Genetic variability and associations of traits in indigineous and exotic sesame (Sesamum indicum L.) Genotypes at werer, northeastern-ethiopia

Abstract

In Ethiopia the productivity of sesame is low and below the world avergae. This low productivity is attributed to certain yield constraints mainly lack of high yielding improved variety. Understanding of genetic variability and association of characters becomes essential. Therefore, this study was conducted to estimate the extent of genetic variation and association among yield and 19 yield components. A total of 100 sesame genotypes were evaluated in 10x10 triple lattice design at Werer from 2017 to 2018 for two cropping seasons. The combined analysis of variance over the two seasons showed that the genotypes differed significantly for all the characters studied. Higher phenotypic (PCV) and genotypic (GCV) coefficients of variation were observed for shattering resistance, whereas plant height, number of capsule per plant, harvest index and seed yield showed medium PCV and GCV values; it indicating weak influence of environment. High heritability values coupled with moderate to high genetic advance as a percent of mean (GAM) were observed for shattering resistance, plant height, capsule per plant, harvest index and seed yield; this implies that the experssion of the charactrs geverned by additive gene acction. Seed yield showed positive and significant correlation with length of capsule bearing zone, length of first capsule, capsule length, capsule per main axis number of capsule per plant, harvest index and oil content. This signfied that the improvement of one traits will simultaneously improve the other. Path coefficient analysis revealed capsule per main axis, capsule per plant and harvest index had positive direct effect on seed yield.The D2 analysis exhibited that 100 sesame genotypes grouped into seven clusters. This makes the genotypes to become moderately divergent. Principal component analysis revealed that seven principal components have accounted for 78.67% of the total variation. The present study revealed that to increase sesame seed yield, the genotypes should possess more number of capsules per main axis, capsule per plant and high harvest index. This study suggested these characters were important yield contributing traits and selection based on these characters would be most effective. However, in order to give confirmative result further studies should be conducted at multiple locations.The present study was based on morphological traits only. Hence, supporting the assessment of sesame genetic resources with molecular markers and high throughout molecular data for marker assisted breeding should be considered in the future.