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- Author or Editor: Elias D. Dekazos x
Postharvest ripening treatments (ethephon, fungicides, and/or storage conditions) of green, ‘Babygold 7’ peaches [Prunus persica (L.) Batsch] accelerated ripening and color development, and produced fruit of high quality as measured by various quality parameters. Peaches thus treated contained a higher level of carotenoids than tree-ripened fruit, and were practically decay free. Lycopene accumulation was stimulated in tissue treated with CPTA. Peaches held at 41°C and 90% ± 1% RH for 24 hr before dipping in 250 ethephon for 1 min, and ripening at 27° and 90% ± 1% RH, produced one of the most efficient methods of fruit ripening. Chemical names used: (2-chloroethyl)phosphonic acid (ethephon); 2-(4-chlorophenylthio)-triethylamine hydrochloride (CPTA).
Sprays of aminoethoxyvinylglycine (AVG) to intact branches of ‘Rio Oso Gem’ and ‘Loring’ peaches [Prunus persica (L.) Batsch] after completion of the rest period effectively delayed blossoming by about 10 days. AVG (5,000 and 10,000 ppm) did not reduce flowering, fruit set or fruit quality. At high concentration, AVG prevented most of the terminal buds from growing normally; the terminal shoots were short, with dense foliage. Lateral buds had a normal linear shoot growth. Foliar injury was slight. The fruit weight of treated ‘Loring’ peaches was reduced by 11.5% but color attributes, particularly flesh color, were not influenced by AVG. Bloom delay did not affect firmness, soluble solids and titratable acidity in ‘Loring’ but did increase firmness and soluble solids slightly and decrease titratable acidity in ‘Rio Oso Gem’. Overall fruit size, color, soluble solids, titratable acidity and firmness tests indicated that AVG did not delay maturity.
Light transmittance curves of intact blueberries, ‘Wolcott’ and ‘Bluecrop’ cul-tivars, were recorded in the visible and infrared with the ASCO Biospect and correlated with anthocyanin content. Correlation coefficients were computed for a large number of possible maturity indexes to determine the optimum index. In all cases the index involves the measurement of the optical density of the intact fruit at 2 wavelengths and computation of the optical density difference. From the ‘Wolcott’ blueberry correlation data, the highest correlations, 0.925 and 0.967, were found in the infrared region between ∆OD(760–800 nm) vs anthocyanin content per berry and between ∆OD(760–800 nm) vs anthocyanin content per g fresh weight of tissue, respectively. For the ‘Bluecrop’ blueberry, the highest correlations, 0.933 and 0.916, were found in the infrared region between ∆OD(740–800 nm) vs anthocyanin content per berry and between ∆OD(740–800 nm) vs anthocyanin content per g fresh weight of tissue, respectively. Thus, optical density difference measurements of individual intact fruits afford a reliable maturity index for blueberries.
Red tart cherries treated with succinic acid 2,2-dimethyl hydrazide (Alar) were studied for changes in anthocyanin pigments and also histochemical changes. Anthocyanin biosynthesis was altered as a result of the treatment. The significant effect of Alar was to change markedly most of the individual pigment ratios. Of note is the fact that the concentration of the pigment peonidin 3-rutinoside was unaltered. The treated fruit showed an increase in total anthocyanin pigment.
Alar treatment also caused both quantitative and qualitative changes in cell wall carbohydrate composition. Treated fruit had more total wall material and showed callose formation. Furthermore, the sprayed fruit contained more pectin and hemicellulose. The amount of cellulose and lignin was not affected. The relation between changes in cell wall polysaccharides and increased firmness of sour cherries as a result of the treatment is discussed.