Exploration of Standard Heterosis in Single-Cross Inbred Line Combinations of Maize (Zea Mays L.)

Abstract

Standard heterosis is an important criterion for identifying maize hybrids with practical breeding and commercial value. The present investigation evaluated standard heterosis for grain yield and associated quantitative traits in newly developed single-cross maize hybrids. Thirty-six F₁ hybrids were generated by crossing 12 diverse inbred lines using a line × tester mating design during kharif 2021 at the Maize Research Centre, Rajendranagar. The hybrids, together with the commercial check Bio-9544, were evaluated during rabi 2021–22 across three agro-climatic zones of Telangana using a randomised complete block design with three replications. Data were recorded for days to 50% tasselling, days to 50% silking, days to maturity, plant height, ear height, ear length, ear girth, number of kernel rows per ear, number of kernels per row, 100-seed weight and grain yield. Pooled analysis of variance indicated significant differences among genotypes, environments and genotype × environment interactions for all traits, demonstrating the presence of genetic variability and differential genotype performance across locations. All hybrids showed significant negative standard heterosis for days to 50% tasselling and days to 50% silking. For grain yield, four crosses, namely BML-11 × PFSR-129, BML-11 × PFSR-46, GP-35 × MGC-137 and PFSR-51 × MGC-137, recorded a yield advantage of 14.62–24.76% over Bio-9544. These hybrids also expressed favourable heterosis for key yield-contributing traits and may be considered promising genetic materials for further multi-environment evaluation.