of maturity can lead to bitter pit, whereas harvest at later stages can lead to chilling injury (CI) during storage in ‘Honeycrisp’ ( Watkins et al., 2005 ). Harvest of ‘McIntosh’ at an early stage can lead to core browning and at advanced maturity to
inhibits necessary cell signaling ( Gilliham et al., 2011 ; Ho and White, 2005 ). Bitter pit is among these Ca-related disorders and renders 5% to 10% of harvested apples unmarketable each year. In ‘Honeycrisp’ apple, it is not uncommon to lose up to 50
Abstract
Calcium concentration of ‘Golden Delicious’ (Malus × domestica Borkh.) apples was reduced with a single, early application of 50 ppm TIBA. Early, midseason, and late sequences of 3 sprays of CaCl2 (3.6 g/1) were applied to evaluate timing effectiveness for increasing fruit Ca concentration and decreasing fruit pitting. Mid-June, July, and August sprays increased fruit Ca concentration less than later sprays, but more effectively reduced fruit pitting. Chemical name used: 2,3,5-triiodobenzoic acid (TIBA).
Abstract
‘Delicious’, ‘Golden Delicious’, and ‘Stayman’ apple trees (Malus domestica Borkh.) were summer pruned in late June or mid-August. Fruit were smaller on June- or August-pruned ‘Stayman’ trees than on comparable dormant-pruned control trees. Summer pruning had little effect on the size of ‘Delicious’ and ‘Golden Delicious’ fruit. Soluble solids were suppressed within 2 weeks after summer pruning on all cultivars, but fruit firmness was unaffected. Summer pruning slowed the rate of starch disappearance from fruit flesh. Preharvest drop, severity of watercore, and bitter bit were suppressed by summer pruning. Calcium concentration of fruit flesh was not significantly increased by summer pruning. Yield, expressed as total fruit weight or number of fruit per tree, was not consistently influenced by summer pruning over a 2-year period.
Abstract
‘Nittany’ is a ‘York Imperial’-type apple possessing outstanding processing characteristics. Fruit from the original seedling tree has been essentially free of corking; mild corking has been observed in some large fruits from propagules on size-controlling rootstocks. The fruit can be held in refrigerated storage for at least 6 months without appreciable shrinkage or loss of quality. The flesh oxidizes very slowly when exposed to the air and imparts a highly desirable yellow color to processed products.
Abstract
‘Golden Delicious’ apple trees sprayed with 50 ppm 2,3,5-triiodobenzoic acid (TIBA) 28 days after bloom had pitted fruit at harvest, but comparable control trees had none. The appearance of the pits on the fruit was similar to bitter pit. TIBA decreased the fruit Ca content and increased fruit B content. Decrease in Ca content by TIBA probably caused the development of bitter pit on the fruit.
end point with data expressed as g/100 mL malic acid equivalents. An additional random subsample of 10 fruit at harvest was used to calculate incidence of disorders including water core, sunburn, internal breakdown, and bitter pit. Analysis of variance
Abstract
Calcium (Ca) level of leaves sampled in mid- or late summer was closely related to peel Ca levels of mature apples (Malus pumila Mill. cv. Baldwin). Ca content of fruit was directly related to fruit yield of the tree, cycling with biennial bearing. In 1971 bitter pit incidence could be predicted from either leaf or peel Ca; internal breakdown and decay were less predictable. In 1972 leaf Ca and peel Ca averaged, respectively, 27 and 17% higher than in 1971, accompanying increased yield. Little bitter pit, internal breakdown, or decay occurred, even at Ca levels correlated with high incidence rates the previous year. We concluded that Ca must be only 1 among several factors regulating these occurrences.
Abstract
There is considerable confusion in the literature on the terminology of internal storage disorders of apples. For example, “internal breakdown” is a term widely used to cover all such problems. The focus here is on breakdown problems and excludes physiological disorders like bitter pit. The emphasis is on symptomology, factors associated with the disorders, and cultivar susceptibility. There is little or no mention of control measures.
Sprays of calcium materials were applied at high volume rates (620 g Ca/400 liters) with a handgun during early June, late June, and mid-July versus mid-July, early August, and late August for five years, 1985 to 1989. Leaf injury was most severe for the late sprays but no spray injury was observed on the fruit surfaces. Bitter pit was markedly reduced with all sprays except CaSO4. In some years, bitter pit was controlled better with the early sprays. Either early or late sprays improved fruit quality including overall appearance, reduced scald development, improved red color of the skin, increased fruit firmness and reduced incidence of bitter pit in cold air (0°C) storage. Soluble solids and acidity in the fruit was not affected by calcium sprays. Leaf Ca was higher from the late spray applications than from the earlier applications. All calcium chloride spray materials resulted in increased fruit peel and cortex Ca. Calcium nitrate sprays tended to increase fruit nitrogen concentrations leading to undesirable higher N:Ca ratios in the fruit.