Natsukaze, a guineagrass cultivar, was developed in cooperation between the National Grassland Research Institute and Kyushu National Agricultural Experiment Station, and released in 1985. It is the fast guineagrass cultivar bred in Japan. Almost all types of guineagrass perform apomixis, but at the first step of our breeding work, four plants derived from sexual reproduction were found out. Open pollination and selection were repeated three times using these plants. A breeding strain superior in agronomic characters was chosen and fixed by apomixis. Then, its characteristics, regional adaptation and so on were examined by a number of tests. Natsukaze is larger and more robust in plant type, showing more than 2.5 m of height and wide leaves. The average of dry matter yield in 13 sites for a year period was over 1.8 t/ 10 a, compared with 1.3 t of green panic. Although somewhat less persistency, Natsukaze can be used widely as an annual forage grass for hay production in arable land. In addition, Natsukaze demonstrated high resistance to root knot nematodes.