Yellow Wheat Blossom Midge (YWBM) is a poorly understood and often under-reported insect pest of wheat, the UK's most widely grown crop. Midge larvae feed on the wheat flower, preventing grain formation and leading to significant yield losses. All wheat varieties are reported to be susceptible to this pest. In some years, the ideal conditions required for adult midges to emerge from dormancy in the soil, mate and lay eggs occur just as the wheat is at its most vulnerable to attack. However, YWBM damage varies from year-to-year and is currently difficult to predict. This project aims to further our knowledge of this pest and its impact on the wheat crop. In related pest midges, adult females produce a volatile sex pheromone which allows adult males to locate females prior to mating. Synthetic versions of these pheromones released from simple traps are widely used in many crops to monitor midge pests and identify when and where control strategies must be applied. By identifying the sex pheromone of YWBM in this project, we will have completed the necessary first step in developing an appropriate monitoring tool for use in UK wheat crops. We have previously identified experimental NIAB wheat lines that showed no YWBM damage in seasons when midge levels were high in adjacent varieties. With help from plant breeding companies, we will test these promising lines more thoroughly. We will grow them in small field plots at several locations across the UK, and measure YWBM levels in resistant NIAB lines and in susceptible commercial varieties. We will collect unripe wheat ears containing live YWBM larvae, and soil samples containing dormant pupae, from these and other sites to provide a source of midges. Young midges will be reared individually at NIAB East Malling until they emerge as adults. NIAB and NRI specialists will collect the volatile chemicals produced by groups of adult males and females. Through electrophysiological experiments at NRI, we will identify which chemicals produced by female midges can be detected by the males as likely components of the sex pheromone. Using chemical analysis and our experience in identifying other midge pheromones, we will begin identification of the YWBM sex pheromone components. If supply of midges and time allows, we will synthesize these likely components for further testing. NIAB will also explore the feasibility of maintaining a laboratory colony of YWBM for future work into the life cycle of this important pest.

Control of fertility and successful reproduction is key to grain set and thus crop yield in cereals. Self-pollinating crops tend to have lower yield capability than hybrids generated by intercrossing between elite lines. This "Hybrid Vigour" has been shown to increase yield, but also abiotic and biotic stress resistance. Hybrid crops thus provide opportunities to increase yield and productivity in a sustainable manner. However, the challenge for hybrid production is the need to avoid the natural tendency for many crops to self-fertilise prior to outcrossing, whilst ensuring effective cross-pollination for hybrid seed production. Mechanisms that control fertility in a reversible manner are critical to deliver such systems and this is a key goal for wheat breeding, since major yield enhancements are possible from hybrid wheat. Hybrid seed production also relies upon effective males to pollinate the female lines, therefore traits for optimal pollen production, viability and release are also of major importance. Wheat pollen development is particularly sensitive to environmental damage, with rapid reductions in viability post anthesis, combined with general sensitivity to abiotic stress (e.g. high and low temperature) during development. Reductions in fertility due to environmental stress are often seen in wheat crops and these can have major impacts on yield. Reproductive resilience to variable environmental conditions and abiotic stress is therefore critical to sustainable yields. This can only be delivered by detailed knowledge of pollen development and systems to regulate fertility. Deep understanding of cereal reproduction is therefore key to the development of wheat hybrid breeding systems. This proposal will address these issues by providing greater understanding of pollen development in cereals towards developing switchable systems for the control of wheat fertility, but also by identifying traits for enhanced pollen production and viability, particularly under environmental stress, which are critical for ensuring successful pollination in breeding programmes. By investigating the mechanisms behind these traits and by generating tools for breeding and selection, effective breeding to increase crop productivity and resilience will be realised. The project will use our progress in understanding cereal pollen development to develop systems for controlling cereal fertility, focussing on wheat. In addition introgression lines and breeding populations will be screened to identify traits for optimal fertilisation, including high pollen production, release and durability. These will be focused around the impact of environment, particularly temperature and day length, on pollen fertility. We will determine the benefit and stability of these traits in elite commercial germplasm, enabling their potential to be determined. We will also assess natural variation at these fertility loci and develop markers to enable these traits, which could potentially impact on fertility particularly under different environmental conditions, to be followed in breeding populations.

Wheat yellow rust caused by the fungus Puccinia striiformis f. sp tritici is a substantial threat to wheat production worldwide and recently re-emerged as a major constraint on UK agriculture. Its importance to global food security is reflected by the significant contribution of wheat to the calorific and protein intake of human kind (approximately 20%). The devastating impact of this disease gives a deep sense of urgency to breeders, farmers and end users to improve surveillance. To address this, we recently developed a novel approach called "field pathogenomics" for pathogen population surveillance. This method, based on new gene sequencing technology, allows us to acquire data directly from field samples of rust-infected wheat. By implementing this approach we found that the yellow rust population across the UK underwent a major shift in recent years. Genetic analyses revealed four distinct lineages that correlated to the phenotypic groups determined through traditional pathology-based virulence assays. The overall aim of this project is to apply gene-sequencing technology to the surveillance of yellow rust and undertake comprehensive global population genetic analyses of this important plant pathogen. Currently, the assessment of genotypic diversity is not included within UK national surveillance activities for wheat rust. Our new approach enables the integration of high-resolution genotypic data into pathogen surveillance activities that is vital to improve our understanding of the genetic sub-structure within a population. The proposed research aims to: (1) Analyze the threat of potential exotic incursions of wheat yellow rust to the UK by mapping the global population structure, (2) exploit the rust genotype data (Obj. 1) to confirm outbreaks on particular wheat varieties and look for associations between pathogen genotypes and host pedigrees, (3) generate information on whether genotypic diversity shifts over time at a locality and whether early appearing rust genotypes are predictive of late season genotypes and (4) develop appropriate open-source tools to ensure all data generated herein is released into the public domain as soon as possible and in a format that is suitable for breeders, pathologists and the wider demographic. This project aims to equip the UK with the latest genomic tools, facilitate more efficient varietal development by breeders, and help reduce the environmental and economic costs associated with fungicide applications, all of which will have a positive impact on the overall competitiveness and sustainability of the UK arable industry. This will be achieved through collaboration with 13 rust pathology laboratories across 6 continents and industrial support from 6 breeding, agronomy and chemical companies and the HGCA.

Flowering in wheat results in the production of grain that is harvested for human, animal and industrial use. Yield is a product of the number of flowers and the proportion of the flowers that successfully set grain. Wheat yields in the UK are generally high but some varieties show infertility (a low proportion of flowers setting grain) under certain environmental conditions. An example of this problem occurred in the winter wheat variety 'Moulin' in the mid 1980's when poor grain set caused losses to growers of up to 90%. Wheat infertility remains a serious threat because a variety with this weakness may slip through the current trialling system and give a serious yield failure. In addition, lower and less obvious levels of infertility may be suppressing wheat yields. Each 1% loss in fertility is estimated to cost £18m to the UK (i.e. 15mt production at a grain price of £120 per ton). Eliminating alleles that cause infertility will therefore enhance yield and protect against yield failure. Despite the seriousness of this problem very little is known about the genes that make some varieties vulnerable to infertility. To address this, Nickerson-Advanta UK Ltd, RAGT Seeds Ltd and KWS UK Ltd, who produce 95% of the current wheat varietes in the UK, have initiated a project in collaboration with the Home Grown Cereals Authority (HGCA), the Scottish Agricultural College (SAC) and the John Innes Centre (JIC). The companies will provide doubled haploid (DH) populations between parent known to differ in vulnerability to infertility. These popluations will be grown by SAC in sites known to induce reproducible levels of infertility. By combining this with genotying data it will be possible to identify quantitative trait loci (QTL) that control the trait. This will allow breeders to select against these undesirable effects. Five diverse populations will be studied, and a primary aim is to determine if there are one or several genetic causes of infertility. This is important for developing a strategy to combat this problem. Results will be tested in a larger collection of varieties and lines provided by the companies and results will ultimately feed through into new testing regimes that will help prevent 'at risk' lines from reaching the market place.

Doctoral Training Partnerships: a range of postgraduate training is funded by the Research Councils. For information on current funding routes, see the common terminology at https://www.ukri.org/apply-for-funding/how-we-fund-studentships/. Training grants may be to one organisation or to a consortia of research organisations. This portal will show the lead organisation only.