Foliar biostimulant boost physiological resilience and reproductive growth, increasing cotton yield

Introduction Cotton is a crop of major economic importance, often cultivated under environmental conditions that expose plants to abiotic stresses such as heat and water deficit, which negatively affect physiological performance and yield. Biostimulants have emerged as promising tools to enhance plant resilience and productivity under such conditions. Methods This study evaluated the effects of foliar application of a novel biostimulant “SB”, based on a Glicoligno Lipidic Complex, at different dose rates on antioxidant metabolism, photosynthetic performance, agronomic traits, and boll yield of cotton grown under central Brazil conditions. The treatments promoted significant improvements in physiological efficiency, particularly at higher application rates, with the 2.0 L ha - ¹ dose showing the most pronounced responses. Results and discussion Foliar application of the novel biostimulant SB (Glicoligno Lipidic complex) significantly improved physiological and agronomic performance of cotton grown under central Brazil conditions. SB enhanced net photosynthesis (A) by up to 15.3%, and water use efficiency (WUE) by 12-20.5% ( p > 0.1) across the evaluated cultivars and application times. Also, it increased RuBisCO activity by 9–22.4%, and improved chlorophyll and carotenoid contents ( p > 0.05) by up to 25.2% and 16.3%, respectively. Antioxidant responses were modulated, with hydrogen peroxide (H 2 O 2 ) and malondialdehyde (MDA) levels reduced ( p > 0.1) by up to 12.4% and 14.3%, respectively, indicating reduced oxidative stress. These physiological benefits translated into higher reproductive success, with number of bolls per plant increased by approximately 30% in cultivar C 1 and boll weight increasing by 6–6.3% in C 2 . Overall fiber seed yield was enhanced ( p > 0.05) by 6.9% in C 1 ( p > 0.1) (cultivar 1; FM 911GLTP) and 5.6% in C 2 (cultivar 2; FM974 GLT). The results highlight SB as an effective foliar biostimulant that improves photosynthetic efficiency, stress tolerance, and yield formation, supporting cotton productivity under variable field conditions.