Flowering and fruit set in cherimoya (Annona cherimola Mill.) as affected by the tree-training system

Abstract

SummaryManagement of flowering and fruit set are of prime importance in order to obtain high yields in cherimoya (Annona cherimola Mill.) due to floral dichogamy. This phenomenon is largely dependent on environmental conditions such as temperature, relative humidity, and light intensity, which usually make hand-pollination of flowers necessary in order to achieve acceptable levels of fruit set and yield. Nevertheless, these factors can be modified by means of the growing system. In this work, we studied the effects of two tree-training systems on the environment inside the canopy, on flowering, on pollination, and on fruit set in mature ‘Concha Lisa’ cherimoya trees. The open-centre vase training system (6 m 4 m) and the high-density slender-spindle (tunnel) training system (4 m 1 m) were used. The high-density tunnel training system increased the relative humidity, as well as reducing the temperature and the level of photosynthetically active radiation, inside the canopy, which resulted in an earlier onset of the male floral stage and in an extended maintenance of the highly-receptive female stages. This resulted in an overlap of the sexuallycompatible floral stages, thus increasing the incidence of natural cross-pollination and maintaining the viable, receptive sexual stages and pollen, over time, to improve hand-pollination.