The Indian Journal of Genetics and Plant Breeding

Gene effects were analyzed using means of number of tlllers-per-plant of 12 generations viz., both parents, F₁, F₂, first backcross generations (BC₁ and BC₂) second backcross generations (BC₁₁, BC₁₂, BC₂₁ and BC₂₂) along with BC₁₅ and BC₂₅ derived by selfing of BC₁ and BC₂ populations of three crosses involving six diverse cultlvars of durum wheat (Triticum durum Desf.). To determine the nature of gene actions governing number of tillers-perplant, generation mean analysis was used under normal and late sown environments. The ten-parameter model was adequate In ail the cases except in the cross Cocorit 71 x A-9-30-1 under late sown condition where the 3 parameter model was adequate. Epistatic effects, particularly trigenic types were predominant over additive and dominance effects under both normal and late sown environments. Duplicate epistasis was observed In two crosses under normal sown environment. Epistatic interactions particularly non-fixable types were the contributors to the significant and positive heterosis.