Combining ability and heterosis among sorghum (Sorghum bicolor [L.] Moench) lines for yield, yield-related traits, and anthracnose resistance in western Ethiopia

Abstract

High-yielding sorghum genotypes with farmer-preferred agronomic traits and durable anthracnose resistance are key drivers of productivity and adoption. The objective of this study was to determine combining ability effects and heterosis of selected sorghum lines for yield, yield-related traits, and anthracnose resistance, to identify superior parents and families for further selection and breeding. Nine selected sorghum genotypes with known resistance to anthracnose were crossed, using a 9 × 9 half-diallel mating design. Parents and F1 families were evaluated across two locations, using a randomized complete block design with three replications. Significant (P < 0.01) genotype, location, and genotype × location interaction effects were observed for most traits and anthracnose resistance, indicating mixed performances of the tested genotypes, allowing for further selection. General combining ability (GCA) and specific combining ability (SCA) effects were significant (P < 0.01) for most traits, including anthracnose resistance, indicating both additive and non-additive gene action underlying inheritance of the studied traits. Parental genotypes such as Bt-623, 210903, 234112, and 226057 showed positive and significant GCA effects for grain yield. Parents 74222, 214852, and 71708 showed negative and significant GCA for anthracnose resistance. The following families: Bt-623 × 210903, Bt-623 × 234112, Bt-623 × Chemeda, Bt-623 × Gemedi, 210903 × 234112, 210903 × 71708, 74222 × 234112, 74222 × 226057, 234112 × 71708, 226057 × 214852 and 226057 × 214852 expressing positive SCA effects for grain yield were identified. The following desirable families were selected: 174222 × 234112, Gemedi × 71708, Bt-623 × 234112, Bt-623 × Gemedi, 226057 × 71708, Chemeda × 71708, and Gemedi × 71708 with negative SCA effect and low anthracnose severity. These are useful sorghum populations for resistance breeding or direct production.