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
