Chromosome Stability and Inter-population Genetic Variability in a Tree Mangrove Xylocarpus granatum Koen. (Meliaceae) as Revealed by RAPD Markers

抄録

Detailed chromosome analysis of 8 populations of Xylocarpus granatum showed a constant somatic chromosome numbers of 2n=48 with a very symmetric karyotype. Structural details recorded no such major variation in the chromosome morphology. Random amplified polymorphic (RAPD) markers were used for determining the genetic diversity among 8 populations of this minor tree mangrove species. Individuals collected from several sites in north-east coast of India were analyzed for their genetic relationship. A total 444 amplicons were generated among the ecotypes out of which ~67% bands were found polymorphic. Inter population polymorphism among 8 populations of X. granatum varied between 36.25 to 72.5%. Clustering based on similarity index was done following Unweighted Pair Group with Arithmetic mean (UPGMA) method and intra-genetic relationships were analysed. The obtained dendrogram of the RAPD data showed prominent patterns of interpopulation relationships that are discussed in the light of the respective habitats of the ecotypes distributed in different mangrove pockets of the north-east Indian sea coast. It was evident from RAPD data that high degree of divergence exists among 8 studied populations, which suggests their adaptation in various microclymatic condition is suitable for the specific habitat of a particular ecotype.