Effects of several Plant Growth Regulators on the Yield and Fiber Quality of Cotton (Gossypium hirsutum L.)

Abstract

Plant growth regulators (PGR) are used in cotton (Gossypium hirsutum L.) production to balance vegetative and reproductive growth, as well as to increase seed cotton yield and lint quality. Field experiments were conducted with some PGRs to determine their effects on yield and yield components of cotton using cv. ‘Stoneville 453’. The study was conducted at Harran University Agricultural Research and Application Center located in Şanlıurfa, Turkey in 2004 and 2005. Seven commercial PGRs (Pix, Bigtonik, Biozyme® TF, K-Humate, Maxicrop and Biogibb) were sprayed at recommended doses and application time during the study. Experiments were arranged as randomized complete plot design with three replications. Experimental plots consisted of 12 meter long with six rows, 0.70 m row spacing and 0.20 m plant-spacing on row. The results showed that the applied PGRs (except pix) had significant positive effects on the seed cotton yield, plant height, average number of open bolls, number of sympodia, boll weight, lint percentage and seed index and decreased the earliness index. However, fiber length, fiber fineness, fiber strength and fiber uniformity were not affected by the treatments. Higher yields were obtained in Maxicrop, Biozyme® TF and Biogibb treated plots. Therefore, PGRs might be considered a component of cotton growth management to provide higher seed cotton yields.