Comparative analysis of genetic diversity among Indian populations of Scirpophaga incertulas by ISSR-PCR and RAPD-PCR

Genetic variation between 28 Indian populations of the rice pest, Scirpopha ga incertulas was evaluated using inter-simple sequence repeats (ISSR)-PCR assay. Nine SSR primers gave rise to 79 amplification products of which 67 were polymorphic. A dendrogram constructed from this data indicates that th ere is no geographical bias to the clustering and that gene flow between po pulations appears to be relatively unrestricted, substantiating our earlier conclusion based on the RAPD (random amplified polymorphic DNA) data. The dendrograms obtained using each of these marker systems were poorly correla ted with each other as determined by Mantel's test for matrix correlation. Estimates of expected heterozygosity and marker index for each of these mar ker systems suggests that both these marker systems are equally efficient i n determining polymorphisms. Matrix correlation analyses suggest that relia ble estimates of genetic variation among the S. incertulas pest populations can be obtained by using RAPDs alone or in combination with ISSRs, but ISS Rs alone cannot be used for this purpose.