Genetic Analysis of East African Sorghum Genotypes for Yield Components and Iron and Zinc Composition

Résumé fourni par la source

ABSTRACT Sorghum [ Sorghum bicolor (L.) Moench] is a vital cereal crop in dry regions worldwide. However, in sub‐Saharan Africa (SSA), grain yields from currently grown varieties remain low (< 1 ton/ha) and exhibit variable nutrient composition. Therefore, the objective of this study was to undertake a genetic analysis of selected East African‐adapted sorghum genotypes for grain yield and its components, and for iron (Fe) and zinc (Zn) composition, to identify better performing parents and develop new families for pipeline breeding. Ten preselected female and four male parents were crossed using the North Carolina Mating Design II to derive 34 families. The new families and parents were field‐evaluated using a 6 × 8 alpha lattice design with three replications across three sites during the 2022 growing season. Data on grain yield and associated agronomic traits, and Zn and Fe content, were recorded and subjected to combining ability and genetic analysis. General combining ability (GCA) and specific combining ability (SCA) effects were highly significant ( p ≤ 0.001) for the assessed traits. Nonadditive gene action predominantly determined trait inheritance, with Baker's ratios < 0.5, suggesting that heterosis breeding can enhance genetic gains, including for micronutrients. Parents NAROSorg1, Sila and TanzaniaAcc#42 showed desirable GCA effects for grain yield, making them ideal selections for breeding. Positive and significant ( p ≤ 0.05) GCA effects for Fe content were recorded for IS30310, Sila, NAROSorg1 and SudanColl#41Lodudu, whereas Sekedo, Sila and IS12750 recorded a similar genetic trend for Zn. Hence, these parents are suitable for biofortifying sorghum with Zn and Fe. The families, namely, NAROSorg1 × IS30310, NAROSorg1 × IS12750, SesoI × TanzaniaAcc#42, Sekedo × TanzaniaAcc#42, NAROSorg3 × SudanColl#7Lodoka and Seredo × IS12750 recorded desirable SCA effects for grain yield. The identified parents and families are recommended for breeding and genetic advancement for cultivar development.