LAUSR

Abstract Four hard red bread wheat cultivars with the same high molecular weight glutenin subunit (HMW-GS) composition (1Ax1, 1Bx13, 1By16, 1Dx5 and 1Dy10), developed for each of two production regions (irrigation and dryland) in South Africa, were tested at two representative locations of each region for two consecutive seasons to determine how different genetic backgrounds, locations and seasons influenced the quantity of the HMW-GS expressed, and how this affected baking quality characteristics. Location contributed the most to the observed variation in the bread making quality characteristics. In the irrigation region, subunit 1Ax1 was correlated significantly to most quality traits, especially flour protein and wet gluten content. In the dryland region, significant positive correlations for similar characteristics were expressed by subunit 1Dx5, showing that the influence of these subunits were not constant across the localities. This also highlighted the importance of the x-type subunits in the bread wheat quality breeding programs of South Africa.