Influence of nitrogen fertilization and foliar application of plant growth retardants and zinc on quantitative and qualitative properties of Egyptian cotton (Gossypium barbadense L. var. Giza 75).

摘要

Field experiments were conducted in 2 successive seasons, at the Agricultural Research Center, Giza, on a clay loam soil to determine the effect of N fertilizer application (107 or 161 kg N/ha), foliar application of plant growth regulators (Pix (mepiquat), Cycocel (chlormequat) or Alar (daminozide) each applied once at 300 ppm, 75 days after sowing) and zinc (0 or 50 ppm, 80 and 95 days after sowing) on the growth, mineral uptake, yield components and fibre properties of Gossypium barbadense cv. Giza 75. Dry matter yield, N and Zn uptake, opened bolls/plant, boll weight, seed index, lint index, seeds/plant and seed cotton and lint yield/ha increased with increasing N and Zn application and foliar application of plant growth retardants. The greatest increases were with the application of mepiquat. Harvesting date was earlier with the application of Zn in season I and mepiquat in season II. Lint percentage and fibre properties were unaffected by fertilizer or growth regulator application, except in season II when mepiquat and chlormequat were applied and the 2.5% span length of fibres increased compared with the control.