Abstract:
Twenty one bread wheat (Triticum aestivum. L) varieties were evaluated for ten quantitative traits in
RCBD at two locations, Holeta and Ginchi. The overall objective was to study the extent of genetic
variation and association among grain yield and ten yield related traits. The genotypes differ significantly
for all of the traits and the relatively wide range of the mean values for most of the characters indicated the
existence of variation among the tested genotypes. Estimates of phenotypic (PCV) and genotypic (GCV)
coefficients of variation were generally moderate for most of the characters. The PCV values were greater
than the GCV values. Moderate PCV and GCV values were exhibited by 1000-grain weigh at both
locations. Moderate to high PCV and GCV were observed for grain yield, number of tillers, days to
heading, pant height, number of spiklets per spike, number of grains per spike and, harvest index at the two
locations combined. Thousand grain weights showed high heritability at both locations. All studied
characters showed high heritability at the two locations combined. In combined analysis estimate of GAPM
was high for grain yield per plant, number of tillers, number of spikelets per spike, number of grains per
spike, harvest index, days to heading and plant height and moderate for days to maturity and spike length.
Thousand grain weight had high GAPM at Ginchi and Holeta. The D2
analysis showed the 21 genotypes
grouped into five clusters. This makes the genotypes to become moderately divergent. The principal
component analysis revealed that five principal components PC1 to PC5 which are extracted from the
original data and having latent roots greater than one accounting nearly for 86.01% of the total variation.
Grain yield had significant and positive correlation with HI at Ginchi location. The same trait showed
positive and significant phenotypic and genotypic correlation with, number of spikelets per spike, number
of grains per spike and harvest index and it had positive and significant association with days to heading at
genotypic level only at combine over locations. Path coefficient analysis showed that harvest index and
number of tillers exerted positive direct effect at combined over locations. While these two characters can
be considered for selection, these wheat genotypes need to be crossed and selected to develop high yielding
pure line variety
