The effect of different concentrations of pre-harvest gibberellic acid on the quality and durability of ‘Obilnaja’ and ‘Black Star’ plum varieties

Abstract The research work aimed at investigating the effect of pre-harvest gibberellic acid (GA3) treatment on the quality of ‘Obilnaja’ and ‘Black Star’ Japanese plum varieties. GA3 was sprayed onto the trees during the fruit color break at 0, 25, 50, 75, and 100 ppm concentrations. After pre-cooling, the plums were placed in modified atmosphere packages and exposed to the following conditions as follows: short storage-transportation (ST) [20 days at 2 °C and 90% relative humidity (RH)]; distribution center (DC) (5 days at 6 °C and 80% RH), and shelf life conditions (SL) (2 days at 20 °C and 70% RH). Pre-harvest GA3 treatments increased the fruit weight and size. Treatment of GA3 at 50, 75, and 100 ppm increased the fruit flesh firmness and total soluble substances (TSS) values in both the plum varieties during storage, transport, and marketing; it also limited the weight loss during the marketing process. Treatment of GA3 had no significant effects on the color, titratable acidity (TA), and the total phenolic and antioxidant activity values of plums. Pre-harvest GA3 treatment at 50 ppm GA3 can be thus recommended for both the plum varieties due to its effect on the fruit quality.

Physiological maturity of seeds and colorimetry of fruits of Jatropha curcas L.

The objective was to relate the coloration of fruits of Jatropha curcas L during the maturation process with morphometric (fruits and seeds) and germinative characteristics (seeds). Fruits were collected at various maturation stages from mast trees located in Eldorado/MS, and six maturation stages were visually classified based on fruit's epicarp color. Epicarp digital colorimetry was used to characterize maturation stages in addition to morphometric variables of length and width of fruits and seeds, as well their water content. For determining the physiological potential it was used germination test, emergence velocity index and first count of germination. Results indicated that seeds of J. curcas should be harvested when fruit epicarp shows a reading equal or smaller than 82, 70 or 65 nm of red, green or blue scales from a digital color analyzer. Seeds of fruits with that colorimetry can be harvested in virtue of the maxim acumululation of dry mass, water content below 38,5% and higher physiological potential.