Using wild ancestor plants to make rice more resilient to increasingly unpredictable water availability

在全球气候变化的情况下，使粮食生产跟上人口增长的步伐是一项重大挑战。极端降雨量的高和低都日益限制粮食生产，特别是对最贫穷的农民。此外，预计在气候变化的影响下，干旱和洪水将更频繁地发生，而农业用水的可用性将下降。“绿色革命”导致亚洲大部分地区的水稻产量翻了一番，但现在对水稻的需求超过了产量，联合国粮农组织预测，到2050年，水稻产量需要增加50%才能满足人口增长。全球水稻产量的四分之一（在印度上升到45%）是在雨养环境中生产的，因此面临气候变化的严重风险。现代植物育种的新发展使科学家们能够解决这个问题。利用基于DNA的分子标记来预测成年植物在干旱等具有挑战性的环境下的表现，可以加快育种速度，并将不同的表型或性状组合在一起，从一个品种转移到另一个品种。这些分子工具使选择过程更加有效，因此以前需要六代才能完成的事情现在可以在两代内完成。然而，在水稻等作物数百年的驯化过程中，遗传多样性的丧失意味着与现代品种相关的种质资源为应对21世纪的挑战提供了有限的改进空间。这个项目令人兴奋的地方在于，我们将利用我们在美国康奈尔大学的一个实验室开发的新技术平台，从祖先的野生水稻物种中获取有价值的遗传变异，将其引入在印度广泛种植的现代精英品种，并识别出在干旱条件下由于野生物种DNA片段的存在而提高产量的新品种。印度的中央水稻研究所（Central Rice Research Institute）将对携带野生品种不同DNA片段的数百种不同品种进行田间试验，同时，约克大学（university of York）和康奈尔大学（Cornell）的研究人员将进行一系列不同的实验，以了解是什么原因导致特定品种的抗旱性增强。有了这一新的认识，将有可能开发出新的基于DNA的分子标记，使野生物种的遗传变异能够有效地转移到广泛的商业水稻品种上。因此，在为期四年的项目中，产出的不仅是改良的水稻品种，而且是快速部署干旱的新育种工具，赋予多种水稻品种遗传变异。然而，除了产量表现外，当地社区对水稻新品种的采用还取决于多种因素，其中最重要的是粮食品质。文化和社会问题，如性别的作用，在决定新品种的成功方面也起着重要作用，为了解决这个问题，我们将进行一项社会经济研究，以评估任何新品种的可能吸收模式及其对农民收入的影响。将评价新的水稻品种对产量、每单位生产成本和每一特定投入（土地、劳动力、肥料、种子）的总产量的影响，并将在农场进行试验和参与性评价，作为品种田间试验的一个组成部分。该项目还将模拟新品种的影响，以量化当前和未来随着气候变化在干旱易发地区如何提高产量。这些信息以及我们的社会经济研究成果将使发展中国家的决策者了解新品种的社会经济效益，从而改进采用最有效的战略来解决粮食不安全和贫困问题。

Enabling food production to keep pace with population growth in the face of global climate change is a significant challenge. Both high and low extremes in rainfall increasingly limit food production, particularly for the poorest farmers. Furthermore, droughts and floods are predicted to occur more frequently under climate change, whilst the availability of water for agriculture will decline. The "green revolution" resulted in a doubling of rice yields across much of Asia, but demand for rice now exceeds production and UN FAO predictions suggest rice yields will need to increase by 50% by 2050 to meet population growth. A quarter of global rice production, rising to 45% in India, is in rain-fed environments thus at serious risk from climate change. New developments in modern plant breeding are allowing scientists to address this problem. The use of DNA based molecular markers that predict how adult plants perform under challenging environments such as drought allow breeding to be speeded up and different phenotypes or traits to be combined and transferred from one variety to another. These molecular tools make the selection process much more efficient so that what previously would have taken six generations can now be done in two. However, the loss of genetic diversity during the hundreds of years of domestication of crops such as rice means that the germplasm associated with modern cultivars offers limited scope for the improvements that are needed to meet the challenges of the 21st Century. The exciting thing about this project is that we will use new technology platforms developed in one of our laboratories at Cornell University, USA, to access valuable genetic variation from ancestral wild species of rice, introduce this to modern day elite cultivars that are widely grown in India and identify new varieties that have increased yields under drought conditions due to the presence of small segments of DNA from the wild species. Field trialling of hundreds of different lines carrying different segments of DNA from the wild species will be conducted by the Central Rice Research Institute in India and in parallel researchers at the Universities of York and Cornell will carry out a range of different experiments to understand what causes increased drought resistance in specific lines. With this new understanding it will be possible to develop new DNA based molecular markers that allow the genetic variation from the wild species to be efficiently transferred to a wide range of commercial rice cultivars. So the outputs during the four year project will not only be improved rice varieties but also new breeding tools for rapid deployment of drought conferring genetic variation to multiple rice cultivars. However, the adoption of new rice varieties by local communities is dependent on multiple factors in addition to yield performance with grain quality being one of the most important. Cultural and sociological issues such as the role of gender also play a significant part in determining the success of a new cultivar and in order to address this we will perform a socioeconomic study to assess the likely uptake patterns of any new varieties and their impact on farmers' incomes. The impact of new rice cultivars on yield, per unit cost of production, and total production per specific input (land, labour, fertilizers, seeds) will be evaluated and on-farm testing and participatory evaluation will be an integral component of cultivar field trials. This project will also model the impact of new varieties to quantify how yields are enhanced in drought-prone landscapes currently and in the future as climate changes. This information along with the outputs from our socio-economic studies will inform policy makers in developing countries about the socio-economic benefits of new varieties and thus improve adoption of the most effective strategies to address food insecurity and poverty.