YIELD, PHYSICO-CHEMICAL TRAITS, ANTIOXIDANT PATTERN, POLYPHENOL OXIDASE ACTIVITY, AND TOTAL VISUAL QUALITY OF FIELD-GROWN PROCESSING TOMATO CV BRIGADE AS AFFECTED BY WATER STRESS IN MEDITERRANEAN CLIMATE

BACKGROUND: The ‘processing tomato’ is an important source of some natural antioxidants (vitamin C, carotenoids, flavonoids, phenols). The nutritional contents of the tomato depends on environmental and agronomic factors, with the irrigation playing a key role in influencing the nutritional value of the fruit. In order to better understand the physiological mechanisms which regulate the response of processing tomato to water stress, a research was carried out in a typically semi-arid Mediterranean environment, in which yield, physico-chemical traits, antioxidant pattern, polyphenol oxidase activity, antioxidant activity, and total visual quality were considered in fruits of tomato cv. ‘Brigade’ field-grown under no irrigation, as compared to the conventional fully irrigated crop. RESULTS: The stressful conditions in V0 negatively affected the total yield and fruits were approximately the 20% smaller than those produced in V100. Nevertheless, they exhibited an increase of firmness (+27%), TS (+23%) and TSS (+5%). The dynamic balance between the antioxidant pattern and PPO activity under water stress conditions allowed to obtain fruits with a 12% increase in antioxidant activity, due to a decline of PPO activity (-48%) and a raise of vitamin C content (+20%) and total phenols (+13%).CONCLUSION: It is possible to manage water stress conveniently by applying water saving irrigation strategies, in order to promote quality and nutritional properties of tomatoes, contributing also to save water. This is a relevant aspect in ‘processing tomato’ cultivation in semi-arid environments, where both cost and availability of irrigation water represent a rising problem in agricultural activities.