A fully phased, chromosome-scale genome of sugar beet line FC309 enables the discovery of Fusarium Yellows resistance QTL

Sugar beet ( Beta vulgaris L.) is a global source for table sugar and animal fodder. Here we report a highly contiguous and haplotype phased genome assembly and annotation for sugar beet line FC309. Both assembled haplomes for FC309 represent the largest and most contiguous assembled beet genomes reported to date, as well as gene annotations sets that capture over 1500 additional protein-coding loci compared to prior beet genome annotations. These new genomic resources were used to identify novel quantitative trait loci (QTL) for Fusarium Yellows resistance from the FC309 genetic background using an F2 mapping-by-sequencing approach. The highest QTL signals were detected on Chromosome 3, spanning approximately 10 Mbp in both haplomes. A parallel transcriptome profiling experiment identified candidate genes within the Chromosome 3 QTL with plausible roles in disease response, including NBS-LRR genes with expression trends suggestive of their role as causal resistance genes. Collectively, the genomic resources for FC309 presented here be foundational tool for comparative genomics, mapping other traits in the FC309 background, and as a reference genome for other beet studies due to its contiguity, completeness, and high-quality gene annotations. ### Competing Interest Statement The authors have declared no competing interest.