Abstract:
In West Hararghe, wheat is produced on thousands of hectares, but the productivity is much lower than the average of national and regional states due to moisture stress resulting from
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erratic rainfall. Developing varieties in the area is one of the measures to improve the production and productivity of wheat. This pre-breeding research was conducted to assess the genetic variability in bread wheat genotypes and determine the association among traits. Sixty-four genotypes including two standard check varieties were evaluated using 8 x 8 simple lattice designs at Hirna in 2022. The ANOVA results revealed significant (P<0.01) differences among genotypes for all tested traits. Thirty genotypes had 10.17 to 45.35% higher grain yield than better-performing check. Genotypic and phenotypic coefficients of variation ranged from 4.90 to 14% and 5.70 to 14.46%, respectively. The heritability and genetic advance as the percent of the mean ranged from 63.89 to 96.28% and 8.7 to 27.97%, respectively. Grain yield at both levels showed positive and significant correlations with all traits. Biomass yield, harvest index, seeds per spike, and 1000 seeds weight had a positive direct effect on yield at both phenotypic and genotypic levels. Thus, these traits suggested for indirect selection of genotypes for yield. The first four principal components (PC) with Eigen values >1 accounted for 73.39% of the total variability of genotypes. The first PC contributed to 29.15% whereas PC2, PC3, and PC4 accounted for 17.83, 15.86, and 10.54% of the total variation, respectively. Euclidean distances for (2016 pairs) of genotypes ranged from 1.59 to 10.95 and the genotypes grouped into nine distinct clusters. Cluster III, II, and V consisted of 27, 18, and 5 of genotypes, and the other clusters consisted of 1 to 4 genotypes. The genotypes under clusters V and I had higher mean values for almost all traits, and the other clusters consisted of genotypes with higher mean values for two or more traits than the overall mean of genotypes. Thus, it is concluded that developing varieties for high yield in the study area is possible through further evaluation and selection of better performing genotypes.
