Foliar Spray of Natural and Synthetic Plant Growth Promoters Accelerates Growth and Yield of Cotton by Modulating Photosynthetic Pigments

Foliar spray of growth promoters significantly ameliorated the harmful effects of environmental warming and nutrient deficiency on growth, development and yield of major field crops. So, the current experiment was carried out to evaluate the potential effects of five growth promoting substances, including Moringa leaf extract, Polydol, Multisol, Classic and Asahi star along with water and no spray on growth indices, dry matter assimilation, seed cotton yield and related traits as well as chlorophyll scores of cotton var. MNH-886 under a semi-arid environment of Pakistan. On average bases, the results indicate that exogenous spray of growth promoters enhanced leaf area index by 20.0–26.0%, growth rate by 15.0–21.0%, dry matter partitioning by 15.0–21.0%, sympodial branches by 22.0–33.0%, harvested bolls by 46.0–48.0%, boll weight by 28.0–30.0% and total chlorophyll contents by 15.0–25.0% relative to control treatment. Due to improved morphological and yield contributing traits, the exogenous spray of promoters also increased the seed cotton yield by 21.0–33.0% and net benefit by 50.0–68.0% as compared to control. In conclusion, the MLE, being a cheaper source, could ameliorate the damages imposed by environmental warming and nutrient deficiency, leading to high cotton productivity. The farmers across the world can get high yield of cotton by foliar spray of MLE.