作物品种退化是指在正常的栽培条件下,一个品种种了几年之后,产量逐渐下降,一年不如一年。这种产量下降的表现,常称之谓退化。品种为什么会退化?在这一方面涉及的范围很广,因为人们对退化的含义认识不一致,所以究竟什么品种退化,往往在概念上有些摸糊。真正的品种退化应当是由于品种本身遗传性的改变,或者是品种的适应性发生了变异而造成的产量下降。但我们经常听到的关于肥麦的退化问题,却不完全是这样。有的是由于品种混杂,纯度下降影响了产量;有的是由于发生了病害产量下降;也有的是由于栽培条件不好影响了产量;都叫做肥麦品种退化了。而事实怎样呢? 第一,品种退化与品种混杂是截然不同的两码事。品种退化产量下降,意味着这个品种本身(内因)发生了变异造成的产量下降,而品种混杂产量下降,说明混进来的品 Crop varieties degenerate refers to the normal cultivation conditions, a species planted a few years later, the production decreased gradually, less than a year a year. This decline in the performance of the production, often referred to as degeneration. Why Breeds Degenerate? The range involved in this area is very wide because people are not aware of the meaning of degradation, so it is often conceptually obscure to see what breeds degenerate. Degradation of the real species should be due to the genetic changes of the species itself, or the variety of adaptability has led to changes in the yield decline. However, we often hear about the degradation of fertilizer and wheat, but this is not exactly the case. Some are due to species mixed, the decline in purity affect the yield; some is due to the occurrence of disease yield decline; some are due to poor cultivation conditions affect the yield; are called fertile varieties degenerated. But what about the facts? First, the degradation of varieties and the variety of hybrids are quite different two things. Degraded yield decline, which means that the variety itself (internal) mutation caused by the decline in production, while the variety of hybrid output decreased, indicating the mixed products