Objective In order to exploit and utilize high vitamin sweet corn germplasm resources, QTL mapping of vitamin C content in sweet corn was carried out.

Method The inbred lines T77 (high VC) and T15 (low VC), which have significant differences in vitamin C content, were used as parents to prepare the hybrid combination T77×T15, and the combination F₂ was used as mapping population to construct SSR molecular marker genetic linkage map. Combined with the vitamin C content of each individual ear in F₂, QTL mapping of vitamin C content in sweet corn was carried out by using compound interval mapping method.

Result Five related QTL were detected, which were located on chromosome 2, 3 and 6. One vitamin C QTL (qVC-ch.2-1) was detected in the bin2.04-2.05 region of chromosome 2, with an additive effect value of 2.23, which could explain 17.16% of phenotypic variation. Two QTL for vitamin C content (qvc-ch.3-1 and qVC-ch.3-2) were detected on chromosome 3, which were located in bin3.00-3.04 and bin3.06-3.07 respectively, with additive effect values of 1.17 and 1.40, and phenotypic contribution rates of 6.64% and 4.15% respectively. Two QTL for vitamin C content (qvc-ch.6-1 and qVC-ch.6-2) were detected on chromosome 6, which were located in 6.05 and 6.056.06 regions, with additive effects value of 0.43 and 1.83, and contribution rates of 6.59% and 20.87%, respectively.

Conclusion The study on QTL mapping of vitamin C content would provide a theoretical basis for breeding sweet corn varieties with high quality and nutrition in breeding practice.