Abstract:

Sonneratia alba J.Smith is a widely distributed mangrove species. Leaf samples of one hundred individuals from four natural and one introduced populations in Hainan Island, China, were collected. Genetic variation among the five populations was evaluated using inter-simple sequence repeats (ISSR) markers. Eleven ISSR primers gave rise to 133 discernible DNA fragments of which 103 (77.44%) were polymorphic, indicating a considerable genetic variation at the species level. However, the polymorphism at the population level was relatively low, with the percentage of polymorphic bands from 51.88% to 65.41%. The mean expected heterozygosity and Shannon’s information index were 0.227 1 and 0.348 9 respectively at the species level, 0.183 7 and 0.277 5 at the population level. Based on Nei’s Gst value, a large proportion of genetic variance (81.02%) was resided among individuals within populations, however, only 18.98% genetic variance was resided among populations. AMOVA analysis also indicated a similar genetic structure. The genetic identity between populations was 0.934 2 on average. UPGMA cluster analysis based on Nei’s genetic distance divided the populations into two main groups: Linshui population (LS) and Sanya population (SY) formed one group, Qionghai population (QH), Wenchang population (WC) and Dongzhai Harbor population (DZ) were in the other group. The Mantel test showed that genetic distance was significantly correlated with geographical distance.

Key words: Sonneratia alba , genetic diversity, ISSR, Hainan Island, Conservation