Identification and Fine Mapping of the Candidate Gene Controlling Multi-Inflorescence in Brassica napus

As a desirable agricultural trait, multi-inflorescence (MI) fulfills the requirement of mechanized harvesting and yield increase in rapeseed (Brassica napus L.). However, the genetic mechanism underlying the multi-inflorescence trait remain poorly understood. We previously identified a difference of one pair of dominant genes between the two mapping parental materials. In this study, phenotype and expression analysis indicated that the imbalance of the CLAVATA (CLV)-WUSCHEL (WUS) feedback loop may contribute to the abnormal development of the shoot apical meristem (SAM). BnaMI was fine-mapped to a 55 kb genomic region combining with genotype and phenotype of 5768 BCF(1) individuals using a traditional mapping approach. Through comparative and expression analyses, combined with the annotation in Arabidopsis, five genes in this interval were identified as candidate genes. The present findings may provide assistance in functional analysis of the mechanism associated with multi-inflorescence and yield increase in rapeseed.