"Niagara Rosada" table grape cultivated with seaweed extracts: physiological, nutritional, and yielding behavior

Adverse environmental factors, such as heat and drought stress, may impact negatively on the development of grapevines in Brazil, especially for the most important table grape variety, Niagara Rosada. Bioactivators from marine algae offer grower products to help overcome such environmental problems. Seaweed extracts containing organic compounds and bioactive molecules impact beneficial effects to plant physiological, nutritional, and yielding behavior. These effects can be influenced by the seaweed extract used, the methodology of production of the seaweed extracts, and the plant species. A study was carried out on a commercial field, over two seasons, aiming to evaluate the effect of foliar applications of seaweed extracts from Ascophyllum nodosum, Hypnea musciformis, Lithothamnium sp., and Sargassum vulgare at 0.6% on Niagara Rosada physiology, nutrition, and yield. For most evaluations, treatments with seaweed extract improved net photosynthetic rate, stomatal conductance, water use efficiency, and carboxylation efficiency. Leaf content of K, Mg, B, Cu, and Zn was positively affected by foliar application with the seaweed extracts. Yield per plant was affected by foliar application with seaweeds, with higher values in plants treated with seaweed extract from Ascophyllum nodosum followed by Lithothamnium sp.