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 cultivar Stoneville 453. The study was conducted in 2004 and 2005 at the Agricultural Research and Application Centre of Harran University located in Şanlıurfa, Turkey. During the study, seven commercial PGRs (MC, NAP, BIGIB, KH, MCROP and BIGIBER) were sprayed at recommended doses and appropriate application periods. Experiments were arranged as randomized complete block design with three replications. Experimental plots consisted of six rows, each having 12 m length, row spacing was 0.70 and intra-row spacing was 0.20 m. The results showed that PGRs (except PC) had statistically significant positive effects on the seed cotton yield, plant height, number of open boll, number of sympodia, boll weight, lint percentage and seed index and that they decreased the earliness index. However, fibre length, fibre fineness, fibre strength and fibre uniformity were not affected by the applications. Higher yields were obtained in MCROP, BIGIB and BIGIBER treated plots. Therefore, PGRs might be considered a component of cotton growth management, which is effective on providing higher seed cotton yields.