Effect of Mutagen and Biparental Mating in Self-Fertilizing Species, Triticum Aestivum L. Em. Thell

Additive and dominance genetic variances were estimated by NCD II (normal and mutagen-treated populations) and NCD III (normal population) biparental mating designs for protein and tryptophan contents in wheat. The NCD III seemed relatively more efficient than NCD II. Both additive and dominance genetic variances were important for controlling the traits. However, the magnitude of additive component was much higher than that of dominance component. The estimates of the additive genetic variances increased in the mutagen-treated populations, whereas the dominance genetic variance decreased for both the traits. The means of the NCD II and NCD III progenies (BIPs) were higher than those of the F2 and F3 selfs. The mean performance of both traits increased in the second cycle of biparental matings over the first cycle. Thus, to exploit both additive and nonadditive genetic variances, to break undesirable linkages, and to release latent genetic variability and ultimately to improve the population, recurrent biparental matings in the early generations have been suggested.