2007 Annual Report 1a.Objectives (from AD-416) The objective of this cooperative research is to identify, characterize and control soilborne pathogens of wheat and barley, such as Rhizoctonia, Pythium, Gaeumannomyces, Bipolaris and/or Fusarium, which cause root and crown rot diseases; to identify the effects of cropping systems on root pathogen population size and diversity, and on disease epidemiology; and to identify useful wheat and/or barley germplasm with performance against root pathogens. 1b.Approach (from AD-416) Root and crown rot diseases will be identified and characterized through a combination of laboratory, greenhouse and field studies. The ecology of root pathogens and effects of cropping system on pathogen population size and diversity and disease epidemiology will be determined using plant pathology, microbiology and molecular biology methods and approaches. Wheat and barley germplasm will be screened for resistance or tolerance to root pathogens in the field and greenhouse. Practical root disease control will be accomplished through a combination of agronomic practices and biological and chemical treatments. Formerly 5348-22000-012-02S (3/2004). Formerly 5348-22000-012-12S (03/07). 3.Progress Report This project is assigned to National Program Plant Diseases, NP 303 This report serves to document research conducted under a Specific Cooperative Agreement between ARS and the University of Idaho. Additional details of the research can be found in the report for the parent project 5248-22000-013-00D, NP 303, Plant Diseases. 1) Production practices to improve yield and reduce root-infection of soilborne fungi: Under dryland no-till grain production, limited water resources and the infection of soilborne pathogens that reduce root mass reduce yield. ARS collaborators at the University of Idaho, Idaho Falls, ID developed a subsoiling practice to increase water infiltration, which was tested at sites in southeastern Idaho. In most years of average or normal precipitation, subsoiling can increase infiltration of precipitation and yield, and reduce the deleterious effects of root-infecting pathogens. . 2)Screening for resistance to Fusarium species: There is little resistance available to root-infecting fungi such as Fusarium culmorum, the predominant Fusarium in southeast Idaho. Collaborators at the University of Idaho established a Fusarium foot rot nursery at the Aberdeen R&E Center, and screened 61 varieties of wheat, 49 varieties of barley, and 39 transgenic lines for resistance. They identified varieties and lines of wheat and barley with higher levels of resistance or tolerance than commercial varieties. Identification of varieties and advance lines with increased resistance or tolerance to Fusarium will contribute to the development of barley and wheat varieties adapted to Idaho conditions that can perform best under dryland conditions where crown and foot rots are prevalent.. 3)Genetics of resistance and tolerance to Fusarium: Tolerance or resistance in wheat and barley to Fusarium depends on environmental factors and physical and physiological factors of the plant and pathogen. Collaborators at the University of Idaho conducted field, growth chamber, and laboratory studies to investigate the genetics of resistance to Fusarium. Results indicated that different varieties and breeding lines can set crown depth independent of planting depth, thereby limiting exposure to the pathogens. Disease ratings increased with planting depth and crown depth, and yield increased with better stands. Disease reaction within a variety may be independent of planting depth, leading to the identification of varieties that have cellular resistance. Mechanisms of resistance and tolerance may be physical (crown depth) or biochemical (cellular resistance), and identification of both characteristics will facilitate breeding of resistant varieties combining both mechanisms. Resistant or tolerant varieties are needed for areas of dryland and irrigated cereal production in southern Idaho where few control options exist and wheat and barley are regularly exposed to high levels of foot rot pathogens. The ADODR monitors the activities of the project by regular meetings with the university collaborator at the university, professional meetings, field days and grower meetings. ADODR also communicates regularly via email and telephone.