Evaluation of advanced generations of sesame (sesamum indicum l.), mutant lines at selected sites in western Kenya

Abstract

Sesame is an important oil crop that is well suited for the marginal areas whose potential has not been fully exploited in Kenya. A mutation breeding experiment was initiated at Kabete in the 1990' s to enhance the genetic variability of the crop from which desirable cultivars could be identified. Several desirable mutant lines now in advanced generations have been developed. This study was carried out to evaluate the adaptability of advanced generations of some of these selected sesame mutant lines at two sites (Siaya Farmers Training Center and Maseno University) in western Kenya. The objectives were to study the performance of advanced mutant lines and identify the most promising ones for cultivation in western Kenya. Thirty mutant lines and four checks were grown in three replicates for two seasons using a completely randomized block design. Each of the cultivars was sown in three rows spaced 50 em apart with inter-plant spacing of 10 ern. The seedlings were thinned at 10-15 em height. Data on several agronomical traits were recorded during crop growth period. Mean performance showed that mutant line Mun 096/1/k5/2/4 had the highest performance as far as yield and yield components were concerned. Variations among the studied genotypes were also noted, with highest variation coming from seed yield per plant. The data were also subjected to analysis of variance for each environment for all the traits as well as across the environments to assess the genotype by environment interactions. The effects of environment, genotype and genotype by environment interactions were highly significant for all traits studied. Variations due to genotype by environment interactions were greater than those due to genotypic differences for all traits except 1000-seed weight. Genotype x sites x seasons contributed most to the genotype by environment interactions for all traits except for number of days to flowering, biomass yield and harvest index. The highest yielding and best-adapted mutant line was Mun 096/11k5/2/4 followed by MUll 50/1/121 although its yield was not significantly different from the best check cultivar Spssikl16. These two mutant lines are therefore recommended for further tests in western Kenya. With regard to analysis of correlations, gram yield showed a high positive and significant correlation between grain yield and biomass yield, harvest index and 1000- seed weight. Seed yield also showed a moderate positive association with plant height, number of capsules per plant and percent oil content. Path analysis revealed that biomass yield and harvest index were the major contributors toward the seed yield.