Fusarium head blight (FHB) of cereals is caused by a number of fungi, chiefly Fusarium species. It is of particular concern because the Fusarium species produce trichothecene mycotoxins (DON, NIV, T2 and HT-2) within grain that are harmful to human and animal consumers. FHB disease poses an increasing threat to the UK wheat and barley crops. New species have appeared and spread in the UK for which climate change may, in part, be responsible. Future predicted climate changes are likely to exacerbate risks of epidemics in the UK. The EU recently set limits for DON and limits for T2/HT-2 are imminent. It is vital that the UK is positioned to be able to comply with this legislation. It is widely recognised that resistant varieties offer the best option to control FHB. All wheat and barley breeders consider it as a major but difficult target for resistance breeding. Incorporation of high levels of resistance to FHB into wheat and barley will be critical to prevent DON, T2, HT-2 and NIV mycotoxin contamination of grain from becoming a major problem for all elements of the UK food and feed chains. Timely application with appropriate fungicides can restrict disease development and mycotoxin accumulation. Under moderate to high disease pressure, however, fungicide application often fails to reduce DON contamination to below EU legislative limits in susceptible varieties such as those currently grown in the UK. Our previous work showed that much of the susceptibility of UK varieties is due to linkage between a gene that affects the height of wheat, Rht2 (also referred to as Rht-D1b) which is in almost all UK varieties, with a gene nearby on the chromosome that increases susceptibility to FHB. This association must be broken to enable breeders to produce FHB resistant varieties with acceptable agronomic characters. The project will produce molecular markers to the region about Rht2 allowing plant breeders to maintain this agronomically important gene in their breeding programmes while selecting against the linked FHB susceptibility factor. This project aims to identify resistance to Fusarium head blight (FHB) in wheat and barley that will function against all the causal fungi associated with this disease. This project will focus on the identification of Type 1 resistance (resistance to initial infection) in wheat and barley. We have developed new tools to characterise so-called 'Type 1' resistance (resistance to initial infection), which is important for preventing infection of wheat and barley against Fusarium species that produce DON mycotoxin and those that produce the more toxic T2 and HT-2 toxins as well as against non toxin producing FHB pathogens such as Microdochium species. Plant breeding companies can immediately use the plant materials, genetic knowledge and molecular markers linked to FHB resistance within their breeding programmes to produce new resistant varieties with good characters for growing as crops in the UK. This project will determine how fungicide application influences disease and toxin accumulation in varieties with different levels of FHB resistance. The project will demonstrate how individual FHB resistances affect the RL disease score, revealing how many, and what forms of resistance are required to ensure that toxin levels in UK grain do not exceed EU limits. The project will identify the components required to establish a sustainable, integrated approach to ensure that toxin levels in cereal grain remain below EU limits. An integrated approach, based on varieties with significantly enhanced resistance and appropriate fungicide application offers the best means to achieve sustainable control of FHB and minimise the risk of mycotoxins entering the food and feed chains.

Dietary fibre (DF) is essential for human health, improving gastro-intestinal function and reducing the risk of a range of chronic diseases (including type 2 diabetes, cardio-vascular disease and types of cancer). However, most UK consumers do not eat DF, with the average daily intake being 17.2 g for women and 20.1g for men, compared with a target of 30g. Cereal products are the major source of DF in the UK diet, with bread alone contributing about 20%. However, the contribution from wheat is limited by the fact that most wheat products are made from white flour, which contains about 3.5% DF compared with 11.5-15.5% in wholemeal. We have therefore identified wheat lines with high DF in white flour, which can be used to develop high fibre wheat lines for UK farmers and products for UK consumers. The proposal will remove the constraints to the development of high fibre lines and products in the UK, by collaborating with four wheat breeders, 2 milling and baking companies and the organisations representing the milling (NABIM) and baking (Federation of Bakers) sectors. This will be achieved in two ways: by providing high fibre pre-breeding lines and molecular makers to wheat breeders, and high fibre lines to millers and bakers to optimise their processes. These advances will be disseminated by the BBSRC Designing Future Wheat programmes and by NABIM and FoB. It will therefore have a fundamental impact on the diet and health of UK consumers.

The aim of this project is to improve stability of the Hagberg Falling Number (HFN), a major quality trait in wheat. HFN is currently sensitive to a number of environmental conditions that reduce the quality of grain and make it unsuitable for bread-making, resulting in severe financial losses to farmers: last year (2004) only 27% of the UK wheat crop grown for bread-making was of acceptable quality, with an estimated loss to farmers of £100 per acre of wheat grown. UK cultivars vary in their susceptibility to low HFN, partly due to the difficulty of applying conventional phenotypic screens to large populations of breeding selections, but some (eg. Option, Malacca) evidently carry adequate genetic resistance. Recommended List scores for HFN rely on the occurrence of appropriate weather conditions to trigger latent susceptibility or overhead irrigation to provoke pre-harvest sprouting (McVittie J & Draper S (1982) or irrigation of standing plots of winter wheat in order to assess varietal predisposition to pre-harvest sprouting. J. Natn. Inst. Bot. 16: 45-48). A key aim of this project is to furnish new tools and biological insights to enable breeders to identify new lines with stable HFN from the available pool of elite UK germplasm. The fact that existing resistant cultivars do not manifest problems with emergence in field sowings indicates that this aim is compatible with prompt stand establishment. Previous research by the applicants has shown that the two most important causes of high alpha-amylase levels in UK grain are pre-harvest sprouting (PHS) and pre-maturity alpha-amylase (PMA). PHS is the result of premature germination of grain in the ear, promoted in susceptible varieties by wet weather in the period between maturity and harvest. The consequent secretion of alpha-amylases into the starchy endosperm results in the deterioration in grain quality that is measured by the HFN test. PMA is less well defined, but is believed to result from inappropriate production of alpha-amylases by the aleurone layer in the crease region of the endosperm, late in grain development. Within the BBSRC financed objectives of this LINK project we intend to study the biochemical and molecular events in the wheat grain that are responsible for reduction of HFN during both PHS and PMA. Molecular genetic information from model species will be used to provide 'candidate genes' associated with germination potential/ endosperm development. These will be used for testing of function during seed development in relation to PHS/PMA. The characterisation of expression characteristics and genetic variation of candidate genes in existing germplasm, and the development of 'smart screens' and validated genetic markers will provide UK wheat breeders with resources to create improved varieties with more stable HFN. This project will address several components of the BBSRC strategic plan objectives for integrative biology and sustainable agriculture, including 'functional and comparative genomics', 'integrative biology-plant', 'transcriptomics', 'whole organism biology' and 'sustainable agriculture'. It will aim to provide a 'pipeline' for the delivery of information gained from studies in model species to tools for use to enhance breeding germplasm, a key recommendation of the recent BBSRC Crop Science Review.