Role of natural self-pollination in self-fruitfulness of almond

Abstract

The capacity for self-fruitfulness in the almond cultivar 'Le Grand' is limited by (a) self-incompatibility and (b) insufficient capacity for natural self-pollination. Expression of self-incompatibility following self-pollination by hand reduced fruit-set by 67 and 89% in 2 crop-years in comparison with fruit-set percentages achieved following cross-pollination by hand. Pollen retention following natural self-pollination equalled about 8 pollen grains/stigma and reduced fruit set by 50% when compared with branches receiving non-limiting (> 300 grains) quantities of self-pollen. These data indicate that 'Le Grand' is (a) unsuited for planting in monoculture and (b) highly dependent on insect-mediated pollen transfer. Blossom observations made at anthesis indicated that the relative capacity for natural self-pollination among clones may be anticipated by the spatial relationship between dehiscing anthers and receptive stigmas. © 1985.