Creation and Analysis of Novel Storage Protein Alleles.

The puroindolines and the high molecular weight glutenin subunits (HMW-GS) are major determinant of wheat flour functionality.  The puroindoline genes puroindoline a and b together reside at the wheat Hardness locus and control whether wheat is soft or hard textured. Hexaploid wheat HMW-GS are encoded by the Glu-A1, Glu-B1, and Glu-D1 loci with each containing two tightly linked genes coding for an x- and a y-type subunit.  Our objective is to better understand the structure/function relationship between puroindolines, HMW-GS and wheat end product quality.  To this end, we created an EMS mutagenized population using the soft spring wheat variety Alpowa.  More than 100 new puroindoline and HMW-GS alleles were generated and analyzed after backcrossing to Alpowa. Seed quality was assessed by grain hardness tests, milling and baking analyses as well as small scale tests of wheat end product functionality.   The results indicate that the novel alleles may shed light on the structural regions of the puroindolines and HMW-GS that are most important to wheat end product quality.  The new alleles also may prove useful as a novel source of allelic variation for wheat breeding programs.