Morphological diversity and DUS characterization of wheat ( Triticum aestivum L.) genotypes using multivariate analysis across contrasting sowing environments in Chitwan, Nepal

Systematic characterization of wheat germplasm is essential for varietal identification, germplasm conservation, and plant variety protection, yet multivariate Distinctness, Uniformity, and Stability (DUS)-based characterization of Nepalese wheat accessions remains limited. This study characterized 50 wheat genotypes comprising 49 accessions from the National Agriculture Genetic Resource Center (Genebank), Nepal, and one released check variety (Vijay) using nine qualitative DUS descriptors across three sowing dates at Rampur, Chitwan, Nepal. Phenotypic diversity was quantified using Shannon-Weaver (H′), Simpson (1-D), and evenness (E) indices, pairwise associations via Cramér’s V, and genotype classification using Ward’s linkage clustering based on Gower distance, while multivariate diversity was explored through Multiple Correspondence Analysis (MCA). Spike-related traits showed the greatest phenotypic diversity, with ear shape, ear density, and auricle hair being the most diverse traits, whereas peduncle attitude exhibited the lowest diversity. The strongest pairwise association occurred between awn type and ear pubescence (V = 0.56). MCA explained 28.1% of the total inertia across two dimensions, with very dense ear density and very strong ear pubescence contributing most to genotype differentiation. Cluster analysis identified eight morphologically distinct groups, and stable qualitative trait expression across sowing environments provides a foundation for future wheat breeding, germplasm conservation, and varietal identification.