畜牧业有着从集约的奶牛业到粗放的肉牛业和养羊业等各种不同的经营管理水平,各地的气候和土壤条件也有很大差异。要应付这一复杂的农业环境,理想的草地应是产草量高、生长季长、持续年限长、耐寒、耐旱、耐病虫害及耐家畜践踏。但没有一个物种具备所有这些特性,因为经过长期的进化每一物种经选择作用后只能适应相当窄的环境条件。目前通过牧草混播,提高了草地的适应性。但不同草种之间的竞争和不协调性给管理带来了很大困难。因此,牧草育种的一项重要工作是在不同种牧草之间进行杂交使不同属或种各自的有益性状充分组合,培育出适应性广泛的品种。 Livestock husbandry has varied management and management levels ranging from intensive dairy industry to extensive beef industry and sheep raising industry. There are also great differences in climatic and soil conditions all over the country. To cope with this complex agricultural environment, the ideal grassland should be high grass production, long growing season, long duration, cold, drought, pests and livestock trampling. However, no species possesses all of these attributes, since after long-term evolution each species has been chosen to adapt to relatively narrow environmental conditions. Currently mixed grass pastures, improve the adaptability of grassland. However, the competition and incompatibility among different grass species have brought great difficulties to management. Therefore, an important task of forage breeding is to cross between different forages so that the beneficial traits of different genera or species can be fully combined to produce a wide variety of adaptability.