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

面对全球气候变化，使粮食生产与人口增长保持同步是一项重大挑战。极端降雨量的高低都日益限制了粮食生产，特别是对最贫穷的农民来说。此外，预计在气候变化下，干旱和洪水将更频繁地发生，而农业用水的可获得性将下降。“绿色革命”导致亚洲大部分地区的大米产量翻了一番，但大米现在供不应求，联合国粮农组织的预测显示，到2050年，大米产量需要增加50%才能满足人口增长的需求。全球大米产量的四分之一在印度上升到45%，处于雨水滋养的环境中，因此面临着气候变化的严重风险。现代植物育种的新发展使科学家能够解决这个问题。使用基于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中的表现，可以加快育种速度，将不同的表型或性状结合起来，并从一个品种转移到另一个品种。这些分子工具使选择过程变得更加高效，因此以前需要六代的工作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世纪的挑战所需的改良提供了有限的空间。这个项目令人兴奋的是，我们将使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，获取原始野生水稻物种的宝贵遗传变异，将其引入在印度广泛种植的现代精英品种，并识别由于存在野生物种的小片段DNA而在干旱条件下提高产量的新品种。印度中央水稻研究所将对数百个携带野生物种不同DNA片段的不同品系进行田间试验，同时约克大学和康奈尔大学的研究人员将进行一系列不同的实验，以了解是什么导致特定品系的抗旱性增强。有了这一新的认识，就有可能开发新的基于DNA的分子标记，使野生物种的遗传变异有效地转移到广泛的商业水稻品种上。因此，在四年计划期间的产出将不仅是改良的水稻品种，而且还将是快速部署干旱的新的育种工具，使遗传变异被赋予多个水稻品种。然而，当地社区对新水稻品种的采用除了取决于产量表现外，还取决于多种因素，其中最重要的因素之一是稻米质量。文化和社会学问题，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学研究，以评估任何新品种可能的吸收模式及其对农民收入的影响。将评估新水稻品种对产量、单位生产成本和每特定投入(土地、劳动力、化肥、种子)的总产量的影响，田间试验和参与性评价将是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多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政策制定者了解新品种的社会经济效益，从而促进采取最有效的战略来解决粮食不安全和贫穷问题。

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.