Biostimulants to Improved Tree Physiology and Fruit Quality: A Review with Special Focus on Sweet Cherry

Due to the increasing global population and the continued need to sustainably increase agricultural production, the agricultural sector requires innovative strategies to increase productivity and efficiency in the use of resources. Biostimulants have emerged as new, promising, and environmentally friendly products to promote the overall sustainability of production systems. Humic and fulvic acids, protein hydrolysates, seaweed extracts, chitosan and other biopolymers, inorganic compounds, beneficial fungi, and bacteria are widely accepted categories of biostimulants, with proven potential in improving plant growth, increasing crop production, and quality of the final product. Some of them also have the capacity to enhance nutrient uptake and improve stress tolerance of the crop. Sweet cherry is a highly appreciated fruit, with a significant economic value, linked to production yield and quality attributes influencing consumer acceptability. However, this fruit presents several undesirable characteristics, such as physiological disorders (e.g., fruit cracking) and a short shelf-life. Several approaches are used to enhance not only sweet cherry production, but also cherry quality, with the latest efforts being placed in biostimulants. The present review focuses on the most recent findings on the use of biostimulants in sweet cherry production.