Multi-trait evaluation of barley genotypes under semi-arid conditions using genotype × trait biplot analysis

Abstract

Identifying barley genotypes that combine high grain yield with favorable agronomic traits is a key objective of breeding programs. The present study aimed to evaluate a set of barley genotypes and identify superior ones using genotype × trait biplot analysis under rainfed conditions. Twenty barley genotypes were assessed in a field experiment conducted at Moghan, using a randomized block design with three replicates. The biplot analysis explained 68% of the total variation, indicating that the first two principal components effectively captured the complex relationships between genotypes and traits. Genotype G11 emerged as the most superior, demonstrating consistently high performance across a range of yield and yield-related traits, particularly in biomass weight and number of fertile tillers. Genotype G1 (cultivar Mahour) achieved a high grain yield primarily due to an increased thousand-grain weight, reflecting a grainfilling- driven yield strategy. Genotypes G14 and G18 exhibited relatively high yield with low variability, making them stable performers. The polygon view of the biplot distinguished genotypes with specific trait superiority from those showing poor performance, thereby facilitating the efficient elimination of underperforming genotypes such as G3 and G5. The ideal genotype view highlighted G11, followed by G13 and G19, as the genotypes closest to the ideal combination of high mean performance and low variability, confirming their broad desirability across the evaluated traits. Trait association analysis revealed strong positive correlations between biomass weight, number of fertile tillers, and tillers per plant, underscoring the importance of vegetative growth and sink capacity in yield formation under semi-arid conditions. Straw weight, grain yield per plant, and biomass weight exhibited the highest discriminatory power, while spike height and thousandgrain weight provided less useful information for genotype discrimination. The biplot analysis proved to be a highly effective tool for identifying superior barley genotypes and key selection traits, offering valuable insights for breeding programs targeting droughtprone environments.