四、引种的规律引种和其它事物一样,有它的规律性,主要的根据就是:作物的不同品种都有自己的生长发育的特性,它们在生长发育的不同阶段,对于外界的环境条件有一定的要求。如果把甲地的优良品种引到乙地,乙地的优良品种引到丙地,由于自然环境和栽培条件的改变,就不一定仍然和原产地表现的一样良好。大量实践 Fourth, the introduction of the law Introduction and other things, like its regularity, the main basis is that: different varieties of crops have their own characteristics of growth and development, they are in different stages of growth and development, for the external environmental conditions are certain Request. If the fine variety A is introduced to land B and the fine variety B is introduced to land C, the natural environment and cultivation conditions may not be as good as the land of origin. A lot of practice