Due to the relatively brief history of sugar beet (Beta vulgaris ssp. vulgaris) domestication, our understanding of the genomic diversity and functional genes associated with sugar beet cultivars is limited, resulting in slow breeding progress. To address this issue, a total of 306 germplasm materials of major cultivars or major breeding lines from China, USA and Europe were selected for genome resequencing. We investigated the population structure, genetic diversity, and performed selective scanning of regions to identify genes six novel genes associated with important agronomic traits. This study identified candidate genes DFAX2 and P5CS associated with skin roughness, candidate genes FRO5, GL24 and PPR91 associated with root yield and sugar yield, and pleiotropic gene POLX associated with flourishing growth vigour, plant height, crown size, flesh coarseness and sugar yield at the same time were identified. In addition, we constructed a gene PPI network map and a phenotype-gene network map, which provide valuable information for identifying and characterizing functional genes affecting agronomic traits in sugar beet. Overall, our study can shed light on the future improvement of sugar beet agronomic traits at the molecular level.