|PASHA, IMRAN - University Of Agriculture - Pakistan|
Submitted to: International Gluten Workshop
Publication Type: Proceedings
Publication Acceptance Date: 9/15/2009
Publication Date: 12/1/2009
Citation: Morris, C.F., Pasha, I., Beecher, B.S., Bettge, A.D., See, D.R. 2009. Glutenin alleles in U.S. Pacific Northwest Wheat. International Gluten Workshop; p 141.
Interpretive Summary: The U.S. Pacific Northwest (PNW), comprised of the states of Washington, Idaho and Oregon, produces about 8 million metric tons of wheat annually. This region is somewhat unique in that it grows winter and spring wheats, hard and soft wheats, white and red-grained wheats, and club and lax-head (‘common’) wheats. Most types have distinctive end-uses, which are in part related to their gluten-forming proteins. A survey of high molecular weight glutenin subunits (HMW-GS) (‘alleles’) has not been conducted within each of the important PNW gene pools as represented by released cultivars and unreleased elite breeding lines. Further, the correspondence of stained protein bands in SDS polyacrylamide gel electrophoresis (SDS-PAGE) and DNA molecular markers has not been evaluated for wheats of this region. Specific types included here were soft white winter (SWW), soft white spring (SWS), soft white club, hard white winter (HWW), hard white spring (HWS), hard red winter (HRW), and hard red spring (HRS). In commerce, SWW and SWS are co-mingled, as are HWW and HWS. Club is a sub-class of soft white and may include winter or spring-sown types. HRW and HRS are separate classes.
Technical Abstract: This study included 226 commercial cultivars and elite breeding lines from the U.S. Pacific Northwest. Two or more individual seeds of each variety were extracted for high molecular weight glutenin subunits (HMW-GS) and analyzed using SDS-PAGE. Bands were assigned visually and with the aid of image analysis software. Varieties were also analyzed by PCR for several common Glu-A1 and Glu-D1 alleles. Based on SDS-PAGE and visual assessment of HMW-GS, there was a high level of disagreement between/among seeds of the same variety for one or the other Glu1 loci (43%). Digital image analysis of gels with the aid of internal standards improved band assignment (27% of varieties). Good separations with discontinuous distributions were obtained for Ax1 vs. Ax2* and Dy10 vs. Dy12. Molecular markers were evaluated for Glu-A1 AxNull, Ax1 and Ax2*, and Glu-D1 Dx2, Dx3, Dx5, Dy10 and Dy12. Marker-to-protein agreement rates were on the order of 73-91%. HMW-GS composition was variable across market types, although the hard ‘bread’ wheats clearly had a lower proportion of AxNull, and a higher proportion of Dx5+Dy10. Nevertheless, all market types could potentially be improved and made more consistent if desirable HMW-GS haplotypes could be selected for. Lastly, there seems to be the need for a more reliable, less ambiguous means of identifying HMW-GS; a high level of intra-variety heterogeneity may be an issue.