Studies on heterosis combining ability stability and molecular diversity in sweet sorghum Sorghum bicolor L Moench

Abstract

An investigation was carried out during the year 2004 and 2005 to know the heterosis newlineand combing ability among 144 sweet sorghum hybrids developed by crossing nine females newlineand sixteen male lines obtained from ICRISAT in a line × tester fashion. Further, the study newlinealso aimed at identifying the stable sweet sorghum hybrid combinations and suitable newlineenvironment for cultivation of sweet sorghum and also to assess the extent of genetic newlinediversity among all the sweet sorghum accessions using Random Amplified Polymorphic DNA newline(RAPD) markers. newlineThe results indicated higher amount of variability among the parental material which newlinewas evident from high amount of heterosis realized for juice volume, juice weight and grain newlineyield parameters. However; there was negligible amount of heterosis observed with respect to newlinebrix and 1000-seed weight. Among the parental lines ICSB474 and ICSB77 (among females) newlineand SSV74, SSV84 and ICSR93034 (among males) were found to be good general newlinecombiners for biomass, juice and grain yield traits. Experimental hybrids ICSA474 × SSV84, newlineICSA474 × ICSR93034 and ICSA264 × ICSR93034 recorded significantly higher standard newlineheterosis values consistently during both the experimental years. newlineThe genotypic differences among the limited number of hybrids tested for Genotype x newlineEnvironment interaction were considerably high. However, normal kharif (E1) environment newlinewas found to be ideal environment for cultivation of sweet sorghum with the F1 hybrid newlinebetween ICSA293 × SPV1411 emerging out as the most stable hybrid combination when newlinetested for juice related traits across environments. The extent of genetic variation among all newlinethe twenty seven sweet sorghum accessions was high as evident from 93.49 % newlinepolymorphism by RAPD markers. Among the primer pairs, OPJ-6, RKAT-9 and RKAT-6 were newlinefound to be highly polymorphic. And the dendrogram eventually partitioned all the genotypes newlineinto three different clusters with most of the females falling into one single cluster.