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.

Nitrogen fertiliser is essential to sustain wheat yields but is also an important determinant of grain quality. This is because nitrogen is required for the synthesis of grain proteins, with the gluten proteins forming the major grain protein fraction. About 40% of the wheat produced in the UK is used for food production, particularly for making bread and other baked products. Wheat is also widely used as a functional ingredient in many processed foods, while bread wheat and imported durum wheats are used to make noodles and pasta, respectively. The gluten proteins are essential for these uses, providing visco-elastic properties to dough. Consequently, the content and quality of the grain proteins affect the processing quality, with a minimum of 13% being specified for the Chorleywood Breadmaking Process (CBP) which is used for over 80% of the "factory produced" bread in the UK. The requirement of nitrogen to produce wheat for bread making is also above the optimum required for yield, and farmers may apply up to 50 kg N/Ha above the yield optimum to achieve 13% protein (2.28% N). This is costly with nitrogen fertiliser contributing significantly to crop production, and may also contribute to a greater "nitrogen footprint" in the farmed environment. It may be possible to reduce the requirement for breadmaking wheats, to a limited extent, by optimising the efficiency of nitrogen uptake and use within the wheat plant. However, this will only have limited benefits and a more viable long-term solution is to develop new types of wheat and processing systems which will allow the use of lower protein contents for bread making. We will therefore identify types of wheat which have good and stable breadmaking quality at low grain protein. Genetic analyses of the trait will provide molecular markers to assist wheat breeders while studies of underpinning mechanisms will allow new selection procedures to be used to identify germplasm and select for quality in breeding programmes. We will also work with millers and bakers to establish optimum conditions for processing of wheats with lower protein contents.

Minimal processing adds significant value to fresh produce, however, it also increases its perishability reducing shelf life and leading to waste of the produce and the resources used to grow it. This project is aimed at post harvest discolouration, a significant cause of quality loss in a wide range of fresh produce such as sliced apple, cut cabbage and lettuce. The main issue we are addressing is postharvest discolouration of lettuce in salad packs. UK lettuce production/imports are worth £240m farm gate but the retail value of UK processed salads is £800m. However, Tesco have recently reported that 68% of their salads are thrown away; the situation is similar for other retailers. There is therefore a need to improve postharvest quality to reduce waste and deliver consistently good quality products to consumers. Modified atmosphere packaging can provide control but once the pack is opened oxygen enters resulting in discolouration. Growing conditions also influence postharvest discolouration but are difficult to control in field crops. We are proposing breeding lettuce varieties with reduced propensity to discolour as a way to address the problem. To do this we need to understand the genetics and biochemistry of discolouration. We are building on previous research we have done which identified genetic factors controlling the amount of pinking and/or browning that developed on lettuce leaves in salad packs 3 days after processing. However, we do not know what compounds or which genes are involved and we now intend to find this out by a multidisciplinary project involving three universities; Harper Adams University, Reading and Warwick, a lettuce breeding company, a lettuce grower, a salads processor and the Horticulture Development Company. We have produced a set of experimental lettuce lines which we know show differences in the amount of pink or brown discolouration they produce. We will grow and process these lettuces in a way that mimics commercial production. We will then assess the salad packs for the amount of discolouration developing over 3 days, which is the current best before date for supermarket salads. We can then link this information to the plant's DNA profile to identify genetic factors for discolouration and DNA markers which can be used by plant breeders. The same lettuces will also be analysed for compounds produced by a biochemical pathway called the phenylpropanoid pathway. This is thought to produce the pigments that cause discolouration. We know from other studies in a plant called Arabidopsis the genes which control the phenylpropanoid pathway and we have found the same genes in lettuce. We will see how these genes behave in lettuce plants that produce a lot of discolouration and ones that don't discolour. We will also see how the genes behave under different growing conditions. We can link these gene expression patterns to the amount of pinking and browning to see which genes are the key ones. Once we have done this we can look for naturally occurring versions of the genes which give a reduced discolouration. The compounds produced by the phenylpropanoid pathway influence other things such as pest and disease resistance, taste etc. We do not want to reduce the amount of discolouration by breeding but end up with lettuce susceptible to pests or with poor taste, so we will assess lines which show high discolouration or no discolouration for their resistance to aphids and mildew and for taste to see if there are any differences. There are some compounds produced by the pathway which are colourless but still provide some resistance so by knowing the genetics and biochemistry breeders will be able to carry out smart breeding. We will see if the results for lettuce hold true for other crops by seeing how the key genes behave in apple and cabbage and whether this is related to the amount of browning that develops when they are processed and look for genetic differences in these crops

This proposal for LINK funded project will build on a solid base of work currently underway, funded through existing LINK programmes, BBSRC, directly by industry, the Scottish Government and the NIAB Trust fund. The proposed study will seek to initiate a better understanding of wheat root growth, morphology and functional relationships with nutrient and water uptake. Methods to describe roots in a diverse range of winter wheat types will be implemented in controlled glasshouse conditions and in the field. The project will form the foundation for improving nutrient sequestration and conversion in this important UK crop through initiation of pre-breeding and development of ideal root ideotypes suitable for use in current and future wheat production. The consortium will concentrate on efficient or enhanced use of resources, especially nitrogen and phosphate and will consider interactions with water availability. In addition, the importance of interactions with beneficial mycorrhizal fungi on nutrient sequestration and the negative impact of soil-borne pathogenic fungi on susceptible genotypes will be considered under field conditions. Finally, the potential impact of agrochemical seed coats on root performance will be assessed. Overall, research in root biology leading to increases in nutrient uptake efficiency will contribute to reductions in diffuse pollution and will substantially reduce green house gas emission due a reduction in the use of nitrogen fertilisers in wheat cultivation

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.