@prefix vivo: . @prefix edm: . @prefix ns0: . @prefix dcterms: . @prefix skos: . vivo:departmentOrSchool "Forestry, Faculty of"@en ; edm:dataProvider "DSpace"@en ; ns0:degreeCampus "UBCV"@en ; dcterms:creator "Huxley, David Morton"@en ; dcterms:issued "2010-03-02T23:02:12Z"@en, "1978"@en ; vivo:relatedDegree "Master of Science - MSc"@en ; ns0:degreeGrantor "University of British Columbia"@en ; dcterms:description """In the Creston valley in southeastern B.C., intermediate white clover is grown for seed and is a useful crop in farm field rotations. For several years seed yields have been declining, and despite good prices and markets, hectarage to white clover is declining. In 1976, work was initiated to determine some of the factors responsible for the decline in seed yield and hectarage. At the same time, an exploratory study of the genetic variation in the seed stocks of the valley was instituted in the hope that a Creston strain might be characterized or selected. In 1977, in the Creston valley, a series of replicated plots in six fields, representative of the edaphic, climatic and management regimes, were established to measure seed and forage yields and losses from multiple sources. At the University of B.C., four hundred individual plants representative of twenty sources, including some Creston sources, and encompassing substantial genetic diversity, were established from seed in replicated uniform nurseries. In an adjacent nursery one hundred and eighty Creston clones were established. Observation and measurement of a number of characters were taken on all plants several times during the growing season. Average clean seed yields on the Creston experimental plots ranged from 468-972 kgs. per hectare (418-868 lbs per acre). Farm yields of clean seed, by contrast, ranged from 262-491 kgs per hectare (240 to 450 lbs per acre). It was estimated that of the loss in seed threshed (dockage) , but not cleaned, 3-10% was insect damaged; loss attributable to farm harvesting procedures was estimated to reach 50%. Losses in the developing crop are difficult to assess quantitatively but appeared to be very serious. To offset these losses, in recent years, producers have been reducing the length of white clover ley and are now in most cases obtaining one seed crop only in the year after establishment; this practice, if carried on without counter selection, might result in a biennial habit. Three species of weevil appeared to be the most serious pests, viz. the clover root curculio (Sitona hispidula Fab.), and the clover seed weevil (Miccotrogus picirostris (F)) and the lesser clover leaf weevil (Hypera nigrirostris Fab.). The population peaks of the adults apparently occur at different times in the season. Currently only one aerial application of malathion is applied in June to control the clover seed weevil. Almost all roots examined bore signs of larval feeding, doubtless due to the clover root curculio; root nodules, abundant in spring, diminished rapidly as the season progressed. Measurements of nitrogen fixation, using the acetylene reduction technique and the Kjeldahl N-determination, were incomplete. Flower frequency and development, flower colour, leaf area, petiole length, leaf markings, plant height and weight, and prussic acid levels were some of the characters measured and observed on the individual plants, established in the U.B.C. nurseries from Creston and other sources. Not unexpectedly, the Creston stocks possessed a measure of distinction from most other stocks of intermediate white clover; nonetheless, there appeared to be ample variability in the Creston stocks within which to select strains to meet at least two needs of the region - viz. a) plants useful in the revegetation of ranges and of unstable soils, and b) plants well adapted to the arable long ley pastures of the humid and sub-humid areas."""@en ; edm:aggregatedCHO "https://circle.library.ubc.ca/rest/handle/2429/21376?expand=metadata"@en ; skos:note "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 > | 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 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(cm2) 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. 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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 . "@en ; edm:hasType "Thesis/Dissertation"@en ; edm:isShownAt "10.14288/1.0075132"@en ; dcterms:language "eng"@en ; ns0:degreeDiscipline "Forestry"@en ; edm:provider "Vancouver : University of British Columbia Library"@en ; dcterms:publisher "University of British Columbia"@en ; dcterms:rights "For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use."@en ; ns0:scholarLevel "Graduate"@en ; dcterms:title "White clover seed production in British Columbia"@en ; dcterms:type "Text"@en ; ns0:identifierURI "http://hdl.handle.net/2429/21376"@en .