Association Mapping of Wheat Genes Resistant to Aluminum Toxicity.

Aluminum (Al) toxicity is a major constraint for wheat production in acid soils worldwide. Aluminum activated malate transporter (ALMT1) has been cloned in wheat and mapped on 4D chromosome of Brazilian origin. Many wheat breeding lines from the US breeding programs showed a high level of Al resistance. Association mapping of Al resistance genes in these lines may facilitate identification of new QTL for Al resistance in US wheat lines and fine mapping of known QTL to identify better markers for breeding application. In this study, a population of 205 elite wheat breeding lines was collected from different US wheat growing regions and evaluated for Al resistance under both field and laboratory conditions. Field experiment was conducted in fall 2007 in an experimental field of Oklahoma State University, Enid, OK to evaluate seedling growth rate under Al stress. The soil pH in the experimental field was under 4.5. Laboratory experiment was conducted to evaluate relative root growth rate and hematoxylin staining of root tips after Al stress. DNA sequence of ALMT1 will be analyzed to identify functional single nucleotide polymorphism markers for the gene. The new markers for Al resistance will be identified and be useful for pyramiding different QTL/genes for enhanced Al resistance in wheat cultivars.