Effect of Brassinolide on the Growth and Physiological Indicators of Foxtail Millet Under Cyhalofop-Butyl Damage

Cyhalofop-butyl is a gramineous herbicide with good control effect, but it causes some damage when used in foxtail millet fields. Brassinolide (BR) is a type of plant growth hormone that can enhance the stress resistance of crops and plays a crucial role in eliminating and alleviating herbicide damage. To investigate the alleviating effect of BR on cyhalofop-butyl damage in foxtail millet, a study was conducted using Jingu 21 as the test material, combining pot experiments and field experiments. All test treatments were sprayed with cyhalofop-butyl at a concentration of 67.5 g a.i./ha. Three BR spraying times were set: the same day as cyhalofop-butyl spraying (D1), one day later (D2), and three days later (D3). Four BR concentrations were set-0 mg/L (C0), 0.05 mg/L (C1), 0.1 mg/L (C2), and 0.2 mg/L (C3)-resulting in a total of 12 treatments. The results showed that after BR spraying, all agronomic trait indicators of Jingu 21 in both pot and field experiments were alleviated. Compared with the control treatment, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) increased to varying degrees, the malondialdehyde (MDA) content decreased, and the drug damage level was alleviated to different extents. In addition, spraying BR can increase the yield of Jingu 21 under cyhalofop-butyl herbicide damage. The results of all indicators indicated that spraying BR one day after cyhalofop-butyl spraying had the best effect. Therefore, spraying BR at a concentration of 0.1 mg/L can effectively alleviate the damage of Jingu 21 plants. It is recommended that when using BR to alleviate damage in foxtail millet, the application should be spaced one day apart from the herbicide spraying.