GENETIC VARIABILITY AND ASSOCIATIONS OF AGRONOMIC AND QUALITY TRAITS OF DURUM WHEAT (Triticum turgidum L.) LANDRACES IN BALE HIGHLANDS, ETHIOPIA

Abstract

Durum wheat is one of the most important cereal crops in Ethiopia. The national average productivity and quality of durum wheat is low due to lack of improved varieties and different biotic and abiotic constraints prevailing in the country these calls for development of improved durum wheat varieties. Knowledge on extent of genetic variability and identification of important characters and their interrelationship is a prerequisite for the development of high yielding and quality durum variety. The present study was carried out to assess the extent of genetic variability and character association among yield and yield related traits in selected durum wheat landraces. Forty-nine durum wheat accessions were studied for 20 traits at Sinana and Selka locations using 7x7 simple lattice design in 2018/19. Combined analysis of variance revealed significant differences among accessions for all studied traits, indicating the presence of considerable variability among accessions. A significant accession by location interaction effect was observed for most characters which indicate that differential performance of genotypes at each location. Combined over locations data showed protein content varied from 10.7 to 16.7% with the overall mean of 13.5%. Phenotypic coefficients of variation (PCV) ranged from 2.93 for test weight to 27.08 for productive tillers/plant while genotypic coefficients of variation (GCV) ranged from 0 for wet gluten to 16.43 for vitreousness. Low to high heritability was observed for all traits. Similarly, genetic advance as percent of mean varied from -0.20 to 31.24. High broad sense heritability and high genetic advance were obtained for grain yield (86.57 and 31.24) and vitreousness (75.76 and 29.39) respectively it means that, these characters could be improved easily through selection. Grain yield showed significant positive correlations with biological yield, harvest index, number of spikelets/spike, kernels/spike and productive tillers/plant both at genotypic and phenotypic levels, indicating the possibility of simultaneously improving these traits through selection. Path coefficient analysis revealed that, biomass and harvest index had high effect on yield and indicating that this trait could be considered as important trait in durum wheat yield improvement program. Forty nine studied accessions grouped in to ten clusters and the genotypes maintained under different groups had specific characters that contributed durum wheat variation. On average D2 values accessions Obsa (check) had the maximum value while, Acc7210 had minimum value and thus found to be the minimum divergent. Among the clustered groups, highest intra cluster distance was observed in cluster IV, VI, VII, VIII and IX (D2 = 6.4). The highest inter cluster distance was observed between cluster V and VI (D2 = 774.3) indicating there was divergence among clustered groups which is important for future crossing program. Generally, this study indicate that, Ethiopian durum wheat landraces contains a huge and valuable gene resource that will solve the challenge concerned with durum wheat especially, challenge concerned with productivity as well as quality. Overall, the present study revealed that there is sufficient variability existed in durum wheat genotypes tested that gives great opportunity for durum wheat improvement