2007 Annual Report 1a.Objectives (from AD-416) The objective of this cooperative research project is to identify heat tolerant wheat germplasm and to identify genes involved in response to heat stress. 1b.Approach (from AD-416) Abiotic stresses of wheat, including drought and heat stress, are major detriments to the yield and quality of wheat grown in the Southern Great Plains of the USA. Conventional and molecular techniques will be utilized to evaluate expression of genes involved in response to heat stress in wheat germplasm. Improved methods for enhancing resistance and/or tolerance to stress will be developed and genes for resistance and/or tolerance to abiotic stress in wheat will be identified to develop lines with increased stress tolerance. 3.Progress Report This report serves to document research conducted under a specific cooperative agreement between ARS and Kansas State University. Additional details of this research can be found in the report for the parent project 5430-21000-005-00D, Genetic Enhancement for Resistance to Biotic and Abiotic Stresses in Hard Winter Wheat. Aluminum (Al) toxicity reduces wheat root growth in low pH soils and causes significant yield losses. However, many cultivars, such as Atlas 66, have tolerance to aluminum toxicity. Mapping populations of recombinant inbred lines were derived from the crosses Atlas 66/Century and Atlas 66/Chisholm. These populations were tested for Al-tolerance by measuring root growth rate during Al treatment in hydroponics and root response to hematoxylin stain after 48 hours of Al treatment. Result identified and validated that one major gene on the distal region of chromosome arm 4DL enhances Al tolerance in Atlas 66. The Al-activated malate transporter (ALMT1) gene was also mapped in this region. Another gene with a smaller effect on Al tolerance was mapped on chromosome 3BL. The objective of a second study was to assess heat tolerance in mature plants (at flowering stage) of 12 cultivars of winter wheat from southern Europe (Mediterranean region). Heat tolerance was assessed by examining the stability of chloroplast membranes (thylakoid membranes), measuring chlorophyll content, and assessing plant growth traits after exposure to 16-day-long heat stress treatment (day/night temperature, 36/30C). Two of the cultivars, ‘Jefimija’ and ‘Proteinka’ showed the highest tolerance to heat stress. Thus, the winter wheat cultivars ‘Jefimija’ and ‘Proteinka’ seem to be good candidates for our future studies on identification of genes of importance to wheat heat tolerance. Progress on this agreement is monitored by regularly discussing program goals, approaches, and results (on-site) and by reviewing annual accomplishments reports.