ASSESSMENT OF GENE ACTION BY LINE X TESTER MATING DESIGN IN SESAME (SESAMUM INDICUM L.) ELITE GENOTYPES

Abstract

Although sesame is self-pollinated, interest has recently been developed in producing hybrid varieties as a considerable amount of heterosis has been demonstrated in the crop. Successful yield improvement depends on the variability present among the different genotypes and in-depth understanding of the underlying gene action and genetic architecture of traits related to yield. Line x tester mating design was used to determine the combining ability and gene action of traits, and therefore an experiment involving nine females and five male parents was undertaken at the National Semi-Arid Resources Research Institute (NaSARRI) and Ngetta Zonal Agricultural Research and Development Institute (NgeZARDI), during 2013 growing seasons to assess the combining ability and gene action of various traits. Results showed that mean squares across locations had high significant difference for all the traits recorded indicating that locations had effect on those traits. Variances for the males were higher than the variances for the females for all the traits except capsule width suggesting greater variability among the males than the females. Combined general combining ability (GCA) across locations showed that GCA for the lines and testers were significantly positive for a few traits. Specific combining ability (SCA) was only positively significant for days to flowering, number of capsules on branches, number of capsules on main stem, total number of capsules and capsule length. Baker’s ratio was high for most of the characters and medium for plant height, number of capsules on branches, number of capsules on main stem and capsule length. Coefficients of determination for narrow sense heritability (CD_nsh) were high for days to flowering, height of first branch and height of first capsule. Among the lines, Sesim 2, Ajimo A1-5, EM15-1-5, Ajimo A1-6//7029, Local 158//6022 and (Y-1//Local 158)-1-2-1 and among testers 4036-1-10-2 and SPS1438-1-6-4 were desirable for different traits.