Extending the rapeseed genepool with resynthesized Brassica napus L. I: Genetic diversity

Resynthesized Brassica napus L. could be employed to increase the genetic variation in the narrow oilseed rape genepool and to establish a genetically distant genepool for hybrid breeding. One important criterion for selecting appropriate resynthesized lines is their genetic distance to adapted breeding material. In this study we estimated the genetic distances in a wide collection of 142 resynthesized lines and 57 winter and spring rapeseed cultivars from Europe, North America and Asia using RFLP marker data. The highest in-group genetic distance (0.36) was observed in 142 resynthesized lines compared to 0.21 in winter, 0.23 in summer, and 0.28 in Asian genotypes. The group of adapted breeding material clustered into three groups of winter-, spring-type, and Asian genotypes. Resynthesized lines did not form distinct subgroups in the cluster analysis, but large differences were revealed in the genetic distance of resynthesized lines to the adapted winter oilseed rape genepool. The highest distance to winter oilseed rape was found in resynthesized lines with parental lines from the Asian genepool as B. oleracea convar. botrytis var. alboglabra (Bail.) Sun or B. rapa ssp. chinensis (L.) Hanelt.