Effects of Planting Density on Seed Yield of Three Line Hybrid Cotton

The suitable planting density of female parent is a necessary condition for hybrid seed production yield of three line,in order to make clear the optimum planting density of female parent for obtaining high yield of three line hybrid seed production.Taking transgenic Bt three line hybrid cotton Hanza 301 female Han 750 A as test material,the effects of different planting densities(22 500,37 500,45 000,52 500 and 67 500 plants/hm2)on cotton leaf photosynthetic rate,hybrid seed production yield and yield traits were studied.The results showed that the suitable planting density of female for high yield of three line hybrid cotton were 37 500-45 000 plants/hm2,under the density,the cotton with high leaf photosynthetic rate[19.3-19.6 mmol/(m2·s)],the boll number per plant(22.5-23.1),the number of fruit branch per plant(13.0-13.2),single boll weight(5.1-5.2 g)were all higher,and the seed yield reached 3 922.5-4 027.5 kg/hm2.