YIA-PGR: Molecular Evolutionary Genetics of Crop and Weed Responses to Crowding

野生物种的驯化以各种特征的变化为特征，包括植物结构、果实和种子形态、果实扩散和发育事件的时间。这些变化是人类为增加产量而进行选择的结果。在这方面，环境反应的变化也很重要。例如，更高的种植密度可以提高许多作物的产量，但密度受到对拥挤的发育反应的限制，在这种反应中，开花时间减少，结构器官的相对分配增加，代价是叶片、根和果实生产等农艺性状的损失。无论选择哪种作物，农业杂草都表现出戏剧性的补偿性进化，这种进化增加了杂草的适合性，但代价是作物生产力下降。比较遗传学方法和基因组学工具为研究拥挤表型反应的遗传基础提供了一种手段。该研究项目的重点是甘蓝型油菜的拥挤反应。除了驯化的品种外，在农田和受干扰的杂草地点都会出现归化种群。因此，该系统适合于研究驯化期间的目标基因座和杂草物种对农业环境的潜在适应。这项研究利用现有的基因组工具来研究农业和自然环境中竞争性反应的遗传基础。具体目标包括1)确定影响田间环境中竞争能力的适合度和性状的遗传决定因素(称为数量性状基因座或QTL)，2)利用受控光环境来确定对特定环境线索的反应重要的QTL，3)量化QTL上的进化反应(以等位基因频率变化衡量)，确定农业和干扰地点对竞争的适合度和表型反应，以及4)克隆对竞争能力重要的性状的QTL，目的是确定作物改良的遗传目标和农业杂草的潜在进化变化。这项实验研究不仅将现有的基因组工具应用于进化研究，还将开发和分发更多的遗传资源，以便传播给其他研究人员。这一结果将对作物改良和对杂草进化的理解做出重大贡献，这可能有助于管理。最后，这项工作的合作性质将为本科生、研究生和博士后研究人员提供独特的跨学科培训，帮助他们将基因组工具应用于进化遗传学以及作物物种和农业杂草的研究。交付成果：联系PI以获取交付成果

Domestication of wild species is characterized by changes in diverse traits, including plant architecture, fruit and seed morphology, fruit dispersal, and the timing of developmental events. These changes result from human selection to increase yield. Changes in environmental responses are also important in this regard. For instance, higher planting densities could increase yield in many crop species, but densities are limited by developmental responses to crowding, in which time to flowering decreases and relative allocation to structural organs increases at the cost of agronomically desirable traits such as leaf, root, and fruit production. Regardless of the trait selected in a crop species, agricultural weeds exhibit dramatic compensatory evolution that increases weed fitness at the cost of crop productivity. Comparative genetic approaches and genomic tools provide a means to investigate the genetic basis of phenotypic responses to crowding. The research program focuses on crowding responses in Brassica rapa. In addition to domesticated varieties, naturalized populations occur in both agricultural fields and disturbed, weedy sites. Thus, this system is appropriate for investigating both the loci targeted during domestication and those underlying adaptation of weed species to agricultural settings. The research takes advantage of available genomic tools to investigate the genetic basis of competitive responses in agricultural and natural settings. Specific goals include 1) identifying the genetic determinants (known as quantitative trait loci or QTL) for fitness and traits affecting competitive ability in field settings, 2) using controlled light environments to identify QTL important for response to specific environmental cues, 3) quantifying evolutionary responses (measured as allele frequency changes) at QTL determining fitness and phenotypic responses to competition in agricultural and disturbed sites, and 4) cloning QTL for traits important to competitive ability with the aim of determining both genetic targets for crop improvement and loci underlying evolutionary change in agricultural weeds. The experimental research will not only apply current genomic tools to evolutionary studies but also develop and distribute additional genetic resources for dissemination to other researchers. The results will contribute significantly to both crop improvement and an understanding of weed evolution that may aid in management. Finally, the collaborative nature of this work will provide unique, cross-disciplinary training for undergraduates, graduate students, and postdoctoral researchers in the application of genomic tools to evolutionary genetics and the study of both crop species and agricultural weeds. Deliverables: Contact the PI for delivarables