Heterosis and inbreeding depression in the inheritance of grain yield and its components in wheat (Triticum aestivum)

The experiment was carried out during rabi season 2007–08 at Deoria(Uttar Pradesh), India. Forty five F_1s, 45F_2S and grain yield and its components in a diallel set derived from 10 promising lines were tested in a randomized block design with three replications in wheat [Triticum aestivum (L.) emend. Fiori & Paol.]. The study revealed that 26 crosses of positive and significant values and 16 combinations of negative and significant values for inbreeding depression (26.39 to 29.80%) were independently associated with heterosis. The heterosis over economic parent for grain yield plant⁻¹ (−37.53 to 31.26%) exhibited negative performance in all the combinations, except PBW 343 x K 9107, K 9107 x K88, K9107 x K8962, K88 x K8962, K8962 x K9533, K8962 x KRL1-4 and HUW 234 x K816, whereas non-significant heterosis were observed in PBW 343 x K9533, PBW 343 x KRL1-4, K88 x HP1633 and K9533 x K7903 crosses in first filial generation. In breeding depression of this trait (range from -15.19 to 65.67%) exhibited mostly positive and significant performance in all the combinations indicate the prevalence of non-additive gene effects due to genetic variability in the population.