Exploration of the Brassica gene pools for the improvement of spring Brassica napus L. canola

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Broadening the genetic base of Brassica napus L. (AACC, 2n = 38) canola through breeding is important for continued improvement of this crop. The long-term goal of my research program is to extend our knowledge on the allelic variation for different traits present in different Brassica gene pools, including B. oleracea (CC, 2n = 18), for the improvement of B. napus canola. However, in the proposed research, I will focus on the earliness of flowering and maturity and seed yield traits and on the C genome of B. napus. Earliness of flowering and maturity are important for Canadian canola due to the short growing season in the Prairie Provinces. Breeding efforts in the last decades have improved the earliness in this crop to some extent; however, the level of earliness achieved so far does not exclude the predisposition of this crop to the danger of fall frost. To date, the earliness of the progenitor species B. rapa (AA, 2n = 20) has been exploited to improve the earliness in B. napus; however, this is often achieved at the cost of seed yield. Therefore, further improvement of earliness and identification of the genomic regions that contribute to the trait without negatively affecting seed yield are needed. The research to be carried out over the next five years is based on the hypothesis that flowering time genes and alleles of the C genome of B. oleracea are different from the C genome flowering time alleles of B. napus and introgression of these alleles in B. napus will increase diversity of flowering time alleles and will improve the earliness in Canadian canola, and is guided by the following objectives: (i) map the early-flowering alleles of B. oleracea var. alboglabra (Chinese kale), var. botrytis (cauliflower), var. capitata (cabbage) and var. italica (broccoli), which are being introgressed into B. napus canola, to understand the extent of diversity for early-flowering alleles exists in the B. oleracea gene pool for the improvement of B. napus canola; (ii) determine the uniqueness of these alleles in the context of the flowering time genes and alleles present in spring B. napus cultivars; and (iii) determine the effect of these genes and alleles on seed yield in B. napus canola. The knowledge gained from this research can be applied to the development of early maturing canola cultivars for Canada without sacrifice for seed yield; this will secure the crop from heat stress in mid-summer and from frost damage in early fall.