Wheat rusts are a major threat to cereal production worldwide. As is common among rust pathogens, the wheat rusts require two hosts to complete their life cycles; stem and yellow rust undertake asexual reproduction on wheat and complete sexual reproduction on barberry (Berberis), where recombination can lead to emergence of novel genotypes. The eradication of barberry in the UK drove stem rust to almost complete extinction. However, over the past decade, barberry planting has been reinitiated and is advancing at speed in many major wheat growing regions. In the UK, this is largely driven by the habitat conservation programme for the endangered barberry carpet moth, Pareulype berberata. This is worrying because in the same time period we have seen an increasing number of sporadic stem rust epidemics in Europe, including severe outbreaks as far apart as Sweden and Sicily. Here in the UK in our preliminary study, we identified one wheat plant infected by stem rust in 2013 which illustrates the potential for stem rust to infect wheat crops in the UK. Furthermore, in 2017 we recorded for the first time in decades stem rust aecia on barberry in the UK. In parallel our collaborators in Sweden in the same year identified the first sexual population of wheat stem rust derived from barberry. The overall aim of this project is to characterize the composition of rust on Berberis to determine if this mass re-planting could be facilitating the future re-emergence of stem rust in the UK, whilst also enhancing wheat yellow rust diversity. This will provide vital information for the future design and deployment of surveillance and management strategies that fully consider the threat of Berberis. However, it must also carefully balance the desire to minimise the risk of intensifying wheat rust diversity with (where possible) protecting habitat for the barberry carpet moth. The proposed research aims to: (1) define the composition of rust on Berberis in the UK, (2), determine the risk of barberry-derived sexual rust populations to UK wheat and barley production, and (3) develop a UK risk model for wheat rust dispersal from Berberis and associated management actions. This research project will provide a wealth of information regarding the role of the sexual cycle in exacerbating the diversity of cereal rusts. Furthermore, it will provide vital information that will directly inform policy regarding the re-planting programme for Berberis across the UK and identify areas of high risk that should be avoided or (if plants are already present) regularly monitored. Herein, we aim to achieve a careful balance that manages the immediate needs of the farming community, ensures future resilience in UK wheat by accessing the susceptibility of breeding material to wheat stem rust, whilst conserving the biodiversity of UK fauna.

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The supply of fresh fruit and vegetables to the UK consumer is dependent on a secure supply of freshwater, both in the UK and in countries from which we import fresh produce. However, we grow these crops in the most water-scarce parts of the UK and import large volumes from water-scarce countries (such as Israel, Spain, South Africa and Egypt). This means that the fresh fruit and vegetable system is exposed to a range of "water-related risks", including drought and water scarcity, but also poor water quality, changing water regulations and risk to the reputation of retailers if seen to be "contributing to drought". Meanwhile, climate is changing; other demands for water (including the need to leave water in the environment to support the ecosystem) are increasing; and we are all being encouraged to eat more fresh fruit and vegetables as part of a healthy diet. By using case-studies in south and eastern England and South Africa, this project will explore how and where the system is exposed to water-related risk (both now and in the future). It will seek to develop ways in which people and organisations (including growers, retailers, consumers and policy makers) can change their methods of working to reduce the impact of these risks on the security of supply, without causing unwanted impacts on others in the system or the environment. That is, making the fresh fruit and vegetable system more "resilient" to water related risk. The project team involves experts in plant science, agriculture, environmental science, irrigation technologies, applied mathematics, sociology and water politics to ensure a broad view of the issue.

Onion is an important horticultural crop which is cultivated by every agricultural nation in the world and is also the second most valuable vegetable crop in the world behind tomato. Onions are a staple crop in many countries and deliver a range of health benefits including anticarcinogenic, antithrombotic and antibiotic effects. Despite the value of the crop, research into breeding and genetic improvement is limited as few resources such as onion diversity sets, pure breeding lines and genomic information are available. Diseases are one of the major constraints to onion production and one of the most important is caused by the soilborne plant pathogen Fusarium oxysporum. This fungus is diverse and has many different sub-species (formae speciales, f.spp.) which attack various crop plants. In onion, F. oxysporum f.sp. cepae (FOC) can infect plants at any stage causing a 'damping-off' symptom on seedlings and a basal rot on more mature plants and bulbs. This results in severe pre- and/or post-harvest losses and has been estimated to cost farmers in the UK in the region of £11M per annum. As FOC is a soilborne pathogen which produces long-lived spores that survive for many years, control approaches are difficult and have previously relied on the use of soil sterilisation / pasteurisation, drenches with fungicides or seed treatments. This approach has largely been unsuccessful, has undesirable environmental effects and is threatened by legislation governing restrictions in pesticide use. In the absence of effective control measures for Fusarium basal rot, identifying resistance in onion is extremely desirable but so far has been relatively unsuccessful. However, using a highly pathogenic FOC isolate in a rapid screening test we developed using onion seedlings, we have identified onion lines with much higher levels of basal rot resistance than current commercial cultivars. In a collaborative project between the University of Warwick, East Malling Research and the international vegetable breeding company Nickerson-Zwaan, we propose to provide information, tools and resources which will lead to more effective and sustainable control of Fusarium basal rot, primarily through the development of FOC-resistant onion lines. This will benefit a wide range of stakeholders including breeders, growers and other researchers. The main outcomes of the project will be 1) the identification of FOC pathogenicity/effector genes which could be used as markers to distinguish this pathogen from other F. oxysporum f. spp. or non-pathogenic isolates, 2) the identification of FOC resistance loci and associated genetic markers in onion for use in future breeding programmes, 3) the production of new onion populations segregating for FOC resistance and pre-breeding onion lines to enable the development of basal rot resistant onion cultivars for the industry. Growers and the industry will clearly benefit from this research as the deployment of resistant cultivars will give them a more sustainable and attractive option for basal rot control in onion in the future. In addition, DNA markers associated with genes controlling FOC pathogenicity should also provide a platform for developing diagnostic and quantitative tests for the pathogen in soil, onion seed, sets and bulbs which will help farmers make decisions about disease risk and develop management options. Overall this means that the public will benefit from better quality onions grown with reduced pesticide inputs.

Climate change poses one of the greatest risks to future food production both in the UK and globally. Around 72% (17.5 million hectares) of the UK land area is farmed, with 37% of this as productive arable land. In 2017, the UK agriculture sector employed 419,000 people directly and generated Gross Value Added of £10.3 billion each year. The general consensus is that climate change will have both significant positive and negative impacts on UK agriculture, and these will vary depending on geographic region. Climate-related impacts may occur through gradual, long-term change, or as a result of more rapid and stochastic changes triggered by extreme weather events, such as droughts and wet winters. In the short- to medium-term, we expect the growth of certain crops, such as maize, to benefit from longer growing seasons and higher temperatures. However, in the longer-term, changing patterns of rainfall, increased evaporation and reduced water availability will all threaten crop production. Similarly, increasingly wet autumns will constrain agricultural production by adversely affecting the timing of farming operations. These could indirectly result in environmental damage, such as soil compaction and erosion. However, considerable uncertainty remains as to the location and severity of these impacts, and the rate of recovery following perturbations. It remains a research major challenge to disaggregate the impacts of climate change on crop production from many other technological and socio-economic factors affecting yield. This uncertainty and a lack of knowledge have left the UK agricultural sector poorly prepared for a future, changing climate. An indication of this was provided by the significant impact of the 2018 summer drought on yields of many major crops. BBSRC and NERC are currently funding a large national capability research programme "Achieving Sustainable Agricultural Systems, ASSIST" (https://assist.ceh.ac.uk/), with strong support from the farming industry. As part of this programme, the Centre for Ecology & Hydrology has assembled a strong multi- and inter-disciplinary team to develop and test new farming systems. Building on ASSIST, the CROP-NET project aims to scope out the requirements for a robust, real-time crop and grass yield monitoring and modelling service for the UK to provide improved predictions of future climate change impacts. Specifically, we will explore: 1) the feasibility of using Earth Observation data in combination with large volumes of precision yield data collected by the farming industry to provide early warning detection of climate-related risks to crop yields across the UK; 2) the use of fine-scale projections of UK climate under UKCP18 to target locations across the UK that represent the full range of climate change scenarios over the next 30-40 years. This process will consider different climate variables (e.g. temperature, precipitation) at different temporal resolutions (e.g. average summer temperature, drought periods, and heat peaks) that are likely to affect crop growth and yield. In this way, the monitoring of yield will provide data to pick apart the different process by which climate change will affect yields; 3) the key social and economic factors affecting farmer perception of climate change threats, and their willingness and ability to adapt their farming systems in response to this; and 4) the viability of using data from an established, real-time crop yield monitoring network to improve the predictive power of crop growth models to build a demonstrator prediction service, and therefore inform climate adaptation strategies for crop production.