1. Hokkaido Res. Org. Tokachi Agric. Exp. Stn; Shinsei, Memuro-cho Kasai-gun Hokkaido 082-0081 Japan
2. National Institute of Agrobiological Sciences; Kannondai Tsukuba Ibaraki 305-8602 Japan
3. Agric. Res. Dep. of Hokkaido Res. Org.; Naganuma-cho Yubari-gun Hokkaido 069-1395 Japan