PARENTAL SELECTIONS IN SORGHUM (SORGHUM BICOLOR L.) ON THE BASIS OF HETEROSIS AND COMBINING ABILITY IN ASSOCIATION WITH SSR DIVERSITY IN SUB-TROPICAL PLAINS OF UTTARAKHAND, INDIA

Selection of genetically diverse and complementary parents for important key traits is most difficult task in any hybrid breeding programme. The objective of this study was to estimate heterosis and relative combining abilities with associated SSR diversity for identification of unique sorghum genotypes. A total of forty crosses and thirteen parental lines including five cytoplasmic male sterile (CMS) lines and eight pollinator lines with two standard check varieties were phenotyped using six agro-morphological traits and genetic diversity was estimated by using five polymorphic SSR markers. Sorghum genotypes were crossed with CMS lines using a line × tester mating design and 40 hybrids, 13 parents and two check varieties were field-evaluated using alpha lattice design with three replications. General combining ability (GCA), specific combining ability (SCA) and heterosis for grain yield and other associated attributes were determined. SSR diversity estimates were ranged from 0.54 to 0.90. Among CMS lines, 11A2 and MR750A2 and among pollinators, UPC2 and M35-1 were reported as best general combiners. A2 cytoplasm was found to be more efficient to produce more heterotic combination with experimental lines. Cross, 11A2 x UPC2 gave best results of heterosis for most of the characters. MR750 A2 x UPC2, 11A2 x UPC2, ICSA467 x UPC2, ICSA467 x CS3541, ICSA 467 x RS29, ICSA 467 x M35-1 and 11A2 x M35-1 revealed significant and positive values of heterosis, SCA and GCA. However, no direct correlation was detected with heterosis and molecular diversity for most of the characters. These results may be used for the exploitation of hybrid vigor in sorghum breeding programmes