Exploration into Natural Variation Genes Associated with Determinate and Capitulum-like Inflorescence in Brassica napus

Brassica napus is a globally important vegetable and oil crop. The research is meaningful for the yield and plant architecture of B. napus. In this study, one natural mutant line with determinate and capitulum-like inflorescence was chosen for further study. Genetic analysis indicated that the segregation patterns of inflorescences in the F(2) populations supported a digenic inheritance model, which was further approved via the BSA-Seq technique. The BSA-Seq method detected two QTL regions on C02 (14.27–18.41 Mb) and C06 (32.98–33.68 Mb) for the genetic control of determinate inflorescences in MT plants. In addition, the expression profile in MT compared with WT was analyzed, and a total of 133 candidate genes for regulating the flower development (75 genes, 56.4%), shoot meristem development (29 genes, 21.8%), and inflorescence meristem development (13 genes, 9.8%) were identified. Then one joint analysis combing BSA-Seq and RNA-Seq identified two candidate genes of BnaTFL1 and BnaAP1 for regulating the MT phenotype. Furthermore, the potential utilization of the MT plants was also discussed.