目前棉花种子工作中问题较多,有的地方棉种繁育体系没有建立起来或者很不健全,有些社队只种不选,只引不繁,盲目调种,结果有的新品种还没有大面积推广就开始混杂退化,如黑山棉1号有的社队杂株率达20—30%,衣分降低2—3%,绒长缩短2—2毫米。值得引起注意。一、棉种混杂退化的原因棉种混杂退化,是指一个纯度高的优良品种群体中出现了与这个品种不同的异型株,这种异型株不断增加,会使良种群体的平均经济 At present, there are many problems in the work of cotton seeds. Some cotton breeding systems in some places have not been established or are not perfect. Some communes and brigades only do not choose, Promotion began mixed degradation, such as Montenegro on the 1st of some commune fleet rate of 20-30%, 2-3% lower clothing, long shortening of 2-2 mm. Worthy of attention. First, the reasons for the degradation of cotton mixed cotton degradation, refers to a high purity of the elite breeds appeared in this group with different shaped strains, the increasing number of heterotypic strains, will make the average population of elite populations