INFLUENCE OF PROTEIN SEGREGATION ON THE QUALITY CHARACTERISTICS OF BIGGAR AND GENESIS CANADA PRAIRIE SPRING WHEAT

The influence of protein segregation on the quality characteristics of Biggar, a Canada Prairie Spring Red wheat cultivar, and Genesis, a Ca nada Prairie Spring White wheat cultivar has been evaluated using 1989 , 1990 and 1991 harvest survey samples. Protein segregation had a stro ng influence on most physical parameters and processing characteristic s all three years. However, the dopes of the regression equations of p rotein content to values for each quality test exhibited heterogeneity between years. For both wheat cultivars, test weight and kernel weigh t gave consistently high negative correlations to protein content, ind icative of less kernel plumpness at high protein content. The resultin g lower endosperm content of the higher protein segregates was reflect ed by higher wheat ash content, and lower flour yield in 2 of the 3 yr . The milling performance of the higher protein segregates was further diminished by consistently high positive correlations of flour grade color to protein content, indicative of diminishing flour brightness. Flour ash content was not related to protein content for either cultiv ar, indicating that endosperm ash content was not related to protein c ontent. Flour starch damage, which is directly related to kernel hardn ess, decreased in response to protein content for both cultivars, with the effect being more pronounced for Genesis. Farinograph dough devel opment time, stability and water absorption increased with increasing protein content. Baking water absorption and loaf volume showed highly significant positive correlations with protein content. However, baki ng strength index, a measure of loaf volume on a constant protein basi s, decreased with increasing protein content for both cultivars in 2 o f the 3 yr. These data demonstrate that marketing Canada Prairie Sprin g wheat at specified protein levels would facilitate specific customer requirements by optimizing particular quality attributes and improvin g uniformity between commercial shipments.