Evaluation of mid-parent and best-parent heterosis for grain yield in selected maize inbred lines

Abstract

Maize (Zea mays L.) is a major crop with global importance for food, feed, and industry. Improving yield through hybrid breeding remains a key objective, and heterosis plays a central role in achieving superior performance. This study evaluated mid-parent heterosis (MPH) and best-parent heterosis (BPH) for grain yield in 19 maize hybrids derived from genetically diverse inbred lines. Field experiments were conducted in 2024 near Cucuruzeni, Orhei district, Republic of Moldova, under chernozem soil conditions and moderate drought stress. A partial diallel mating design was used, and trials were arranged in a randomized incomplete block design with two replications. Yield was measured at harvest, and heterosis was calculated using standard formulas. Results revealed significant variability, with MPH ranging from 33.7% to 76.3% and BPH from 13.3% to 71.6%. The hybrid 2110 × 2126 showed the highest yield and BPH, while 2132 × 2127 had the highest MPH. The findings confirm the role of non-additive gene effects and highlight promising parental combinations for future hybrid development.