Inheritance studies on grain iron and zinc concentration and agronomic traits in sorghum [Sorghum bicolor (L.) Moench]

Sorghum is a major staple globally and biofortifying sorghum with increased grain iron and zinc complements ongoing efforts to combat micronutrient malnutrition. Limited information available on the nature and magnitude of gene effects for grain iron and zinc. So generation mean analysis was done using four crosses, ICSB 52 x IS 13211, ICSB 52 x SPV 1359, IS 20843 x IS 2248 and IS 2248 x IS 20843. Six generations, P1, P2, F1, F2, B5 and B2, were generated for each of these crosses which were evaluated during the postrainy season 2012-13. The mean sum of squares due to generations were significant for days to flowering, plant height, grain yield/ plant, 100-grain weight, and grain Fe and Zn. Generation mean studies revealed the presence of both additive and dominant gene interactions in inheritance of agronomic traits. Duplicative epistasis was observed for days to flowering, plant height, grain yield/plant, 100-grain weight, and grain Zn with a predominance of dominant gene action in inheritance of these traits. Panicle length, panicle width, and grain Fe showed both additive and dominance gene effects, with higher magnitude of dominance. This information can be utilized in developing sorghum lines with high grain Fe and Zn.