一年生黑麦草(Lolium rigidum 瑞士黑麦草)是南澳大利亚小麦田的一种主要杂草。近二三十年来选择性除草剂已被广泛用来减少其造成的小麦产量损失。利用除草剂防除杂草使得小麦育种者可以选育收获指数较高的品种,这类品种在纯作时产量较高,通常表现矮秆、分蘖力低和直立习性(Donald和 Hamblin 1976),它们的丰产性对除草剂的依赖程度可能更甚于较老的品种类型。近年来杂草对除草剂抗性的广泛发展,以及减少小麦对除草剂依赖性 Annual ryegrass (Lolium rigidum) is a major weed in the South Australian wheat field. Selective herbicides have been widely used in the last two decades to reduce the wheat yield losses they cause. The use of herbicides to control weeds makes it possible for wheat breeders to breed varieties with higher harvest indices such as higher yields at pure cropping usually with dwarfing, low tillering power and erectness (Donald and Hamblin 1976) The high yield of herbicides may be more dependent than the older varieties. The widespread development of weed resistance to herbicides in recent years and the reduction of wheat herbicide dependence