Combining Ability Studies for Seed Yield, Its Component Characters and Oil Content in Toria

The nature and magnitude of combining ability effects were studied for seed yield, its components and oil content in toria (Brassica campestris spp oleifera). Analysis of variance for combining ability revealed that mean squares due to gca and sca were significant for all the characters. This indicates that both additive and non additive gene effects were important in the expression of these characters. The mean degree of dominance (?2sca/?2gca) was quite high for seed yield per plant, plant height, number of siliquae on main shoot and primary branches, indicating the involvement of non-additive gene effects in controlling the inheritance of these traits. PBT 37 was good combiner for seed yield per plant, number of siliquae on main shoot and primary branches per plant while, HOCT-1 exhibited highly significant gca effects for Per cent Disease Index (PDI) of Alternaria blight, 1000 seed weight and oil content. The crosses HOCT-1 x PBT 226 and PBT 97 x PBT 37 showed maximum significant sca effect for seed yield, plant height and seed boldness. As both additive and non-additive gene effects are present, breeding strategies that exploit both types of gene actions such as biparental mating approach and reciprocal selections should be followed for the genetic improvement of seed yield and other traits and this will also give further opportunity for substantial release of locked up genetic variability.