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It is interesting to note that sca effects of top crosses in our study and gca effects of their parents indicated that majority of the good specific cross combinations was the result of good x good or poor x poor combinations. Thus, it was evident that good cross combination is not necessarily the result of good x good combination of parents, rather it might occur from poor x poor combinations as well. A number of studies also refer to such a situation (Chaudhary and Paroda 1979; Sheikh et al. 2000; Singh 2002). High sca effects of good x good combiners reflect additive x additive type of gene interaction and that superiority of favorable genes contributed by the parents. While those involving good x poor or poor x poor general combiners indicated the interaction of additive x dominance or dominance x dominance, respectively. Biparental progeny selection suggested by Andrus (1963) could be used to get some transgressive segregants from crosses good x good or good x average combinations for genetic improvement of the traits.

Present study confirmed that additive as well as non-additive gene effects controlled the expression of most of the characters under all the sowing dates. Hence, non-conventional breeding methods such as biparental mating (Joshi and Dhawan 1966) or diallel selective mating (Jensen 1970) in addition to conventional breeding methods were suggested for amelioration of grain yield through manipulating its component characters.

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