AbstractAll wheat varieties (106) grown in the U.S. on more than 100,000 acres (38,610 ha) as of the latest (1984) crop variety survey were characterized by sodium dodecylsulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE). The high‐molecular‐weight glutenin subunit (HMW‐GS) band patterns for each variety were assigned the corresponding Payne numbers and theoretical quality scores based on those assignments. The subunit assignments were compared for the different wheat varieties and the five main wheat classes grown in the U.S. Hard red spring (HRS) and winter (HRW) wheats used mainly for breadmaking showed a remarkably high percentage of bands associated with good breadmaking quality. The allele 5+10, which has the strongest association with good quality, was present in 91 % of the hard red spring wheats and 62 % of the hard red winter wheats. Also, 91 % of all HRS and 53 % of HRW wheat varieties had quality scores of 9 or 10 (10 is the highest possible score). Evidently, by selecting for quality through close cooperation with quality testing laboratories, U.S. breeders have unknowingly selected for high quality glutenin subunits in their released varieties.HRS and HRW wheat varieties are normally grown in different environments in time and/or space, accounting to a large extent for differences in protein content (∼2 %) and other quality traits in the two crops. The uniformly high theoretical quality scores of the HRS wheats compared to more variable scores for HRW wheats may help to explain the popular perception that spring wheats have intrinsically higher quality than winter wheats. Admixing grain from variable (some poorer, most good) HRW wheat varieties (due to genetics or environment) has probably also led to the perception of overall lower quality for HRW than HRS wheats.In the soft red winter (SRW) and soft white (SW) wheat classes where the end‐use is typically cookies and cakes, 40 and 90 %, respectively, have the allele 2+12 that correlates with poor bread baking quality. The absence of alleles for good bread baking quality may be predictive of good quality for soft w