INFLUENCE OF DEFOLIANT USE ON COTTON (GOSSYPIUM HIRSUTUM L.) FIBER YIELD AND QUALITY IN MACHINE HARVESTING

Cotton is a globally significant crop whose market value depends primarily on fiber quality.The quality of the fiber directly affects the profit obtained from the product.However, fiber quality is influenced by production techniques, pre-harvest preparations, and harvesting methods.In this study, the effects of different doses and times of defoliant application methods on cotton yield, boll opening, and fiber technological properties were investigated.The study was conducted in a commercial farm in Bismil district of Diyarbakr province in Turkey, at three application doses, two spraying methods (top only and top + inter-row), and three boll opening periods (40%, 60%, and 90%).The analysis of cotton samples collected by workers and taken from the machine basket during harvest was made with the help of the HVI (high-volume instrument) device.According to the results of variance analysis and LSD test, fiber yield (ginning) was not significantly affected by boll opening rate, defoliant dosage, and spray methods (p < 0.05).Except fiber strength (Str), the effect of boll opening rate (defoliation time) on micronaire (Mic), maturity (Mat) and elongation (Elg) were found to be insignificant.Significant differences (p < 0.05) were observed between spray methods based on HVI analysis.