Effects of gibberellic acid and pollination on fruit set and fruit quality in 'Rocha' pear.

摘要

Most pear cultivars are self-incompatible and fruit production depends on cross-pollination, however complete or partially self fertile cultivars occur. In this case, as it is with the Portuguese 'Rocha' pear, fruit set is induced by gibberellic acid (GA) applications despite some adverse effects as abnormal fruit shape and poorer quality of seedless fruits. Field experiments of 'Rocha' spraying with GA at 10 ppm at 50% full bloom and 'Rocha' hand cross pollinated with a compatible cultivar 'Carapinheira' were set during two growing seasons to compare fruit set and fruit quality. Fruit drop was more precocious and severe when flowers were sprayed with gibberellic acid than when cross-pollinated with the compatible cultivar, at 40 DAFB the percentages of fruit drop were 89.1% and 66.3%, respectively. In the cross pollinated experiment, final fruit number was 3.5 fold superior than in the GA treated experiment, the ratio fruit diameter/length was 0.925 in seeded fruits and the fruits had in average 8 seeds. Fruits from the GA treated trees had 0.3 seeds and a fruit diameter/length of 0.775. At harvest, seed number did not affect any other quality characteristics of the fruit as TSS or firmness. Fruit quality characteristics after storage are currently under evaluation.