Comparative Analysis of Genetic Diversity among Cultivated Pigeonpea (<i>Cajanus cajan</i> (L) Millsp.) and Its Wild Relatives (<i>C. albicans</i> and <i>C. lineatus</i>) Using Randomly Amplified Polymorphic DNA (RAPD) and Inter Simple Sequence Repeat (ISSR) Fingerprinting

Abstract

Genetic relationships of 16 cultivars of pigeonpea ( Cajanus cajan (L) Millsp.) and its two wild relatives ( C. albicans and C. lineatus ) from different parts of the India were analysed using 22 random amplified polymorphic DNAs (RAPDs) primers and 10 inter simple sequence repeats (ISSRs) primers. Twenty two RAPD primers yielded 151 polymorphic markers (71.2%) with an average of 6.8 polymorphic band/primer. Cluster analysis based on these 151 RAPD markers revealed relatively low level (0.434 - 0.714) of genetic diversity among cultivars and high level of diversity between cultivars and wild relatives. Ten ISSR primers produced 100 bands across 16 cultivars and its wild relatives out of which 93 (93%) were polymorphic with an average of 9.3 polymorphic band/primer . Cluster analysis based on these 93 ISSR markers also revealed relatively higher level (0.328 - 0.827) of genetic diversity among cultivars as compared to RAPD markers. The polymorphic markers obtained by both RAPD and ISSR primers were pooled and the genetic diversity analysis based on these 244 markers was analysed. Jaccard’s similarity coefficient obtained by pooled data revealed very narrow range (0.477 - 0.720) among cultivated and high range between cultivated and wild species C. albicans (0.240 - 0.331) and C. lineatus (0.163 - 0.193). In the UPGMA based dendrogram the 16 cultivars were grouped into three distinct clusters. Cluster I contained two genotypes, cluster II had six and cluster III had eight genotypes. Principal components analysis (PCA) also resulted in similar pattern as that of UPGMA based analysis. The first three PCs contributed 56.26%, 5.71% and 4.97% of variation, respectively, with cumulative variation of the first three PCs was 66.96%. Both the markers and the combined data revealed similar pattern with narrow diversity among cultivars and higher diversity between cultivars and wild one, but the genetic diversity range obtained by ISSR markers was relatively higher as compared to RAPD and pooled data. Furthermore, both the markers also correlated the clustering of stress resistant genotypes together. Cultivar Pusa-2002 possessed more diversity with other genotypes in ISSR dendrogram.