Genomic analyses reveal the stepwise domestication and genetic mechanism of curd biogenesis in cauliflower

Cauliflower ( Brassica oleracea L. var. botrytis ) is a distinctive vegetable that supplies a nutrient-rich edible inflorescence meristem for the human diet. However, the genomic bases of its selective breeding have not been studied extensively. Herein, we present a high-quality reference genome assembly C-8 (V2) and a comprehensive genomic variation map consisting of 971 diverse accessions of cauliflower and its relatives. Genomic selection analysis and deep-mined divergences were used to explore a stepwise domestication process for cauliflower that initially evolved from broccoli (Curd-emergence and Curd-improvement), revealing that three MADS-box genes, CAULIFLOWER1 ( CAL1 ), CAL2 and FRUITFULL ( FUL2 ), could have essential roles during curd formation. Genome-wide association studies identified nine loci significantly associated with morphological and biological characters and demonstrated that a zinc-finger protein (BOB06G135460) positively regulates stem height in cauliflower. This study offers valuable genomic resources for better understanding the genetic bases of curd biogenesis and florescent development in crops. A high-quality reference genome assembly of cauliflower C-8 (V2) and genomic analyses of 971 diverse accessions and their relatives reveal the stepwise domestication and the genetic mechanism of curd biogenesis.