The first one is seriously affected cotton. Fusarium wilt and verticillium wilt are the chronic diseases that restrict cotton production. Cotton is also the carrier of pathogens. The pathogens can spread rapidly with cotton. Therefore, cotton varieties with severe wilt disease and verticillium wilt can not be transferred to disease. Light cotton areas, but can not be transferred to disease-free cotton area. The second is the front peach and late autumn peach cotton. Fuchs peaches and late autumn peaches have poor growth, poor maturity, low boll weight, low seed germination, and weak growth. The third is the removal of peach buds of cotton. Some cotton farmers still have a bad habit of robbing peaches for the development of full-fledged peaches. All cotton seeds that have been used for peach buds cannot be grown because they are not fully mature. The fourth is the spraying of ethephon cotton. Although spraying ethephon can promote the early maturity of cotton by 3 to 4 days, the damage to cotton is large, resulting in incomplete development and cannot be planted. Fifth, serious degradation of species. Cotton is an out-of-breed crop. The out-cross rate is about 8%. Some cotton farmers have not changed new varieties for many years. The purity of cotton seeds is only 70% to 80%, and the quality is seriously degraded. Continued use will lead to a reduction in yield and quality. Sixth, it is stored together with pesticides and fertilizers. Some farmers often store cotton seeds together with pesticides and chemical fertilizers in a warehouse. Because of poor ventilation, toxic gases emitted from pesticides and chemical fertilizers can damage the normal physiology of cotton, resulting in a sharp drop in germination rate. Seventh, the cotton that has been stored for a long time. The average germination rate of cotton seeds stored for half a year is more than 80%. In the absence of low-temperature refrigeration equipment, the life span of cotton seeds is inversely proportional to the storage age. That is, the longer the storage age, the shorter the life span of cotton seeds. Eight is the cotton sun drying on the cement drying field. The drying of cotton with high water content on the cement drying field can easily cause the physiological dysfunction of the cotton seeds, and some of the cotton seeds become dumb and lose their ability to germinate. Nine is a cotton that is heavily damaged by machinery. In the finished coated cotton species, the mechanical damage rate should be controlled within 2%. The cotton seeds whose breaking rate exceeds 2% are affected by the drug, which has a great influence on the germination rate. If the rate of breaking seeds is too high, it is not suitable for planting. Ten is a degenerate child. Cotton is often found in large, white hairy white hair and hairless photon, thin hair, green children, thin green hair, and other children, these are degenerative, the upper long fiber is relatively short, poor quality . Using these seeds to sow the resulting offspring, the yield is reduced and the quality of the fiber is reduced. Therefore, a strict selection must be made before sowing to eliminate these seeds. China Agricultural Network Editor