Molecular characterization and assessment of genetic diversity of sorghum inbred lines

Abstract

Selecting parents of diverse genetic base with contrasting phenotype is an important step in developing mapping populations for quantitative trait loci (QTL) detection and marker-assisted selection. We studied genetic diversity in 31 sorghum parents using 413 sorghum simple sequence repeats (SSR) markers. The polymorphism information content (PIC), a measure of gene diversity, varied from 0 to 0.92 with an average of 0.53 and was significantly correlated with number of alleles. The primers IS10215, IS10270 and IS10333 could differentiate all the 31 lines conclusively. Clustering analysis based on the genetic dissimilarity grouped the 31 parents into eight clusters and grouping was in good agreement with pedigree, race and geographic origin. Diverse pairs of sorghum parents were identified with contrast phenotype for various biotic and abiotic stresses with higher genetic diversity for developing recombinant inbred line (RIL) mapping populations to identify QTLs/genes for important traits in sorghum. One of the mapping populations resulted in the identification of QTLs for resistance to sorghum shoot fly and these QTL results were validated in a second mapping population.

Key words: Simple sequence repeats (SSR) markers, genetic diversity, sorghum, mapping parents.