Relative efficiency of biparental mating, single capsule descent, selected bulk and random bulk selections in sesame (Sesamum indicum L.)

A study was undertaken in sesame (Sesamum indicum L.) to assess the relative efficiency of biparental mating and three selection procedures in realising greater variability with desirable recombinants using F2 of two crosses viz. TMV 3 × IS 387-2 and KS 95010 × EC 343402. These F2 populations were advanced to F3 following intermating [biparental mating (BIP)] and selfing [selected bulk (SB), random bulk (RB) and single capsule descent (SCD)] approaches. The four populations thus developed in each of the two crosses were then evaluated for three earliness traits and three productive traits. BIP proved its superiority over selfing by registering high mean values in desirable direction for all the traits. Among the selfing series SCD was found superior followed by RB over SB. When compared to the F3 selfed populations, high genetic variability combined with high heritability and genetic advance was noticed in BIP of both the crosses for most of the earliness traits, except days to maturity while SCD and RB populations showed low estimates for the variability parameters. Correlation studies indicated that the undesirable strong positive associations that existed among the traits related with duration and productivity in F3 populations were converted into insignificant associations in BIP of both the crosses, thereby offering a great scope of selecting recombinants combining both earliness and productivity in BIP progenies. This possibility was limited in F3 selfed populations. Further it was inferred that in the selfed populations of both the crosses, the traits related with duration had significant positive association with seed yield primarily because of tight linkage between duration and capsule number. This tight linkage was broken in BIP as observed by the change in magnitude and direction of association in BIPs. This was attributed to breakage of undesirable linkage by forced recombinations induced by biparental mating.