RIPENING DELAY AND FRUIT DROP CONTROL IN ´IMPERIAL GALA´ AND ´SUPREMA´ (´FUJI´ SPORT) APPLES BY APPLYING AVG (AMINOETHOXYVINYLGLYCINE)
Gala and Fuji represent more than 90% of the one million tonnes of Brazilian apples produced in 2004. Many orchards are larger than 50 ha, which results in many apples being picked at an inadequate ripening stage. This is especially true for Gala, because it ripens rapidly during commercial harvest time, and it is susceptible to pre harvest fruit drop. Experiments with Gala and Fuji were carried out in Fraiburgo (27º Latitude S), Santa Catarina State Brazil, to evaluate the effect of the ethylene biosynthesis inhibitor Aminoethoxyvinylglycine (AVG) on pre harvest fruit drop and harvesting delay. The 6 treatments were distributed in a completely randomized block design, with 10 replicates of one tree per plot. The treatments were: 1 control (no AVG); 2 AVG 124 g ha-1 applied 4 WBHT (Weeks Before Harvest Time); 3 AVG 62 g ha-1 applied 4 WBHT + AVG 62 g ha-1 applied 2 WBHT; 4 - AVG 90 g ha-1 applied 2 WBHT; 5 - AVG 124 g ha-1 applied 1 WBHT; and 6 - AVG 90 g ha-1 applied 1 WBHT. The evaluations performed were percentage of fruit drop, harvest evolution, fruit color, fruit firmness, TSS, iodine-starch index, and fruit weight. AVG significantly delayed fruit ripening and reduced pre harvest fruit drop for Gala apple. The beginning of the harvest was delayed 10 days, and the end happened 16 days later than in the check plots. The fruit drop control was effective up to 40 days after applying AVG. The more effective treatments in promoting harvest delay and fruit drop control were those applied closer to the harvest time, independently of the AVG concentration used. AVG increased fruit weight, and delayed the development of the fruit red color. The AVG had little effect on delaying Fuji fruit ripening, but significantly reduced its water core incidence.
Petri, J.L., Leite, G.B., Argenta, L.C. and Basso, C. (2006). RIPENING DELAY AND FRUIT DROP CONTROL IN ´IMPERIAL GALA´ AND ´SUPREMA´ (´FUJI´ SPORT) APPLES BY APPLYING AVG (AMINOETHOXYVINYLGLYCINE). Acta Hortic. 727, 519-526
Malus domestica, harvest management, bioregulators, growth regulators, fruit firmness, water core