论文部分内容阅读
《新科学家》杂志近期的一篇农业评论文章指出,在上世纪中叶,由于土豆遭到一种流行的凋萎病而失收,曾使大约100万爱尔兰人饿死。1992年在墨西哥发现了迄今最具毒害性的一种凋萎病毒,并于1994年扩散到北美,被命名为P.infestants Us-8。这种P.infestants US-8病毒完全制服了植入土豆以抵抗枯萎病的基因,并且没有任何已知杀真菌剂能控制它。它能迅速变异以与新的抗性基因及杀真菌剂作斗争。 文章指出,仅由少数遗传稳定品种组成的粮食作物易受疾病、昆虫和严酷气候的影响。如像土豆一样,具有遗传一致性的庄稼如小麦、玉米、甘蔗、香蕉和三叶草等在最近几年也已遭到严重破坏。80年代美国中部的香蕉由于受到黑色香蕉叶斑病的袭击,几乎减产一半。 联合国粮农组织(FAO)最近已完成了对世界植物基因资源的一项最全面的评估。这一综合了154个国家的详细材料的336页评估报告所得出的结论是凄凉的:目前全世界所依赖的作物种类太少,成千上万遗传品种已经消失,还有100多万种也将消失,如果不采取紧急措施的话。 FAO在报告中谈到,世界上大约有3万种可吃植物,其中有7000种已被种植或收集用为食物。许多植物经过上千年的种植已发展出极大的遗传多样性。稻子的一个品种——
A recent Agricultural Review article by the New Scientist pointed out that in the middle of the last century, about 1 million Irish people starved to death by the loss of potato suffered a pandemic. One of the most virulent wilt viruses discovered to date in Mexico in 1992 and spread to North America in 1994 was named P.infestants Us-8. This P.infestants US-8 virus completely conquered the genes implanted in potatoes to combat the wilt and did not control it with any known fungicide. It can mutate rapidly to fight new resistance genes and fungicides. The article points out that food crops consisting of only a few genetically stable varieties are susceptible to diseases, insects and harsh climates. Like potatoes, genetically identical crops such as wheat, corn, sugar cane, banana and clover have also been severely damaged in recent years. In the mid-1980s, bananas in the central United States nearly halved their production due to black banana leaf spot attacks. The United Nations Food and Agriculture Organization (FAO) has recently completed one of the most comprehensive assessments of the world’s plant genetic resources. The 336-page assessment report, which combines detailed information from 154 countries, draws a bleak conclusion: there are currently too few types of crops around the world, hundreds of thousands of genetic varieties have disappeared and more than 1 million Will disappear if no urgent action is taken. In its report, FAO said there are about 30,000 edible plants in the world, of which 7,000 have been planted or collected for food. Many plants have developed immense genetic diversity after thousands of years of planting. A variety of rice -