GENETIC VARIABILITY AND ASSOCIATION OF TRAITS IN BREAD WHEAT (Triticum aestivum L.) VARIETIES AT GITILO DALE, WESTERN ETHIOPIA

Abstract

In Ethiopia, a lot of improved bread wheat varieties have been released; however, the released varieties from different research centers were not tested at Gitilo Dale, Western Ethiopia for their genetic variability and association of traits in bread wheat varieties. In view of this, the study was conducted in Western Ethiopia at Gitlo Dale, Horroo Guduruu Wollega, with the objectives of determining the extent of genetic variability and association of traits with grain yield and their direct and indirect effects. Twenty five bread wheat varieties were evaluated in 5 x 5 triple lattice designs. However, the design was not efficient compared to RCBD. Hence, the collected data on 14 traits were analyzed according to the structure of RCBD ANOVA procedure. The result of analysis of variance for 14 traits showed highly significant differences at (P<0.01) among the varieties for all of the traits. Mean performances of 25 bread wheat varieties for 14 traits studied showed that the existences of plenty of variation among the varieties. Low (<10%) to high (>20%) estimates of genotypic and phenotypic coefficient of variations were observed for the traits studied. High (>60%) estimates of heritability values and moderate (10-20%) to high (>20%) genetic advance as percentage of mean for all traits were observed. High heritability coupled with high genetic advance as percentage of the mean was observed for grain yield, biological yield, harvest index, kernels per spike, spike length, and 1000 kernel weight. Biological yield, harvest index, hectoliter weight, total tillers per plant, productive tillers per plant, kernels per spike, and spikelets per spike had positive and significant correlation with grain yield both at genotypic and phenotypic levels. Path analysis indicated biological yield, harvest index, productive tillers per plant, kernels per spike, spikelets per spike, and spike length exerted direct positive effects on grain yield both at genotypic and phenotypic levels. This suggested that the use of these traits for indirect selection of varieties in grain yield improvement