Genetic variability for grain iron and zinc content in cultivars, breeding lines and selected germplasm accessions of sorghum [Sorghum bicolor (L.) Moench]

Sorghum is an important cereal grain consumed in semiarid tropics of Asia and Africa, which is nutritionally superior with more micronutrient content compared to rice and wheat. Grains of adapted cultivars, parental lines, advance breeding lines and selected germplasm accessions of sorghum were characterized for the levels of iron (Fe) and zinc (Zn). Considerable variability for grain Fe and Zn contents was observed. In general, germplasm lines had higher values for Fe and Zn compared to cultivars and breeding lines. The mean values were found to be less repetitive upon reanalysis of selected genotypes. Hence, the entire set was reanalyzed which again established sufficient variability for grain Fe (12.1–83.4 mg/kg) and Zn (6.3–51.4 mg/kg) contents among the test genotypes as well as high heritability. Significant positive association between grain Fe and Zn content was observed (r = 0.2 – 0.5, p < 0.05) indicating possibility of simultaneous improvement of both micronutrients.The availability of high variability for grain Fe and Zn contents among the genotypes tested holds promise for grain micronutrient enrichment through breeding programmes.