The influence of the product Obsthormon 24a, on the quality index of the fruits of the Gala Must variety

Abstract

The research was carried out with the apple fruits of the variety "Gala Must" grown on the M9. To determine the effectiveness of the product Obsthormon 24a (NAA) on the degree of fruit ripening and quality indices, five different treatment doses and frequencies were studied in the pre-harvest period. In apples from the crown of the tree and fallen to the ground, the firmness of the

pulp was studied with penetrometer FT 327, the soluble dry substance with the refractometer and titratable acidity by the titration method with subsequent calculation in malic acid. Lower pulp firmness values were recorded in the control variant (8.3 kg/cm2), compared to the variants treated with the product Obsthormon 24a (ANA) (7.8-8.1 kg/cm2), the difference being

0. 3-0.5 kg/cm2. A lower fruit firmness was recorded in the NAA variant 37.5 ppm (7.8 kg/cm2) compared to the other treated variants (8.0-8.1 kg/cm2). The higher amount of dry substance in the fruits was recorded in the variants NAA 30 ppm and NAA 37.5 ppm (14.6%) while in the other variants, the studied index was identical, or slightly higher than in the variant control. The titratable acidity of the fruits of the Gala Must variety varied between 0.26 and 0.30%. This legitimacy is also found in the case of fruits that have fallen on the ground, only the values obtained are much higher than the previous ones, constituting 0.24-0.26%. Increasing the dose of ANA treatment led to a more intense ripening of the fruit, a decrease in firmness and titratable acidity, as well as an increase in dry substance. To prevent premature fruit drop, and maintain a favorable relationship between fruit ripening and quality indicators, the first treatment with the product Obsthormon 24a in a dose of 15 ppm to be applied in the first decade of July, when the differentiation of the fruit buds begins, and the next with the same concentration 15 days before harvesting.