Abstract
The objective of the present study was to investigate the magnitude of heterosis, inbreeding depression and combining ability in F2 population for seven quantitative traits in a 6 x 6 complete diallel cross involving six cultivars of spring wheat. F2 population suffered from considerable amount of inbreeding depression for all the traits suggesting that upward values in observed depression were attributable to factors like epistasis, linkage disequilibrium and abnormal segregation at meiosis due to higher ploidy level. Grain yield per plant displayed maximum observed and predicted inbreeding depression ranging from 25.25 to 88.71% and 10.16 to 19.85% respectively. Fair degree of mid parent heterosis in majority of the F2 hybrids cannoted that these hybrids could be exploited for commercial hybrid wheat development. General combining ability (GCA) indicated a large proportion of the total genetic variation for six out of seven effects. Specific combining ability (SCA) effects were significant for four of the seven traits indicating the presence of epistasis and dominant gene effects in these traits. Magnitude for GCAvariance was more pronounced than SCA variance for all the traits. Therefore selection has been advocated on the basis of GCA's of hybrids and breeding method should be designed to exploit both additive and non-additive gene actions. Key words: combining ability, heterosis, inbreeding depression, Triticum aestivum L
