The quikgro potato; an early maturing multiple stress tolerant potato crop for sub-Saharan Africa

马铃薯是一种重要的主食和经济作物，对撒哈拉以南非洲国家（SSA），如肯尼亚和马拉维的粮食安全和当地经济都有贡献。它主要由高原地区（>1500米）的小保持器农民种植，因为块茎发育需要凉爽的温度。对马铃薯的需求正在增长，主要挑战是开发适应低海拔地区农艺和环境条件的当地品种，以扩大生产面积。我们的建议的关键是将联合收割机胁迫耐受性（生物和非生物）与早熟cvs（EMCs）的开发（“Quikgro马铃薯”在60-70天内达到完全成熟，而大多数商业品种超过100天）相结合。我们预计EMC将在温暖的环境中生产快速膨胀的块茎，减轻短雨季和干旱的影响。EMC也不太容易受到疾病的影响（由于一种称为成熟植物抗性的现象; MPR），并且较短的生长周期将使马铃薯能够与其他作物（如水稻和小麦）轮换。育种马铃薯以获得具有改善的胁迫耐受性的种质已被证明是非常困难的，因为马铃薯是四倍体的（它具有4组每条染色体），并且表现出复杂的遗传模式，这使得实现这种遗传复杂性状的改善是一个非常长期的过程。我们的方法是通过开发早熟（70天内）的马铃薯品种来避免压力，因为我们的初步数据表明，这种性状由一些显性基因控制，使其成为更适合的育种目标。在了解马铃薯块茎形成的控制方面的进展已经定义了导致块茎形成的日长信号传导的一些组分，例如发现了与长日照下块茎形成相关的基因（StSP 6A）的另一个版本。此外，在转基因测试系中，编码CEN 1/PENTAL FLOWER 1的基因的沉默显著减少了块茎和花起始的时间。因此，特定等位基因变体的存在影响块茎起始的时间，提供了开发早熟马铃薯的新育种策略。在进一步的工作中（由ERA CAPS Hotsol BB/M004899/1资助），我们已经确定了一个基因（命名为StHot 1），在模型系统中测试时，赋予极端的耐热性。病毒病是肯尼亚和马拉维马铃薯生产系统的主要制约因素。成熟的马铃薯植株随着年龄的增长会产生抗病性（MPR）。我们最近的研究（由BBSRC BB/L011840/1资助）表明，抗性是在开花开始时诱导的，因此，我们假设早熟植物将更具病毒抗性。此外，病毒可以由天然抗性基因控制，并且先前我们已经在马铃薯类型（如上所述）中鉴定了对马铃薯Y病毒的天然抗性，所述马铃薯类型也已经研究了早熟性和块茎化。抗性已经被遗传定位并开发了一个标记。利用我们建立的联系人网络，我们将一种抗病毒的品种玛雅金引入肯尼亚。玛雅黄金通过了肯尼亚国家性能试验，并自发布以来已被证明是非常成功的。我们将研究新发现的基因靶点的功能，以证明EMC将避免非生物和生物胁迫。我们将筛选一系列种质，以测试含有早熟和耐胁迫标记的马铃薯品系是否在非洲环境中表现更好。与SSA科学家的交流将提高现代育种和诊断技术的专业知识。将加强网络，让所有地方利益攸关方参与知识交流和反馈，将调查结果转化为可接受的实际成果。

Potato is a most important staple food and cash crop contributing both to food security and the local economy in countries of sub Saharan Africa (SSA) such as Kenya and Malawi. It is grown mainly by small holder farmers in the highland regions (>1500 m asl) since tuber development requires cool temperatures. Demand for potatoes is growing and the major challenge is to develop local varieties adapted to agronomic and environmental conditions found at lower altitudes to expand the production areas. Key to our proposal is to combine stress tolerance (biotic and abiotic) with the development of early maturing cvs (EMCs) (reaching full maturity in 60-70 days "the Quikgro potato" compared with over 100 days for most commercial varieties). We expect that EMCs will produce tubers that bulk quickly in warmer environments, mitigating the effect of short rainy seasons and droughts. EMCs will also be less susceptible to disease (due to a phenomenon called mature plant resistance; MPR) and the shorter growth cycle would allow potato to fit in rotation with other crops such as rice and wheat. Thus this innovation would have multiple benefits for the people of SSA.Breeding potatoes to obtain germplasm with improved stress tolerances has proved very difficult as potato is tetraploid (it has 4 sets of each chromosome) and exhibits complex inheritance patterns making it a very long term process to achieve improvements in such genetically complex traits. Our approach is to avoid stresses by developing potato varieties that mature early (within 70 days) as our preliminary data indicates that this trait is controlled by a few dominant genes making it a more amenable breeding target. Advances in understanding the control of tuber formation in potato have defined some of the components of day length signalling that lead to tuberisation such as the discovery of an additional version of the gene (StSP6A) that is associated with tuber formation under long days. Additionally, in transgenic tester lines, silencing of a gene encoding CEN1/TERMINAL FLOWER1, significantly decreases the time to both tuber and flower initiation. Thus the presence of a particular allelic variant impacts on the timing of tuber initiation providing a novel breeding strategy to develop early maturing potatoes. In further work (funded by ERA CAPS Hotsol BB/M004899/1) we have identified a gene that (designated StHot1) that confers extreme heat tolerance when tested in model systems.Virus diseases are a major constraint of potato production systems in Kenya and Malawi. Mature potato plants are known to develop resistance to disease as they age (MPR). Our recent investigations (funded by BBSRC BB/L011840/1) have shown that resistance is induced at the onset of flowering, therefore, we hypothesise that early maturing plants will be more virus resistant. In addition, viruses can be controlled by natural resistance genes and previously we have identified natural resistance to potyviruses in the potato types (described above) that have also been studied for earliness and tuberisation. The resistance, has been genetically mapped and a marker developed. Using our network of established contacts, we introduced a virus resistant cultivar Mayan Gold containing this resistance to Kenya. Mayan Gold passed Kenyan National Performance Trials and since release has proved highly successful. We will investigate the function of the newly identified gene targets to achieve proof of principle that EMC's will avoid both abiotic and biotic stresses. We shall screen a range of germplasm to test whether potato lines containing markers for earliness and stress tolerance will perform better in the African environment. Exchange with SSA scientists will enhance expertise in modern breeding and diagnostic technologies. Networks will be strengthened to engage all local stakeholders for knowledge exchange and feedback to translate findings into acceptable and practical outcomes.