Heterosis and combining ability for yield and resistance to grain mold in tannin-free photoperiod-insensitive sorghum [Sorghum bicolor (L) Moench] in Senegal

Increasing sorghum production per unit area in the farmer’s field by developing high yielding tannin-free and grain mold tolerant varieties in Senegal is the goal of the present study. Line × tester mating design was used to cross eleven tannin-free non-photoperiodic male fertile sorghum varieties with two male-sterile A-lines to produce 22 F₁ hybrids. These hybrids along with the thirteen parents and one grain mold resistant hybrid check were evaluated under natural grain mold infestation in two contrasted sites using a 6 × 6 lattice design with three replications. Results on combining ability suggested that additive gene actions were important in the control of grain mold resistance while non-additive gene actions were preponderant in the inheritance of grain yield. The parental lines F2-20, Macia, Faourou, and Dorado were the best general combiner for grain mold resistance. Of these, Dorado was identified as the best combiner for yield and yield components. Additionally, the hybrid CE310-31A × Sureño was identified as the best hybrids combination for yield, yield components and grain mold resistance. Furthermore, the hybrid crosses CE310-31A × F2-20, CE310-31A × Sureño and AVG-1 × Dorado showed the best mid-parent heterosis for grain yield and resistance to grain mold. Moreover, based on their combining ability and heterosis, seven hybrids were identified for their resistance to grain mold and high yielding. These hybrids could be tested in multi-location trials for a subsequent release.