The effect of defoliant application on yield and yield components of some cotton (Gossypium hirsutum L.) cultivars at timely and late sowing

Authors : Hasan HALİLOĞLU, Cevher İlhan CEVHERİ, Vedat BEYYAVAŞ

Pages : 157-164

Doi:10.31015/jaefs.2020.2.5

View : 15 | Download : 8

Publication Date : 2020-06-15

Article Type : Research Paper

Abstract :This study was aimed to assess the effect of defoliant application on yield and yield components of some cotton cultivars at timely and late sowing under Harran Plain conditions in 2017 and 2018 growing seasons. Field trials were arranged employing randomized blocks split-split plots design with 3 replications. In the study, sowing times insert ignore into journalissuearticles values(i.e.10th of May and 10th of June); consisted the main plots, cultivars insert ignore into journalissuearticles values(i.e. Candia and Lima); placed in the sub-plots and defoliant applications insert ignore into journalissuearticles values(i.e. Control and Dropp Ultra insert ignore into journalissuearticles values(600 ml ha-1);); were in the sub-subplots. Each plot was sown with a length of 12 m and 6 rows, with a 70 cm inter-row and 15 cm intra-row spacing. In the trials, the defoliant chemical called Dropp Ultra insert ignore into journalissuearticles values(i.e.120 g Thidiazuron + 60 g Diuron); was used. The application was practiced when the 60 % of boll opened. It was found that Candia and Lima cotton cultivars sown timely gave seed cotton yields of 5296.7 and 5073.3 kg ha-1 respectively, whereas at late sowing gave the seed cotton yields of 4672.5 kg ha-1 and 4545.8 kg ha-1in 2017 and 2018; Candia gave the higher seed cotton yield insert ignore into journalissuearticles values(i.e. 5179.2 in 2017 and 5013.3 kg ha-1 in 2018); than Lima cultivar insert ignore into journalissuearticles values(i.e. 4790.0 in 2017 and 4605.8 kg ha-1 in 2018); in both years. Results indicated that that the defoliant application increased the seed cotton yield comparing control plots. Defoliant application positively influenced the seed cotton yield insert ignore into journalissuearticles values(kg ha-1);, plant height insert ignore into journalissuearticles values(cm);, number of opened bolls insert ignore into journalissuearticles values(per plant-1);, boll weight insert ignore into journalissuearticles values(g); and boll seed cotton weight insert ignore into journalissuearticles values(g);. However, there were no significant effects on the number of bolls insert ignore into journalissuearticles values(per plant-1); and 100 seed weight insert ignore into journalissuearticles values(g);. It was concluded that defoliant application and timely sowing can be recommended for farmers in the region.
Keywords : Cotton, Defoliant, Yield, Yield components, Timely and late sowing