ASHS 2024 Conference

Spinach (Spinacia oleracea L.) stands as a globally significant vegetable celebrated for its rich array of nutritional and health-promoting compounds. Bolting, a crucial trait in spinach cultivation across diverse seasons and regions, is heavily influenced by photoperiod sensitivity. The premature induction of bolting in spinach due to extended daylight exposure can render the plant unsuitable for market. This study aimed to conduct a comprehensive genome-wide association study (GWAS) to pinpoint single nucleotide polymorphism (SNP) markers associated with late bolting in spinach and to perform genomic prediction for this trait. GWAS was executed on a panel of 295 USDA spinach germplasm accessions, utilizing 16,563 SNPs derived from whole-genome resequencing. Various statistical models, including GLM, MLM, FarmCPU, and BLINK, were deployed in the analysis using the GAPIT 3 tool. A significant quantitative trait locus (QTL) region on chromosome 6 was identified, with three SNP markers — SOVchr6_13545609, SOVchr6_13545882, and SOVchr6_13545887 — located between 13,545,609 bp and 13,545,887 bp, demonstrating robust associations with late bolting. Additionally, the gene SOV6g004620, encoding a TTF-type domain-containing protein and situated at 13,566,721 bp to 13,567,164 bp on chromosome 6, emerged as a potential candidate for regulating bolting. Genomic prediction exhibited a high prediction ability (GA) with an r value of 0.85. The identified SNP markers and GA metrics present valuable tools for breeders to selectively cultivate late-bolting spinach plants and lines through marker-assisted selection (MAS) and genomic selection (GS), thereby facilitating enhanced spinach breeding endeavors.