Submitted to: Annual National Wheat Industry Research Forum
Publication Type: Proceedings
Publication Acceptance Date: April 8, 1998
Publication Date: N/A
Technical Abstract: The end-use value of a wheat cultivar is greatly affected by the condition of the grain. Test weight is often used to approximate that condition, even though test weight is not well associated with soft wheat milling & baking qualities. Over the past 50 years the eastern US has selected for ever softer wheats. That may be why the test weights of contemporary eastern US soft wheat cultivars are relatively low. The main characteristics that reduce grain condition are shriveled grain and grain that has puffed due to rain/dry cycles. Shriveled kernels have greatly lowered test weight and milling and baking qualities. Quantifying the degree of shriveling is essential to understanding the components of test weight. We developed a method to objectively score the degree of shriveling. The score is based on the independent results of two devices. One is aspiration and the other is the Perten Single Kernel Characterization System (SKCS) instrument. Together, the test weight change due to aspiration and the SKCS kernel weight change due to aspiration indicate the degree of shriveling. Next, there is the phenomenon of puffing (swelling) of kernels when they experience cycles of rain and drying. The seed coat (pericarp) of wheat has several layers that expand when wet. The outer layers fail to return to original size when dried. Puffing lowers test weight, increases softness, and does not effect flour yield. We also used the aspirator and the SKCS to produce a puffing score. The test weight after aspiration and the SKCS hardness index after aspiration were used to indicate degree of kernel puffing. Puffing and shriveling scores produced an excellent and balanced prediction of original test weight.