Characterizing phenotypic variation, physiological costs, and global gene expression associated with shade avoidance in selected crop species

植物的避荫反应被认为是一种适应性的、可塑的反应，它增加了在自然环境中成功繁殖的可能性。在农业环境中，这种避荫反应也应该使作物物种与杂草更具竞争力。然而，避荫可能以牺牲生殖健康为代价。以前没有研究将避荫作为解释作物和杂草竞争结果的机制。因此，为了探讨遮荫回避在作物-杂草相互作用中的作用，我们提出了以下三个目标：(1)用数学方法定义选定作物种质内表型变异对光质量变化的响应的可塑性指数；该目标的目的是预测杂草条件下作物的田间表现，(2)确定避荫的成本，通过作物产量或随后非生物胁迫的表型可塑性损失来衡量，以及(3)发现与杂草诱导的玉米避荫相关的关键代谢和信号通路。这些目标将在现场和实验室条件下进行。该项目将产生新的知识，有关选定作物物种对早期杂草竞争引起的胁迫的生理和分子反应。这一新知识将直接用于加拿大和北美的公共和私人作物育种项目。我们期望从这些研究中获得的知识将用于开发新的、更耐杂草的作物杂交品种。这项技术的商业化将提高农场净收入，减少环境中的农药负荷，从而对加拿大的农村经济有直接的好处。

The shade avoidance response of plants is considered to be an adaptive, plastic response that increases the probability of successful reproduction in natural environments. Within an agricultural environment, this shade avoidance response should also enable crop species to be more competitive with weeds. However, shade avoidance may be expressed at a cost to reproductive fitness. No study has been conducted previously to associate shade avoidance as a mechanism to explain the outcome of crop and weed competition. Therefore, to explore the role of shade avoidance in crop-weed interactions, we propose the following three objectives: (1) to mathematically define a plasticity index of phenotypic variation within selected crop germplasm in response to changes in light quality; the intent of this objective is to predict crop field performance under weedy conditions, (2) to determine the cost of shade avoidance, as measured by crop yield or as a loss of phenotypic plasticity to subsequent abiotic stresses, and (3) to discover key metabolic and signaling pathways associated with weed-induced shade avoidance in corn. These objectives will be addressed under field and laboratory conditions. This project will generate new knowledge pertaining to the physiological and molecular response of selected crop species to stress caused by early weed competition. This new knowledge will be of direct use to public and private crop breeding programs throughout Canada and North America. We anticipate that knowledge generated from these studies will be used to develop new, more weed tolerant crop hybrids and varieties. The commercialization of this technology will improve net on-farm income, reduce pesticide loading into the environment, and thereby be of direct benefit to the rural economy of Canada.