Genotypic Variability, Heritability, Genetic Advance and Associations among Characters in Ethiopian Durum Wheat (Triticum durum Desf.) Accessions

Abstract

A field experiment was conducted at Geregera (11° 45’ N latitude and 38° 45’ E longitude) in north Wollo, Ethiopia during the 2003 cropping season with the objectives of estimating genotypic variability, heritability, genetic advance and associations among yield and yield-related characters of durum wheat. Forty four randomly taken Ethiopian durum wheat accessions were evaluated using randomized complete block design in three replications. Analysis of variance showed significant differences (p < 0.05) among the durum wheat accessions for all the characters considered. Genotypic coefficients of variation (GCV %) were medium for spike length (12.5%) and kernel yield plant -1 (12.3%). Broad sense heritability were high for spike length (89.2%), plant height (87.1%) and thousand kernels weight (80.2%), indicating that these characters were predominantly controlled by genetic factors. Maximum heritability in broad sense coupled with high genetic advance were exhibited for spike length, plant height and thousand kernels weight, implying that phenotypic selection could identify superior genotypes for these traits. Genotypic correlation analysis revealed that grain yield had strong positive associations (p < 0.01) with kernel yield plant-1 (r g = 0.89), plant height (r g = 0.84), thousand kernels weight (r g = 0.82), biomass yield (r g = 0.80) and number of kernels spike-1(r g = 0.78), where biomass yield and harvest index exerted maximum positive direct effects on grain yield. On the other hand, days to heading had a significant negative correlation (p < 0.01) with grain yield (r g = -0.75) which exerted maximum negative direct effect on grain yield. Therefore, earliness coupled with high biomass yield could be considered as an indirect selection criterion for durum wheat grain yield improvement in moisture stressed areas. Keywords: Genetic; Genetic Advance; Harvest Index; Heritability; Variability