Developing a natural variation platform for pest-resistant cassava breeding

木薯（Manihot esculenta）是热带地区第三重要的热量来源，也是非洲、亚洲和拉丁美洲数百万人的主食。与气候变化有关的气温上升的预测有利于木薯的生产力，这种作物在与干旱和高温有关的紧张生长条件下表现良好。然而，木薯易受多种病虫害的影响，对木薯病虫害与气候变化有关的迁移的预测预测，产量将遭受重大损失。因此，木薯育种者在其育种规划中优先考虑与病虫害抗性相关的性状。在拉丁美洲，对木薯生产的最大病虫害威胁是粉虱、木薯蛙皮病和细菌性枯萎病。细菌性枯萎病在非洲和亚洲的木薯种植区也很普遍。这些会导致76-92%的产量损失。我们可以通过常规或分子育种技术探索木薯的野生近缘种，引入新的抗病性状。作物野生近缘种已被应用于小麦、水稻、番茄、马铃薯、向日葵等作物中，提供了新的抗病虫害来源。哥伦比亚国际热带农业中心（CIAT）的遗传资源计划（GRP，基因库）目前拥有约4900种木薯及其野生亲缘种。基因库的使命包括保存材料，但也旨在使材料可供使用。然而，由于对绝大多数品种的信息有限，用户甚至基因库管理人员很难选择可能包含有用育种特性的材料。通过对木薯野生近缘种的基因组测序，揭示其抗性基因的遗传多样性。此外，我们将检查这些品种对白蝇、木薯蛙皮病和细菌性枯萎病的防治效果。我们还将开发新的工具来探索这些数据集，使育种者更容易选择哪些野生材料包括在他们的计划中。通过该项目产生的所有信息都将通过GRP门户网站公开提供给育种者和研究人员。育种者往往对将野生材料纳入其育种计划持谨慎态度，因为野生物种给后代带来了理想和不理想特征的混合。育种是一个缓慢的过程，去除不良性状可能需要许多代。因此，掌握更多关于这些野生物种的物理和遗传特征的信息将有助于育种者做出最适当的植物选择，并鼓励将野生近缘种纳入木薯中，为木薯提供新的病虫害抗性来源。CIAT在哥伦比亚和越南设有中心，研究人员在全球53个国家工作。拥有新的抗虫害来源将使许多国家的木薯育种者和种植者受益，但我们将以哥伦比亚、巴西、越南、柬埔寨和老挝人民民主共和国的育种者为目标。通过减少病虫害造成的损失，该项目将促进可持续农业，提高粮食系统对气候变化的抵御能力。

Cassava (Manihot esculenta) is the third most important source of calories in the tropics and a key staple for millions in Africa, Asia and Latin America. Predictions of rising temperatures linked to climate change favour the productivity of cassava, a crop that performs well under stressful growing conditions linked to drought and high temperatures. However, cassava is susceptible to a number of pests and diseases, and projections of movement of cassava pests linked to climate change predict substantial yield losses. As such, cassava breeders are prioritising traits linked to pest and disease resistance within their breeding programmes. Within Latin America, the largest pest and disease threats to cassava production are whitefly, cassava frogskin disease and bacterial blight. Bacterial blight is also prevalent throughout cassava growing regions in Africa and Asia. These can cause yield losses of 76-92%. We can explore cassava's wild relatives to introduce novel disease resistance traits through conventional or molecular breeding techniques. Crop wild relatives have been used in wheat, rice, tomato, potato, sunflower and other crops to provide sources of novel resistance to pests and diseases. The Genetic Resources Program (GRP, genebank) at the International Center for Tropical Agriculture (CIAT) in Colombia currently houses ~4,900 accessions of cassava and its wild relatives. The mission of genebanks includes the conservation of materials, but also aims to make the material available for use. However having limited information for the vast majority of accessions makes it difficult for users, or even genebank managers, to select materials that may contain useful properties for breeding. Through sequencing the genomes of cassava wild relatives we will reveal the genetic diversity of their resistance genes. In addition we will check the performance of these species against whitefly, cassava frogskin disease and bacterial blight. We will also develop novel tools to explore these datasets, making it easier for breeders to choose which wild materials to include in their programs. All the information generated through this project will be made publicly available for breeders and researchers to access via the GRP portal.Breeders tend to be cautious about including wild materials into their breeding programs as wild species bring a mixture of desirable and undesirable characteristics into the offspring. Breeding is a slow process, and removing the undesirable traits can take many generations. Therefore, having more information about the physical and genetic characteristics of these wild species will help breeders to make the most appropriate choices of plants to use and encourage the inclusion of wild relatives to provide novel sources of pest and disease resistance into cassava.CIAT has centres in Colombia and Vietnam, with researchers working in 53 countries worldwide. Having novel sources of pest resistance will benefit cassava breeders and growers in many countries, however we will target breeders in Colombia, Brazil, Vietnam, Cambodia and Lao People's Democratic Republic. Through the reduction of losses due to pests and diseases, this project will contribute to sustainable agriculture and increasing the resilience of food systems to climatic variability.