Genetic diversity and morphological characterization of wheat (Triticum aestivum L.) landraces in Nepal

This study examined the genetic diversity and phenotypic characteristics of 60 wheat landraces from 24 districts across Nepal. The study was conducted at the National Agriculture Genetic Resources Centre (NAGRC) in Khumaltar, where it employed a non-replicated augmented block design to assess eight qualitative and sixteen quantitative traits based on Bioversity International descriptors. The Shannon-Weaver diversity index (H') for wheat landraces varies from 0.457 to 0.979 across qualitative traits. Tillering capacity shows the highest diversity at 0.979, and glume hairiness has the lowest diversity at 0.457. The coefficient of variation (CV) for the quantitative traits of wheat landraces varied widely; percentages ranged from 7.58% for days of heading, suggesting relatively low variability, to 36.56% for spike exertion, indicating high variability among the samples. Principal Component Analysis (PCA) with an eigenvalue greater than 1 revealed that five principal components accounted for 70.95% of the variability, with traits like plant height and spike exertion playing pivotal roles in genotype differentiation. A dendrogram generated using a UPGMA clustering approach organized the landraces into two groups. Cluster-I consists of 56 accessions (93.33%), and Cluster–II consist of 4 Accessions (6.67%) separated by 2374.99, indicating phenotypic differentiation between the groups. These findings underscore the importance of targeted breeding programs based on specific trait performance, supported by further correlation analysis to identify optimal characteristics for breeding. This research highlights the need to continue evaluating these landraces through environmental trials and biotechnological approaches to fully capitalize on their genetic potential for improving wheat cultivation.