Pollen tube growth and genotype compatibility in cashew in relation to yield

Abstract

Hand pollination experiments were conducted with seedling trees of cashew to determine the period of pistil receptivity to pollen, the timing of pollen tube growth, and compatibility between genotypes. The results were assessed by fluorescence microscopy of the pollen tubes, and by yield measurements. The pistil supported maximum pollen germination and tube growth when pollinated within 3 h of anthesis, and penetration of ovules by pollen tubes was significantly reduced following pollination later than 3 h after anthesis. Pollen tube growth in the style was rapid, with pollen tubes reaching the base of the style by 3 h after pollination, but penetration of the ovules was delayed until between six and 24 h. Specific combining ability was detected amongst cashew genotypes as measured by pollen tube growth, and both specific combining ability and general combining ability as measured by final fruit set. No difference in pollen germination and tube growth between self and cross pollination was measured in any...