Evaluation of CIMMYT and IITA Provitamin A Maize Inbred Lines for Carotenoid Content and Combined Drought and Heat Stress Tolerance in Sub‐Saharan Africa

Millions of people in sub‐Saharan Africa depend on maize for daily food, income and livelihoods. However, over‐reliance on maize‐based diets in sub‐Saharan Africa is associated with a high prevalence of Vitamin A deficiency. Provitamin A maize was introduced as a sustainable and reliable alternative to complement expensive vitamin A‐rich food; however, drought and heat stresses remain major constraints to its productivity. This study evaluated 192 provitamin A (advanced and Doubled Haploid) maize inbred lines for combined drought and heat stress tolerance using phenotypic traits and carotenoid content. The genotypes showed significant differences ( p < 0.05) for grain yield and phenotypic traits related to combined drought and heat stresses. Carotenoid content varied from 0.19–53.57 μg/g, with 35% of the total inbred lines having greater than the recommended breeding target of 15 μg/g. Path coefficient analysis revealed that plant height and ear position had a significant direct positive contribution, whilst anthesis date, anthesis‐silking interval and ear aspect had a negative direct contribution on grain yield under combined drought and heat‐stressed conditions. Inbreds TZMI1989, DSL19753, CLHP0478‐B, DS197‐338 and DS197‐224 were stable and contained sufficient carotenoid levels. We recommend that their combining ability effects and gene action for the target traits be assessed to ensure that desirable traits are inheritable. The drought and heat tolerant provitamin A maize hybrids that can be developed from the selected promising inbred lines have a high potential in solving both food insecurity and vitamin A deficiency problem especially in sub‐Saharan Africa region.