Variation at Glu‐1 Loci in Club Wheats

Abstract

AbstractHexaploid club wheats (Triticum aestivum L.) possess unique end‐use quality characteristics and are grouped as a U.S. market subclass of soft white common wheat. Although there have been many reports on associations among high‐molecular‐weight glutenin storage protein (HMW‐Glu) sub‐units with end‐use quality in hard wheats; there has been very limited work done on surveying the club wheats for these subunits. The HMW‐Glu subunits, spike types and grain color were determined for 41 U.S. club wheat cultivars and 79 club accessions obtained from the National Small Grains Collection (NSGC), USDA‐ARS. Accession ‘Harlan JR 35’ (PI 420948), which appears morphologically to be a hexaploid club wheat, was determined to be tetraploid. Egyptian line ‘Maya II‐Tel's’ (PI 422288) was shown to have previously undescribed HMW‐Glu subunits. In the U.S. club wheats the most common HMW‐Glu subunits were: null, 49 % (Glu‐A1); 6, 37 % (Glu‐B1); and 2 + 12, 94 % (Glu‐D1). In the NSGC group the most common HMW‐Glu sub‐units were: 2*, 52 % (Glu‐A1); 7 + 8, 31 % (Glu‐B1); and 2 + 12, 92 % (Glu‐D1). The high frequency of subunits 2 + 12 in the club wheat groups has not been observed previously in numerous surveys of diverse wheat cultivars. The Glu‐B1 subunits 6 (without subunit 8) and 20 which have not been reported in US red wheats, were shown to be common in both club wheat groups. A comparison of diversity indices, including previous studies on HMW‐Glu subunit frequencies on all market classes of wheat, showed that the club groups are as diverse for the Glu‐A1 and Glu‐B1 loci and less diverse for the Glu‐D1 locus.