Abstract
Wheat is expected to be harvested at the optimum time for producing grains that have a high maximum viscosity of amylogram in areas that suffer severe rain damage. Research was carried out to develop a simple and accurate method to predict the optimum harvest time. A positive relationship between the accumulated temperature during ripening and the falling number of grains during the viscosity increment period was observed at several fields in Hokkaido for two years for different cultivars. Using this relationship, we would estimate the optimum harvest time at which the falling number of grains was 300 sec or more. The goodness of fit of predicted values to observed values was significantly high in many locations. Therefore this method could be adapted in growers' fields for harvesting high-quality wheat grains.
