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美国草坪型多年生黑麦草(Loliumperenne)种子的销售量从数量很少增加到年销售量为1810万公斤。对于该草在密度、色泽、质地、刈割性、抗病性和抗旱性方面进行的改良工作普遍受到人们的重视。有些品种耐寒性的改进人们对它又有了新的兴趣,因而使得它能在欧州、美国北部和加拿大部分地区得到广泛的应用。草坪型改良品种并不都具有适应北部地区的寒冷条件,因而
Sales of the American lawn-type perennial ryegrass (Lolium perenne) seeds seldom increased from a few to an annual sales of 18.1 million kg. The improvement of the density, color, texture, mowing, disease resistance and drought resistance of the grass has received much attention. The improved cold resistance of some varieties has given rise to new interest in it, making it widely available in Europe, parts of the northern United States and parts of Canada. Turf improved varieties do not all have the cold conditions to adapt to the northern region, thus