Melatonin and mepiquat chloride impact on cotton growth, physiological and yield at different growth stages
Irshad Ahmad, Guanglong Zhu, Guisheng Zhou, Muhammad Usama Younas, Xuebing Yan
Abstract
The supply of exogenous hormones is an important agronomic practices for improving cotton ( Gossypium hirsutum L.) growth and yield. An efficient cropping process is characterized with the foliar applications of melatonin and mepiquat chloride at various developmental periods is a promising alternative to cope with present high cost cotton yield. However, the supply of melatonin and mepiquat chloride in cotton at different growth stages are still less documented in this new planting method. We hypothesized that melatonin and mepiquat chloride might improve the cotton morpho-physiological activities and yield in this new method. Therefore, this study investigates the effect of melatonin and mepiquat chloride on cotton morpho-physiological activities and yield at different growth stages during two years (2019 and 2023). The melatonin and mepiquat chloride (CK 0.00 μ mol L −1 , MT 150 μ mol L −1 , and MC 40 mg L −1 ) were foliar sprayed on two cotton varieties Sikang 1 and Sikang 3 at seedling stage, the bud stage, the blooming stage, and the boll opening stage. The treatment was arranged in randomized complete block design (RCBD). The current results showed that melatonin and mepiquat chloride increased the plant height, leaf number, leaf fresh and dry weight, stem fresh and dry weight, stem diameter, boll length, boll width, dry shell weight, number of seeds boll −1 , lint weight, seed weight, at various growth stages, as compared with control. However, mepiquat chloride treatment reduced the plant height, leaf area and stem diameter for both cultivars during 2023 year. The chlorophyll pigments were increased due to higher antioxidant enzymes activity and lower malondialdehyde content in both melatonin and mepiquat chloride treated plants. Our results suggest that increased accumulation of soluble protein, soluble sugar, sucrose, starch in the leaf with increased photosynthesis and antioxidant enzymes activity at different growth periods, explain the yield increment. Moreover, the melatonin and mepiquat chloride treatments enhanced most of the morpho-physiological activities at four developmental growth period, however, the treatments during boll opening stage performed better. Conclusively, melatonin and mepiquat chloride are required for this new cotton plant method. • Melatonin (MT) and mepiquat chloride (MC) treatments influence the mopho-physiological activities of cotton at various growth stages. • Melatonin enhanced all plant growth attributes, physiological activities, boll measurements, and cotton yield while reducing malondialdehyde levels. • The Yield was attributed to enhanced antioxidant activity and chlorophyll pigment. • Melatonin and mepiquat chloride increased yield and thus required in the plant model.