| A pot experiment was conducted to study the effects of two plant growth regulators (AFD and DPC) on the bud-boll number, leaf chlorophyll content, seed-cotton yield and fiber quality of cotton. The results showed that soil water content was an important factor to determine the yield of cotton, the higher, the more. After spraying plant growth regulators, the chlorophyll content of cotton plant was higher than that with no sprays. DPC spray had little influence on bud and boll growth of cotton plant, but it made cotton yield increased and fiber quality decreased under high soil water condition. Spraying AFD resulted in a great influence on bud and boll growth of cotton plant. The changes of bud-boll number tended to gently enlarge first and then become diminished or gradually keep increasing. Spraying AFD had a significantly promoting effect on formation of bolls but an inhibitory effect on the appearance of new buds. This led to the yield of pre-summer bolls to be increased significantly and the yield of autumn bolls to be decreased greatly, consequently causing seed cotton yield decreased and fiber quality improved a little. |