Objective In order to study the genetic mechanism of sweet corn pericarp thickness and select high-quality sweet corn varieties, the major genes and polygenes genetic analysis and QTL mapping of sweet corn pericarp thickness were carried out.

Method The sweet corn inbred lines T15 and T77 with large differences in pericarp thickness were selected to prepare hybrid combination (T77×T1). The F₂ population of the combination was used as the experimental material, the main genes and polygenes hybrid genetic method was used to analyze relevant parameters of the genetic model; Combined with the pericarp thickness and SSR genetic linkage map of each individual plant in F₂ population, QTL mapping of pericarp thickness in sweet corn was carried out by using composite interval mapping method.

Result It was found that A-1 was the optimal model for sweet corn pericarp thickness, that is, an additive and partially dominant genetic model controlled by a pair of major genes, and the heritability of major genes was 69.10%. There were three QTLs identified on chromosomes 5 and 8 respectively, which were related to pericarp thickness. Two QTLs were detected in region bin 5.04 of chromosome 5, which were located in the marker interval bnlg150-bnlg653 and bnlg653-bnlg1208 respectively, and the additive effect values were -2.39 and -3.01 respectively. The QTL located on chromosome 8 was in bin8.03-bin8.04, the marker interval was umc1741-bnlg2046, the additive effect value was -3.06, and the contribution rate to phenotype was 22.02%.

Conclusion The pericarp thickness of sweet corn is dominated by the effect of major genes. In breeding practice, genetic improvement and selection can be carried out in the early generation. The QTLs detected in this experiment can be used for molecular marker assisted selection and quality breeding.