Degree of Dominance and Generation Mean Variance Analysisfor Biometrical Traits in Sesame (Sesamum indicum L.)
Abstract
The experiment was conducted with six generations derived from five inter varietal crosses
TMV 5 x KS99037(C1), TMV 5 x KS990812 (C2), TMV 5 x KS990813 (C3), TMV 5 x KS99153 (C4) and
TMV 5 x Cordebergea (C5) involving six genotypes of sesame to study the components of
variances and degree of dominance for different traits. The observations on days to first
flowering, days to maturity, plant height, number of primary branches, number of capsules
per plant, capsule length, number of seeds per capsule, 100 seed weight and seed yield per
plant were recorded for the selected individual plants. The variances estimated from different
generations were partitioned into different genetic components of variation. The degree of
dominance was greater than unity in TMV 5 x KS99037 for days to maturity, in TMV 5 x KS990812
for days to first flowering, in TMV 5 x KS990813 for days to first flowering and days to maturity,
in TMV 5 x Cordebergea for number of seeds per capsule which showed over dominance for
the respective traits. Hence, it is suggested for adoption of heterosis breeding for these
crosses in sesame. The cross TMV 5 x KS99037 for days to first flowering, number of branches
per plant and oil content and TMV 5 x KS990813 for plant height and number of capsules per
plant showed partial dominance for the respective traits. The recombination breeding followed
by selection in the later generation will improve the respective traits. The traits, plant height,
number of capsules per plant and 100 seed weight were largely controlled by both additive
and dominance variance. The pedigree or recombination breeding followed by selection in
later generations would improve these characters. The environmental variance for the
characters days to maturity, number of branches per plant, number of capsules per plant,
capsule length, number of seeds per capsule and 100 seed weight revealed that environment
plays an important role for the expression of these traits.
Keywords: Sesame, gene action, components of variance, additive and dominance
