GENETIC DIVERSITY IN LITCHI AND LONGAN GERMPLASM AS DETERMINED BY SRAP MARKERS

Sequence-related Amplified Polymorphism (SRAP) was used to analyze the genetic diversity of 32 accessions of litchi and longan germplasm from Guangdong, Guangxi, Fujian and Hainan Provinces of China. These accessions contained 28 litchi (Litchi chinensis Sonn.), 2 artificial intergeneric hybrids (litchi×longan), 1 longli (Dimocarpus confinis How et Ho) and 1 longan cultivar (Dimocarpus longana Lour. ‘Shi Xia’). Nine of the 60 screened pairs of primer produced efficient amplifications, which generated 339 loci with a polymorphic rate of 99.7% and average 37.7 loci per primer pair. Cluster analysis indicated that the similarity coefficients ranged from 0.481 to 0.993, suggesting a high genetic diversity among the tested accessions. The similarity coefficients of litchi germplasm ranged from 0.536 to 0.993, indicating a relatively high genetic diversity among most litchi germplasm, while the other few displayed close relationships. According to the dendrogram, the 32 accessions could be classified into five groups at 0.72 similarity coefficient. The first group involved 11 litchi cultivars/strains with early season and early-to-mid season, including ‘YA1’, ‘YN5’, ‘San Yue Hong’, ‘Fei Zi Xiao’, etc. The second group involved 16 litchi cultivars/strains with late season and extremely late season, including ‘Gui Wei’, ‘Wu He Li’, ‘Ma Gui Li’, etc. The third group included two artificial intergeneric hybrids and their female parent ‘Zi Niang Xi’. The fourth group only contained ‘Long Li’, a tentative natural hybrid of the longan and litchi genus. The fifth group was ‘Shi Xia’ Longan. This classification was consistent with fruit maturation period.