Exploitation of genetic variation to enhance grain nutrient contents in bread wheat through conventional and molecular approaches

Considering the importance of wheat as a staple food crop and its contribution to human nutrition, it is important to continuously screen wheat germplasm for higher grain nutrients especially Fe and Zn and estimate their genetic diversity. Fifty wheat genotypes were field tested in Randomized Complete Block Design (RCBD) and data was taken for grain Fe and Zn contents and important agronomic traits. The genotypes were subjected to molecular screening with SSR markers designed from ESTs expressed for grain Fe & Zn contents and gene specific primers previously reported for marker assisted selection. Results revealed that spike length, 1000 grain weight, and grain Fe and Zn contents showed highly significant differences among genotypes (p-value = 0.01). The genotypes LLR-23 was identified for highest grain Fe contents (2.49 mg/kg) followed by GA-2002 (1.58 mg/kg), 28SAWSN-3072 (1.45 mg/kg), LLR-34 (1.45 mg/kg) and ETAD-164 (1.38 mg/kg) whereas, highest grain Zn contents were found in LLR-23 (1.97 mg/kg) followed by GA-2002 (1.64 mg/kg) and LLR-34 (1.52 mg/kg). The presence of NAM-B1 gene, responsible for higher grain Fe and Zn contents was confirmed in these genotypes by the gene specific primers NAM-B1 (a), NAM-B1 (c), NAM-B1 (d) and NAM-B2 on chromosome 2B. The superior wheat genotypes enriched in grain Fe and Zn contents, and validated by the presence of NAM genes in this study is important for future breeding programs aimed at developing Fe and Zn biofortified wheat.