Estimation of Heterosis for Yield and Yield-attributing Traits in Maize (Zea mays L.)

Abstract

Heterosis breeding is an effective approach for improving grain yield and related traits in maize through the exploitation of hybrid vigour. Analysis of heterosis is essential for identifying superior parental combinations and developing high-yielding, climate-resilient hybrids, thereby contributing significantly to global maize productivity. The present investigation was conducted to estimate the magnitude of mid-parent heterosis, better-parent heterosis and standard heterosis for yield and yield-attributing traits in maize. Twelve diverse inbred lines comprising six lines and six testers were crossed in a line × tester mating design during kharif, 2021 to generate 36 F1 hybrids. These hybrids, along with the commercial check DHM-117, were evaluated during rabi, 2021-22 across three locations in Telangana namely Rajendranagar, Karimnagar and Madhira, using a randomized complete block design with three replications. The pooled analysis of variance revealed significant genotype, location and genotype × environment interaction effects for all the traits studied, indicating the existence of substantial genetic variability and environmental influence on trait expression. Based on both per se performance and heterosis estimates for grain yield and its component traits, the hybrids PFSR-51 × MGC-137, BML-11 × PFSR-46, BML-20 × PFSR-129, GP-111 × PFSR-151 and BML-20 × PFSR-95 were identified as the most promising hybrid combinations. These hybrids exhibited superior mean performance coupled with significant positive standard heterosis in the range of 15-30% for grain yield, indicating their potential for commercial exploitation and utilization in future maize hybrid breeding programmes. However, these promising hybrids should be further evaluated across multiple seasons and environments to assess their stability and adaptability before their utilization in large-scale breeding programmes or commercial cultivation.