Genome-wide association study identifies the genetic basis of key agronomic traits in 207 sugar beet accessions

Sugar beet (Beta vulgaris) has emerged as one of the two primary crops, alongside sugarcane, for global sugar production. Comprehensively understanding sucrose synthesis, transport, and accumulation in sugar beet holds great significance for enhancing sugar production. In this study, we collected a diverse set of 269 sugar beet accessions worldwide and measured 12 phenotypes, comprising biomass, soluble sugar content, and 10 taproot-related traits. We re-sequenced 207 accessions to explore genetic diversity and population structure. Then we employed a genome-wide association study (GWAS) and RNA-seq to identify single-nucleotide polymorphisms and genes associated with natural phenotypic variations. Our findings revealed a panel of genes potentially regulating biomass and sugar accumulation, notably the dual-role gene UDP-glucose 4-epimerase, which genetically balances sugar accumulation and cell wall synthesis. In summary, this study provides a foundation for molecular breeding in sugar beet.