Influence of hydrolyzed animal protein-based biostimulant on primary, soluble and volatile secondary metabolism of Genovese and Greek-type basil grown under salt stress.

• Foliar biostimulant application showed better results on phenolic content. • Biostimulant added to the nutrient solution showed better results on volatile content. • Yield and primary metabolism were less affected by the biostimulant in basils. Basil is susceptible to stressful conditions, of which salinity is a major problem in agriculture, causing significant yield losses. Biostimulants can be used as stress reducers and can be used for sustainable agriculture. Genovese-type 'Marian' basil and Greek-type 'Manos' basil were grown under 100 mM NaCl salt stress conditions and treated with a hydrolyzed animal protein-based biostimulant (as foliar fertilizer and via a nutrient solution). Greek basil yield was positively affected in both biostimulant treatments. The irrigated biostimulant had a positive effect on primary metabolites in Genovese-type basil. Foliar application of the biostimulant resulted in higher glucose and ascorbic acid content (+23.8% and +25.7%, respectively) compared to the salt treatment of Greek basil. Phenolic content increased in both biostimulant-treated cultivars and ranged from +73.3% to +628.9%, depending on cultivar and treatment. Volatile content was most affected by the biostimulant added to the nutrient solution and was 18.5% higher in Greek basil and 111.5% higher in Genovese basil than in the salt treatment. With the results of our study, we have laid the foundation for further studies on the internal quality of herbs and which method of biostimulant application is more suitable for basil production under salinity conditions. [ABSTRACT FROM AUTHOR]