Evaluation of MAS-derived Inbreds and Hybrid Variants of Maize Hybrid 'Hema' for Resistance to Late Wilt Disease (Magnaporthiopsis maydis)

Abstract

Late wilt disease (LWD), caused by Magnaporthiopsis maydis, is a serious constraint in maize production, particularly affecting hybrids like ‘Hema’. In this study, 11 inbred lines, developed from the susceptible parent NAI-137 using marker-assisted selection (MAS), were evaluated alongside their hybrids (crossed with Hema's original male parent) under LWD-endemic conditions at Gandhi Krishi Vignana Kendra (GKVK), Bengaluru using an alpha lattice design with three replications. The inbreds displayed enhanced resistance (lowest LWD score: 3.11), and their hybrids exhibited improved agronomic traits. Notably, hybrids H3 and H8 outperformed the check Hema by 11.25% and 2.15% in yield respectively, with superior resistance (scores of 2.8 and 3.8). Statistical analyses revealed significant genetic variation, with strong trait correlations. Principle component analysis (PCA) explained 60.2% of the total variation. Grain yield showed strong positive correlations with cob width, cob weight per plant, and cob length. Cluster analysis grouped the genotypes into two distinct clusters, suggesting clear phenotypic diversity. The results highlight the potential of MAS-derived inbreds for developing high-yielding, disease-resistant maize hybrids suitable for LWD-prone environments.