Genetic mapping of quantitative trait loci associated with grain iron and zinc concentration in maize ( Zea mays L.)

Iron (Fe) and Zinc (Zn) are essential micronutrients that play a crucial role in a wide range of metabolic processes in living organisms and are indispensable for maintaining normal growth, development and metabolic homeostasis. In the present study, a population of 120 recombinant inbred lines (RILs) was utilized for quantitative trait loci (QTL) analysis to assess grain iron (Fe) and zinc (Zn) content in maize across 2 growing seasons, using a total of 105 simple sequence repeat (SSR) markers. Composite interval mapping (CIM) performed using QTL Cartographer software identified one QTL for grain Fe content (qfe4.1) located on chromosome 4 with the nearest marker umc1390. For grain Zn content, three QTLs were detected: qzn4.1 (linked to umc1060), qzn4.2 (linked to umc1232) and qzn6.1 (linked to umc1753). Among these, qfe4.1 and qzn4.1 were consistently detected across both seasons, whereas qzn4.2 and qzn6.1 were identified in only one season and are therefore considered season‐specific QTLs. The co‐localization of qfe4.1 and qzn4.1 on chromosome 4 suggests that this genomic region may influence both Fe and Zn accumulation. However, further validation is required to confirm a common genetic basis. Overall, QTLs associated with grain Fe and Zn content were identified on chromosomes 4 and 6. These results provide a theoretical foundation for enhancing the iron and zinc content of maize lines through marker‐assisted selection.