Genetic differences between continuous and disjunct populations: some insights from sal (Shorea robusta Roxb.) in Nepal

Amsterdam

2010

S. 977-984

Monographie

173636

Sal (Shorea robusta Gaertn., Dipterocarpaceae) is a wind-pollinated tropical tree species found in southern Asia. We investigated the genetic diversity and structure at four microsatellites of 15 populations comprising continuous-peripheral and disjunct-peripheral populations inNepal. Estimates of genetic diversity (NA = 8.98, HO = 0.62, HE = 0.69) were similar when compared with those of other tropical tree species. A higher level of genetic diversity was observed in continuous-peripheral populations (NA = 9.61, HO = 0.67, HE = 0.72) as compared to disjunct-peripheral (NA = 8.04, HO = 0.55, HE = 0.64). Population differentiation was higher among disjunct-peripheral populations (FST = 0.043) than among continuous peripherals (FST = 0.012). There was a significant association between gene flow distances and genetic differentiation (r2 = 0.128, P B 0.007). No spatial arrangement of populations according to their geographical locations was found. Based on observed genetic diversity protection of some populations in continuous-peripheral range are suggested for the sustainable conservation of genetic resources of the species while protection of some disjunct-peripheral populations are also recommended for conserving rare alleles.
Keywords Conservation ; Shorea robusta ; Microsatellites ; Genetic diversity ; Peripheral populations ; Nepal