近年来，棉花主产区棉铃虫大爆发，抗虫棉经受住了严峻考验，普遍获得了增产增收。在此情况下，不少棉农打算自留自用抗虫棉种，但这种做法千万使不得，这是因为抗虫棉品种本身特性决定的，主要原因有三： 一、自留种的纯度降低，抗虫性能和产量明显下降 棉花属常异交作物，异 In recent years, a major outbreak of cotton bollworm in the main producing areas of cotton has endured a severe test against insect-resistant cotton and generally gained a yield and income. In this case, many cotton farmers intend to retain their own use of insect-resistant cotton species, but this practice must not be allowed, this is because the characteristics of insect-resistant cotton varieties of their own decision, there are three main reasons: First, , Pest resistance and yield decreased significantly. Cotton is often outcrossing crops, different