Submitted to: Journal of the Science of Food and Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 27, 2005
Publication Date: March 31, 2005
Citation: Morris, C.F., Garland Campbell, K.A., King, G.E. 2005. Kernel texture differences among u.s. soft wheat cultivars. J. Sci. Food Agric. 85:1959-1965. Interpretive Summary: The basis for variation in kernel texture among U.S. soft wheat varieties is largely unknown. One hypothesis for this variation is that the differences are due to minor genetics. This theory was examined in a study that evaluated 30 varieties from the two major U.S. soft wheat regions in a 6 site-year trial in Washington state. Kernel texture and Quadrumat break flour yield were rigorously tested, and it was clearly shown that consistent genetic differences exist among U. S. soft wheat varieties. Based on test results, 4 different variety groupings were established. The next step is to identify the genes that form the basis of kernel texture variation.
Technical Abstract: Kernel texture is a key factor in the quality and utilization of soft wheat (Triticum aestivum L.), yet the variation in kernel texture among U.S. soft wheat cultivars is largely unknown. This study evaluated the following hypothesis: soft wheat cultivars differ in kernel texture due to minor genetic factor(s). Once identified, selected contrasting cultivars could serve as candidates for crop improvement and future genetic studies. To test the hypothesis, kernel texture (SKCS, Single Kernel Characterization System and NIR, Near-Infrared Reflectance) and Quadrumat break flour yield were evaluated for 30 cultivars drawn from the four major U.S. soft wheat regions and sub- classes (eastern and western soft white winter, soft red winter and Club). Cultivars were grown in replicated trials over 6 site-years in Washington state. The results clearly indicated that relatively large, consistent genetic differences in kernel texture exist among U.S. soft wheat cultivars. SKCS and NIR were fairly-well correlated (r = 0.85) and tended to rank cultivars in the same order. However, individual cultivars deviated from this linear relationship and occasionally rankings changed substantially. Trends were observed among the geographical regions and sub-classes, e.g. the first 13 hardest-ranked positions (SKCS) were held by Western cultivars (13 of the 16 total Western cultivars). Quadrumat break flour yield provided an independent assessment of kernel texture and was not correlated with SKCS or NIR hardness. Based on Analysis of Variance and two-dimensional graphical assessment, four distinct cultivar groupings were made. Each group represented contrasting levels of kernel texture (SKCS or NIR) and break flour yield. Identification of the specific underlying gene(s) conferring kernel texture variation among U.S. soft wheats awaits the next phase of research.