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Long-storage tomato is a drought-tolerant plant traditionally cultivated under no water supply in semi-arid areas of Italy. In 2009, physiological traits of ten “long-storage” tomato lines cultivated under no irrigation were screened for low soil water tolerance. Leaf relative water content (RWC), proline content and leaf transpiration ( E ) were measured throughout the growing season. Instantaneous leaf water use efficiency was also calculated on a single date, as the ratio between net photosynthesis ( A ) and E . Close relationships were observed among the physiological parameters, positive for E vs . RWC and inverse for RWC and E vs . proline. Results indicate that the increase in proline concentration involves a water stress tolerance, and genotypes more sensitive to soil water deficit respond to drought stress through less proline in leaves. Close significant linear relationships (positive with RWC and E , negative with proline) were also found between fruit yield and all the physiological parameters examined. Among them, the most reliable indicator for yield prediction under water restriction was leaf transpiration rate as measured at the flowering stage. The study made it possible to understand the complex relationships between physiological processes, drought tolerance, and plant productivity in long-storage tomato, and to identify those traits that regulate plant physiology under low water availability. [ABSTRACT FROM AUTHOR]

Highlights: [•] Monoecious and dioecious hemp were studied in Mediterranean semi-arid environment. [•] Later dioecious showed the highest aboveground and stem DM yield (tha−1) [•] WUE ranged between 2.73gl−1 in good water and 3.45gl−1 in water stress conditions. [•] Optimum of photosynthetic rate was achieved at 24°C. At 43°C hemp growth ceased. [•] As soil water availability increased, RUE increased and light extinction coefficient (k) decreased. [ABSTRACT FROM AUTHOR]

Side by side biomass productivities, harvesting time (autumn vs. winter) and frequency (annual vs. biennial) of three perennial grasses were compared under northern and southern Mediterranean climates. Miscanthus ( Miscanthus × giganteus Greef et Deu.) was compared to giant reed ( Arundo donax L.) in Catania (37°24′N, 15°03′E), and to switchgrass ( Panicum virgatum L.) in Bologna (44°55'N, 11°45′E). Generally, giant reed produced about 50% higher biomass than miscanthus in Catania. Miscanthus almost halved biomass productivity in the driest year, while giant reed reduced biomass yield by only 30% under the same conditions. In Bologna, miscanthus and switchgrass produced similar amounts of cumulative biomass over 6 years. Switchgrass kept more stable annual yields than miscanthus, which, however, evidenced a higher potential under favorable climate conditions. Autumn harvest significantly reduced biomass productivity and quality (moisture content, ashes, cellulose and hemicellulose), particularly under South Mediterranean climate. In Catania, autumn biomass was 50% (giant reed) to 85% (miscanthus) lower than winter biomass, while in Bologna, autumn cut reduced switchgrass yield by 20%. Biennial harvesting resulted in almost 40% lower cumulative biomass yield than annual cut, after 6 years. [ABSTRACT FROM AUTHOR]

The aim of the present work was to evaluate the effect of soil water availability and nitrogen fertilization on yield, water use efficiency and agronomic nitrogen use efficiency of giant reed ( Arundo donax L.) over four-year field experiment. After the year of establishment, three levels for each factor were studied in the following three years: I 0 (irrigation only during the year of establishment), I 1 (50% ETm restitution) and I 2 (100% ETm restitution); N 0 (0 kg N ha −1 ), N 1 (60 kg N ha −1 ) and N 2 (120 kg N ha −1 ). Irrigation and nitrogen effects resulted significant for stem height and leaf area index (LAI) before senescence, while no differences were observed for stem density and LAI at harvest. Aboveground biomass dry matter (DM) yield increased following the year of establishment in all irrigation and N fertilization treatments. It was always the highest in I 2 N 2 (18.3, 28.8 and 28.9 t DM ha −1 at second, third and fourth year growing season, respectively). The lowest values were observed in I 0 N 0 (11.0, 13.4 and 12.9 t DM ha −1 , respectively). Water use efficiency (WUE) was significantly higher in the most stressed irrigation treatment (I 0 ), decreasing in the intermediate (I 1 ) and further in the highest irrigation treatment (I 2 ). N fertilization lead to greater values of WUE in all irrigation treatment. The effect of N fertilization on agronomic nitrogen use efficiency (NUE) was significant only at the first and second growing season. Giant reed was able to uptake water at 160–180 cm soil depth when irrigation was applied, while up to 140–160 cm under water stress condition. Giant reed appeared to be particularly suited to semi-arid Mediterranean environments, showing high yields even in absence of agro-input supply. [ABSTRACT FROM AUTHOR]