POLLEN PARENT EFFECT ON THE SELECTIVE ABSCISSION OF MAURITIUS AND FLORIDIAN LYCHEE FRUITLETS

Fruit produced by adjacent blocks of 'Mauritius' and 'Floridian' lychee (Litchi chinensis Sonn.) were sampled at four different stages of development and the embryos were analyzed for pollen parentage by phosphoglucose isomerase (PGI; EC 5.3.1.9) isozyme system. Hybrid percentage increased significantly from approximate to 5 weeks after fruit set to maturity as follows: from 29.5% to 76.3% in 'Mauritius' and from 74.2% to 92.5% in 'Floridian'. These findings clearly indicate selective abscission of selfed fruitlets. In 'Mauritius', yield was not related to the distance from the pollenizer block or hybrid percentage. In 'Floridian', yield of trees adjacent to the 'Mauritius' pollenizer was higher by 36% than that of trees at a distance of 24 m. The correlation between 'Flordian' yield and hybrid percentage tended toward significance (r = 0.64, P = 0.08). In addition, in both cultivars, fruit and seed weights were affected by the pollen parent: outcrossed fruit were heavier and contained heavier seeds than selfed ones.