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The effect of certain fertilizer treatments on the composition of B.C. interior field tomatoes with special… McGibbon, Maxwell 1958

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THE EFFECT OF CERTAIN FERTILIZER TREATMENTS ON THE COMPOSITION OF B. C. INTERIOR FIELD TOMATOES WITH SPECIAL REFERENCE TO WATER-SOLUBLE PECTIN AS AN INDICATOR OF TOMATO FRUIT QUALITY. by MAXWELL McGIBBON A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IU AGRICULTURE i n H o r t i c u l t u r e We a c c e p t t h i s t h e s i s as conforming t o the s t a n d a r d r e q u i r e d from c a n d i d a t e s f o r the degree of MASTER OF SCIENCE I N AGRICULTURE Members o f the Department THE UNIVERSITY OF BRITISH COLUMBIA A p r i l 195S ABSTRACT Investigation into possible causes for reported, s o f t -ness of B.C. I n t e r i o r tomatoes revealed that processed tom-atoes from the Kelowna d i s t r i c t were firmer than processed tomatoes from the Vernon or Kamloops d i s t r i c t s . S o i l and plant material samples from the Kelowna d i s -t r i c t were r e l a t i v e l y high i n calcium and magnesium and low i n potassium compared to samples from Vernon which were r e l -a t i v e l y low i n calcium and magnesium and high i n potassium. Samples from the Kamloops d i s t r i c t were r e l a t i v e l y high i n calcium, magnesium and potassium. F r u i t samples from the Kelowna d i s t r i c t contained a s i g n i f i c a n t l y greater amount of water-soluble pectin than f r u i t from either Vernon or Kamloops. S o i l treatments with several nutrient elements did not produce a s i g n i f i c a n t e f f e c t on water-soluble pectin i n tomato f r u i t at Kelowna, Vernon or Kamloops, but treatments containing calcium appeared to pro-duce the most consistent e f f e c t . ACKNOWLEDGMENTS The author wishes to thank Dr. G.H. Harris, under whose d i r e c t i o n t h i s thesis was written, for his con-tinuing i n t e r e s t and many helpful suggestions. The author also wishes to thank Dr. C C . Strachan for his advice regarding pectin analyses; Dr. T.H. Anstey for assistance with s t a t i s t i c a l analysis of data; and Dr. J.C. V/ilcox and Dr. J".L. Mason for assistance with and use of laboratory f a c i l i t i e s f or chemical analysis of s o i l and plant material. TABLE OE CONTENTS P a g e INTRODUCTION 1 REVIEW OF LITERATURE 10 MATERIALS and METHODS 1953 Preliminary Survey 18 1954 F e r t i l i z e r Experiments 19 1955 Phosphorus Experiment 24 RESULTS 1953 Preliminary Survey 26 1954 F e r t i l i z e r Experiments 29 1955 Phosphorus Experiment 37 DISCUSSION 1953 Preliminary Survey 40 1954 F e r t i l i z e r Experiments • 41 1955 Phosphorus Experiment . 43 CONCLUSIONS 44 SUMMARY 46 .REFERENCES 47 THE EFFECT OF CERTAIN FERTILIZER TREATMENTS ON THE COMPOSITION OF B.C. INTERIOR FIELD TOMATOES WITH SPECIAL REFERENCE TO WATER-SOLUBLE PECTIN AS AN INDICATOR OF TOMATO FRUIT QUALITY. -INTRODUCTION About 2000 acres of fieldgrown tomatoes are planted In the B.C. I n t e r i o r each year which makes them one of the most important vegetable crops of the area. This acreage i s di s t r i b u t e d between several d i s t r i c t s including Keremeos i n the Similkameen va l l e y , O'soyoos i n the south Okanagan, Kelowna i n the central Okanagan, Vernon i n the north Okanagan and Kami oops and Ashcroft i n the Thompson r i v e r v a l l e y . The tomato crop i s sold both to processing companies and to the fresh market. The processing companies' main tomato product i s canned whole tomatoes but they also manufacture some tomato juice and tomato puree. Tomatoes for the fresh market are packed as mature greens, semi-ripes or turnings by indepen-dent packing houses and sold through the I n t e r i o r Vegetable Marketing Agency to markets i n Vancouver to the west or as far east as Winnipeg. -2-Both the tomato processors and the f r e s h f r u i t market demand certain q u a l i t y c h a r a c t e r i s t i c s i n the tomatoes that they buy and B.C. I n t e r i o r tomato growers must produce tomatoes with those qua l i t y c h a r a c t e r i s t i c s i f they are to hold and expand those markets. The f a c t that the tomato-growing industry has existed now f o r about f i f t y years indicates that B.C. I n t e r i o r tomatoes have s a t i s f i e d most of the quality requirements of the two markets but, i n the l a s t few years, there have been an increasing number of complaints from both markets concerning the q u a l i t y of tomatoes grown i n the B.C. I n t e r i o r . Such complaints must be taken seriously because they indicate a condition that could jeopardize the success and future development of the B.C. Int-e r i o r as a tomato-growing area. The q u a l i t y requirements of the two tomato markets are s i m i l a r . Both require tomatoes that are medium sized, globe-shaped, free from cracks or blemishes and m i l d l y acid i n flavour. In addition, the processing market prefers tomatoes that are bright deep red i n color and have the type of skin that peels e a s i l y . Tomatoes processed as canned whole tomatoes must also r e t a i n most of t h e i r wholeness i n the can a f t e r being subjected to the handling procedures and high temperatures encountered during the canning process. Tomatoes for the fr e s h market must be able to develop an a t t r a c t i v e red color when ripened off the vine a f t e r being picked and shipped i n the green or semi-ripe state. - 3 -The main complaint from tomato processors concerning the quali t y of B.C. tomatoes i s that the tomatoes lack firmness. Occasional complaints are voiced concerning lack of s u f f i c i e n t color development or too high acid content but these complaints usually occur only during abnormally cool seasons or at the cool end of an otherwise normal season. They are generally a t t r i b -uted to lack of s u f f i c i e n t heat f o r normal tomato development and are considered to be one of the normal hazards of producing a semi-tropical crop i n a temperate climate. The condition of lack of firmness i s considered to be more serious. I t appears that i n ce r t a i n seasons or parts of seasons tomatoes processed as whole canned tomatoes tend to break down i n the cans a f t e r processing. The r e s u l t i s a s o f t , mushy product that i s down-graded because i t lacks firmness. Fresh f r u i t shippers, i n recent years, have received complaints from the f r e s h f r u i t markets that B.C. In t e r i o r toma-toes have arrived at market i n a s o f t , watery condition rend-ering them u n f i t for sale. On such occasions, rebates must be made to the buyers of such f r u i t and the B.C. industry loses a sale as well as being charged with the costs of packing and shipping. A more serious e f f e c t i s the loss of reputation f o r quali t y that B.C. tomatoes have had i n the fre s h f r u i t markets. Enquiry reveals that B.C. I n t e r i o r tomatoes usually appear normal when f r e s h l y picked and only exhibit softness a f t e r pro-cessing or shipping. This makes d i f f i c u l t the task of tracing -4-affected- f r u i t back to p a r t i c u l a r farms or d i s t r i c t s because the normal procedure of pooling and mixing l o t s of f r u i t at the packing shed or processing plant tends to cover up the i d e n t i t y of any p a r t i c u l a r l o t . Another factor that hinders tracing the condition of softness of B.C. tomatoes to any part-i c u l a r cause i s that the occurrence of softness s u f f i c i e n t to cause complaint i s not consistent. During some seasons a part-i c u l a r d i s t r i c t may be plagued with complaints f o r part of the season and then receive no complaints for the rest of the season. During other seasons some d i s t r i c t s may have more com-pl a i n t s than other d i s t r i c t s . There i s no known case where a l l the tomato f r u i t from the entire area exhibited softness at one time or that a l l the f r u i t from one d i s t r i c t exhibited softness at one time. Apparently, most d i s t r i c t s receive complaints at some time or other, and some d i s t r i c t s appear to receive more complaints than others. About the only generalization that can be made i s that complaints about tomato q u a l i t y are more common i n the Kamloops and Vernon d i s t r i c t s than they are i n the Kelowna or other d i s t r i c t s . The Osoyoos d i s t r i c t which spec-i a l i z e s almost e n t i r e l y i n producing e a r l y tomatoes for the fresh market receives occasional complaints about tomato qualit y , but most of the time f r u i t from that d i s t r i c t i s considered to be quite s a t i s f a c t o r y . The Keremeos d i s t r i c t has started pro-ducing tomatoes only recently. So f a r , few complaints have been received concerning the quality of tomatoes from there. -5-At present no d e f i n i t e cause i s known for the condition of softness that occurs i n B.C. I n t e r i o r tomatoes but there are several popular opinions advanced by people connected with the industry. Among these opinions, the increasing incidence of tomato softness i s blamed variously on the use of chemical f e r t -i l i z e r s , use of too much nitrogen, i n s u f f i c i e n t use of potash, depleted s o i l organic matter, the increasing use of sprinkler i r r i g a t i o n and the change from older to newer v a r i e t i e s of tomatoes. I f there i s truth i n the statements heard that the pro-blem of tomato softness i s a f a i r l y recent one that did not exi s t i n e a r l i e r years of the industry, then such factors as newer var-i e t i e s , depletion of s o i l organic matter, the use of chemical f e r t i l i z e r s instead of animal manures, changes i n c u l t u r a l prac-t i c e s such as changing from furrow i r r i g a t i o n to spr i n k l e r i r r i g -a tion, depletion of s o i l f e r t i l i t y by continued cropping and the recent introduction of tomato diseases a l l could be possible causes of deterioration of tomato q u a l i t y i n the B.C. I n t e r i o r . The only way to prove or disprove the e f f e c t of the foregoing opinions would be by c r i t i c a l examination of each one. A more p r a c t i c a l way to attempt to solve the problem would be to deduce from available f a c t s the most l i k e l y possible causes and then subject them to experiment. Some of the popular opinions regarding the cause of s o f t -ness of B.C. I n t e r i o r tomatoes can be eliminated or at l e a s t low--6-ered i n p r i o r i t y for c r i t i c a l examination. I t i s not l i k e l y that sprinkler i r r i g a t i o n would be a serious factor as a cause of tomato softness because the use of s p r i n k l e r i r r i g -ation i s widespread and i s known to be used i n d i s t r i c t s and on farms that show no apparent decline i n tomato quality. On the other hand, some d i s t r i c t s that report a high incidence of tomato softness s t i l l use more furrow i r r i g a t i o n than sprinkler i r r i g a t i o n . Tomato diseases would not appear to be a cause of tomato softness. The common tomato diseases present i n the area are also present i n most other tomato-growing areas and have not been reported to a f f e c t tomato firmness. The use of chemical f e r t i l i z e r s instead of animal manures i s an accepted a g r i c u l t u r a l practice i n a l l modern a g r i c u l t u r a l areas. Des-pite a preference f o r organic f e r t i l i z e r s by some people, chemical f e r t i l i z e r s are no longer considered to have any harmful e f f e c t on crops. A similar s i t u a t i o n exists i n regards to s o i l organic matter. Most a g r i c u l t u r a l opinion regards s o i l organic matter as a desireable f r a c t i o n of any a g r i c u l t u r a l s o i l , but not absol-utely e s s e n t i a l f o r healthy plant growth. Experiments i n which healthy plants are grown i n sand or solution cultures have d i s -proved the e s s e n t i a l i t y of organic matter i n s o i l s . The poss-i b l e e f f e c t of changes i n the v a r i e t i e s of tomatoes grown i n the area i s not known. O r i g i n a l l y , the variety E a r l i a n a was grown for the fresh market and John Baer was grown fo r the pro-cessing market. These v a r i e t i e s have been superseded i n recent years by such v a r i e t i e s as Clark's E a r l y , Stokesdale, Gem and -7-Valiant. I t does not seem l i k e l y that the newer v a r i e t i e s would be more susceptible to softness than the older v a r i e t i e s because they are grown i n a l l d i s t r i c t s and are also grown successfully i n other tomato-producing areas. However, the fact that t h e i r introduction coincides somewhat with the dev-elopment of complaints regarding tomato q u a l i t y prevents the e f f e c t of v a r i e t y from being excluded as a contributing factor to tomato softness. The opinions that softness of B.C. I n t e r i o r tomatoes i s connected with declining s o i l f e r t i l i t y or the kinds of f e r t i l -i z e r used for tomato production merit serious consideration. I t i s possible that continuing vegetable production has pro-duced certain s o i l nutrient d e f i c i e n c i e s that are not being corrected by present f e r t i l i z e r applications and that such d e f i c i e n c i e s are responsible for softness of tomato f r u i t . The f a c t that occurrences of softness are sporadic but appear to be increasing i n frequency and are i n c l i n e d to show up i n some d i s t r i c t s more than others suggests that there may be a nutrient deficiency condition i n the i n c i p i e n t stage. Such a condition could be more acute i n some d i s t r i c t s than others and possibly could be accentuated or repressed by cli m a t i c con-di t i o n s i n certain seasons or parts of seasons. A condition such as described would account for the sporadic occurrence of tomato softness, the fac t that the f r u i t would not show signs of deficiency except under stress such as that encountered i n shipping or processing, and the tendency for the trouble to be more severe i n some d i s t r i c t s than i n others. -8-N u t r i e n t e l e m e n t s a t p r e s e n t recommended f o r use on f i e l d tomatoes i n the B.C. I n t e r i o r i n c l u d e n i t r o g e n , p hosphorus, p o t a s s i u m and boron ( 4 ) . The most common f e r t i l i z e r used f o r tomatoes i s an 8-10-5 mix a p p l i e d a t about 500 pounds per a c r e . N i t r o g e n f e r t i l i z e r , e i t h e r i n organic: o r i n o r -g a n i c form, i s c o n s i d e r e d n e c e s s a r y f o r any p l a n t growth i n the a r e a because the s o i l , under s e m i - a r i d c o n d i t i o n s , does n o t accumulate n i t r o g e n . The phosphorus s t a t u s of the s o i l s i s n o t w e l l known but i s c o n s i d e r e d t o be l o w , a l t h o u g h phos-phorus i s n o t recommended f o r t r e e f r u i t s i n t h e a r e a . B.C. I n t e r i o r s o i l s a r e c o n s i d e r e d t o be w e l l s u p p l i e d w i t h p o t -a s s i u m . I t has not been recommended f o r t r e e f r u i t s f o r s e v -e r a l y e a r s , but i t i s s t i l l used on tomatoes l a r g e l y because i t i s a d v e r t i s e d as h a v i n g improved q u a l i t y o f tomatoes i n o t h e r p a r t s o f the w o r l d . The a r e a i s c o n s i d e r e d t o be gen-e r a l l y d e f i c i e n t i n boron and boron a p p l i c a t i o n s a r e recom-mended f o r a l l c r o p s . No m i c r o n u t r i e n t s o t h e r than boron a r e recommended f o r use on v e g e t a b l e c r o p s . A p p a r e n t l y , no d e f -i c i e n c i e s o f o t h e r m i c r o n u t r i e n t s have been r e c o g n i z e d i n v e g e t a b l e c r o p s a l t h o u g h d e f i c i e n c i e s o f magnesium, manganese and z i n c have been r e c o g n i z e d i n t r e e f r u i t c r o p s and s p e c i a l recommendations a re i s s u e d f o r t h e i r use on t r e e f r u i t s ( 3 ) . The s o i l s o f the a r e a a re c o n s i d e r e d t o be w e l l s u p p l i e d w i t h c a l c i u m . Some c h l o r o t i c c o n d i t i o n s t h a t appear on t r e e f r u i t s i n the a r e a a r e c o n s i d e r e d t o be caused by a l i m e i n d u c e d i r o n d e f i c i e n c y . -9-In view of the f a c t that d e f i c i e n c i e s of several nut-r i e n t elements are known to e x i s t i n the B.C. I n t e r i o r and because the nutrient status of tomato-growing s o i l s and tomato plants i n the area i s not well known, an investigation to det-ermine the nutrient status of tomato s o i l s and plants of the area would be desireable to see whether or not there could be a connection between nutrient status and the softness of f r u i t reported to exist i n B.C. I n t e r i o r tomatoes. I t would also be of i n t e r e s t to apply and test the e f f e c t of several plant nut-r i e n t s on the composition of the plants and the firmness of the f r u i t . Because differences i n the inherent firmness of B.C. In t e r i o r tomatoes often are apparent only after processing or shipping but d i f f i c u l t to detect i n f r e s h l y picked f r u i t , some objective test would be useful that would r e f l e c t changes i n the composition of fresh f r u i t that r e l a t e to firmness. Such a test would f a c i l i t a t e assessment of the e f f e c t of treatments intended to improve the. firmness of the f r u i t . In t h i s study, several factors connected with tomato quality were reviewed, an investigative survey of d i s t r i c t s producing extremes of tomato qua l i t y was made, a series of f e r t i l i z e r experiments were conducted and an objective test reported to r e f l e c t changes i n tomato quality was t r i e d out i n the hope that some of the information obtained, would be useful to the tomato industry of the B.C. I n t e r i o r . - 1 0 -REvTEW OF LITERATURE " Q u a l i t y " i s a term used to d e s c r i b e the o v e r a l l d e s i r e a b i l l t y of an a r t i c l e . I t i s the product of the e f f e c t s of s e v e r a l component f a c t o r s blended together to create a f i n a l i m p r e s s i o n . The e f f e c t of each of the f a c t o r s i s important but, i n d i f f e r i n g s i t u a t i o n s , the e f f e c t of some of the f a c t o r s may be more important than o t h e r s depending on the intended use f o r the a r t i c l e . Tomato q u a l i t y i s composed of the e f f e c t s of s e v e r a l f a c t o r s . Some of the most important of these f a c t o r s a r e : c o l o r , s i z e , shape, f l a v o r , freedom from blemishes, n u t r i e n t content and s o l i d i t y . The most g e n e r a l l y d e s i r e a b l e c o l o r f o r mature tomatoes i s a b r i g h t , deep r e d . I t has become the c o l o r t y p i c a l l y a ssoc-i a t e d w i t h tomatoes of h i g h q u a l i t y and o f t e n e x e r t s a d e c i s i v e i n f l u e n c e on the judgement of tomato q u a l i t y by the consumer. The t y p i c a l r e d c o l o r of tomato f r u i t i s produced by the pigment lycopene, ( 6 , 9 ) which i s an isomer of the yellow pigment caro-tene ( 6 ) . The f i n a l c o l o r of tomatoes i s co n s i d e r e d to be con-t r o l l e d by the carotene-lycopene r a t i o developed i n the f r u i t ( 8 , 9 ) . Each v a r i e t y of tomatoes develops a t y p i c a l c o l o r at m a t u r i t y so the carotene-lycopene r a t i o i s a f f e c t e d by the gen-e t i c makeup of each v a r i e t y ( 8 ) . Some v a r i e t i e s are y e l l o w --11-colored at maturity while other v a r i e t i e s are red-colored dep-ending on the r a t i o of carotene to lycopene developed by the variety. Mature tomato f r u i t s do not always develop the t y p i c a l color expected of the va r i e t y to which they belong. I t has been found that the carotene-lycopene r a t i o can be affected by temperature and the normal development of lycopene suppressed (8, 17, 22). Apparently, the development of carotene i s not affected by temperature (22) so i t i s common f o r presence of carotene to overbalance the e f f e c t of lycopene producing a yellow color i n normally red-colored tomatoes but i t i s not poss-i b l e f o r the development of lycopene to overbalance the e f f e c t of carotene and so produce redness i n normally yellow-colored tom-atoes. Lycopene does not develop normally at either low or high temperatures. I t has been found that tomatoes matured at day temperatures of 60° j?. and night temperatures of 45° F. did not develop t h e i r normal red color, or developed red color only a f t e r they were past optimum maturity (8, 22). On the other hand, v a r i e t i e s normally producing red-colored f r u i t , when mat-ured at day temperatures of 100° F., produced yellow to orange-colored f r u i t (17, 22). The normal red color expected of red-colored v a r i e t i e s has been found to develop best at or around day temperatures of 80° F. and night temperatures of 65° F. (22). In experiments to determine the optimum temperature f o r a r t i f i c i a l l y ripening tomatoes picked at the mature green stage, i t was found -12-that red color developed best at temperatures between 70° F. and 75° F. (25). Each variety of tomato generally produces f r u i t of ch a r a c t e r i s t i c size and shape, but the size of f r u i t may be affected by c u l t u r a l practices (20). I t i s common knowledge that f r u i t grown on plants well supplied with nutrients w i l l be larger than f r u i t grown on plants deprived of any of the essen-t i a l plant nutrients. The e f f e c t of adequacy or shortage of nitrogen probably has been noted more on the size of tomato f r u i t than any other plant nutrient element (20, 24). The fl a v o r of tomato f r u i t i s associated with the acids and sugars developed i n the f r u i t and the f i n a l f l a v o r i s con-sidered to be controlled by the r a t i o of t o t a l sugars to t o t a l acids (23). The development of sugars i s the r e s u l t of photo-synthetic a c t i v i t y and depends on the amount of sunlight absorbed by the plant (6, 14, 23). Some e f f e c t of c u l t u r a l practices on the sugar content of tomato f r u i t has been reported (13, 21). High application rates of nitrogen have resulted i n a decreased sugar content of tomato f r u i t (13) while high application rates\ of phosphorus and potassium are reported to have increased the sugar content (13). The t o t a l acid content of tomato f r u i t i s composed of several organic acids (6, 19-) but i t i s the ascorbic acid f r a c t i o n that has received the most inv e s t i g a t i o n since ascorbic acid, also known as vitamin C, i s the main n u t r i t i o n a l factor -13 a s s o c i a t e d w i t h tomatoes . A s c o r b i c a c i d c o n t e n t i s known to v a r y w i d e l y between v a r i e t i e s and between s p e c i e s of tomatoes . T h i s knowledge i s used to s e l e c t p a r e n t m a t e r i a l i n tomato b r e e d i n g programs d e s i g n e d to produce new tomato v a r i e t i e s o f h i g h a s c o r b i c a c i d c o n t e n t ( 2 6 ) . I t i s a l s o known t h a t the a s c o r b i c a c i d conten t o f the f r u i t o f any one v a r i e t y w i l l v a r y c o n s i d e r a b l y depending on c l i m a t i c c o n d i t i o n s . I t was found t h a t the a s c o r b i c a c i d c o n t e n t v a r i e d d i r e c t l y w i t h the amount and i n t e n s i t y o f l i g h t a v a i l a b l e t o the p l a n t (14 , 1 8 ) . I t was f e l t f o r some time t h a t the amount o f l i g h t absorbed by the p l a n t f o l i a g e c o n t r o l l e d the p r o d u c t i o n o f a s c o r b i c a c i d ( 1 4 ) , but l a t e l y i t has been demonst ra ted t h a t i t i s the amount o f l i g h t absorbed by the f r u i t i t s e l f t h a t a f f e c t s the amount o f a s c o r b i c a c i d formed i n the f r u i t ( 1 8 ) . I t has been found t h a t the e f f e c t o f l i g h t on a s c o r b i c a c i d f o r m a t i o n i s c u m u l a t i v e and depends on the t o t a l amount o f l i g h t absorbed by the f r u i t f rom the t ime o f f r u i t f o r m a t i o n u n t i l f r u i t m a t u r i t y ( 18 ) . F a c t o r s thought to a f f e c t the f i r m n e s s of tomatoes and o t h e r f r u i t s have been i n v e s t i g a t e d b y many workers over a c o n -s i d e r a b l e p e r i o d of t i m e . Appleman and Conrad (1) i n 1926 i n v e s t i g a t e d the r e l a t i o n -s h i p o f w a t e r - s o l u b l e p e c t i n , a c i d - h y d r o l y z a b l e p e c t i n or p r o t o -p e c t i n , and t o t a l p e c t i n i n the f r u i t as i t o c c u r s d u r i n g the normal r i p e n i n g of p e a c h e s . They c o n c l u d e d t h a t , as r i p e n i n g p r o g r e s s e s accompanied by consequent s o f t e n i n g , p r o t o p e c t i n i s changed t o w a t e r - s o l u b l e p e c t i n a t a r a t e p a r a l l e l i n g the degree - 1 4 -o-f r i p e n i n g and s o f t e n i n g ; but t h a t , a t any s tage of r i p e -n i n g , the t o t a l p e c t i n remains a lmost c o n s t a n t . The same workers (2) i n 1927 i n v e s t i g a t e d the r e l a t i o n s h i p o f p e c t i c s u b s t a n c e s to the degree of r i p e n i n g and s o f t e n i n g of f r e s h tomatoes . They c o n c l u d e d t h a t , as f r e s h tomatoes r i p e n f rom green to f u l l r i p e w i t h consequent s o f t e n i n g , p r o t o p e c t i n i s c o n v e r t e d to w a t e r - s o l u b l e p e c t i n b u t , as i n the case o f p e a c h e s , the t o t a l p e c t i n remains a lmost c o n s t a n t . They a l s o c o r r e l a t e d the r a t i o o f w a t e r - s o l u b l e p e c t i n t o p r o t o p e c t i n w i t h the degree o f d i s i n t e g r a t i o n t h a t takes p l a c e d u r i n g the p r o c e s s i n g of whole tomatoes . They found t h a t as the p e c t i n -p r o t o p e c t i n r a t i o i n c r e a s e d the degree o f d i s i n t e g r a t i o n , as .measured by a s i e v e t e s t , a l s o i n c r e a s e d . T h e i r g e n e r a l c o n -c l u s i o n s were t h a t f i r m n e s s i n f r u i t i s dependent on the amount o f p r o t o p e c t i n p r e s e n t and t h a t , as p r o t o p e c t i n i s changed to w a t e r - s o l u b l e p e c t i n , p r o g r e s s i v e s o f t e n i n g of the f r u i t o c c u r s . In 1934, Degman and Weinberger (7) s t u d i e d the e f f e c t s of n i t r o g e n and p o t a s s i u m f e r t i l i z e r s on the f i r m n e s s and k e e p i n g q u a l i t i e s of a p p l e s and p e a c h e s . They c o n c l u d e d t h a t n i t r o g e n d i d not a f f e c t the f i r m n e s s o f e i t h e r f r u i t and t h a t , o f s e v e r a l p o t a s s i u m c o n t a i n i n g f e r t i l i z e r s , o n l y one t h a t a l s o c o n t a i n e d magnesium produced a f r u i t f i r m i n g e f f e c t . They a l s o conc luded t h a t p e c t i c m a t e r i a l s a re c l o s e l y r e l a t e d to f i r m n e s s and t h a t p r o t o p e c t i n s change to w a t e r - s o l u b l e p e c t i n s as r i p e -n i n g and s o f t e n i n g of f r u i t t akes p l a c e . - 1 5 -Krausche and G i l h e r t (20) i n 1936 i n v e s t i g a t e d the e f f e c t o f n i t r o g e n f e r t i l i z e r s on the f l e s h i n e s s and f i r m n e s s o f tomatoes . They conc luded t h a t , a l t h o u g h h i g h n i t r o g e n t rea tments r e s u l t e d i n f r u i t w i t h a lower r a t i o of f l e s h y w a l l m a t e r i a l t o c r o s s - s e c t i o n a r e a , the f r u i t s produced f rom h i g h n i t r o g e n t rea tments appeared t o be f i r m e r than those f rom low n i t r o g e n t r e a t m e n t s . S o r e n s o n and A l l e y (24) i n v e s t i g a t e d the r e l a t i o n s h i p of h i g h n i t r o g e n f e r t i l i z e r t r e a t m e n t s t o the a b i l i t y of g r e e n -wrap tomatoes t o w i t h s t a n d l o n g d i s t a n c e s h i p p i n g . They c o n -c l u d e d t h a t h i g h n i t r o g e n t rea tments had no adverse e f f e c t on the f i r m n e s s or s h i p p i n g q u a l i t i e s of t o m a t o e s . C a l c i u m i s commonly added t o c o m m e r c i a l l y p r o c e s s e d whole tomatoes to improve t h e i r f i r m n e s s . I t i s u s u a l l y added i n the form of c a l c i u m c h l o r i d e - s o d i u m c h l o r i d e t a b l e t s . G o u l d , D a v i s , K r a n t z and H e a l y (12) have r e p o r t e d t h a t the a d d i t i o n o f c a l c i u m c h l o r i d e to p r o c e s s e d tomatoes had s u f f i c i e n t f i r m i n g e f f e c t to r a i s e the q u a l i t y r a t i n g one U . S . g r a d e . Hamson (15) found t h a t c a l c i u m c h l o r i d e would i n c r e a s e the f i r m n e s s of s o f t tomatoes but had no a p p r e c i a b l e e f f e c t on tomatoes t h a t were a l r e a d y r e a s o n a b l y f i r m . K e r t e s z (19) s t a t e s t h a t , when c a l c i u m c h l o r i d e - s o d i u m c h l o r i d e t a b l e t s are added t o p r o c e s s i n g tomatoes , c a l c i u m combines w i t h demethy la ted p e c t i n to form a c a l c i u m p e c -t a t e g e l which produces the f i r m i n g e f f e c t u s u a l l y n o t e d . Hamson (15, 16) n o t e d t h a t c e r t a i n v a r i e t i e s of tomatoes a lways produced f i r m e r f r u i t s than o t h e r v a r i e t i e s grown under - 1 6 -I d e n t i c a l c o n d i t i o n s . He found t h a t the f r u i t s f rom the f i r m -f r u i t e d v a r i e t i e s always c o n t a i n e d a h i g h e r percen tage o f c a l c i u m than the f r u i t s f rom s o f t - f r u i t e d v a r i e t i e s showing t h a t some v a r i e t i e s a p p a r e n t l y had a g r e a t e r a b i l i t y to take up c a l c i u m f rom the same n u t r i e n t medium. He a l s o found t h a t f r u i t f rom f i r m - f r u i t e d v a r i e t i e s c o n t a i n e d more of the dem-e t h y l a t i n g enzyme, p e c t i n m e t h y l e s t e r a s e , than f r u i t f rom s o f t -f r u i t e d v a r i e t i e s . From t h i s work o f Hamson and t h a t of K e r t e s z (15 , 1 6 , 19) i t appears t h a t , when p e c t i n m e t h y l e s t e r a s e dem-e t h y l a t e s the p e c t i n i n t o m a t o e s , a c a l c i u m p e c t a t e g e l i s formed w h i c h has a f i r m i n g e f f e c t on the f r u i t and a l s o e s t a b -l i s h e s a c a l c i u m g r a d i e n t i n the p l a n t w i t h the r e s u l t t h a t a g r e a t e r amount of c a l c i u m i s taken up f rom the n u t r i e n t medium. Hamson (16) a l s o o b t a i n e d p o s i t i v e c o r r e l a t i o n s between w a t e r - s o l u b l e p e c t i n , a c i d - s o l u b l e p e c t i n , ammonium o x a l a t e -s o l u b l e p e c t i n and t o t a l p e c t i n w i t h f i r m n e s s of tomato f r u i t s as measured by a p r e s s u r e t e s t e r , p r o v i d e d t h a t the f r u i t s b e i n g t e s t e d were a t a comparable s tage o f r i p e n e s s . The l i t e r a t u r e rev iewed r e v e a l s t h a t the re are many i n f l u e n c e s t h a t a f f e c t the q u a l i t y o f tomato f r u i t . The c o l o r o f the f r u i t i s a f f e c t e d by v a r i e t y and tempera ture ( 6 , 8 , 9 , 1 7 , 22 , 2 5 ) . The s i z e and shape of the f r u i t a re a f f e c t e d by v a r i e t y and c u l t u r a l p r a c t i c e s (20, 2 4 ) . The f l a v o r of the f r u i t i s a f f e c t e d by v a r i e t y , s u n l i g h t and c u l t u r a l p r a c t i c e s (6 , 1 3 , 14 , 2 1 , 2 3 ) . The v i t a m i n G content o f the f r u i t i s - 1 7 -a f f e c t e d by v a r i e t y and l i g h t {14, 1 8 , 8 6 ) . The f i r m n e s s o f tomato f r u i t appears t o be r e l a t e d to c a l c i u m conten t (11 , 1 2 , 1 5 , 1 6 , 19) wh ich i n t u r n may be a f f e c t e d by v a r i e t y (15 , 16) and by n u t r i t i o n (10 , 1 1 ) . Tomato f r u i t f i r m n e s s a l s o appears t o be r e l a t e d t o p e c t i n c o n t e n t wh ich may be a f f e c t e d by v a r -i e t y (15 , 1 6 ) , m a t u r i t y ( 1 , 2 , 7 , 19) and c a l c i u m c o n t e n t (15 , 1 6 ) . The work of Hamson (15 , 16) s u g g e s t s t h a t , p r o v i d e d one tomato v a r i e t y i s c o n s i d e r e d a t a t ime and p r o v i d e d f r u i t s o f the same m a t u r i t y a r e u s e d , comparat ive a n a l y s i s of tomato f r u i t f o r any of the p e c t i c f r a c t i o n s w i l l r e v e a l d i f f e r e n c e s i n tomato f r u i t f i r m n e s s . I f such i s the c a s e , compara t ive a n a l y s i s f o r any of the p e c t i c f r a c t i o n s s h o u l d r e v e a l any e f f e c t on the f i r m n e s s of tomato f r u i t f rom t rea tments d e s i g n e d to a f f e c t f i r m n e s s . i -18-M ATE RIALS and METHODS 1955 P r e l i m i n a r y S u r v e y No d a t a ir«s^ a v a i l a b l e a t t h e s t a r t o f t h i s i n v e s t i g -a t i o n c o n c e r n i n g the n u t r i e n t s t a t u s o f tomato p l a n t s o r tomato-growing s o i l s i n the B.C. I n t e r i o r . A p r e l i m i n a r y s u r v e y was made, t h e r e f o r e , i n 1953 i n w h i c h samples of s o i l , tomato l e a v e s and tomato f r u i t were c o l l e c t e d f r o m s e l e c t e d tomato f i e l d s i n each d i s t r i c t i n the a r e a and a n a l y s e d a t the P l a n t N u t r i t i o n L a b o r a t o r y of the Summerland E x p e r i m e n t a l Farm. S o i l samples were t a k e n t o s i x and t w e l v e i n c h d e p t h s . They were s c r e e n e d t h r o u g h o n e - e i g h t h i n c h s c r e e n i n g t o remove r o c k s and d e b r i s , then e x t r a c t e d by the car b o n d i o x i d e method. The e x t r a c t s were a n a l y s e d by s t a n d a r d l a b o r a t o r y methods f o r pH, c o n d u c t i v i t y , phosphorus, c a l c i u m and magnesium. L e a f samples were t a k e n from r e c e n t l y matured s e c t i o n s of the p l a n t s . They were d r i e d , ashed, and then e x t r a c t e d w i t h f i v e p e r c e n t h y d r o c h l o r i c a c i d . They were a n a l y s e d by s t a n d a r d l a b o r a t o r y methods f o r n i t r o g e n , phosphorus, p o t a s s i u m , c a l c i u m , magnesium and boro n . F r e s h f r u i t samples were s e c t o r e d and f r o z e n , then d r i e d , a shed, and e x t r a c t e d w i t h f i v e p e r cent h y d r o c h l o r i c a c i d . They were a n a l y s e d f o r n i t r o g e n , phosphorus, p o t a s s i u m , c a l c i u m and magnesium by s t a n d a r d l a b o r a t o r y methods. -19-F r u i t samples were a l s o c o l l e c t e d and p r o c e s s e d as w h o le, canned tomatoes. They were p i c k e d a t the f u l l y r i p e s t a g e , and p r o c e s s e d by s t a n d a r d p r o c e s s i n g methods a t the F r u i t and V e g e t a b l e P r o c e s s i n g L a b o r a t o r y of the Summerland E x p e r i m e n t a l Farm. They were s t o r e d f o r two months and t h e n examined f o r f i r m n e s s and wholeness by e x p e r i e n c e d s t a f f members. 1954 F e r t i l i z e r E x p e r i m e n t s I n f o r m a t i o n o b t a i n e d f r o m t h e 1953 p r e l i m i n a r y s u r v e y i n d i c a t e d t h a t t h e r e was a d i f f e r e n c e i n q u a l i t y between p r o -c e s s e d tomato samples f r o m the Kelowna d i s t r i c t and t h o s e f r o m the Vernon and Kamloops d i s t r i c t s . There were a l s o d i f f e r e n c e s i n t h e l e v e l s o f c a l c i u m , p o t a s s i u m and magnesium i n s o i l , l e a f and f r u i t samples o b t a i n e d from t h o s e d i s t r i c t s . T h i s i n f o r m -a t i o n was used t o choose s i t e s i n those t h r e e d i s t r i c t s f o r a f e r t i l i z e r e xperiment i n w h i c h the e f f e c t s o f . s e v e r a l p l a n t n u t r i e n t s on the c o m p o s i t i o n o f tomato p l a n t s and on t h e q u a l i t y o f tomato f r u i t would be n o t e d . An e x p e r i m e n t a l p l a n was p r e p a r e d i n w h i c h s o i l t r e a t -ments o f b o r o n , manganese, magnesium, z i n c , c o p p e r , c a l c i u m , c a l c i u m p l u s boron and a n u t r i e n t m i x would be a p p l i e d i n a 9 x 5 randomized b l o c k d e s i g n as shown i n figure? 1. The same p l a n was used i n e ach o f the d i s t r i c t s of K elowna, Vernon and Kamloops. -20-Block I 2 3 7 9 14 8 6 l Block I I 1 k 2 8 5 9 6 3 7 Block I I I 6 8 1 3 U 7 5 2 9 Block IV 7 6 2 1 3 8 U Block V 5 7 9 l 3 8 2 h 6 F i g . 1. Bandomized 9 x 5 Block Arrangement Used at the Three Experiment Locations. -21-E a c h o f the n i n e t r e a t m e n t s was g i v e n a number and t h i s same numbering s y s t e m was used a t t h e t h r e e l o c a t i o n s . The t r e a t m e n t s , w i t h t r e a t m e n t numbers, n u t r i e n t element c o n c e r n e d , m a t e r i a l used t o s u p p l y t h e n u t r i e n t element and p e r a c r e a p p l i c a t i o n r a t e s o f t h e m a t e r i a l s s u p p l y i n g t h e n u t r i e n t s , were as f o l l o w s : Treatment 1 Rate No. Element M a t e r i a l Used (Lb. p e r a c r e ) 1 Boron Sodium t e t r a b o r a t e SO 2 Manganese Manganese s u l p h a t e 20 3 Magnesium Magnesium s u l p h a t e 40 4 Z i n c Z i n c s u l p h a t e 20 5 Copper Copper s u l p h a t e 20 6 C a l c i u m C a l c i u m s u l p h a t e 1000 7 Ca. + B. No. 1 + No. 6 1020 8 M i x Nos. 1 t o 6 mixed 1120 9 Check No Treatment W i t h t h e e x c e p t i o n o f t h e c a l c i u m s u l p h a t e t r e a t m e n t , e a c h t r e a t m e n t m a t e r i a l was d i s s o l v e d i n w a t e r and a p p l i e d t o the d e s i g n a t e d p l o t a r e a s from a w a t e r i n g c a n. C a l c i u m s u l -phate was s p r e a d i n the d r y f o r m . I n a d d i t i o n t o t h e s e t r e a t -ments, e a c h p l o t a r e a was f e r t i l i z e d w i t h 8-10-5 f e r t i l i z e r a t t h e r a t e of 500 pounds p e r a c r e . A f t e r a l l t r e a t m e n t s were a p p l i e d , t h e s o i l i n each p l o t a r e a was c u l t i v a t e d t o m i x the t r e a t m e n t m a t e r i a l s i n t o r o o t d e p t h . E a c h t r e a t m e n t p l o t c o n t a i n e d s i x t e e n t e s t p l a n t s o f C l a r k ' s E a r l y v a r i e t y p l a n t e d f o u r f e e t a p a r t i n a 4 x 4 p a t -•22-t e r n . Guard rows s e p a r a t e d each t r e a t m e n t p l o t from o t h e r t r e a t m e n t p l o t s . L e a f samples were c o l l e c t e d f r o m t h e p l o t s I n m i d -season. They were d r i e d , ashed, e x t r a c t e d w i t h f i v e p e r cent h y d r o c h l o r i c a c i d and a n a l y s e d by s t a n d a r d l a b o r a t o r y methods f o r phosphorus, p o t a s s i u m , magnesium and boro n . A f o u r pound sample of f i r m mature f r u i t was s e l e c t e d a t random from each p l o t i n mid-September. E a c h f r u i t was s e c -t o r e d and enough s e c t o r s were taken t o f i l l a p i n t - s i z e d f r e e z e r c a r t o n . The c a r t o n s o f f r u i t s e c t o r s were f a s t f r o z e n a t com-m e r c i a l f r e e z i n g e s t a b l i s h m e n t s i n t h e l o c a l i t y and t h e n t r a n s -p o r t e d t o the Summerland E x p e r i m e n t a l Farm where t h e y were s t o r e d a t 0° F. Because the work o f Hamson ( 1 5 , 16) and o t h e r s ( 1 , 2, 7, 19) i n d i c a t e d t h a t p e c t i n was a s s o c i a t e d w i t h t h e q u a l i t y of f i r m n e s s of tomatoes and o t h e r f r u i t s , and because Hamson's work (15) i n d i c a t e d t h a t c o m p a r a t i v e l e v e l s o f w a t e r - s o l u b l e p e c t i n c o u l d be used as a measure o f c o m p a r a t i v e f i r m n e s s o f tomatoes, the f r o z e n samples of tomato f r u i t f r o m the t r e a t -ment p l o t s were a n a l y s e d f o r w a t e r - s o l u b l e p e c t i n . I t was hoped t h a t any d i f f e r e n c e s i n w a t e r - s o l u b l e p e c t i n found i n f r u i t from p l o t s under v a r i o u s t r e a t m e n t s c o u l d be used t o det e r m i n e t h e e f f e c t , i f any, t h a t the n u t r i e n t t r e a t m e n t s had on the q u a l i t y o f f i r m n e s s of the tomato f r u i t . -23-W a t e r - s o l u b l e p e c t i n c o n t e n t o f the tomato samples was d e t e r m i n e d by a m o d i f i c a t i o n o f C a r r e and Haynes method (5) as used by M c l n n e y of the Food and Drug L a b o r a t o r i e s , D i v i s i o n o f C h e m i s t r y , C e n t r a l E x p e r i m e n t a l Farm a t Ottawa. The f r o z e n samples were thawed, then macerated and mixed i n a Waring B l e n d o r . D u p l i c a t e a l i q u o t s o f 100 gm. each were d i l u t e d w i t h 400 m l . of d i s t i l l e d w a t e r , b o i l e d f o r one hour and then f i l t e r e d . From t h e f i l t r a t e a 100 m l . a l i q u o t was made up t o 400 m l . w i t h d i s t i l l e d w a t e r ; 10 m l . I N NaOH was added and the s o l u t i o n s were a l l o w e d t o s t a n d o v e r n i g h t . The f o l l o w i n g m o r n i n g , 50 m l . o f I N a c e t i c a c i d was added; t h e s o l u t i o n s were a l l o w e d t o s t a n d f o r f i v e m i n u t e s , t h e n 50 m l . of I N c a l c i u m c h l o r i d e was added and the s o l u t i o n s were a l l o w e d t o s t a n d f o r one hour. The s o l u t i o n s were t h e n heated t o b o i l i n g f o r one minute and the n f i l t e r e d t h r o u g h #41 Whatman f i l t e r p a p e r s . The j e l l y - l i k e p r e c i p i t a t e t h a t c o l l e c t e d on the f i l t e r p a pers was washed w i t h n e a r - b o i l i n g w a t e r u n t i l f r e e from c h l o r i d e s . I t was t h e n washed i n t o a weighed aluminum d r y i n g can and d r i e d f i r s t over a w a t e r b a t h and the n o v e r n i g h t i n a d r y i n g oven a t 100° C. I n the m o r n i n g , the cans were rem-oved from t h e d r y i n g oven, c o o l e d i n a d e s i c c a t o r , and t h e n weighed. The w e i g h t o f t h e d r y p r e c i p i t a t e was c a l c u l a t e d by s u b t r a c t i o n and c o n s i d e r e d t o be c a l c i u m p e c t a t e or w a t e r -s o l u b l e p e c t i n . C a l c u l a t i o n s were th e n r e c o r d e d on the b a s i s o f w a t e r - s o l u b l e p e c t i n p e r 100 gm. o f o r i g i n a l tomato f r u i t m a t e r i a l . -24 1955 Phosphorus E x p e r i m e n t A s e p a r a t e p r e l i m i n a r y i n v e s t i g a t i o n i n t o the e f f e c t o f n i t r o g e n , phosphorus and p o t a s s i u m on the y i e l d o f B.C. I n t e r i o r tomatoes had i n d i c a t e d t h a t b o t h n i t r o g e n and phosphorus i n -c r e a s e d y i e l d s . There was a l s o an i n d i c a t i o n t h a t phosphorus produced a b e n e f i c i a l e f f e c t on f r u i t q u a l i t y . To f u r t h e r t e s t t h i s e f f e c t , a phosphorus e x p e r i m e n t was c a r r i e d out a t Vernon i n 1955. Superphosphate (0-19-0) was a p p l i e d to t e s t p l o t s a t r a t e s t o s u p p l y 0, 100, 200 and 300 pounds o f P g 0 5 p e r a c r e . E a c h t r e a t m e n t was r e p l i c a t e d s i x t i m e s i n a 4 x 6 randomized b l o c k . The e n t i r e b l o c k was f e r t i l i z e d w i t h ammonium n i t r a t e (33-0-0) a t a r a t e t o s u p p l y 80 pounds of n i t r o g e n per a c r e . The b l o c k was c u l t i v a t e d to m i x the f e r t i l i z e r m a t e r i a l s i n t o r o o t d e p t h . E a c h t r e a t m e n t p l o t c o n t a i n e d s i x t e e n t e s t p l a n t s o f C l a r k ' s E a r l y v a r i e t y p l a n t e d f o u r f e e t a p a r t i n a 4 x 4 p a t -t e r n . Guard rows s e p a r a t e d each t r e a t m e n t p l o t from o t h e r t r e a t m e n t p l o t s . L e a f samples were c o l l e c t e d from the p l o t s i n m i d -season. They were d r i e d , a s h e d, e x t r a c t e d w i t h f i v e per cent h y d r o c h l o r i c a c i d and a n a l y s e d by a s t a n d a r d l a b o r a t o r y method f o r phosphorus. Samples of f u l l y r i p e f r u i t were p i c k e d a t random f r o m each t r e a t m e n t p l o t i n mid-September. These were p r o c e s s e d as whole canned tomatoes under s t a n d a r d p r o c e s s i n g c o n d i t i o n s by - 2 5 -the F r u i t and Vegetable Processing Laboratory of the Suimerland Experimental Farm. The canned samples were stored for two months and then opened and judged for wholeness and firmness by an experienced panel of the F r u i t and Vegetable Processing Lab-oratory s t a f f . Results were recorded as mean points f o r each treatment out of a possible f o r t y - f i v e points. -26-\ RESULTS 195S Preliminary Survey When the samples of processed tomatoes from the various d i s t r i c t s were examined for the q u a l i t i e s of firmness and whole-ness, i t was the unanimous opinion of the judging panel that the firmest samples were those from the Kelowna d i s t r i c t and the softest samples were those from the Vernon and Kamloops d i s t r i c t s . The nutrient status of s o i l , l e a f and f r u i t samples from those d i s t r i c t s then became of immediate i n t e r e s t as a source of information to explain the contrasts i n f r u i t q u a l i t y . A n a l y t i c a l r e s u l t s from s o i l , l e a f and f r u i t samples from f i e l d s within those d i s t r i c t s that were selected as s i t e s for a f e r t -i l i z e r experiment i n 1954 are presented in. tables 1, 2 and 3. TABLE 1. ANALYSIS OF SOIL SAMPLES TAKEN IN 1953 FROM SITES USED FOR FERTILIZER EXPERIMENTS IN 1954. L o c a l i t y PH Cond. P p.p.m. K p.p.m. Ca p.p.m. Mg p.p.m. Kelowna 7.8 55 33.77 38.75 1210 265.5 Vernon 6.8 471 36.55 115.00 275 50.5 Kamloops 8.0 173 10.04 123.75 1450 336.2 -27-I t w i l l be noted from table 1 that there was consider-able v a r i a t i o n i n s o i l analyses between the three l o c a l i t i e s . S o i l pH at Kelowna and Kamioops was considerably higher than i t was at Vernon. This appears to correlate with l e v e l s of calcium and magnesium at those l o c a l i t i e s . Conductivity was highest at Vernon and lowest at Kelowna. This may be r e l a t e d , i n part, to l e v e l s of potassium, but could also be related to the presence of other minerals such as sodium that were not determined. Phos-phorus l e v e l s were si m i l a r at Kelowna and Vernon and lower at Kamloops. Potassium l e v e l s were considerably higher at Vernon and Kamloops than they were at Kelowna. This appears to be the f i r s t instance i n which there was a d e f i n i t e difference between the two l o c a l i t i e s that produced the poorest f r u i t and the l o c -a l i t y that produced the best f r u i t . Calcium and magnesium were both considerably lower at Vernon than at either Kelowna or Kamloops. TABLE 2. ANALYSIS OF TOMATO LEAF SAMPLES TAKEN IN 1953 FROM SITES USED FOR FERTILIZER EXPERIMENTS IN 1954. (dry weigh b basis) L o c a l i t y N fo P % K * Ca * Mg * B P.p.m. Kelowna 3.21 .252 1.81 6.90 .779 91 Vernon 3.60 .390 3.88 4.70 .321 108 Kamloops 3.33 .205 2.15 6.00 1.060 51 -28-Data from analysis of tomato l e a f samples coll e c t e d at Kelowna, Vernon and Kamloops are presented i n table 2. N i t -rogen l e v e l s did not vary gre a t l y between the three l o c a l i t i e s . Phosphorus was higher at Vernon than at Kelowna or Kamloops. Potassium was much higher at Vernon than at Kelowna. Calcium was higher at Kelowna and Kamloops than at Vernon. Magnesium was highest at Kamloops, next highest at Kelowna and lowest at Vernon. Boron l e v e l s were i n a sim i l a r range at Kelowna and Vernon but lower at Kamloops. TABLE 3. ANALYSIS OF TOMATO FRUIT SAMPLES TAKEN IN 1953 FROM SITES USED FOR FERTILIZER EXPERIMENTS IN 1954. L o c a l i t y N P K Ca Mg * * * % * Kelowna 2.28 .377 3.02 .232 .103 Vernon 2.53 .462 4.12 .175 .115 Kamloops 2.73 .289 3.56 .136 .134 Data from analysis of f r u i t samples collected at Kelowna, Vernon and Kamloops are presented i n table 3. Nitrogen l e v e l s were sim i l a r i n the samples from the three l o c a l i t i e s . Phos-phorus was highest i n the Vernon samples. Potassium also was highest i n the Vernon samples. Calcium was highest i n the Kelowna samples. Magnesium l e v e l s were s i m i l a r i n samples from the three l o c a l i t i e s . The d a t a t h a t appear i n t a b l e s 1, 2 and 3 d i d n o t s u p p l y a r e a d i l y apparent r e a s o n why tomato f r u i t samples f r o m Kelowna were b e t t e r fchan those f r o m Vernon o r Kamloops. There appeared t o be a d e f i n i t e c o n t r a s t between Kelowna and Vernon i n t h a t samples from Kelowna were l o w i n p o t a s s i u m and h i g h i n c a l c i u m and magnesium w h i l e samples from Vernon were h i g h i n p o t a s s i u m and low i n c a l c i u m and magnesium. The c o n t r a s t d i d n o t h o l d w i t h the Kamloops samples w h i c h were r e l a t i v e l y h i g h i n p o t a s s i u m , c a l c i u m and magnesium. 1954 F e r t i l i z e r E x p e r i m e n t s T a b l e s 4, 5 and 6 p r e s e n t the r e s u l t s of a n a l y s i s o f tomato l e a f m a t e r i a l from t h e f e r t i l i z e r e x p e r i m e n t b l o c k s a t Kelowna, Vernon and Kamloops. Each v a l u e g i v e n i s the average o f f i v e r e p l i c a t e samples f r o m e a c h t r e a t m e n t . TABLE 4. ANALYSIS OF TOMATO LEAF MATERIAL FROM TBE KELOWNA FERTILIZER EXPERIMENT. Treatment Element P K Mg B Mn. A p p l i e d fo * « p.p.m. 1 B .232 .865 1.183 107 2 Mn .223 .745 1.088 46 3 Mg .241 .950 1.118 54 4 Zn. .232 .979 1.161 41 5 Cu .211 .700 1.174 49 6 Ca .222 1.015 1.190 51 7 Ca + B .227 .775 1.156 98 8 M i x .231 .810 1.245 104 9 Check .236 .855 1.162 59 -30-I t w i l l be n o t e d from the d a t a i n t a b l e 4 t h a t b oron was t h e o n l y a n a l y s e d element t h a t was a f f e c t e d by the f e r t i l -i z e r t r e a t m e n t s a t Kelowna; Each t r e a t m e n t t h a t c o n t a i n e d boron r e s u l t e d i n p r a c t i c a l l y d o u b l i n g the boron c o n t e n t o f the tomato l e a v e s . TABLE 5. ANALYSIS OF TOMATO LEAF MATERIAL FROM THE VERNON FERTILIZER EXPERIMENT. Treatment Element P K Mg B No. A p p l i e d 1° ' fo fo p.p.m. 1 B .357 2.66 1.000 55 2 Mn .346 2.80 .930 31 3 Mg .346 2.79 .953 25 4 Zn .333 2.90 .900 28 5 Cu .350 2.94 .955 34 6 Ca .323 2.89 1.047 20 7 Ca -f- B .352 2.93 .950 63 8 M i x .362 2.53 .984 64 9 Check .344 2.89 1.137 34 D a t a p r e s e n t e d i n t a b l e 5 i n d i c a t e t h a t boron was the. o n l y a n a l y s e d element a f f e c t e d by t h e f e r t i l i z e r t r e a t m e n t s a t Vernon. The boron c o n t e n t of tomato l e a v e s was p r a c t i c a l l y d o u b l e d by each t r e a t m e n t t h a t i n c l u d e d b o r o n . -31-TABLE 6. ANALYSIS OF TOMATO LEAF MATERIAL FROM THE KAMLOOPS FERTILIZER EXPERIMENT. Treatment Element P K Mg * B No. A p p l i e d 1o * p.p.m. 1 B .242 2.10 1.201 71 2 Mn .210 2.26 1.217 17 3 Mg .226 2.06 1.221 21 4 Zn .231 2.34 1.166 23 5 Cu .209 2.06 1.243 19 6 Ca .248 2.18 1.196 24 7 Ca + B .217 2.11 1.254 59 8 M i x ' .233 2.28 1.218 54 9 Check .238 2.07 1.225 20 D a t a p r e s e n t e d i n t a b l e 6 i n d i c a t e t h a t boron was the o n l y element a f f e c t e d by the f e r t i l i z e r t r e a t m e n t s a t Kamloops. The boron c o n t e n t o f tomato l e a v e s was d o u b l e d by each t r e a t -ment t h a t i n c l u d e d boron. D a t a p r e s e n t e d i n t a b l e s 2, 4, 5 and 6 show t h a t compar-a t i v e l e v e l s o f phosphorus, p o t a s s i u m and magnesium i n l e a f samples from the t h r e e e x p e r i m e n t a l s i t e s were s i m i l a r i n 1953 and 1954. I n b o t h y e a r s , phosphorus l e v e l s were h i g h e s t a t Vernon, p o t a s s i u m l e v e l s were h i g h e s t a t Vernon and l o w e s t a t Kelowna, and magnesium l e v e l s were h i g h e s t a t Kamloops and l o w e s t a t Vernon. I n 1954, boron c o n t e n t o f tomato l e a v e s was s i g n i f i c -a n t l y i n c r e a s e d a t each of the e x p e r i m e n t a l s i t e s by t r e a t m e n t s c o n t a i n i n g b o r o n . The r e s u l t s o f w a t e r - s o l u b l e p e c t i n a n a l y s e s o f f r u i t samples from f e r t i l i z e r t r e a t m e n t p l o t s a t Kelowna, Vernon and Kamloops a r e p r e s e n t e d i n t a b l e s 7, 8, .9 and 10. Table 7 p r e -s e n t s a summary of the mean w a t e r - s o l u b l e p e c t i n c o n t e n t o f f r u i t from each t r e a t m e n t i n . t h e t h r e e d i s t r i c t s and a l l o w s comparison o f t h e g e n e r a l mean w a t e r - s o l u b l e p e c t i n c o n t e n t s o f f r u i t f r o m t h e t h r e e e x p e r i m e n t a l b l o c k s . The r e s u l t s o f t r e a t -ment r e p l i c a t e s f o r each d i s t r i c t a r e p r e s e n t e d i n t a b l e s 8, 9 and 10. I t w i l l be n o t e d from t a b l e Z t h a t t h e r e was a s i g n i f i c a n t d i f f e r e n c e between the g e n e r a l mean p e c t i n c o n t e n t i n tomato f r u i t from the Kelowna d i s t r i c t compared t o the g e n e r a l mean pec-t i n c o n t e n t s o f f r u i t f r o m e i t h e r Vernon o r Kamloops, but t h a t t h e r e was no s i g n i f i c a n t d i f f e r e n c e between the g e n e r a l means o f Vernon and Kamloops. Data i n t a b l e s 8, 9 and 10 show t h a t t h e r e was no s i g n i f -i c a n t e f f e c t o f any o f the t r e a t m e n t s on w a t e r - s o l u b l e p e c t i n c o n t e n t o f tomato f r u i t a t any of t h e t h r e e l o c a l i t i e s . A l a r g e amount of v a r i a t i o n i s apparent between a n a l y s e s o f r e p l i c a t e s f r o m t h e same t r e a t m e n t s . T h i s f a c t u n d o u b t e d l y a f f e c t e d the degree o f d i f f e r e n c e r e q u i r e d f o r s t a t i s t i c a l s i g n i f i c a n c e . I t may be noted t h a t t h e g r e a t e s t apparent e f f e c t on w a t e r - s o l u b l e p e c t i n was o b t a i n e d f r o m t r e a t m e n t s c o n t a i n i n g c a l c i u m a t Kelowna; b o r o n , z i n c , copper, and c a l c i u m p l u s b oron a t Vernon; and manganese, c a l c i u m and c a l c i u m p l u s boron a t Kamloops. I t i s a p p a r e n t t h a t t h e e f f e c t of l o c a l i t y was g r e a t e r than t h e e f f e c t of any of the f e r t i l i z e r t r e a t m e n t s t h a t were used. -33-TABLE 7. THE EFFECT OF FERTILIZER TREATMENTS ON THE WATER-SOLUBLE PECTIN CONTENT OF FIELD TOMATOES AT THREE LOCATIONS IN THE B.C. INTERIOR. Treatment No. Water-soluble pectin. mg./lOOg.fresh f r u i t Treatment Kelowna Vernon Kamloops 1 Boron 33.2 26.2 22.0 2 Manganese 32.8 22.6 25.0 3 Magnesium 34.0 19.4 82.0 4 Zinc 32.0 24.8 22.2 5 Copper 33.8 24.8 20.2 6 Calcium 36.8 22.8 27.0 7 Ca. + B 38.2 25.4 24.4 8 Mix 39.2 22.6 24.2 9 Check 35.0 21.2 18.6 D i s t r i c t means 35.0 23.3 22.8 L.S.D. between d i s t r i c t means (P = 0.01) = 3.06 mg./lOOg -34-TABLE 8. KELOWNA EXPERIMENT. WATER - SOLUBLE PECTIN RECOVERED AS CALCIUM PECTATE. (mg./lOO g. f r u i t m a t e r i a l I Treatment No. R e p l i c a t i o n s r Treatment t o t a l s Treatment means 1 2 3 4 5 1 21 33 35 37 40 166 33.2 2 40 35 35 29 25 164 32.8 3 34 36 38 35 27 170 34.0 4 42 32 32 29 25 160 32.0 5 38 36 35 35 25 169 33.8 6 45 38 33 39 29 184 36.8 7 47 31 35 37 41 191 38.2 8 44 36 42 36 38 196 39.2 9 36 30 28 45 36 175 35.0 T o t a l s 347 307 313 322 286 1575 Means 38.5 34.1 34.7 35.7 31.7 175 35.0 L.S.D. between t r e a t m e n t means (P • 0.05) = 7.16 mg./lOOg. --35-TABLE 9. VERNON EXPERIMENT. WATER-SOLUBLE PECTIN RECOVERED ' AS CALCIUM PEC TATE. (mg./lOO g. f r u i t m a t e r i a l Treatment No. i R e p l i c a t i o n s Treatment ' t o t a l s Treatment means i 2 $ 4 5 1 25 34 32 23 17 131 26.2 2 26 32 18 14 23 113 22.6 3 17 10 51 18 21 97 19.4 4 26 29 22 22 E5 124 24.8 5 27 28 21 22 26 124 24.8 6 32 26 24 20 IS 114 22.8 7 36 17 24 37 13 127 25.4 8 14 I 9 33 26 21 113 22.6 9 32 16 IE 21 25 106 21.2 T o t a l s 235 211 S17 203 183 1045 Means 26.1 23.4 24.1 22.5 20.3 116.5 23.3 L.S.D. between t r e a t m e n t means (j? = 0.05) = 9.32 mg./100'g. -36-TABLE 10. KAMLOOPS EXPERIMENT. WATER - SOLUBLE PECTIN RECOVERED AS CALCIUM PEC TATE. fmg./lOO g. f r u i t m a t e r i a l ) Treatment B e t l i c a t i o n s Treatment Treatment No. i 2 3 4 5 t o t a l s means 1 25 37 20 15 13 110 22.0 2 37 19 36 16 17 125 25.0 3 22 35 20 22 11 110 22.0 4 18 27 28 16 22 111 22.2 5 19 29 25 15 13 101 20.2 6 18 31 21 38 27 135 27.0 7 19 38 22 23 20 122 24.4 8 23 21 24 33 20 121 24.2 9 13 20 20 24 16 93 18.6 T o t a l s o 194 257 216 202 159 1028 Means 21.5 28.5 24.0 22.4 17.6 114.2 22.8 L.S.D. between t r e a t m e n t means (P = 0.05) = 8.85 mg./lOO g. -37-1955 Phosphorus E x p e r i m e n t D a t a from t h e phosphorus e x p e r i m e n t c a r r i e d out a t Vernon i n 1955, a t a s i t e d i f f e r e n t from the one used f o r the Vernon f e r t i l i z e r e x p e r i m e n t i n 1954, a re p r e s e n t e d i n t a b l e 11. The i n i t i a l i n t e r e s t i n t h i s e x p e r i m e n t had been p r i m -a r i l y concerned w i t h t h e e f f e c t of i n c r e a s i n g i n c r e m e n t s o f phosphorus on tomato y i e l d . No s i g n i f i c a n t e f f e c t on y i e l d was o b t a i n e d , but a s i g n i f i c a n t i n c r e a s e i n t h e f i r m n e s s o f tomato f r u i t a f t e r p r o c e s s i n g was o b t a i n e d f r o m t r e a t m e n t s w i t h i n c r e a s i n g r a t e s o f phosphorus. The d a t a i n t a b l e 11 show t h a t , as t r e a t m e n t r a t e s o f phosphorus i n c r e a s e d , t h e r e was a d e f i n i t e i n c r e a s e i n the amount o f phosphorus p r e s e n t i n tomato l e a f t i s s u e . T h i s e f f e c t was h i g h l y s i g n i f i c a n t a t the r a t e of 200 pounds P o 0 pe r a c r e . The e f f e c t appeared to be l e v e l l i n g out a t t h a t r a t e because the n e x t 100 pound i n c r e m e n t produced o n l y a s l i g h t i n c r e a s e i n l e a f phosphorus. The d a t a i n t a b l e 11 a l s o show t h a t , as t r e a t m e n t r a t e s of phosphorus i n c r e a s e d , t h e r e was a d e f i n i t e i n c r e a s e i n the f i r m n e s s r a t i n g s o f p r o c e s s e d tomato samples from the t r e a t m e n t p l o t s . A s i g n i f i c a n t i n c r e a s e i n f i r m n e s s was o b t a i n e d f r o m the r a t e o f 100 pounds P2O5 P e r a c r e and t h e f i r m n e s s r a t i n g s con-t i n u e d t o i n c r e a s e t h r o u g h the 300 pound P2O5 p e r a c r e r a t e . I t s h o u l d be n o t e d t h a t the l e a f phosphorus l e v e l of the u n t r e a t e d p l o t s i n t h i s e x p e r i m e n t was c o n s i d e r a b l y l o w e r t h a n the l e a f phosphorus l e v e l s a t a d i f f e r e n t s i t e i n Vernon i n -38-1953 and 1954 as recorded i n tables 2 and 5. The highest l e v e l of l e a f phosphorus obtained from the 300 pound P2O5 per acre treatment was s t i l l lower than l e a f phosphorus l e v e l s at the other s i t e i n Vernon. -39-TABLE 11. THE EFFECT OF PHOSPHORUS FERTILIZER TREATMENTS ON THE PHOSPHORUS LEVELS IN TOMATO LEAVES AND THE FIRMNESS RATING OF PROCESSED TOMATO FRUIT IN A PHOSPHORUS FERTILIZER FIELD EXPERIMENT CONDUCTED AT VERNON IN 1955. Treatment. Lb. PgOg per acre (from superphosphate 19%) Leaf phosphorus. $ of dry weight. Quality r a t i n g of canned tomatoes. Firmness score. 0 0.194 21.16 100 0.221 29.16 A 200 0.256 30.16 * 300 0.258 34.33 L.S.D. (P = 0.05) 0.034 6.58 L.S.D. (P = 0.01) 0.048 9.10 -40-DISCUSSION 1955 Preliminary Survey The preliminary survey of 1953 appeared to serve a useful purpose i n that i t revealed differences i n q u a l i t y of tomato f r u i t from d i f f e r e n t d i s t r i c t s i n the B.C. I n t e r i o r and also revealed that there were differences i n l e v e l s of plant nutrients i n the s o i l s of those d i s t r i c t s . The d i s t r i c t s chosen for further experiments were those that showed the greatest difference i n f r u i t q uality. F r u i t from other d i s t r i c t s covered i n the survey was of intermediate quality and consequently of l e s s i n t e r e s t than the two extremes. I t i s perhaps unfortunate that the q u a l i t y ratings given to the survey f r u i t samples were not based on an objective test that resulted i n a d e f i n i t e number of points for each sample such as those recorded i n the 1955 phosphorus experiment, but the methods of such a te s t were not worked out u n t i l l a t e r . However, the method of judging i n which the samples were rated good, f a i r or poor, was precise enough to separate the two quality extremes. The most i n t e r e s t i n g points derived from the survey sample analyses appeared to be that Kelowna, the d i s t r i c t pro-ducing the best tomato f r u i t q u a l i t y , was low i n potassium, high i n calcium and moderately well supplied with magnesium, -41-compared to Vernon which was high i n potassium, and low i n calcium and magnesium. Potassium i s widely promoted as a qu a l i t y producing element and i t has been applied to I n t e r i o r f i e l d tomatoes with the intent to improve tomato q u a l i t y , but i n t h i s survey the best quality tomatoes were produced i n s o i l r e l a t i v e l y low i n potassium, and the poorest quality tomatoes were produced i n s o i l r e l a t i v e l y high i n potassium. Most B.C. I n t e r i o r s o i l s are considered to be w e l l supplied with calcium, but Vernon appears to have considerably l e s s calcium than Kelowna or Kamloops. The low calcium content i n the Kamloops f r u i t sample appeared to be an anomaly consid-ering the amount of calcium i n the Kamloops s o i l and l e a f samples. 1954 F e r t i l i z e r Experiments The fact that boron treatments resulted i n 100 per cent increases i n the boron content of tomato leaves at the three experimental s i t e s , indicates the effectiveness of the boron-supplying material and the rates used. Whether or not the l e v e l s obtained as a res u l t of treatment are desirable i s not known. They appeared to produce an increase i n pectin content at Vernon and a s l i g h t increase when combined with calcium at Kelowna, but none at Kamloops. Magnesium treatments did not produce an increase i n le a f magnesium even at Vernon, the d i s t r i c t lowest i n magnesium. This suggests that the rates used were too low to produce an e f f e c t from the type of material used. -42-Results of the pectin analyses showed that the general mean level of pectin in tomato fruit was higher at Kelowna than at Vernon or Kamloops. This fact in conjunction with the observ-ation that tomato firmness was greater at Kelowna than at Vernon or Kamloops appears to substantiate Hamson*s statement (15) that water-soluble pectin content i s directly related to firmness of tomatoes. In that case, water-soluble pectin content should be a useful indicator to determine the effect of any treatment intended to increase the firmness of tomato f r u i t . The fact that no significant increase i n water-soluble pectin was obtained at any of the experimental sites from any of the f e r t -i l i z e r treatments used does not necessarily condemn the usefulness of water-soluble pectin as an indicator of tomato firmness. It may mean only that an effective treatment was not included in this experiment, or that the rates were not high enough to produce a significant effect. The fact that calcium treatments produced the most consistent increase in water-soluble pectin, in conjunction with the fact that the'Kelowna d i s t r i c t , which had high calcium levels, produced the firmest f r u i t and the fr u i t with the highest water-soluble pectin content agrees with Hamson*s statement (15) that firmness, calcium content and water-soluble pectin content are directly related in tomato f r u i t . -43-1955 Phosphorus Experiment The results of the 1955 phosphorus experiment are inter-esting because a definite increase in tomato firmness was obtained from a f e r t i l i z e r treatment. The data suggest that the increase in firmness was the result of an increased uptake of phosphorus by the plants, but there are some hazards in that conclusion. In the experiment, phosphorus was supplied by superphos-phate which i s known to contain calcium as well as phosphorus. It i s possible that increased phosphorus intake was accompanied by increased calcium intake and that the increased calcium con-tent resulted in increased firmness of the f r u i t . No firm conclusions can be drawn from this experiment until further analysis of the plant material is made except that incre-asing increments of superphosphate f e r t i l i z e r resulted in increased firmness of the tomato f r u i t . -44-CONCLUSIONS Processed tomato f r u i t samples from the Kelowna d i s -t r i c t were firmer than samples from other d i s t r i c t s i n the B.C. I n t e r i o r . Processed tomato f r u i t samples from the Vernon and Kamloops d i s t r i c t s were softer than samples from other d i s -t r i c t s i n the B.C. I n t e r i o r . Samples of s o i l , tomato l e a f material and tomato f r u i t from the Kelowna d i s t r i c t were r e l a t i v e l y high i n calcium, low i n potassium and moderately high i n magnesium. Samples of s o i l , tomato l e a f material and tomato f r u i t from the Vernon d i s t r i c t were r e l a t i v e l y low i n calcium, high i n potassium and low i n magnesium. Samples of s o i l , tomato l e a f material and tomato f r u i t from the Kamloops d i s t r i c t were r e l a t i v e l y high i n calcium, high i n potassium and high i n magnesium. Frozen samples of fresh tomato f r u i t from the Kelowna d i s t r i c t contained a s i g n i f i c a n t l y higher percentage of water-soluble pectin than samples from Vernon or Kamloops. Treatments of boron, manganese, magnesium, zinc, copper and calcium, either s i n g l y or i n combination, f a i l e d to produce a s i g n i f i c a n t e f f e c t on the water-soluble pectin content of -45-tomatoes at Kelowna, Vernon or Kamloops, but the calcium treatments appeared to produce the most consistent increase i n water-soluble pectin. Increasing increments of superphosphate produced a s i g n i f i c a n t progressive increase i n the firmness of processed tomato samples at Vernon accompanied by a s i g n i f i c a n t increase i n tomato l e a f phosphorus. - 4 6 -SUMMAEY The data obtained i n this i n v e s t i g a t i o n suggest that firmness of B.C. I n t e r i o r tomatoes may be affected by calcium, phosphorus and potassium l e v e l s i n the s o i l . Calcium and phosphorus appeared to exert a b e n e f i c i a l e f f e c t on tomato firmness and high potassium l e v e l s appeared to be associated with lack of firmness. Water-soluble pectin content appeared to be d i r e c t l y associated with firmness of tomato f r u i t and, therefore, i t appears to o f f e r some usefulness as an indicator of tomato firmness, but further investigation i s required to determine i t s r e l i a b i l i t y as an accurate indicator of tomato firmness. -47-REFERENCES 1. Appleman, CO.,'and CM. Conrad. Pectic constituents of peaches and their r e l a t i o n to softening of the f r u i t . Maryland Agr. Expt. Sta., b u l l . no. 283. 1926. 2. Appleman, CO., and CM. Conrad. The pectic c o n s t i t -uents of tomatoes and t h e i r r e l a t i o n to the canned product. Maryland Agr. Expt. Sta., b u l l . no. 291. 1927. 3. B.C. Dept. of Agriculture. Control of t r e e - f r u i t pests and diseases. Farmer's information sheet. 1955. 4. B.C. Dept. of Agriculture. F e r t i l i z e r recommendations for Okanagan and main l i n e points. Farmer's inform-ation sheet. 1955. 5. Carre,. M.H. , and D. Haynes. The estimation of pectin as calcium pectate and the application of t h i s method to the determination of soluble pectin i n apples. Biochem. Jour. 16: 60-69. 1922. 6. Cruess, W.V. Commercial f r u i t and vegetable products. McGraw-Hill, New York. 1938. 7. Degman, E.S., and J.H. Weinberger. Studies on firmness and keeping quality of certain f r u i t s . Maryland Agr. Expt. Sta., b u l l . no. 366. 1934. 8. Denisen, E.L. Tomato color as influenced by v a r i e t y and environment. Proc. Amer. Hort. S c i . 51: 349-356. 1948. 9. Duggar, B.M. Lycopersicin, the red pigment of the tomato. Wash. Univ. Studies. 1913. 10. Evans, H.J., and H.Y. Troxler. Relation of calcium nut-r i t i o n to the incidence of blossom-end r o t i n tom-atoes. Proc. Amer. Soc. Hort. S c i . 61: 346-352. 1953. -48-11. Geraldson, CM., E.L. Spencer and M.C. Jorgenson. Chem-i c a l analysis as a tool i n determining n u t r i t i o n a l factors a f f e c t i n g tomato quality, proc. F l o r i d a State Hort. Soc. 67: 123. 1954. 12. Gould, W.A., R.B. Davis, F. Krantz, and N.C Healy. A study of the rel a t i o n s h i p s of various grades of fresh and canned vegetables. Ohio Agr. Expt. Sta., mimeo no. 53-1. 1953. 13. Gubbels, C P . The e f f e c t of photoperiod and s o i l nut-r i e n t l e v e l of nitrogen, phosphorus and potassium on the composition and growth of the tomato. M.S.A. Thesis. Univ. of B r i t i s h Columbia. 1954. 14. Hamner, K.C., L. Bernstein and L.A. Maynard. E f f e c t s of l i g h t i n t e n s i t y , day length, temperature, and other environmental factors on the ascorbic acid content of tomato f r u i t s . Jour. Nutr. 29: 85-97. 1945. 15. Hamson, A.R. Factors which condition firmness i n tomatoes, Food Research, 17: 4, 370. 1952. 16. Hamson, A.R. Measuring firmness of tomatoes i n a breeding program. Proc. Amer. Soc. Hort. S c i . 60: 425-433. 1952. 17. Hanson, J . Tomato color. The Canner, 52(4) 35-37. 1921. 18. Hassan, H.H., and J.P. McCollum. Factors a f f e c t i n g the content of ascorbic acid i n tomatoes. Univ. of I l l i n o i s Agr. Expt. Sta., b u l l . no. 573. 1954. 19. Kertesz, Z.J. The pectic substances. Interscience Pub-l i s h e r s , Inc. New York. 1951. 20. Krausche, K.K., and B.E. G i l b e r t . Variations i n f l e s h -iness of tomato f r u i t s as affected by f e r t i l i z a t i o n . Plant Phys. 11: 3. 641-645. 1936. 21. Magel, H.A. Some e f f e c t s of micronutrient elements upon certain enzymes, vitamin C content, and general meta-bolism of the tomato. M.S.A. Thesis. Univ. of B r i t i s h Columbia. 1955. --49-22. Sayre, C . B . , W.B. Robinson and T. Wishnetsky. E f f e c t of temperature on the color, lycopene and carotene content of detached and vine-ripened tomatoes. Proc. Amer. Soc. Hort. S c i . 61: 381-387. 1953. 23. Scott, L.E., and E.P. Walls. Ascorbic acid content and sugar-acid r a t i o s of fr e s h f r u i t and processed juice of tomato v a r i e t i e s . Proc. Amer. Soc. Hort. S c i . 50: 269-272. 1947. 24. Sorenson, H.B., and L.S. A l l e y . E f f e c t of d i f f e r e n t rates of nitrogen f e r t i l i z e r on the shipping quality of green wrap tomatoes. Texas Agr. Expt. Sta. Progress Rept. 1522. 1952. 25. Wright, R.C., et a l . E f f e c t of various temperatures on the storage and ripening of tomatoes. U.S. Dept. Agr. Tech. B u l l . no. 268.' 1931. 26. Yeager, A.F., and H.J". Purinton. Lycopersicon Peruvi-an urn as a parent i n the development of high ascorbic acid v a r i e t i e s . Proc. Amer. Soc. Hort. S c i . 48: 403-405. 1946. 

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