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

通过育种拓宽甘蓝型油菜(Brassica napus L.，2n=38)的遗传基础，对该作物的持续改良具有重要意义。我的研究计划的长期目标是扩大我们对不同甘蓝型油菜基因库中存在的不同性状的等位基因变异的了解，包括甘蓝(CC，2n=18)，用于甘蓝型油菜的改良。然而，在拟议的研究中，我将重点关注甘蓝型油菜的开花和成熟度、种子产量性状和C基因组。由于草原省份的生长季节较短，开花和成熟期的提早对加拿大油菜籽很重要。过去几十年的育种努力在一定程度上改善了这种作物的早熟性；然而，到目前为止所达到的早熟性水平并不排除这种作物易受秋季霜冻的危险。到目前为止，利用油菜祖先种油菜(AA，2n=20)的早熟性来改善甘蓝型油菜的早熟性，但这往往是以种子产量为代价的。因此，在不对种子产量产生负面影响的情况下，需要进一步改进早熟性和确定对该性状有贡献的基因组区域。本研究基于甘蓝型油菜C基因组的开花时间基因和等位基因与甘蓝型油菜C基因组开花时间等位基因不同的假设，将这些等位基因导入甘蓝型油菜将增加花期等位基因的多样性，改善加拿大油菜的早熟性，并以以下目标为指导：(1)定位甘蓝早花等位基因。(中国羽衣甘蓝)，var.(花椰菜)，变种Capata(卷心菜)和var.为了解甘蓝型油菜早花等位基因在甘蓝型油菜遗传改良中的多样性程度，(Ii)根据油菜开花时间基因和春油菜品种中存在的等位基因，确定这些等位基因的独特性；(Iii)确定这些基因和等位基因对甘蓝型油菜种子产量的影响。从这项研究中获得的知识可以应用于加拿大早熟油菜品种的开发，而不会牺牲种子产量；这将确保作物在仲夏免受高温胁迫，在初秋免受霜冻损害。

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.