A genomics-assisted synthetic hexaploid wheat gene isolation and pre-breeding platform for improved heat tolerance and sustainable production

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Background: Wheat is the most important cereal for direct human consumption, and is crucial to populations most exposed to current and anticipated future failures in global food security. India is the world's second largest producer of wheat, while the UK is currently one of the world's highest yielding environments. However, a relatively narrow genetic base currently hampers wheat improvement by reducing our ability to breed new varieties adapted to changing environmental and disease pressures. In India, heat stress is having an increasingly negative impact on wheat yields, while in the UK losses due to drought loss cost >£60 million per year. The detrimental of heat stress in both countries is set to worsen, given current climate change scenarios for India and NW Europe. This will have serious impacts on India's wheat farming community (the majority of which grow wheat for their own consumption), as well as on UK production and global food security. Increasing global demand for wheat, coupled with factors such as the effects of climate change and the necessity for sustainable wheat production, means that investment in breeding approaches that incorporate information on wheat genetic variation ('genome-assisted' approaches) are now widely accepted as critical. However, to fully exploit such approaches, novel wheat lines which possess desirable traits not normally found in currently used varieties must first be identified and utilised. The wild relatives of wheat possess immense genetic diversity, but most of this is underutilized. Useful genetic variation can be transferred into elite wheat backgrounds from progenitor species by recreating the original natural hybridisation process that occurred 10,000 years between two wheat progenitors to create modern bread wheat. These novel wheats (called 'synthetic hexaploid wheat', SHW) inject novel genetic variation into breeding programmes aimed at developing new varieties with increased tolerance to environmental stress and other sub-optimal environmental conditions. Project aims and outcomes: This project aims to create novel SHW lines (using progenitor lines specifically selected to harbour heat stress tolerance), and use these to cross into modern Indian and UK varieties to create a large population of 1,500 progeny. This population will form the basis of a unique wheat biological resource upon which genomic-assisted approaches can be applied to investigate the novel genetic determinants of heat tolerance introduced via SHW. This will be achieved by:(1) Identifying and typing the genetic variants present in the population.(2) Using novel approaches to undertake detailed assessment of how each of the 1,500 progeny lines performs under heat stress. (3) Assessing how different genes and gene variants are expressed when exposed to heat stress. These datasets will be analysed to identify the genetic regions originating from the SHW parental lines that confer tolerance to heat stress. In this way, the project will simultaneously identify genetic markers that tag increased heat tolerance, as well as provide Indian- and UK-adapted wheat lines that express the beneficial traits. The unique position of the project partners at the interface between wheat research and breeding will be leveraged to promote rapid translation of project outcomes into national wheat breeding programmes. This project provides biological and genetic resources/tools alongside a programme of knowledge exchange and capacity building, which will aid the progress of wheat R&D and breeding in India and the UK.