Ca. Mcconchie et al., INTERGENERIC HYBRIDIZATION BETWEEN LITCHI (LITCHI-CHINENSIS SONN) ANDLONGAN (DIMOCARPUS-LONGAN LOUR), Annals of botany, 74(2), 1994, pp. 111-118
The breeding barriers between commercial litchi (Litchi chinensis Sonn
.) and longan (Dimocarpus longan Lour.) cultivars were investigated by
conducting reciprocal pollinations. This work has shown that it is po
ssible to generate intergeneric hybrids using litchi as the female par
ent. Investigation of comparative in vivo pollen tube growth demonstra
ted that there is discrimination against cross- compared to self-polle
n at all sites in the pistil. Pollen tubes were frequently observed in
the ovary after cross-pollination in litchi but rarely in longan. Fru
it production was reduced after crossing in both longan and litchi. Is
ozyme analysis using phosphoglucose isomerase revealed that hybrid pro
geny only developed when litchi was the maternal parent. Morphological
ly the hybrid plants were similar to the maternal parent but leaves we
re smaller. Three types of seeds developed in litchi following pollina
tion with longan pollen. These were (1) normal seeds with a developed
testa and embryo, (2) seeds with aborted embryos but normal testa deve
lopment, and (3) seedless fruit where the ovule remained the same size
as at anthesis without further development of embryo or testa. The po
tential germplasm available to improve these crops within the Sapindac
eae is discussed.