Abstract: In this study, a 56K SNP chip was used to evaluate the structure of natural population in 100 sweet corn inbred lines and to locate the seed nutritional quality with association mapping. The results showed that 100 inbred lines were divided into two subgroups, the subgroup 1 contained 92 germplasms and the subgroup 2 contained 8 germplasms. PIC values of 37 297 high-quality SNPs with uniform genome coverage were concentrated at 0.19, and the variation of gene diversity was concentrated between 0.36 and 0.38. The starch content of seed was in 53.91%-73.70%, the protein content was in 8.96%-18.01% and the fat content was in 5.53%-18.50%. There were 14, 15 and 20 SNP molecular markers revealed by GLM-Q model for starch content, protein content and fat content in sweet corn seeds which could explain 3.45%-51.69% of phenotypic variation. At -log₁₀P>3.50 level, the qSTA-3-1 that was on Affx-115329496 of No.3 chromosome could explain 20.90% of starch variation. qPRO-1-1 and qPRO-9-2 were the significant association locus with protein content of sweet corn, which were on the Affx-91181539 of No.1 chromosome and on the Affx-115333989 of No.9 chromosome. qFAT-5-1 on Affx-91137282 of No.5 chromosome was associated with fat content of sweet corn.

Key words: sweet corn, seed, nutritional quality, genome-wide association