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

植物的遮荫回避反应被认为是一种适应性的可塑性反应，它增加了在自然环境中成功繁殖的可能性。在农业环境中，这种遮荫反应也应该使作物物种能够更好地与杂草竞争。然而，遮荫回避可能是以生殖适合性为代价的。以前还没有研究将遮荫回避作为一种机制来解释作物和杂草竞争的结果。因此，为了探索遮荫在作物-杂草互作中的作用，我们提出了以下三个目标：(1)从数学上定义作物种质内表型变异的可塑性指数，以响应光质的变化；这个目标的目的是预测杂草条件下的作物田间表现；(2)确定遮荫的代价，以作物产量或随后的非生物胁迫下表型可塑性的损失来衡量；(3)发现与杂草诱导的玉米遮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实现。该项目将产生有关选定作物物种对早期杂草竞争造成的胁迫的生理和分子反应的新知识。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计划。我们预计，这些研究产生的知识将用于开发新的、更耐杂草的作物杂交种和品种。这项技术的商业化将提高农场的净收入，减少环境中的农药负荷，从而对加拿大农村经济产生直接好处。

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.