Abstract: To explore the possibility of replacing early-maturing varieties with medium early-maturing varieties at cotton planting region of Poyang lake,two representative cotton varieties of medium early-maturing variety Ganmianza No.1（C₁） and early maturing variety Zhongmiansuo425（C₂） were planted at three sowing date （A₁.April 28, A₂.May 10, A₃.May 26） and two densities （B₁.67 500 plants/hm², B₂.90 000 plants/hm²） using the crack zone design in 2018, and the effects of sowing date and density on yield, yield characteristics and fiber quality of cotton were studied. The results showed that the seed cotton yield of all treatments were from 2 513.5 to 3 072.0 kg/hm², and the yields of A₁B₁C₁ and A₁B₂C₁ were relatively high. The yield of A₂B₂C₂ was the lowest, and the difference between the treatments of A₃ was not significant. Sowing date had a significant effect on fiber quality. The quality of cotton fiber treated in A₃ was better than that of A₁ and A₂. In summary, the medium early-maturing varieties should be suitable for late sowing （before the end of May） at cotton planting region of Poyang lake, and as long as the density is appropriate and reasonable chemical regulation, they can grow and develop through their own automatic regulation mechanism to get high yield without affecting fiber quality, and can be used instead of early maturing varieties.

Key words: cotton, sowing date, density, varieties maturity, yield, quality, cotton planting region of Poyang lake