玉米播种一次,年年收获,不需重种。这是国外科研人员正在研究的一个新课题,他们试图利用玉米的野生近亲种大刍草,将多年生的性状培育到普通玉米中去。大多数的大刍草是一年生,其原产地是墨西哥和中美州。早在1921年,第一次发现了多年生的大刍草。1977年,墨西哥瓜达拉哈拉大学的科研人员,在哈利斯科南部地区的两个地点发现多年生大刍草。1978年,墨西哥和美国科研人 Maize sown once a year, without heavy replanting. This is a new topic that foreign researchers are studying. They try to cultivate the perennial traits into common corn by using the wild relatives of maize. Most of the annual grass is an annual, its origin is Mexico and Central America. As early as 1921, perennial herbaceous plants were found for the first time. In 1977, researchers at the University of Guadalajara in Mexico found perennial grass in two locations in southern Jalisco. In 1978, Mexican and American scientists