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

通过选育拓宽甘蓝型油菜（Brassica napus L.， AACC, 2n = 38）的遗传基础，对甘蓝型油菜的持续改良具有重要意义。我的研究项目的长期目标是扩展我们对甘蓝不同基因库中不同性状等位基因变异的认识，包括甘蓝（CC, 2n = 18），以改进油菜。然而，在拟进行的研究中，我将重点研究甘蓝型油菜的早熟性、早熟性和种子产量性状以及甘蓝型油菜的C基因组。由于加拿大大草原省份的生长季节较短，因此早开花和成熟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提高了这种作物的早熟性；然而，到目前为止所取得的早期水平并不排除这种作物易受秋季霜冻危险的影响。迄今为止，利用B. rapa （AA, 2n = 20）祖先物种的早发性来提高甘蓝型油菜的早发性；然而，这往往是以牺牲种子产量为代价的。因此，需要进一步提高该性状的早期性和鉴定基因组区域，而不会对种子产量产生负面影响。未来5年的研究将基于甘蓝C基因组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，这些等位基因在甘蓝型油菜中的渗入将增加开花时间等位基因的多样性，提高加拿大油菜的早熟性，其指导目标如下：(1)绘制正在向油菜中渗透的甘蓝早花等位基因var. alboglabra（芥蓝）、botrytis（花椰菜）、var. capitata（白菜）和var. italica（西兰花）的等位基因图谱，了解油菜基因库中早花等位基因的多样性程度，为油菜改良提供依据；（ii）确定这些等位基因在春季甘蓝型油菜开花时间基因和等位基因背景下的独特性；(3)确定这些基因和等位基因对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，而不牺牲种子产量；这将确保作物免受盛夏的高温胁迫和初秋的霜冻损害。

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.