水稻是我省的主要粮食作物.水稻的生产,每年从种到收,一年复一年,一代接一代,总是处于不断的变化之中,不是变好,就是变坏。如果不对它加以控制,或者控制的方法不好,良种就会变坏,这就是人们常说的品种混杂退化,引起产量下降。例如湘东,推广至今,才十年之久,由于没有采取有效的留种技术,造成湘东严重混杂退化,七高八矮,早早晚晚,参差不齐,简直不象 Rice is the main food crop in our province, and the production of rice grows from plant to plant year after year, year after year and generation after generation. It is always in constant change, either changing or deteriorating. If you do not control it, or control the method is not good, bad seeds, which is often said that the variety of hybrid degradation, causing decline in production. For example, in eastern Hunan, it has only been ten years since it was popularized. As a result of the lack of effective technology for seed-keeping, it has caused serious mixed degradation in the eastern part of Hunan Province.