Title: Glutenin alleles in U.S. Pacific Northwest wheat Authors
Submitted to: International Gluten Workshop
Publication Type: Abstract Only
Publication Acceptance Date: July 2, 2009
Publication Date: N/A
Interpretive Summary: Abstract -- no technical summary required.
Technical Abstract: The U.S. Pacific Northwest (PNW), comprised of the states of Washington, Idaho and Oregon, produces about 8 million metric tonnes 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 (HMW) glutenin alleles has not been conducted within each of the important PNW gene pools as represented by released cultivars and unreleased advanced breeding lines. Further, the correspondence of stained bands in SDS polyacrylamide protein gels and DNA molecular markers has not been evaluated for wheats of this region. This study included 226 cultivars and advanced lines; 66 soft white winter (SWW), 23 soft white spring (SWS), 20 soft white club, 19 hard white winter (HWW), 20 hard white spring (HWS), 48 hard red winter (HRW), and 30 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. Based on SDS PAGE, the SWW and SWS had a high proportion of null alleles at Glu-A1 (33 and 57%, respectively). Club wheats, which are known for their very weak and extensible doughs, were 70% null Glu-A1. Sub-unit 1 had a low proportion of representation among the soft wheats: zero (club) to 15% (SWW). Approximately a quarter to half of the soft wheats were 2*. Very few hard red wheats carried the Glu-A1 null (zero HRS, 10% HRW). Similarly, only 5% of HWS were null, whereas 21% of the HWW were null. Among the red and white hard wheats, the proportion of 1 and 2* ranged from about one-third to two-thirds each; 2* was greater in all hard wheat types except HRW. In total,10 of the samples could not be clearly identified for Glu-A1. Over half (56%) of the SWW were assigned sub-unit 7 at Glu-B1, with an additional 24% 7+9. The SWS, however were only 9% sub-unit 7, and 48% 7+9. For both SWW and SWS, sub-units 6+8 were the third most prevalent (15 and 22%, respectively). The club wheats were mostly (65%) sub-unit 6, followed by 6+8 (15%) and 17+18 (10%). Interestingly, both the HRS and HWS types shared a high proportion of 17+18 at Glu-B1 (63 and 70%, respectively). Sub-units 7+9 were the next most prevalent (23 and 15%, respectively). No spring wheats contained a ‘single’ sub-unit (i.e. 6, 7 or 20) at Glu-B1. These allele frequencies contrasted that of the hard winter wheats where 7+9 predominated (35% HRW and 58% HRW), followed by 6+8 or 7+8. Among the HRW, nearly a fifth (19%) contained only one sub-unit (7 or 20). A total of 10% of all samples could not be clearly assigned one of these seven Glu-B1 alleles. At the Glu-D1 locus, most (65%) SWW were 2+12, followed by 20% 3+12. In contrast, the SWS were about half 2+12 and 5+10 (57 and 43%, respectively). Club wheats had a high proportion of 2+12 (80%) with the remainder 5+10. Somewhat as expected, the hard wheats had a high proportion of 5+10 (97, 92, 100, and 58%, HRS, HRW, HWS, and HWW, respectively). From this standpoint, it was somewhat surprising that they were not uniformly 100% 5+10, especially HWW which was 37% 2+12. An additional interesting feature of the Glu-D1 locus in these breeding pools, was the presence of 3+12 in SWW (20%) and HWW (5%); 3+12 was not present in any other types. In terms of overall HMW glutenin haplotypes, the HRS were the most uniform with 50% 2*/17+18/5+10, followed by HWS that were 35% 1/17+18/5+10 and 35% 2*/17+18/5+10. The SWS were 30% null/7+9/5+10; the club types were 30% null/6/2+12. Overall, the winter wheats (SWW, HRW, HWW) were the most variable with no more than 21% sharing the same HMW glutenin haplotype. These results suggest that those wheat types with either more stringent end-use quality requirements or narrower germplasm base have more consistent allele frequency, whereas those types with less stringent requirements and greater breeding activity are more variable. Future work will examine the correspondence of DNA molecular markers for HMW glutenin loci among this same set of wheat varieties.