Zea mays-Derived Protein Hydrolysate and Diverse Application Modes Differentially Compose Crop Production and Fruit Quality of Strawberry Cultivated Under Tunnel

Agriculture is presently facing several ecological concerns related to the upsurging request for premium-value food produced in compliance with natural horticultural tools. The use of natural substances, such as biostimulants, principally protein hydrolysates (PHs), could be useful to maximize overall vegetable plant fitness. However, the mode of application (foliar spray or fertigation) could affect biostimulant efficiency. The current research was conducted to evaluate the effect of a Zea mays-derived PH (Surnan®, SPAA, Pescara, Italy) and its mode of application (foliar spray and/or fertigation) on yield traits, mineral profile, nutritional and functional components, along with NUE of “Florida fortuna” strawberry cultivated under tunnel. The findings showed that the corn-based PH effectively enhanced yield and number of marketable fruits per plant (NMFP) compared with the control (+20.1% and +25.4%, respectively). Fruits from biostimulated plants also showed a higher fruit lightness and ascorbic acid and anthocyanin concentration than fruits from control plots. Furthermore, Surnan® PH increased nitrogen use efficiency (NUE) of strawberry plants. Captivatingly, plants biostimulated via fertigation showed the highest fruit potassium (K) concentration, while those exposed to the foliar spray had the highest fruit phenolic concentration. Generally, our findings recommended that the application of Zea mays-derived PH via foliar spray could be considered a suitable tool to increase functional traits of strawberry grown under tunnel.