Responses to foliar sprays of strawberry variety ‘Portola’ to biostimulants on growth, yield, quality, and bioactive compounds

The acceptance of strawberries in international trade has increased due to their organoleptic qualities, high nutritional value, and richness in antioxidants. This research evaluated the effect of foliar spray with chitosan, brassinosteroids, and thidiazuron as metabolic enhancers on growth, productivity, quality parameters, and bioactive compounds in ‘Portola’ strawberry cultivar in the first year of production. This experiment included six treatments and control with doses of CTS of 100, 300, and 400 mg L-1, of Brassinosteroids (Vitazyme™) 0.5, 1-, and 5-mL L-1 and 0.15 mL L-1 of TDZ (Charger plex™) in applications of these biostimulants alone and combination CTS and BRs. The findings indicated that CTS treatments increased plant length, leaf count, leaf area, and fruit firmness. The joint application of CTS and BRs significantly promotes crown diameter, photosynthetic pigments, carotenoids, fresh and dry weight of roots and aerial parts, and ripening. Applications of CTS 300 mg L-1 and 1 mL L-1 of Vitazyme have shown the highest fruit length, diameter, and weight values. Regarding TDZ, this work showed an increase in crown diameter and in the fresh and dry weight of both the root and the aerial part without significant differences in the content of the chlorophyll and titratable acidity compared to the control. Therefore, it could be safely recommended that foliar application with CTS, BRs, and TDZ can be used as biostimulants to improve the growth, quality and bioactive compounds of strawberry cv ‘Portola’.