PERSISTENCY OF GRASS AND LEGUME VARIETIES BRED IN THE WARM REGION OF JAPAN - ACHIEVEMENTS OF PLANT-BREEDING REVEALED IN THE COLLABORATIVE RESEARCH BETWEEN JAPAN AND FRANCE -

Field performance of recently bred varieties and leading varieties of three forage species, Dactylis glomerata, Festuca arundinacea and Medi cago saliva was evaluated in Japan and France, and the results reveale d different aspects of plant breeding in the two countries. Japanese v arieties bred in the warm region displayed a high yield in both countr ies and superior persistency under the humid conditions prevailing in Japan. Yield performance of varieties from France was unstable and the ir persistency was low in Japan. These differences in persistency were evidenced by the larger loss of stands of French varieties in later y ears, caused mainly by weed invasion during summer and autumn. Japanes e varieties displayed a higher competitive ability with weeds. It was concluded that through selection for higher yield and regrowth during shortday seasons under humid conditions, Japanese populations acquired a superior competitive ability, and varieties bred in Japan for highe r yield became persistent also as a result of adaptation to the climat ic conditions of Japan. Varieties from France displayed a high resista nce to rust in both countries, and evaluation in Japan confirmed the h igh palatability of a tall fescue variety of France. The emphasis of b reeding work on forage quality in France contrasted with that in Japan and the history of forage use seemed to be an important factor for th e differences.