Molecular Diversity Analysis as An Improvement Tool for Pigeonpea (Cajanus Cajan (L.))

Y Manju et al., 'Molecular Diversity Analysis as An Improvement Tool for Pigeonpea (Cajanus Cajan (L.))', Research Journal of Biotechnology, vol. 12(9), 2017

Simple sequence repeat (SSR) marker system was used to assess the genetic diversity among forty pigeonpea genotypes using eighty primer pairs. The banding pattern was recorded in the form of 0-1 data sheet which was analyzed using unweighted pair group method with arithmetic mean based on Jaccard's similarity coefficient. The results revealed that out of 80 SSR primers, 65 primers showed distinct polymorphism indicating the robust nature of microsatellites in revealing polymorphism. The number of alleles generated by each marker ranged from 2 to 7, with an average of 3.4 alleles. The polymorphism information content values for the SSR loci ranged from 0.24 to 0.86. Higher PIC value was observed for SSR primer CZ681974 (0.86) and lowest PIC value (0.24) was observed for the primer CZ682005. The SSR markers showed an average PIC value of 0.50. Markers with PIC values of 0.5 or higher are highly efficient in revealing genetic studies and are extremely valuable in distinguishing the polymorphism rate of a marker at a specific locus. The cluster analysis showed higher level of genetic variation among the genotypes. Similarity coefficients ranged from 0.45 to 0.93. The dendrogram based on the cluster analysis by microsatellite polymorphism, grouped 40 pigeonpea varieties into 2 major clusters which were further grouped into different sub-clusters. Based on the present study, the large range of similarity values for related genotypes using simple sequence repeats (SSR) provides greater certainty for the evaluation of genetic diversity and relationships for background selections during hybridization based crop improvement programmes