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储量下降，食品安全正在成为英国乃至全世界的一个关键问题。在接下来的50年里，我们需要种植的小麦与大约1万年前农业开始以来生产的小麦一样多。提高英国小麦产量的要求给研究带来了重大挑战。我们需要开发新的小麦品种，使其产量更高，营养需求更低，同时保持谷物的质量。从历史上看，植物育种研究所（PBI）用野生小麦和相关牧草进行了实验杂交，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选择来产生具有优良性能的品种。然而，PBI在1987年被私有化，开发新的实验性杂交品种的研究几乎停止了。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的实验品系来开发产量更高的新品种。这一提议的目的是在英国重新建立小麦的预育种计划，开发这样的实验性杂交品种。这样的预育种计划将产生具有下一代关键性状（如产量）特征的小麦种质，并将在育种计划和学术界中确定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种小麦种质，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，我们将从现有种质资源中提取的小麦地方品种或地方适应品种的杂交中开发种质资源。其次，我们将通过将四倍体或“面食”小麦与二倍体小麦祖体细胞人工杂交来创造合成六倍体小麦。这捕获了四倍体和二倍体小麦祖先的多样性。这些合成材料的潜力在CIMMYT育种计划中的成功证明了它们的潜力。第三，我们将使用一种称为外来基因渗入的技术，将含有目标基因的野生近缘种的一小段染色体转移到小麦中。野生和栽培亲缘种（外来种）为产量、气候变化和环境相关的所有重要性状提供了丰富的遗传变异。这种方法的影响已经通过西尔斯在美国的防锈能力转移来说明，在这期间的几年里，西尔斯为其经济节省了数十亿美元。在最初的预育种杂交中使用的亲本材料将被鉴定，以确保最大程度的多样性得到利用。新的测序技术将用于生成非常高密度的图谱，为育种公司提供“精确”育种标记，为学术研究人员提供精细解剖关键性状的标记。英国育种家和学术界都感兴趣的与产量相关的关键目标性状已经确定。我们将筛选生物量和提高氮磷利用效率，全蚀性和抗虫性，包括球蝇和蚜虫。该计划将不涉及对这些特殊性状负责的基因的实际克隆，但将提供种质作为此类项目的起点。本项目产生的新种质资源将由育种家利用，与其优良系杂交，培育新品种供农民使用。该项目产生的所有信息都将存储在一个中央数据库中，种子也将集中存储，这两者都可以在英国免费提供给学者和育种者。

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.