Meta-QTL Aanalysis of Yield Potential in Wheat and Understanding Underlying Physiological Processes.

Genomic tools, particularly molecular markers, are allowing us dissect the genetic control of complex traits in terms of the locations of QTL.  For the last five years or so, we have had a programme of large scale QTL analysis of yield and yield components using recombinant doubled haploid populations to understand the variation still segregating in predominately the Northern European winter wheat pool.  This is being combined with physiological analysis to understand the underlying mechanisms of yield development.  Traits of particular attention are soluble carbohydrate reserves in the stem, leaf area duration, so called ‘stay green’, and nitrogen use efficiency.  QTL were discovered for yield and yield components in all crosses, and correlated with underlying physiological traits. This process of ‘Meta-QTL analysis’ is giving us a picture of the ‘yield dynamics’ of European winter wheats, which is giving us pointers to what allelic variation is available for further yield improvements and which traits should be focused on for future selection.  Furthermore, we are searching for candidate genes underlying the traits through developing near-isogenic lines for fine mapping, using EMS derived mutant populations and TILLING, and by converting ESTs and candidate genes to conserved Orthologous Sequence (COS) markers and mapping back to QTL locations.