Delineating genetic inheritance and nonallelic genic interactions for grain iron and zinc concentration, yield and its attributes by generation mean analysis in pearl millet [Pennisetum glaucum (L.) R. Br.]

Pearl millet is a major staple cereal crop worldwide and genetic biofortification with enhanced grain iron (Fe) and zinc (Zn) concentrations are ongoing efforts to combat micronutrient malnutrition. There is limited information on the nature and magnitude of gene action for Fe and Zn densities, yield and its component traits in pearl millet. Therefore, generation mean analysis was carried out with six basic generations viz., P-1, P-2, F-1, F-2, BC1 and BC2 derived from nine crosses using 18 parental lines of diverse pedigree. Analysis of variance revealed that genotypes were significant for days to flowering, days to maturity, panicle length, panicle girth, plant height, number of productive tillers per plant, grain yield per plant, 1000 grain weight, grain iron content and grain zinc content in all the crosses while, non significant for days to maturity and 1000 grain weight in crosses J 2340 x 30291 and ICMB 10444 x ICMB 97222, respectively. Generation mean analysis studies revealed that inheritance of grain yield per plant and contributing traits were governed by additive, dominance and varied types of nonallelic interactions. The additive and varied nonallelic interactions were observed in few crosses for days to maturity, plant height, panicle girth, 1000 grain weight and grain iron content. Similarly, dominance and varied types of nonallelic interactions were present in limited crosses for days to flowering, days to maturity, plant height, number of productive tillers per plant, panicle length and panicle girth. The dominance gene action was observed in cross J 2372 x 30610 for number of productive tillers per plant and J 2454 x 30348 for panicle length while, additive gene action was exhibited in cross 30727 x J 2523 for days to maturity and J 2340 x 30291 for panicle length in pearl millet. Presence of duplicate epistasis in most of the crosses for all the traits except number of productive tillers per plant indicated prevalence of greater genetic diversity. While, complementary epistasis was restricted to limited crosses for days to flowering, plant height, number of productive tillers per plant, panicle length and grain yield per plant. For grain Fe and Zn content varied nonallellic interactions in combination with additive and dominance gene actions played a major role in influencing the trait. However, nonallelic gene interactions with only additive (d) gene actions played a major role in genetic control of grain iron content in crosses J 2340 x 30291, 30127 x J 2556, ICMB 10444 x ICMB 97222 and 30843 x ICMB 98222. Moreover, one cross 30725 x ICMB 05333 showed only additive gene effect and additive x dominance component of genic interaction for grain zinc content. This information can be utilized in developing pearl millet lines with high grain Fe and Zn content.