A Two-Year Evaluation of Biostimulant Effects on Yield and Quality Parameters of Tomato Landrace ‘Pizzutello Delle Valli Ericine’ Cultivated Without Irrigation

Abstract

The use of biostimulants in agriculture provides a sustainable and efficient technology to improve resource-use efficiency. Biostimulants may boost vegetative growth, enhancing plant tolerance to biotic and abiotic stress. The tomato (Solanum lycopersicum L.) is sensitive to drought stress, particularly during fruit setting and fruit development stages. In Italy, long-storage tomato genotypes characterised by drought resistance were selected. In this 2-year study, the foliar application of different biostimulants (betaine, seaweed extracts, vegetal protein hydrolysate and animal protein hydrolysate) was evaluated to determine effects on yield and quality of a local tomato landrace (Pizzutello) cultivated in Sicily without irrigation. The highest dry matter (9.9%) and solid soluble content (6.9° Brix) were observed in plants treated with betaine. Plants treated with A. nodosum or animal protein hydrolysate showed the highest potassium concentrations, whereas those supplied with vegetal protein hydrolysate had the highest calcium concentrations. Tomato treated with betaine were found to have the highest nitrate concentrations. The highest marketable yield (13.8 t ha⁻¹) was recorded in plants treated with vegetal protein hydrolysate, with an increase of 17.4% compared to the control plants. The highest unmarketable yield was observed in control plants and in those treated with betaine (1.1 t ha^-1). In conclusion, we can say that each biostimulant had a different effect on the different parameters analysed. Overall, the application of biostimulants has improved tomato growth, productivity and quality in limited water conditions. Our results highlight the potential of biostimulant applications to optimise both the yield and fruit quality of renowned local varieties. This study demonstrated the improvement in the agronomic performance of the Pizzutello tomato, which is particularly significant not only in response to the growing consumer demand for high-quality traditional tomatoes, but also for the enhancement of the technological traits valued by the food industry.