Genetic variation for grain iron and zinc concentration in the US sorghum [Sorghum bicolor (L.) Moench] association panel

Iron (Fe) and zinc (Zn) are important nutritional traits that determine the cultivar value of grain sorghum [ Sorghum bicolor (L.) Moench]. The present study was undertaken to characterize the natural variation in landraces and accessions of sorghum association panel for grain Fe and Zn and to understand the nature of the association between grain Fe and Zn concentration and grain yield. Grain Fe and Zn were quantified from seeds harvested from rainfed and irrigated field experiments. The results indicated significant ( p < 0.05) variability in grain concentration of grain Fe and Zn among sorghum races and accessions. The highest concentrations for Fe and Zn were observed in elite breeding lines followed by the races durra and caudatum but with no significant impact between irrigated and rainfed growing environments. Trait association revealed a significant positive correlation between seed yield and iron ( r = 0.40) and zinc ( r = 0.13). Several accessions with desirable combinations of yield, iron, and zinc were identified. The accessions, SC1080 (90.5 mg kg −1 ) and RTx437 (37.8 mg kg −1 ), had the highest concentration of grain Fe and Zn, respectively. The accession SC1085 had a higher grain yield (50 g panicle −1 ) and high Fe concentration (80.3 mg kg −1 ), and Macia had a higher grain yield (43.0 g panicle −1 ) and high Zn concentration (29.5 mg kg −1 ).