Enhancing diversity in UK wheat through a public sector prebreeding programme

由于人口快速增长、饮食变化、气候变化和化石燃料库存下降，粮食安全正成为英国和世界范围内的一个关键问题。在接下来的50年里，我们将需要种植大约10000年前开始农业以来所生产的小麦谷物。增加英国小麦种植数量的要求给研究带来了重大挑战。我们需要开发出产量更高、营养需求更低、同时保持粮食品质的小麦新品种。在历史上，植物育种研究所(PBI)与野生小麦和相关牧草进行实验杂交，能够将高农艺潜力的性状转移到小麦中，但仍需要进一步的育种者选择才能产生表现优异的品种。然而，PBI在1987年被私有化，开发这种新的试验性杂交的研究几乎停止了。这给小麦育种者造成了一个主要的瓶颈，因为他们没有必要的新实验品系来开发产量更高的新品种。这项提议的目标是在英国重新建立小麦的预育种计划，开发这样的试验性杂交。这种前期育种计划将产生小麦种质，以产量等下一代关键性状为特征，并将在育种计划和学术界确定用于选择这些性状的遗传标记。我们将利用三种不同但互补的策略，开发新的预育小麦种质，以最大限度地将多样性和有益性状引入一系列小麦品系。首先，我们将从小麦地方品种或地方适应品种的杂交中开发种质，这些品种来自现有的种质资源。其次，我们将通过人工将四倍体小麦或‘意大利面’小麦与二倍体小麦祖先杂交来创造合成六倍体小麦。这捕捉到了四倍体和二倍体小麦祖先的多样性。这些合成材料在CIMMYT育种计划中的成功证明了它们的潜力。第三，我们将使用一种名为异源导入的技术，将含有目标基因的野生近亲的小段染色体转移到小麦中。野生和栽培近亲(外来物种)为所有与产量、气候变化和环境相关的重要性状提供了丰富的遗传变异。这种方法的影响从西尔斯在美国转移防锈技术的例子中得到了证明，在这几年里，西尔斯为美国经济节省了数十亿美元。在最初的预繁育杂交中使用的亲本材料将被特化，以确保最大程度地利用多样性。新的测序技术将被用来生成非常高密度的图谱，为育种公司提供‘精确’育种的标记，为学术研究人员提供精细剖析关键性状的标记。与产量相关的关键目标性状已经确定，这是英国育种者和学者都感兴趣的。我们将筛选生物量和提高N和P的利用效率、全食和抗虫性，包括鳞翅目苍蝇和蚜虫。该计划将不涉及实际克隆负责这些特定特征的基因，但将提供种质作为此类项目的起点。该项目产生的新种质将被育种者利用，与他们的优良品系杂交，开发供农民使用的新品种。该计划中产生的所有信息都将存储在一个中央数据库中，种子将集中存储，两者都可以在英国境内免费提供给学者和饲养者。

Food security is becoming a critical issue both in the UK and worldwide due to rapid population expansion, dietary changes, climate change and declining fossil fuel stocks. In the next 50 years, we will need to grow as much wheat grain as has been produced since the beginning of agriculture, some 10,000 years ago. The requirement to enhance the amount of wheat grown in the UK creates a major challenge for research. We need to develop new wheat varieties which have higher yields with lower nutrient requirements, whilst retaining the quality of the grain. Historically the Plant Breeding Institute (PBI) made experimental crosses with wild wheats and related grasses, capable of transferring traits of high agronomic potential into wheat, but still requiring further breeder selection to generate varieties with elite performance. However, the PBI was privatised in 1987 and research developing new experimental crosses of this kind almost stopped. This has created a major bottleneck for wheat breeders, because they do not have the necessary new experimental lines from which to develop new varieties with increased yield. The objective of this proposal is to re-establish a pre-breeding programme in wheat developing such experimental crosses in the UK. Such a pre-breeding programme will produce wheat germplasm, characterised for the next generation of key traits, such as yield, and will identify genetic markers for selecting these traits, in breeding programmes and for the academic community. We will develop novel pre-breeding wheat germplasm, using three different but complementary strategies, to maximise the introduction of diversity and beneficial traits into a range of wheat lines. First we will develop germplasm from crosses involving wheat landraces or locally adapted varieties, derived from exiting germplasm collections. Secondly we will create synthetic hexaploid wheats by artificially crossing tetraploid or 'pasta' wheats with diploid wheat progenitors. This captures diversity in both the tetraploid and diploid wheat progenitors. The potential of these synthetics is illustrated by their success in the CIMMYT breeding programme. Thirdly we will use a technique called alien introgression, to transfer small segments of chromosomes of wild relatives containing the target genes, into wheat. Wild and cultivated relatives (alien species) provide a wealth of genetic variation for all characters of importance relative to yield, climate change and the environment. The impact of this approach has been illustrated by the transfer of rust resistance by Sears in the US saving its economy several billion dollars in the intervening years. The parental material used in the initial prebreeding crosses will be characterised to ensure the maximal levels of diversity are being exploited. New sequencing technologies will be used to generate very high density maps, providing the breeding companies with markers for 'precision' breeding, and the academic researchers with markers for fine dissection of key traits. Key target traits relating to yield, of interest to both UK breeders and academics, have been identified. We will screen for, biomass and enhanced N and P use efficiency, Take-All and insect resistance including Bulb fly and Aphids. The programme will not involve the actual cloning of the genes responsible for these particular traits, but will provide the germplasm as the starting point for such projects. The new germplasm generated in this project will be exploited by breeders for crossing with their elite lines to develop new varieties for use by farmers. All the information generated in the programme will be stored in a central database, and seed stored centrally, both being freely available within the UK to both academics and breeders alike.