BIOSTIMULANT APPLICATION IMPROVES TOMATO (SOLANUM LYCOPERSICUM L.) FRUIT YIELD AND QUALITY DURING THE AUTUMN-WINTER SEASON.

The wide range of components, including amino acids, small peptides, and osmoactive substances (proline, glycine betaine), makes protein hydrolysate a promising biostimulant type, encouraging plant productivity both under smooth or adverse environmental conditions. Plantbased biostimulants can boost growth, yield, quality, and bioactive compounds in a variety of crops. The present study examined the effects of an enzymatic protein hydrolysate formulation (Activeg) applied different times (3, 6, or 9), compared to an untreated control, on production and quality of tomato (Solanum lycopersicum L.) 'miniplum' fruits grown in a greenhouse during the autumn-winter season. This study was carried out at the University of Federico II, Department of Agriculture (40°49' N, 14°20' E). A randomized complete block design was used to distribute the experimental treatments in the field; the obtained data were analyzed using ANOVA. The biostimulant applied 3 or 6 times led to the highest yields, whereas 6 or 9 sprayings enhanced fruit firmness, dry residue, soluble solids and antioxidants. The biostimulant treatment repeated 6 times resulted in the best overall tomato performances in terms of fruit yield, quality and antioxidant content, in the autumn-winter season, which suggests the chance to reduce the chemical fertilizer input, thus contributing to the vegetable crop system sustainability. [ABSTRACT FROM AUTHOR]