Optimal crop load and positioning of fruit in cherimoya ( Annona cherimola Mill.) trees

Abstract

Dichogamy and the lack of efficient pollinators in most producing countries make hand pollination of cherimoya unavoidable. In contrast to its high-cost, this technique allows growers to fix crop load levels and fruit location within the tree canopy. Over three consecutive years we have studied the optimal fruit load for the cultivar ‘Fino de Jete’ and checked the effects of the vigor of the fruit-bearing shoots and of the fruit position along the shoot on the resulting fruit set and quality. Our results show that yield in well-managed orchards fitted a logarithmic curve with a maximum close to 30 t ha −1 achieved by setting about 400 fruits per adult tree. No significant effects of crop load were detected on fruit size during the first 2 years; in the third year, however, trees with a lower yield produced heavier fruits. An upper limit of 0.22 kg (fresh fruit weight) cm −2 of trunk cross-sectional area is proposed if fruit quality is to be preserved. High yield during three consecutive years did not diminish tree growth. We found no consistent effects of shoot vigor on fruit set and quality. However, a gradient for heavier fruits was observed from the base to the apex of the bearing shoots.