Genomics-Assisted Analysis and Exploitation of Barley Diversity (ERA-PG 061)

在过去大约1万年的时间里，农作物通过驯化和选择性育种，从它们的野生祖先进化而来。这个过程为育种者捕获了许多有用的基因等位基因，但不幸的是，许多其他潜在有用的等位基因也在这个过程中丢失了。因此，有必要从野生植物中识别和招募新的等位基因，包括生态位适应、逆境耐受性和形态发育，以实现气候变化下可持续、环境友好的作物生产。通过建立广泛的基因组学信息和详细的表型分析，关联遗传学方法可能为实现这一目标提供了有力的途径。不幸的是，由于这些种群的连锁不平衡程度较低，在野生样本中进行全基因组关联作图需要数十万个基因连锁标记。我们提出了一种实验策略来克服这个问题，该策略利用了这样一个事实，即在不同的种群中，连锁不平衡以截然不同的速度衰减。我们的方法将以大麦为范例，研究关联作图在鉴定野生有用基因等位基因方面的有效性。我们的第二个目标是将这些新的有用基因等位基因引入到野生大麦（H. spontanum）种质资源与优良品种之间广泛杂交的高级回交育种计划中。这将使我们能够确定大麦育种计划中基于宽杂交的有用等位基因的鉴定和提取效率。我们的第三个主要项目目标是利用项目中获得的大量DNA和标记数据集来确定大麦的重要群体遗传参数。

Crop plants have evolved from their wild ancestors through domestication and selective breeding over approximately the last 10 000 years. This process has captured many useful gene alleles for breeders but, unfortunately, many other potentially useful alleles have also been lost during this process. There is therefore a need to identify and recruit new alleles from the wild, including niche adaptation, stress tolerance and morphology development for sustainable, environmentally benign crop production in the face of climate change. The association genetics approach potentially offers a powerful way to achieve this, by building upon extensive genomics information and detailed phenotypic analysis. Unfortunately, whole genome association mapping in wild samples requires hundreds of thousands of gene-linked markers, owing to the low levels of linkage disequilibrium in these populations. We propose an experimental strategy to overcome this problem, which exploits the fact that linkage disequilibrium decays at dramatically different rates in different populations. Our approach will use barley as a paradigm for investigating the effectiveness of association mapping in identifying useful gene alleles from the wild. Our second objective is to recruit these new useful gene alleles, into advanced back-cross breeding programs derived from wide crosses between wild barley (H. spontaneum) germplasm and elite cultivars. This will allow us to determine the efficiencies of identification and extraction of useful alleles in barley breeding programs based upon wide crosses. Our third major project objective is to use the huge DNA and marker data set obtained in the project to determine important population genetic parameters for barley.