Genetic Diversity Analysis of Ethiopian Barley (Hordeum vulgare L.) Genotypes Based on Agronomic Traits Using Cluster and Principal Component Analysis

Genetic diversity is essential for barley breeding, enabling the selection of desirable traits for improvement. Previous genetic diversity studies on barley have not been sufficient compared to the genetic resources available in the gene bank and ever-changing weather conditions. This study was therefore conducted to assess the extent of genetic variability and association of agronomic traits in barley genotypes at the Adet and Debark experimental stations during the 2023 main cropping season. Eighty-one barley genotypes were evaluated using a 9x9 simple lattice design. The analysis of variance revealed a high level of variability among barley genotypes. The first four principal components at Adet accounted for 78.4% of the total variation, while the first five components accounted for 80.5% at Debark. Traits such as grain-filling period, plant height, biomass, grain yield at Adet, grain yield, grain-filling period, harvest index, and thousand-seed weight at Debark contributed most to the first two components. The biplot analysis also revealed a strong negative correlation between days to heading and leaf rust severity with grain yield, harvest index, and grain filling period. Using hierarchical cluster analysis, the genotypes were grouped into five clusters at each location, each with a specific trait composition. and clusters I and III (71.84). At Adet, the greatest intercluster distance was between clusters II and IV (75.0), followed by clusters II and III (59.35), while at Debark, it was between clusters III and V (103.98), followed by clusters III and IV (82.14). The greater intercluster distance observed in this study indicates genetic diversity among the barley genotypes. This study also identified high-yielding genotypes (5, 9, 18, 32, 41, 50, 51, 53, 54, 60, 65, 68, 75) with grain yield potentials ranging from 2681.2 kg.ha -1 to 7291.6 kg.ha -1 at Debark and 80.5 kg.ha -1 to 4631.8 kg.ha -1 at Adet. These genotypes show potential as varieties for selection or as parents for hybridization. However, multi-year and multi-location trials are needed to confirm these results.