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Modification of the incidence of surface damage symptoms in sweet cherries by pre- and postharvest treatments Lidster, Perry David 1979

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MODIFICATION OF THE INCIDENCE OF SURFACE DAMAGE SYMPTOMS IN SWEET CHERRIES BY PRE- AND POSTHARVEST TREATMENTS by PERRY DAVID LIDSTER B. Sc. (Agr.) UNIVERSITY OF BRITISH COLUMBIA, 1972 M. Sc. UNIVERSITY OF BRITISH COLUMBIA, 1976 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES Department of Food Science We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA November 1978 T ) Perry David Lidster, 1978 In p r e s e n t i n g 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 o f the r e q u i r e m e n t s 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 C o l u m b i a , I ag ree tha t 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 r e f e r e n c e and s t u d y . I f u r t h e r ag ree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by the Head o f my Department o r by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department o f Food S c i e n c e The U n i v e r s i t y o f B r i t i s h C o l u m b i a 2075 Wesbrook Place Vancouver, Canada V6T 1W5 Date A p r i l 25, 1979. ABSTRACT The prevention of storage disorders in sweet cherries resulting from mechanical damage was investigated. Pre- and postharvest treatments were applied to modify f r u i t texture, fruit composition and fr u i t desiccation in storage. The effects of the treatments applied were related to frui t susceptibility to the incidence of frui t bruises, surface markings and surface pitting. The application of calcium in the form of preharvest sprays or postharvest dips decreased mechanical damage expression. Warm frui t was less susceptible to mechanical injury than cold f r u i t early in the storage period but fr u i t temperature had l i t t l e effect after 8 days of cold storage. Similarly, high storage temperatures enhanced pitting development early in the storage l i f e but storage temperatures o had negligible effect after 8 days. A delay in 0 C storage prior to bruising greatly reduced the susceptibility of cherries to mechanical injury. Fruit was most resistant to mechanical damage after 8 days in 0°C. The development of fr u i t symptoms in response to impact was enhanced by rough surfaces. Slowly applied compressive forces resulted in low incidences of injury symptoms. • Fruit firmness and bioyield values were increased with mesocarp calcium from preharvest sprays and postharvest dips, but did not show consistent relationships to the susceptibility of frui t to mechanical damage. Weight loss enhanced by low relative humidity increased the rate of development of damage but did not influence the total damage incidence. Soaking fruit in water or fungicide solution increased damage expression in storage. Less - i i i -mature- and intermediate maturity fruit were more susceptible to mechanical injury than were the most mature f r u i t . Fruit with relatively high alcohol insoluble solids content associated with preharvest gibberellic acid sprays or advanced maturity fru i t had reduced susceptibility to mechanical damage. Large fruit was less susceptible to mechanical damage and had higher alcohol insoluble solids content than did small f r u i t . High levels of f r u i t nitrogen were associated with high susceptibility to mechanical damage. A great many factors were found to modify fruit susceptibility to surface disorders resulting from mechanical damage. This provides a great f l e x i b i l i t y to producers and marketing agents to minimize f r u i t losses due to the effects of rough handling. - v -Tissue Fractionation and Analysis 21 Alcohol insoluble solids determination . . 21 Cellulose determination 21 Soluble pectin determination 22 Total pectin determination . . . .' 22 Calcium Spray Experiments 23 1977 Study 23 1978 Study 23 Calcium Dip Experiments 24 Calcium penetration study 24 Thickener effect on CaCl_ dip 25 1977 Dipping duration study 25 1978 Dipping duration study 26 Effects of pH of CaCl^ dipping solution on calcium uptake and disorder incidence 27 Effects of washing on effectiveness of postharvest dips 27 Effects of soaking on surface disorders 28 Delay Versus Calcium Dip Experiments 29 1977 Study 29 1978 Study 30 Gibberellic Acid Experiments 31 1977 Study. 31 1978 Study 31 Fruit Maturity Experiments 32 1977 Study 32 1978 Study 33 - v i -Effects of Fruit Size on Composition and Disorder Incidence 34 Maturity versus f r u i t size 34 Drop height versus f r u i t size 1977 study 34 Drop height versus f r u i t size 1978 study 34 Effects of Bruising Surface and Rate of Deformation . . . .35 Height of drop versus bruising surface 35 Deformation rate versus bruising surface 36 Fruit and Storage Temperature Effects on Damage Incidence..36 Fruit temperature study 1977 36 Storage temperature study 1977 37 Fruit temperature study 1978 37 Storage temperature study 1978 38 Effects of Storage Temperature and Humidity on the Incidence of Surface Disorders 38 Effects of Thinning on Fruit Characteristics and Resistance to Impact Damage 39 Microscopic Examinations 40 RESULTS AND DISCUSSION 41 Calcium Study 41 Rate of calcium penetration 41 Factors affecting calcium uptake 42 Effects of CaCl^ spray and postharvest dips on fru i t texture 44 Effects of CaCl application and delay in storage on damage disorder incidence 46 Factors affecting the efficacy of postharvest dips in preventing surface damage of f r u i t 49 - v i i -Effects of Storage Humidity and Water Loss on Surface Disorders Expression 50 Effects of Fruit and Storage Temperatures on Surface Disorder Incidence 53 Effects of Maturity on Fruit Composition 55 Histological Examinations of Disorder Incidence 57 Effects of Maturity on Impact Damage Expression 58 Effects of Work, Deformation and Loading Rate on Fruit Damage Incidence 59 Effects of Fruit Size on Fruit Composition and Damage Disorder Incidence 62 Effects of Preharvest Sprays on Fruit Composition and Incidence of Damage Disorders 64 Effects of Reducing Crop Load on Fruit Characteristics and Susceptibility to Mechanical Damage 65 SUMMARY AND RECOMMENDATIONS 67 LITERATURE CITED 72 TABLES 80 FIGURES 122 - v i i i -LIST OF TABLES Table Page 1 Yearly cherry claims and returns 80 2 Approximate cherry production handled by B.C. Tree Fruits Ltd 81 3 Effects of contact time with postharvest dip on calcium uptake by 'Van' cherries, 1978 crop 82 4 Effects of f r u i t delay in storage, CaC^ and thickener dip on disorder incidence in 'Van' cherries, 1977 crop 83 5 Effects of f r u i t delay in storage, CaCl_ and thickener dip on disorder incidence in 'Van' cherries, 1978 crop 84 6 Effects of pH of postharvest calcium chloride dip on calcium uptake by 'Van' cherries, 1978 crop 85 7 Effects of preharvest CaCl„ tree sprays on cherry mineral content, 1977 crop 86 8 Effects of dipping 'Van' cherries in a CaCl dip solution on f r u i t bioyield and f r u i t firmness. No thickener in dip, 1977 crop 87 9 Effects of dipping 'Van' cherries in a CaCl_ dip solution on f r u i t bioyield and f r u i t firmness. Thickener in dip, 1977 crop 88 10 Effects of CaCl^ tree sprays on cherry fr u i t firmness, 1977 crop 89 11 Effects of preharvest CaCl., tree sprays on the incidence of cherry fru i t disorders, 1977 crop 90 12 Effects of preharvest CaC^ tree sprays on the incidence of cherry f r u i t disorders, 1978 crop 91 - ix -13 Effects of pH and CaCl_ postharvest dip on disorder incidence in Van' cherries, 1978 crop 92 14 Effects of storage temperature of fruit and humidity on weight loss and disorder development in 'Van'cherries,1978 crop 93 15 Effects of washing on effectiveness of postharvest dips in preventing damage disorders in 'Van' cherries, 1978 crop 94 16 Effects of dipping duration on disorder incidence in 'Van'cherries,1978 crop 95 17 Effects of handling temperature of fru i t on disorder incidence in 'Van' cherries, 1977 crop 96 18 Effects of f r u i t temperature at time of bruising on disorder development in 'Van' cherries, 1978 crop 97 19 Effects of storage temperature and f r u i t storage time on incidence of storage disorders in 'Van' cherries, 1977 crop 98 20 Effects of storage temperature of 'Van' cherries on disorder development, 1978 crop 99 21 Effects of maturity and storage of 'Van' cherries on soluble solids, weight, titratable acidity and firmness, 1977 crop 100 22 Effects of maturity on fru i t characteristics in 'Van' cherries, 1978 crop 101 23 Effects of maturity of 'Van' cherries on dry weight and mesocarp mineral content on a fresh weight basis, 1977 crop 102 24 Effects of maturity of 'Van' cherries on mineral content of f r u i t mesocarp on a dry weight basis, 1977 crop 103 25 Effects of f r u i t maturity on f r u i t composition on a dry weight basis, 1978 crop 104 26 Effects of f r u i t maturity on f r u i t composition on fresh weight basis, 1978 crop 105 - X -27 Effects of maturity and work done on cherry fr u i t on the incidence of surface disorders, 1977 crop 106 28 Effects of maturity of 'Van' cherries on disorder incidence, 1978 crop 107 29 Effects of maturity and work done on frui t on soluble solids, titratable acids, firmness and bioyield in 'Van'cherries,1977 crop 108 30 Effects of height of drop of cherry and bruising surface on disorder incidence in 'Van' cherries, 1978 crop 109 31 Effects of deformation, loading rate and bruising surface on the incidence of surface disorders in 'Van' cherries, 1978 crop 110 32 Effects of cherry fru i t weight and work done on fru i t on the incidence of surface disorders 1977 crop I l l 33 Effects of cherry f r u i t weight and work done on fr u i t on the incidence of surface disorders, 1978 crop 112 34 Effects of fru i t size on mesocarp composition of 'Van' cherries on fresh weight basis, 1978 crop. • • 113 35 Effects of fr u i t size on mesocarp composition of 'Van' cherries on dry weight basis, 1978 crop. . .114 36 Effects of cherry f r u i t weight and maturity on storage disorders, 1977 crop 115 37 Effects of gibberellic acid and mobileaf sprays on cherry f r u i t disorders, 1977 crop 116 38 Effects of fr u i t maturity and preharvest gibberellic acid spray on the incidence of surface disorders in 'Van' cherries, 1978 crop 117 39 Effects of preharvest gibberellic acid spray on 'Van' cherry mesocarp composition on a fresh weight basis, 1978 crop 118 40 Effects of preharvest gibberellic acid spray on 'Van' cherry mesocarp composition on a dry weight basis, 1978 crop 119 - x i -41 Effects of fr u i t thinning on soluble solids, titratable acidity, f r u i t weight and texture of 'Van' cherry f r u i t , 1977 crop 120 42 Effects of f r u i t thinning on the incidence of surface disorders in 'Van' cherries, 1977 crop 121 - x i i -Figure LIST OF FIGURES Page 1 Typical surface pitting and surface markings in 'Van' cherry 122 2 Radial section of 'Van' cherry (slight injury), showing surface pitting and injured zone in the lower hypodermal cells (from reference 70) . . . .122 3 Effect of cherry production on estimated susceptibility to pitting 123 4 Probe attachment to Ottawa Texture Measuring System 124 5 Typical force-deformation curve of individual cherry pressure test 125 6 Moisture loss of sweet cherry flesh stored at 65°C 126 7 Calcium-45 Quench Correction Curve 127 8 Carbon-14 Energy Spectrum 128 9 Calcium-45 Energy Spectrum 129 10 Work done on cherry versus distance of free f a l l and f r u i t weight 130 11 Calcium uptake by 'Van' cherries. 131 12 Calcium penetration into 'Van' cherries 132 13 Calcium uptake by cherries from postharvest calcium chloride dips modified by thickener 133 14 Mesocarp calcium uptake by 'Van' cherries from a postharvest dip modified by surfactant and thickener 134 15 Effects of calcium chloride postharvest dip on flesh calcium uptake in 'Van' cherry 135 16 Mesocarp calcium versus bioyield in 'Van' cherries 136 - x i i i -17 Mesocarp calcium versus f r u i t firmness in 'Van' cherries . . 137 18 Micrograph of non-damaged No. 3 color maturity cherry tissue (x60) . . . .138 19 Micrograph of No. 3 color maturity cherry tissue immediately after impact (x60) 138 20 Micrograph of No. 3 color maturity cherry tissue showing damage 9 days after impact (x60) 139 21 Micrograph of non-damaged No. 33 color maturity cherry tissue (x750) 139 22 Micrograph of No. 33 color maturity cherry tissue immediately after impact (x750) 140 23 Micrograph of No. 33 color maturity cherry tissue showing damage 9 days after impact (x750) 140 24 Weight loss in 'Van' cherries due to relative humidity in storage 141 - xiv To my wife Carole and daughter Amanda who have suffered. - xy -ACKNOWLEDGEMENTS I am indebted to Dr. S.W. Porritt without whose guidance and suggestions this study would not have been completed. The advice of Drs. M.A. Tung, G.W. Eaton, W.D. Powrie, P.A. J o l l i f f e and E.L. Watson in providing direction and encouragement is gratefully acknowledged. Thanks to K. Muller, H. Raitt, P. Johnston, M. Yee, M. Beulah, R. Yada and L. Jones for their dedicated technical assistance throughout the duration of this study. Financial support was provided by the NRC Industrial Research Assistance Program, by the University of British Columbia, by the British Columbia Ministry of Agriculture and Agriculture Canada. - 1 -INTRODUCTION Market Losses Due to Poor Fruit Quality Claims by wholesalers and retailers against fresh cherries grown in British Columbia have risen to significant proportions in the last 5 years of cherry marketing. The claims have amounted to I. 55 million dollars over the last 5 crop years. Reductions of grower returns since 1974 due to claims resulting from poor f r u i t quality, have ranged from a low of 3.3% in 1977 to a high of 26.6% in 1976 (Table 1). These percentage claim figures are important when considered as increased production costs or reduced grower returns of 7.7, 10.7, II. 1, 1.9, and 7.3c/kg through the crop years of 1974 to 1978. Continuing poor f r u i t quality w i l l lower consumer confidence and increase the resistance of wholesalers to purchase cherries grown in British Columbia. In addition to direct losses due to damage claims the market dollar loss due to declining consumer preference for British Columbia cherries in incalculable. Also poor product quality early in a particular market year prevents price increases during mid and latter part of the season, further depressing returns to the grower. Continuing reductions in the annual 4 million dollar return from fresh cherries can be anticipated unless the causes of poor f r u i t quality are identified and remedied. - 2 -Factors Affecting Sweet Cherry Fruit Quality Poor appearance of the fr u i t due to the high incidence of surface disorders apparently caused by mechanical damage is a major cause of market discontent. Symptoms of rough handling may be observed as surface pitting (Fig. 1) (66, 70) or flattened bruises (18). Surface pitting and bruising can be caused by mechanical damage and are associated with pressure or impact forces (18, 39, 61, 70, 71). Bruises are flattened surfaces on the cherry generally accompanied by tissue discoloration underlying the point of damage (61). Fruit bruises are apparent immediately after impact but surface pitting may not be visible externally for several days after damage has occurred and w i l l develop readily in storage. Surface pitting or dimpling appears as one or more irregular depressions on the surface of the f r u i t and often develops in cold storage (Fig. 1). Cellular examination of the depression reveals interior layers of injured cells while the cells in the cherry epiderm and hypoderm are unaffected but have collapsed inward (Fig. 2) (2, 70). Cherry surface pitting appears after the f r u i t has been picked and placed in cold storage for a period of 3 to 21 days (M. Patterson, WSU, Pullman, Washington, unpublished results). The disorder appears in cold storage but incipient symptoms can be detected by microscopic examination in freshly harvested bruised fr u i t (N. Wade, CSIRO, Australia, unpublished data). Whereas damage to apple i s apparent as discolored bruises, when cherries are injured pitting occurs but tissue - 3 -discoloration i s masked by the red pigment. The injury which induces the pitting occurs at a l l stages of cherry handling (71). The damage sustained by the cherry w i l l accumulate through the procedures of picking, sorting, packing and shipping. In years of high susceptibility to pitting, some frui t lots sorted and packed with mechanical aids have had greater than 60 percent severe pitting (26). Factors Affecting Fruit Susceptibility to Surface Disorders Resulting From Mechanical Damage The incidence of cherry pitting varies among crop years (Fig. 3) among cultivars and among trees (70). Fig. 3 indicates that yearly fluctuations in crop production are closely correlated with the estimated f r u i t susceptibility to surface pitting. The 1973 crop year was an outstanding exception to the general rule with a very high crop production but resistance to surface pitting. However, the weather conditions in 1973 were very favorable for cherry production and may have provided the cherry crop with a resistance to surface pitting. Fig. 3 suggests that some of the yearly fluctuations in pitting susceptibility may be associated with varying crop yields. This relationship may explain noticeable grower, tree, and lot variations where differences in crop production or percentage of the total crop is apparent. - 4 -There are a number of associated factors involved with high incidences of surface pitting in years of large crops. Trees heavily laden with fru i t may produce cherries with lesser amounts of photosynthate per f r u i t than a tree with a lighter crop (3). The reduced input of photosynthate and minerals to the developing fruits may result in inherently weaker cellular structures and may predispose the fru i t to mechanical damage. Also in heavy crop years the large volume of fru i t to be marketed may result in additional delays between packing and marketing which allows greater expression of surface pitting. Growers with a large crop to harvest may begin harvesting f r u i t at an immature state to spread out their picking periods. The immature red fru i t (No. 3 color comparator) (12, 13) i s more susceptible to surface disorders than f r u i t harvested at No. 6 color maturity (red-mahogany) or greater (18). Large crops also require increased production on automated packing lines which may increase the damage to the f r u i t . Cherry trees with heavy crops generally have small f r u i t (77). Cherries in a heavy crop year may attain the size of f r u i t in light crop years i f the f r u i t i s allowed to remain on the tree, but by this time may have passed optimum maturity resulting in the f r u i t texture becoming soft. Work by Proebsting (77) indicated that soft cherries are susceptible to surface disorders which may account for injury to f r u i t in heavy crop years. Low soluble solids in Montmorency cherries were inversely related to tree vigor and varied from year to year (40). Low f r u i t soluble solids were associated with heavy crops (77) and were positively correlated with high mechanical damage susceptibility (98). - 5 -The incidence of surface disorders in sweet cherries does not appear to be related to storage relative humidities of 80-95% (70). Desiccation of cherries in cold storage with humidity of approximately 80% RH resulted in loss of f r u i t turgidity and lack of skin luster (S.W. Porritt, Agriculture Canada, Summerland, B.C., unpublished results) but did not affect the incidence of surface disorders due to mechanical damage. Examination of weather records indicate that years of high f r u i t damage incidence have no correlation with water stress while the f r u i t i s on the tree. Simon (84) suggested, however, that disruption of cells within a fr u i t may promote localized drying which resulted in c e l l collapse and c e l l necrosis under storage conditions. Cherry fru i t i s often enclosed in 1.5 ml (38 ym) perforated polyethylene bags which maintain relative humidity at approximately 94% without affecting carbon dioxide or oxygen levels. Research by Porritt (70) determined that polyethylene liners were ineffective in reducing the incidence of surface pitting and may even have increased the disorder slightly. However, a research t r i a l in 1975 which examined 150 commercial packs of cherries determined that closed perforated polyethylene liners may have decreased the incidence of surface pitting slightly (S.W. Porritt, unpublished results). The evidence suggested that variations in storage relative humidity from 80 to 94% did not consistently modify surface pitting expression at 0°C. Research has indicated a strong cultivar-surface disorder relationship (70, M.E. Patterson, unpublished results). Bings and Lamberts were the least susceptible to surface disorders resulting from cellular damage whereas the Van cultivar was susceptible. - 6 -As the Van cherry accounts for approximately one third of the cherries grown in British Columbia with an approximate value of $1.3 million per crop year the threat of mechanical damage to the local f r u i t industry is substantial. The expression of surface pitting i s not affected by controlled atmosphere storage or high carbon dioxide levels in storage (36, 69). Carbon dioxide levels as high as 20% failed to affect pitting incidence significantly. Lowering oxygen levels from 21 to 3% and raising CO^  levels to as high as 13% also did not affect the incidence of surface defects. The development of surface pitting i s influenced by f r u i t temperature at the time of handling. Cherries are more susceptible to bruising and subsequent surface pitting when they were handled at 0°C than at 10°C or 24°C (M.E. Patterson, unpublished results). This effect of greater surface pitting susceptibility when frui t i s handled cold i s most important at the packinghouse level where the fruit is often precooled prior to packing. Fruit in the orchard at the time of picking w i l l not reach temperatures low enough to affect the incidence of surface pitting. Ogawa et^ a l . (61) however have shown that flesh discoloration due to bruising was unaffected by f r u i t temperature. Hydrocooling cherries has been shown to increase surface pitting (70). Patterson (unpublished data) however, has determined that hydrocooling subsequent to impact bruising did not modify the incidence of surface pitting. The increased incidence of surface pitting due to hydrocooling observed by Porritt et a l . (70) may be - 7 -the result of increased susceptibility of cold f r u i t to surface pitting from mechanical damage. Immature red cherries (No. 3 color comparator) are more susceptible to mechanical injury than are well matured mahogany (No. 6 to 33 cherry comparator) cherries (18, 72). The disadvantages of harvesting immature cherries are twofold: 1) increased susceptibility to pitting, and, 2) loss of fr u i t weight to the growers. Tukey (89) has observed sour cherries to gain approximately 3 to 4% of the total cherry weight per day in stage III of f r u i t development. Porritt e_t al. (70) observed great v a r i a b i l i t y of f r u i t susceptibility to surface disorders among trees. Similar observations of v a r i a b i l i t y of fr u i t susceptibility to surface disorders have to be made among grower lots. The range of bruise susceptibility suggests va r i a b i l i t y in grower practices. Preliminary investigations of s o i l pH (P. Lidster, unpublished results) indicate that acidic.soil conditions of pH below 4.5 are present in Okanagan cherry orchards. Low s o i l pH was found to decrease fru i t yield in Montmorency cherries but to have no effect on fr u i t size (1, 9). Reduced crop yields would, however, be expected to result in f r u i t less susceptible to surface disorders. However, acidic s o i l conditions can restrict the a v a i l a b i l i t y of nitrogen, calcium and zinc to the tree (88) while rendering manganese or aluminum available in toxic levels (31, 83). The restriction of nitrogen and calcium may lead to reduced tree vigor and fruit low in nitrogen and calcium. - 8 -Proebsting (Research Center, Prosser, Washington, unpublished data) has observed f r u i t deficient in nitrogen to be more susceptible to bruising damage. Nitrogen added to a sweet cherry orchard which was nitrogen deficient increased yield and fr u i t size (62) and increased fru i t nitrogen content (86). Applications of nitrogen or nitrogen plus phosphorus appeared to decrease the incidence of surface pitting (86). Stanberry and Clore (86) determined that s o i l nitrogen application of 270 lbs/acre imparted a resistance to surface pitting in cherries. In a preliminary sampling of Okanagan cherry orchards (P. Lidster, unpublished results), i t was determined that many cherry growers are applying the equivalent of 800 lbs/acre or greater of nitrogen f e r t i l i z e r s (34-0-0 or 21-0-0). Compared to current recommendations in Oregon of 200 to 300 lbs/acre of nitrogen f e r t i l i z e r (34-0-0), (T. Facteau, Experiment Station, Hood River, Oregon, unpublished results) the Okanagan applications are 4 times greater. Apparently cherry growers in the Okanagan try to increase f r u i t size through the application of nitrogen f e r t i l i z e r s alone. Added nitrogen increased the foliage surface area and subsequently increased the degree of fru i t shading (74, 104). Fruit grown in the shade was delayed in maturity and lower in alcohol insoluble solids (80). A high rate of nitrogen f e r t i l i z e r application can lower s o i l pH levels dramatically (32, 79). Once s o i l pH becomes acidic s o i l calcium becomes unavailable or leached (27) and calcium deficiencies may be induced by high aluminum or manganese concentrations (27, 83). High levels of ammonium ions also may decrease calcium uptake by plants - 9 -(30). However, increased amounts of calcium available to the plant roots was achieved by liming of acidic soils (34). Similarly, calcium levels of Montmorency cherry leaves were found to increase in seasons of high moisture (1). Calcium located within the frui t has a numb er of structural and physiological functions. Calcium may form bridges between adjacent c e l l wall pectins and serve to bind adjacent c e l l walls (30). Bangerth et a l . (5) suggested that as the frui t matures, the calcium joining the pectate chains is released and the individual cells become uncoupled. The separation of the cells i s associated with the decline of f r u i t flesh firmness. Increasing f r u i t calcium levels by the application of sprays or dips may maintain fru i t firmness by preventing calcium - pectate bridges from being uncoupled (29, 68). However, approximately one half of the calcium found in pear f r u i t i s not associated with binding of pectate chains (29). Calcium i s essential for the maintenance of the differential permeability and structural integrity of the cellular membranes (49, 51, 102). Cellular membranes are responsible for ion absorption and release selectivity of the c e l l (28, 50). The results of Van Stevenick (93) supported the hypothesis of Bennett and Rideal (9) in which the calcium adsorbed to the anionic moieties on the outside of the plasma membrane and not the structural calcium found within the membrane, was c r i t i c a l in maintaining selective permeability. The application of calcium to cellular structures can inhibit the progression of membrane leakage and can even reverse the process i f i t has not passed a c r i t i c a l stage (9, 90, 91). The decrease in the differential permeability of the - 10 -plasma membrane and tonoplast of f r u i t in a calcium deficient state w i l l result in the loss of cellular compartmentalization and lead to mixing of cytoplasmic enzymes and vacuolar substrates (81). Loss of cellular membrane integrity resulting from mechanical damage w i l l lead to increased respiration rates, accelerated ripening and an increase in the onset of damage disorders which may be reversed by the application of calcium (5, 78). Pruning of cherry trees may directly affect the fru i t susceptibility to mechanical damage. Pruning techniques may reduce crop loads which may indirectly provide cherries with a resistance to mechanical damage. Similarly, pruning may reduce the leaf surface area and allow f r u i t to receive more light. Ryugo and I n t r i e r i (80) determined that f r u i t grown in shade contained lower amounts of alcohol insoluble solids than f r u i t which was exposed. Similar observations were made on cherry leaves (1). Fruit low in c e l l wall components is li k e l y to be more susceptible to mechanical damage because weaker c e l l walls may be more prone to fracture under stress. Handling Practices Which Influence The Incidence of Surface Disorders Rough picking and handling procedures in the orchard w i l l predispose cherries to surface pitting and bruises in storage. S.W. Porritt (unpublished data) found a direct relationship between the roughness of handling and the incidence of surface pitting. Fruit - 11 -picked by clipping stems gently developed less surface pitting than f r u i t picked by grasping the stems in the usual manner and twisting to remove f r u i t . Observations of commercial fru i t lots (S.W. Porritt, unpublished data) showed that 31% and 53% total defects in Lambert and Van cultivars respectively were present in the f r u i t after dumping on the packing line. The total defects detected at this time were the accumulated defects from picking, transportation and dumping on to the packing line. Passage of the same frui t over the cluster cutter caused the total defects to increase to 61% for Lamberts and 89% for Vans. The injury imparted to cherries may result from either surface abrasion or impact damage (60, 85). Drupe fruits were susceptible to vibrational injury when warm (85) but were more resistant to impact injury. Injury from surface abrasion appears to affect epidermal cells only, whereas impact bruising results in collapsed hypodermal cells (2, 70). Injury occurring in f r u i t passed over commercial sorting belts results from both surface abrasion and impact damage (S.W. Porritt, personal communication). There is a great bruising potential inherent in automated cherry packing lines. Many existing lines have a total vertical drop of 3 to 4 feet over the packing line. Studies have shown (S.W. Porritt, unpublished data) that as l i t t l e as one foot of vertical drop is sufficient to cause significant amounts of surface pitting in years of susceptible f r u i t s . Consequently in such years, the vertical drop associated with commercial packing lines far exceeds that required to produce substantial damage. - 12 -Fruit can receive substantial damage during transit to market. O'Brien et a l . (60) found the extent of damage to be a function of f r u i t location within a carton and the acceleration given the f r u i t by vibration. Fruit which was loose on the top layers within a box received the most damage during transport which could involve 15% of the f r u i t . Current Canadian regulations permit a maximum of 15% total defects on arrival at the market inclusive of mechanical damage symptoms. Mechanical damage to cherries from a l l sources constitutes a serious threat to the pr o f i t a b i l i t y of commercial production of sweet cherries. Soft Cherry Fruit Problem Softness of sweet cherries has been ascribed to over-maturity, excessive r a i n f a l l or irrigation immediately prior to harvest, excessive f r u i t set and damage during picking and handling (59). Calcium deficiency was also reported to reduce f r u i t firmness and to result in lower insoluble pectic substances in Montmorency cherries (19). Softening of frui t was reported to be caused by solubilization of calcium ions from the galacturonic acid cross-linkages (4) which were responsible for the binding of c e l l walls by the middle lamella cementing structure (15, 33). Calcium was thought to interact with pectic compounds of cherries to increase fr u i t firmness (35, 58). Addition of calcium to Montmorency cherries increased firmness of the processed product after canning (7, 45). - 13 -The firmness of cherries may be important in determining acceptable eating quality and may be related to the susceptibility of cherry fruits to mechanical damage (E.L. Proebsting, M.E. Patterson, unpublished data). Hartman (37) and Hartman and Bullis (38) measured the force required to produce a constant deformation of cherries using a plunger. The resistance to deformation was found to decrease with advancing maturity. Hartman and Bullis (38) reported that the resistance to deformation of cherries harvested over the period from red to mahogany color decreased by 17.3 percent. The narrow firmness range for commercially mature cherries requires a sensitive firmness detection technique. Verner (94) used a similar method but compressed cherries between two f l a t plates and found this measurement unacceptable for predicting sweet cherry harvest dates. Couey and Wright (18) used a Durometer (Shore Instrument Co., Jamaica, N.Y.) to measure the surface resistance to compression in sweet cherries. Cherry texture as measured by the Durometer was directly related to the extent of impact bruising. However, this technique was subject to operator error as variations in the amount and rate of loading would greatly affect texture readings. Whittenberger and Marshall (99) studied the compression of individual sweet cherry fruits subjected to 300g force between fl a t plates. Parker et al. (64) and Diener et al_. (25) developed similar instruments to measure creep compliance of cherries under a constant load. Deformation of red tart cherries as an index of texture was related directly to the degree of bruising and other firming techniques. - 14 -LaBelle and Moyer (43) measured cherry texture as compliance under i t s own weight. The resistance to compression was found to increase in f r u i t that had been cold stored. Objectives of Present Study Previous research has indicated that the expression of surface damage symptoms can be modified by tree or storage treatments. The present study investigates the effects of various pre- and postharvest treatments on fr u i t texture and cherry susceptibility to mechanical damage. The research investigated the following areas: 1. The effect of f r u i t calcium supplements applied as preharvest sprays or postharvest dips on fruit texture and resistance to mechanical damage. 2. The effect of length of storage period prior to impact damage on the fruit susceptibility to mechanical damage. The effect of a delay prior to damage of fr u i t dipped in calcium chloride was also examined to determine whether the efficacy of a calcium dip could be improved. 3. The mechanism by which preharvest gibberellic acid sprays decrease f r u i t susceptibility to mechanical damage. 4. The effect of f r u i t maturity on cherry mineral and c e l l wall structure and the susceptibility to mechanical damage. 5. The moderating effect of temperature on the rate and total amount of surface damage resulting from impact bruising. - 15 -6. The elucidation of specific parameters of force and loading rate required to induce surface pitting and bruises. 7. The effects of storage temperature and widely differing storage relative humidities on f r u i t weight loss and the rate of development of surface damage. Dipping treatments which may modify f r u i t turgor, localized weight loss and the rate of surface disorder expression were also studied. 8. The effect of reducing crop load by hand thinning on f r u i t texture, contents and susceptibility to surface damage. - 16 -MATERIALS AND METHODS Firmness Determination The texture test consisted of forcing a 11 mm diameter Magness Taylor apple probe into the side of the fru i t (Fig. 4) using the Ottawa Texture Measuring System (96). The cherry was supported in an indentation of 3 cm radius in an aluminum plate to align the fru i t under the probe. The plate was arranged so that 3 fruits could be indexed under the probe in turn. The stem axis was at right angles to the direction of force application. The force transducer and strip chart recorder were adjusted to provide a f u l l scale sensitivity of either 2 or 4 kg. A crosshead speed of 1.5 cm/min was chosen to give good sensitivity with a reasonable testing rate. A typical force deformation curve is shown in Fig. 5. Fruit firmness was defined as the maximum slope (kg/cm) of the force-deformation curve. Fruit bioyield values were taken as the force at which there was a sudden decrease in the force sustained by the fruit due to tissue rupture. Deformation was the distance of probe travel from f i r s t contact with the cherry surface to the bioyield point. The fr u i t firmness, bioyield and deformation for each of 15 fruits tested were averaged to provide the textural attributes for a single replication. - 17 -Fruit Preparation and Mineral Analysis Frozen f r u i t samples for calcium analysis were removed after 5 to 10 days at -37°C and peeled to provide flesh tissue only. The remaining f r u i t flesh was allowed to thaw and then homogenized in a "Waring blendor" for 5 min. to provide a mascerate of the parenchyma tissue. About 5 grams of homogenized cherry tissue was weighed into a dry, tared 50 ml beaker. The tissue was freeze dried and the beaker reweighed to obtain tissue dry weight. The cherry tissues were then ashed at 550°C for 3 hours. The ashed samples were then taken up in 25 ml of 0.5N HCl with 6500 ppm lanthanum added and the resultant solution analyzed for calcium, zinc and potassium by atomic absorption. Analyses for magnesium required a further dilution of 2:25 with 0.5N HCl plus 6500 ppm lanthanum prior to atomic absorption analysis. Calcium-45 Determination Experiment 1. Van cherries of No. 6 color maturity and of uniform size were dipped in solutions of: 1) 30g/l calcium chloride, 2) 30g/l calcium chloride plus 0.1% non-ionic surfactant, 3) 30g/l calcium chloride plus 2.5g/l thickener (Keltrol)"'" or 4) 30g/l calcium chloride plus 2.5g/l thickener plus 1 ml/1 non-ionic surfactant. A l l solutions were labelled with 0.5 yCi calcium-45 per ml. The f r u i t was dipped by grasping 3 or 4 1 Keltrol is the brand name for food grade xanthan gum produced by Kelco Division of Merck and Co., Inc., San Diego, California. - 18 -separate fru i t at 21°C by the stem and immersing the f r u i t in 21°C dipping solution for 15 seconds. Fruit from each dip was divided randomly into 4 replications. A l l f r u i t was placed in corrugated paper-board boxes, surrounded by 38 p.m perforated polyethylene liners and placed immediately in 0°C storage. Fruit samples were removed after 1, 2, 4, 8 and 16 days of cold storage and washed with running water. Ten f r u i t were removed per replication, the stem removed and the fruit sliced in half along the suture line. The pit was removed and a No. 5 cork borer was pushed from the pit side through the flesh to the epidermis. The tissue plug was then removed from the cork borer by pushing the plug along the length of the borer to prevent tissue contamination. The tissue plug containing the epidermis was peeled prior to drying. Tissue plugs from identical treatments were collected from each of 10 cherries, placed in 50 ml tared beakers and dried to constant weight in a forced air oven at 65°C for two days (Fig. 6). Tissue dry weights were determined by reweighing the beakers. The tissue was then ashed at 550°C for 3 hours, and the ash taken up in 3 ml of 0.5N HCl. The solution was then poured into liquid s c i n t i l l a t i o n vials and an additional 2 15 ml of PCS liquid s c i n t i l l a t i o n cocktail added. The resulting mixture was analyzed by a Beckman LCS-100 liquid s c i n t i l l a t i o n counter. The quench correction curve (Fig. 7) was prepared using the channel ratios method. As the carbon-14 and calcium-45 energy spectrums overlapped (Fig. 8, 9), the entire calcium-45 energy spectrum was counted using a carbon-14 module. The i n i t i a l one-third of the calcium spectrum 2 PCS is brand name for liquid s c i n t i l l a t i o n cocktail produced by Amersham Searle Co., Arlington Heights, I l l i n o i s . - 19 -was counted by se t t i n g a v a r i a b l e counter to measure the counts per minute within the 0-260 range of s l i t widths. The channel r a t i o s and detection e f f i c i e n c i e s were determined on a set of 20 calcium-45 solutions of known a c t i v i t y but which were quenched progressively with acetone. A l l samples of cherry tissues were analyzed, corrected for background, quench and decay and values expressed as mg/kg calcium uptake from the postharvest dip. This technique was sim i l a r to that used by L i d s t e r e^ t auL. (47) . The data were analyzed by forward stepwise multiple regression using each and a l l combinations of the po t e n t i a l independent v a r i a b l e s ; Days, Log (Days), Surfactant, and Thickener. Experiement 2. The penetration of calcium-45 into the cherry mesocarp was examined. F r u i t s were dipped i n a solution of 30g/l C aC^ plus 2.5g/l thickener plus 1 ml/1 non-ionic surfactant and placed immediately i n 0°C storage i n 38 ym perforated polyethylene l i n e r s . Ten f r u i t per r e p l i c a t i o n were removed at 1, 2, 4, 8 and 16 days af t e r dipping and washed i n deionized water. The f r u i t was cut i n half along the suture l i n e and the p i t removed. A No. 5 cork borer was pushed through the half cherry from the p i t side. The tiss u e plug was then sectioned into three tissue discs of approximately 3 mm thickness each. Tissue discs from various depths were c o l l e c t e d from each of ten f r u i t and placed i n dried, tared 50 ml beakers. The epidermis was removed p r i o r to drying. Ashing and calcium-45 analysis was done using the procedure outlined i n Experiment 1. The data were analyzed by forward stepwise multiple regression using each and a l l combinations of the po t e n t i a l independent va r i a b l e s ; Days, Log (Days), and Depth. - 20 -Tissue Preparation for Microscopic Examination Tissue sections as approximately 2 mm cubes were removed at 0-2, 2-4 and 4-6 mm below the epidermis in areas receiving impact damage. The tissue was then fixed in a solution of 5% glutaraldehyde in 0.1M phosphate buffer for 5-12 hours. The fixed tissues were then rinsed twice with 0.1M phosphate buffer and replaced with a solution of 1% osmium tetroxide in Palade's buffer (63) for 1 hour. The osmium tetroxide solution was replaced by ascending steps of alcohol solutions repeated 3 times for duration of 20 min each. The f i n a l 100% alcohol solution was replaced with 2 changes of 100% propylene oxide 15 min each. The tissue was then immersed in a 1:1 propylene oxide-Epon 812 solution under 750 Torr vacuum for 12 hours. The sections were then embedded in 100% Epon-812 and cured for 36 hr at 60°C. The embedded tissues were o microtomed to 1500A thickness and stained with 1% basic fuschin in 50% ethanol (21). A l l tissue sections prepared were examined by light microscopy. Description of Damage Disorders The disorders of cherry fruits resulting from mechanical damage were categorized as to the overt symptoms: 1) fru i t with bruises which appeared as flattened surfaces on the cherry, 2) f r u i t with surface markings not deep or large enough to be considered pitting, 3) fruit with a small pit or pits with an aggregate pitting diameter less than - 21 -or equal to 5 mm, 4) f r u i t with large pits or aggregate pitting diameter greater than 5 mm, and 5) the number of pitted fruit per sample which included the summation of fru i t exhibiting pit symptoms. Tissue Fractionation and Analysis Alcohol insoluble solids. The fractionation and analyses of cherry tissue components was adapted from the procedures of Wiley and Stembridge (101) Blumenkrantz and Asboe-Hansen (10) and Sapozhnikova et. a_l. (82) . A composite sample of 150 g of fresh cherries was obtained from 50-75 individual f r u i t . The cherry slices were boiled in 95% ethanol for 5 min and the ethanol decanted. The cherry slices were then homogenized in 375 ml of 95% ethanol in a "Waring blendor" for 5 min. The homogenate was then filtered through a tared No. 541 f i l t e r paper and dried in a forced air oven at 65°C for 2 days. The weight of the dried residue was recorded as the AIS content on a fresh weight basis. Cellulose determination. A 0.5 g aliquot of dried AIS fraction was extracted with 30-35 ml of 10% KOH for 16 hours at 75°C to solubilize pectic substance and hemicelluloses. Antifoam-A was added during the extraction to prevent foaming. The remaining precipitate was filtered on a tared #1 f i l t e r paper and washed thoroughly with d i s t i l l e d water. The f i l t r a t e and f i l t e r paper were dried at 65°C for 2 days and the resulting weights recorded as percentage cellulose. - 22 -Soluble pectin determination. A 0.5 g aliquot of dried AIS fraction was brought to a boil in 50 ml of d i s t i l l e d water. The supernatant was collected and made up to 100 ml. To aliquots of 0.4 ml in an ice water bath, 4 ml of concentrated H^ SO^  - tetraborate were added and the mixture shaken. The resulting solution was heated to 100°C for 5 min and recooled in ice water for 10 minutes. Aliquots of 0.1 ml orthohydroxydiphenyl were added to samples and 0.1 ml of 0.5% NaOH to the blanks and contents stirred in a cold water bath. After a 10 min delay to allow color development the absorbance of the solutions was read at 477 nm. The absorbance readings were corrected for the blank values and concentrations of galacturonic acid interpolated from a standard curve. The results were expressed as percentage soluble pectin per fresh and dry weights. Total pectin determination. A 0.5 g aliquot of dried AIS sample was extracted with 30-35 ml of 0.25% ammonium oxalate and 0.25% oxalic acid at 75°C for 1.5 hr. The solution was filtered through nylon cloth and the f i l t r a t e extraction repeated twice. The supernatant from the three extractions was combined and the f i n a l volume determined. The pH of a 25 ml aliquot adjusted to 8.1 with 20% NaOH. To this solution, 2 ml of 10% HCl and 40 ml of 95% ethanol were added and the solution allowed to stand overnight. The resulting precipitate was centrifuged out at 15,000 rpm for 15 min and the supernatant decanted. The precipitate was redissolved in 10 ml of 0.2M Tris-HCl-EDTA (10). One ml of this solution was diluted 20 x with Tris-HCl-EDTA solution. Aliquots of 0.4 ml were analyzed for galacturonic acid as in soluble pectin determination. - 23 -Calcium Spray Experiments 1977 Study. A solution of 30 g CaCl- plus 1.0 ml/1 non-ionic surfactant was applied to whole branches selected at random on each of 5 trees of similar age and growth habit. Three sprays were applied at 2 week intervals commencing 6 weeks prior to harvest while the single CaCl2 spray was applied at 6 weeks prior to harvest. Fruits of uniform size were harvested at No. 6 color maturity. Texture tests and fru i t composition determinations were made on samples of 15 and 50 fr u i t respectively, immediately after harvest and after storage. Flesh calcium was determined after harvest. Impact injury to the frui t was imposed by placing f r u i t on a fiber conveyor belt arranged so that fru i t dropped 46 cm to another moving fiber belt. Belt speeds were such that fr u i t struck the surface of the belt and not other f r u i t . A l l fruit samples were bruised when the fr u i t temperature was 0°C. The data were analyzed as a 3 spray treatments x 5 replication factorial experiment using the Newman-Keuls multiple range test. 1978 Study. Branches picked at random in each of 4 tree (blocks) were sprayed with a solution of 30 g/1 CaC^ plus 1.0 ml/1 non-ionic surfactant. Sprays were applied so that one branch per tree received spray applications at: 1) 5 weeks prior to harvest, 2) 3 weeks prior to harvest, 3) 1 week prior to harvest, 4) 3 and 1 week prior to harvest and, 5) 5, 3, and 1 week prior to harvest. Fruit were harvested at No. 6 color maturity and - 24 -the texture tests done immediately on 15 f r u i t per sample at 21°C. The remaining f r u i t was impact damaged when f r u i t temperatures reached 0°C using the above method. A l l f r u i t were placed in 38 um perforated polyethylene l i n e r s to prevent desiccation and stored at 0°C. Fr u i t was removed for examination after 15 days of storage. The data were analyzed as a 5 treatment x 4 r e p l i c a t i o n f a c t o r i a l experiements using the Newmans-Keuls multiple range test. Calcium Dip Experiments Calcium penetration study. 'Van' cherries of uniform size and No. 6 color maturity were harvested and divided at random into 4 replications of approximately 1,000 f r u i t each. The f r u i t s were placed immediately in 0°C storage. A single sample of 50 untreated f r u i t was removed from each r e p l i c a t i o n and prepared for Ca analysis by being washed, destemmed, pitted and frozen at -37°C. The remaining f r u i t was dipped for 15 sec in a solution of 30 g/1 CaCl 2 plus 2.5 g/1 K e l t r o l thickener plus 1.0 ml/1 non-ionic surfactant plus 0.5 g/1 Benlate at 21 C. The f r u i t was allowed to drain and a second sample of 50 f r u i t s was prepared for Ca analysis. The remaining f r u i t s were placed i n corrugated paperboard boxes lined with perforated 38 ym polyethylene to prevent desiccation. F i f t y f r u i t s were removed at intervals of 1, 2, 4, 7, 14 and 21 days after dipping, 3 Benlate i s the brand name for benomyl fungicide produced by E.I. DuPont de Nemours & Co., Wilmington, Delaware. - 25 -and prepared for Ca analysis according to the above procedure. The data were analyzed by forward stepwise multiple regression using the p o t e n t i a l independent v a r i a b l e s ; Days, Log (Days), and Days x Log (Days). Thickener e f f e c t on CaCl„ dip. , T 7 , . . _• ._-2 Van cherries of uniform si z e were harvested at No. 6 color maturity and randomly divided into 12 treatments with 4 r e p l i c a t i o n s per treatment. F r u i t s were placed immediately i n 0°C. One hundred f r u i t s were dipped for 15 sec in solutions of 0, 15, 30 or 60 g/1 CaCl2 each at a thickener concentration of 0, 2.0, 4.0 g/1 thickener. A l l dipping solutions contained 1.0 ml/1 non-ionic surfactant and were maintained at 21°C. Dipped f r u i t was returned into polyethylene-l i n e d boxes and 0°C storage. The f r u i t was removed from storage after 21 days and 15 f r u i t s were warmed to 21°C for firmness determinations. The remaining 85 f r u i t s were washed, destemmed, p i t t e d and frozen at -37°C for Ca a n a l y s i s . The data were analyzed by forward stepwise multiple regression using each and a l l possible combinations of the 2 p o t e n t i a l independent v a r i a b l e s ; Dip ( C a C ^ ) , Dip (CaC^) , Thickener, 2 and Thickener . 1977 Dipping duration study. 'Van' cherries of uniform s i z e were harvested at No. 6 color maturity and randomly divided into 2 series of 5 treatments each with 4 r e p l i c a t i o n s of 100 f r u i t . The f i v e treatments i n the f i r s t s e r i e s consisted of a control and 4 others that were dipped for 0.25, 10, 60 or 240 min i n a so l u t i o n of 30 g/1 CaCl- plus - 26 -1.0 ml/1 non-ionic surfactant plus 0.5 g/1 Benlate. The second series was treated similarly to the f i r s t but with the addition of 2.5 g/1 Keltrol to the dipping solution. Warm frui t (21°C) was dipped after harvest in a 21°C solution. A l l fru i t were placed in boxes with perforated polyethylene liners and stored at 0°C for 21 days. Upon removal, 15 f r u i t were allowed to warm to 21°C and tested for firmness. The remaining 85 fr u i t were prepared and frozen for calcium analysis. The data were analyzed by forward stepwise multiple regression using each and a l l possible combinations of the potential independent variables; Dip Time, Log (Dip Time), and Thickener. 1978 Dipping duration study. 'Van' cherries were harvested from a single tree at No. 6 color maturity. The fruit was divided at random into 6 treatments of 4 replications of 50 fr u i t each. Warm frui t (21°C) was dipped in a solution containing 30 g/1 CaC^ plus 0.5 g/1 Benlate which was maintained at 21°C. The fr u i t was dipped for periods of 0.25, 1.0, 4.0, 16, 64 and 128 min. Immediately upon removal from the dipping solution, the fr u i t was rinsed under running water, allowed to dry, destemmed, pitted and frozen at -37°C for calcium analysis. The data were analyzed by forward stepwise multiple regression using the potential independent variables; Dip Time, Log (Dip Time), and Dip Time x Log (Dip Time). - 27 -Effects of pH of CaC_2 dipping solution on calcium uptake and disorder incidence. 'Van' cherries were harvested from each of 4 trees (replications) and randomly divided into 2 series of 5 treatments each. Each of 4 replications of 250 frui t was dipped in one of the 2 solution series containing 30 g/1 CaC^, plus 1.0 ml/1 non-ionic surfactant plus 0.5 g/1 Benlate with or without 2.5 g/1 thickener added. For each solution series the pH was adjusted to 1, 4, 7, 10 or 12 with either HCl or NaOH. Warm frui t (21°C) was dipped in the appropriate solution for 15 sec and the excessive dip solution allowed to drain from the f r u i t . The treated fru i t was then damaged by dropping the fr u i t 46 cm on to a fiber conveyor belt as described previously and then placed in paperboard boxes in a polyethylene liner and stored at 0°C. Fi f t y fruits which were dipped in the solution containing a thickener were removed from storage for each pH treatment, 1, 4, and 16 days after dipping. These fruits were washed, destemmed, pitted and frozen for calcium analysis. The remaining fruits were removed after 21 days of storage and examined for storage disorders. The data were analyzed by forward stepwise multiple regression using each and a l l combinations of the potential independent variables; pH, Days, 2 2 pH , and Days . Effects of washing on effectiveness of postharvest dips. 'Van' cherries were harvested at No. 6 color maturity and randomly divided into 4 replications for each of 5 dipping solutions and three washing regimes. - 28 -The 5 dipping solutions consisted of: 1) water, 2) 2.5 g/1 thickener, 3) 30 g/1 C a C l 2 , 4) 30 g/1 C a C l 2 plus 2.5 g/1 thickener and 5) 1:5 4 d i l u t i o n of Mobileaf a n t i t r a n s p i r a n t . A l l dipping solutions contained 1.0 ml/1 non-ionic surfactant plus 0.5 g/1 Benlate. The washing schedules consisted of: 1) no wash, 2) washing p r i o r to br u i s i n g , or 3) washing a f t e r b r u i s i n g of the f r u i t . F r u i t s were harvested and dipped immediately i n 21°C dipping sol u t i o n and placed i n 0°C storage u n t i l f r u i t temperature reached 0°C. F r u i t which required washing p r i o r to bru i s i n g were rinsed i n cold running water and returned to storage u n t i l the f r u i t reached 0°C. A l l f r u i t were then impact damaged by dropping the f r u i t 46 cm on a moving f i b e r b e l t i n g . F r u i t which required washing a f t e r bruising were rinsed i n cold water. A l l f r u i t were placed i n paperboard boxes i n polyethylene l i n e r s and replaced i n 0°C storage. F r u i t was removed a f t e r 14 days of storage and examined for surface disorders. The data were analyzed as a 5 dip x 3 wash x 4 r e p l i c a t i o n f a c t o r i a l experiment using the Newman-Keuls multiple range t e s t . E f f e c t s of soaking on surface disorders. 'Van' cherries were harvested at No. 6 color maturity with care to prevent damage to the f r u i t . The f r u i t was harvested from a s i n g l e tree and randomly divided to give samples for 2 dipping series x 5 dipping sequences x 4 r e p l i c a t i o n s of 150 cherries each. A l l f r u i t was cooled to 0°C within 12 hr of harvest. 4 Mobileaf i s the brand name for wax emulsion antitranspirant produced by Mobil Chemical Co., Richmond, Va. - 29 -One ser i e s of f r u i t was dipped i n a 21°C solution containing 0.5 g/1 Benlate plus 1.0 ml/1 non-ionic surfactant for periods 15 sec, 4, 16, 64, and 128 min a f t e r which the f r u i t was cooled to 0°C. A l l f r u i t was impact damaged by a free f a l l of 46 cm on to a moving f i b e r b e l t . The second series of f r u i t was then dipped i n the i d e n t i c a l s o l u t i o n for periods of 15 sec, 4, 16, 64 and 128 min. After treatment a l l f r u i t were replaced i n perforated polyethylene l i n e r s and placed i n 0°C cold storage for 14 days. F r u i t were removed from storage and examined for surface disorder incidence. The data were analyzed by forward stepwise multiple regression using each and a l l combinations of the p o t e n t i a l independent v a r i a b l e s ; Dip Sequence, 2 Dip Duration, and Dip Duration . Delay Versus Calcium Dip Experiments 1977 Study. 'Van' cherries were harvested c a r e f u l l y at No. 6 color maturity. Eight samples of 150 f r u i t each were selected from each of f i v e tree-blocks. The f r u i t was cooled overnight to 0°C. Samples were then dipped i n either a s o l u t i o n of 30 g/1 CaC^, plus 2.5 g/1 thickener, plus 1.0 ml/1 non-ionic surfactant, plus 0.5 g/1 Benlate fungicide or a s o l u t i o n of 1.0 ml/1 non-ionic surfactant plus 0.5 g/1 Benlate and allowed to dry i n cold storage for 4 hr. A l l f r u i t samples were then placed i n 38 ym perforated polyethylene l i n e d corrugated paperboard boxes to prevent desiccation. Samples were impact damaged by dropping the f r u i t 46 cm on a f i b e r conveyor be l t 0.5, 4, 8 or 12 days - 30 -after the dip treatment and then returned to 0°C storage in polyethylene liners. The data were analyzed by forward stepwise multiple regression using each and a l l combinations of the potential independent variables; Dip CaC^? Days Delay, and Log (Days Delay). 1978 Study. 'Van' cherries were harvested carefully at No. 6 color maturity from a single tree. The fruit was randomly divided into 4 replications of 16 samples to provide for 4 postharvest dips and 4 delay periods prior to bruising. The following dipping treatments were applied immediately after harvest: 1) water, 2) 30 g/1 CaC^, 3) 2.5 g/1 thickener, or 4) 30 g/1 CaC^ plus 2.5 g/1 thickener. A l l dipping solutions contained 1.0 ml/1 non-ionic surfactant plus 0.5 g/1 Benlate fungicide. The f r u i t samples were placed in 38 ym perforated polyethylene lined corrugated boxes and cooled to 0°C before folding the liner over the f r u i t to prevent desiccation. Samples were removed from storage and impact bruised at 1, 2, 4 or 8 days after harvest. The fru i t was damaged by dropping 46 cm on to a moving fiber belt after which the frui t was returned to 0°C storage in polyethylene liners. Fruit was removed from storage 15 days from date of impacting and immediately examined for disorders. The data were analyzed by forward stepwise multiple regression using each and a l l combinations of the potential independent variables; Dip CaC^; Dip Thickener, Days Delay, and Log (Days Delay) . - 31 -Gibberellic Acid Experiments 1977 Study. Two individual branches selected at random within each of 5 tree-blocks were sprayed by handgun with solutions of: 1) 20 ppm gibberellic acid (GA) and 2) 1:5 dilution of Mobileaf antitranspirant. Sprays were applied at green-straw fru i t maturity approximately one month prior to harvest. One branch of the remaining unsprayed portion of each tree was selected as a control. Fruit was harvested at two maturities corresponding to No. 3 and 33 fr u i t color. Approximately 150 fruits were harvested per replication with care to prevent damage. A l l f r u i t was stored immediately at 0°C. The fr u i t was impacted by dropping 46 cm on a fiber belt and replaced in polyethylene liners in 0°C storage. Fruit was examined for disorders after 21 days of cold storage. The data were analyzed as a 3 treatment x 2 maturity x 5 replication factorial experiment using the Newman-Keuls multiple range test. 1978 Study. Thirty parts per million gibberellic acid (GA) sprays were applied to branches selected at random in each of 4 tree-blocks. The spray was applied at straw color f r u i t maturity approximately 21 days prior to harvest. Control branches were selected at random from the remaining unsprayed portion of the tree. Approximately 250 fruit were harvested at each of two maturities corresponding to No. 3 and 33 fruit color. Immediately after harvest, 100 fruits were destemmed and fruit weight determined. Pits were removed from 50 of these fruits and 150 g of cherry slices prepared for determination of alcohol insoluble solids, - 32 -pectin and cellulose. The other 50 fruits were pitted and frozen for mineral analysis. The remaining 150 fruits per replication were cooled at 0°C then impact damaged as described previously and stored at 0°C in polyethylene liners. Fruit was examined after 21 days of cold storage. The data were analyzed as a 2 treatment x 2 maturity x 4 replication factorial experiment using forward stepwise multiple regression. The dependent variables were predicted using the potential independent variables; Maturity, Gibberellic Aid Spray, and Maturity x Gibberellic Acid Spray. Fruit Maturity Experiments 1977 Study. 'Van' cherries were harvested at 3 maturities corresponding to No. 3, 6 and 33 f r u i t color. Fifteen fruits from each of 4 replications per maturity were selected for soluble solids, titratable acidity and mineral analysis determinations before and after 21 days of storage. Soluble solids were determined by refractive index of the juice sample. Titratable acidity measurements were determined by titrating 10 ml of juice with 0.1 N NaOH to pH 8.1 as the endpoint. Four samples of 150 fru i t each were harvested at each of the three maturities. Fruit was picked carefully to avoid damage and randomly divided to give 4 replications for each of the 4 treatments. The fr u i t was cooled immediately to 0°C and impact damaged by dropping fru i t of known weight sufficient distance to provide work equivalent to 0.0, 0.02, 0.04 and 0.08 joules (Fig. 9). The damaged fr u i t was placed in polyethylene - 33 -liners and replaced in 0 C storage for 21 days then examined for disorder incidence, soluble solids, titratable acidity and fruit texture. The data were analyzed as a 3 maturity x 4 work load x 4 replication factorial experiment by forward stepwise multiple regression using each and a l l combinations of the potential independent 2 variables; Maturity, Work Done, and Work Done . The data analyses not involving variable amounts of work done to the fr u i t were accomplished using Newman-Keuls' multiple range test. 1978 Study. 'Van' cherries were harvested every 7 days commencing when f r u i t maturity corresponded to straw-green color. This maturity approximated the i n i t i a t i o n of stage III of fr u i t development observed by Tukey (89). Approximately 250 fr u i t were harvested at each harvest. One hundred f r u i t were used prior to storage for texture, soluble solids, titratable acidity, mineral and alcohol insoluble solid determinations. Total f r u i t nitrogen content was determined on dry fru i t tissue using a standard micro-Kjeldahl procedure. The remaining fruits were cooled rapidly to 0°C then bruised by dropping the frui t on a fiber belt from a height which corresponded to 0.04 joules of work (Fig. 9). The f r u i t was returned to 0°C storage in polyethylene liners for 15 days then examined for disorders. The data were analyzed by forward stepwise multiple regression using the potential independent variables; 2 Days, and Days . - 34 -Effects of Fruit Size on Composition and Disorder Incidence Maturity versus f r u i t size. 'Van' cherries were harvested at No. 3, 6, and 33 fr u i t color maturities from 5 tree-blocks. Fruit from each tree for each maturity was segregated into 2 sizes, small and large. A l l f r u i t was cooled to 0°C overnight and dropped 46 cm on to a fiber belt then returned to 0°C storage in polyethylene liners for 21 days. The f r u i t was then assessed for damage. The data were analyzed as a 3 maturity x 2 size x 5 replication factorial experiment using Newman-Keuls' multiple range test. Drop height versus f r u i t size, 1977 study. 'Van' cherries were harvested at No. 6 color maturity from 5 tree-blocks. The frui t was segregated into 2 series of small and large sizes cooled to 0°C then one series was dropped 46 cm on to a moving fiber belt and the second series was dropped a height equivalent to 0.05 joules of work as determined by fruit weight. A l l f r u i t was stored in polyethylene liners at 0°C and assessed for the incidence of damage after 21 days. The data were analyzed as a 2 fruit weight x 2 treatment x 5 replication factorial design by forward stepwise multiple regression using the potential independent variables; Fruit Weight, Work Done, and Fruit Weight x Work Done. Drop height versus f r u i t size, 1978 study. 'Van' cherries were harvested at No. 6 color maturity from 4 tree-blocks. Fruit from each tree was segregated into small and large f r u i t size categories and 100 fruits in each group were weighed to determined average f r u i t weight. These - 35 -fruits were then pitted and sliced to provide 150 g fr u i t tissue for alcohol insoluble solid determinations and the remainder used for soluble solids and titratable acidity determination. Two series of small and large f r u i t each were subdivided from the remaining fru i t from the 4 tree-blocks and cooled to 0°C. One series each of small and large f r u i t was dropped on to a fiber belt at a constant height of 0.45 meters. The remaining series of f r u i t were dropped a height equivalent to 0.04 joules of work. The frui t was returned to 0°C storage in polyethylene liners and after 15 days, 150 fruits in each replication were examined for disorders. The data were analyzed as a 2 x 2 x 5 replication factorial experiment by forward stepwise multiple regression using the potential independent variables; Fruit Weight, Work Done, and Fruit Weight x Work Done. Effects of Bruising Surface and Rate of Deformation Height of drop versus bruising surface. 'Van' cherries were carefully harvested at No. 6 color maturity from 5 tree-blocks. The fru i t from each tree was randomized into 2 series of 4 treatments each. A l l fru i t were cooled to 0°C. Each series of fr u i t was dropped distances of 13, 25, 51 and 102 cm on either a woven fiber belt or smooth plastic belting material. Care was taken to avoid fru i t collisions at the belting surface. A l l fruits were stored at 0°C in polyethylene liners and examined for surface disorders after 16 days. The data were analyzed by forward stepwise multiple regression using each and a l l combinations of the potential independent variables; Surface, Drop Height, 2 and Drop Height . - 36 -Deformation rate versus bruising surface. 'Van' cherries of No. 6 color maturity were harvested carefully from a single tree and randomly divided into treatments of 2 bruising surfaces x 2 loading rates x 3 depths of deformation. The cherries were deformed to 2, 4 or 8 mm using either a smooth plastic or woven fiber belting material at loading rates of either 10 or 1000 mm/min. Each treatment consisted of 4 replications of 35 cherries each. Fruit was cooled to 0°C prior to bruising. Fruit was bruised using an Instron Universal testing machine by placing individual f r u i t s , with the suture parallel to the fl a t surface, and allowing the f l a t surface to deform the cherry, with appropriate belting material on the opposite side of the f r u i t . Fruit was replaced in polyethylene liners in 0°C storage for 10 days and examined for surface disorders. The data were analyzed by forward stepwise multiple regression using each and a l l combinations of the potential independent variables; Bruising Surface, Deformation, 2 Deformation , and Loading Rate. Fruit and Storage Temperature Effects on Damage Incidence Fruit temperature study, 1977. 'Van' cherries were gently harvested at No. 6 color maturity from several trees and the fr u i t divided at random into 5 treatments x 4 replications of 150 f r u i t each. Fruit was brought to temperatures of 0, 5, 10, 25 and 38°C then damaged by dropping a distance of 46 cm on to a moving fiber belt. A l l fruit was then placed in polyethylene liners in 0°C storage. After 21 days the - 37 -f r u i t was removed from storage and examined for surface disorders. The data were analyzed by forward stepwise multiple regression using the potential independent variables; Fruit Temperature, and Fruit 2 Temperature . Storage temperature study, 1977. The 'Van' cherries were harvested carefully at No. 6 color maturity from several trees and the f r u i t divided at random into 3 treatments x 4 replications of 150 fru i t each. Fruit was cooled to 0°C prior to bruising. Subsequent to impact damage, two lots of f r u i t were placed in 0°C storage while the remaining fru i t was placed in 25°C storage. Fruit from 0 and 25°C storage was removed after 5 days and examined for surface disorders. The remaining 0°C treatment was removed from storage after 15 days and examined for surface disorders. The data were analyzed using the Newman-Keuls multiple range test. Fruit temperature study, 1978. 'Van' cherries were harvested carefully at No. 6 color maturity from a single tree and randomly divided into 4 periods in storage x 4 bruise temperatures x 4 replications of 150 cherries each. Fruit temperatures of 0, 5, 10 and 20°C were achieved within 12 hours of harvest at which time fru i t was impact damaged by dropping 46 cm on to a moving fiber belt then stored in polyethylene liners at 0°C. After 1, 2, 4 and 8 days storage the f r u i t was examined for surface disorders. The data were analyzed by forward stepwise multiple regression using each and a l l combinations of the potential independent variables; Days, Log (Days), and Temperature. - 38 -Storage temperature study, 1978. 'Van' cherries were harvested carefully at No. 6 color maturity from a single tree and randomly divided into 5 periods in storage x 4 storage temperatures x 4 replications of 150 cherries each. Fruit cooled to 0°C was impact damaged by a distance of 46 cm free f a l l on to a moving fiber belt. Five samples of 4 replications each were stored in polyethylene liners at 0, 5, 10 and 20°C. Fruit was removed at intervals of 1, 2, 4, 8 and 16 days after bruising and examined for surface disorders. The data were analyzed by forward stepwise multiple regression using each and a l l combinations of the potential independent variables; Days, Log (Days), and Temperature. Effects of Storage Temperature and Humidity on the Incidence of Surface Disorders 'Van' cherries of No. 6 color maturity were harvested from several trees and the f r u i t randomly divided into 2 storage temperatures x 5 removal dates x 2 storage relative humidities x 4 replications of 150 cherries each. Fruit were enclosed in polyethylene and cooled to 0°C within 12 hours of harvest and impact damaged by dropping 46 cm free f a l l on to a moving fiber belt. Five samples of 4 replications each were placed in storage at: 1) 0°C 95-100% RH, 2) 0°C 40% RH, 3) 20°C 95-100% RH, and 4) 20°C 40% RH. The f r u i t was examined for weight lost and surface disorders after periods of 1, 2, 4, 8 and 16 days. The data were analyzed by forward stepwise multiple regression using - 39 -each and a l l combinations of the potential independent variables; Humidity, Days, Log (Days), and Temperature. Effects of Thinning on Fruit Characteristics and Resistance to Impact Damage Five 'Van' cherry tree blocks in each of two commercial orchards were selected on the basis of heavy f r u i t set. Three weeks after f u l l bloom, the cherries on a branch selected at random from each tree were thinned by hand to one f r u i t per cluster. The fru i t was harvested at No. 6 color maturity and 100 fruits were weighed to determine average f r u i t weight. Samples of 15 and 50 fru i t were used for prestorage determinations of texture and f r u i t analysis respectively. A further set of f r u i t samples of 15 and 50 f r u i t per replication were stored in polyethylene at 0°C for 21 days for texture, soluble solids and titratable acidity determinations. A sample of 150 f r u i t per replication cooled to 0°C were impact bruised by free f a l l of 46 cm on to a moving fiber belt. The fru i t was replaced in polyethylene liners and stored at 0°C for 21 days after which f r u i t was examined for surface disorders. The data were analyzed as a 2 treatment x 2 location x 4 replication factorial experiment by forward stepwise multiple regression using the potential independent variables; Thinning, Orchard, and Thinning x Orchard. - 40 -Microscopic Examinations 'Van' cherries were harvested at No. 3 and 6 color maturities and cooled to 0°C immediately after harvest. Twenty fruits of each maturity were bruised by dropping a 16 g centrifuge tube with a rounded bottom a distance of 30 cm on to the cheek of the f r u i t . The impact area was circled for later identification. The fr u i t was placed in polyethylene liners in 0°C storage. Twenty undamaged frui t served as controls. Ten control f r u i t and 10 damaged f r u i t were sectioned immediately. The remaining 10 control and 10 damaged frui t were sectioned after 9 days of storage. - 41 -RESULTS AND DISCUSSION Calcium Study Rate of calcium penetration. Calcium penetrated into the fr u i t rapidly (Fig. 11) and approached an asymptotic maximum level 7 days after a post harvest CaCl^ dip. The cherry cuticle and epidermis were very permeable (Fig. 11) to calcium movement allowing a 100 ppm increase from an undipped control level of 545 ppm in mesocarp calcium concentration even when f r u i t were washed immediately after dipping. Calcium moved rapidly into cherry fru i t mesocarp during prolonged dipping periods (Table 3). Flesh calcium levels increased to 266 ppm when f r u i t was exposed to the dipping solution for 128 min. These observations were consistent with those which show that water could move rapidly into cherry f r u i t to cause cracking (95). The rate of calcium uptake by the cherry f r u i t declined after the f i r s t day until after 7 days in storage when only small increases in calcium uptake were evident. The high calcium concentration in f r u i t tissues at 7 days or later corresponded to the high efficiency of CaCl. dips to reduce surface disorders (Tables 4, 5). Apparently, the calcium concentration in the f r u i t flesh equilibrated with the residual calcium within 7 days of dipping. Radiotracer studies showed that calcium from a postharvest dip moved readily into cherry f r u i t flesh (Fig. 12). Significant amounts of calcium-45 were detected in the 6-9 mm depth of flesh 2 days after the dip. Calcium uptake at a l l flesh depths increased progressively with - 42 -increased time in storage. The results in Fig. 12 indicate that the calcium penetration into cherry flesh approaches an upper asymptotic level approximately 8-16 days after dipping. The decreased rate of calcium uptake with storage time agrees with the previous results as determined by atomic absorption (Fig. 11). The results using calcium-45 however, indicate that the flesh calcium levels continue to increase after 8 days but at a reduced rate. Factors affecting calcium uptake. Flesh calcium concentration determined by atomic absorption was increased by raising calcium chloride concentration in the postharvest dipping solution (Fig. 13). Addition of a thickener to the calcium chloride dip further increased calcium uptake by the f r u i t . A dipping solution containing 8% calcium chloride and 0.4% Keltrol resulted in a 4-fold increase in frui t calcium levels from 450 ppm in the control to 2260 ppm. The addition of thickener to the calcium chloride dipping solution was previously found to enhance calcium uptake in apples (48, 54). Mason et jil_. (54) concluded that a thickener added to the dipping solution caused more dip to adhere to the surface of the f r u i t which resulted in greater calcium uptake by the f r u i t . Calcium uptake, as determined by radiotracer techniques, was also greatly modified by the inclusion of surfactants and thickeners in the dipping solution (Fig. 14). Addition of a non-ionic surfactant to the calcium chloride dipping solution decreased calcium uptake from that obtained from a solution not containing a surfactant. These results agree with the data of Mason e_t a l . (54) on apples. The - 43 -addition of 0.25% thickener to the calcium chloride dipping solution greatly increased calcium uptake by the cherry flesh. The addition of a surfactant to the dipping solution containing a thickener i n i t i a l l y reduced calcium penetration into the cherry flesh, but after 5 days, calcium absorption in fr u i t dipped in a solution of thickener and surfactant exceeded the calcium uptake of that without surfactant. These results are in contrast to those of De V i l l i e r s and Hanekom (24) which showed that i n i t i a l uptake of calcium by Golden Delicious apples was enhanced by the inclusion of a surfactant in a calcium chloride plus thickener solution, but ultimately more calcium was absorbed by fruit when the surfactant was omitted. The differences in the rates of calcium uptake may be due to the innate differences between fruits of cherries and apples. Cherries appear to be much more permeable to calcium penetration than apples (53, 54). This may be because cherries have a larger surface/volume ratio than apples. Large droplets which remain on the cherry surface when dipped may influence a greater portion of the cherry than i s the case for a much larger apple f r u i t . Dipping cherry f r u i t s for 0.25 min increased fru i t calcium content by 170 and 440 ppm for calcium chloride solutions without and with 2.5 g/1 thickener, respectively. The mesocarp calcium levels were increased by prolonging the contact time with the dipping solution as determined immediately after the dip (Table 3) and after 21 days of 0°C storage (Fig. 15). Adjusting the pH of the CaC^ dipping solution to 7.0 resulted in maximum calcium uptake (Table 6). Basic or acidic dipping solutions greatly decreased the efficacy of calcium chloride dips. Normal pH of a 4% CaCl 9 solution with thickener is usually near - 44 -pH 10. Therefore increased calcium penetration may be achieved by lowering the dipping solution pH with hydrochloric acid to pH 7. Basic CaC^ dipping solutions may form insoluble carbonates and result in ionic calcium being unavailable for frui t penetration. On the other hand, acidic solutions have been shown to extract calcium from frui t tissues (67). Highly acidic CaC^ solutions may dislocate fruit calcium bound to exchange sites (8, 73) and make fr u i t calcium more mobile. A reduced amount of bound calcium on fr u i t surfaces when removed from the dip may result in decreased calcium influx into the f r u i t . A single preharvest CaC^ spray six weeks prior to harvest did not raise flesh calcium levels significantly. However, 3 preharvest CaC^ sprays were effective in raising cherry flesh calcium levels by 100 ppm (Table 7). Mason (52) observed preharvest CaC^ sprays increased f r u i t calcium levels in Spartan apples. No significant effect on fruit Mg, K or Zn levels were observed as a result of CaC^ sprays. Effects of CaC^ spray and postharvest dips on fru i t texture. Fruit firmness and bioyield showed similar positive correlations with flesh calcium concentration following a calcium chloride dip (Fig. 16, 17). Fruit deformation to bioyield, however, was not significantly correlated (p > 0.05) with flesh calcium concentration. Higher calcium levels resulted in increased flesh firmness and bioyield determined after 21 days storage. Increased flesh calcium levels caused by raising CaCl 0 or thickener concentration in the dipping solution resulted in - 45 -proportionately higher f r u i t firmness and bioyield readings. This phenomenon of increasing firmness is different from the calcium effect in retarding the loss of firmness in stored apples (53). The data in Figs. 16 and 17 indicate that mesocarp calcium levels were increased, and corresponding increases in f r u i t firmness and bioyield occurred, as a result of prolonging the contact time of the f r u i t with the dipping solution. The actual fru i t firmness and bioyield values (Tables 8, 9) show a general relationship to the values predicted from the mesocarp calcium levels in Figs. 16 and 17. However, fr u i t firmness appeared to be greater than the values predicted from calcium levels for the 4 hr dip (Tables 8, 9). This suggests that prolonged soaking may increase f r u i t firmness irrespective of the effect of calcium. The firming effect of prolonged soaking has been previously documented (7, 14, 44). The infusion of calcium into mesocarp tissues may have increased bioyield and f r u i t firmness by preventing the disruption of calcium bonds and by the formation of additional calcium cross-linkages between polygalacturonic acid chains (4) which are largely responsible for the cementing features of the middle lamella (33). McCready and McComb (58) suggested that calcium could form a calcium pectate gel within cherries. A greater resistance to c e l l rupture and shearing between adjacent cells would result from a calcium f o r t i f i e d middle lamella thereby providing increased bioyield and firmness values. A single CaC^ spray 6 weeks prior to harvest had no effect on f r u i t calcium content or textural attributes (p > 0.05) (Tables 7, 10), but cherry fr u i t s which received 3 CaCl 9 sprays had higher mesocarp - 46 -calcium levels and were firmer than the unsprayed controls at harvest. These results agree with those of Bedford and Robertson (7) which show that CaC^ applications result in firmer canned Montmorency cherries. However, the firming effect of CaCl^ sprays was not apparent after 21 days of storage. Effects of CaC^ application and delay in storage on damage disorder incidence. The incidence of bruised fru i t was negatively correlated with the length of storage period prior to impact damage (Tables 4, 5). A 12-day delay decreased the incidence of bruised f r u i t by approximately 50% in 1977 and an 8-day delay decreased the incidence of bruised fruit by approximately 66% in 1978. Postharvest CaC^ dips had no effect on the incidence of bruising at any delay period. The preharvest CaC^ sprays decreased the incidence of f r u i t pitting and increased the incidence of bruises (Tables 11, 12). Pitting appears to result from c e l l rupture and tissue collapse (Figs. 18, 19, 20), while bruises are considered to be in expression of mechanical damage which causes distortion of the f r u i t parenchyma cells without c e l l rupture (Figs. 22, 23). Cold storage prior to impact damage apparently increases the resistance of the f r u i t to cellular distortion caused by impact. The infusion of calcium into the f r u i t flesh may strengthen c e l l walls and thus prevent c e l l rupture due to mechanical damage. The term surface marking is used in these studies to describe small miscellaneous indentations in the skin and outer c e l l layers adjacent to the epidermis. In this area, the cells have been damaged - 47 -by localized pressure such as that imposed by cherry stems, particularly stem ends. Storage periods of up to 12 days prior to bruising did not affect the amount of surface marking but a postharvest CaCl2 dip was effective in reducing the incidence of surface markings in both years studied. Preharvest CaC^ sprays however had no significant effect on the incidence of surface markings (Tables 9, 10). Increased tissue calcium from the postharvest dip may strengthen c e l l structure sufficiently to reduce surface markings even in fr u i t damaged 12 hours after dipping. The incidence of pitting declined with increasing time in 0°C storage prior to impact damaging the f r u i t . Fruit dipped in CaCl_ plus Keltrol solutions showed reductions in the incidence of small, large and total pitting for a l l storage periods. The calcium content of cherry tissue increases rapidly following a dip in CaC^- Calcium concentrations in 'Van' cherries increased by several hundred ppm within 2 days of dipping (Figs. 11, 12). The CaCl^ was highly effective in preventing the occurrence of large pits and in reducing the total number of pits in cherries damaged immediately after dipping or in those which were damaged after various periods of cold storage. In the 1978 study, however, dipping fruit in CaCl2 without thickener had no effect on the incidence of pitting. This suggests that high f r u i t calcium levels resulting from calcium dips with thickener (Fig. 13) are required to impart fru i t resistance to mechanical damage. Increased f r u i t calcium levels resulting from preharvest CaCl 9 sprays were negatively correlated with the incidence - 48 -of large and total surface pitting. Calcium may react with free carboxyl groups of polygalacturonic acid molecules to increase the strength of intercellular bonds (4, 15, 34, 41, 86) thus increasing the resistance of the tissue to damage. Increasing the calcium content of 'Van' cherries by postharvest CaC^ dips was shown to increase f r u i t firmness and resistance to c e l l rupture as measured by bioyield (Fig. 16, 17). The reason a delay in storage reduced surface disorders due to mechanical damage is not clear. Couey and Wright (18) found that cold f r u i t was more susceptible to bruises than warm f r u i t . Porritt et a l . (70) reported that hydrocooled f r u i t was even more susceptible to pitting than aircooled f r u i t at 0°C. The immediate effect of cooling may be to reduce tissue resilience so that i t is more susceptible to mechanical damage. Whittenberger (100) suggested that postharvest aging of Montmorency cherries may strengthen intercellular cement which may impart a resistance to c e l l rupture when the f r u i t is damaged. Gee and McCready (35) observed a similar toughening of frozen Montmorency cherries and suggested that the texture changes were the result of enzymic de-esterification and the formation of a calcium pectinate gel. During extended cold storage, however, i t appears that changes occur which are not attributable to water loss from the f r u i t but which result in increased resistance to impact damage. - 49 -Factors affecting the efficacy of postharvest dips in preventing  surface damage of f r u i t . The pH of CaCl^ dipping solutions was shown to modify greatly calcium penetration into the cherry flesh (Table 6), and to have a significant effect on the incidence of surface disorders due to mechanical damage (Table 13). The incidences of bruises, surface markings and small surface pitting showed positive correlation with the pH of the dipping solution. However, the incidence of f r u i t with large and total surface pitting was a minimum when dipped in a CaC^ solution with a pH 4. The optimum efficacy of a CaCl_ dip in preventing surface disorders corresponds very closely to the pH optimum for maximum calcium uptake. The positive correlation of surface markings, bruises and small surface pitting with dipping solution pH is as yet unexplained. Commercial handling of the fresh cherry crop requires that f r u i t be picked, packed and shipped to market within 3 days in most instances. Therefore, the time allowed for calcium to penetrate the fr u i t flesh from a postharvest CaC^ dip prior to washing and packing may be as l i t t l e as several hours. The incidence of surface damage in fr u i t dipped in water prior to impact damage was not significantly different from non-dipped f r u i t (Table 14). This suggests that water on the surface of the f r u i t is ineffective in lubricating the fr u i t to lessen the degree of damage. Similarly the lubricating effects of a thickener solution on the fr u i t surface to lessen the magnitude of damage were insignificant. However, the thickener solution when allowed to remain on the f r u i t surface after damage decreased the incidence of - 50 -large and total pits. This effect may be due to restriction of water loss due to the thickener coating preventing formation of sunken pits. Calcium chloride applied without thickener and not washed off prior to storage and CaC^ applied with thickener significantly decreased the incidence of f r u i t bruises and surface pitting. However, dipping fru i t in CaC^ with thickener was most effective in reducing surface damage when the fr u i t remained unwashed. Washing the dipping solution from the surface of the f r u i t might be expected to decrease the surface supply of calcium for penetration and hence reduce the efficiency of a CaC^ dip. Substantial reductions in the incidence of bruises and surface pitting however, resulted from CaC^ plus thickener dips even when washed immediately after dipping. This suggests that dipping fru i t may have commercial application in reducing surface disorders. The frui t may be dumped into a CaC^ plus thickener solution prior to the cluster cutter in a commercial packing line. The CaC^ plus thickener dip may then be washed off the f r u i t by water jets prior to sorting. This procedure could result in 30% reductions in the incidence of surface pitting. Effects of Storage Humidity and Water Loss on Surface Disorder Expression Low storage humidity of 40% RH increased water loss (Fig.24) and the rate of formation of large pits (Table 14). Storage temperatures interacted with storage humidity to modify the rate of surface pitting - 51 -formation. A temperature of 20°C and low storage humidity of 40% RH resulted in most rapid rate development of surface pitting. Fruit stored at 0°C storage, however, developed a slightly higher incidence of pitted f r u i t than at 20°C storage after 16 days. Porritt et a l . (70) suggested that surface pitting development was independent of weight loss. The present results indicate, however, that the rate of surface pitting development can be enhanced by storage conditions that promote weight loss. Other evidence in this study (Table 15) indicated that dipping f r u i t in an antitranspirant film to restri c t water loss (20) significantly reduced the expression of surface pitting. Histological examination (Fig. 20) indicate that c e l l rupture results immediately upon impact damage. Fracture of c e l l membranes and walls w i l l lead to mixing of vacuolar and cytoplasmic contents and weakening of the 3-dimensional cellular matrix. Surface pitting does not occur immediately after impact damage because the contents of the ruptured cells are s t i l l present. Water loss may be necessary for the disorder to appear. The present results support this hypothesis because storage conditions which increased water loss also reduced the time for appearance of surface pitting. 'Van' cherries dipped in water prior and subsequent to impact damage showed substantial increases in the incidences of bruised and pitted f r u i t . The incidence of surface markings and surface pitting was significantly increased by a dip in water prior to impact damage. The water dipping procedure was designed to increase water content which hypothetically should have decreased the incidence of surface depressions. - 52 -However, soaking f r u i t prior and subsequent to bruising enhanced the development of surface damage disorders. Soaking f r u i t prior to impact damage may increase f r u i t turgor and frui t firmness (65) and result in increased c e l l fracture upon impact damage. Considine and Kriedman (17) observed a similar effect for rupture of grapes. Wade and Dewey (97) also found that internal browning of 'Schmidt' cherries resulting from bruising damage was increased by presoaking the frui t in water prior to bruising (Table 16). The increase in fr u i t damage associated with soaking f r u i t subsequent to impact is in direct contrast with the results of Wade and Dewey (97). Soaking cherries in water has been found to increase f r u i t turgor (95) and result in tissue rupture (16, 41, 95). Thus, cherry parenchyma cells which have been weakened by impact damage may rupture in response to increased f r u i t turgor caused by soaking after the injury occurred. Subsequently, due to cellular disruption, the cells w i l l collapse, in storage, and could result in normal pitting symptoms. The present results would indicate that the maintenance of high f r u i t turgor by placing fruit in direct contact with water could increase the expression of surface pitting symptoms. The incidence of fr u i t with surface markings and bruises was unaffected by storage humidity at 0°C or 20°C. Fruit stored at 20°C showed a marked reduction in the incidence surface markings and bruised f r u i t . Warm storage temperatures may allow damaged fr u i t tissues to recover. - 53 -Effects of Fruit and Storage Temperature on Surface Disorder Incidence Fruit temperature at the time of impact damage affected the rate of occurrence damage symptoms (Tables 17, 18). Fruit which was impact bruised when cold developed surface pitting symptoms much sooner than f r u i t which was bruised warm. However, the incidence of large surface pitting among f r u i t temperature treatments was not significantly different after 8 days at 0°C. Fruit temperature at the time of impact showed a slight negative correlation to the incidence of surface markings in the 1977 study but f r u i t temperatures were not significantly related to the incidence of surface marking in the 1978 study. The incidence of a l l surface markings, large and total surface pitting increased consistently with storage duration. The incidence of small pitting reached a maximum level at 4 days in storage. The apparent decreases in small surface pitting symptoms after 4 days of storage is likely due to small pits increasing in size and number and being classed as large pits. The influence of storage temperature on rate of development of damage disorders following impact was opposite to the effects of fru i t temperature at time of impact (Tables 19, 20). Fruit which was impact damaged at 0°C in 1977 and placed in 0° or 25°C storage developed lower incidence of surface pitting in 0°C after 5 days in storage. However, no significant differences in the incidence of surface pitting existed after 15 days of storage at 0°C. Fruit in the 1978 study showed that warm storage temperatures accelerated the development of surface pitting disorders, but storage temperatures were negatively correlated - 54 -to the incidence of f r u i t bruises after 16 days of storage which suggests that the tissues distorted in the formation of bruises may have either recovered their original shape or developed into surface pitting in warm storage temperatures. The incidence of a l l surface disorders except fru i t bruises increased with storage time. This evidence suggests that time is required for water loss from the region of damaged or collapsed cells for surface marking or pitting symptoms to develop. Warm storage temperatures would f a c i l i t a t e rapid water loss and account for the rapid occurrence of surface damage symptoms. Couey and Wright (18) and Porritt e_t a l . (70) observed fru i t temperatures to be negatively correlated to the incidence of cherry surface disorders after storage periods of 11 and 12 days respectively. The previous results do agree with the results in this study but the present data shows surface pitting disorders w i l l develop to the same extent for a l l f r u i t and storage temperatures in prolonged storage. The effects of fruits temperature in modifying the incidence of surface pitting may be due to greater elasticity of warm fr u i t tissues. Storage temperatures affect the rate of surface pitting development but do not markedly affect the total incidence of damage after prolonged storage. The impact received by the fr u i t is likely to cause a specific amount of cellular damage. Storage temperatures modify the rate at which symptoms appear but not the total amount of damage. Storage temperatures may modify the rate of pit development by influencing water loss from the damaged c e l l zone. Also when the enzymes of the cytoplasm and vacuolar substrates are mixed in ruptured cel l s , temperature - 55 -influences respiratory activity (55). Increased and uncontrolled enzymatic activity may attack nearby cells causing further cellular disruption. If the formation of surface pits is dependent upon additional cellular disruption after impact, then warm temperatures would f a c i l i t a t e enzymatic attack on cells adjacent to the damaged tissues thus increasing the amount of surface pitting. Effects of Maturity on Fruit Composition Fruit weight and soluble solids content increased with advancing f r u i t maturity (Tables 21, 22). These observations agree with those of Hartman (37) and Proebsting (77). At harvest, titratable acidity was highest in the least mature fr u i t in 1977 but showed no significant correlation with fru i t maturity in the 1978 study. The frui t soluble solids levels increased with advanced fru i t maturity. Fruit of intermediate maturity (No. 6) was softest in both years. Bioyield values were, however, unrelated to fru i t maturity. The drop in f r u i t firmness after No. 3 maturity corresponds to the time of rapid f r u i t swell in the stage III of growth (89) . The lowest levels of alcohol insoluble solids (Table 22) expressed on a fresh weight basis were correlated with minimum fr u i t firmness. Low values for firmness likely are attributable to rapid c e l l expansion with a slow rate of photosynthate accumulation as evidenced by low alcohol insoluble solids level. Cell structure would be weakened at this point in f r u i t development. - 56 -The percent dry matter increased linearly with advancing fr u i t maturity (Table 23). The differences observed in accumulation of dry matter and alcohol insoluble solids is likely due to the rapid accumulation of f r u i t sugars which are removed in the alcohol insoluble solids determination. The levels of soluble solids would not contribute to c e l l wall r i g i d i t y or the cellular 3-dimensional network strength. Mesocarp calcium, potassium and magnesium levels decreased with advancing frui t maturity when expressed on a dry weight basis (Table 24). However, only potassium and magnesium showed significant positive relationship to f r u i t maturity in 1977 when expressed on a fresh weight basis (Table 23). In the 1978 study, calcium, magnesium, and potassium a l l showed significant negative correlations with advancing fruit maturity when expressed on a dry weight basis (Table 25). Because dry weight increased linearly with advancing maturity the apparent decreases in mineral content may have resulted from a dilution effect. Expressed on a fresh weight basis f r u i t nitrogen decreased linearly with f r u i t maturity (Table 26). Concentrations of mesocarp calcium, magnesium, zinc and potassium reached minimum at intermediate maturities and appeared to increase with advancing maturity. The mineral accumulation and nitrogen dilution appear to be consistent with the hypothesis of accumulation of photo-synthate and c e l l wall material with advancing maturity. Cell walls and the middle lamella reinforced by accumulated alcohol insoluble solids would provide greater resistance to c e l l fracture and decreased incidences of damage disorders. - 57 -Water soluble and total pectin on a dry weight basis (Table 25) reached a maximurn about 7 days after the beginning of the stage III growth phase but decreased linearly on a fresh weight basis (Table 26). Cellulose content expressed on an alcohol insoluble solids basis was not significantly related to maturity. The maximum values recorded for total and water soluble pectin approximated the maturity at which minimum f r u i t firmness occurred. Histological Examinations of Disorder Incidence Microscopic examinations of impact damaged tissue indicated that f r u i t of No. 3 color maturity was susceptible to c e l l fracture (Fig. 18, 19). Cell rupture in No. 3 color maturities was evident immediately after impact even though surface dimpling had not occurred. The expression of surface pitting after 9 days of storage was evidenced by collapse and sunken appearance of the cells (Fig. 20). The present results agree with those of Porritt e_t a_l. (70) which indicated that surface pitting resulted from the collapse of cells 8-10 c e l l layers beneath the epidermis. Surface pitting appears to develop in storage as a result of volume loss from the region of fractured.cells allowing the outer c e l l layers to collapse inwards. Cherries of No. 33 color maturity did not develop surface pitting. Fruit parenchyma ce l l s , however, appeared to be distorted and form a flattened surface in response to impact damage (Fig. 21, 22). The flattened surface (bruise) was evident immediately upon impact - 58 -damage and no progression of the disorder with storage was evident (Fig. 23). Mature cherry parenchyma cells did not rupture and hence cellular collapse to form surface pitting symptoms did not occur. Fruit tissue of No. 33 color cherries appears to have strengthened c e l l walls resistance to impact damage. Cellular distortion may result from disruption of the middle lamella complex which would allow individual cells to shift in a distorted 3 dimensional c e l l matrix. However, in f r u i t of No. 3 color maturity, the middle lamella complex may be stronger than the individual c e l l walls so that on impact, the c e l l walls fracture and the cells collapse rather than the middle lamella yielding to form a distorted cellular structure. Effects of Maturity on Impact Damage Expression The amount of surface markings and surface pitting due to mechanical damage decreased with maturity in the 1977 study (Table 27). The incidence of fru i t bruises, however, increased with increased fruit maturity. The increase in the incidence of f r u i t bruises witlr maturity may be a consequence of the f r u i t cells distorting but not collapsing in response to impact. A similar observation was made in the 1978 study (Table 28) where the maximum level of fr u i t with surface markings occurred at 14 days and surface pitting occurred at 7 days into stage III of fruit growth. At 7 days into stage III a minimum incidence of fru i t bruises was recorded. This inverse relationship between fr u i t bruises and surface pitting may describe c e l l resistance to fracture. Cells which fracture and collapse result in surface pitting. Cells which distort but are resistant to fracture result in f r u i t bruises. - 59 -The maximum level of surface markings and surface pitting occurred in the i n i t i a l part of stage III of f r u i t , associated with rapid c e l l enlargement (89). Cell weakening caused by rapid fru i t enlargement apparently predisposes f r u i t to surface pitting. High proportions of nitrogen, total pectin and soluble pectin and low alcohol insoluble solids may contribute to c e l l fracture rather than c e l l distortion. High levels of f r u i t nitrogen have'been shown to result in f r u i t c ells which are relatively unstable in storage (30, 56, 57). High levels of pectin would result in a firm middle lamella creating a rig i d 3 dimensional structure which would absorb energy on impact without damage. Low levels of alcohol insoluble solids would indicate limited concentration of c e l l wall components. As cellulose appears to be unaffected by maturity, the fluctuation in alcohol insoluble solids with maturity appears to be attributable to the hemicellulose fraction (32, 100). Cell wall structures weakened by limited hemi-cellulose content would tend to fracture readily under stress. Accumulation of c e l l wall components with advancing maturity would strengthen c e l l walls and provide cellular resistance to fracture. Potassium accumulation on a fresh weight basis may also contribute to increased c e l l turgor, due to osmotic effects. Increased c e l l turgor may result in firmer f r u i t tissue and may provide resistance to cellular fracture and collapse. Effects of Work, Deformation and Loading Rate on Fruit Damage Incidence Increasing the work done on the fru i t from free f a l l increased the incidence of f r u i t bruises and surface pitting but decreased the - 60 -incidence of surface markings (Table 29, 30) for 3 f r u i t maturities. Surface markings appear to r e s u l t from compression forces such as a f r u i t being forced onto a stem. Bruises and surface p i t t i n g increase with increased work imparted to the f r u i t by impact. The inverse r e l a t i o n s h i p of surface markings to impact force may be due to the formation of bruises and surface p i t t i n g which mask smaller surface marks. Impact as measured by work done by free f a l l did not s i g n i f i c a n t l y a f f e c t the soluble s o l i d s l e v e l s at three maturities (Table 29) a f t e r 21 days storage. However, increasing the amount of impact work resulted i n a s i g n i f i c a n t decrease i n the t i t r a t a b l e a c i d i t y i n the f r u i t a f t e r storage. Increased l e v e l s of work done on the f r u i t resulted i n increased t i s s u e damage as evident by increased incidences of surface p i t t i n g . Increased amounts of tis s u e damage may be p o s i t i v e l y correlated with r e s p i r a t i o n rates (55) which may u t i l i z e a greater portion of acid substrate thus accounting for decreased t i t r a t a b l e a c i d i t y . The impact work on the f r u i t did not a f f e c t firmness or b i o y i e l d a f t e r storage f o r No. 3 or 33 color maturity but was p o s i t i v e l y correlated with f r u i t firmness and b i o y i e l d a f t e r storage i n f r u i t of No. 6 maturity. The firming e f f e c t of increased impact loads may be si m i l a r to that observed by Parker e_t al_. (65) , Labelle e_t al_. (44) in Montmorency c h e r r i e s . Repeated bruising of sour cherries was found to r e s u l t i n c a l l u s formation (27) which strengthened the f r u i t tissue i n storage. - 61 -Height of free f a l l was positively correlated with the incidences of bruises as well as large and total pitting in a 1978 study (Table 30). Fruit dropped on to a rough fiber belt developed higher incidences of surface markings and surface pitting than fruit dropped on to a smooth plastic belt while the development of bruises was unaffected by the type of belting material. The incidence of surface markings decreased as the drop distance to a rough belt increased. This evidence supports the hypothesis that surface markings result from compression of the fruit on a rough or small object. Impact pressures and frui t c o l l i s i o n with smooth surfaces do not aggravate this marking disorder. However, rough . surfaces and increased impact energies enhance the expression of surface pitting. Rough surfaces would provide many individual pressure points of impact with a cherry. The result would be that impact pressures would be concentrated on specific locations within the cherry f r u i t . This phenomenon would be conducive to c e l l rupture because greatly increased impact pressures would be exerted on specific c e l l tissue. Fruit contacting a smooth surface would have the energy of impact distributed more evenly across the f r u i t surface and internal tissues which would cause less c e l l fracture and decreased incidence of surface pitting. The development of damage disorders appears to be a function of the bruising surface texture, the degree of fr u i t deformation and the loading rate (Table 31). Surface pitting showed a positive relationship to the amount of deformation of the frui t and the loading rate of a f l a t plate. Fridley et a l . (34) indicated that maximum shear stress would correspond to the observed areas of c e l l collapse (Figs. 21, 22) which - 62 -result in surface pitting symptoms. The model of the cherry fruit when subjected to deformation may be described as a series dashpot arrangement (34). Cherry f r u i t w i l l exhibit viscoelastic properties when deformed. Slow loading rates applied to cherry fruits w i l l allow the cherry matrix to distort and flow in response to pressures exerted. However, large deformations of 4 to 8 mm may compress the parenchyma cells against the pit causing c e l l fracture. Similarly f r u i t tissue subjected to very fast loading rates (1000 mm/min) is not able to flow and distort fast enough in response to the pressure applied. Consequently, very fast loading rates may readily cause c e l l fracture at a l l deformations studied. The incidence of bruised f r u i t is unaffected by the loading rate or texture of the bruising surface. Fruit bruises result from permanent cellular distortion. The amount of cellular deformation therefore appears to be c r i t i c a l in determining whether the cells are to remain permanently distorted. The distortion of f r u i t cells must exceed a yield point with applied pressure beyond which the cells are unable to resume their original formation. A yield point may correspond to rupture of the middle lamella complex which is largely responsible for maintenance of the cellular 3-dimensional structure (32). Effects of Fruit Size on Fruit Composition and Damage Disorder Incidence Large f r u i t at a l l maturities showed significant reductions in the incidence of large and total pitting (Tables 32, 33). Cherry fruit subjected to a free f a l l with height adjusted to fr u i t weight to result in a constant work done on the f r u i t , showed similarly that large fruit - 63 -was resistant to surface pitting (Tables 32, 33). The incidence of f r u i t bruises were inversely related to fru i t size in 1977, but incidence of fru i t bruises and surface markings were unaffected by fru i t size and drop height in the 1978 study (Table 33). The effect of fr u i t size on surface damage does not appear to be related to factors such as alcohol insoluble solids, total or water soluble pectin, calcium, magnesium, potassium or zinc content when expressed on a fresh weight basis (Table 34). However, when fr u i t mineral content is expressed on a dry weight basis (Table 35) large f r u i t had significant lower levels of calcium, magnesium, potassium and zinc. Fruit nitrogen content on a fresh or dry weight basis was significantly lower in larger f r u i t than in smaller f r u i t . The tendency of smaller f r u i t to be more susceptible to c e l l fracture and surface pitting may be attributable to high f r u i t nitrogen. Fruit high in nitrogen has been found to be of low quality and are subject to cellular breakdown and loss of firmness (30, 56, 57). Stanberry and Clore (86) observed decreased incidence of surface pitting in 'Bing' cherries when f e r t i l i z e d with ground applications of nitrogen. Proebsting (77) also indicated that increased susceptibility to surface pitting may result from nitrogen deficiency. In this study, however, f r u i t nitrogen decreased with advancing maturity, and resistance to surface pitting disorders increased. F e r t i l i z a t i o n practices in the Okanagan indicate the use of 4 times are nitrogen than was used by Stanberry and Clore (86). This degree of nitrogen excess may predispose f r u i t to impact damage. - 64 -The incidence of surface markings (Tables 32, 36) was not related significantly to f r u i t weight. Surface markings appear to be superficial damage which is unlikely to be influenced by frui t nitrogen. The incidence of bruises, however, was less in small than in large fru i t in the 1977 study (Table 36). This may be attributable to the greater incidence of large pits found in small f r u i t . Fewer bruises but higher incidence of surface pits in small f r u i t may result from a greater tendency of cells to fracture in response to impact pressures, whereas in large f r u i t the cells tend to distort-and form bruises. Effects of Preharvest Sprays on Fruit Composition and Incidence of Damage Disorders Preharvest sprays of gibberellic acid (GA) significantly reduced the incidence of large and total surface pitting in 1977 and 1978 (Tables 37, 38). Gibberellic acid concentration in range of 20 to 30 ppm significantly reduced the incidence of surface pitting in fr u i t of No. 3 and 6 color maturities which agrees with results of Proebsting (77) . GA sprays significantly increased alcohol insoluble solids and significantly decreased total nitrogen from control values (Table s 39, 40). Increased alcohol insoluble solids may impart greater c e l l wall strength and resistance to fracture and may provide increased f r u i t firmness detected by Proebsting et_ a l . (76) . A decrease in fr u i t nitrogen on fresh and i dry weight bases is similar to that observed in large fru i t which also - 65 -is resistant to surface pitting. GA sprays had no significant effect on superficial surface markings or incidence of bruising in No. 3 color maturity fruit, but reduced bruising in the more mature No. 33 fr u i t color maturity in the 1977 study. Mobileaf sprays applied preharvest significantly increased f r u i t susceptibility to bruises, and surface markings in the second harvest and large and total pitting in the f i r s t harvest (Table 37). Langer and Fisher (46) reported that antitranspirant films applied to fruit as a preharvest spray significantly decreased dry matter. Susceptibility of cherries to mechanical damage was found in the current study to be negatively related to the alcohol insoluble solids content of the f r u i t . Decreased dry matter resulting from a Mobileaf spray could therefore account for increased susceptibility to mechanical damage. Effects of Reducing Crop Load on Fruit Characteristics and Susceptibility to Mechanical Damage Reducing crop load in two orchards gave variable results (Tables 41, 42). Fruit thinning on individual branches had no significant effect on soluble solids, bioyield, f r u i t firmness or titratable acidity of the f r u i t . Fruit weight, and alcohol insoluble solids content were significantly increased in f r u i t from branches which had been thinned in Orchard 1. Thinning had no effect on fr u i t composition in Orchard 0. - 66 -However, after the thinning was completed in Orchard 0, an extensive spontaneous f r u i t drop occurred which also reduced the crop on control branches. The results indicate that thinning may be beneficial only when a f u l l crop or overcropping occurs. Where thinning failed to affect f r u i t chemical and physical characteristics there was also no effect on resistance to impact damage. Thus thinning in Orchard 0 had no influence on the incidence of fruit bruises (Table 42). Thinning treatments showed significant reductions in the incidence of surface markings, large and total surface pitting. Resistance of f r u i t to surface pitting associated with reduced crop loads agrees with the general observations shown in Fig. 3. Crop reductions may impart f r u i t resistance to mechanical damage by increasing f r u i t size and alcohol insoluble solids content. Large f r u i t , mature fru i t with high alcohol insoluble solids and f r u i t sprayed with GA have been shown to be resistant to surface pitting. Reducing crop loads contributes to the development of this type of f r u i t by providing for greater photosynthate accumulation per f r u i t . Greater amounts of c e l l wall material would provide stronger f r u i t cells which would resist c e l l fracture. Stronger parenchyma cells resulting from photosynthate fo r t i f i c a t i o n also would account for the increased f r u i t firmness associated with the crop reduction. - 67 -SUMMARY AND RECOMMENDATIONS The amount and severity of impact collisions to the fruit were found to be the primary determinant of surface damage. However, previous results have shown that fru i t damage w i l l occur even with the minimum of f r u i t handling. The present study has described the pre- and postharvest treatments that are able to affect the expression of surface disorders in cherry f r u i t . The results provide the following conclusions and recommendations which when applied could minimize surface disorders resulting from mechanical damage in sweet cherries. 1. The application of preharvest sprays of 0.5% calcium chloride was effective in reducing susceptibility of fr u i t to mechanical damage. Sprays closest to harvest and multiple sprays were most effective in providing f r u i t resistance to surface pitting and bruises. 2. Postharvest calcium chloride dips were effective in increasing f r u i t firmness and bioyield values and in imparting resistance to mechanical damage to f r u i t . Firming of the f r u i t and decreasing f r u i t susceptibility to mechanical damage are not cause and effect but rather, coincidental factors resulting from dipping. Calcium uptake from a postharvest dip is best fitted by a logarithmic equation. Fruit uptake of calcium is enhanced by the addition of a thickener to the dipping solution, prolonged contact of fr u i t with dipping solution and the adjustment of the pH to 7. - 68 -3. Fruit susceptibility to surface damage is greatly decreased by a delay in 0°C storage for periods of 2-8 days before impact bruising of f r u i t . A delay in storage prior to impact damage enhanced the effect of a postharvest calcium chloride dip in prevention of damage symptoms. 4. Gibberellic acid sprays prior to harvest were effective in preventing mechanical damage to f r u i t . Preharvest gibberellic acid sprays resulted in f r u i t with higher alcohol insoluble content and lower nitrogen content. 5. The susceptibility of frui t to mechanical damage reached a maximum value between No. 3 to No. 6 color maturity. Mature mahogany fr u i t (color maturity No. 33) were the least susceptible to mechanical damage. As fr u i t developed i t became most suceptibility to mechanical damage at the time of i n i t i a l f r u i t swell in stage III of development. Lower levels of alcohol insoluble solids and higher nitrogen levels were associated with f r u i t of high predisposition to surface damage. 6. Large f r u i t was less susceptible to mechanical damage than small f r u i t . This effect was not related to maturity or alcohol insoluble solids content. However, large f r u i t had lower nitrogen values than did the smaller f r u i t . 7. Fruit which was bruised when cold developed more surface disorders earlier in storage than did f r u i t which was damaged when warm. Damaged fr u i t developed surface symptoms at a greater rate when stored in warm temperatures than in cold storage. The total amount of surface damage after 8-12 days of storage, however, was unaffected by frui t or storage temperatures. - 69 -8. Surface pitting develops as a result of a combination of loading rate and total force exerted on the f r u i t . Rapid loading rates w i l l produce damage at very low forces. Slow loading rates, however, require much higher forces to cause surface pitting. Cell disruption at time of impact appears to be necessary for disorders to develop in storage. 9. Low relative humidity in storage (40%) increased the rate of disorder development. However, storage humidity had no effect on the incidence of surface disorders after 16 days of storage. High temperature interacted with low storage humidity to give the most rapid development of surface disorders. The development of surface pitting and bruises are a function of weight loss and may be the result of localized water loss from the f r u i t . Fruit dipped in an antitranspirant (Mobileaf) designed to restrict water loss, reduced the expression of surface disorders. Soaking treatments prior to storage designed to increase f r u i t turgor, however, increased disorder incidence. 10. Reducing crop load on trees by hand thinning had variable results in benefiting f r u i t texture and decreasing fr u i t susceptibility to mechanical damage. However, hand thinning of trees which were heavily set did reduce susceptibility to mechanical damage. 11. Microscopic examinations revealed that c e l l fracture was apparent immediately after mechanical damage. The development of surface pitting requires time for redistribution of c e l l contents or loss of water from the region of cellular damage. Micrographs confirmed that impact forces caused tissue damage that resulted in surface pitting. - 70 -The possible handling and storage procedures which could be used by the commercial f r u i t industry to minimize losses due to mechanical damage in 'Van' cherries would be as follows: One spray of 30 ppm gibberellic acid or three sprays containing calcium chloride should be applied with the f i n a l spray applied within one week of harvest. Crop load should be limited by restricting amount of insect pollination, hand or chemical thinning or by more detailed pruning. It i s most preferable to have large fruits without high nitrogen levels. Excessive f e r t i l i z i n g with nitrogenous compounds i s , therefore, undesirable. Urea sprays should be avoided. Fruit should be harvested with care when mature, at least No. 6 color. Fruit received at the packing-house could be dipped in a solution of 4% calcium chloride plus 0.25% thickener plus 0.1% surfactant with pH adjusted to between pH 4 to 7. The fru i t then may be either: 1) packed immediately when the fru i t is s t i l l warm, cooled to below 5°C immediately and then shipped to arrive and be sold at the market within 4-6 days of packing, or, 2) the f r u i t which cannot be handled in this time frame may be cooled immediately to 0°C and packed after 4-8 days in cold storage at which time susceptibility to damage is reduced. With proper handling and 0°C storage cherries retain premium dessert condition for 3 to 4 weeks after harvest. Under no circumstances should f r u i t be in contact with surface water for prolonged periods as this w i l l increase disorder incidences. In a l l cases, the fruit should be kept at temperatures below 5°C and at storage relative humidities of greater than 85% RH. - 71 -These procedures make i t possible to reduce the incidence of surface disorder from greater than 70% to less than 10%. An improvement in condition of this magnitude combined with proper fungicide applications to restrict^ decay w i l l ensure the arrival of cherries on the most distant markets with less than the 15% allowable defects. LITERATURE CITED Archibald, J.A. and R.A. Cline. 1962. Factors affecting leaf-nutrient composition of Montmorency cherry. Ont. Hort. Soc. Rep. 1: 39-41. Arnold, CE. and A.E. Mitchell. 1970. Histology of blemishes of cherry fruits, (Prunus cerasus L., cv. Montmorency) Resulting from mechanical harvesting. J. Amer. Soc. Hort. Sci. 95: 723-725. Avery, D.J. and CA. Priestly. 1977. Carbon Resources. Influence of supply and demand. East Mailing Res. Stn. Rep. 1977: 168. Baker, G.L. 1948. 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State Hort. Proc. 69: 147-152. Table 1. Yearly cherry claims and returns. Year Total fresh volume sold (cases^) Total fresh return ($) Total fresh claim ($) Average claim (0/kg) Average grower return (C/kg) Expected grower return without claims (C/kg) Percent reduction of grower return by claims (%) 1974 348,922 2,934,318 257,151 7.94 56.10 64.04 12.3 1975 469,749 3,678,564 461,787 10.55 34.12 44.67 23.7 1976 511,059 3,707,977 529,589 11.23 31.02 42.25 26.6 1977 484,562 3,991,791 79,159 1.69 51.26 52.95 3.3 1978 333,985 4,015,386 225,000 7.26 86.88 94.14 7.7 B.C. Tree Fruits Ltd. production figures One case = 9.3 kg Table 2. Approximate cherry production handled by B.C. Tree Fruits Ltd. 1975 1976 1977 1978 Cultivar y No.of cases % of yearly total No.of cases % of yearly total No.of cases % of yearly total No.of cases % of yearly total Van 151,361 32.9 163,664 32.5 117,116 25.3 117,380 36.0 I i- 1 Bing 90,425 19.7 72,739 14.4 87,895 19.0 60,907 18.7 1 Lambert 213,885 46.5 263,564 52.3 258,273 55.8 147,999 45.4 B.C. Tree Fruits Ltd. production figures One case = 9.3 kg - 82 -Table 3. Effect of contact time with postharvest dip on calcium uptake by 'Van' cherries, 1978 crop. Time in dip Mesocarp calcium (min) (mg/kg) 0.25 666Z 1.0 667 4.0 671 16.0 688 64.0 755 128.0 844 z Values fitted from regression equation: Mesocarp calcium = 665.7 + 1.39 Time o (r = 0.76, p = 0.01). Flesh Calcium of undipped control = 578 ppm Table 4. E f f e c t s of f r u i t delay i n storage and a C a C l 2 dip containing thickener on disorder incidence i n 'Van' cherries, 1977 crop. Delay p r i o r to impact damage (days) CaCl plus thickener dip F r u i t with surface marks (%) Bruised f r u i t (%) F r u i t with < 5 mm diameter p i t t i n g (%) F r u i t with > 5 mm diameter p i t t i n g (%) Pi t t e d f r u i t (%) 0.5 0 27.4 Z 35.6 y 10. i x 40.1 52. 5 V 4 0 27.4 35.6 6.1 17.0 21.4 8 0 27.4 35.6 4.8 9.3 14.6 12 0 27.4 35.6 4.0 4.8 9.1 0.5 1 11.4 39.8 10.1 21.8 29.7 4 1 11.4 27.3 6.1 13.2 13.5 8 1 11.4 23.1 4.8 3.8 8.1 12 1 11.4 20.7 4.0 1.2 5.0 2 z Values f i t t e d from regression equation: F r u i t with surface marks = 27.4 - 16.0 Dip (r = 0.60, p = 0.01). y Values f i t t e d from regression equation: Bruised f r u i t = 35.6 - 13.8 Dip x Log (days delay) ( r 2 = 0.34, p = 0.01). x Values f i t t e d from regression equation: F r u i t with < 5 mm diam p i t t i n g = 8.8 - 4.42 Log (days delay) ( r 2 = 0.42, p = 0.01). w Values f i t t e d from regression equation: F r u i t with > 5 mm diam p i t t i n g = 32.4 - 15.1 Dip - 25.6 Log (days delay) + 10.7 Dip x Log (days delay) ft 2 = 0.95, p = 0.01). v Values f i t t e d from regression equation: P i t t e d f r u i t = 43.0 - 18.7 Dip - 31.4 Log (days delay) + 13.5 Dip x Log (days delay) (R 2 = 0.93, p = 0.01). Table 5. E f f e c t s of f r u i t delay i n storage, C a C l 2 and thickener dip on disorder incidence i n 'Van' cherries, 1978 crop. Days p r i o r to impact damage (days) z y X w 1.0 2.0 A.O 8.0 16.0 1.0 2.0 4.0 8.0 16.0 1.0 2.0 4.0 8.0 16.0 1.0 2.0 4.0 8.0 16.0 CaCl. dip 0 0 0 0 Thickener dip F r u i t with surface marks C O F r u i t with Bruised < 5 mm f r u i t diameter p i t t i n g (%) <%) 7.4' 7.4 7.4 7.4 7.4 7.4 7.2 6.7 5.2 1.4 7.4 7.4 7.4 7.4 7.4 7.4' 7.2 6.7 5.2 1.4 7.7' 5.8 4.0 2.1 0.0 7.7 5.8 4.0 2.1 0.0 7.7 5.8 4.0 2.1 0.0 7.7 5.8 4.0 2.1 0.0 14.4* 14.0 13.3 11.9 9.1 14.4 14.0 13.0 11.9 9.1 9.4 9.0 8.0 7.9 5.1 9.4 9.0 8.0 7.9 5.1 F r u i t with > 5 ran Pitted diameter p i t t i n g f r u i t (%) « ) 30.4 21.2 16.6 8.2 13.4 30.4 21.2 16.6 8.2 13.4 30.4 21.2 16.6 8.2 13.4 22.7 13.5 8.9 0.5 5.7 48.3 41.5 30.2 18.7 24.8 48.3 41.5 30.2 18.7 24.8 42.8 36.0 24.7 13.2 19.3 28.3 22.4 13.1 5.5 19.3 oo Values f i t t e d from regression equation: F r u i t with surface marks » 7.4 - 0.31 Log (day delay) x CaCl x Days delay (r = 0.16, p = 0.01) 2 Values f i t t e d from regression equation: Bruised f r u i t = 7.7 - 6.2 Log (day delay) (r = 0.31, p = 0.01) 2 Values f i t t e d from regression equation: F r u i t with less 5.mm diam p i t t i n g = 14.7 - 0.35 Day delay - 5.0 Thickener (R = 0.39, p = 0.01) Values f i t t e d from regression equation: F r u i t with greater 5 mm diam p i t t i n g = 47.2 - 16.8 Days delay - 7.68 CaCl x.Thickener + 16.0 Log (day delay) + 11.2 Log (day delay) x day delay (R" = 0.78, p = 0.01) Values f i t t e d from regression eo,ation: Pit t e d f r u i t - 70.8^22.5 ft***^*™^ I ^ i Z ^ l ^ - f ^ Table 6. E f f e c t of pH of postharvest calcium chloride dip on calcium uptake by 'Van' cherries, 1978 crop. Mesocarp Ca content (mg/kg) pH of dipping s o l u t i o n Days from dip 1 4 7 10 12 864 Z 910 920 894 857 934 1120 1160 1050 905 16 1210 1940 2100 1690 1090 00 z Values f i t t e d from regression equation: 2 Mesocarp calcium = 841.2 + 25.2 pH x Days - 1.99 pH x Days (R 2 = 0.82, p = 0.01). Table 7. Effects of preharvest CaCl 2 tree sprays on cherry mineral content, 1977 crop Mesocarp Mesocarp Mesocarp Mesocarp Ca Mg K Zn Treatment (mg/kg) (mg/kg) (mg/kg) (mg/kg) No tree spray 762 b Z 653 a 9309 a 6.0 a 1 tree spray 760 b 653 a 10450 a 6.9 a 0.5% CaCl-, 3 tree sprays 853 a 666 a 10140 a 5.7 a 0.5% CaCl-, Mean separation within a column by Newraan-Keuls test, 5% leve Table 8. Effects of dipping 'Van' cherries in a CaCl 2 dip solution on f r u i t bioyield and frui t firmness. No thickener in dip, 1977 crop. Dip Time (min) No dip 0.25 10 60 120 240 Mesocarp Ca (mg/kg) 511 695 865 957 1003 1126 y Predicted bioyield (kg) 0.76 0.88 0.99 1.05 1.08 1.16 Actual bioyield (kg) 0.80 0.85 0.88 1.00 1.04 1.13 Predicted firmness (kg/cm) 1.66 1.91 2.18 2.32 2.37 2.56 Actual firmness (kg/cm) 1.67 1.77 2.05 2.41 2.46 2.73 z Dip solution contained 30 g/1 CaCl 2, 1 g/1 nonionic surfactant, 0.5 g/1 Benlate. 2 y Values fitted from regression equation: Bioyield = 0.428 + 0.00065 Ca (r = 0.86, p = 0. 2 x Values fitted from regression equation: Firmness = 0.877 + 0.0015 Ca (r = 0.88, p = 0.0 Table 9. Effects of and fruit dipping 'Van' cherries in a CaCl„ firmness. Thickener in dip, 1977 dip crop solution on fr u i t bioyield Dip Time (min) Mesocarp Ca (mg/kg) y Predicted bioyield (kg) Actual bioyield (kg) Predicted X firmness (kg/cm) Actual firmness (kg/cm) No Dip 511 0.76 0.85 1.66 1.73 0.25 957 1.05 1.00 2.32 2.11 10 972 1.06 0.98 2.34 2.25 60 1080 1.13 1.10 2.49 2.67 120 1188 1.20 1.18 2.67 2.66 240 1295 1.27 1.32 2.82 3.50 Dip solution contained 30 g/1 CaCl-, 1 g/1 nonionic surfactant, 0.5 g/1 Benlate. 2 Values fitted from regression equation: Bioyield = 0.428 + 0.00065 Ca (r = 0.86, p = 2 Values fitted from regression equation: Firmness = 0.877 + 0.0015 Ca (r = 0.88, p = Table 10. Effects of CaCl„ tree sprays on cherry f r u i t firmness, 1977 crop. Treatment Bioyield at harvest (kg) Bioyield after storage (kg) Mesocarp f irmness at harvest (kg/cm) Mesocarp f irmness after storage (kg/cm) No tree spray 0.81 a Z 0.83 a 1.29 b 1.52 a 1 tree spray 0.79 a 0.78 a 1.35 b 1.37 a 0.5% CaCl 2 3 tree sprays 0.90 a 0.91 a 1.69 a 1.53 a 0.5% CaCl 2 Mean separation within a column by Newman-Keuls test, 5% level. Table 11. Effects of preharvest CaCl-, tree sprays on the incidence of cherry fru i t disorders, 19.77 crop. Treatment Fruit with bruises (%) Fruit with surface marks (%) Fruit with < 5 mm diameter pit (%) Fruit with > 5 mm diameter pit (%) Fruit with pitting (%) No tree spray 33.9 b Z 30.5 a 3.5 a 60.6 a 64.1 a 1 tree spray 57.3 a 32.7 a 1.1 a 37.3 b 38.4 b 0.5% CaCl-3 tree sprays 50.6 a 35.4 a 2.6 a 41.0 b 43.2 b 0.5% CaCl 2 z Mean separation within a column by Newman Keuls test, 5% level. E f f e c t s of p r e h a r v e s t C a C l 2 t r e e s p r a y s on t h e i n c i d e n c e o f c h e r r y f r u i t d i s o r d e r s , Treatment F r u i t c h a r a c t e r i s t i c s 0.35% C a C l , s p r a y 5 wks p r i o r t o h a r v e s t 0.35% C a C l 2 s p r a y 3 wks p r i o r t o h a r v e s t 0.35% C a C l 2 s p r a y 1 wk p r i o r t o h a r v e s t B r u i s e d f r u i t (%) F r u i t w i t h s u r f a c e marks (%) F r u i t w i t h < 5 mm d i a m e t e r p i t t i n g (%) F r u i t w i t h > 5 mm d i a m e t e r p i t t i n g (%) P i t t e d f r u i t «) F r u i t f i r m n e s s (kg/cm) B i o y i e l d (kg) 4 .0a Z 4.8a 9.8a 70.5a 80.3a 2.25b 1.78a + _ _ 5.3a 12.0a 11.8a 59.8b 71.5a 2.74ab 1.80a + _ A.3a 7.5a 15.3a 57.3b 72.5a 2.41b 2.04a + 5.3a 10.3a 13.0a 51.5b 67.0ab 2.84ab 1.69a + + 3.5a 6.5a 10.0a 48.0b 58.0b 3.09a 1.96a + + + 5.3a 10.5a 17.3a 21.8c 39.0c 3.29a 2.09a h - 1 Z Mean s e p a r a t i o n w i t h i n a column by Newman-Keuls t e s t , 5% l e v e l . Table 13. Effects of pH and CaCl postharvest dip on disorder incidence in 'Van' cherries, 1978 crop. Fruit with Fruit with pH of Fruit with Bruised < 5 mm > 5 mm Pitted solution surface marks fruit diameter pitting diameter pitting Fruit (%) (%) (%) (%) W 1 4.0Z 5.9y 6.5X 16. 6 W 27. 9 V 4 5.7 10.2 12.1 22. 8 18. 4 7 7.3 13.6 17.6 27. 5 22. 8 10 9.0 16.9 23.1 32. 2 34. 8 12 10.0 19.1 26.8 35. 0 44. 1 z Values fitted from regression equation: Surface marks = 3.5 + 0.545 PH ( r 2 = 0.19, p = 0.01). y Values fitted from regression equation: Bruised fr u i t = 5.8 + 1.11 pH ( r 2 = 0.61, p = 0.01). X Values fitted from regression equation: Fruit with < 5 mm diam pitting = (r 4.7 + 1 = 0.55, .84 pH p = 0.01). w Values fitted from regression equation: Fruit with > 5 mm diam pitting = ( r 2 16.6 + = 0.27, 1.56 pH p = 0.01) V Values fitted from regression equation: Pitted fruit = = 35.2 - 8.47 pH + 1. (R2 .22 pH2 = 0.82, - 0.0377 pH3 p = 0.01). T a b l e 14. E f f e c t s of s t o r a g e t e m p e r a t u r e and h u m i d i t y on weight l o s s and d i s o r d e r development i n 'Van' c h e r r y , 1978 c r o p . S t o r a g e F r u i t w i t h F r u i t w i t h S t o r a g e Days r e l a t i v e Weight F r u i t w i t h < 5 mm > 5 mm P i t t e d B r u i s e d t e m p e r a t u r e i n s t o r a g e h u m i d i t y l o s t s u r f a c e marks d i a m e t e r p i t t i n g d i a m e t e r p i t t i n g f r u i t f r u i t (°C) (%) (%) CO (%) U) (%) 1 2 4 8 16 0.103' 0.103 0.103 0.103 0.103 10.8 10.8 10.8 10.8 10.8 15.0 15.0 15.0 15.0 15.0 1.2 5.5 12.6 24.8 47.6 1. 15. 29. 45. 66. 14.8 14.8 14.8 14.8 14.8 1 2 4 8 16 1.945 1.945 1.945 1.945 1.945 10.8 10.8 10.8 10.8 10.8 15.0 15.0 15.0 15.0 15.0 0.0 12.8 27.1 41.4 55.7 14.6 27.7 40.7 53.8 66.9 14.8 14.8 14.8 14.8 14.8 vo 20 20 1 2 4 8 16 1 2 4 8 16 0.103 0.103 0.103 0.103 0.103 1.945 1.945 1.945 1.945 1.945 10.8 10.6 9.9 8.0 3.2 10.8 10.6 9.9 8.0 3.2 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 11.4 13.8 24.9 41.5 75.3 9.2 23.2 37.3 51.2 65.2 21.0 32.8 43.7 50.2 60.8 33.8 45.2 55.0 61.4 61.4 14.8 14.5 13.5 12.1 10.4 14.8 14.3 13.5 12.1 10.4 z R e l a t i v e h u m i d i t y v a l u e s coded a s : 0 = 95-100%RH, 1 = 40%RH. 2 y V a l u e s f i t t e d f r o m r e g r e s s i o n e q u a t i o n : Weight l o s t = 1.945 - 1.842 H u m i d i t y ( r = 0.28, p = 0.01) 2 x V a l u e s f i t t e d f r o m r e g r e s s i o n e q u a t i o n : S u r f a c e markings = 10.8 - 0.0196 Log (day) x day x t e m p e r a t u r e ( r = 0.20, p = 0.01) w v F r u i t w i t h < 5 mm diam p i t t i n g = 15.0 ( r e g r e s s i o n e q u a t i o n n o t s i g n i f i c a n t p = 0.01) V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : F r u i t w i t h > 5 mm diam p i t t i n g =-1.47 + 0.535 Temperature + 2.62 H u m i d i t y x day + 47.5 Log (day) - 41.6 Log (day) x h u m i d i t y - 0,0508 Log (day) x day x te m p e r a t u r e + 0.0474 Log (day) x h u m i d i t y x t e m p e r a t u r e x day ( R 2 = 0.90, p = 0.01) V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : P i t t e d f r u i t = 14.6 - 12.8 H u m i d i t y 2 + 1 04 Temperature - 0.0822 Day x t e m p e r a t u r e + 43.4 Log (day) + 0.635 Log (day) x h u m i d i t y x day (R = 0.85, p - 0.01) 2 V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : B r u i s e d f r u i t •» 14.8 - 0.0270 Log (day) x day x t e m p e r a t u r e ( r - 0.22, p = 0.01). Table 15. Effects of washing on effectiveness of postharvest dips in preventing damage disorders in 'Van' cherries, 1978 crop. Fruit with Fruit with Dipping Wash Fruit with Bruised < 5 mm > 5 mm Pitted solution time surface marks frui t diameter pitting diameter pitting fr u i t (%) <%) (%) <%) (%) Water None 11. 3 z a 4.8 c 16.8 abc 45.8 ab 62.5 a before bruising 12. 5 a 4.5 c 18.0 ab 44.3 abc 62.3 a after bruising 15. 0 a 3.0 c 14.0 bed 48.5 a 62.5 a 2.5 g/1 Keltrol None 15. ,8 a 4.3 c 12.3 bed 30.5 d 42.8 c before bruising 14. ,3 a 2.5 c 21.5 a 36.0 cd 57.5 a after bruising 17. ,0 a 10.0 a 11.5 bed 42.3 abc 53.8 ab 40 g/1 CaCl-, None 6. ,5 a 3.0 c 9.5 cd 31.8 d 41.3 c before bruising 7. ,5 a 2.3 c 16.5 abc 44.3 abc 60.8 a after bruising 14. .5 a 5.5 be 14.8 abc 45.3 abc 60.0 a 40 g/1 CaCl„ None 9. .8 a 3.2 c 8.3 d 21.3 e 29.5 d 2.5 g/1 Keltrol before bruising 10, .8 a 6.0 be 14.8 abed 30.8 d 45.5 c after bruising 7, .8 a 5.3 be 15.0 abed 27.3 de 42.3 c 1/5 (v:v) None 7, .0 a 2.5 c 8.3 d 20.0 e 28.3 d Mobileaf before bruising 14 .0 a 4.5 c 11.8 bed 36.5 bed 48.3 be after bruising 9 .5 a 9.5 ab 13.3 bed 29.3 d 42.5 c Mean separation, within columns, Newman-Keuls test, 5% level. Table 16. Effects of dipping duration on disorder incidence in 'Van1 cherry, 1978 crop. Fru i t with Fruit with Dipping Dipping Fruit with Bruised < 5 mm > 5 mm Pitted duration sequence surface marks f r u i t diameter p i t t i n g diameter p i t t i n g f r u i t (min) <%> (%) <*> <%> ( % ) 0 . 2 5 before impact ( 0 ) 16.3Z 7.8y 11.9 X 13. ,3W 24. 6V 4 . 0 it n 16.3 7.5 13.6 14. ,4 26. ,1 1 6 . 0 tr 16.3 6.7 16.5 17. ,8 29. ,9 6 4 . 0 it i i 16.3 5.3 41.3 26. .3 40. ,8 1 2 8 . 0 II • i 16.3 8.1 70.8 25. ,3 42. .5 0 . 2 5 after impact ( 1 ) 12.3 10.7 11.9 22. .9 34, .8 4 . 0 it 11 12.3 10.4 13.6 24. .1 36, .2 1 6 . 0 II n 12.3 9.6 16.5 27, .4 40 .0 6 4 . 0 rt 11 12.3 8.2 41.3 35, .9 50 .9 1 2 8 . 0 it 11 12.3 11.0 70.8 34 .9 52 .6 z Values fi t t e d from regression equation: Fruit with surface marks = 16.3 2 - 3.98 Sequence (r = 0.07, p = 0.01) 2 Values f i t t e d from regression equation: Bruised f r u i t = 7.8 - 0.0795 Duration + 2.94 Sequence + 0.000640 Duration (R 2 = 0.16, p = 0.01). 2 Values f i t t e d from regression equation: Fruit with < 5 mm p i t t i n g = 11.8 + 0.461 Duration (r = 0.14, p = 0.01). Values f i t t e d from regression equation: Fruit with > 5 mm p i t t i n g = 13.2 + 0.315 Duration + 9.63 Sequence -0.00172 Duration 2 ( r 2 = 0.49, p = 0.01). 2 Values f i t t e d from regression equation: Pitted f r u i t = 24.6 + 0.365 Duration + 10.1 Sequence - 0.00176 Duration (R 2 = 0.54, p = 0.01) . Table 17. Effects of handling temperature of fru i t on disorder incidence in 'Van' cherries, 1977 crop. Fruit with Fruit with Handing Fruit with < 5 mm > 5 mm Pitt temperature surface marks diameter pitting diameter pitting f r u i (°C) (%) (%) W (%) 0 40.1Z 28.7y 14.1X 42. 5 W 5 38.8 27.0 12.5 39.4 10 37.5 25.2 11.0 36.2 25 33.5 20.1 6.2 26.8 38 30.0 15.6 2.1 18.6 Values fitted from regression equation: Fruit with surface marking = 40.1 - 0.265 Handling temp ( r 2 = 0.16, p = 0.01). Values fitted from regression equation: Fruit with < 5 mm diam pitting = 28.7 - 0.346 Handling temp ( r 2 = 0.27, p = 0.01). Values fitted from regression equation: Fruit with > 5 mm diam pitting = 14.1 - 0.315 Handling temp ( r 2 = 0.31, p = 0.01). Values fitted from regression equation: Pitted f r u i t = 42.5 - 0.630 Handling temp ( r 2 = 0.34, p = 0.01). T a b l e I S . E f f e c t s of f r u i t t e m p e r a t u r e a t t i m e o f impact on d i s o r d e r development i n 'Van' c h e r r i e s , 1978 c r o p . F r u i t w i t h F r u i t w i t h Days F r u i t t e m p e r a t u r e F r u i t w i t h B r u i s e d < 5 mm > 5 mm P i t t e d i n s t o r a g e a t impact s u r f a c e marks f r u i t d i a m e t e r p i t t i n g d i a m e t e r p i t t i n g f r u i t (°C) (%) (%) (%) (%) (%) 1 0 2.6 2 7.0 y 3.6 X u 1.0 7.2 V 2 0 7.1 - 7.0 12.8 1.6 17.3 . 0 9.A 7.0 18.0 10.0 31.2 8 0 6.1 7.0 13.5 37.9 54.3 1 5 2.6 7.0 3.6 1.0 5.7 2 5 7.1 7.0 12.8 1.6 15.8 A 5 9.A 7.0 18.0 10.0 29.6 8 5 6.1 7.0 13.5 37.9 52.7 1 10 2.6 7.0 3.6 1.0 A . l 2 10 7.1 7.0 12.8 1.6 1A.3 A 10 9.A 7.0 18.0 10.0 28.1 8 10 6.1 7.0 13.5 37.9 51.2 1 20 2.6 7.0 3.6 1.0 1.0 2 20 7.1 7.0 12.8 1.6 11.2 A 20 9.A 7.0 18.0 10.0 25.0 8 20 6.1 . 7.0 13.5 37.9 A8.1 z V a l u e s f i t t e d f r o m r e g r e s s i o n e q u a t i o n : S u r f a c e marks = 2.6 + 18.8 Log (Day) - 1.86 Log(Day) x day (R = 0.41, p = 0.01) y R e g r e s s i o n e q u a t i o n n o t s i g n i f i c a n t (p = 0.01) B r u i s e d f r u i t = 7 . 0 (p > 0.01) 2 x V a l u e s f i t t e d f r o m r e g r e s s i o n e q u a t i o n : F r u i t w i t h < 5 mm diam p i t t i n g = 3.6 + 37.0 Log (Day) - 3.25 Log (Day) x day (R = 0.59, p = 0.01) 2 w V a l u e s f i t t e d f r o m r e g r e s s i o n e q u a t i o n : F r u i t w i t h > 5 mm diam p i t t i n g - 1.0 - 10.9 Log (Day) + 6.A7 Log (Day) x day (R = 0.96, p = 0.01) 2 v V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : P i t t e d f r u i t - 7.2 - 0.308 Temp + 27.5 Log (Day)+ 3.08 Log (Day) x day (R - 0.9A, p - 0.01) Table 19. Effects of storage temperature and time on incidence of storage disorders in 'Van' cherries, 1 9 7 7 crop. Storage temp. (°C) Time in storage (d) Fruit with surface marks Fruit with < 5 mm diameter pitting (%) Fruit with > 5 mm diameter pitting Pitted fr u i t (%) 0 25 0 5 5 15 34.3 a 39.2 a 30.9 a 18.8 b 25.2 a 13.0 b 7.5 c 31.0 b 40.9 a 26.3 b 56.2 a 53.9 a VO 00 Mean separation within a column by Newman-Keuls test, 5% level. T a b l e 20. E f f e c t s of s t o r a g e t e m p e r a t u r e o f 'Van' c h e r r i e s on d i s o r d e r development, 1978 c r o p . Days i n s t o r a g e S t o r a g e t e m p e r a t u r e (°C) F r u i t w i t h s u r f a c e marks (%) B r u i s e d f r u i t a) F r u i t w i t h £ 5 mm d i a m e t e r p i t t i n g (%) F r u i t w i t h > 5 mm d i a m e t e r p i t t i n g (%) P i t t e d f r u i t (%) 1 2 4 8 16 1 2 4 8 16 1 2 4 8 16 1 2 4 8 16 0 0 0 0 0 5 5 5 5 5 10 10 10 10 10 20 20 20 20 20 5.3" 9.1 11.9 13.6 13.2 5.8 9.1 11.9 13.6 13.2 5.8 9.1 11.9 13.6 13.2 5.8 9.1 11.9 13.6 13.2 6.7' 9.8 11.9 11.8 7.4 10.0 12.8 14.1 12.9 6.6 13.3 15.8 16.4 14.0 6.0 19.9 21.5 20.9 16.3 4.4 12. 15. 16. 14. 8.8 12.3 15.2 16.7 14.8 8.8 12.3 15.2 16.7 14.8 8.8 12.3 15.2 16.7 14.8 0.0 8.1 18.6 30.7 43.3 3.0 12.1 22.6 34.7 47.3 7.1 16.1 26.7 38.8 51.4 15.1 24.2 34.7 46.8 59.5 2.1 13.4 27.6 45.8 67.9 9.3 20.1 33.4 49.6 67.8 16.5 26.8 39.1 53.3 67.7 30.8 40.2 50.5 60.9 67.6 vO 2 z V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : S u r f a c e marks - 6.3 - 0.529 Day + 12.8 Log (Day) (R = 0.65, p = 0.01) y V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : B r u i s e d f r u i t = 7.8 - 1.07 Day + 0.758 Temp - 0.0971 Temp x day + 13.9 Log (Day) + 0.0336 Log (Day) x day x temp (R 2 = 0.56, p = 0.01) 2 x V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : F r u i t w i t h < 5 mm diam p i t t i n g = 8.8 + 12.6 Log (Day) - 0.476 Log (Day) x day (R = 0.49, p = 0.01) w V a l u e s f i t t e d f r o m r e g r e s s i o n e q u a t i o n : F r u i t w i t h > 5 mm diam p i t t i n g = -5.1 + 4.07 Day + 0.808 Temp + 21.0 Log (Day) - 2.18 Log (Day) x day (R2 = 0.77, p = 0.01) v V a l u e s f i t t e d f r o m r e g r e s s i o n e q u a t i o n : P i t t e d f r u i t » -4.6 + 6.74 Day + 1.53 Temp - 0.0965 Temp x day + 21.5 Log (Day) - 3.18 Log (Day) x day ( R 2 = 0.81, p = 0.01) T a b l e 21. E f f e c t s o f m a t u r i t y and s t o r a g e o f 'Van' c h e r r i e s on s o l u b l e s o l i d s , w e i g h t , t i t r a t a b l e a c i d i t y and f i r m n e s s , 1977 c r o p . M a t u r i t y F r u i t w e i g h t (g) S o l u b l e s o l i d s a t h a r v e s t (%) T i t r a t a b l e a c i d i t y a t h a r v e s t (mgMalic/100ml) S o l u b l e s o l i d s a f t e r s t o r a g e (%) T i t r a t a b l e a c i d a f t e r s t o r a g e (mgMalic/lOChnl) B i o y i e l d a t h a r v e s t (kg) F r u i t firmness (kg/cm) B i o y i e l d a f t e r s t o r a g e (kg) F r u i t firmness (kg/cm) 3 6 33 8.25c 7 9.19b 10.0a 15.3c 16.1b 17.9a 1009a 836b 837b 13.0c 15.3b 18.1a 868a 820a 844a 0.83a 0.83a 0.78a 1.55a 1.26c 1.47b 0.98a 0.79b 0.92a 1.64a 1.10b § 1.75a z C o l o r comparator q u a l i t a t i v e i n d i c e s o f m a t u r i t y . y Mean s e p a r a t i o n w i t h i n a column by Newman-Keuls t e s t , 5% l e v e l . T a b l e 22. E f f e c t s o f m a t u r i t y on f r u i t c h a r a c t e r i s t i c s i n 'Van' c h e r r i e s , 1978 c r o p . Days of s t a g e I I I o f f r u i t development F r u i t w e i g h t S o l u b l e s o l i d s T i t r a t a b l e a c i d i t y F i r m n e s s (kg/cm) B i o y i e l d (kg) A l c o h o l i n s o l u b l e s o l i d s (% f r e s h wt) o z 4.49 y 10.0X 818w 6.02 v 1.96u 2.505c 7 6.11 11.3 818 3.02 1.96 1.908 14 7.20 12.6 818 2.28 1.96 1.730 21 7.75 13.9 818 2.78 1.96 1.972 28 7.76 15.2 818 3.51 1.96 2.052 F r u i t development c o r r e s p o n d s t o c o l o r comparator q u a l i t a t i v e i n d i c e s o f : Day 7 (No. 3 ) , Day 14 (No. 6 ) , and Day 28 (No. 33) 2 2 V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : F r u i t wt = 4.488 t 0.2705 Days - 0.005485 Day (R = 0.87, p - 0.01) 2 V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : S o l u b l e s o l i d s = 10.0 + 0.184 Days ( r - 0.71, p = 0.01) R e g r e s s i o n e q u a t i o n not s i g n i f i c a n t . T i t r a t a b l e a c i d i t y = 818 (p>0.01) 2 3 2 V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : F i r m n e s s = 6.02 - 0.637 Days + 0.0333 Day - 0.000491 Days (R = 0.95, p - 0.01) R e g r e s s i o n e q u a t i o n n o t s i g n i f i c a n t . B i o y i e l d = 1.96 (p - 0.01) V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : AIS - 2.505 - 0.1777 Days + 0.01171 D a y s 2 - 0.0002122 D a y s 3 ( R 2 = 0.85, p - 0.01) Table 23 . Effects of maturity of 'Van' cherries on dry weight and mesocarp mineral content on a fresh weight basis. 1977 crop. Dry matter Flesh Ca Flesh K Flesh Mg Flesh Zn Maturity (%) (mg/kg) (mg/kg) (mg/kg) (mg/kg) 3 Z 15.7cY 139.8 a 1623 a 82.7 c 1.17 a 6 17.7 b 136.4 a 1693 a 106.6 b 0.84 a 33 20.9 a 138.0 a 1830 b 122.7 a 1.43 a z Color comparator qualitative indices of maturity. y Mean separation within a column by Newman-Keuls test, 5% level. Table 24. Effects of maturity of 'Van' cherries on mineral content of fr u i t mesocarp on a dry weight basis, 1977 crop. Mesocarp Ca Mesocarp K Mesocarp Mg Mesocarp Zn Maturity (mg/kg) (mg/kg) (mg/kg) (mg/kg) 3 Z 836 a y 10290 a 698 a 7.78 a 6 762 b 9309 ab 653 b 5.98 a 33 625 c 8680 b 592 c 7.20 a z Color comparator qualitative indices of maturity. y Mean separation within a column by Newman-Keuls test, 5% level. T a b l e 25. • E f f e c t s of m a t u r i t y on f r u i t c o m p o s i t i o n on a d r y w e i g h t b a s i s , 1978 c r o p . Days o f s t a g e I I I growth T o t a l p e c t i n (% AIS) Water s o l u b l e p e c t i n (% AIS) C e l l u l o s e (% AIS) T o t a l mesocarp N OS) Mesocarp Ca (mg/kg) Mesocarp Mg (mg/kg) Mesocarp Zn (mg/kg) Mesocarp K (mg/kg) 0 Z 25.5V 1 5 . 0 X 0.419" 7.25 v 1865" 1 1 7 8 c . 7.9 s 1 5 4 8 0r 7 28.5 16.0 0.419 6.23 1565 1035 7.9 12456 14 27.6 14.9 0.419 5.22 1264 891 7.9 11175 21 22.9 11.6 0.419 4.21 964 748 7.9 10548 28 14.2 6.3 0.419 3.19 664 604 7.9 10940 o 4> z F r u i t development c o r r e s p o n d s t o c o l o r comparator q u a l i t a t i v e i n d i c e s o f : Day 7 (No. 3 ) , Day 14 (No. 6 ) , and Day 28 (No. 3 3 ) . 2 2 y V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : T o t a l p e c t i n = 25.5 + 0.709 Days - 0.0397 Day (R - 0.66, p = 0.01) 2 2 x V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : Water s o l u b l e p e c t i n = 15.0 + 0.293 Days - 0.0216 Day (R » 0.76, p - 0.01) w R e g r e s s i o n e q u a t i o n not s i g n i f i c a n t . C e l l u l o s e = 0.419 (p > 0.01) 2 2 v V a l u e s f i t t e d f r o m r e g r e s s i o n e q u a t i o n : T o t a l mesocarp n i t r o g e n = 7.25 - 0.145 Day ( r - 0.63, p • 0.01) 2 u V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : Mesocarp c a l c i u m - 1865 - 42.9 Days ( r •» 0.68, p •» 0.01) 2 t V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : Mesocarp magnesium » 1178 - 20.5 Days ( r - 0.68, p » 0.01) s R e g r e s s i o n e q u a t i o n not s i g n i f i c a n t . Mesocarp z i n c = 7.9 (p > 0.01) 2 2 : V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n . Mesocarp p o t a s s i u m - 15480 - 452.8 Days + 10.38 Days (R ~ 0.70, p ° 0.01) T a b l e 26. E f f e c t s o f f r u i t m a t u r i t y on f r u i t c o m p o s i t i o n on f r e s h w e i g h t b a s i s , 1978 c r o p . Days o f s t a g e I I I growth T o t a l p e c t i n (%) Water s o l u b l e p e c t i n (%) T o t a l mesocarp N • . (%)•• Mesocarp Ca (mg/kg) Mesocarp Mg (mg/kg) Mesocarp Zn (mg/kg) Mesocarp K (mg/kg) Dry Weight (%) 0 Z 0.613? 0 . 3 5 6 x 1 . 3 1 7 w 2 3 0 v 128 u 1.43 c 2015 s 15.9 r 7 0.684 0.409 1.170 158 128 0.87 1736 17.1 . 14 0.756 0.461 1.036 135 128 0.83 1643 18.3 21 0.827 0.514 0.895 131 128 0.98 1736 19.5 28 0.899 0.567 0.754 156 128 1.44 2015 20.7 z F r u i t development c o r r e s p o n d s to c o l o r comparator q u a l i t a t i v e i n d i c e s o f : Day 7 (No. 3 ) , Day 14 (No. 6 ) , and Day 28 (No. 33) y V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : T o t a l p e c t i n = 0.613 - 0.0102 Days ( r2 - 0.74, p - 0.01) X V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : Water s o l u b l e p e c t i n = 0.356 - 0. 00752 Days ( r 2 = 0.90, p = 0.01) w V a l u e s f i t t e d f rom r e g r e s s i o n e q u a t i o n : T o t a l mesocarp n i t r o g e n = 1.317 - 0.0201 Days ( r 2 •= 0.52, p = 0.01) V V a l u e s f i t t e d f rom r e g r e s s i o n 2 e q u a t i o n : Mesocarp c a l c i u m = 230 - 10.9 Days + 0.295 Days ( R 2 - 0.67, p = 0.01) u R e g r e s s i o n e q u a t i o n not s i g n i f i c a n t . Mesocarp magnesium = 128 (p > 0.01) 2 2 t V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : Mesocarp z i n c = 1.43 - 0.0866 Days + 0.00310 Days (R - 0.44, p " 0.01) 2 2 s V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : Mesocarp p o t a s s i u m - 2015 - 53.11 Days + 1.897 Days (R - 0.73, p - 0.01) 2 r V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : Dry w e i g h t .= 15.9 + 0.170 Day ( r - 0.53, p - 0.01) Table 27. Effects of maturity and work done on cherry fru i t on the incidence of surface disorders, 1977 crop. Work done Fruit with Fruit with Fruit with Maturity (joules) Bruises surface marks pitting (%) <%) (%) 3 Z 3 3 3 0.00 0.02 0.04 0.08 5.4y 12.2 17.4 23.1 30.9X 28.6 26.4 21.8 8.4W 50.8 76.5 77.8 6 6 6 6 0.00 0.00 0.04 0.06 5.4 28.6 44.7 55.2 31.0 28.7 26.5 21.9 8.4 35.3 48.2 31.9 33 33 33 33 0.00 0.02 0.04 0.08 5.4 50.7 77.7 76.3 13.9 11.6 9.4 4.8 8.4 20.5 26.8 22.1 Color comparator qualitative indices of maturity. Color maturity of frui t coded as: Three - (1-0); Six = (0-1), Thirty-three (0-0). Values fitted from equation: Bruised fruit = 5.28 +2730 Work - 2349 Three x work + 2110C) Three x work r 1389 Six x Work + 14100 Six x Work - 23000 Work2 (R = 0.89, p = 0.01). w Values fitted from equation: Fruit with surface marking = 13.9 + 17.1 Three - 113.7 Work + 17.0 Six (RZ = 0.62, p = 0.01). Values fitted from equation: Fruit with pitting = 8.38 + 750 Work + 1788 ThreexWork - 13600 Three . (R2 = 0.95, p = 0.01). Table 28. Effects of maturity of 'Van' cherries on disorder incidence, 1978 crop. Fruit with Fruit with Days of stage III Fruit with Bruised < 5 mm > 5 mm Pitted of f r u i t development surface marks fruit diameter pitting diameter pitting fruit (%) (%) (%) (%) (>o o z 2.9y 21.6X 7 7.0 5.4 14 8.3 16.3 21 7.0 27.1 28 2.9 10.8 16.9W 17. 6 V 32.0' 14.1 58.3 74.8 11.3 47.2 60.8 8.5 18.0 26.4 5.7 4.1 8.2 z Fruit development corresponds to color comparator qualitative indices of: Day 7 (No. 3), Day 14 (No. 6), and Day 28 (No. 33) 2 y Values fitted from regression equation: Surface marks = 2.9 + 0.776 Days = 0.0277 Days (R = 0.37, p = 0.01) 2 3 x Values fitted from regression equation: Bruised f r u i t = 21.6 - 5.55 Days + 0.554 Days - 0.0132 Days (R2 = 0.76, p = 0.01) w Values fitted from regression equation: Fruit with < 5 mm diam pitting = 16.9 - 0.400 Days ( r 2 = 0.45, p = 0.01) v Values fitted from regression equation: Fruit with > 5 mm diam pitting = 17.6 + 11.1 Days - 0.870 Days + 0.0163 Days (R2 = 0.89, p = 0.01) 2 3 u Values fitted from regression equation: Pitted fruit = 32.0 + 11.9 Day - 0.951 Days + 0.0177 Days (R2 = 0.96, p = 0.01) Table 29. Effect of maturity and work done on f r u i t on soluble so l i d s , t i t r a t a b l e firmness and bioyield in 'Van' cherries, 197 7 crop. Maturity Work done (joules) y x w Soluble solids (%) Titratable acids (mgmalic/lOOml) Bioyield (kg) Firmness (kg/cm) 3 Z 0.00 ; 13.I y 840 X 3 0.02 13.1 834 3 0.04 13.1 817 3 0.08 13.1 747 6 0.00 15.8 840 6 0.02 15.8 834 6 0.04 15.8 817 6 0.08 15.8 747 33 0.00 18.1 840 33 0.02 18.1 834 33 0.04 18.1 817 33 0.08 18.1 747 2.19 2.19 2.19 2.19 1.75 1.81 1.87 1.99 2.05 2.05 2.05 2.05 3.55 3.55 3.55 3.55 2.44 3.07 3.43 3.31 3.87 3.87 3.87 3.87 o oo Color comparator qualitative indices of maturity. Color maturity of f r u i t coded as: Three = (1-0); Six = (0-1); Thirty-three = (0-0). 18.1 - 4.98 Three - 2.35 Six ( R 2 = 0.85, p = 0.01). 2 2 Values f i t t e d from equation: Titratable acids = 840 - 14600 Work (r = 0.38, p = 0.01). Values f i t t e d from equation: Bioyield = 2.05 + 0.137 Three - 0.298 Six - 3.04 Six x Work ( R 2 = 0.50, p = 0.01). Values f i t t e d from equation: Soluble solids Values f i t t e d from equation: Firmness = 3 . 8 7 0.324 Three - 1.43 Six + 38.6 Six x Work (R2 = 0.70, p •= 0.01). 3 4 6 Six x Work 13 25 51 102 13 25 51 102 T a b l e 30. E f f e c t s o f h e i g h t o f drop of c h e r r y and i n 'Van' c h e r r i e s , 1978 c r o p . impact s u r f a c e on d i s o r d e r i n c i d e n c e smooth smooth smooth smooth rough rough rough rough F r u i t w i t h F r u i t w i t h H e i g h t of drop (cm) Impact s u r f a c e F r u i t w i t h s u r f a c e marks C O -B r u i s e d f r u i t 00 < 5 mm d i a m e t e r p i t t i n g 00 > d i a m e t e r C O 5 mm p i t t i n g P i t t e d f r u i t 00 10. 10. 10. 10, 23.3 22.0 19.3 1A.0 2.3 3.7 6.6 12.4 2. 3. 6. 12. 14.0 14.0 14.0 14.0 14.0 14.0 14.0 14.0 5.6 13.0 27.9 57.7 22. 29. 44. 74. 15.V 24.4 42.5 78.7 38 46 61 85 O to ;z y X w v u Impact s u r f a c e coded as: Smooth = 0; Rough = 1. 2 V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : F r u i t s w i t h s u r f a c e marks = 10.9 + 13.7 S u r f a c e - 0.104 S u r f a c e x h e i g h t (R = 0.53, p = 0.01) 2 V a l u e s f i t t e d f r o m r e g r e s s i o n e q u a t i o n : B r u i s e d f r u i t = 0.8 + 0.114 H e i g h t ( r = 0.68, p = 0.01) R e g r e s s i o n e q u a t i o n not s i g n i f i c a n t . F r u i t w i t h < 5 mm diam p i t t i n g = 14.0 (p > 0.01) 2 V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : F r u i t w i t h •> 5 mm diam p i t t i n g = -1.9 + 16.7 S u r f a c e + 0.587 H e i g h t (R = 0.94, p = 0.01) 2 2 V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : P i t t e d f r u i t = 6.3 + 23.2 S u r f a c e x h e i g h t - 0.00161 S u r f a c e x h e i g h t (R =•= 0.96, p = 0.01) T a b l e 31. E f f e c t s o f d e f o r m a t i o n , l o a d i n g r a t e and l o a d i n g s u r f a c e d i s o r d e r s i n 'Van' c h e r r i e s , 1978 c r o p . s u r f a c e on the i n c i d e n c e o f L o a d i n g s u r f a c e D e f o r m a t i o n (mm) L o a d i n g r a t e (mm/min) B r u i s e d f r u i t (%,) F r u i t w i t h s u r f a c e marks (%) F r u i t w i t h < 5 mm d i a m e t e r p i t t i n g (%) F r u i t w i t h > 5 mm d i a m e t e r p i t t i n g (%) P i t t e d f r u i t (%) .Loading s u r f a c e coded a s : Smooth = 0; Rough = 1 2 2 V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : B r u i s e d f r u i t = 0.800 + 0.803 D e f o r m a t i o n ( r = 0.92, p = 0.01) V a l u e s f i t t e d f r o m r e g r e s s i o n e q u a t i o n : F r u i t w i t h s u r f a c e marks = 5.5 + 0.00128 D e f o r m a t i o n x L o a d i n g s u r f a c e x L o a d i n g r a t e ( R 2 = 0.36, p = 0.01) V a l u e s f i t t e d f r o m r e g r e s s i o n e q u a t i o n : F r u i t w i t h £ 5 mm diam p i t t i n g = 5.5 - 5.65 B r u i s i n g s u r f a c e + 1.017 D e f o r m a t i o n x L o a d i n g s u r f a c e (R = 0.63, p = 0.01) V a l u e s f i t t e d "from r e g r e s s i o n e q u a t i o n : F r u i t w i t h > 5 mm diam p i t t i n g = -8.8 + 2.38 D e f o r m a t i o n + 0.00455 D e f o r m a t i o n x L o a d i n g r a t e (R = 0.84, p = 0.01) 2 V a l u e s f i t t e d f r o m r e g r e s s i o n e q u a t i o n : P i t t e d f r u i t = -7.0 + 3.11 D e f o r m a t i o n + 0.00411 D e f o r m a t i o n x L o a d i n g r a t e + 0.468 D e f o r m a t i o n x L o a d i n g s u r f a c e ( R 2 = 0.93, p - 0.01) T a b l e 32. E f f e c t s o f c h e r r y f r u i t w e i g h t and work done on f r u i t on t h e i n c i d e n c e o f s u r f a c e d i s o r d e r s , 1977 c r o p . F r u i t w e i g h t (8) Work done on f r u i t ( j o u l e s ) B r u i s e d f r u i t (%) F r u i t w i t h s u r f a c e marks .00 F r u i t w i t h < 5 mm d i a m e t e r p i t t i n g (%) F r u i t w i t h > 5 mm d i a m e t e r p i t t i n g (%) P i t t e d 0 0 f r u i t 7.11 0.050 1 3 . 8 y 1 8 . 4 X 2.2 v 94.3 95. ,8U ' 9.19 0.050 30.9 18.4 2.2 77.0 83. ,7 7.11 0.032 z 13.8 18.4 2.2 70.7 73. ,4 9.19 0.045* 30.9 18.4 2.2 72.1 77. ,5 Drop h e i g h t c o n s t a n t a t 0.45 m. V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : B r u i s e d f r u i t = -44.9 + 8.25 F r u i t w e i g h t ( r " = 0.70, p = 0.01). R e g r e s s i o n e q u a t i o n n o t s i g n i f i c a n t . F r u i t w i t h s u r f a c e marks = 18.4 (p > 0.01). R e g r e s s i o n e q u a t i o n n o t s i g n i f i c a n t . F r u i t w i t h < 5 mm diam p i t t i n g = 2.2 (p > 0.01) V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : F r u i t w i t h > 5 mm diam p i t t i n g = 28.7 + 2500 Work done - 167 F r u i t w e i g h t x Work done, (R2 = 0.85, p = 0.01) 2 V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : P i t t e d f r u i t - 75.0 + 1240 Work done - 5.80 F r u i t w e i g h t (R = 0.85, p - 0.01). T a b l e 33. E f f e c t s o f c h e r r y f r u i t w e i g h t and work done on f r u i t on t h e i n c i d e n c e o f s u r f a c e d i s o r d e r s , 1978 c r o p . F r u i t w i t h F r u i t w i t h F r u i t w e i g h t (8) Work done on f r u i t ( j o u l e s ) B r u i s e d f r u i t (%) F r u i t w i t h s u r f a c e marks (%) < 5 mm d i a m e t e r p i t t i n g (%) > 5 rem d i a m e t e r p i t t i n g (%) P i t t e d f r u i t (%) 5.70 0.04 y 5.2 1 3 . 0 X w 13.4 8 3 . 5V 5 1 . 2 U 7.20 0.04 5.2 13.0 13.4 53.9 23.2 5.70 0.025 2 5.2 13.0 13.4 68.1 57.7 7.20 0.034 2 5.2 13.0 13.4 45.8 22.4 Drop h e i g h t c o n s t a n t a t 0.45 m. R e g r e s s i o n e q u a t i o n not s i g n i f i c a n t . B r u i s e d f r u i t » 5.2 (p > 0.01) R e g r e s s i o n e q u a t i o n not s i g n i f i c a n t . F r u i t w i t h s u r f a c e markings •» 13.0 (p > 0.01) R e g r e s s i o n e q u a t i o n not s i g n i f i c a n t . F r u i t w i t h < 5 mm diam p i t t i n g = 13.4 (p > 0.01) 2 V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : F r u i t w i t h > 5 mm diam p i t t i n g = 162.0 - 21.0 F r u i t w e i g h t + 1030 Work (R = 0.93, p = 0.01) 2 V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : P i t t e d f r u i t - 196 - 24.7 F r u i t w e i g h t + 17.5 F r u i t w e i g h t x Work (R «= 0.87, p - 0.01) T a b l e 34. E f f e c t s o f f r u i t s i z e on mesocarp c o m p o s i t i o n of 'Van' c h e r r i e s on f r e s h w e i g h t b a s i s , 1978 c r o p . T o t a l Water s o l u b l e mesocarp Mesocarp Mesocarp Mesocarp Mesocarp F r u i t s i z e T o t a l p e c t i n p e c t i n AIS N Ca Mg K Zn (g) (%) (%) (%) (%) (mg/kg) (mg/kg) (mg/kg) (mg/kg) 6.52b z 0.524a 0.204a 2.202a 0.939a 26.8a 20.8a 261a 0.18a 7 . 9 9 a 0.504a 0.226a 2.181a 0.837b 22.5a 18.5a 244a 0.14a , z Mean s e p a r a t i o n w i t h i n a column by Student's-t t e s t , 5% l e v e l . T a b l e 35. E f f e c t s o f f r u i t s i z e on mesocarp c o m p o s i t i o n o f 'Van' c h e r r i e s on d r y w e i g h t b a s i s , 1978 c r o P . F r u i t Weight S o l u b l e s o l i d s (g) ™ T i t r a t a b l e a c i d i t y T o t a l p e c t i n (mgMalic/lOOml) (%) Water s o l u b l e p e c t i n C e l l u l o s e (%) (%) T o t a l mesocarp K (%) Mesocarp Ca (mg/kg) Mesocarp Mesoc^ ro Mesocarp M o K Zn (mg/kg) (*g/kg) (=g/kg) 6.52b 7.99a 13.0a 13.9a 807a 811a 24.4a 23.5a 9.29a 0.357a 6.26a 10.26a 0.398a 5.08b 1051a 924b 753a 10940a 7.0a 699b 10220b 6.2b f Mean s e p a r a t i o n w i t h i n a column by Student's-t t e s t , 5% l e v e l . T a b l e 36. E f f e c t of c h e r r y f r u i t w e i g h t and m a t u r i t y on s t o r a g e d i s o r d e r s , 1977 c r o p . M a t u r i t y F r u i t weight (g) F r u i t w i t h s u r f a c e marks (%) F r u i t w i t h b r u i s e s (%) F r u i t w i t h < 5 mm d i a m e t e r p i t t i n g (%) F r u i t w i t h > 5 mm d i a m e t e r p i t t i n g (%) F r u i t w i t h p i t t i n g (%) 3 6 33 3 6 33 6.21 7.04 8.08 8.04 9.04 10.50 17.9a' 42.4a 19.8a 18.8a 35.0a 19.8a 12.9d 13.8d 38.8b 31.8c 40.7b 53.5a 2.9a 2.5a 7.7a 1.5a 3.9a 8.5a 79.7a 78.5a 40. Od 60.8b 47.2c 17.8e 82.6a 81.0a 47. 7 d 62.3b 5 1 . i c 26.3e I z C o l o r c omparator q u a l i t a t i v e i n d i c e s o f m a t u r i t y . y Mean s e p a r a t i o n w i t h i n a column by Newman-Keuls t e s t , 5% l e v e l . T a b l e 37. E f f e c t s o f g i b b e r e l l i c a c i d and m o b i l e a f s p r a y s on c h e r r y f r u i t d i s o r d e r s , 1977 c r o p . Spray H a r v e s t F r u i t w i t h b r u i s e s (%) F r u i t w i t h s u r f a c e marks (%) F r u i t w i t h < 5 mm d i a m e t e r p i t t i n g (%) F r u i t w i t h > 5 mm d i a m e t e r p i t t i n g (%) F r u i t w i t h p i t t i n g (%) No s p r a y 20 ppm GA 20% M o b i l e a f 13.1c' 11.Ac 9.Ac 16.8b 19.8b 16.5b 12.9a 15. Aa 18.0a A2.3b 22.6c 52.2a 55.1b 38.1c 70.2a C3N I No s p r a y 20 ppm GA 20% M o b i l e a f A3, l a 28.6b 33.7ab 27.6b 27.9b AA.9a 5.5a 3.8a 6.9a 6.3d 5.6d 7.5d 11.9de 9.6de 14, Ad Mean s e p a r a t i o n , w i t h i n a column, Newman-Keuls t e s t , 5% l e v e l . T a b l e 38. E f f e c t s o f f r u i t m a t u r i t y and p r e h a r v e s t g i b b e r e l l i c a c i d s p r a y on t h e i n c i d e n c e of s u r f a c e d i s o r d e r s i n 'Van' c h e r r i e s , 1978 c r o p . M a t u r i t y G i b b e r e l l i c a c i d s p r a y B r u i s e d f r u i t (%) F r u i t w i t h s u r f a c e marks (%) F r u i t w i t h < 5 min d i a m e t e r p i t t i n g (%) F r u i t w i t h > 5 mm d i a m e t e r p i t t i n g (%) P i t t e d f r u i t (%) o z 0 9.4y • 12.1X 15.5W 52. 5V u 1 70.8 h 0 1 9.4 12.1 15.5 15.0 28.3 t: 1 0 9.4 12.1 15.5 7.5 22.5 1 1 9.4 12.1 4.5 1.0 7.5 z Coded f o r q u a l i t a t i v e i n d i c e s o f c o l o r m a t u r i t y : 0 = No. 3, 1 = No. 33. y R e g r e s s i o n e q u a t i o n n o t s i g n i f i c a n t . B r u i s e d f r u i t = 9.4 ( p > 0.01) > x R e g r e s s i o n e q u a t i o n n o t s i g n i f i c a n t . F r u i t w i t h s u r f a c e marks = 12.1 (p > 0.01) 2 w V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : F r u i t w i t h < 5 mm diam p i t t i n g = 15.5 - 9.0 M a t u r i t y x G i b b e r e l l i c s p r a y ( r = 0.61, p = 0.01) v V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : F r u i t w i t h > 5 mm diam p i t t i n g » 52.5 - 45.0 M a t u r i t y - 37.5 G i b b e r e l l i c s p r a y + 31.0 M a t u r i t y x g i b b e r e l l i c s p r a y ( R ' = 0.96, p = 0.01) u V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : P i t t e d f r u i t = 70.8 - 48.3 M a t u r i t y - 42.5 G i b b e r e l l i c s p r a y + 27.5 M a t u r i t y x g i b b e r e l l i c s p r a y (R ' = 0.96, p - 0.01) T a b l e 39. E f f e c t s of p r e h a r v e s t g i b b e r e l l i c a c i d s p r a y on 'Van' c h e r r y mesocarp c o m p o s i t i o n on a f r e s h w e i g h t b a s i s , 1978 c r o p . Treatment T o t a l p e c t i n (%) Water s o l u b l e p e c t i n (%) A l c o h o l i n s o l u b l e s o l i d s (%) T o t a l mesocarp N • (%) Dry ' Weight (%) Mesocarp Ca (mg/kg) Mesocarp Mg • . (mg/kg) Mesocarp Zn (mg/kg) Mesocarp K (mg/kg) Mesocarp Mn (mg/kg) No s p r a y O.509a Z 0.264a 1.807b 0.896a 16.5b 176a 126a 1.2a 1843a 0.72a 30 ppm GA 0.503a 0.326a 2.044a 0.741b 18.0 a 183a 132a 1.3a 1812a 0.78a z Mean s e p a r a t i o n w i t h i n columns by Student"s-t t e s t , 5% l e v e l . T a b l e 40. E f f e c t s o f p r e h a r v e s t g i b b e r e l l i c a c i d s p r a y on 'Van' c h e r r y mesocarp c o m p o s i t i o n on a d r y weight b a s i s , 1978 c r o p . Water s o l u b l e Treatment T o t a l p e c t i n p e c t i n C e l l u l o s e (%) (%) < « T o t a l mesocarp N (%) Mesocarp Ca (mg/kg) Mesocarp Mesocarp Mesocarp Mesocarp Mg Zn X Mn ' (mg/kg) (mg/kg) (mg/kg) (mg/kg) vO I No s p r a y 30 ppm GA 27.8a' 25.1a 14.4a 0.553a 16.6a 0.526a 5.43a 4.36b 982a 1043a 742a 727a 7.1a 7.1a 11170a 10660b 4.4a 3.8a z Mean s e p a r a t i o n w i t h i n columns by S t u d e n f s - t t e s t , 5% l e v e l . T a b l e 41. E f f e c t s o f f r u i t t h i n n i n g on s o l u b l e s o l i d s , t i t r a t a b l e a c i d i t y , f r u i t w e i g h t and t e x t u r e o f 'Van' c h e r r y f r u i t , 1977 c r o p . O r c h a r d F r u i t t h i n n e d S o l u b l e s o l i d s (%) T i t r a t a b l e a c i d i t y (mgMalic/lOOml) A l c o h o l i n s o l u b l e s o l i d s (%) F r u i t w e i g h t (g) B i o y i e l d (kg) F r u i t F i r m n e s s (kg/cm) 0 0 17.6 Z 9 0 9y 1.912 x w 8.08 1.764v 2.878 U 0 1 17.6 909 1.912 8.08 1.764 2.878 1 0 17.6 909 1.912 8.08 1.764 2.878 1 1 17.6 909 2.350 9.24 1.764 2.878 N 3 O R e g r e s s i o n e q u a t i o n n o t s i g n i f i c a n t . S o l u b l e s o l i d s = 17.6 (p > 0.01) R e g r e s s i o n e q u a t i o n n o t s i g n i f i c a n t . T i t r a t a b l e a c i d i t y = 909 (p > 0.01) 2 V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : AIS = 1.912 + 0.438 O r c h a r d x t h i n n e d ( r = 0.56, p - 0.01) 2 V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : F r u i t w e i g h t - 8.08 + 1.16 Or c h a r d x t h i n n e d ( r = 0.45, p = 0.01) R e g r e s s i o n e q u a t i o n n o t s i g n i f i c a n t . B i o y i e l d = 1.764 (p > 0.01) R e g r e s s i o n e q u a t i o n n o t s i g n i f i c a n t . F r u i t f i r m n e s s » 2.878 (p > 0.01) T a b l e 42. E f f e c t s o f f r u i t t h i n n i n g on t h e i n c i d e n c e o f s u r f a c e d i s o r d e r s i n 'Van' c h e r r i e s , 1977 c r o p . O r c h a r d F r u i t t h i n n e d B r u i s e d f r u i t <%) F r u i t w i t h s u r f a c e marks (%) F r u i t w i t h < 5 mm d i a m e t e r p i t t i n g (%) F r u i t w i t h > 5 inn d i a m e t e r p i t t i n g (%) P i t t e d f r u i t (%) 20.0 20.0 20.0 20.0 26.0' 26.0 26.0 17.7 13.9" 13.9 13.9 13.9 42.7 23.7 42.7 23.7 59.9 39.4 59.9 39.4 z R e g r e s s i o n e q u a t i o n n o t s i g n i f i c a n t . ' B r u i s e d f r u i t = 20.0 (p > 0.01) 2 y V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : F r u i t w i t h s u r f a c e m a r k i ngs = 26.0 - 8.28 O r c h a r d x t h i n n e d ( r = 0.39, p = 0.01) x R e g r e s s i o n e q u a t i o n n o t s i g n i f i c a n t . F r u i t w i t h < 5 mm diam p i t t i n g = 13.9 (p > 0.01) w V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : F r u i t w i t h > 5 mm diam p i t t i n g = 42.7 - 19.0 T h i n n e d ( r 2 = 0.49, p = 0.01) 2 v V a l u e s f i t t e d from r e g r e s s i o n e q u a t i o n : P i t t e d f r u i t - 59.9 - 20.5 T h i n n e d ( r = 0.51, p - 0.01) - 122 -Fig. 1. Typical surface pitting and surface markings in 'Van' cherry. Fig. 2. Radial section of 'Van' cherry (slight injury), showing surface pitting and injured zone in the lower hypodermal cells (from reference 70). - 123 -Fig. 3. Effect of cherry production on estimated susceptibility to pitting. - 124 -Fig. 4. Probe attachment to Ottawa Texture Measuring System. D e f o r m a t i o n t o b i o y i e l d ( cm) D e f o r m a t i o n ( c m ) B - F o r c e a t b i o y i e l d ( k g ) C — F r u i t f i r m n e s s ( s l o p e o f l i n e a r p o r t i o n o f c u r v e (k g/c m) Fig. 5. Typical force-deformation curve of individual cherry pressure test. Fig. 6. Moisture loss of sweet cherry flesh stored at 65 C. Fig. 7. Calcium-45 Quench Correction Curve. S L I T W I D T H Fig. 8. Carbon-14 Energy Spectrum. 700 600 CL v O / S O O f UJ r-3 Z 400f CC u i CL (ft r -Z 3 o o 300h 200 100 100 200 300 . S L I T W I D T H 400 500 600 Fig. 9. Calcium-45 Energy Spectrum. 10.0 g 0.4 0.5 0.6 0.7 0.8 D I S T A N C E O F F R E E F A L L (rn) Fig. 10. Work done on cherry versus distance of free f a l l and frui t weight, I 2 0 0 r 6 0 0 0 Log (Calcium) = 2.920 - 0.003430 Day + 0.1536 Log (Day) 2 (R = 0.94, p = 0.01) Mesocarp calcium of undipped control = 545 ppm ^  14 6 8 10 12 S T O R A G E T I jME ( D a y s ) 16 18 2 0 2 2 Fig- 11. Calcium uptake by 'Van' cherry. - zti -Fig. 13. Calcium uptake by cherries from postharvest calcium chloride dips modified by thickener. Ui JX 0 » E 400 U J 350 < 1 -Q . 300 3 E 250 3 U _ j 200 < u 150 cc < 100 u o V) 50 U J s 0 Mesocarp calcium - -22.6 + 50.8 Day - 6.37 Surf x Day + 37.1 Log (Day) x Thickener - 28.2 Log (Day) x Day + 8.77 Log (Day) x Surf x Thickener (R2 = 0.86, p = 0.01) 2.5g/| thickener 1.0 hnl/l surfactant 2.5g/| thickener 0.0 'ml/l surfactant thickener Q.Qmy\ surfactant 0.0 g/| thickener LOmly'l surfactant 4 6 8 10 12 S T O R A G E T I M E ( D a y s ) 14 16 4> Figure 14. Mesocarp calcium uptake by 'Van' cherries from a postharvest dip modified by surfactant and thickener. 1300 Mesocarp calcium = 2.8896 + 0.0003204 Time w + 0.07688 Thickener , + 0.03250 Log (Time). (R 2 = 0.77, p = 0.01) • N o t h i c k e n e r • 2 .5 g t h i c k e n e x / x 60 9 0 120 150. 180 210 2 4 0 T I M E I N D I P ( m in ) Effect of calcium chloride postharvest dip on flesh calcium uptake in 'Van' cherry. Fig. 15. 2.001 Bioyield = 0.428 + 0.00065 Mesocarp calcium. (r = 0.86 , p 1.50 U l I OQ 1.00 0.50 to as 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 M E S O C A R P C A L C I U M { m g / k g ] Fig. 16. Mesocarp calcium versus bioyield in 'Van' cherries. 4 . 5 0 r 4 . 0 0 £ 3.50 (0 3 . 0 0 CC LL z W 2.50 U J 2 . 0 0 1.50 Firmness = 0.877 + 0.0015 Mesocarp calcium ( r 2 = 0.88, p = 0.01) 1.00 400 600 800 1000 1200 1400 1600 1 8 0 0 2000 M E S O C A R P C A L C I U M ( m g / k g ) Fig. 17. Mesocarp ca lcium versus fruit firmness in 'Van' cherries. - 138 -Fig. 19. Micrograph of No. 3 color maturity cherry tissue immediately after impact (x60). Fig. 21. Micrograph of non-damaged No. 33 color maturity cherry tissue (x750). - 140 -Fig. 22. Micrograph of No. 33 color maturity cherry tissue immediately after impact (x750). Fig. 23. Micrograph of No. 33 color maturity cherry tissue showing damage 9 days after impact (x750). 7.0 P STORAGE TIME (Days) Fig. 24. Weight loss in 'Van' cherries due to relative humidity in storage (n = 4). 

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