F i e l d 1 0 0 0 7 F i e l d 2 20 0 0 30 F i e l d 3 0 0 0 0 F i e l d 4 0 0 0 20 F i e l d 5 0 0 0 0 F i e l d 6 0 0 5 0 Aphelenchus ( s t y l e bearing) Leaf F i e l d 1 24 21 50 26 F i e l d 2 7 15 0 0 F i e l d 3 0 160 103 20 F i e l d 4 0 86 14 0 F i e l d 5 23 0 0 0 F i e l d 6 0 6 32 0 *Made by the s t a f f of the Research S t a t i o n , A g r i c u l t u r e Canada, Vancouver, B.C. 53 but they enter the p l a n t when i t i s under s t r e s s . I f e e l t h a t the fee d i n g of the c l o v e r r o o t c u r c u l i o on the Creston white c l o v e r i s a major c o n t r i b - u t o r to the entry o f the pathogens i s o l a t e d by Dr. Copeman. 4.2 S o i l Sampling f o r F e r t i l i t y 4.2.1 M a t e r i a l s and Methods In s o i l sampling a one-half i n c h s o i l c o r e r was employed. Cores were taken to plough depth. Subsampling at each f i e l d l o c a t i o n was done on a "square g r i d " p a t t e r n . The dates f o r c o l l e c t i o n were May 30th and August 28th; 48 samples i n a l l were c o l l e c t e d . Major a v a i l a b l e n u t r i e n t s i n the s o i l s o f the study areas were deter- mined usi n g the Morgan's U n i v e r s a l System. S o i l r e a c t i o n was determined usi n g customary procedures by employing a pH meter. 4.2.2 Observations and R e s u l t s A v a i l a b i l i t y of major n u t r i e n t s was s i m i l a r i n a l l f i e l d s and s i t e s w i t h i n f i e l d s . N i t r a t e n i t r o g e n averages were low at 8 kgs/ha f o r the 30th May sampling and at 7 kgs/ha f o r the 5th August sampling. Phos- phorous readings were medium to high at 25 to 50 p a r t s per m i l l i o n . Mag- nesium l e v e l s were very low at 12 p a r t s per m i l l i o n , w h i l e calcium l e v e l s were very high at 250 p a r t s per m i l l i o n . S o i l r e a c t i o n at a l l l o c a t i o n s was m i l d l y a l k a l i n e at pH 7.1 to 7.8. 4.2.3 D i s c u s s i o n The quick t e s t system i s adequate f o r t r o u b l e shooting, but as a f e r t i l i z e r recommendation i t i s not p r e c i s e . The s o i l r e a c t i o n and n u t r i e n t l e v e l s approximate those given f o r the area i n the s o i l survey r e p o r t by Wittneben and Sprout (1971) . The m i l d l y a l k a l i n e r e a c t i o n o f the s o i l coupled w i t h the high l e v e l o f calcium c o u l d have a bearing on the l e v e l o f a v a i l a b l e phosphorous i n the s o i l . 54 4.3 Phytomass Sampling 4.3.1 For Dry Matter Y i e l d s on 30-5-77 4.3.1.1 M a t e r i a l s and Methods Sampling was c a r r i e d out on the 30th May. A one-quarter meter quadrat was used and placed randomly twice at each l o c a t i o n i n each f i e l d . C l i p s of top growth were taken as c l o s e to the ground as p o s s i b l e . The m a t e r i a l was then d r i e d i n the pot-hole d r i e r at U.B.C. and weighed. 4.3.1.2 Observations and Results The r e s u l t s are t a b u l a t e d i n Table 4.3.1.1 and graphed i n Figure 4.3.1.1. I t i s to be seen that there i s a f a i r l y wide d i f f e r e n c e i n y i e l d s between f i e l d s even at a date as e a r l y as May. 4.3.1.3 D i s c u s s i o n More and l a r g e r samples would have given greater p r e c i s i o n ; the sheer volume of samples to store and t r a n s p o r t and the labour i n making p l a n t separations would render the e f f o r t s of questionable worth. 4.3.2 For Dry Matter Y i e l d s on 5-8-77 4.3.2.1 M a t e r i a l s and Methods Sampling was c a r r i e d out on August 5th. The sampling procedure was the same as aforementioned i n S e c t i o n 4.3.1, except that three samples per l o c a t i o n i n each f i e l d were taken. Harvesting was timed to occur j u s t p r i o r to swathing the crop. The samples were a i r - d r i e d at Creston. The m a t e r i a l was transported to Vancouver and processed. Separation of g r a i n stubble from the previous year's crop was done p r i o r to the t a k i n g of t o t a l weight. The samples were weighed a f t e r standing at room temperature f o r a number of weeks. 4.3.2.2 Observations and Results Plant top growth y i e l d s are given i n : Table 4.3.2.1 and i n Figure 4.3.2.1. Again a s u b s t a n t i a l v a r i a t i o n i n y i e l d s between f i e l d s i s recorded. Table 4.3:1.1 Top weight sampling i n s i x f i e l d s i n Creston i n May 1977. 2 .(weights i n gms. per 1/4 m quadrat) •• • No. kgs/ha Mean SD CV% Range Samples F i e l d 1 Wyndell South 3640 91 16 18 62 - 113 8 F i e l d 2 Eastman 2200 55 13 24 35 - 74 8 F i e l d 3 Huscroft East 2200 55 9 16 37 - 63 8 F i e l d 4 Huscroft West 2400 60 6 10 49 - 66 8 F i e l d 5 O g i l v i e 3400 85 17 20 58 - 116 8 F i e l d 6 Wyndell North 3520 88 14 16 73 - 111 8 Table ,4.3.2.1. Top weight sampling i n s i x f i e l d s i n Creston i n August. "..".(weights i n gms. per 1/4 m quadrat) No. kgs/ha Mean SD CV% Range Samples F i e l d 1 Wyndell"South 6040 151 47 31 106 - 261 12 F i e l d 2 Eastman 3640 91 16 18 65 - 122 12 F i e l d 3 Huscroft East 5280 132 19 14 95 - 156 12 F i e l d 4 Huscroft West 5280 132 51 39 68 - 263 12 F i e l d 5 O g i l v i e 6560 164 46 28 87 - 221 12 F i e l d 6 Wyndell North 7320 183 50 27 109 - 248 12 Table 4.3.3.1 Seed weight i n s i x f i e l d s i n Creston , August 1977. 5 (we i g h t s i n gms. per 1/4 m2 quadrat) No . kgs/ha Mean SD CV% Range Samples F i e l d 1 Wyndell South 672 16.8 5.3 31 11.2 - 30.8 12 F i e l d 2 Eastman 468 11.7 1.6 13 9.6 - 15.1 12 F i e l d 3 Huscroft East 972 24.3 4.5 18 16.9 - 29.4 12 F i e l d 4 Huscroft West 756 18.9 8.8 47 6.9 - 28.3 12 F i e l d 5 O g i l v i e 468 11.7 5.6 48 5.3 - 21.1 12 F i e l d 6 Wyndell North 480 12.0 4.0 33 6.7 - 16.8 12 Figure 4.3.1.1 The v a r i a t i o n i n weight of top growth, i n s i x f i e l d s i n Creston, 30th May 1977 ( l ) : Two quadrats from k r e p l i c a t e s i n each f i e l d , showing: a) The a r i t h m e t i c mean f o r each f i e l d • b) The simple range by v e r t i c a l bar c) ± one standard d e v i a t i o n from the mean by h o r i z o n t a l bars Creston: weight of top growth (1) 120 100 80 60 40 20 1 3 Field Figure U.3.2.1 The v a r i a t i o n i n weight of top growth i n s i x f i e l d s i n Creston, August 1977 (2) Three quadrats from h r e p l i c a t e s i n each f i e l d showing - a) The a r i t h m e t i c mean f o r each f i e l d • b) The simple range by v e r t i c a l bar c) +_ one standard d e v i a t i o n from the mean by h o r i z o n t a l bars Creston: weight of top growth (2) 260 240 220 200 180 H 160 k 140 120 100r 80 60 i_ 1 6 Field 58 4.3.2.3 Dis c u s s i o n Harvesting of the m a t e r i a l was c a r e f u l l y undertaken to keep l o s s to a minimum. The small quadrat was u s e f u l i n t h i s respect. S o i l v a r i a b i l i t y can p a r t i a l l y e x p l a i n the large standard d e v i a t i o n s ; i t was f u r t h e r . observed i n one set .within a s i n g l e f i e l d t hat c l o v e r i n c e r t a i n areas of d i f f e r e n t s o i l t e x t u r e would flower prematurely and not be very t a l l , where- as i n other areas c l o v e r remained v e g e t a t i v e and grew v i g o r o u s l y . Disease, pests and other f a c t o r s undoubtedly c o n t r i b u t e d to y i e l d v a r i a b i l i t y . 4.3.3 Seed and I n f l o r e s c e n c e Y i e l d s on 5-8-77 4.3.3.1 M a t e r i a l s and Methods Inflorescences were separated from the r e s t of the m a t e r i a l harvested as per s e c t i o n 4.3.2. They were then counted and passed through the head thresher. The seed was then cleaned by passing through a s e r i e s of s i e v e s , hand winnowed, and f i n a l l y weighed. 4.3.3.2 Observations and Results Seed harvest and number of i n f l o r e s c e n c e s per u n i t area are i l l u s t r a t e d i n Table 4.3.3.1 and 4.3.3.2 and Figures 4.3.3.1 and 4.3.3.2. F i e l d s 2, 5 and 6 gave the lowest y i e l d s and f i e l d s 3 and 4 gave the highest y i e l d s , f o r both seed and i n f l o r e s c e n c e s . The general trend from f i e l d to f i e l d f o r seed y i e l d to approximate i n f l o r e s c e n c e number i s evident. The average number of i n f l o r e s c e n c e s per hectare was estimated to be 11.5 m i l l i o n ; the average seed y i e l d s were estimated to range from 468 to 972 kgs per hectare (418-868 lbs/a c 4.3.3.3 Dis c u s s i o n I t was a n t i c i p a t e d that the small number and s i z e of the samples would r e s u l t i n a r a t h e r l a r g e standard d e v i a t i o n . However i t can be seen that i n c r e a s i n g seed y i e l d tends to r e l a t e to a moderate y i e l d of standing crop; a heavy top growth tends to suppress number of heads and seed y i e l d on a 59 Table 4.3.5.2 Number of heads per u n i t area i n s i x f i e l d s i n Creston taken i n August 1977 No. quadrats/ Mean SD cv% Range Sample F i e l d 1 Wyndell South 323 61 19 232 -- 413 12 F i e l d 2 Eastman 213 55 26 92 -- 314 12 F i e l d 3 Huscroft East 363 55 15 278 -- 435 12 F i e l d 4 Huscroft West 326 78 24 227 -- 465 12 F i e l d 5 O g i l v i e 257 49 19 173 -- 319 12 F i e l d 6 Wyndell North 239 80 33 129 -- 375 12 Table 4.3.3.3 Dependence of seed y i e l d on number of i n f l o r e s c e n c e s per u n i t area. Linear r e g r e s s i o n equations and c o r r e l a t i o n c o e f f i c i e n t s f o r s i x f i e l d s i n Creston, August, 1977. F i e l d 1 Y = 0.98 + 0.05X r = 0. .56 F i e l d 2 Y = 7.21 + 0.02X r = 0, ,73 ** F i e l d 3 Y = 8.89 + 0.04X r = 0. ,52 F i e l d 4 Y = -10.15 + 0.09X r = 0. yg** F i e l d 5 Y = -12.20 + 0.09X r = 0. ,81** F i e l d 6 Y = 4.42 +•0.03X r = 0. .75** r .01(10) = 0.7079** Number of i n f l o r e s c e n c e s - X; seed y i e l d - Y Number of samples per treatment 12 Figure .4.3,3.1 The v a r i a t i o n i n weight of seed from s i x f i e l d s i n Creston, August 1977: Three quadrats from 4 r e p l i c a t e s i n each f i e l d showing - a) The a r i t h m e t i c mean f o r each f i e l d b) The simple range by v e r t i c a l bar c) f_ one standard d e v i a t i o n from the mean by h o r i z o n t a l bars Loir Creston: seed weight 3 0 1 - 25 20 1 5 10 0 ^ L . 1 3 F i e l d 6 Figure 4.3.3.2 The v a r i a t i o n i n the number of heads per u n i t area i n s i x f i e l d s i n Creston, August 1977: Three quadrats from 4 r e p l i c a t e s i n each f i e l d showing - a) The a r i t h m e t i c mean f o r each f i e l d b) The simple range by v e r t i c a l bar c) +_one standard d e v i a t i o n from the mean by h o r i z o n t a l bars CRESTON: Heads Per Unit Area i l l r . 4 5 0 1 4 0 0 3 5 0 -3 3 0 0 \ o a> | 2 5 0 [ Z 2 0 0 150 100 6 F i e l d 62 u n i t area. Table 4.3.3.3 l i s t s the l i n e a r r e g r e s s i o n equations and cor- r e l a t i o n c o e f f i c i e n t s f o r i n f l o r e s c e n c e numbers and seed y i e l d on a u n i t area. I f seed y i e l d i s regarded as the dependent v a r i a b l e there i s a strong suggestion that as numbers of i n f l o r e s c e n c e s increase then seed y i e l d a l s o i ncreases. Hawkins (1956) working w i t h red c l o v e r f i n d s a s i m i l a r r e l a t i o n - s h i p . I f my seed y i e l d s are compared to farmers' y i e l d s , the farmers are experiencing a seed l o s s w h i le h a r v e s t i n g up to 50%. 4.3.4 I n d i v i d u a l Head Examinations 4.3.4.1 M a t e r i a l s and Methods P r i o r to harvest twenty-one i n f l o r e s c e n c e s were taken from each sampling area i n each f i e l d . F i v e heads were s e l e c t e d at random, rubbed to remove the seeds, and then winnowed. The seeds were then counted and examined f o r i n s e c t damage and other un d e s i r a b l e f a c t o r s . 4.3.4.2 Observations and Results I t i s notable that both the average number of seeds per head and standard d e v i a t i o n s are s i m i l a r f o r a l l f i e l d s except f i e l d 5; means l i e between 144 to 161 seeds per head; i n s e c t damaged seeds ranged from 3% to 10% (Table 4.3.4.1 and Figure 4.3.4.1). 4.3.4.3 Di s c u s s i o n The f a c t o r that caused the lowering i n seeds per head i n f i e l d 5 d i d not a f f e c t the number of heads per u n i t area and remains unexplained; perhaps i t could be a t t r i b u t e d to aberrant p o l l i n a t i o n or to e r r a t i c i n s e c t damage. Table 4.3.4.2 shows the "independence" of i n s e c t damaged seed to the i n f l u e n c e of l o c a t i o n . 4.3.5 Leaf Area, P e t i o l e Length and Peduncle Length 4.3.5.1 M a t e r i a l s and .Methods A) Leaf Area: Four leaves and t h e i r p e t i o l e s were c o l l e c t e d at random 63 Table 4.3.4.1 Number of seeds per head i n s i x f i e l d s i n Creston, August 1977. No. heads/ Mean SD CV% Range Sample F i e l d 1 Wyndell South 151 73 48 13 - 259 20 F i e l d 2 Eastman 161 94 58 31 - 376 20 F i e l d 3 Huscroft East 160 71 44 58 - 325 20 F i e l d 4 Huscroft West 144 94 65 36 - 347 20 F i e l d 5 O g i l v i e 97 59 61 37 - 243 20 F i e l d 6 Wyndell North 161 82 51 31 - 311 20 Table 4.3.4.2 Contingency t a b l e f o r i n s e c t -•damaged seed : from i n d i v i d u a l seed~'. heads from Creston f i e l d i n August 1977. Classes are 'percentag e of seeds damaged" F i e l d Name Class 0-5% 5-: 100% T o t a l 1 Wyndell South 4 (6.10) (3 6 .90) 10 2 Eastman 9 (9.14) (5 6 .86) 15 3 Huscroft East 13 (12.19) (7 7 .81) 20 4 Huscroft West 11 (12.19) (7 9 .81) 20 5 O g i l v i e 11 (12.19) (7 9 .81) 20 6 Wyndell North 16 (12.19) (7 4 .81) 20 T o t a l : 64 41 105 Expected values i n brackets 2 Actua l x =5.72 Expected x^ (0.05)(5) = : 11. 07 Figure 4,3,4.1 The v a r i a t i o n i n number of seeds per head i n s i x f i e l d s i n Creston, August 1977: F i v e i n f l o r e s c e n c e s taken from twenty-one i n - fl o r e s c e n c e s c o l l e c t e d i n the f i e l d from four r e p l i c a t e s from each f i e l d showing - a) The a r i t h m e t i c mean f o r each f i e l d • b) The simple range by v e r t i c a l bars c) + one standard d e v i a t i o n from the mean by h o r i z o n t a l bars 400 CRESTON: Seeds per head 350 300 a a> 250 a> a "S 200 a> e z 150 100 50 3 F i e l d 6 65 from each l o c a t i o n i n each f i e l d at the beginning o f J u l y . The l e a f area was estimated i n square centimeters using the method of Wil l i a m s et a l . (1964). B) P e t i o l e Length: Was measured on the same samples as i n 4.3.5 A. Length was measured from the base of the t r i f o l i a t e l e a f to the base of the p e t i o l e where i t j o i n s the p l a n t stem or s t o l o n . C) Peduncle Length: Samples were c o l l e c t e d at the same time and from the same l o c a t i o n . Length was measured from the base of the i n f l o r e s c e n c e to the.point of attachment of the peduncle .to the stem or s t o l o n . 4.3.5.2 Observations and Results A) Leaf Area: A summary of r e s u l t s of the l e a f area measurements i s found i n Table 4.3.5.1 and Figure 4.3.5.1. Leaf area appears to be s i m i l a r i n a l l f i e l d s except 5 and 6, where the upper l i m i t o f the range was n o t i c e - ably higher. By comparing the data w i t h those given i n Figure 4.3.2.1 i t i s evident that a general increase i n l e a f area f o l l o w s an increase i n top growth weight under f i e l d c o n d i t i o n s i n Creston. Mean l e a f area under f i e l d c o n d i t i o n s i n the Creston V a l l e y i s c o n s i s t e n t l y smaller than s i n g l e p l a n t i n g s at U.B.C. B) P e t i o l e Length: The r e s u l t s of the measurements f o r length of l e a f p e t i o l e are found i n Table 4.3.5.2 and Figure 4.3.5.2. The means are s i m i l a r from f i e l d to f i e l d . C) I n f l o r e s c e n c e Peduncle: The r e s u l t s o f the measurements f o r the length of i n f l o r e s c e n c e peduncle are found i n Table 4.3.5.3 and i n Figure 4.3.5.3. Means are s i m i l a r from f i e l d to f i e l d . 4.3.5.3 D i s c u s s i o n The method of l e a f area e s t i m a t i o n by comparing our leaves w i t h those of leaves from samples of known area proved to be r a p i d and r e l a t i v e l y r e l i a b l e . 66 Table 4.3.5.1 Average leaf areas in centimeters for six fields in Creston in July 1977. Mean No. leaves No. (cm) SD CV% Range per sample Field 1 Wyndell South 9 4 44 4 - 15.8 16 Field 2 Eastman 8 2 25 6.3-15.8 16 Field 3 Huscroft East 9 3 33 5 - 12.6 16 Field 4 Huscroft West 9 3 33 6.3-15.8 16 Field 5 Ogilvie 12 4 33 6.3 - 20 16 Field 6 Wyndell North 13 5 38 6.3 - 20 16 Table 4.3.5.2 Average leaf petiole lengths in centimeters for six fields in Creston in July 1977. No. petioles Mean SD CV% Range per sample Field 1 Wyndell South 19 5 26 9 - 2 5 16 Field 2 Eastman 22 3 14 16 - 27 16 Field 3 Huscroft East 18 4 22 11. - 23 16 Field 4 Huscroft West 20 5 25 14 - 29 16 Field 5 Ogilvie 19 5 26 11 - 27 16 Field 6 Wyndell North 21 3 14 14 - 26 16 Table 4.3.5.3 Average (inflorescence) peduncle lengths in centimeters for six fields in Creston, July 1977. No. peduncles Mean SD CV% Range per sample Field 1 Wyndell South 32 4 13 26 - 39 16 Field 2 Eastman 37 4 11 32 - 44 16 Field 3 Huscroft East 34 4 12 27 - 44 16 Field 4 Huscroft West 36 5 14 29 - 45 16 Field 5 Ogilvie 38 5 13 29 - 48 16 Field 6 Wyndell North 37 5 14 29 - 47 16 Figure 4.3.5.1. The v a r i a t i o n i n l e a f area i n s i x f i e l d s i n Creston, Ju l y : 1977: Four leaves ran- domly taken from four r e p l i c a t e s from each f i e l d , showing: a) The a r i t h m e t i c mean f o r each f i e l d • b) The simple range by v e r t i c a l bar c) ± one standard d e v i a t i o n from the mean by h o r i z o n t a l bars CRESTON: Leaf Area 30 r 25 20 h 15h 10h 5h 1 0 L 3 F i e l d 6 Figure 4.3.5-2 The v a r i a t i o n i n l e a f p e t i o l e length. • f o r s i x f i e l d s i n Creston, J u l y 1977: Four p e t i o l e s randomly taken from r e - p l i c a t e s from each, f i e l d showing: a) The a r i t h m e t i c mean f o r each f i e l d • b) The simple range by v e r t i c a l bar c) ± one standard d e v i a t i o n from the mean by h o r i z o n t a l bars CRESTON: Leaf Petiole 6S <r 3 0 r 2 5 2 0 15 10 0<- L 3 F i e l d 5 6 Figure 4.3.5.3 The v a r i a t i o n i n i n f l o r e s c e n c e pedun- c l e l e n g t h f o r s i x f i e l d s i n the Creston v a l l e y , J u l y 1977: Four peduncles ran- domly drawn from four r e p l i c a t e s from each f i e l d , showing: a) The a r i t h m e t i c mean f o r each f i e l d • b) The simple range by v e r t i c a l bar c) one standard d e v i a t i o n from the mean by h o r i z o n t a l bars CRESTON: Infloresence peduncle 45r- 4 0 h 35 30 h 25 20 15 10 1 3 Field 6 70 The comparison of p e t i o l e and peduncle lengths may a f f o r d some measure of assessing a kind of hindrance to the a c t i v i t y of p o l l i n a t o r s . By compar- ing Figures 4.3.5.2 and 4.3.5.3, peduncle length i s on an average 15.8 cms longer than p e t i o l e length. Examination of Table 4.3.5.4 shows l i t t l e r e l a t i o n s h i p between l e a f area and p e t i o l e l e n g t h , or between p e t i o l e length and peduncle length. 4.3.6 Swath Sampling f o r Standing Crop and Seed Weight 4.3.6.1 M a t e r i a l s and Methods Line t r a n s e c t s were l a i d along randomly chosen swaths i n f i e l d s 2, 3 and 6, immediately a f t e r the crop had been swathed by the farmers. Ten samples along a t r a n s e c t were gathered from each f i e l d ; each sample was a one meter length of swath and as wide as the width of swath (a sample thus c o n s i s t e d of more than three square meters of standing crop). The m a t e r i a l gathered was a i r - d r i e d , weighed and then threshed i n the s t a t i o n a r y thresher at U.B.C. Seed was cleaned w i t h the a i d of hand sieves and winnowing. Seed was then weighed. 4.3.6.2 Observations and Results Standing crop y i e l d s are given i n Table 4.3.6.1 and Figure 4.3.6.1. There appears to be a wide range i n y i e l d s between f i e l d s . For f i e l d 6 there appears a wide range of y i e l d s w i t h i n the f i e l d i t s e l f . Seed weight measurements are given i n Table 4.3.6.2 and Figure 4.3.6.2. Seed weights f o l l o w c l o s e l y standing crop y i e l d s i n f i e l d s 2 and 3; however i n f i e l d 6 seed y i e l d s are lower than i n the other two f i e l d s d e s p i t e the r e l a t i v e l y l a r g e y i e l d of standing crop. 4.3.6.3 D i s c u s s i o n By measuring the y i e l d s i n the swath I obtained an approximation of y i e l d s the farmer i s g e t t i n g from h i s combine. However, t h r e s h i n g and seed 71 Table 4.3.6.1 Estimates o f standing crop y i e l d s obtained by sampling swaths i n three Creston f i e l d s , August 1977. A i r dry y i e l d kgs/ha Mean SD CV% Range F i e l d 2 Eastman 2 760 69 7 11 55 - 80 F i e l d 3 Huscroft East 3480 87 12 14 64 - 107 F i e l d 6 Wyndell North 5120 128 32 25 83 - 189 Number of samples from swaths i n each o f three f i e l d s - 10. Table 4 .3.6.2 Estimates of f i e l d seed y i e l d obtained by sampling swaths i n three Creston f i e l d s , August 1977 A i r dry y i e l d kgs/ha Mean SD CV% Range F i e l d 2 Eastman 324 8.1 1.2 15 6.5 - 10 F i e l d 3 Huscroft East 440 11.0 2.7 24 7.2 - 16 F i e l d 6 Wyndell North 364 9.1 1.7 19 7.0 - 13 Number of samples from swaths i n each of three f i e l d s - 10. 2 Sample weights i n gms. a i r dry weight per 1/4 m . Figure 4,3.6.1 The v a r i a t i o n i n standing crop i n three Creston f i e l d s , August 1977: Ten samples from a swath i n each, f i e l d showing: a) The a r i t h m e t i c mean f o r each f i e l d • b) The simple range by v e r t i c a l bar c) ± one standard d e v i a t i o n from the mean by h o r i z o n t a l bars 72. Creston: weight of top growth from swaths. 200 r 180 h 1 6 F i e l d Figure 4.3.6.2 The v a r i a t i o n i n the weight of seed from three f i e l d s i n Creston, August 1977: Ten samples from a swath i n each f i e l d showing: a) The a r i t h m e t i c mean f o r each f i e l d • b) The simple range by v e r t i c a l bars c) ± one standard d e v i a t i o n from the mean by h o r i z o n t a l bars 73 CRESTON: Seed Weight From Swath 25, S co .£ 20[ 01 '3 15 10 3 F i e l d — i 6 74 cl e a n i n g methods d i f f e r . I t was n o t i c e d even at time of my sampling, many heads were l o s t and considerable s h a t t e r i n g of seed pods took p l a c e ; there- f o r e the y i e l d s presented i n Table 4.3.6.2 are lower than t r u e y i e l d s i n the standing crop as measured by quadrat but show s i m i l a r trends. 4.4 Sampling f o r Nitrogen F i x i n g A c t i v i t y 4.4.1 M a t e r i a l s and Methods Two sampling dates were chosen using the acetylene r e d u c t i o n technique f o r determining n i t r o g e n f i x a t i o n r a t e s i n the Creston white c l o v e r seed f i e l d s . The technique was based on that used by H a l l i d a y and Pate (1976). For each f i e l d four p l a n t - s o i l cores were taken with the 10 cm. d i a . plugger to make two samples per f i e l d . The roots were hand-washed with care and the excess water was removed from the r o o t s w i t h paper towels. Each sample (2 cores) was placed i n an assay chamber. The assay chambers were constructed from two l i t e r a c i d b o t t l e s . The bottoms o f the a c i d b o t t l e s had been removed and the edge ground on p l a t e g l a s s to make an a i r t i g h t s e a l when stop cock grease was a p p l i e d . The top of the chamber was f i t t e d w i t h a serum b o t t l e stopper through which syringe needles could pass. F i f t y m i l l i l i t r e s of acetylene were introduced to give a c o n c e n t r a t i o n of 0.03 atm. Incubation l a s t e d f o r four hours and f i v e m i l l i l i t r e samples of "gas" were withdrawn and placed i n seven m i l l i l i t r e v a c u t a i n e r tubes. T o t a l p l a n t n i t r o g e n was obtained by use of the method of Chapman and Pate (1961). Samples from the standing crop as described i n s e c t i o n s 4.3.1 and 4.3.2 were used f o r determining t o t a l p l a n t N. A check on the accuracy and p r e c i s i o n of the procedure was performed on standard samples of known composition obtained from Canada Department of A g r i c u l t u r e , Ottawa. 4.4.2 Observations and Results Samples from the acetylene r e d u c t i o n t r i a l s have yet to be analyzed f o r 75 ethylene. The r e s u l t s o f the t o t a l p l a n t n i t r o g e n f i x e d are given i n Table 4.4.1. I t appears that most a c t i v i t y i n f i x a t i o n o f atmospheric n i t r o g e n f o r white c l o v e r under Creston con d i t i o n s , i n the crop's second year, i s i n the e a r l y p a r t o f the summer. I t should be observed t h a t i n some cases there i s a net l o s s i n N i n the l a t t e r part of the growing season. 4.4.3 D i s c u s s i o n The use o f g l a s s b o t t l e s as assay chambers under f i e l d c o n d i t i o n s a t Creston proved to be clumsy and slow. Chambers th a t were more f l e x i b l e which could be taken onto the f i e l d would have been more p r a c t i c a l . P l a s t i c bags as o u t l i n e d by Lee et a l . (1977) would have been f a r more p r a c t i c a l . 4.5 Mowing T r i a l s 4.5.1 M a t e r i a l s and Methods F i e l d 6 was chosen f o r t h i s t r i a l and two l o c a t i o n s i n the f i e l d were s e l e c t e d . At both l o c a t i o n s on the 16th June, 3 s t r i p s 3 f e e t wide and 10 meters long were mown as c l o s e to the ground as p o s s i b l e . Spaced between mown s t r i p s were unmown s t r i p s one meter wide and h a l f a meter wide r e s p e c t - i v e l y . H a r v e s t i n g took p l a c e on the 5th August and 3 samples o f each t r e a t - ment, both cut and uncut, were taken. Samples were a i r - d r i e d , weighed and threshed. 4.5.2 Observations and Results T o t a l weight of the cut areas was on an average 18% lower than the uncut areas. Blossom numbers appeared fewer on the cut area. Although a l l the samples were threshed, the seed was found to be im p o s s i b l e to separate from the concomitant m a t e r i a l . 4.5.3 D i s c u s s i o n Mowing i n the middle of June was about a month too l a t e . The crop was i n the process of blooming and the t o t a l r e s u l t was a lowering o f the top growth y i e l d s and numbers o f blossoms. I f mowing i s to be undertaken to 76 Table 4.4.1 Y i e l d of N. i n kgs/ha for standing crops i n 6 Creston f i e l d s . F i e l d Location Date: 30-5-77 Date: 5-8-77** 1 WS 1 109.4 19Q.6 2 110.9 1Q6.1 3 100.2 106.9 4 125.3 137.6 2 E 1 43.5 74.1 2 60.2 71.6 3 60.2 117.4 4 49.2 66.5 3 HE 1 77.0 135.0 2 71.2 143.4 3 49.7 139.1 4 70.6 106.1 4 HW 1 68.3 116.0 2 33.9 116.7 3 76.5 183.7 4 67.8 81.4 5 0 1 139.1 211.2 2 121.3 167.8 3 90.5 78.1 4 109.3 141.3 6 WN 1 122.3 285.1 2 103.8 91.0 3 144.9 156.6 4 113.8 125.1 * Kjeldahl determination ** T o t a l n i t r o g e n i n c l u d e s a l l top growth i n c l u d i n g seed. The seed n i t r o g e n taken from standard t a b l e s by M i l l e r (1958). 77 reduce v e g e t a t i v e growth i n favour of seed production i t should be done no l a t e r than the end of May i n the Creston V a l l e y . 4.6 Coated Seed T r i a l The coating o f c l o v e r and other seeds to improve establishment has been i n existence f o r s e v e r a l years. The method used f o r the Creston t r i a l s was developed i n A u s t r a l i a and New Zealand as a means of i n o c u l a t i n g white c l o v e r seed. The expectation i s that greater numbers of the r h i z o b i a w i l l be r e t a i n e d on the coated seed and that t h e i r s u r v i v a l i s insured up to the time of p l a n t i n g . The process i s no longer confined to legumes and i s becoming a popular means of applying p l a n t n u t r i e n t s to the seeds of many crop species. 4.6.1 M a t e r i a l s and Methods The t r i a l was undertaken on the M u l l i g a n farm. The seed used was of Creston o r i g i n and the coating process was done by Cel P r i l I n d u s t r i e s Inc., Manteca, C a l i f o r n i a . On the 16th June the t r i a l was l a i d out and seeded on a three by three L a t i n square design; each u l t i m a t e p l o t was three meters by three meters. Treatments were a) coated seed, b) standard i n o c u l a t i o n , c) not i n o c u l a t e d (see t r i a l at U.B.C. s e c t i o n 4.11). 4.6.2 Observations and Results R a i n f a l l a f t e r seeding was i n s u f f i c i e n t to produce a good establishment; consequently the t r i a l was abandoned. 4.7 F e r t i l i z e r T r i a l 4.7.1 M a t e r i a l s and Methods The t r i a l was undertaken on the M u l l i g a n farm. Seed f o r t h i s t r i a l was of Creston o r i g i n . On the 16th of June the t r i a l was l a i d out i n a s p l i t p l o t design w i t h three r e p l i c a t i o n s . Each p l o t was two meters by two meters. The t r i a l was al s o seeded on the 16th June. The f o l l o w i n g were the treatments 78 and i n each r e p l i c a t i o n , each treatment had an untreated adjacent p l o t : a) Nitrogen at 100 kgs per hectare b) S u l f u r at 10 kgs per hectare c) Boron at 2 kgs per hectare d) Molybdenum at 1 kg per hectare e) Calcium at 70 kgs per hectare f) Nitrogen at 65 kgs per hectare Phosphorous at 80 kgs per hectare Potassium at 50 kgs per hectare (K 20) 4.7.2 Observations and Results R a i n f a l l a f t e r seeding was i n s u f f i c i e n t to produce a stand; consequently the t r i a l was abandoned. 4.8 Sampling f o r Cyanogenesis i n Creston White Clover 4.8.1 M a t e r i a l s and Methods ' On the 1st J u l y a l l f i e l d s were sampled f o r cyanogenesis. At 09:00 hours 5 samples each of 150 mg. of l e a f t i s s u e , from each l o c a t i o n i n each f i e l d , were placed i n 10 mm x 120 mm t e s t tubes. Samples were b r u i s e d , 10 drops of chloroform added, a s t r i p of p i c r a t e paper was placed i n the tube and h e l d i n place by a rubber stopper. Samples were incubated f o r 24 hours at 22°C. 4.8.2 Observations and Results No r e a c t i o n was observed a f t e r 24 hours i n any sample from Creston. 4.8.3 D i s c u s s i o n This would then agree with Daday's (1954 b and c) observations on the decrease i n numbers of white c l o v e r p l a n t s g i v i n g a cyanogenic r e a c t i o n 79 where there i s a decrease i n the average January isotherm. B. Studies Undertaken at the U n i v e r s i t y of B.C. 4.9 S t r a i n E v a l u a t i o n Using Groups of S i n g l e Plants 4.9.1 General Comments on Experimental Design and Layout Seeds were obtained from B u c k e r f i e l d s L t d . , Vancouver, B.C, the Ce n t r a l Experimental Farm, A g r i c u l t u r e Canada, Ottawa, and the State U n i v e r s i t y of Oregon, C o r v a l l i s , Oregon. Twenty separate s t r a i n s or l o t s were gathered; Table 4.9.1.1 gives the o r i g i n s and 1000 seed weights. Seed l o t s from Creston are a l l designated as Canada No. 1 seed. Seed l o t s used i n my t r i a l s came from l o t s harvested on i n d i v i d u a l farms; seed f o r grower p l a n t - ings may w e l l have come from other growers i n the Creston area but i t i s u n l i k e l y that much seed i n recent years has come from outside of the Creston area. Seeds were planted as i n d i v i d u a l s i n the greenhouse on March 4, 1977. On the 26th A p r i l they were moved to the c o l d frames f o r hardening o f f . In May the f i e l d s i t e was prepared at U.B.C. and a b a s i c a p p l i c a t i o n of commercial f e r t i l i z e r was a p p l i e d . The rat e s of 350 kgs/ha 0-20-0 (70 kgs/ha P 2° 5) a n d 1 4 2 kgs/ha 0-0-60 (85 kgs/ha K 20) were used. Plants were e s t a b l i s h e d i n the f i e l d on the 5th and 6th May at a spacing of 65 cms between p l a n t s and 1 meter between rows of 5 p l a n t s . The twenty s t r a i n s were at random i n each of four b l o c k s ; each s t r a i n t h e r e f o r e was represented by f i v e p l a n t s i n u l t i m a t e p l o t s and i n four blocks to give a t o t a l r e p r e s e n t a t i o n of 20 i n d i v i d u a l p l a n t s per s t r a i n . Measure- ments and observations were made on i n d i v i d u a l p l a n t s . 4.9.2 V a r i a t i o n i n Flowering by Date 4.9.2.1 M a t e r i a l s and Methods The assessment of f l o w e r i n g was done by counting the number of i n f l o r - 80 Table 4.9.1.1 Weight of seed from twenty s t r a i n s of white c l o v e r planted at u . B.C.: weight i n grams f o r 1000 seeds f o r each i s t r a i n . S t r a i n O r i g i n A (Piper) Creston 0. 7774 grams B (Ordek) Creston 0. 6020 grams C (O.C. Ranch) Creston 0. 7639 grams D (Huscroft) Creston 0. 7553 grams E (Moon) Creston 0. 7417 grams G (Stager) Creston 0. 7662 grams H (Staples) Creston 0. 7586 grams K ( O g i l v i e ) Creston 0. 8005 grams L ( S u t c l i f f e ) Creston 0. 7314 grams M (Barbian) Netherlands 0. ,6232 grams 0 (Pertina) Netherlands 0. ,7379 grams P (Tohoku) Japan 0. ,4799 grams R ( K i v i ) Germany 0. ,6782 grams S (Daenok) Denmark 0. ,7959 grams U (Pajberg) Denmark 0. ,6658 grams T (L51-6-40) L o u i s i a n a 0. .5708 grams V (L75-614-S1) L o u i s i a n a 0, .6217 grams W (L51-6LAWC-50) Lou i s i a n a 0, .6142 grams X (L081-007-1344) Lo u i s i a n a 0, .5999 grams Y (L081-007-2675) Lo u i s i a n a 0 .6002 grams 81 escences that had at l e a s t one f l o r e t i n f u l l bloom on each p l a n t . Observa- t i o n of f l o w e r i n g took place on three dates: June 8th, June 22nd and J u l y 19th. 4.9.2.2 Observations and Results The F-test i n the a n a l y s i s of v a r i a t i o n suggest d i f f e r e n c e s between s t r a i n s and between dates. The observations are l i s t e d i n Tables 4.9.2.1 4.9.2.2 and 4.9.2.3 and Figures 4.9.2.1, 4.9.2.2 and 4.9.2.3. Table 4.9.2.1 gives the mean number of heads i n flower per p l a n t by s t r a i n and the per- centage of p l a n t s without blossoms by date. The s t r a i n s are ranked; a s t r a i n o f course w i l l not n e c e s s a r i l y have the same rank on each date. Table 4.9.2.2 d i s p l a y s the occurrence of the same s t r a i n s w i t h i n a rank through the two f o l l o w i n g dates: June 22nd and J u l y 19th. A prominent feature i s that the e a r l y blossoming p l a n t s and s t r a i n s tend to bloom more p r o f u s e l y throughout the season; p l a n t s and s t r a i n s producing few or no blossoms e a r l y i n the season tend s t r o n g l y to continue to remain v e g e t a t i v e and poor bloomers. Tables 4.9.2.1, 4.9.2.2 and 4.9.2.3 i l l u s t r a t e the f l o w e r i n g response at U.B.C. f o r the twenty s t r a i n s . A l l of the s t r a i n s of Creston o r i g i n rank w i t h i n the f r e e f l o w e r i n g twelve s t r a i n s through the f l o w e r i n g season. 4.9.2.3 Di s c u s s i o n Flowering of the white c l o v e r p l a n t i s a response to a combination of temperature and day length. Crowder (1960) observed that s t r a i n s of white c l o v e r from the more northern or southern l a t i t u d e s would not flower f r e e l y under h i s con d i t i o n s i n Colombia. On the other hand my t r i a l s r evealed that the two s t r a i n s of warmer l a t i t u d e s d i d not flower as f r e e l y as those from the cooler l a t i t u d e s . Free f l o w e r i n g s t r a i n s are important f o r seed produc- t i o n and the Creston s t r a i n s , compared to the remaining s t r a i n s , are con- s i d e r e d to be good seed producers. Table 4.9.2.1. Twenty str a i n s grown at U.B.C. ranked according to average blossom number per plant and percentage of plants without blossoms for three dates Rank: 1 -5 Rank: 6 - 10 Rank: 11 -15 Rank: 16-20 Date 8-6 S t r a i n A U C 0 G M B L S D R K H P E W V Y X T Mean Blossom #/plant .95 .85 .75 .50 .45 .45 .35 .35 .35 .33 .20 .20 .15 .10 .05 .05 .05 .00 .00 .00 % No Blossoms 60 75 65 70 85 70 80 85 80 73 70 85 95 90 95 95 95 100 100 100 Date 22-6 S t r a i n B D U E H P L S G A R K C W M . 0 Y V X T Mean Blossom #/plant 3.25 2.95 2.40 2.35 2.20 2.0 1.65 1.65 1.5 1.4 1.00 0.70 0.70 0.60 0.50 0.50 0.35 0.05 0.00 0.00 % No. Blossoms 20 27 50 40 65 25 65 45 60 70 65 70 60 80 85 80 80 95 100 100 Date 19-7 S t r a i n B U . H L W A D Y E G K C X P M R S T V 0 Mean Blossom #/plant 28.55 24.25 23.70 22.30 21.30 20.95 20.33 20.05 19.75' 16.15 15.50 13.95 13.65 12.9 12.85 12.7 12.20 11.70 11.50 6.40 % No. Blossoms 0 5 10 5 20 10 10 5 15 30 15 20 25 10 10 35 25 5 30 25 Figure 4.9.2.1 The response i n f l o w e r i n g hy twenty •':': s t r a i n s of white c l o v e r on the 8-6-77; the twenty s t r a i n s at random i n each of four b l o c k s ; each s t r a i n represented by f i v e p l a n t s i n u l t i m a t e p l o t s ; u l t i m a t e p l o t s l o c a t e d at random w i t h i n each bl o c k . The Creston s t r a i n s represented by a hatched v e r t i c a l l i n e . The other non Creston s t r a i n s repre- : "', sented by a s o l i d v e r t i c a l l i n e . U . B . C . - M e a n No. Of F l o w e r s Per P lan t O n 8 - 6 - 7 7 S t r a i n s Of C r e s t o n O r i g i n I P e r c e n t a g e Of P l a n t s W i t h N o I n f l o r e s c e n c e • O O Z c o 0) 3 1.0 0.5 O l • • # • # # # • • • • • M00% i _ L J I L 50% A U C O G M B L S D R K H P E W V Y X T S T R A I N Figure 4.9.2.2 The response i n f l o w e r i n g by twenty s t r a i n s of white c l o v e r on the 22-6-77; the twenty s t r a i n s at random i n each of four b l o c k s ; each, s t r a i n represented by f i v e p l a n t s i n u l t i m a t e p l o t s ; u l t i m a t e p l o t s l o c a t e d at random w i t h i n each bl o c k . The Creston s t r a i n s represented by a hatched v e r t i c a l l i n e . The other non-Creston s t r a i n s repre- sented by a s o l i d v e r t i c a l l i n e . 3.o r i3.3 U.B.C- Mean No. Of Flowers Per Plant On 22-6-77 Strain Of Creston Origin \ Percentage Of Plants With No Inflorescence • 2.0 o o Z c o 1.0 o i B t • • E H 0 0 ° / o r -50% L-0% U H S O A R K C W M O STRAIN oO Figure 4.9.2.3 The response i n f l o w e r i n g by twenty s t r a i n s of white c l o v e r on the 19-7-77; the twenty s t r a i n s at random i n each of four b l o c k s ; each s t r a i n represented by f i v e p l a n t s i n u l t i m a t e p l o t s ; u l t i m a t e p l o t s l o c a t e d at random w i t h i n each bl o c k . The Creston s t r a i n s represented by a hatched v e r t i c a l l i n e . The other non-Creston s t r a i n s repre- sented by a s o l i d v e r t i c a l l i n e . 30 U.B.C- Mean No. Of Flowers Per Plant On 19-7-77 Strains Of Creston Origin i Percentage Of Plants With No Inflorescence • 20 o 6 Z c o 10 0' • t • ± m • t i • M 0 0 % i-0% B U H W M STRAIN 0 0 5 T 86 Table 4.9..2. 2 R e l a t i o n s h i p of e a r l i n e s s i n f l o w e r i n g to the number of i n f l o r e s c e n c e s produced; occurrence of number of s t r a i n s w i t h i n ranks f o r two dates. Date 19/7 Rank 1-5 6-10 11-15 16-20 1- 5 3 2 0 0 Date 6-10 1 2 1 1 22/6 11-15 1 0 3 1 16-20 0 1 1 3 Ranks correspond to order w i t h i n a s c a l e of twenty. 87 4.9.3 V a r i a t i o n i n Leaf Area 4.9.3.1 M a t e r i a l s and Methods C o l l e c t i o n s of leaves and p e t i o l e s were made on J u l y 20th and October 13th. C o l l e c t i o n s were made by t a k i n g the t h i r d open l e a f and p e t i o l e from the end of a s t o l o n and another l e a f and p e t i o l e from the centre o f the p l a n t . These samples were considered new and o l d r e s p e c t i v e l y . The t r i f o l i a t e l e a f area estimates were made using premeasured leaves as o u t l i n e d by Williams et a l . (1964). Area estimated was i n square centimeters. 4.9.3.2 Observations and Results The r e s u l t s from the samples taken on two dates are found i n Tables 4.9.3.1 and 4.9.3.2. The r e s u l t s are a l s o portrayed i n Figures 4.9.3.1 and 4.9.3.2. The F-test i n the a n a l y s i s of v a r i a t i o n suggests s i g n i f i c a n t d i f f e r e n c e s , between s t r a i n s and between dates f o r l e a f area. 4.9.3.3 D i s c u s s i o n Mature leaves produced l a t e r i n the season are sm a l l e r than those produced e a r l i e r . These r e s u l t s are s i m i l a r to those reported by Beinhart (1963) . In the Creston s t r a i n s there i s as great a range i n v a r i a b i l i t y as i n other s t r a i n s ; the l e a f area means f o r Creston s t r a i n s show that the Creston white c l o v e r s t r a i n s are indeed intermediate. S t r a i n "M" from the Netherlands i s more o f a;. : wild- "type. Comparative i n f o r m a t i o n i s provided i n contingency t a b l e s . The la r g e Chi-square values suggest that l e a f area d i f f e r e n c e s are not random d i f f e r e n c e s under the con d i t i o n s of t h i s t r i a l but are as s o c i a t e d by s t r a i n . King (1961) found d i f f e r e n c e i n l e a f area to be governed by environmental f a c t o r s . Another i n t r e s t i n g feature i s the increase i n l e a f area, by the Louisi a n a s t r a i n s , f o r the f a l l grown m a t e r i a l . This could be a f a c t o r i n carbohydrate storage. 88 Table 4.9.3.1 Leaf area i n square centimeters f o r i n d i v i d u a l p l a n t s i n twenty s t r a i n s grown i n a uniform nursery at U.B.C. Sampling date 20-7-77Cl) No. leaves S t r a i n Source ;.per sample. Mean SD CV% Range A Creston 40 14.5 4.4 30 8 - 20 B Creston 40 14.0 5.0 36 6.3 - 20 C Creston 40 14.7 4.6 31 6.3-25.1 D Creston 30 14.9 5.2 35 6.3-25.1 E Creston 38 15.0 5.3 35 6.3-25.1 G Creston 40 13.0 4.7 36 6.3 - 25.1 H Creston 40 14.9 4.1 28 8 - 25.1 K Creston 40 14.7 4.5 31 8 - 2 0 L Creston 40 14.2 4.0 28 8 - 20 M Netherlands 40 7.7 2.3 30 4 - 15.8 0 Netherlands 40 14.7 4.8 33 6.3-25.1 P Japan 40 18.0 5.3 29 6.3 - 29 R Germany 40 10.8 3.8 35 6.3 - 20 S Denmark 40 15.6 4.3 28 8 - 25.1 U Denmark 40 13.1 4.9 37 5 - 25.1 T Loui s i a n a 40 12.9 4.1 32 4 - 2 0 V Loui s i a n a . 40 12.0 3.2 27 5 - 2 0 W Lo u i s i a n a 40 11.4 4.1 36 6.3 - 20 X L o u i s i a n a 40 15.3 4.1 27 8 - 25.1 Y Lo u i s i a n a 40 12.9 3.8 29 6.3-25.1 Figure 4.9.3.1 The v a r i a t i o n i n l e a f area on the 2 0 - 7 - 7 7 ( l ) f o r twenty s t r a i n s at random i n each of four b l o c k s ; each s t r a i n represented by f i v e p l a n t s i n u l t i m a t e p l o t s ; u l t i - mate p l o t s l o c a t e d at random w i t h i n each bl o c k , showing: a) The a r i t h m e t i c mean f o r each s t r a i n • b) The simple range by v e r t i c a l bar c) ± one standard d e v i a t i o n from the mean by h o r i z o n t a l bars 3 0 r U . B C . P l o t : leaf a r e a 1 25 20\ E U c < U J < 15 10 130 25 H20 15 10 A B C D E G H K L M O P R S U T V W X Y , J v . I \ „ I v , * , / v -V y • Crest. Neth. Ja. Ger. Den. Louis. CO S T R A I N 5T* 90 Table 4.9.5.2 Leaf area i n square centimeters f o r i n d i v i d u a l , p l a n t s : i n twenty s t r a i n s of white c l o v e r grown i n a uniform nursery at U.B.C. Sampling date 13-10-77(2) No. leaves •ain Source per sample' Mean SD ' CV% Range A Creston 20 7.5 2 .3 31 4 - 12, ,6 B Creston 20 8.4 2 .3 27 5 - 12. ,6 C Creston 20 9.3 2 .8 30 5 - 15. ,8 D Creston 10 9.6 2 .0 21 6, .3 - 12. .6 E Creston 18 6.4 2 .7 42 2, .5 - 12. ,6 G Creston 20 8.2 2 .5 30 5 - 12. ,6 H Creston 20 9.5 1 .9 20 6. .3 - 12. .6 K Creston 18 8.1 2 .7 33 6. .3 - 15, .8 L Creston 20 7.2 2 .2 31 2 - 10 M Netherlands 20 4.5 1 .5 33 2 - 8 0 Netherlands 20 8.2 3 .0 37 4 - 15. ,8 P Japan 20 16.7 4 .0 24 10 - 25. .1 R Germany U< 7.1 2 .5 35 3. .2 - 10 S Denmark 18 8.2 2 .6 32 6, .3 - 15. .8 U Denmark 20 6.5 2 .0 31 T O , .2 - 12, .6 T Louisi a n a 20 14.6 4 .7 32 6 .3 - 20 V Lou i s i a n a 20 14.0 5 .6 40 5 - 20 W Lou i s i a n a 20 12.8 5 .0 39 6 .3 - 20 X Lou i s i a n a 20 13.1 4 .4 34 4 - 20 Y Lou i s i a n a 20 15.2 4 .4 29 10 - 25 .1 Figure 4,9.3.2 The v a r i a t i o n i n l e a f area on the 13-10V77 (.2) f o r twenty s t r a i n s at random i n each., of four b l o c k s ; e a c h . s t r a i n represented by f i v e p l a n t s i n u l t i m a t e p l o t s ; u l t i - mate p l o t s l o c a t e d at random w i t h i n each, b l o c k , showing: a) The a r i t h m e t i c mean f o r each s t r a i n • b) The simple range by v e r t i c a l bar c) , ± one standard d e v i a t i o n from the mean by h o r i z o n t a l bars 30 r U.B.C. P l o t : l e a f a r e a 2 30 25 20 15 10 0 1- B C D E G H K L Crest. M O P R Neth. J a . Ger. 8 U T V W X Y Den. Louis. STRAIN .9 - Table 4 . 9 . 3 . 3 Contingency table and Chi-square values f o r average leaf area for twenty strains grown at U.B.C; sampled on the 2 0 - 7 - 7 7 . 2 Total Leaf Area (cm ) Strain 0 - 4 10 - 14 20 T o t a l 0 o 0 0 0 0 0 0 2 0 0 0 0 0 2 0 0 0 0 5 - 9 5 9 5 3 4 11 5 29 4 1 16 1 7 5 6 14 2 4 139 1 S U 14 14 14 15 18 12 15 8 14 10 . 18 15 17 20 26 17 15 24 312 15 - 19 19 18 20 10 17 12 . 19 20 20 20 21 6 22 15 13 8 9 21 11 302 ! 2 1 3 3 2 1 2 0 0 2 8 0 2 1 0 0 0 2 1 31 w 40 40 40 30 38 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 788 -Creston Netherlands Ja Ge Denmark -Louisiana- M O P R S U T V W X Actual x 2 = 2 5 7 . 1 8 * * Expected X 2 _ 0 5 ( 7 6 ) = 9 7 - 3 4 Table 4.9.3.4 Contingency table and Chi-square values f o r average l e a f area for twenty strains grown at U.B.C.; sampled on the 13-10-77. , 2 , Stra i n -Leaf Area (cm ) 0 - 4 2 1 1 5 - 9 15 11 12 1 0 - 1 4 3 8 6 0 4 / 1 5 - 1 9 0 0 1 0 0 0 20 - 0 Actual x 2 =317.05** Expected x " 0 > 0 5 ( 7 6 ) = 97 4 0 0 0 2 10 1 0 4 10 13 9 11 15 10 13 0 14 4 7 11 7 3 0 5 7 0 0 0 0 0 0 0 0 0 0 Total ' 20 20 20 10 2  7.34 18 0 0 0 0 1 12 0 1 0 0 0 0 0 18 20 20 18 20 20 20 20 18 18 -Creston Netherlands Ja Ge Denmark c n H K L M 0 P R S U --Louisiana V W X Total 0 1 0 0 0 1 0 27 0 175 0 8 1 9 9 9 12 10 125 8 50 20 20 20 20 20 20 382 94 The method by Williams et al_. (1964) f o r estimations of l e a f area proved to be a p r a c t i c a l and quick method of assessing l e a f area i n the f i e l d . Although the method i s designed to allow f o r l e a f shape, the greatest d i f f i c u l t y appeared when abnormally long leaves were encountered. 4.9.4 V a r i a t i o n i n P e t i o l e Length 4.9.4.1 M a t e r i a l s and Methods The same samples taken f o r l e a f area served f o r the measurement of p e t i o l e l ength. The p e t i o l e lengths were measured i n centimeters from the base of the p e t i o l e at the j u n c t i o n of the s t i p u l e s and p e t i o l e to the j u n c t i o n of the l e a f p e d i c e l s . 4.9.4.2 Observations and Results The F-test i n the a n a l y s i s of v a r i a t i o n suggest d i f f e r e n c e s between s t r a i n s and between dates f o r p e t i o l e length. The r e s u l t s of p e t i o l e length measurements are shown i n Table 4.9.4.1 and 4.9.4.2. I t i s again noteworthy that length decreases i n the f a l l . The L o u i s i a n a s t r a i n s again have the longer p e t i o l e s . Tables 4.9.4.3 and 4.9.4.4 r e l a t e l e a f area and p e t i o l e length f o r both f u l l y grown leaves and p e t i o l e s to l e a f area and p e t i o l e length f o r younger leaves and p e t i o l e s f o r two dates of observation. The c o r r e l a t i o n coef- f i c i e n t s i l l u s t r a t e that the d i f f e r e n c e s i n growth of leaves and p e t i o l e s are r e l a t i v e l y independent w i t h i n the intermediate form of white c l o v e r . 4.9.4.3 Di s c u s s i o n The work done by Denne (1966) and by Brougham (1966) traces the expan- si o n and h i s t o r y of area and length of leaves and p e t i o l e s i n the white c l o v e r canopy. Continual growth makes f o r u n r e l i a b l e measurements (or confounding) when samples are not c o r r e l a t e d w i t h age; the i n f o r m a t i o n i n Tables 4.9.4.3 and 4.9.4.4 supports these observations. Table -UK4.1 p e t i o l e length i n centimeters f o r i n d i v i d u a l p l a n t s i n twenty s t r a i n s grown i n a uniform nursery at U.B, .C, sampl ing date 20-7-77 r a i n Source No. p e t i o l e s per sample. Mean SD CM Range A Creston 40 21. .75 5.26 24 13-30 B Creston 40 23. .18 4.13 18 14-31 C Creston 40 20. .58 5.33 26 12-34 D Creston 30 20. .97 6.23 30 11-33 E Creston 38 20. .76 5.12 25 8-31 G Creston 40 20. .75 5.07 24 10-30 H Creston 40 22. .03 5.46 25 8-31 K Creston 40 22. .25 5.25 24 12-35 L Creston 40 23. .18 5.53 24 15-34 M Netherlands 40 17. .75 4.68 26 9-26 0 Netherlands 40 19. .88 4.36 22 13-28 P Japan 40 23. .48 6.50 28 14-40 R Germany 40 20. .33 5.44 27 11-33 S Denmark 40 20, .15 4.69 23 10-30 U Denmark 40 19, .83 5.99 30 9-34 T L o u i s i a n a 40 23, .28 4.91 21 15-34 U Louisi a n a 40 21, .30 5.89 28 9-35 W Louisiana 40 21, .63 5.84 27 13-34 X Louisi a n a 40 22 .75 5.37 24 11-34 Y Louisi a n a 40 23, .50 5.46 23 13-36 96 Table"4.9.4.2.'' Avg. p e t i o l e length i n centimeters f o r i n d i v i d u a l p l a n t s i n twenty s t r a i n s grown i n a uniform nursery at U.B.C, sampling date 13-10-77 Xc. petioles' S t r a i n Source p e r sample- Mean SD CV% Range A Creston 20 14.45 3.41 24 7-21 B Creston 20 13.85 4.18 30 6-21 C Creston 20 15.78 5.24 33 7-25 D Creston 10 14.50 2.80 19 11-20 E Creston 18 11.40 4.60 40 4-21 G Creston 20 13.95 4.11 29 6-22 H Creston 20 16.85 3.76 22 10-23 K Creston 18 15.78 4.35 28 9-24 L Creston 20 13.55 3.38 25 7-20 M Netherlands 20 10.40 3.39 33 5-17 0 Netherlands 20 13.55 4.89 36 5-23 P Japan 20 20.05 5.75 29 12-29 R Germany 18 12.39 4.80 39 6-24 S Denmark 18 13.39 2.57 19 9-19 U Denmark 20 11.00 3.34 30 7-19 T L o u i s i a n a 20 17.90 5.19 29 11-25 U Louisiana 20 17.90 5.59 31 10-28 W Loui s i a n a 20 17.85 5.71 32 8-28 X L o u i s i a n a 20 18.30 6.61 36 7-29 Y Loui s i a n a 20 21.30 5.03 24 13-30 Table 4.9.4.3 R e l a t i o n s h i p of l e a f area to p e t i o l e l e ngth; measurements grown i n a uniform nursery at S t r a i n O r i g i n _ A Creston Y B Creston Y C Creston Y D Creston Y E Creston Y G Creston Y H Creston Y K Creston Y L Creston Y M Netherlands Y 0 Netherlands Y P Japan Y R Germany Y • S Denmark Y = U Denmark Y = T L o u i s i a n a Y = V Lo u i s i a n a Y = W Louis i a n a Y : X Lo u i s i a n a Y = Y Lo u i s i a n a Y = F u l l y grown leaves and p e t i o l e s L i near Regression Equation C o r r e l a t i o n C o e f f i c i e n t = 19.86 + 0.29X r = 0.34 = 24.21 + 0.08X r = 0.09 = 14.62 + 0.59X r = 0.30 = 16.12 + 0.49X r = 0.57 = 21.95 + 0.12X r = 0.13 = 23.32 + 0.10X r = 0.14 • 20.04 + 0.39X r = 0.29 21.66 + 0.25X r = 0.25 17.39 + 0.42X r = 0.21 16.40 + 0.47X r = 0.77** 26.32 + 0.14X r = 0.17 17.43 + 0.54X r = 0.63 18.22 + 0.38X r = 0.35 9.70 + 0.76X r = 0.75* 15.84 + 0.68X r = 0.55 22.88 + 0.11X r = 0.11 24.46 + 0.11X r = 0.09 23.64 + 0.12X r = 0.13 28.03 - 0.002X r = -0.002 taken on 20-7-77 f o r twenty s t r a i n s U.B.C. Younger leaves and p e t i o l e s L i n e a r Regression C o r r e l a t i o n Equation Y = 10.89 + 0.51X Y = 22.32 - 0.09X Y = 8.14 + 0.61X y = Y = 8.39 + 0.54X Y = 18.07 + 0.01X Y = 8.46 + 0.64X Y = 9.55 + 0.62X Y = 18.04 + 0.11 Y = 10.49 + 0.51 Y = 15.92 + 0.01 Y = 20.64 - 0.01 Y = 16.21 + 0.11 Y = 16.09 + 0.12 Y = 10.78 + 0.40 Y = 15.19 + 0.35 Y = 23.59 - 0.28 Y = 12.89 + 0.45 Y = 9.77 + 0.60 Y = 26.04 - 0.58 C o e f f i c i e n t r = 0.68* r = -0.07 r = 0.79** r = r = 0.58 r = 0.01 r = 0.60 r = 0.69* r = 0.18 r = 0.34 r = 0.04 r = -0.01 r = 0.18 r = 0.42 r = 0.55 r = 0.50 r = 0.33 r = 0.64* r = 0.52 r = 0.39 Leaf area - X; P e t i o l e length - Y; Sample s i z e - 10 r.05(8) = 0.6319* r.01(8) = 0.7646** observations per treatment Table 4.9. 4.4 R e l a t i o n s h i p o f l e a f area to p e t i o l e length; measurements taken the 13-10-77 f o r twenty s t r a i n s grown i n a uniform nursery at U.B.C. F u l l y grown leaves and p e t i o l e s Younger leaves and p e t i o l e s S t r a i n O r i g i n Regression equation C o r r e l a t i o n C o e f f i c i e n t Regression equation C o r r e l a t i o n A Creston Y = 9.60 + 0.92X r = 0.72* Y = 5.18 + 0.96X v j u c t i n — L C 1 1 L r = 0.80** B Creston Y = 5.61 + 1.37X r = 0.77** Y = 3.84 + 0.84X r = 0.71* C Creston Y = 13.61 + 0.59X r = 0.41 Y = 9.25 + 0.34X r = 0.27 D Creston E Creston Y = 4.75 + 1.39X r = 0.77** Y = 3.25 + 0.94X r = 0.76* G Creston Y = 8.36 + 0.94X r = 0.74* Y = 4.57 + 0.89X r = 0.55 H Creston Y = 12.53 + 0.75X r = 0.49 Y = 13.50 + 0.05X r = 0.50 K Creston Y = 7.30 + 1.25X r = 0.71 Y = 11.41 + 0.30X r = 0.24 L Creston Y = 7.87 + 1.03X r = 0.84** Y = 4.42 + 1.02X r = 0.69* M Netherlands Y = 6.72 + 1.30X r = 0.65* Y = 3.40 + 1.08X r = 0.81** 0 Netherlands Y = 9.22 + 0.75X r = 0.60 Y = 0.15 + 1.40X r = 0.71* P Japan Y = 25.25 - 0.04X r = -0.05 Y = 6.76 + 0.47X r = 0.41 R Germany Y = 4.95 + 1.42X r = 0.81** Y = 4.28 + 0.75X r = 0.90** S Denmark Y = 15.47 - 0.04X r = -0.06 Y = 8.91 + 0.33X r = 0.52 U Denmark Y = 9.00 + 0.61X r = 0.46 Y = 8.79 - 0.01X r = -0.02 T Lo u i s i a n a Y = 13.73 + 0.57X r = 0.77** Y = 16.97 - 0.16X r = -0.15 V Lo u i s i a n a Y = 10.82 + 0.79X r = 0.60 Y = 13.93 + 0.08X r = 0.12 w L o u i s i a n a Y = 20.49 + 0.10X r = 0.08 Y = 14.72 - 0.05X r = -0.08 X Lo u i s i a n a Y = 12.90 + 0.74X r = 0.43 Y = 7.69 + 0.51X r = 0.43 Y Lo u i s i a n a Y = 20.46 + 0.38X r = 0.21 Y = 16.56 + 0.05X r = 0.07 Leaf area - X; P e t i o l e length - Y; Sample s i z e - 10 r.05(8) = .6319* r.01(8) = .7646** observations per treatment 99 4.9.5 V a r i a t i o n i n Leaf Shape and Markings 4.9.5.1 M a t e r i a l s and Methods Observation of l e a f shapes and markings took place i n the l a t t e r p a r t of J u l y 1977. Leaves were c l a s s i f i e d according to 4 shape categories (Oval, Round, Heart-shaped, Round i n c i s e d ) . The i n v e r t e d "V" marks were grouped as present or absent as used by Cahn and Harper (1976). The c l a s s i f i c a t i o n of the i n v e r t e d "V" mark was grouped i n t o three c a t e g o r i e s : broken and f a i n t , complete and f a i n t , l a r ge and i n t e n s e . The presence and absence of antho- cyanin f l e c k s were noted as per Carnahan et a l . (1955) and C o r k i l l (1971). 4.9.5.2 Observations and Results Leaf shape:- Observations on l e a f shape f o r the twenty d i f f e r e n t s t r a i n s i s given i n Table 4.9:5.1:' Examination of the d i s t r i b u t i o n suggests that round leaves and round i n c i s e d leaves are the most abundant. Inverted "V" mark:- The two methods used and data assessment o f the studies on the i n v e r t e d "V" mark are given i n Tables 4.9.5.2 and 4.9.5.3. The F-test i n the a n a l y s i s of v a r i a t i o n suggests s i g n i f i c a n c e between s t r a i n but not among block means. In Table 4.9.5.2 the r a t i o of i n v e r t e d "V" marks to no "V" marks i s given; the Creston and Netherlands s t r a i n s , had r a t i o s of 3:1 or 4:1 w i t h l e s s intense marks, while the Japanese, German and L o u i s i a n a s t r a i n s had r a t i o s from 19:1. to 20:0. The two Denmark s t r a i n s at r a t i o s of 12:1 were intermediate. Table 4.9.5.3 i s a contingency t a b l e d i s p l a y i n g l e a f markings i n four c a t e g o r i e s . The d i s t r i b u t i o n s are o b v i o u s l y not random. Anthocyanin f l e c k i n g : - The r a t i o s f o r the presence and absence of anthocyanin f l e c k i n g are given i n Table 4.9.5.4. There appears to be a d i f f e r e n c e between s t r a i n s , but i t i s not s t r o n g l y i n d i c a t e d Table 4.9.5.1 Contingency t a b l e and Chi-square values f o r white c l o v e r l e a f shapes on twenty s t r a i n s grown i n a uniform nursery at U.B.C. S t r a i n Shape A B C D E G H K L M 0 P R S U T V W X Y Total 1 1 0 0 0 0 0 0 0 0 1 0 6 0 0 0 2 0 1 0 1 12 2 6 4 6 11 8 2 3 7 7 4 6 2 7 9 6 6 4 3 5 10 116 3 2 5 1 0 1 4 7 2 2 4 3 7 3 1 3 0 1 0 2 0 48 4 6 6 8 4 5 9 5 5 6 6 6 0 4 4 6 7 10 11 8 4 120 T o t a l 15 15 15 15 14 15 15 14 15 15 15 15 14 14 15 15 15 15 15 15 296 Ac t u a l 2 X = 136 .13 ** 2 Expected x .05(57) = 75. .61 Leaf Shape 1 = Oval Ovate or obovate 2 = Round O r b i c u l a t e 3 = Heart shaped Obcordate 4 = Round i n c i s e d O r b i c u l a t e notched 101 Table 4.9.5.2 Ratio of water marks to no water marks f o r twenty s t r a i n s of white c l o v e r grown at U.B.C. S t r a i n A B C D E G H K L M 0 P R S U T V W X Y O r i g i n Creston Creston Creston Creston Creston Creston Creston Creston Creston Netherlands Netherlands Japan Germany Denmark Denmark Louisi a n a L o u i s i a n a L o u i s i a n a L o u i s i a n a L o u i s i a n a Water mark 15 18 16 12 16 16 14 17 13 18 12 20 19 18 14 19 20 20 20 20 No water mark 5 2 4 3 3 4 6 3 7 2 8 0 1 2 6 1 0 0 0 0 Pooled f- 4:1 3:1 20:0 19:1 12:1 h 19:1 Table 4.9.5.3 Contingency table and Chi-square values for four classes of l e a f markings i n 20 str a i n s o f white clove r grown i n a uniform nursery at U.B.C. Tot a l No mark 5 2 4 3 3 4 6 3 7 2 8 0 1 2 6 1 0 0 0 0 57 Broken and f a i n t 5 6 3 5 3 4 4 8 3 5 2 0 2 8 4 0 0 0 0 0 62 Complete and f a i n t 7 4 9 2 8 1 2 6 5 5 7 4 3 5 7 3 4 2 1 2 1 97 Large and intense 3 8 4 5 5 0 4 4 5 6 6 17 12 3 7 15 18 19 18 19 178 Total 20 20 20 15 19 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 394 Creston Netherlands Ja Ge Denmark Louisiana A B C D E G H K L M 0 P R S U T V W X Y 2 2 Actual x = 156.64 Expected x 0 5 ( 5 7 ) = 75.61 103 Table 4.9.5.4 Ratio of anthocyanin f l e c k i n g to no f l e c k i n g f o r twenty s t r a i n s of white c l o v e r grown at U.B.C. S t r a i n A B C D E G H K L M 0 P R S U T V W X Y O r i g i n Creston Creston Creston Creston Creston Creston Creston Creston Creston Netherlands Netherlands Japan Germany Denmark Denmark Louisi a n a L o u i s i a n a L o u i s i a n a L o u i s i a n a L o u i s i a n a F l e c k i n g 12 4 6 4 7 6 9 9 6- 10 10 2 8 4 7 5 5 4 No F l e c k i n g .8 16 14 11 12 14 11 11 14 10 10 18 12 16 13 15 15 16 12 17 Pooled 1:2 h 1:1 1:9. 2:3 1:3 1:3 104 (Table 4.9.5.5). The presence or absence of anthocyanin l e a f f l e c k s i s only a random a s s o c i a t i o n w i t h the presence or absence of the i n v e r t e d "V" l e a f mark (Table 4.9.5.6). 4.9.5.3 Discuss i o n Leaf shape was not an easy parameter to study because of the m u l t i - p l i c i t y of intermediate shapes. However i t i s nonetheless an important b i o l o g i c a l one s i n c e leaves are the primary organs of photosynthesis. On the other hand the i n v e r t e d "V" mark and anthocyanin f l e c k i n g appear to be l e s s s i g n i f i c a n t b i o l o g i c a l l y . They are so d i f f i c u l t to c l a s s i f y that "presence" or "absence" were the only r e l i a b l e c a t e g o r i e s . They are none- th e l e s s u s e f u l markings f o r f i e l d i d e n t i f i c a t i o n . 4.9.6 V a r i a t i o n i n P l a n t Height 4.9.6.1 M a t e r i a l s and Methods Pla n t height was measured i n l a t e September by p l a c i n g a r u l e r i n the centre of the p l a n t and noting the height of the canopy. I n d i v i d u a l leaves that were h e l d higher than the canopy were ignored. 4.9.6.2 Observations and Results P l a n t height measurements are found i n Table 4.9.6.1 and i n Figure 4.9.6.1. Creston s t r a i n s show a wide range of v a r i a t i o n , although the Lo u i s i a n a s t r a i n s were c o n s i s t e n t l y the t a l l e s t . The F-tests i n the a n a l y s i s of v a r i a t i o n suggested that the d i f f e r e n c e between s t r a i n means were h i g h l y s i g n i f i c a n t . P l a n t height measurements f o l l o w c l o s e to those of p e t i o l e length. 4.9.6.3 Di s c u s s i o n Only one measurement of p l a n t height was taken. This was about two weeks p r i o r to the p e t i o l e length measurements but again the Creston s t r a i n s are intermediate while the L o u i s i a n a s t r a i n s are t a l l f o r t h i s time of year. Table 4 . 9 . 5 . 5 Presence Contingency t a b l e and Chi-square values f o r anthocyanin f l e c k i n g i n 20 s t r a i n s of white c l o v e r grown i n a uniform nursery at U.B.C. S t r a i n A B C D E G H K L M O P R S U T V W . X Y T o t a l ' " 8 4 6 4 7 6 9 9 6 10 10 2 8 4 7 5 5 4 8 3 129 Absence 12 16 14 11 12 14 11 11 14 10 10 18; 12 16 13 15 15 16 12 17 265 T o t a l 20 20 20 15 19 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 394 2 2 A c t u a l x = 2 3 . 4 1 \ Expected x 0 5 ( 1 9 ) " 3 ° " 1 4 o / 106 Table 4.9.5.6 Contingency t a b l e f o r white c l o v e r l e a f markings and anthocyanin l e a f f l e c k i n g on twenty s t r a i n s grown i n a uniform nursery at U.B.C. Anthocyanin Inverted "V" Leaf Mark f l e c k i n g Absent Present T o t a l Absent 36 229 265 (38.34) (226.66) Present 21 108 129 (18.66) (110.34) T o t a l 57 337 394 Expected values i n brackets, A c t u a l X 2 = 0.50 Expected X 2 .05(1) =3.84 107 Table 4.9.6.1 Plant height i n centimeters f o r i n d i v i d u a l p l a n t s i n twenty s t r a i n s grown i n a uniform nursery at U.B.C. No. p l a n t s S t r a i n Source per samples Mean SD CV% Range A Creston 20 17.0 3.7 22 1 2 - 2 5 B Creston 20 16.0 3.5 22 9 - 2 2 C Creston 20 16.6 5.1 31 6 - 2 5 D Creston 15 15.7 2.4 15 1 2 — 21 E Creston 19 14.0 4.3 31 5 - 2 1 G Creston 20 14.6 3.5 24 6 - 1 9 H Creston 20 16.9 3.5 21 11 - 22 K Creston 20 17.5 2.7 15 12 - 22 L Creston 20 14.7 5.0 34 8 - 3 0 M Netherlands 20 11.5 2.9 25 7 - 1 7 0 Netherlands 20 13.8 2.9 21 6 - 1 8 P Japan 20 21.6 5.5 25 1 1 - 3 1 R Germany 20 13.3 4.2 32 5 - 2 3 S Denmark 20 13.2 3.2 .24 6 - 1 9 U Denmark 20 12.9 3.8 29 4 - 1 8 T Loui s i a n a 20 22.9 2.6 11 19 - 28 V Loui s i a n a 20 23.8 4.1 17 14 - 30 W Loui s i a n a 20 ' 22.7 4.4 19 9 - 2 9 X L o u i s i a n a 20 21.4 5.3 25 7 - 2 9 Y Lo u i s i a n a 20 23.3 4.7 20 9 - 3 3 Figure h.9.6.1 The v a r i a t i o n i n p l a n t height f o r twenty s t r a i n s at random i n each, of four b l o c k s ; each, s t r a i n represented by f i v e plants:, i n u l t i m a t e p l o t s ; u l t i m a t e p l o t s l o c a t e d at random w i t h i n each, b l o c k , showing: a) The a r i t h m e t i c mean f o r each, s t r a i n • b) The simple range by v e r t i c a l bar c) ± one standard d e v i a t i o n from the mean by h o r i z o n t a l bars 3 0 2 5 2oy 1 5 1 0 H K M Creston Neth. P i Ja. Ger. R i S u Den W Louis. Y i STRAIN 109 4.9.7 V a r i a t i o n i n Cyanogenesis 4.9.7.1 M a t e r i a l s and Methods In the l a t t e r h a l f of September, a l l p l a n t s were sampled f o r cyano- genesis. The method used was by means of the p i c r a t e paper t e s t , using a set of standards. P i c r a t e paper was prepared as o u t l i n e d by Nowosad and MacVicar (1940) and stored i n an a i r t i g h t c o n t a i n e r . A standard cyanide s o l u t i o n was prepared by d i s s o l v i n g 241 mg' of potassium cyanide i n one l i t r e of d i s t i l l e d water. At 09:00 hours, samples of about 150 mg of.... ' f r e s h p l a n t t i s s u e from each p l a n t were placed i n 10 mm x 120 mm.test tubes, samples were b r u i s e d and 10 drops of chloroform added. A s t r i p of p i c r a t e paper was placed i n the tube and h e l d i n place by a rubber stopper. A set of standards were made up by p l a c i n g a range of measured q u a n t i t i e s of the cyanide s o l u t i o n i n t e s t tubes to give a range of values from 0 ug to 80 . Pg- A s t r i p of p i c r a t e paper was placed i n each of these tubes and h e l d i n place w i t h a rubber stopper. A l l samples were incubated at 30°C f o r twenty hours. P i c r a t e papers were then compared with the standards and a r e l a t i v e r a t i n g of the l e v e l of r e a c t i o n f o r each p l a n t was e s t a b l i s h e d . 4.9.7.2 Observations and Results There were some v a r i a t i o n s i n HCN l e v e l s from block to block because only one block could be done on a given day. The d i f f e r e n c e s between s t r a i n s were very marked. A l l Creston and Netherlands s t r a i n s gave a negative r e a c t i o n w h i le a l l L o u i s i a n a s t r a i n s gave a h i g h l y p o s i t i v e r e a c t i o n . The Japanese s t r a i n Tohoku was negative while one Danish s t r a i n Pajberg M i l k a and a German s t r a i n K i v i gave o c c a s i o n a l p o s i t i v e r e a c t i o n s . 4.9.7.3 Di s c u s s i o n The method of making a set of standards gave a reasonable approximation of the amount of r e l e a s e by each p l a n t of hydrogen cyanide. For the purpose 110 of t h i s study, p o s i t i v e or negative r e a c t i o n s were s u f f i c i e n t . 4.9.8 V a r i a t i o n i n Pla n t Weight 4.9.8.1 M a t e r i a l s and Methods On two dates, August 18th and October 19th, growth was cut; the m a t e r i a l was thoroughly d r i e d i n a pot hole d r i e r . Weights were recorded i n gms of a i r - d r y m a t e r i a l . 4.9.8.2 Observations and Results The data obtained from the sampling on the two dates are given i n Tables 4.9.8.1 and 4.9.8.2 and Figures 4.9.8.1 and 4.9.8,2. The F-test was i n s i g n i f i c a n t f o r weight between s t r a i n s f o r the f i r s t date (August 18th) and t h i s i s i l l u s t r a t e d i n Figure 4.9.8.1. The second date (October 19th) shows the lower weights f o r a l l s t r a i n s but i t i s noteworthy that the Louisi a n a s t r a i n s are heavier producers i n l a t e summer and f a l l than the Creston s t r a i n s ; l e a f area responds l i k e w i s e . 4.9.8.3 Discuss i o n There appears to be a r e l a t i o n s h i p between l e a f area and p l a n t weight, however, i t i s noteworthy that s m a l l e r leaved p l a n t s are more p e r s i s t e n t . 4.10 V a r i a t i o n W ithin and Between Clones 4.10.1 Comment on T r i a l Layout On the 1st September 1976 p l a n t s were c o l l e c t e d from four areas i n each of f i v e f i e l d s i n the Creston area. The p l a n t s o r i g i n a t e d from p l a n t - ings made i n 1975 and 1976 and are designated by the name of the farmer owning a f i e l d , and by year of p l a n t i n g . These p l a n t s were grown i n the greenhouse at U.B.C. and i n December 1976 c u t t i n g s were made from i n d i v i d u a l p l a n t s . Three c u t t i n g s from a s i n g l e runner made up a set of three genet- i c a l l y " i d e n t i c a l " p l a n t s . Each set was not n e c e s s a r i l y r e l a t e d to the Table 4.9.8.1 111 I n d i v i d u a l p l a n t weights i n grams f o r twenty s t r a i n s grown i n a uniform nursery at U.B.C. Sampling date 18-8-77(1) No-. •• p l a n t s S t r a i n Source ' per sample,,; Mean SD CV% Range A Creston 20 409 115 28 282 - 772 B . Creston 20 492 146 30 270 - 961 C Creston 20 419 81 19 282 - 664 D Creston 15 421 79 19 289 - 567 E Creston 19/ 405 89 22 255 - 559 G Creston 20 435 120 28 300 - 748 H Creston 20 476 132 28 313 - 838 K Creston 20 406 81 20 280 - 574 L Creston 20 384 91 24 223 - 548 M Netherlands 20 478 140 29 257 - 817 0 Netherlands 20 392 91 23 241 - 577 P Japan 20 424 140 33 235 - 803 R Germany 20 328 126 38 158 - 622 S Denmark 20 430 128 30 259 - 819 U Denmark 20 379 120 32 181 - 622 T Louisiana 20 374 126 34 183 - 630 V Lo u i s i a n a 20 434 131 30 260 - 666 W Louisi a n a 20 376 95 25 271 - 584 X Louisi a n a 20 445 173 39 241 - 975 Y Lou i s i a n a 20 409 110 27 ; • 273 - 684 Figure 4.9.8.1 The v a r i a t i o n i n standing crop weight from the harvest on the 18-8-77 ( l ) of white c l o v e r p l a n t s from the twenty- s t r a i n s at random i n each of four blocks each s t r a i n represented hy f i v e p l a n t s i n u l t i m a t e p l o t s ; u l t i m a t e p l o t s l o - cated at random w i t h i n each b l o c k , show- i n g : a) The a r i t h m e t i c mean f o r each s t r a i n b) The simple range by v e r t i c a l bar c) - one standard d e v i a t i o n from the mean by h o r i z o n t a l bars 1 0 0 0 . 9 0 0 8 0 0 7 0 0 \ 6 0 0 h E O ) •- 500 r 4 0 0 - 3 0 0 - 2 0 0 - 150- U a C . plot: weight 0) L _ A B C D E G H K L M O P i R i S T i Creston Neth. Ja. Ger. Den. V W X Louis. Y S T R A I N 113 Table 4.9.8.2 I n d i v i d u a l p l a n t i n a uniform nurs weights i n grams f o r twenty ery at U.B.C. Sampling date s t r a i n s grown 19-10-77(2) S t r a i n No. p l a n t s Mean SD CV% Source per sample ' Range A Creston 10 30 25 83 14 - 93 B Creston 10 31 18 58 8 - 52 C Creston 10 34 19 56 6 - 72 D Creston 5 37 20 54 21 - 71 E Creston ,9 19 19 100 5 - 64 G Creston 10 41 33 80 6 - 108 H Creston 10 46 22 48 23 - 77 K Creston 19 40 21 53 9 - 68 L Creston 1.0 25 18 72 4 - 72 M Netherlands 10 35 22 63 7 - 82 0 Netherlands 10 40 28 70 3 - 73 P Japan 10 85 30 35 37 - 148 R Germany :.9 50 22 44 9 - 79 S Denmark 19 32 20 63 6 - 64 U Denmark 10 4:3 29 "67- - 34 - 86 T Louisiana;. 10 105 43 41 66 - 206 'V. Louisiana 10 96 40 42 25 - 125 W Louisiana 10 85 47 55 10 - 186 X Louisi a n a 10 91 22 24 67 - 126 Y Louisi a n a 10 113 19 17 75 - 135 F i g u r e 4.9.8.2 The v a r i a t i o n i n standing crop weight from harvest on the 19-10-77 (2) of white c l o v e r p l a n t s from twenty s t r a i n s at random i n each of four b l o c k s ; each s t r a i n represented by f i v e p l a n t s i n ul t i m a t e p l o t s ; u l t i m a t e p l o t s l o c a t e d at random w i t h i n each b l o c k , showing: a) The a r i t h m e t i c mean f o r each s t r a i n b) The simple range by v e r t i c a l bar c) ± one standard d e v i a t i o n from the mean by h o r i z o n t a l bars 2 2 0 r 2 0 0 ^ 180r 160h 140r 120 O) 1001 801 60 40 2 0 ) - U.B.C. plot: weight (2) H L M O P i R Creston Neth. Ja. Ger. s u I I Den. T V W X Louis . STRAIN 115 other sets from the same area of the f i e l d . The c u t t i n g s were p l a n t e d i n u n s t e r i l i z e d Creston s o i l and placed i n the m i s t i n g chamber. On A p r i l 1st, 1977, these p l a n t s were moved to the c o l d frames f o r hardening. On June 14th the p l a n t s were set out i n Totem F i e l d , U.B.C. i n a randomized design with four b l o c k s . The main reason f o r the c l o n a l propagation was to o b t a i n p l a n t s that were g e n e t i c a l l y i d e n t i c a l so that we could compare the v a r i a t i o n caused by non-genetic f a c t o r s such as v a r i a t i o n i n s o i l , root damage and other u n i d e n t i f i a b l e f a c t o r s . 4.10.2 V a r i a t i o n i n Leaf Area 4.10.2.1 M a t e r i a l s and Methods Two samples were taken from each p l a n t on each of two dates ( J u l y 20th and October 20th). A sample c o n s i s t e d of a t r i f o l i a t e l e a f and i t s p e t i o l e . One sample was taken from the t h i r d open l e a f from the end of a s t o l o n (young l e a f ) . The other sample was taken from the centre of the p l a n t . Leaf area was estimated i n square centimeters by use of the.method o u t l i n e d by Williams et a l . (1964). 4.10.2.0 Observations and Results The r e s u l t s -of these observations are l i s t e d i n Tables 4.10.2.1 and 4.10.2.2. and Figures 4.10.2.1 and 4.10.2.2. Considerable m o d i f i c a t i o n i n l e a f area i s evident from the l a t e p l a n t i n g . The F-test i n the a n a l y s i s of v a r i a t i o n suggested d i f f e r e n c e s between s t r a i n s and between the two sampling dates; p l a n t s of the 1976 p l a n t i n g showed a small r e d u c t i o n i n mean l e a f area. Tables 4.10.2.3 and 4.10.2.4 show the v a r i a b i l i t y w i t h i n each clone. This v a r i a b i l i t y i s a s s o c i a t e d mainly w i t h e r r o r i n sampling and other non- i n h e r i t e d f a c t o r s . I f we compare the average c o e f f i c i e n t s of v a r i a t i o n to 116 Table 4.10.2.1 Area representation of individual leaves (in square centimeters) for five strains of white clover grown in a uniform nursery at U.B.C, sampled 20-7-77(1). ~ain Source 2 Mean(cm ) ' SD(cm 2) c n Rahj ge 1 Staples 1975 7.68 1.65 21 4 - 12.6 2 Ogilvie 1975 7.88 2.45 31 5 - 15.8 3 Mulligan 1976 5.79 1.51 26 3.2 - 10 4 Eastman 1975 7.14 2.85 40 2 - 12.6 5 Eastman 1976 6.94 2.65 38 3.2 - 15.8 Number of leaves for each treatment - 48 Table 4.10.2.2 Area representation of individual leaves (in square centimeters) for five strains of white clover grown in a uniform nursery at U.B.C., sampled 20-10-77(2). Strain Source 2 Mean(cm ) SD(cm2) cv% Range 1 Staples 1975 7.10 2.13 30 2.5 - 12 .6 2 Ogilvie 1975 7.30 4.10 55 1.6 - 20 3 Mulligan 1976 6.81 2.6 38 2.5 - 12 .6 4 Eastman 1975 6.59 2.8 42 2 - 12 .6 5 Eastman 1976 5.01 1.62 32 1.3 - 10 Number of leaves for each treatment - 48 Figure 4.10.2.1 The v a r i a t i o n i n l e a f area on the 20-7-77 ( l ) ; p l a n t s were grown from c u t t i n g s and e s t a b l i s h e d i n a uniform nursery. The f i v e s t r a i n s are at random i n each of four b l o c k s ; each s t r a i n i s represented by nine p l a n t s i n the u l t i m a t e p l o t s ; the u l t i m a t e p l o t s are l o c a t e d at ran- dom w i t h i n each b l o c k , showing: a) The a r i t h m e t i c mean f o r each s t r a i n • b) The simple range by v e r t i c a l bar c) t o n e standard d e v i a t i o n from the mean by h o r i z o n t a l bars U.B.C. Clones: Leaf Area 0) 1 1 7 I*. E 8 2 0 15 lOf- + 3 STRAIN Figure 4.10.2.2. The v a r i a t i o n i n l e a f area on the 20-10-77 (2 ) ; p l a n t s were grown from c u t t i n g s and e s t a b l i s h e d i n a uniform nursery. The f i v e s t r a i n s are at random i n each of four b l o c k s ; each s t r a i n i s represented by nine p l a n t s i n the u l t i m a t e p l o t s ; the u l t i m a t e p l o t s are l o c a t e d at ran- dom w i t h each bl o c k . a) The a r i t h m e t i c mean f o r each s t r a i n • b) The simple range by v e r t i c a l bar c) ± one standard d e v i a t i o n from the mean by h o r i z o n t a l bars U .B.C. C l o n e s : L e a f A r e a (2) 20r 15 10 oL 1 3 S T R A I N 119 Table 4.10.2.5 Mean leaf area v a r i a b i l i t y within clones of f i v e strains of white clover grown i n a uniform nursery at U . B . C ; three plants i n each clone, eight clones i n each s t r a i n ; average of the mean and the standard deviation c o e f f i c i e n t for eight clones i n each s t r a i n ; c o l l e c t i o n date 20-7-77. a - old leaf b - young leaf Strain Source Mean SD CV% 1 Staples 1975 a - 7.86 1.06 13 b - 7.49 1.48 20 2 Ogilvie 1975 a - 8.06 1.46 18 b -7.69 1.75 23 3. Mulligan 1976 a - 5.74 0.78 14 b - 5.84 1.56 27 4 Eastman 1975 a - 8.10. 2.19 27 b - 6.27 1.21 19 5 Eastman 1976 a - 6.31 1.23 19 b -7.57 1.32 17 120 Table 4.10.2.4 Mean leaf area variability within clones of five strains of white clover grown in a uniform nursery at U.B.C; three plants in each clone, eight clones in each strain; average of the mean and the standard deviation for eight clones in each strain; collection date 20-10-77. a - old leaf b - young leaf Strain Source Mean SD CV! 1 Staples 1975 a - 6.88 1.33 19 b - 7.33 1.34 18 2 • Ogilvie 1975 a - 6.41 1.65 26 b - 8.20 1.96 24 3 Mulligan 1976 a - 6.02 1.01 17 b - 7.59 1.16 15 4 Eastman 1975 a - 6.50 1.34 21 b - 6.86 1.29 19 5 Eastman 1976 a - 5.05 1.02 20 b - 4.98 1.68 34 121 to those i n Tables 4.10.2.1, 4.10.2.2, 4.9.3.1 and 4.9.3.2 we see that about 30-60 percent v a r i a t i o n can be a t t r i b u t e d to g enetic f a c t o r s . 4.10.3 V a r i a t i o n i n P e t i o l e Length 4.10.3.1 M a t e r i a l s and Methods The same samples taken f o r l e a f area a l s o served f o r p e t i o l e length measurements. P e t i o l e lengths were measured i n centimeters from the base of the p e t i o l e at the j u n c t i o n of the s t i p u l e s and p e t i o l e to the j u n c t i o n of the l e a f p e d i c e l s . 4.10.3.2 Observations and Results The r e s u l t s of observations on p e t i o l e length are given i n Tables 4.10.3.1 and 4.10.3.2. The F - t e s t i n the a n a l y s i s of v a r i a t i o n suggests a d i f f e r e n c e between s t r a i n s both f o r young p e t i o l e s and o l d p e t i o l e s on both dates of observation ( J u l y 20th and October 20th) . Table 4.10.3.3, the r e l a t i o n s h i p of l e a f area to p e t i o l e length f o r the two sampling dates. S t r a i n 4 i s the only s t r a i n showing a h i g h l y s i g n i f i c a n t r e l a t i o n s h i p of l e a f area to p e t i o l e length f o r both dates. 4.10.4 V a r i a t i o n i n P l a n t Weight 4.10.4.1 M a t e r i a l s and Methods On September 1st a l l p l a n t s were harvested, d r i e d i n the pot hole d r i e r , and weighed. 4.10.4.2 Observations and Results The F - t e s t i n the a n a l y s i s of v a r i a t i o n suggests d i f f e r e n c e s between s t r a i n s . The a i r - d r y weights of m a t e r i a l harvested are presented i n Table 4.10.4.1 and F i gure 4.10.4.1. S t r a i n three only shows any abnormal y i e l d . Table 4.10.4.2 gives the average v a r i a t i o n that e x i s t s between p l a n t s w i t h i n a clone f o r the f i v e s t r a i n s and comparing the c o e f f i c i e n t s of v a r i a t i o n to those i n Tables 4.10.4.1 and 4.9.8.1 we see that 75 to 30 percent v a r i a t i o n i n p l a n t weight i s due to genetic f a c t o r s . 122 Table 4.10.3.1 P e t i o l e length i n centimeters f o r f i v e s t r a i n s of white c l o v e r grown i n a uniform nursery at U.B.C, sampled 20-7-77. S t r a i n Source Mean S.D. CV % Range 1 Staples 1975 13.71 3.68 27 7 - 2 1 2 O g i l v i e 1975 12.98 4.26 33 6 - 2 1 3 M u l l i g a n 1976 8.94 2.49 28 5 - 1 5 4 Eastman 1975 13.48 3.93 29 6 - 22 5 Eastman 1976 11.42 3.44 30 6 - 2 0 Number of samples f o r each treatment - 48. Table 4.10.3.2 P e t i o l e length i n centimeters f o r f i v e s t r a i n s o f white c l o v e r grown i n a uniform nursery at U.B.C, sampled 20-10-77. S t r a i n Source Mean S, ,D. CV % Range 1 Staples 1975 15.58 3, .49 22 8 - 2 3 2 O g i l v i e 1975 14.42 5, .13 36 6 - 2 5 3 M u l l i g a n 1976 13.31 3. .63 27 6 - 1 9 4 Eastman 1975 13.42 4. .88 36 5 - 2 2 5 Eastman 1976 11.54 3. .46 30 4 - 1 8 Number of samples f o r each treatment - 48. Table 4.10.3.3 Line a r r e g r e s s i o n equations and c o r r e l a t i o n c o e f f i c i e n t s f o r white c l o v e r c l o n a l m a t e r i a l f o r two dates grown i n a uniform nursery at U.B.C. P l a n t s were v e g e t a t i v e l y propagated from m a t e r i a l of Creston o r i g F i v e treatments, each treatment contained ei g h t groups w i t h three g e n e t i c a l l y i d e n t i c a l p l a n t s i n each group. Leaf area and p e t i o l e l e n g t h Leaf area and p e t i o l e l e n g t h (Date 20-7-77) (Date 20-10-77) Treatment No. Name Regression Equation C o r r e l a t i o n C o e f f i c i e n t Regression Equation C o r r e l a t i o n C o e f f i c i e n t 1 Stap l e s 1975 Y= 6.38+0.98X r=0.43 Y=13.37+0.21X r=0.13 2 O g i l v i e 1975 Y= 8.73+0.53X r=0.34 Y= 8.46+0.82X ** r=0.65 3 M u l l i g a n 1976 Y= 8.03+0.22X r=0.12 Y=13.78-0.001X r=0.0007 4 Eastman 1975 Y= 6.64+0.96X r=0.69 Y= 4.88+1.28X ftft r=0.74 r. Eastman 1976 Y=11.24+0.02X r=0.02 Y=11.90-0.07X r=-0.03 Leaf area - X; P e t i o l e Length - Y: Leaf area - X; P e t i o l e Length - Y Sample s i z e - 24 observations per treatment, r.05(22) = 0.4143* r.01(22) = 0.5268** 124 Table 4 . 1 0 . 4 . 1 Top weight i n grams f o r f i v e s t r a i n s o f white c l o v e r grown i n a uniform nursery at U. .B.C. S t r a i n Source Mean SD CV % Range 1 Staples 1975 139.6 48.3 35 71.3-244 .8 2 O g i l v i e 1975 146.7 37.8 26 81.0-218. .7 3 M u l l i g a n 1976 90.6 17.7 20 60.2-133. .3 4 Eastman 1975 129.1 50.3 39 75.3-260. ,7 5 Eastman 1976 123.2 30.3 25 80.8-186. 0 Number of samples f o r each treatment - 24. Table 4 . 1 0 . 5 . 1 Height i n centimeters f o r f i v e s t r a i n s of white c l o v e r grown i n a uniform nursery at U.B.C. S t r a i n Source Mean SD 1 Staples 1975 17.4 2.8 2 O g i l v i e 1975 18.7 6.2 3 M u l l i g a n 1976 15.4 2.9 4 Eastman 1975 15.5 4.9 5 Eastman 1976 14.9 3.2 CV % 16 33 19 32 22 Range 7- 22 9-29 9-19 6-23 8- 20 Number of samples f o r each treatment - 24. Figure 4.10.4.1 The v a r i a t i o n i n top weight for plants grown from cuttings i n a uniform nur- sery; the f i v e strains at random i n each of four blocks; each s t r a i n represented by nine plants i n ultimate p l o t s ; u l - timate plots located at random within each block, showing: a) The arithmetic mean for each s t r a i n • b) The simple range by v e r t i c a l bar c) ± one standard deviation from the mean by horizontal bars U.B.C. Clones: Top weight I2S ir. £ CD 2 8 0 2 2 0 160 k 100 0»- I 3 S T R A I N 5 126 Table 4.10.4.2 Mean, weight and standard d e v i a t i o n o f top growth w i t h i n clones from f i v e s t r a i n s of white c l o v e r grown i n a uniform nursery at U.B.C; three p l a n t s i n each clone, eight clones i n each s t r a i n . S t r a i n Source Mean S.D. CV 1 Staples 1975 139.63 15.91 11 2 O g i l v i e 1975 146.67 10.13 7 3 M u l l i g a n 1976 90.62 14.40 16 4 Eastman 1975 129.11 14.29 11 5 Eastman 1976 123.19 14.65 12 Table 4.10.5.2 Mean, pla n t height and standard d e v i a t i o n w i t h i n clones from f i v e s t r a i n s of white c l o v e r grown i n a uniform nursery at U.B.C: three p l a n t s i n each clone, e i g h t clones i n each s t r a i n . S t r a i n Source Mean S.D. CV % 1 Staples 1975 17.42 1.75 10 2 O g i l v i e 1975 18.67 2.24 12 3 M u l l i g a n 1976 15.38 1.31 9 4 Eastman 1975 15.54 1.48 10 5 Eastman 1976 14.92 1.80 12 127 4.10.5 V a r i a t i o n i n plant height 4.10.5.1 Materials and methods Plant height was measured i n early September. The measurement was made i n centimeters by measuring the distance from the ground to the upper surface of the plant canopy. Single leaves above the canopy l e v e l were ignored. 4.10.5.2 Observations and r e s u l t s The F t e s t i n the analysis of v a r i a t i o n suggests d i f f e r e n c e s between s t r a i n s . The r e s u l t s are presented i n Table 4.10.5.1 and Figure 4.10.5.1. Table 4.10.5.2 gives average v a r i a t i o n that e x i s t s between plants within a clone for the 5 s t r a i n s . By comparing the c o e f f c i e n t of v a r i a t i o n i n Tables 4.9.6.1, 4.10.5.1 to 4.10.5.2 we observe that 54 percent of the v a r i a t i o n i n plant height i s a t t r i b u t e d to genetic f a c t o r s . Figure k.10.5.1 The v a r i a t i o n i n height of white clover plants grown from cuttings i n a uniform nursery; the f i v e strains at random i n each of four blocks; each s t r a i n repre- sented by nine plants i n ultimate p l o t s ; ultimate plots located at random within each block, showing: a) The arithmetic mean for each s t r a i n i b) The simple range by v e r t i c a l bar c) one standard deviation from the mean by horizontal bars U.B.C. Clones: Plant Height 0-~ 3 STRAIN 129 4.10.6 V a r i a t i o n i n Leaf Markings 4.10.6.1 M a t e r i a l s and Methods The l e a f markings observed were the i n v e r t e d "V" marks and the antho- cyanin f l e c k i n g marks. The grouping of the i n v e r t e d "V" l e a f mark and that f o r f l e c k i n g was by means of the simple observation of presence and absence. 4.10.6.2 Observations and Results Results o f counts of the i n v e r t e d "V" mark and anthocyanin f l e c k s are found i n Table 4.10.6.1, the presence of the l e a f mark g e n e r a l l y being the one i n greater abundance. Anthocyanin f l e c k s were more f r e q u e n t l y absent than present. I t was noted i n the f i e l d that a l l p l a n t s from each clone had s i m i l a r i n v e r t e d "V" l e a f marks and l e a f f l e c k s . Although p l a n t s were c o l - l e c t e d at random, i t i s i n t e r e s t i n g to note the d i f f e r e n c e i n r a t i o s of l e a f marks to no l e a f marks i n each s t r a i n . Table 4.10.6.2 gives the con- tingency t a b l e f o r the presence and absence of the two sets o f l e a f markings. 4.11 Coated Clover Seed T r i a l 4.11.1 M a t e r i a l s and Methods The t r i a l was undertaken on the Totem F i e l d at U.B.C. The seed used was of Creston o r i g i n and the coating process was done by Cel P r i l I n d u s t r i e s Inc., Manteca, C a l i f o r n i a . On June 23rd, the t r i a l was l a i d out and seeded on a three by three L a t i n square design, each p l o t being three meters by three meters. Treatments were a) coated seed, b) standard i n o c u l a t i o n , c) not i n o c u l a t e d . 4.11.2 Observations and Results On September 23rd one meter square quadrats were c l i p p e d from each p l o t , a i r - d r i e d i n the pot hole d r i e r and weighed to the nearest ounce. No s i g n i f i c a n t d i f f e r e n c e was observed between any of the treatments. 130 Table 4.10.6.1 Counts of l e a f marks f o r f i v e s t r a i n s of white c l o v e r grown as c l o n a l m a t e r i a l i n a uniform nursery at U.B.C. P l a n t s were v e g e t a t i v e l y propagated from m a t e r i a l of Creston o r i g i n . F i v e treatments, each treatment contained e i g h t groups with three g e n e t i c a l l y i d e n t i c a l p l a n t s i n each group. Plants w i t h i n v e r t e d P l a n t s w i t h i n v e r t e d Leaf mark Leaf mark S t r a i n Present Absent 1 9 (6) 15 (18) 2 12 (0) 12 (24) 3 24 (0) 0 (24) 4 15 (6) 9 (18) 5 18 (9) 12 (21) Plants outside of brackets - i n v e r t e d "V" mark. Plants i n s i d e of brackets - anthocyanin f l e c k s . Table 4.10.6.2 Contingency t a b l e f o r i n v e r t e d l e a f marks and anthocyanin f l e c k i n g on c l o n a l m a t e r i a l grown i n a uniform nursery at U.B.C. P l a n t s were v e g e t a t i v e l y propagated from m a t e r i a l of Creston o r i g i n . Five t r e a t - ments, each treatment contained e i g h t groups w i t h three g e n e t i c a l l y i d e n t i c a l p l a n t s i n each group. Anthocyanin Inverted "V" Leaf Marks l e a f f l e c k s Ab s ent Present T o t a l Absent 39 66 105 (40) (65) Present 9 12 21 (8) (13) T o t a l 48 78 126 2 X a c t u a l =0.26 X expected .05(1) : 131 4.11.3 D i s c u s s i o n The c o a t i n g of white c l o v e r seed under U.B.C. f i e l d c o n d i t i o n s d i d not give any appreciable increases i n establishment or y i e l d to that of uncoated seed, dusted or not dusted w i t h humus base r h i z o b i a l c u l t u r e . 4.12 Acetylene Reduction T r i a l s 4.12.1 M a t e r i a l s and Methods An ethylene analyzer (portable gas chromatograph) was constructed i n the Department of Plant Science at U.B.C. S p e c i f i c a t i o n s and design were followed c l o s e l y to those o u t l i n e d by M a l l a r d et a l . (1977). Gas chrom- atographic and t r o u b l e s h o o t i n g procedures were consulted from the t e x t by McNair and B o n e l l i (1969). The Taguchi gas sensor model No. T GS-812 was obtained from Southwest Techni c a l Products Corp., 219 West Rhapsody, San Antonio, Texas. The column packed with Poropak R and Poropak N (mesh s i z e 80-100) was ordered prepacked from Chromatographic S p e c i a l i s t s L t d . , P.O. Box 758, B r o c k v i l l e , Ontario. The length and diameter of the column was 44 cm x 3.18 mm (Mallard et a l . 1977). E l e c t r i c a l power f o r the analyzer was provided by a 12-volt car b a t t e r y . The c a r r i e r gas was n i t r o g e n at 20 ml/min. 4.12.2 Observations and R e s u l t s I t was found that good separation of ethylene from acetylene could be obtained from a c a r r i e r gas flow r a t e of 20 ml per minute. However t a i l i n g of the acetylene peak proved problematic. The c a r r i e r gas was then changed to compressed a i r and good separation of ethylene from acetylene was obtained w i t h no t a i l i n g o f the acetylene peak. S e n s i t i v i t y appeared good, with 1 part per m i l l i o n being detected when a sample of 1 ml was introduced. When 0.1 ml was i n j e c t e d , 10 p a r t s per m i l l i o n were detected under l a b o r a t o r y c o n d i t i o n s . 132 The column i s unheated and r e l i e s on the ambient a i r temperature. However moisture could become problematic i f samples are contaminated, rendering the column i n e f f e c t i v e . 14.12.3 D i s c u s s i o n I t i s considered that the u n i t i s s u f f i c i e n t l y accurate to detect nitrogenase a c t i v i t y as e a r l y as one hour a f t e r the beginning of in c u b a t i o n of samples i n s i t u i n s o i l . 133 5. GENERAL DISCUSSION AND CONCLUSIONS The i n f o r m a t i o n provided i n Table 1.1 shows that the present hectarage i n white c l o v e r t h a t i s grown i n the Creston V a l l e y of B r i t i s h Columbia i s a quarter of t h a t of a decade ago. Likewise, the y i e l d of seed per hectare has d e c l i n e d , w h i l e the p r i c e of common white c l o v e r seed has doubled i n the same time. The general trend f o r some markets of white c l o v e r seed, e s p e c i a l l y i n the European s e c t i o n , i s to c l o s e t h e i r doors on common seed and open them more a v i d l y to c e r t i f i e d seed. The r e t u r n s to growers f o r producing c e r t i f i e d seed are l u c r a t i v e , and i n general there i s a 15% increase i n seed p r i c e s f o r c e r t i f i e d over common seed. In the h i g h l y competitive markets f o r white c l o v e r seed on t h i s continent and elsewhere two t h i n g s appear to be i n demand: a) a statement of seed o r i g i n ( r e f l e c t i n g the c l i m a t e and management system under which i t i s produced), b) a name, along with the usual high standards of freedom from disease and weed seeds that accompany a c e r t i f i c a t e . The use and i n t e r e s t shown by some phases of a g r i c u l t u r e i n white c l o v e r has diminished over the years as the use of a r t i f i c i a l n i t r o g e n has increased. With the r i s i n g p r i c e s of f e r t i l i z e r n i t r o g e n the world over, i n t u r n a r e s u l t of the r i s i n g c ost of petroleum products, a general i n t e r e s t i n legumes and t h e i r n i t r o g e n f i x i n g a b i l i t y i s again apparent. I t i s u n l i k e l y that white c l o v e r w i l l be used i n very high y i e l d i n g grass pastures, but i t s a p p l i c a t i o n i n other s i t u a t i o n s i s i n c r e a s i n g (e.g., range r e h a b i l i t a t i o n , r e v e g e t a t i o n of mining s p o i l banks, roadsides and other a p p l i c a t i o n s ) . Changes i n marketing p o l i c y , together w i t h changes i n the a g r i c u l t u r a l and n o n - a g r i c u l t u r a l a p p l i c a - t i o n s are reasons f o r the Creston v a l l e y seed i n d u s t r y to reassess i t s r o l e . The seeking out of the causes f o r the d e c l i n e i n seed y i e l d and p e r s i s t - ence of the white c l o v e r crop i n the Creston v a l l e y i s one of the primary o b j e c t i v e s of t h i s study. Although the scope of the study was broad, areas such as those of disease could have been more f u l l y explored. 134 The i n v e s t i g a t i o n i n t o p o s s i b l e i n s e c t pests revealed that three species of weevil appear i n l a r g e enough populations to have a bearing on the apparent decrease i n seed y i e l d . The cumulative i n j u r y by these three weevil species must be of s i g n i f i c a n c e . Such e f f e c t s as lower f l o r e t f e r t i l i t y and seed damage by the ad u l t s and l a r v a e of the c l o v e r seed weevil are apparent (see Table 4.3.4.2). Poor development of seeds may w e l l r e s u l t from i n t e r r u p t e d t r a n s l o c a t i o n as a r e s u l t of l a r v a l feeding on the roo t s (see Table 4.1.4.1). The a c t i o n o f the c l o v e r root c u r c u l i o l a r v a e leads to a weakening of the stand, weed i n f e s t a t i o n , poor seed f i l l i n g , pathogen entry, p l a n t s t r e s s and and l o s s o f p l a n t p e r s i s t e n c e . The l a c k o f p e r s i s t e n c e i n the white c l o v e r seed crop, apparently r e l a t e d to weevil i n c i d e n c e , renders i t impossible f o r the farmer to keep the crop longer than one seed harvest. The long-term con- sequences of t h i s w i l l lead to a n a t u r a l s e l e c t i o n o f p l a n t s f o r a b i e n n i a l h a b i t . This may w e l l be of importance to the seed trade because white c l o v e r i s normally a l o n g - l i v e d p e r e n n i a l i n a g r i c u l t u r a l p r a c t i c e . The trade i s not l i k e l y to be much i n t e r e s t e d i n s t r e s s i n g l a s t i n g p e r s i s t e n c e . The sampling methods al s o revealed other organisms, such as s l u g s , nematodes and rodents. These organisms should not be overlooked f o r the damage they too can cause. Although c o n t r o l by chemical means i s p o s s i b l e , t h e i r presence i n the crop was observed to be spor a d i c , both i n time and l o c a t i o n . I f e e l that they are not the p r i n c i p a l causes of the general seed y i e l d d e c l i n e but are c o n t r i b u t o r y . S o i l f e r t i l i t y and r e a c t i o n t e s t s i n d i c a t e d that the n u t r i e n t s and hydrogen i o n concentrations were not l i m i t i n g p l a n t growth. However, the high s o i l r e a c t i o n and calcium content lead me to b e l i e v e that there i s a general need by Creston white c l o v e r f o r e x t r a phosphorus f e r t i l i z e r . The calcium ions combine with the a p p l i e d phosphate f e r t i l i z e r to form p r i n c i p a l l y d i c a l c i u m phosphate which i s a r e l a t i v e l y u n a v a i l a b l e form to p l a n t s . In 135 adjacent a l f a l f a crops, boron d e f i c i e n c y was noted on s e v e r a l occasions; i t was not noted i n white c l o v e r f i e l d s . The sampling of seed and phytomas revealed that there i s a l a r g e v a r i a - t i o n i n y i e l d both w i t h i n and between f i e l d s . Some general trends were observ One of these trends that the heavy top growth of white c l o v e r does not n e c e s s a r i l y mean heavier seed y i e l d . In other areas where white c l o v e r i s grown f o r seed, notably B r i t a i n , d e f o l i a t i o n of the crop i n e a r l y summer i s p r a c t i c e d . Leguminous crops, other than white c l o v e r , b e n e f i t from an e a r l y summer c u t t i n g , which s t i m u l a t e s r e p r o d u c t i v e growth as opposed to v e g e t a t i v e growth, and which helps c r e a t e a more open stand. I t was observed that f i f t y percent of the v e g e t a t i v e growth at Creston takes p l a c e p r i o r to the end of May. A s i m i l a r p r a c t i c e o f v e g e t a t i v e removal e a r l y i n the season i n the Creston v a l l e y may prove b e n e f i c i a l , but allowance i n time must be made f o r a carbohydrate build-up f o r seed production. Too l a t e a c u t t i n g w i l l lead to poor seed production. F l o r a l bud i n i t i a t i o n i s stimulated by t h i s p r a c t i c e of opening up the stands and i t was observed at Creston that the number of i n f l o r e s c e n c e s was s t r o n g l y a s s o c i a t e d w i t h seed y i e l d . Legumes, as p r e v i o u s l y mentioned, f i x t h e i r own n i t r o g e n , and consequently a high n i t r o g e n l e v e l i s maintained i n the s o i l . This widens the nigrogen-phosphorus r a t i o . This r a t i o widening creates a tendency f o r the white c l o v e r p l a n t to remain i n a v e g e t a t i v e s t a t e , as the phosphorus-nitrogen-carbon r a t i o s remain wide. However, by the a p p l i c a t i o n o f phosphorus to the seed crop, t h i s r a t i o i s narrowed and a balance main tai n e d f o r r e p r o d u c t i v e growth. By using phosphorus f o r t h i s purpose we are able to manipulate a crop i n t o r e p r o d u c t i v e growth without l o s i n g i t s genetic c a p a c i t y f o r v e g e t a t i v e growth. The p o t e n t i a l seed y i e l d s as measured by the quadrat method were almost always l a r g e r than those obtained by the grower. In some cases growers y i e l d s 136 were almost h a l f that of the p o t e n t i a l y i e l d . The e x p l a n a t i o n f o r t h i s being that considerable s h a t t e r i n g and seed head l o s s occurs at time of harvest. Plant s t r e s s can r e s u l t i n earlij m a t u r i t y , head and seed l o s s at harvest. I f e e l that p o l l i n a t i o n of the white c l o v e r seed crop at Creston i s not a problem. The recommendations i n e f f e c t i n other c o u n t r i e s lead to the con- c l u s i o n that each f i e l d i n the Creston v a l l e y had an adequate number of p o l - l i n a t o r h i v e s . Beehives are r o u t i n e l y placed i n each crop of white c l o v e r . In every case measurements of peduncle length were greater than p e t i o l e l e n g t h , ensuring adequate exposure of i n f l o r e s c e n c e s f o r bees. In the f i e l d i t was observed that i n f l o r e s c e n c e s were always w e l l above the f o l i a g e . I t may w e l l be that i t i s important to have i n f l o r e s c e n c e s w e l l exposed above the canopy f o r good p o l l i n a t i o n . However, i t was observed t h a t long stubble remaining a f t e r the previous g r a i n harvest and even weeds of low s t a t u r e such as dandelion and of course t a l l weeds such as p e r e n n i a l sow t h i s t l e appeared to stand w e l l above the crop. Such o b s t r u c t i o n s could lead to poor bee a c t i v i t y on the white c l o v e r . The c l i p p i n g of weeds i n f i e l d 6 could be r e s p o n s i b l e f o r the high number of seeds per head, while i n f i e l d 5, where there was a heavy i n f e s t a - t i o n of dandelions, we have a lower seed count per i n f l o r e s c e n c e . A c u t t i n g of top growth i n e a r l y summer would l i k e l y d i m i n i s h t a l l weeds. The malathion spray coming on the 22nd of June was observed to deter but not h a l t bee a c t i v i t y f o r about two days. This spray comes when the crop i s i n f u l l bloom and a small drop i n seed y i e l d may be apparent. T o t a l p l a n t n i t r o g e n (Table 4.4.1) demonstrated that the m a j o r i t y of n i t r o g e n f i x a t i o n occurred p r i o r to the end of May. In some cases a d e f i c i t i n p l a n t n i t r o g e n occurs and t h i s could be a r e s u l t of the feeding by the l a r v a of the c l o v e r root c u r c u l i o on the p l a n t nodules and r o o t s . The K j e l d a h l n i t r o g e n determination i s not' n e a r l y as s e n s i t i v e as the a c e t y l e n e - r e d u c t i o n technique i n measuring the a b i l i t y o f a plant-system to 137 " f i x " atmospheric n i t r o g e n . The K j e l d a h l a n a l y s i s i s al s o d e s t r u c t i v e and consequently does not allow f o r repeated observations. I t took me a long time to adapt the ace t y l e n e - r e d u c t i o n technique to my c o n d i t i o n s . With the help of Mr. Ilmars Derics we constructed a p o r t a b l e f i e l d u n i t ( s i m i l a r to M a l l a r d et a l . 1977) f o r measuring the production of ethylene. The use of the acetylene- r e d u c t i o n technique and f i e l d measurement of ethylene produced could be a very u s e f u l measure of the e f f e c t by the c l o v e r root c u r c u l i o on the white c l o v e r system. The observations c a r r i e d out at U.B.C. were made l a r g e l y on s i n g l e p l a n t s . The date of f l o w e r i n g and number of : inforescences produced are important to forage seed production. I t i s i n the i n t e r e s t s of the grower that a p l a n t produces, the maximum amount o f seed and t h i s i s one reason why seed production i s o f t e n to be c a r r i e d out i n an area other than i t s area of great e s t .use f o r forage. As documented, white c l o v e r i n i t i a t e s r e p r o d u c t i v e growth i n response to daylength and temperature. White c l o v e r i s a long day species and d i f f e r e n t s t r a i n s respond i n t h e i r f l o w e r i n g to d i f f e r e n t combinations of temperature and daylength. I t appears from one year's i n f o r m a t i o n t h a t the Creston s t r a i n s are w e l l adapted to the l a t i t u d e f o r seed production. Leaf area and p e t i o l e length i n white c l o v e r are important i n h e l p i n g to c a t e g o r i z e s t r a i n s as to t h e i r v a r i o u s forage uses. To elab o r a t e , Ladino c l o v e r , which has a l a r g e l e a f area and p e t i o l e l e n g t h , i s used f o r short-term hay and grazing pastures where the a b i l i t y to withstand heavy gr a z i n g i s not e s s e n t i a l . However, the w i l d white c l o v e r s w i t h t h e i r small l e a f area and p e t i o l e length are s u i t e d to areas o f low f e r t i l i t y and have the a b i l i t y to p e r s i s t almost i n d e f i n i t e l y under heavy g r a z i n g . In my t r i a l on twenty s t r a i n s I found that the Japanese s t r a i n "Tohoku" i s of the la r g e - l e a v e d intermediate white c l o v e r while the Dutch s t r a i n "Barbian" i s small-leaved. 138 Leaf markings of the i n v e r t e d "V" type and the anthocyanin f l e c k i n g found on white c l o v e r p l a n t s i n my t r i a l v a r i e d c o n s i d e r a b l y , but l i t t l e d i s t i n c t i o n could be made between s t r a i n s . However, the L o u i s i a n a s t r a i n s stood out by t h e i r c o n s i s t e n t presence of the intense "V" l e a f mark. These are s t r a i n s from warmer c l i m a t e s . The anthocyanin marks, which are expressed to a greater extent under c o o l e r temperatures, show again that the s t r a i n s from the warmer clim a t e s favour t h e i r absence. The contingency t a b l e (Table 4.9.5.6) shows the independent i n h e r i t a n c e , of the two l e a f marks, from each other. The measure of cyanogenesis, because of the negative r e a c t i o n s i n the s t r a i n s from the Creston v a l l e y , appears to be of l i t t l e use. However, i f the Danish s t r a i n "Pajberg m i l k a or K i v i " were being grown, then the t e s t could be of use due to i t s o c c a s i o n a l cyanogenic r e a c t i o n . Again, as has been documented i n the l i t e r a t u r e , s t r a i n s grown i n warmer c l i m a t e s ( v i z . i n our t r i a l s L o u i s i a n a s t r a i n s ) were cyanogenic. Plant weight d i d not separate out s t r a i n s i n the f i r s t c ut; however, i n the second harvest p l a n t weight was u s e f u l i n separating out s t r a i n s t h a t have a good f a l l recovery a f t e r d e f o l i a t i o n . This was w e l l d i s p l a y e d by the L o u i s i a n a s t r a i n s which had a heavier weight on the second c u t . I t i s f e l t t h at t h i s good regrowth and cyanogenic r e a c t i o n of s t r a i n s of southern o r i g i n can lead to a poor p e r s i s t e n c e i n the more northern l a t i t u d e s . The Creston s t r a i n s , with f a l l dormancy-aid smaller leaves, should d i s p l a y a g r e a t e r degree of hardiness. The purpose of p l a n t i n g the c l o n a l m a t e r i a l was to compare the non- i n h e r i t e d v a r i a b i l i t y w i t h that of the p l a n t s produced from seed. The measurements of l e a f area, p e t i o l e l e n g t h , p l a n t height and weight were compared by using the c o e f f i c i e n t of v a r i a t i o n . I t was observed that there e x i s t s s u b s t a n t i a l n o n - i n h e r i t a b l e v a r i a t i o n w i t h i n the c l o n a l and seed m a t e r i a l a t t r i b u t a b l e to sampling e r r o r , s o i l c o n d i t i o n s or root damage. 139 Recommendations f o r f u r t h e r work: a) There should be more i n t e n s i v e monitoring of the i n s e c t p o p u l a t i o n s , e s p e c i a l l y the three major species of w e e v i l , w i t h a view to determining the most e f f e c t i v e c o n t r o l s . This would a l s o i n c l u d e the problem of not a f f e c t i n g the p o l l i n a t o r s . b) B i o l o g i c a l n i t r o g e n f i x a t i o n s t u d i e s should be c a r r i e d out to determine the a b i l i t y o f the Creston white c l o v e r to f i x atmospheric n i t r o g e n under f i e l d c o n d i t i o n s . c) There should be the development, by i n d i v i d u a l p l a n t s e l e c t i o n , from the present Creston white c l o v e r stocks of named land s t r a i n s . D o m e s t i c a l l y , two needs are apparent and two separate s t r a i n s should be considered. F i r s t , an intermediate type, s u i t e d to a hay and grazing system, with moderate per- s i s t e n c e . Second, a small-leaved type that i s s u i t e d to heavy gr a z i n g and poor edaphic and c l i m a t i c c o n d i t i o n s ; t h i s small-leaved type i s g r e a t l y needed f o r the range and n o n - a g r i c u l t u r a l r e h a b i l i t a t i o n p r o j e c t s o f t h i s p r ovince. d) The Creston v a l l e y i s i d e a l l y s u i t e d to the production o f white c l o v e r f o r seed; however, the management of the white c l o v e r crop needs r e v i s i o n . F i r s t , the p r a c t i c e o f e a r l y d e f o l i a t i o n i n the growing season of the f i r s t c l o v e r seed harvest needs c o n s i d e r a t i o n . Second, the s o i l s of the Creston v a l l e y are calcareous and the carryover of a v a i l a b l e phosphatic f e r t i l i z e r may be i n s u f f i c i e n t f o r optimum rep r o d u c t i v e growth. This would warrant a s p r i n g a p p l i c a t i o n o f superphosphate or t r i p l e superphosphate to the c l o v e r seed crop. These two management techniques would g r e a t l y a s s i s t the growers i n producing l a r g e r marketable q u a n t i t i e s o f seed. 140 L i t e r a t u r e C i t e d A l d r i c h , D.T.A. 1969: Clover r o t ( S c l e r o t i n i a t r i f o l i o r u m ) i n white c l o v e r and i t s i n f l u e n c e i n v a r i e t a l performance at d i f f e r e n t centres. E d i t e d by Lowe, J . i n White c l o v e r research pp 143-146. Occas. Symp. No. 6. B r i t . G r a s s l . Soc. A l l e n , R.B., McDonald, I.R. and C u l l e n , N.A. 1976: Herbage production of pasture legumes at three s i t e s i n Otago. Proc. New Zeal. G r a s s l . Ass. 37:182-195. Angseesing, J.P.A. and Angseesing, W.J. 1973: F i e l d observations on the cyanogenesis polymorphism i n T r i f o l i u m repens. Hered. 31: 276-282. Anslow, R.C. 1962: The production of some herbage species i n temperate regions. Commonwealth Agr. Bur. Atwood, S.S. 1942: Genetics of s e l f - c o m p a t i b i l i t y i n T r i f o l i u m repens. J . Amer. Soc. Agron. 34:353-364. Atwood, S.S. and S u l l i v a n , J.T. 1943: Inheritance of a cyanogenetic glucoside and i t s h y d r o l y z i n g enzyme i n T r i f o l i u m repens. J . Hered. 34:311-320. Barcikowska, B. 1976: Studies on some u t i l i t y features of the crosses T r i f o l i u m repens L. form Ladino X T r i f o l i u m repens L. form Cultum and on r e l a t i o n s h i p s between clones and t h e i r generative progeny. Genetica P o l o n i c a 17:191-210. Beinhart, G. 1963: E f f e c t s of environment on meristematic development, l e a f area and growth of white c l o v e r . Crop S c i . 3:209-213. Bergersen, F.J. 1970: The q u a n t i t a t i v e r e l a t i o n s h i p between n i t r o g e n f i x a t i o n and the ac e t y l e n e - r e d u c t i o n assay. Aust. J . B i o l . S c i . 23:1015-1025. Bishop, J.A. and Korn, M.E. 1969: Natural s e l e c t i o n and cyanogenesis i n white c l o v e r T r i f o l i u m repens L. Hered. 24:423-430. Board of A g r i c u l t u r e and F i s h e r i e s . 1913: Clover s i c k n e s s . L e a f l e t No. 271 Borror and DeLong. 1963: An I n t r o d u c t i o n to the Study of I n s e c t s . H olt Rinehart, and Winston, N.Y., Chicago, San F r a n c i s c o , Toronto, London Brewbaker, J.L. 1955: V - l e a f markings of white c l o v e r . J . Hered. 46-115-123. B r i t i s h Columbia Department of A g r i c u l t u r e . 1974: C l i m a t i c normals 1941-1970; extremes of record. Climate of B r i t . Columbia. 141 B r i t i s h Columbia Department of A g r i c u l t u r e . 1976: Disease-insect-weed- rodent c o n t r o l recommendations. F i e l d crop 1976-1977. Brougham, R.W. 1958: Leaf development i n swards of white c l o v e r ( T r i f o l i u m repens L.). New Ze a l . J . Agr. Res. 1:707-718. B u r r i s , R.H. 1974: Methodology. E d i t e d by Q u i s p e l , A. i n "The b i o l o g y of n i t r o g e n f i x a t i o n " , pp. 9-33. North-Holland P u b l i s h i n g Co. Amsterdam, Oxford. B u r r i s , R.H. 1975: The acetylen e - r e d u c t i o n technique. E d i t e d by Stewart, W.D.P. i n Nitrogen f i x a t i o n of f r e e - l i v i n g micro- organisms, pp. 249-257. Cambridge Univ. Press. Burns, R.C. and Hardy, R.W.F. 1975: Nitrogen f i x a t i o n i n b a c t e r i a and higher p l a n t s . S p r i n g e r - V e r l a g . N.Y., Heidelberg, B e r l i n . Cahn, M.G. and Harper, J.L. 1976 a: The b i o l o g y of the l e a f mark polymorphism i n T r i f o l i u m repens L.: 1. D i s t r i b u t i o n o f phenotypes at a l o c a l s c a l e . Hered. 37:309-325. Cahn, M.G. and Harper, J.L. 1976 b: The b i o l o g y of the l e a f mark polymorphism i n T r i f o l i u m repens L.: 2. Evidence f o r the s e l e c t i o n of l e a f marks by f i s t u l a t e d sheep. Hered. 37:327-333. Canada Department of Mines and Techni c a l Surveys. 1957: A t l a s of Canada. Geographical Branch, Ottawa. Caradus, J.R. 1977: S t r u c t u r a l v a r i a t i o n of white c l o v e r root systems. New Z e a l . J . Agr. Res. 20:213-219. Caradus, J.R. and Evans, P.S. 1977: Seasonal root formation of white c l o v e r , ryegrass and cocksfoot i n New Zealand. New Ze a l . J . Agr. Res. 20:337-342. Carlson, G.E. 1966 a: Growth o f c l o v e r leaves - developmental morphology and parameters at ten stages. Crop S c i . 6:293-294. Carlson, G.E. 1966 b: Growth of c l o v e r leaves a f t e r complete or p a r t i a l l e a f removal. Crop S c i . 6:419-422. Carnahan, H.L., H i l l , H.D., Hanson, A.A. and Brown, K.G. 1955: I n h e r i t - ance and frequencies o f l e a f markings i n white c l o v e r . J . Hered. 46:109-114. Chapman, H.D. and P r a t t , P.F. 1961: Methods o f a n a l y s i s f o r s o i l s , p l a n t s and waters. Univ. C a l i f . Div. Agr. S c i . Charles, A.H.. 1968: Some s e l e c t i v e e f f e c t s operating on white and red - c l o v e r i n swards. J . B r i t . G r a s s l . Soc. 23:20--25. Chestnutt, D.M.B. and Lowe, J . 1969. White c l o v e r / g r a s s r e l a t i o n s h i p s ; review. E d i t e d by Lowe, J . i n White c l o v e r research pp. 191-213 Occas. Symp. No. 6. B r i t . G r a s s l . Soc. 142 Connor, A.J. 1949: The f r o s t - f r e e season i n B r i t i s h Columbia. Depart- ment of Transport Meteorol. Div., Ottawa. Cooper, J.P. 1969: P o t e n t i a l forage production. E d i t e d by L i P h i l l i p s and Hughes, R. i n Grass and forage breeding pp. 5-13. Occas. Sump. No. 5, B r i t . G r a s s l . Soc. C o r k i l l , L. 1942: Cyanogenesis i n white c l o v e r ( T r i f o l i u m repens L.) . V. The i n h e r i t a n c e of cyanogenesis. New Zeal. J . S c i . Technol. 2B:178-193. C o r r k i l l , L. 1971: Leaf markings i n white c l o v e r . J . Hered. 62:307-310. Crawford-Sidebotham, .T.J. 1972: The r o l e of slugs and s n a i l s i n the maintenance of the cyanogenesis polymorphisms of Lotus c o r n i c u l a t u s and T r i f o l i u m repens. Hered. 28:405-411. Crowder, L.V. 1960: Notes The response of white c l o v e r v a r i e t i e s grown at high e l e v a t i o n s i n Colombia. Agron. J . 52:608-609. Daday, H. 1954 a: Gene frequencies i n s t r a i n s of T r i f o l i u m repens L. Nature 174:521. ________ 1954 b: Gene frequencies i n w i l d populations of T r i f o l i u m repens L. I . D i s t r i b u t i o n by l a t i t u d e . Hered. 8:61-78. 1954 c: Gene frequencies i n w i l d populations of T r i f o l i u m repens L. I I . D i s t r i b u t i o n by a l t i t u d e . Hered. 8:377-384. 1955: Cyanogenesis i n s t r a i n s of white c l o v e r ( T r i f o l i u m repens L.) . J . B r i t . G r a s s l . Soc. 10:266-274. 1965: Gene frequencies i n w i l d populations of T r i f o l i u m repens L. IV. Mechanism of n a t u r a l s e l e c t i o n . Hered. 20: 355-365. Davidson, R.H. and P e a i r s , L.M. 1966: Insect pests of farm, garden and orchard. John Wiley and Sons. N.Y., London, Sydney. Davies, W.E. 1958: The y i e l d s of pure sown p l o t s of eight white c l o v e r s t r a i n s under c u t t i n g . J . B r i t . G r a s s l . Soc. 13:34-38. 1963: Leaf markings i n T r i f o l i u m ' r e p e n s . E d i t e d by D a r l i n g t o n , CD. and Bradshaw, A.D. i n Teaching Genetics. O l i v e r and Boyd, Edinburgh and London. 1969: White c l o v e r breeding; review. E d i t e d by Lowe, J . i n white c l o v e r research, pp. 99-122. Occas. Symp. No. 6 B r i t . G r a s s l . Soc. De Araujo, A.M. 1976: The r e l a t i o n s h i p between a l t i t u d e and cyano- genesis i n white c l o v e r ( T r i f o l i u m repens L.) . Hered. 37:291-293. 143 Denne, M.P. 1966: Leaf development i n T r i f o l i u m repens L. Bot. Gazz. 127:202-210. De t w i l e r , J.D. 1923: Three l i t t l e - k n o w n c l o v e r i n s e c t s . B u l l . 420. C o r n e l l Univ., N.Y. Department of Mines and Technica l Surveys. 1957: A t l a s of Canada. Geogr. Br., Ottawa. Dexter, S.T. and McKibben, E.G. 1945: Vacuum-type harvester f o r white c l o v e r seed. Mich. Agr. Exp. Sta. Quart. B u l l . 27:1-4. Dickason, E.A., Leach, CM. and Gross, A.E. 1958: Cont r o l o f the cl o v e r root c u r c u l i o s on a l s i k e c l o v e r . J . Econ. Entomol. 51:554-555. , and 1968: Clover root c u r c u l i o i n j u r y and v a s c u l a r decay of a l f a l f a r o o t s . J . Econ. Entomol. 61:1163-1168. D i l l o n Weston, W.A.R. 1950: Clover s i c k n e s s . Proceedings o f the A s s o c i a t i o n of Ap p l i e d B i o l o g i s t s . Ann. Appl. B i o l . 37:320-323. Dobson, J.W. and Beaty, E.R. 1977: Forage y i e l d s of f i v e p e r e n n i a l grasses w i t h and without white c l o v e r at four n i t r o g e n r a t e s . J . Range Manage. 30:461-465. Dominion Department of A g r i c u l t u r e . 1941: White c l o v e r i n Canada. Spec. Pam. No. 53 Forage Crops Div. E l l i o t , CR. and Howe, G.M. 1977: Forage i n t r o d u c t i o n s , P u b l i c a t i o n No. 77-16. Can. Agr. and A l b e r t a Agr. Ennik, G.C. 1969: White clo v e r / g r a s s r e l a t i o n s h i p s ; competition e f f e c t s i n l a b o r a t o r y and f i e l d ; review. E d i t e d by Lowe, J . i n White c l o v e r research, pp. 165-174. Occas. Symp. No. 6. B r i t . G r a s s l . Soc. E r i t h , A.G. 1924: White c l o v e r ( T r i f o l i u m repens L . ) . A monograph. Duckworth and Co., London. FAO of the United Nations. 1961: A g r i c u l t u r a l and h o r t i c u l t u r a l seeds; t h e i r p r o d u c t i o n , c o n t r o l and d i s t r i b u t i o n . FAO- A g r i c u l t u r a l s t u d i e s No. 55. Fishbeck, K., Evans, H.J. and Boersma, L.L. 1973: Measurement of nitrogenase a c t i v i t y of i n t a c t legume symbionts i i i s i t u using the acetylene r e d u c t i o n assay. Agron. J . 65:429-433. Fo r e s t e r , I.W., J e f f e r y , G.L. and Palmer-Jones, T. 1962: Factors causing losses of c l o v e r seed. New Zeal. J . Agr. Res. 5:326- 330. 144 Foy, N.R. and Hyde, E.O.C. 1937: I n v e s t i g a t i o n of the r e l i a b i l i t y of the p i c r i c - a c i d t e s t f o r d i s t i n g u i s h i n g s t r a i n s of white c l o v e r i n New Zealand. New Z e a l . J . Agr. 55:219-224. Frankton, C. 1955: Weeds of Canada. P u b l i c a t i o n 948. Can. Dep. Agr. Ga r r i s o n , C S . and Bula, R.J. 1961: Growing seeds of. forages outside t h e i r regions of use. Seeds. The yearbook o f A g r i c u l t u r e 1961. pp. 401-406. U.S. Dep. Agr. Gibson, P.B. 1957: E f f e c t of f l o w e r i n g on the p e r s i s t e n c e o f white c l o v e r . Agron. J . 49:213-215. Goodey, T. 1950: Stem eelworm and c l o v e r . Proceedings of the Assoc- i a t i o n of Ap p l i e d B i o l o g i s t s . Ann. Appl. B i o l . 27:324-327. Green, H.B. 1957: White c l o v e r p o l l i n a t i o n w i t h low honey bee popula- t i o n . J . Econ. Entomol. 50:318-320. Gyr i s c o , G.G. 1977: B i o l o g i c a l c o n t r o l of a l f a l f a w e e v i l . New York's Food and L i f e Sciences 10:14-16. Haggar, R.J., Holmes, W. and Innes P. 1963: Wild white c l o v e r seed production. 1. The e f f e c t s o f d e f o l i a t i o n and f e r t i l i z e r t r e a t - ment on f l o w e r i n g and seed y i e l d s from ryegrass/white c l o v e r swards. J . B r i t . G r a s s l . Soc. 18:97-103. . and . 1963 a: Wild white c l o v e r seed production. I I . A survey on w i l d white c l o v e r seed production i n Kent, 1961. J . B r i t . G r a s s l . Soc. 18:197-203. and . 1963 b: Kent w i l d white c l o v e r . Dep. Agr. Wye C o l l . , Ashford, Kent. H a l l i d a y , J . and Pate, J.S. 1976: The acetylene r e d u c t i o n assay as a means of studying n i t r o g e n f i x a t i o n i n white c l o v e r under sward and l a b o r a t o r y c o n d i t i o n s . J . B r i t . G r a s s l . Soc. 31:29-35. Hara, N. 1957. Study o f the var i e g a t e d leaves w i t h s p e c i a l reference to those caused by a i r spaces. Jap. J . Bot. 16:86-101. Harberd, D.J. 1963: Observations on n a t u r a l clones of T r i f o l i u m repens L. New P h y t o l o g i s t 62:198-204. Hardy, R.W.F., Holsten, R.D., Jackson, E.K. and Burns, R.C 1968: The acetylene-ethylene assay f o r N f i x a t i o n : Laboratory and f i e l d e v a l u a t i o n . P l a n t P h y s i o l . 43:1185-1207. and S i l v e r , W.S. (E d i t o r s ) 1977: A t r e a t i s e on d i n i t r o g e n f i x a t i o n . Sec. 3: Biology. John Wiley and Sons, N.Y. and Gibson, A.H. ( E d i t o r s ) 1977: A t r e a t i s e on d i n i t r o g e n f i x a t i o n . Sec. 4: Agronomy and Ecology. John Wiley and Sons, N.Y. 145 Hawkins, R.P. 1953: I n v e s t i g a t i o n s on l o c a l s t r a i n s of herbage p l a n t s . I I . Types of red c l o v e r and t h e i r i d e n t i f i c a t i o n . J . B r i t . G r a s s l . Soc. 8:213-238. . 1956: A p r e l i m i n a r y survey of red c l o v e r seed produc- t i o n . Proceedings of the A s s o c i a t i o n of A p p l i e d B i o l o g i s t s . Ann. Appl. B i o l . 44:657-664. . 1959: B o t a n i c a l characters f o r the c l a s s i f i c a t i o n and i d e n t i f i c a t i o n of v a r i e t i e s of white c l o v e r . J . Nat. I n s t . Agr. Bot. 8:675-682. . 1960. v I n v e s t i g a t i o n s on l o c a l s t r a i n s ( v a r i e t i e s ) of herbage p l a n t s : IV. White c l o v e r . J . B r i t . G r a s s l . Soc. 15: 28-33. Haystead, A. and Low, A.G. 1977: Nitrogen f i x a t i o n by white c l o v e r i n h i l l pasture. J . B r i t . G r a s s l . Soc. 32:57-63. H i l l , R.R., Newton, R.C., Z e i d e r s , K.E. and E l g i n , J.H. 1969: R e l a t i o n - ships of the c l o v e r root c u r c u l i o Fusarium w i l t and b a c t e r i a l w i l t i n a l f a l f a . Crop S c i . 9:327-329. H i l l , R.R., Murray, J . J . and Zeiders, K.E. 1971: R e l a t i o n s h i p s between c l o v e r root c u r c u l i o i n j u r y and s e v e r i t y of b a c t e r i a l w i l t i n a l f a l f a . Crop S c i . 11:306-307. H o l l o w e l l , E.A. 1948: Clovers that make a crop. Grass pp. 360-363. The Yearbook of A g r i c u l t u r e 1948. U.S. Dep. Agr. Howitt, A.J. 1961: Chemical c o n t r o l of slugs i n orchard grass- ladino white c l o v e r pastures i n the P a c i f i c north west. J . Econ. Entomol. 54:778-781. Hughes, H.D., Heath, M.E. and M e t c a l f e , D.S. 1966: Forages p. 374. Iowa State Univ. Press, Iowa. Imperial Bureaux of Pastures and Forage Crops 1939: B i b l i o g r a p h y on white c l o v e r ( T r i f o l i u m repens L.) . P u b l i c a t i o n No. 5. Aberystwyth, Great B r i t a i n . Jones, D.A. 1972: Cyanogenic g l y c o s i d e s and t h e i r f u n c t i o n . Edited by Harborne, J.B. i n Phytochem. E c o l . pp. 103-124. Academic Press,, London and N.Y. Jones, M.B., Delwiche, C.C. and W i l l i a m s , W.A. 1977: Uptake and l o s s of l^N a p p l i e d to annual grass and c l o v e r i n l y s i m e t e r s . Agron. J . 69:1019-1023. J e n k i n , T.J. 1943: Aberystwyth s t r a i n s of grasses and c l o v e r s . A g r i c u l t u r e L(8):343-349. 146 K e l l e y , C.C. and S p i l s b u r y . 1939: S o i l survey of the lower Fraser V a l l e y . P u b l i c a t i o n No. 650. Dominion Can. Dep. Agr. K i l p a t r i c k , R.A. and Dunn, G.M. 1961: Fungi and i n s e c t s a s s o c i a t e d w i t h d e t e r i o r a t i o n of white c l o v e r taproots. Crop S c i . 1:147-149. King, J.. 1961: Ecotypic d i f f e r e n t i a t i o n i n T r i f o l i u m repens. Plant and S o i l 18:221-224. K l e t e r , H.J. and Bakhuis, J.A. 1972: The e f f e c t of white c l o v e r on the production of young and o l d e r grassland compared to that of n i t r o g e n f e r t i l i z e r . J . B r i t . G r a s s l . Soc. 27:229-239. Koch, B. and Evans, H.J. 1966: Reduction of acetylene to ethylene by soybean root nodules. Plant P h y s i o l . 41:1748-1750. King, J . , Lamb, W.I.C., McGregor, M.T. 1978: E f f e c t o f p a r t i a l and complete d e f o l i a t i o n on regrowth of white c l o v e r p l a n t s . J . B r i t . G r a s s l . Soc. 33:49-55. K i r k , J.T.O. and T i l n e y - B a s s e t t , R.A.E. 1967: The p l a s t i d s pp. 92-102. W.H. Freeman and Co., London and San F r a n c i s c o . Lee, K.K. and Yoshida, T. 1977: An assay technique of measurement of nitrogenase a c t i v i t y i n root zone of r i c e f o r v a r i e t a l screening by the acetylene r e d u c t i o n method. Pla n t and S o i l 46:127-134. Lee, K., Alimaguo,' B. and Yoshida, T. 1977: F i e l d technique using the acetylene r e d u c t i o n method to assay nitrogenase a c t i v i t y and i t s a s s o c i a t i o n with the r i c e rhizosphere. Plant and S o i l 47:519-526. Liang, G.H. and Sorenson, E.L. 1977: Resistance of Medicago species to the a l f a l f a w e e v i l . Amer. Soc. Agron. L i e , T.A. 1971: Symbiotic n i t r o g e n f i x a t i o n under s t r e s s c o n d i t i o n s . Edited by L i e , T.A. and Mulder, E.G. i n B i o l o g i c a l n i t r o g e n f i x a t i o n i n n a t u r a l and a g r i c u l t u r a l h a b i t a t s . Plant and S o i l S p e c i a l Volume pp. 117-127. IBP. Lowe, J . ( E d i t o r ) 1969: White c l o v e r research. Occas. Symp. No. 6. B r i t . G r a s s l . Soc. McNair, H.M. and B o n e l l i , E.J. 1969: Basic gas chromatography. Va r i a n Aerograph, C a l i f . , S w itzerland and Can. M a l l a r d , T.M., M a l l a r d , C.S., H o l f e l d , H.S. and La Rue, T.A. 1977: Portable gas chromatograph f o r the acetylene r e d u c t i o n assay f o r nitrogenase. Anal. Chem. 49:1275-1277. Mann, H.H. 1950: Notes f o r paper on c l o v e r sickness ( n o n - p a r a s i t i c ) . Proceedings of the A s s o c i a t i o n of A p p l i e d B i o l o g i s t s . Ann. Appl. B i o l . 37:327-328. 147 Masterson, C.L. and Murphy, P.M. 1976. A p p l i c a t i o n of the acetylene r e d u c t i o n technique to the study of n i t r o g e n f i x a t i o n by white c l o v e r i n the f i e l d . Edited by Nutman, P.S. i n "Symbiotic n i t r o g e n f i x a t i o n i n p l a n t s " , pp. 299-316. IBP 7 Cambridge Univ. Press. M e l v i l l e , J . and Doak, B.W. 1940: Cyanogenesis i n white c l o v e r ( T r i f o l i u m repens L.) . I I . I s o l a t i o n of the g l u c o s i d a l con- s t i t u e n t s . New Z e a l . J . S c i . Techno 1'. 22:67B-71B. M i l l e r , D.F. 1958: Composition of c e r e a l grains and forages. NAC-NRC, Wash. D.C. Mirande, M." 1912: Sur l a presence de l ' a c i d e cyanhydrique dans l e t r e f l e rampant ( T r i f o l i u m repens L.) . C.R. Acad. S c i . P a r i s 155:651-653. Morgan-Jones, J . 1950: Clover seed w e e v i l s . Proceedings of the A s s o c i a t i o n of A p p l i e d B i o l o g i s t s . Annal. Appl. B i o l . 37:313-320. Moustafa, E., B a l l , R. and F i e l d , T.R.O. 1969: The use of acetylene r e d u c t i o n to study the e f f e c t of n i t r o g e n f e r t i l i z e r and d e f o l i a - t i o n on n i t r o g e n f i x a t i o n by f i e l d - g r o w n white c l o v e r . New Z e a l . J . Agr. Res. 12:691-696. Mulder, E.G., L i e , T.A. and Houwers, A. 1977: The importance of legumes under temperate c o n d i t i o n s . Edited by Hardy, R.W.F. and Gibson, A.H. i n A t r e a t i s e on d i n i t r o g e n f i x a t i o n . S e c t i o n 4. pp. 221-242. John Wiley and Sons, N.Y. Neal, J.W. and R a t c l i f f e , R.H. 1975: Clover root c u r c u l i o : C o n t r o l w i t h granular carbofuran as measured by a l f a l f a regrowth, y i e l d and root damage. J . Econ. Entomol. 68:829-831. Nowosad, F.S. and MacVicar, R.M. 1940: Adaptation of the p i c r i c - a c i d t e s t method f o r s e l e c t i n g HCN-free l i n e s i n sudan grass. S c i . Agr. 20:566-569. Nutman, P.S. 1976: Symbiotic n i t r o g e n f i x a t i o n i n p l a n t s . IBP 7. Cambridge Univ. Press. Cambridge. O'Rourke, C. 1969: White c l o v e r diseases i n the I r i s h Republic. Edited by Lowe, J . i n White c l o v e r research, pp. 139-142. Occas. Symp. No. 6. B r i t . G r a s s l . Soc. Page, B.G. and Thomson, W.T. 1976: The i n s e c t i c i d e , h e r b i c i d e , f u n g i c i d e quick guide. Thomson P u b l i c a t i o n s , C a l i f . Pankiw, P. and E l l i o t t , C.R. 1959: A l s i k e c l o v e r p o l l i n a t i o n by honey bees i n the Peace R i v e r r e g i o n . Can. J . Plant S c i . 39: 505-511. 148 Pesho, G.R. 1975: Clover root c u r c u l i o : Estimates o f l a r v a l i n j u r y to a l f a l f a tap r o o t s . J . Econ. Entomol. 68:61-65. Pusey, J.G. 1966: Cyanogenesis i n T r i f o l i u m repens. Edi t e d by D a r l i n g t o n , CD. and Bradshaw, A.D. i n Teaching g e n e t i c s , pp. 99-104. O l i v e r and Boyd, Edinburgh and London. Quispel, A. 1974: General i n t r o d u c t i o n . Edited by Q u i s p e l , A. i n The b i o l o g y of n i t r o g e n f i x a t i o n , pp. 1-8. North-Holland P u b l i s h i n g Co., Amsterdam and Oxford. Robinson, D.H. 1937: Leguminous forage p l a n t s . Edward Arnold and Co., London. Sch o l l h o r n , R. and B u r r i s , R.H. 1967: Acetylene as a competitive i n h i b i t o r of N 2 f i x a t i o n . Proc. Nat. Acad. S c i . (U.S.) 58:213-216. S i n c l a i r , A.G. 1973: Non-destructive acetylene r e d u c t i o n assay o f n i t r o g e n f i x a t i o n a p p l i e d to white c l o v e r p l a n t s growing i n s o i l . New Z e a l . J . Agr. Res. 16:263-270. , Hannagan, R.B. and R i s k , W.H. 1976: E v a l u a t i o n of the acetylene r e d u c t i o n assay of n i t r o g e n f i x a t i o n i n pastures using small s o i l - c o r e samples. New Z e a l . J . Agr. Res. 19:451-458. Smith, D., Lowe, H.J., Strommen, A.M. and Brooks, G.N. 1954: E s t a b l i s h - ment of legumes as i n f l u e n c e d by the r a t e of sowing the oat companion crop. Agron. J . 46:449-451. S t e i n , W. 1970: H i b e r n a t i o n of c u r c u l i o n i d s i n meadows and r e d - c l o v e r f i e l d s . Oecologia (Berl) 4:218-220. Stewart, W.D.P. ( E d i t o r ) . 1966: Nitrogen f i x a t i o n i n p l a n t s . The Athlone Press, London. , F i t z g e r a l d , C P . and B u r r i s , R.H. 1967: In s i t u s t u d i e s on N f i x a t i o n using the acetylene r e d u c t i o n technique. Proc. Nat. AcadT S c i . 58:2071-2078. , ( E d i t o r ) . 1975: Nitrogen f i x a t i o n by f r e e - l i v i n g micro- organisms: IBP 6. Cambridge Univ. Press, Cambridge. S t r i c k l a n d , A.H. 1956: Problems i n estimating i n s e c t pest damage to clover-seed crops. Proceedings of the A s s o c i a t i o n of Ap p l i e d B i o l o g i s t s . Annal. Appl. B i o l . 44:671-673. St u t z , R.C and B l i s s , L.C 1973: Acetylene r e d u c t i o n assay f o r n i t r o g e n f i x a t i o n under f i e l d c o n d i t i o n s i n remote areas. Short communication. Plant and S o i l 38:209-213. Swan, L.A. and Papp, C S . 1972: The common i n s e c t s of North America, p. 483. Harper and Row, N.Y. 149 Thomas, R.G. 1961: The i n f l u e n c e of environment on seed production c a p a c i t y i n white c l o v e r ( T r i f o l i u m repens L.) . A u s t r a l i a n J . Agr. Res. 12:227-238. . 1962: The i n i t i a t i o n and growth o f a x i l l a r y bud primordia i n r e l a t i o n to f l o w e r i n g i n T r i f o l i u m repens L. Ann. Bot. N.S. 26:329-344. Todd, J.R. 1969: Animal h e a l t h f a c t o r s . Edited by Lowe, J . i n White c l o v e r research, pp. 297-307. Occas. Symp. No. 6. B r i t . G r a s s l ; Soc. Turner, E.C., J r . 1957: C o n t r o l of the c l o v e r root c u r c u l i o i n a l f a l f a . J . Econ. Entomol. 50:645-648. U n d e r h i l l , G.W., Turner, E.C. and Henderson, R.G. 1955: C o n t r o l of the c l o v e r root c u r c u l i o on a l f a l f a w i t h notes on l i f e h i s t o r y and h a b i t s . J . Econ. Entomol. 48:184-187. United States Department of A g r i c u l t u r e . 1915: Hard c l o v e r seed and i t s treatment i n h u l l i n g . Farmers' b u l l e t i n No. 676. . 1924: Clover f a i l u r e . Farmers' b u l l e t i n No. 1365. . 1947: White c l o v e r . L e a f l e t No. 119. Vaughn, C E . and Jones, M.B. 1976: Nitrogen f i x a t i o n by i n t a c t annual rangeland species i n s o i l . Agron. J . 68:561-564. Vincent, J.M. 1974: Root-nodule symbiosis w i t h Rhizobium. Edited by Q u i s p e l , A. i n the b i o l o g y of n i t r o g e n f i x a t i o n , pp. 265-341. North Holland P u b l i s h i n g Co.,.Amsterdam and Oxford. . 1976: Rhizobium: General microbiology. Edited by Hardy, R.W.F. i n a T r e a t i s e on d i n i t r o g e n f i x a t i o n , pp. 277-366. John Wiley and Sons, N.Y. V i r t a n e n , A.I., Von Hausen, S. and Laine, T. 1937: I n v e s t i g a t i o n s on the root nodule b a c t e r i a of leguminous p l a n t s . 19. Influence of various f a c t o r s on the e x c r e t i o n of nitrogenous compounds from the nodules. J . Agr. S c i . 27:332. Walker, T.W., O r c h i s t o n , H.D. and Adams, A.F.R. 1954: The n i t r o g e n economy of grass legume a s s o c i a t i o n . J . B r i t . G r a s s l . Soc. 9: 249-274. Wallace, J.W. and M a n s e l l , R.L. 1975: Biochemical i n t e r a c t i o n between p l a n t s and i n s e c t s . Recent Advances i n Phytochemistry 10:229. 150 Ware, W.M. 1925: White c l o v e r . Misc. p u b l i c a t i o n No. 46. Min. Agr. F i s h , London. W i l l i a m s , R.F., Evans, L.T. and Ludwig, L. J . 1964: Es t i m a t i o n o f l e a f area f o r c l o v e r and lucerne. A u s t r a l i a n J . Agr. Res. 15:231-233. W i l l i a m s , T.E. 1959: Leys and subsequent arable p r o d u c t i v i t y . Winter meeting of the B r i t . G r a s s l . Soc. PP- 189-194. W i l l i a m s , W. 1945: V a r i e t i e s and s t r a i n s o f red and white c l o v e r - B r i t i s h and f o r e i g n . S e r i e s H, No. 16:19-26. Welsh Plant Breeding S t a t i o n , Wales. . 1969: White c l o v e r i n B r i t i s h A g r i c u l t u r e . E d i t e d by Lowe, J . i n White c l o v e r research, pp. 1-10. Occas. Symp. No. 6. B r i t . G r a s s l . Soc. W i l l i s , C.B. and Thompson, L.S. 1977: The e f f e c t s o f root l e s i o n nematodes on y i e l d of forage, legumes and grasses seeded alone and i n mixture. Can. J . Pla n t S c i . 57:315. Wilson, P.W. 1940: The biochemistry o f symbiotic n i t r o g e n f i x a t i o n . Univ. Wis. Press. Wittneben, U. and Sprout, P.N. 1971: S o i l survey o f the Creston area: Interim r e p o r t of the Creston V a l l e y s o i l survey. B r i t . Columbia Dep. Agr. Yeates, G.W. 1976: E f f e c t of f e r t i l i s e r treatment and st o c k i n g r a t e on pasture nematode populations i n a yellow-grey e a r t h . New Ze a l . J . Agr. Res. 19:405-408. , Healy, W.B. and Widdowson, J.P. 1976: E f f e c t of a s o i l fumigant on the establishment and growth of a grazed pasture on a yellow-brown loam. New Ze a l . J . Agr. Res. 19:397-403. , Ross, D.J., Bri d g e r , B.A. and V i s s e r , T.A. 1977: Influence of the nematodes Heterodera t r i f o l i i and Meloidogyne hapla on n i t r o g e n f i x a t i o n by white c l o v e r under glass house c o n d i t i o n s . New Zeal. J . Agr. Res. 20:401-413. Z a l e s k i , A. 1969: White c l o v e r seed production. Edited by Lowe, J . i n white c l o v e r research, pp. 147-154. Occas. Symp. No. 6. B r i t . G r a s s l . Soc. Figure 7-1 The Creston v a l l e y i n south-eastern B.C. i s s u i t a b l e f o r the production of high q u a l i t y white c l o v e r seed. Figure 7.2(a) White c l o v e r ranks as one of the world's more important forage p l a n t s . . . . i t s a p p l i c a t i o n i n other s i t u a t i o n s i s i n c r e a s i n g ( v i z . range r e h a b i l i t a t i o n ) . Figure 7.2(c) Forested range Figure 7.3(b) Creston s t r a i n s , w i t h l e s s f a l l recovery i n to growth, should d i s p l a y a greater p e r s i s t e n c e .  Figure 7.4(c) .even weeds of low s t a t u r e such as dandelions. Figure 7.4(d) ....and of course t a l l weeds such as p e r e n n i a l sow t h i s t l e . Figure 7-5(b) ....long stubble remaining a f t e r the previous year's g r a i n harvest... such o b s t r u c t i o n s could l e a d t o poor bee a c t i v i t y . Figure 7.7(a) ....white c l o v e r i n c e r t a i n areas of d i f f e r e n t s o i l t e x t u r e would flower prematurely. Figure 7.7(b) Flowering i n e a r l y June Figure 7-7(c) Matured by l a t e June Figure 7.8 The average number of i n f l o r e s c e n c e s per hectare was estimated t o be 11.5 m i l l i o n . F i g u re 7-9 ....beehives are r o u t i n e l y placed i n each crop of white c l o v e r . Figure 7.10(a) ....harvesting g e n e r a l l y commences when 90% of the heads are "brown". Figure 7.10(b) ....farmers are experiencing a seed l o s s , w h i l e har- v e s t i n g , of up to S0%. Figure 7 - l l ( l ) . . . . i t i s impossible f o r the farmer to keep the crop longer than one seed harvest. Figure 7.11(b) C h i s e l ploughed F i g u r e 7-13 w h i t e c l o v e r i s a s h o r t - l o n g day s p e c i e s a n d d i f f e r e n t s t r a i n s r e s p o n d i n t h e i r f l o w e r i n g t o d i f - f e r e n t c o m b i n a t i o n s o f t e m p e r a t u r e a n d d a y - l e n g t h . Figure 7 - l M b ) ...the p e t a l s are white but are o c c a s i o n a l l y pink. Figure 7.15(a) ...Louisiana s t r a i n s stood out by t h e i r c o n s i s t e n t presence of the i n v e r t e d "V" l e a f mark. Figure 7.15(b) P l a n t s w i t h no l e a f markings were i n the m i n o r i t y .

Cite

Citation Scheme:

    

Usage Statistics

Country Views Downloads
United States 39 3
United Kingdom 6 0
Japan 4 0
China 1 0
Russia 1 0
City Views Downloads
Washington 32 0
Unknown 10 19
Tokyo 4 0
Wilmington 1 0
Beijing 1 0
Mountain View 1 0
Sunnyvale 1 0
Ashburn 1 0

{[{ mDataHeader[type] }]} {[{ month[type] }]} {[{ tData[type] }]}

Share

Share to:

Comment

Related Items