Effects of Cultural Factors on Early Maturity and Yield of Transgenic Hybrid Cotton Variety

The field experiments were carried out on the farm of Hunan Agricultural University,in 2002 and 2003.The effect of sowing date,planting density and nitrogen applying rate on early maturity and yield of Nongza62,a bollworm-resistant hybrid cotton variety were studied by non-linear regression orthogonal combination optimum design (the 311-design).The results showed:1) The days from emergence to boll opening varied with sowing date and nitrogen applying rate,but it varied little with planting density.2) There were observable effects of the factors on the total fruit nodes,the ratio of bolls retention,total bolls,the lint yield and the rate of lint yield before frost per hm2.3) The average weight of seed cotton per boll would be increased conspicuously as the increasing of nitrogen and decreased as sowing early,but it varied little in different planting density.4) The highest lint yield 2 238.6 kg/hm2 would be obtained at the condition of sowing at April 17~18th,2.25×104 plants/hm2,dressing N 262.5 kg/hm2 under the condition of special ecosystem cultivation,in Hunan.