Produção de frutos de alta qualidade e sem sementes com o uso do GA3 em atemoieira

Abstract

Atemoya culture has been gaining space in the market due to the excellent organoleptic quality and added value of the fruit. In the management of production of this fruit tree, the use of growth regulators, in particular the gibberellins, has allowed for the production of excellent commercial standard fruits with and without seeds. This study aimed to evaluate the effect of gibberellic acid (GA3), applied in different dose levels and times, on fruit set and quality for 'Gefner' atemoya. Two experiments were carried out in a randomized complete block design with four replicates, and the treatments were submitted to different dose levels of GA, associated or not with artificial pollination. The first experiment was treated with the following GA doses: 250, 500 and 1,000 mg L associated or not with artificial pollination. The second experiment was treated with the following GA3 doses: 100, 150, 200, 250, 500 and 1,000 mg L¹ associated or not with artificial pollination. Fruit set, length and diameter were evaluated every seven days, and the physical-chemical characteristics were evaluated after harvest. In the first experiment, 'Gefner' atemoya fruit length and diameter, regardless of the treatments applied, followed a sigmoidal growth pattern, with a slow first stage until the3d week after anthesis (WAA). The second stage presented more accelerated growth up to the 8th WAA, followed by slower growth at the final stage until harvest in the 17th WAA. Artificial pollination combined with two GA, doses of 250 mg L' yielded grown 'Gefner' atemoya fruits, with a high pulp percentage and excellent physical-chemical characteristics. Application of GA, dose of 1,000 mg L¹, divided into four doses, without artificial pollination, provided high percentage of seedless fruit set with excellent physical-chemical quality. In the second experiment, the growth rate of fruit length and diameter presented a sigmoidal pattern in all treatments, with the highest peak in the 4th and 5th WAA. Artificial pollination, associated to two GA, doses of 250 mg L, in the 2nd and 4th WAA, presented high fruit set and high proportions of fruit length, diameter and mass as well as a reduced total seed fresh mass. The application of GA; dose of 1,000 mg L", divided into four doses as of anthesis, yielded seedless fruits with physical and physical-chemical properties equivalent to to those of fruits that received artificial pollination. Isolated application of GA, yielded fruits with pulp percentage higher than that of artificially pollinated fruits.