生产上应用的优良小麦品种。经过多年种植以后.生产力往往下降,其主要原因是退化.造成退化的原因一般有:①脱粒时机械混杂;②部分植株产生天然异交;③栽培条件和自然条件的影响.一个小麦新品种开始推广时.一般说来,比较“纯”.形态性状、生态性状一致。但是每个个体之间仍存在一定遗传性的差异,它们受到外界环境的影响.开始逐渐朝着适应或不 Production of good wheat varieties. After many years of planting, productivity tends to decline, the main reason is degradation. The causes of degradation are generally: ① threshing mechanical confusion; ② natural outcrossing of some plants; ③ cultivation conditions and natural conditions. A new wheat variety begins In general, the more “pure.” Morphological traits, ecological traits. However, there are still some genetic differences between individuals, they are affected by the external environment began to gradually adapt to or not