Improvement of Open-Pollinated Spring Rapeseed (Brassica napus L.) Through Introgression of Genetic Diversity from Winter Rapeseed

The winter and spring types of oilseed Brassica napus L. belong to distinctly different genetic groups. Hence, it should be possible to use winter types for the improvement of spring type B. napus. We investigated the effect of introgression of alleles from winter type into open-pollinated Canadian spring B. napus cultivars. Crosses were made between two European winter rapeseed cultivars, Aviso and Tequila, a Canadian spring doubled-haploid (DH) line, A03-3NR, and two DH populations developed from F-2 plants. A total of 134 simple sequence repeat (SSR) markers from 19 linkage groups were evaluated on the three parents, of which 84 markers were polymorphic. Based on these markers, genetic similarity between the two winter parents was estimated to be 0 49, whereas it was only 0.27 between the spring and the two winter parents. Thirty-seven selected polymorphic markers were tested on the two DH populations, which detected a total of 94 alleles. Occurrence of the alleles from the winter parent ranged from 17.0 to 59.9% in DH population of Aviso x A03-3NR, whereas in the population of Tequila x A03-3NR it ranged from 13.8 to 50.0%. Estimates based on unweighted pair-group method with arithmetic mean (UPGMA) genetic similarity and principal coordinate analysis (PCoA) clearly depicted a group of DH lines falling close to the winter type. Seed yield in these DH populations was significantly higher than in the spring parent. Thus, introgression of winter germplasm into spring rapeseed is an important approach to broaden the genetic base of open-pollinated spring rapeseed.