Fruit set in lychee (Litchi chinensis Sonn.). Variation between flowers, panicles and trees

Abstract

The ability of lychee cv. Bengal (Litchi chinensis Sonn.) female flowers to produce fruit has been investigated within individual panicles. Female flowers were pollinated with pollen from the same cultivar or removed manually. These experiments showed that 13.3% of the flowers opening on the first three days of the female phase of anthesis produced fruit. This was significantly fewer than the 22.8% of female flowers opening 4 to 6 days after commencement of female anthesis. Only 9.2% of flowers produced fruit on panicles in which every female flower was pollinated and none removed. No panicle yielded more than 28 fruit. The variation in female flower fecundity within a panicle, and the decrease in the proportion of flowers that yielded fruit as the number of flowers pollinated per panicle increased imply that comparisons between different treatments to lychee flowers should be made on entire panicles and not individual flowers. There was no difference between replicates of treatments on the same tree nor in the performance of individual trees. The time of day that pollination was performed appeared to have little effect on the percentage of fruit retained. There was no obvious relationship between prevailing weather conditions on the day of pollination and fruit production.