Translation of phenotypic diversity of Sorghum bicolor axillary branched mutant into exploitable heterosis.

Lack of variability in sorghum is the main reason for the stagnation in crop improvement including low heterosis. Studies on somaclonal mutations of sorghum have led to the development of a diverse axillary branched grain sorghum mutant, Sb ABM of postrainy season variety A-1 (Annigeri-1) which bears multiple panicles. Considering its developmental significance and phenotypic diversity, this mutant was subjected to detailed genetic analysis. To exploit its genetic potentiality, the mutant was involved in a full diallel study along with ruling varieties to assess the combining ability and to quantify the magnitude of heterosis. Sb ABM performed exceptionally well in hybrid combinations for all the traits. Mean squares due to genotypes were highly significant for all the traits. The results on general combining ability revealed that Sb ABM was significantly better general combiner for all the traits studied. Majority of the hybrids involving Sb ABM as parental line exhibited high degree of heterosis for most of the traits, finally contributing to overall plant's vigour. However, Sb ABM did not restore fertility on both milo and maldandi cytoplasm. [ABSTRACT FROM AUTHOR]