Identification of superior maize double haploid lines for compact plant architecture through multivariate and path analyses

Maize (Zea mays L.) productivity under high-density planting is strongly influenced by plant architecture, physiological efficiency, and yield components. However, improving yield under dense planting conditions remains challenging due to complex interactions among architectural, physiological and reproductive traits as well as multicollinearity that complicates simultaneous trait selection. The present study evaluated 70 maize double haploid (DH) lines to identify superior genotypes with compact plant architecture suitable for high-density cultivation. The DH lines were assessed during Kharif 2023 and Rabi 2024 using an Augmented Block Design II, recording 21 morphological, physiological, phenological, and yield-related traits. Analysis of variance revealed highly significant genetic variation among DH lines for most traits, indicating substantial exploitable variability. Path analysis identified plant height and photosynthetic rate as major contributors to grain yield through strong positive direct effects, while ear diameter and ear length emerged as key yield components. Principal component analysis extracted seven principal components explaining 73.67% of the total variability highlighting considerable multivariate diversity among the DH lines. Hierarchical cluster analysis grouped the DH lines into three distinct clusters, confirming genetic divergence and enabling effective classification of genotypes based on trait performance. By integrating multivariate and causal analytical approaches, this study provides a systematic framework for dissecting complex trait interactions and identifying genotypes with optimal plant stature, efficient canopy architecture, and superior yield attributes. The findings contribute to the development of high-density tolerant maize ideotypes and offer valuable genetic resources for accelerating modern maize breeding programs.