Storage Conditions Affecting Increase in Falling Number of Soft Red Winter Wheat Grain.

Falling number (FN) of wheat grain, a measure of preharvest sprouting, tends to increase during storage; however, grain and storage conditions that impact FN changes are poorly understood. Wheat grain samples of varying FN from several cultivars were obtained by artificial sprouting, by incubating wheat stalks, or directly from the field and were used to determine the effects of cultivar, storage temperature, grain moisture content, and initial FN on changes in FN and α-amylase activity. Increases in FN of artificially sprouted grain during storage were affected by temperature but not evidently by grain moisture in the range of 10.0-13.0%. The FN of artificially sprouted grain increased when stored at 5, 23, and 35°C for 20 weeks by averages of 9.4, 24.1, and 34.4, respectively. The influences of storage temperature and initial FN of grain obtained from incubated stalks were different between cultivars when stored for 8 weeks. Wheat grain obtained directly from the field also exhibited significant increases in FN during 8 weeks of storage at 5, 23, and 35°C with average increases of 10.0, 27.1, and 38.5, respectively. The impact of a-amylase activity on the increase in FN during storage was evident only for fieldharvested grain of varying FN. a-Amylase activity exhibited a negative logarithmic relationship (R ² = 0.87) with FN in field-harvested grain. The magnitude of the changes in α-amylase activity varied by cultivar. [ABSTRACT FROM AUTHOR]