Agronomical, physiological and fruit quality responses of two Italian long-storage tomato landraces under rain-fed and full irrigation conditions

Drought is the major environmental stress that adversely affects crop productivity in the Mediterranean region. Adopting water saving strategies, such as deficit irrigation or even no irrigation (rain-fed) and using drought-tolerant genotypes and/or landraces may represent effective tools to save water without substantial reduction of yield. An experiment was conducted in two consecutive growing seasons (2013 and 2014), to assess soil water content and matric potential of soil, physiological parameters, growth, yield and fruit quality of two Italian long-storage tomato landraces: "Locale di Salina 6" (LS; 2013 and 2014) and "Piennolo del Vesuvio" (PV; 2014) under rain-fed (RF) and full irrigation (FI) conditions. Leaf water potential, CO2 assimilation, stomatal conductance, photosynthetic efficiency and growth were moderately impaired under rain-fed conditions, while intrinsic water use efficiency slightly increased. The marketable yield of LS in both growing seasons, and PV in 2014 under RF conditions was slightly reduced (by 6%) as compared with the FI treatment, indicating a drought tolerance of both landraces. In the 2014 experiment, the marketable yield was significantly higher by 55% in PV than in LS landrace. When averaged over landraces, the fruit quality traits in particular fruit dry matter, total soluble solids and total ascorbic acid contents increased by 21, 33 and 55%, respectively under RF compared to FI. The results can play an important role in selecting tolerant genotypes for use under limited water supply in order to save water and improve fruit quality without affecting the crop productivity.