The genus Beta encompasses economically important root crops such as sugar and table beet. A Beta diversity set including the wild relative B. vulgaris ssp. maritima was grown in the field, and a large phenotypic diversity was observed. The genomes of 290 accessions were sequenced, and more than 10 million high-quality SNPs were employed to study genetic diversity. A genome-wide association study was performed, and marker-trait associations were found for nine phenotypic traits. The candidate gene within the M locus controlling monogermity on chromosome 4 was previously unknown. The most significant association for monogermity was identified at the end of chromosome 4. Within this region, a non-synonymous mutation within the zinc-finger domain of the WIP2 gene co-segregated with monogermity. This gene plays a regulatory role in AGL8/FUL in Arabidopsis. Intriguingly, commercial hybrids are in a heterozygous state at this position. Thus, the long-sought gene for monogermity was identified in this study. Red and yellow pigmentation due to betalain accumulation in shoots and roots is an important characteristic of table and leaf beets. The strongest associations were found upstream or downstream of two genes encoding Cytochrome P450 and anthocyanin MYB-like transcription factor proteins involved in betalain biosynthesis. Significant associations for Cercospora leaf spot resistance were identified on chromosomes 1, 2, 7, and 9. The associated regions harbor genes encoding proteins with leucine-rich repeats and nucleotide binding sites whose homologs are major constituents of plant-pathogen defense.

Flower development and plant architecture determine the efficiency of mechanized harvest and seed yield in Brassica napus. Although TERMINAL FLOWER 1 (AtTFL1) is a regulator of flower development in Arabidopsis thaliana, the function and regulatory mechanism of TFL1 orthologs in B. napus remains unclear. Six BnTFL1 paralogs in the genome of the B. napus inbred line ‘K407’ showed steadily increasing expression during vernalization. CRISPR/Cas-induced mutagenesis of up to four BnTFL1 paralogs resulted in early flowering and alteration of plant architecture, whereas seed yield was not altered in BnTFL1 single, double, or triple mutants. Six BnTFL1 paralogs, but not BnaA02.TFL1, showed an additive and conserved effect on regulating flowering time, total and terminal flower number, and plant architecture. BnaA10.TFL1 regulates flower development by interacting with BnaA08.FD through the protein BnaA05.GF14nu, resulting in the transcriptional repression of floral integrator and floral meristem identity genes. These findings about the regulatory network controlling flower development and plant architecture present a promising route to modifying these traits in B. napus.