“…In contrast, a series of important milestones have been achieved in the CR breeding of B. rapa , owing to the advantages of their quality traits or the high contribution rate of quantitative trait loci (QTLs). So far, many CR loci have been identified in B. rapa , B. nigra and turnip, including CRa [ 15 , 16 ], CRb [ 17 ], CRc [ 18 ], CRd [ 5 ], CRk [ 18 ], CRq [ 19 ], CRs [ 20 ], Crr1a [ 21 ], Crr2 [ 22 ], Crr3 [ 23 ], Crr4 [ 22 ], CrrA5 [ 24 ], Rcr1 [ 25 ], Rcr2 [ 26 ], Rcr3 [ 27 ], Rcr6 [ 28 ], PbBa8.1 [ 29 ], BraA.Pb.8.4 [ 30 ], BraA.CR.a [ 31 ], and BraA.CR.b [ 31 ] . These studies have promoted the understanding of the molecular mechanism of CR, and the development of molecular markers that are closely linked to CR genes have accelerated the breeding of CR varieties.…”