在特拉维夫大学附近的田野里,以色列科学家正在精心培育一小片杂草。这是一个研究项目的中心。他们认为,这个科研项目有朝一日也许能拯救世界免于饥荒。经过一代一代有选择的育种,当今世界谷类作物产量之高,是早先的农民做梦也想不到的。但是,特拉维夫大学谷类作物改良研究所所长艾萨克·沃尔最近说:六、七十年前,世界农业是以300种左右、产量很低的不同作物为基础的,今天的粮食是以仅仅15种主要作物为基础,它们是人工选择,不是自然选择的结果,产量虽然很高,但是遗传基础却十分狭小而有限,抵抗病害的能力很弱。这是很危险的。沃尔说:“当出现一种新的疾病菌株时,它会象草原的野火一样蔓延到成千上万亩土地上。”有些谷 In the fields near Tel Aviv University, Israeli scientists are carefully nurturing a small crop of weeds. This is the center of a research project. They think the research project could one day save the world from famine. Through generations of selective breeding, the high cereal crop yields in the world today are unimaginable for earlier farmers. However, Isaac Wall, director of the Institute of Cereal Crop Improvement at Tel Aviv University, recently said: “Six to seventy years ago, world agriculture was based on about 300 different crops with very low yields. Today’s food is based on The mere 15 major crops are based on artificial selection, not as a result of natural selection. Although the yield is high, the genetic basis is very narrow and limited, and the ability to resist diseases is weak. This is very dangerous. Wall said: ”When a new strain of disease occurs, it spreads like wildfires into thousands of acres of land." Some valleys