Segregating hard red winter wheat into dough factor groups using single kernel measurements and whole grain protein analysis

In accordance with the Grain Quality Acts of 1986 and 1990, scientists at Kansas State University are studying the feasibility of implementing a quality-based marketing system for hard red winter (HRW) wheat in the Southern Plains. This research addresses the development of a segregation system that uses the single kernel characterization system and the whole grain near-infrared analyzer to evaluate the milling and baking quality of wheat as a single value called "dough factor". This single value represents the amount of flour-water dough that can be produced from a given unit of wheat. Samples of HRW wheat (approximately equal to 100 per location) were collected at five Kansas country elevators during the 1995 and 1996 harvests. After the dough factor was measured for individual samples, the samples were composited into seven dough factor groups to establish binning and segregation strategies and to explore the relationship between wheat quality measurements and dough factor groups. Results showed that dough factor groups were significantly different from each other and that dough factor groups were related (P < 0.05) to increases in test weight, single kernel weight, single kernel size, flour yield, and mixing time. Although locations showed year-to-year variability for test weight, kernel weight, and kernel size, the differences among dough factor groups for these characteristics across locations were consistent, indicating that the mean values within dough factor groups are similar regardless of location. The lack of significant differences in protein content among dough factor groups was attributable to high variability within dough factor groups between years. High protein values were present in low and high dough factor groups, indicating that protein content alone is not a good indicator of wheat quality. Patterns of differences in wheat quality characteristics among dough factor groups suggest that the seven groups studied can be reduced to three groups: < 107, 107-112.9, > or = to 113. This study demonstrates that dough factor as a segregation and marketing tool is related to single kernel characteristics, differentiates wheats of varying quality, and reflects the end-use value of wheat.