WATER IMBIBITION RATE OF WHEAT KERNELS AS AFFECTED BY KERNEL COLOR, WEATHER DAMAGE, AND METHOD OF THRESHING

Abstract

The rate of water imbibition by wheat kernels may be related to preharvest sprouting damage and tempering times during milling. The effects of kernel color and exposure to weather damage on water imbibition rate of wheat (Triticum aestivum L.) kernels, and the effects of field vs. oven drying and hand vs. mechanial threshing on water uptake rate of HY320 wheat and Welsh triticale (X-Triticosecale Wittmack) were investigated. Rates of imbibition were determined by sequential weighings over a 32-h period of 50-kernel samples imbibing water from agar media. In HY320 wheat, the rate was faster for mechanically threshed (0.0117 g g−1 h−1) than for hand-threshed (0.0115 g g−1 h−1) samples. Threshing method did not affect imbibition rate of Welsh triticale kernels (average 0.0141 g g−1 h−1). Rate of germination was significantly greater for mechanically threshed than for hand-threshed Welsh, but there was no significant difference for HY320. Method of drying did not affect kernel water imbibition rate. Rate of imbibition was faster in nonweathered than in weathered wheat (0.0136 vs. 0.0130 g g−1 h−1). In five wheat crosses involving white and red kernel color, rate of water imbibition was not associated with the allele for kernel color. Rate was negatively correlated with kernel weight (r = 0.49**, n = 49) and kernel hardness (r = −0.29*) in the five crosses, and positively correlated with protein content (r = 0.44**). Other undetermined factors accounted for the major part of the genotypic differences in rate of imbibition.Key words: Triticum aestivum L., X-Triticosecale Wittmack, windrowing, kernel water imbibition rate, germination rate