Enhancing diversity in UK wheat through a public sector prebreeding programme

由于人口迅速增长、饮食变化、气候变化和化石燃料库存下降，粮食安全正在成为英国和世界各地的一个关键问题。在未来50年里，我们需要种植的小麦产量将达到大约1万年前农业开始以来的产量。提高英国小麦种植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，这些品种具有更高的产量和更低的营养需求，同时保持谷物的质量。历史上，植物育种研究所（PBI）与野生小麦和相关禾本科植物进行了实验性杂交，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以产生具有优良性能的品种。然而，PBI在1987年被私有化，开发这种新的实验性杂交的研究几乎停止。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增加的新品种。这项建议的目的是重新建立一个小麦育种前计划，在英国开发这种实验性杂交。这样的预育种计划将产生小麦种质，其特征在于下一代的关键性状，如产量，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。我们将使用三种不同但互补的策略开发新的育种前小麦种质，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，我们将从现有的种质资源中开发小麦地方品种或当地适应品种的杂交种质。其次，我们将通过人工杂交四倍体或“面食”小麦与二倍体小麦祖先创造合成六倍体小麦。这捕获了四倍体和二倍体小麦祖细胞中的多样性。CIMMYT育种方案的成功说明了这些合成材料的潜力。第三，我们将使用一种称为外源基因渗入的技术，将含有目的基因的野生近缘种染色体的小片段转移到小麦中。野生和栽培近缘种（外来种）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。这种方法的影响已经通过美国西尔斯的防锈转移来说明，在中间的几年里节省了数十亿美元的经济。在最初的预育种杂交中使用的亲本材料将被表征，以确保最大程度的多样性被利用。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”育种的标记，并为学术研究人员提供关键性状的精细解剖标记。英国育种家和学者感兴趣的与产量有关的关键目标性状已经确定。我们将筛选生物量和增强的N和P利用效率，全蚀和昆虫抗性，包括球茎蝇和蚜虫。该方案将不涉及实际克隆造成这些特定性状的基因，但将提供种质作为这些项目的起点。育种者将利用该项目产生的新种质与其优良品系杂交，开发新品种供农民使用。在该计划中产生的所有信息将存储在一个中央数据库中，种子集中存储，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.