Genetic variability and association of yield and yield related characters in bread wheat (Triticum aestivum L.) Varieties

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