The effect of grower defoliant application on cotton (Gossypium hirsutum L.) on some morphological and fiber quality properties

This study was carried out in ten grower fields in Aydın, Efeler, Koçarlı, Söke, Didim and Germencik districts in 2019 production year in order to determine the effect of grower defoliant applications on some morphological and quality properties of cotton. In the study, Gloria cotton variety was used as material. Randomized parcels were conducted according to the trial pattern. In the study, the total number of boll, the number of opened boll and the total number of leaves before the defoliant application; the number of opened bolls after the defoliant application, the rate of opened boll after the defoliant application, the number of green leaves after the defoliant application and the number of dry leaves remaining on the plant, the leaf fall rate, the ginning out-turn, the cotton moisture rate, fiber length, fiber fineness, fiber maturity, short fiber content, fiber strength, fiber elasticity, fiber brightness degree (Rd), yellowness rate of fiber (+b) and trash content in fiber properties were investigated. In the experiment, it has been determined that there is no statistically significant difference between growers' applications in terms of boll ratio, cotton moisture rate, fiber length and short fiber content characteristics after defoliant application. Total number of bolls before defoliant application, number of opened bolls before and after defoliant application, number of leaves before defoliant application, number of green leaves and dry leaves remaining on the plant after defoliant application, leaf fall rate after defoliant application, ginning percentage, fiber fineness. It has been determined that there are statistically significant differences between the applications of the growers in terms of fiber maturity, fiber strength, fiber elasticity, fiber brightness degree, yellowness rate of fiber and trash count in fiber. In the study, it was found that some grower did not perform defoliant application as required. Keywords: Cotton, defoliant, morphological and fiber quality properties