GENETIC VARIABILITY AND ASSOCIATION OF TRAITS IN WHITE LUPIN (Lupinus albus L.), GENOTYPES AT HOLETA, CENTRAL ETHIOPIA

Abstract

White lupin (Lupinus albus L.) is rich in quality protein, relatively tolerant to drought, soil salinity, and acidity, increases the fertility of soils and can contribute to improve white lupin food security and reduce malnutrition which has close associations with climate change. However, it is an underutilized crop in Ethiopia, therefore, as the first step for proper utilization of the crop, this study was conducted to assess the genetic variability of white lupin genotypes for yield, yield-related traits and nutrient contents of grain, and to estimate the association of traits. A total of 25 genotypes of white lupin were evaluated for 29 quantitative traits and 11 qualitative traits in 5 x 5 simple lattice designs at Holeta Agricultural Research Center during 2018/19. The genotypes showed significant differences for most of the traits except the leaf diameter, seed length and width, 100 seed weight, and potassium content of seeds. The variations of genotypes for yield and grain protein content ranged from 122 to 3206 kg ha-1 and 28.55 and 35.81%, respectively. The genotypes had 2763, 772.3 and 81.59 mg/kg of average phosphorus, calcium and iron contents of grain, respectively. The phenotypic (PCV) and genotypic (GCV) coefficient of variations varied from 4.39 to 29.54% and 3.41 to 28% respectively. Heritability in the broad sense (H2) and genetic advance as percent of the mean (GAM) ranged from 42.07 to 88.94% and 5.34 to 53.98%, respectively. The estimates of GCV, PCV, H2 & GAM were high to moderate for numbers of pod per plant, seed weight per plant, pod length, pod thickness, inflorescence length and Verticil number at genotypic and phenotypic levels, days to first flowering and number of branches per plant at the genotypic level and plant height and stem thickness at phenotypic level showed positive and significant correlation with grain yield. While numbers of seed per plant pod length and pod thickness negative significant correlation with yield at both level. These traits had also high to moderate positive indirect effects on grain yield via each other and through other traits at the genotypic level, suggested simultaneous selection for grain yield and these traits is possible. The six principal component axes, PCA1 to PCA6 accounted for 21.66 to 5.98%, respectively, and a total of 70.95% of the variation. The pair of genotypes had genetic distances between 0.38 and 19.17 estimated by Euclidean distances from 22 traits and the 25 white lupin genotypes grouped into four distinct clusters. Cluster IV consisted of 14 (56%) genotypes and Cluster I consisted of one genotype (4%), while Clusters II and III contained each five (20%) genotypes. The research results showed the presence of variations among white lupin genotypes and suggested that further evaluation of germplasm could be rewarding to exploit the genetic resource in the count