Bio-stimulants and its influence on growth and yield of millets: A review

Bio-stimulants are a diverse group of substances and microorganisms which when applied to plants or soil stimulate natural processes to enhance nutrient uptake, stress tolerance and overall plant growth and development. They are classified mainly as acids which include humic substance and amino acid substances, microorganisms which include beneficial fungi and bacteria, seaweed extracts. Bio-stimulants plays an important role in enhancing soil health, mitigating abiotic stress and improving plant resilience to environmental challenges such as drought, salinity and disease. In recent years, there has been a growing interest in bio-stimulants as sustainable alternatives to traditional agricultural practices driven by their ability to improve crop productivity while reducing reliance on synthetic inputs. Bio-stimulants enhance millets growth and yield by stimulating root development, improving nutrient uptake efficiency and promoting physiological processes like photosynthesis and stress tolerance. Current challenges and opportunities in bio-stimulant research emphasizing the need for standardized testing protocols and knowledge dissemination to support their widespread adoption in sustainable agriculture. This review provides an overview of the various types of bio-stimulants including humic substances, seaweed extracts and beneficial microorganisms and the influence of different bio-stimulants on the growth and yield of millets.