Phenotypic performance of new pro-vitamin A maize (Zea mays L.) hybrids using three selection indices

The development of new bio-fortified maize hybrids is crucial for achieving food security and alleviation of micronutrient deficiencies. This study aims at assessing the performance of new pro-vitamin A maize hybrids and identifying potential high-yielding hybrids using base index, multivariate selection index, and rank summation index. Twenty-four pro-vitamin A maize hybrids and one hybrid check were evaluated in the rainy seasons of 2018 and 2019 at Ladoke Akintola University of Technology Teaching and Research farm in Ogbomoso, Nigeria. Hybrids were planted each year in a 5 × 5 α lattice design with three replications. Data collected on grain yield and agronomic traits were analysed. The hybrids showed significant (P < 0.001) variations for all measured traits except plant aspect and maize streak virus scores. The mean grain yield of hybrids over two years varied from 1,106 kg/ha (LY 1312-12) to 5,144 kg/ha (LY 1501-9). The highest yielding hybrid across the years had a 31% yield advantage over the single-cross hybrid used as a check. The base index had the highest selection differential (34%) for grain yield. The rank summation index had a strong correlation with the multivariate selection index (r = ‒0.86⁺⁺⁺) followed by base index (r = ‒0.56⁺⁺⁺). The three selection indices used identified three superior three-way cross hybrids (LY 1409-21, LY 1501-9 and LY 1501-1) with a slight change in rank order. These outstanding hybrids which combine high productivity with nutrients may be considered for advanced multi-location and on-farm testing before their release to farmers in derived savanna agroecology of Nigeria.