Heterosis, general combining ability (GCA) and specific combining
ability (SCA), and their effects were studied for five major traits in
a design II mating system in pure sorghum lines obtained by induced
mutation. Significant genotype effect was detected for all traits. GCA
effects were highly significant for all traits studied. Effects due to
SCA were of less magnitude except on plant height. Some parents were
identified having high GCA for grain yield and low or negative GCA for
days to anthesis, which were considered as good combiners. The ratio of
general combining ability to specific combining ability indicated that
additive gene effect was the predominant type of gene action for most
yield contributing traits. High positive heterosis for grain yield and
its components, including days to anthesis and plant height, as found
for more than half of the hybrids studied. Some pure lines evaluated
may be used directly as male parents of hybrids and as breeding lines
for incorporation into selection programs. The results demonstrate for
this set of genotypes the considerable potential that exists for
improving the yield performance of sorghum in Western Africa.
Importance of genotype x environment interaction underlines the
necessity of evaluating breeding materials under a broad range of dry
land conditions. This research would assist decisions on parental
selection for more extensive study of heterozygosity involving large
numbers of genotypes
