Gene action of selected grain and forage dual purpose sorghum genotypes

Sorghum is an important food and feed source in mixed crop-livestock production systems where its dual usage is a preferred option, especially among the resource poor small-scale farmers. This study was undertaken to estimate the combining ability of grain and forage sorghum genotypes in F1 combinations for several traits as a criteria for improving dual purpose sorghum cultivars. A total of 23 crosses were evaluated alongside their parents at three locations in two seasons. Results indicated that the gene action for the traits under observation was controlled by both additive and non-additive genetic effects. Majority of the parental lines had significant GCA estimates for all traits except line 20 for grain yield, lines 22 and 34 for plant height, line 35 for leaf-stem ratio, and line 22 for days to flowering. Significant (P d” 0.05) SCA estimates were prominent in majority of the individual parental combinations for all traits except leaf area and leaf-stem ratio. The results of this study suggested that both inter and intra allelic interactions were involved in the expression of the traits. The predominance of additive genetic control implies that use of parents with suitable significant GCA effects is most appropriate for improving sorghum cultivars for dual purpose while the different parental combinations (grain by forage, forage by grain) that showed high specific combining ability indicated the role of dominance gene action.