15-IWYP -Wider and faster: high-throughout phenotypic exploration of novel genetic variation for breeding high biomass and yield in wheat

到2050年，全球人口将达到90亿，迫切需要将粮食产量提高至少60%。小麦产量在世界上许多地区已经趋于稳定，原因是缺乏农学上重要性状的新遗传变异，加上气候变化的影响。现代小麦缺乏遗传变异是其进化过程中重大遗传瓶颈的直接后果。因此，小麦野生祖先和地方品种中农艺学上重要性状的遗传变异量明显大于当今的优良品种。与现代小麦相反，其远亲为潜在的所有重要农艺性状（包括光合作用）提供了巨大的遗传变异资源。然而，只有一小部分现有的遗传变异已被利用在育种方案中，现在人们认识到，提高主要作物的谷物产量需要提高总干重产量，而这必须主要通过提高辐射利用效率来实现。提高芸香需要更高的叶片和冠层光合速率，这仍然是支撑未来产量进步的重要目标。有充分的证据表明，C3光合作用并不适合高生物量，而且存在未实现的遗传潜力，通过遗传改良提高小麦光合作用的最快途径是寻找可用于育种和预育种的相关性状的现有变异。这可能代表了光合作用的新变异，这些变异要么在育种过程中从小麦基因组中丢失，要么从未出现过。特征包括（1）Rubisco的性质（2）Rubisco活性的调节（3）光保护过程（4）电子传递/ RuBP再生（5）光呼吸（6）冠层结构和光合作用和色素的分布（7）内部叶片和叶绿体形态（8）气孔响应（对土壤和大气水）和叶片水分利用效率。诺丁汉的项目目标是将携带靶基因但不含任何有害基因的相关物种的小染色体片段转移到小麦中。在这个项目中，我们将产生，使用广泛的杂交，地方品种和现有的品种，线与其光合特性的实质性变化，并使用高通量筛选技术，以确定后代增强光合能力和效率。我们将研究光合作用变化的遗传基础，并与IWYP HUB将这些发现整合到育种前和育种策略中。该计划将汇集一个多学科研究团队：UoN（广泛杂交，小麦生理学，光合作用表型），（UoB：遗传标记分析），埃塞克斯大学（UoE：新的光合作用表型，卡尔文循环工程），兰开斯特大学环境中心（LEC：全植物碳增益和水利用，Rubisco工程），CIMMYT（田间表型和基因型）。

With the global population set to reach nine billion by 2050, there is an urgent need to increase food production by at least 60%. Wheat production has plateaued in many areas of the world due to a lack of novel genetic variation for agronomically important traits compounded by the effects of climate change. The lack of genetic variation in modern wheat is a direct consequence of significant genetic bottlenecks during its evolution. As a result, the amount of genetic variation for agronomically important traits available in wild ancestors and landraces of wheat is significantly greater than in present day elite varieties. In contrast to modern wheat, its distant relatives provide a vast resource of genetic variation for potentially all agronomically important traits, including photosynthesis. However, only a fraction of the genetic variation available has been exploited in breeding programmes.There is now recognition that improved grain yields of major crops require enhanced total dry weight production which must arise mostly from an improvement of radiation-use efficiency (RUE). Raising RUE requires a higher leaf and canopy photosynthesis rate and this remains an important target to underpin future yield progress. There is compelling evidence that C3 photosynthesis is not optimized for high biomass and moreover there is unrealized genetic potential.The fastest way to raise photosynthesis by genetic improvement in wheat is to seek existing variation in relevant traits that can be used for breeding and pre-breeding. This may represent new variation in photosynthesis that was either lost from the wheat genome during breeding or never present. Traits include (1) properties of Rubisco (2) regulation of Rubisco activity, (3) photoprotective processes (4) electron transport/ RuBP regeneration (5) photorespiration (6) canopy structure and distribution of photosynthesis and pigments (7) internal leaf and chloroplast morphology (8) stomatal responses (to soil and atmospheric water) and leaf water use efficiency. objective of the programme at Nottingham is to transfer small chromosome segments from related species which carry a target gene but lack any deleterious genes, into wheat. In this project we will generate, using wide crosses, landraces and existing cultivars, lines with substantial variation in their photosynthetic properties and use high throughput screening techniques to identify progeny with enhanced photosynthetic capacity and efficiency. We will investigate the genetic basis of the photosynthetic variation and with the IWYP HUB integrate these discoveries into a pre-breeding and breeding strategy. The programme will bring together a multi-disciplinary research team: UoN (wide crossing, wheat physiology, photosynthesis phenotyping), (UoB: Genetic marker analysis), University of Essex (UoE: novel photosynthesis phenotyping, Calvin cycle engineering), Lancaster University Environment Centre (LEC: whole plant carbon gain and water use, Rubisco engineering), CIMMYT (field phenotyping and genotyping).