Paper Title
Study of Allelic Constitution of the Parents in Wheat

India has great scope in increasing in aestivum wheat production by (I) breeding still more efficient plant types adaptable to wide range of ecological conditions, for broad spectrum of disease and pest resistance, better nutritive quality and responsiveness to inputs, (II) standardizing the breeding procedures for the exploitation of heterosis to economic advantage in this crop (III) increasing yield per unit area with the adoption of suitable transfer of technology (IV) bringing more areas under wheat cultivation, (V) bringing break-through in the yield levels through improvement in harvest index, physiological traits and finally (vi) by breeding wheat through multiple crosses, spring x winter crosses, recurrent selection, multiple resistance and multi-lines. The improvement in the existing breeding methodologies cannot be overlooked in this aspect. In self-pollinated crop like wheat, heterosis as such may not be of much value unless it is possible to exploit it through the development of hybrid varieties. Alternatively, it should be fixable so that better segregants could be selected in advanced segregating generations. It is quite evident from the available literature that heterosis is highly influenced by environment. Directional heterosis and its fixation, therefore, appears to be distinct possibility.The experimental material of present investigation comprised of eight genetically diverse genotypes of bread wheat, Triticum aestivum (L.) viz. LOK- 1(Unnath), HD 2334, HUW 309, HUW 325, VL 641, HD 2189, CPAN 1548 and DL 230-7 crossed in half diallel fashion to develop 28 crosses. 8 parents, 28 F 1 , 28 F 2 were grown together in randomized complete block design under late sown with fully irrigated (E1) , late sown with partially irrigated (E2) conditions during winter season of 1994-95 and were evaluated for various quality and yield traits.In the present study, graphical analysis was carried out to know the allelic constitution (dominant or recessive) of the parents involved in diallel cross, and the presence or absence of epistasis. Graphical analysis also helps to know the average degree of dominance operative in the inheritance of a trait in question. It may be partial (when F 1 nearer to mid value), complete (only one character appears ) and over dominance (one character appears greatly ). Results of the analysis revealed that the slope of regression line differed significantly from unity for all the characters in both the situations. It indicates the presence of interalletic interaction. In graphical analysis, it was interesting to note that the parent Lok-1 and HUW 309 possessed more dominant genes for most of the traits under study, whereas, parent VL 641 and DL 230-7 had more recessive genes for most of the traits. Rest of the parents had balanced proportion of dominant and recessive genes. These results further revealed that allelic constitution of parents was influenced by the environmental fluctuations. These results are in general agreement with the findings of Rawat (1988), Menon and Sharma ( 1997), Singh et al. (1998).