Diallel crosses involving 8 wheat cultivars were used to determine the type of genetic effects and to estimate the general arid specific combining abilities for biological yield and harvest index. parents and F1’s were evaluated in a completely randomized design with 4 replications in the greenhouse. Data were analized according to methods of Hallauer and Miranda and also model 1 of Grriffing’s method 4 for diallel crosses. The jinks-Hayman analysis was used to estimate the genetic parameters for harvest index.
Significant differences occurred between parental lines and between crosses for both traits and also grain yield (previously reported). The GCA,SCA, and average heterosis (F1’s vs parents) mean squares indicated that both additive and non-additive genetic effects contributed to the expression of these traits, but the contribution of non-additive effects was of more importance. The graphic interpretation of jinks— Hayman analysis revealed the presence of overdominance for harvest index, but considering the assumptions of the model, it seems to be apparent or peseudo-overdominace. Our results revealled the effectivness of selection for harvest index, specially among the progenies of crosses between Lordegan, Chadeghan, Natanz, and Moghan-2 whith the other parental lines studied
)