Abstract
Annual variation of maximum viscosity (MV) of wheat flour and the relationship between MV and the precipitation during the ripening period were studied in order to establish cultivation techniques for producing good quality wheat with high and stable MV in any growth environment. The MV of flour greatly varied with the year, sowing time and cultivar. MV of flour was mainly affected by the precipitation during the late stages of ripening peroid (1–15 days before maturity stage). Especially, the influence of precipitation during the 5 to 6 days before the maturity stage on the MV of flour was large. In addition, MV of Iwainodaichi with high degree of winter habit was higher and more stable than that of Chikugoizumi with low degree of winter habit regardless of years and sowing times. Judging from the above results, improvement of the tolerance to rain damage during the late ripening stage is most important for stable production of wheat with high MV. The selection of the cultivars whose quality is little damaged by the precipitation during the late ripening stage, and early sowing that allows harvest in May with little precipitation, may be effective for producing good quality wheat with high and stable MV.
