The effect of Paclobutrazol, growth retardant, on cotton growth and Verticillium wilt (Verticillium dahliae Kleb.).

摘要

In the Tigris Basin, since the profit obtained from cotton is relatively higher with respect to other field plants, cotton growing has been preferred more and continued without crop rotation. Due to lack of crop rotation, Verticillium wilt of cotton (V. dahliae) becomes a significant problem. In this study, through inhibiting or declining Verticillium wilt of cotton, we aimed to increase crop yield by paclobutrazol (PBZ), which is a growth retardant. The dose and time of application of PBZ were determined at Nazilli 87 in 1998 and Sur-Grow SG 501 cotton cultivars in Turkey during 1999. In the research, it was determined that the retardant was effective in reducing the disease. It was also established that in the case of early application and dose increase, the inhibitor was more effective in reducing the disease, however leading to yield lose due to excessive stocky and dwarfing. It was recommended that establishing more plants per unit area will increase the benefit from dwarfing of the retardant mentioned. The yield was increased about 48% in Maras 92 cultivar in 2000, through 0.05 g m-2 application rate supplied after the second irrigation without decreasing the plant density, 20 plant m-2. In conclusion, the application of paclobutrazol at a dose of 0.05 g m-2 was considered suitable after the second irrigation without decreasing the density (through more plants per unit area), when the plant height reaches 40-50 cm..