Molecular characterization of cultivated and wild Cajanus species using simple sequence repeat markers

Abstract

Twenty pigeonpea specific SSR markers were used to test the molecular diversity among 21 cultivated genotypes and three wild species. Twelve markers were monomorphic and twenty two alleles were produced by eight polymorphic markers. Ten markers were transferrable among the cultivated and wild species. The PIC value of the markers ranged from 0.081(PGM 3 and PGM 82) to 0.603 (PGM 106). The average PIC value of the markers was 0.30. Based on the dendrogram constructed using the dissimilarity values, 24 accessions were grouped into two main clusters. Main cluster I comprises all the cultivated genotypes, and wild species viz., Cajanus scarabaeoides and Cajanus cajaniolius. Cajanus sericeus formed the separate cluster (Main cluster II). Within the main cluster I, seven sub-clusters were observed. Cajanus scarabaeoides and Cajanus cajaniolius formed a separate sub-cluster within the main cluster I. Most of the diversity was observed in between the wild species and cultivated genotypes. There is no significant molecular diversity among the cultivated genotypes. Such a narrow genetic base is likely to represent a serious impediment to breeding programs in pigeonpea. This study suggested the need for broadening the genetic base of cultivated genotypes to improve the productivity of the crop.