Combining Ability and Heterosis over Environments for Stalk and Sugar Related Traits in Sweet Sorghum (Sorghum bicolor (L.) Moench.)

Abstract

Till date only one sweet sorghum hybrid CSH 22SS has been released for general cultivation in India and the current levels of new hybrids are unable to surpass this hybrid. The objective of this study was to assess the general and specific combining abilities of eight parents and 16 hybrids respectively at three semi arid locations by following a line × tester mating design. Significant differences among environments, testers, environments × testers and environments × line × tester effects were observed for all traits suggesting the environmental influence on testers and the interactions. The variance component estimates of specific combining ability (SCA) were greater than that of general combining ability (GCA) for total biomass, juice extraction and grain yield indicating the non-additive control of genetic variation while the GCA variance was higher than the SCA variance for fresh stalk yield, juice yield, brix content, total sugar yield and computed bioethanol yields indicating additive gene action. Among females, DMS 28A for fresh stalk, juice and grain yields and DMS 25A for brix content were promising. Rio was a potential male parent for fresh stalk yield, total sugar content, computed bioethanol and grain yields. These parents can be exploited to address ethanol production from juice without compromising on grain yields. The best hybrids for total biomass, fresh stalk yield, juice yield, juice extraction, total sugar content and computed bioethanol yields were DMS 13A × Rio and DMS 23A × RS 647 and after adequate testing across many locations, these hybrids are recommended for commercial exploitation for ethanol production.