A two-year (2010 and 2011) open field experiment was conducted to study the effect of drip irrigation and seasonal variation on the yield parameters and main bioactive components, carotenoids (mainly all trans, cis lycopene, and β-carotene), polyphenols (chlorogenic acid, caffeic acid, gallic acid, quercetin, rutin, naringin, etc.), and tocopherols of processing Strombolino F1 cherry tomatoes. The irrigated plants (STI) gave a higher marketable yield (61% and 101% respectively), and rain fed plants showed a yield loss. Water supply had a strong positive (R2=0.98) effect on marketable yield in 2011, but weak (R2=0.69) in 2010. In both years, the antioxidant concentration (all carotenoids, total polyphenols, tocopherols) showed a decrease with irrigation. Water supply affected the composition of carotenoids to a considerable extent. The optimum water supply treatment gave a lower proportion of lycopene than the rain fed control (STC) treatment. We observed significant negative correlation between rutin concentration and irrigation. The α-tocopherol concentration was significantly higher in STC treatments. Irrigation negatively influenced antioxidant concentrations of cherry tomato fruits, but higher yield could account for the concentration loss of individual fruits by higher antioxidant production per unit area.

Measurement of physiological traits can be used to monitor plant water status, for irrigation scheduling or to predict the expected yield in open-field production of vegetables. This study evaluates the changes in stomatal conductance, chlorophyll fluorescence (Fv/Fm), relative chlorophyll content (SPAD), and canopy temperature at different stages of development of processing tomato to show their relationships with the yield and quality under well-irrigated, deficit irrigated, and non-irrigated conditions. Under non-irrigated conditions, during flowering with fruit setting and early fruit development the highest canopy temperature, lowest stomatal conductance, and Fv/Fm were measured, while the SPAD value was the highest. Under this condition, the correlation between the SPAD value, fruit weight, and marketing yield was positive, but it was negative with the total soluble solid (°Brix). During flowering with fruit setting, under deficit irrigation conditions a close significant positive correlation was found between the SPAD value and the fruit weight, marketing yield, and vitamin C content of fruits. During this period, under regularly irrigated conditions, the SPAD, Fv/Fm, and canopy temperature related to stomatal conductance. Stomatal conductance had significant influence on yield and quality under non-irrigated and well-irrigated conditions while the SPAD value and canopy temperature had significant influence on under deficit irrigated conditions.

Changes of thermoluminescence characteristics as well as the O2-evolving capacity was analysed in chloroplasts isolated from Nicotiana benthamiana infected with pepper and paprika mild mottle viruses and their chimeric hybrids. The electron transport activity in thylakoids of virus-infected plants was inhibited and could be restored by adding DPC or Ca2+ which indicated that the virus infection altered the oxygen-evolving complex. In thermoluminescence characteristics of plants infected with either viruses, the first well defined response was a shift in the peak position of the B band from 20 °C to 35 °C corresponding to S3(S2)QB- and S2QB- charge recombinations, respectively, which showed an inhibition in the formation of higher S states in the water splitting system. Simultaneously, a new band appeared around 70 °C due to chemiluminescence of lipid peroxidation. Further progress of the viral infection dramatically decreased the intensity of bands originated from charge recombinations with a concomitant increase of the band at 70 °C indicating the general oxidative breakdown of injured thylakoids

Four experiments were carried out in 2010 and 2011 to determine how cultivation period (spring or autumn), harvest season (summer or autumn), and plant water status (irrigated or rainfed) influenced content and composition of broccoli cultivar Parthenon F1 with respect to sulforaphane and phenolics under field conditions in Gödöllő, Hungary. Sulforaphane content was significantly higher in the autumn harvests, regardless of irrigation treatments. Harvest season also influenced total phenolics content, with the highest values occurring in the spring season. Harvest season also affected trolox equivalent antioxidant capacity (TEAC) and this capacity was also the greatest in spring. Caffeic acid glucoside was a major phenolics component in both spring and autumn season harvests. The season and irrigation related changes in other phenolic component contents were also characterised in this study.

During the vine ripening of tomato fruits (Solanum lycopersicum L.), the change in antioxidant content and color was studied under two different solar exposures. An experiment was carried out in 2008 and 2009 to determine how color evolution, surface temperature, and antioxidant content of tomato fruits were influenced by fruit position and exposure on trellised tomato plants. Trellised rows were oriented so that non-shaded fruits were subjected to full solar irradiation from 0900 hr to 1600 hr, whereas shaded fruits were completely shaded during the same time period. A significant difference (P = 0.001) between fruit surface temperatures of shaded or non-shaded fruits was observed. The more direct solar irradiation the fruits were exposed to, the higher the fruit surface temperatures increased. At 1400 hr, only the average temperature of non-shaded fruits was significantly higher (7.0 and 9.3 °C in 2008 and 2009, respectively) than the air temperature. At the end of the ripening process, color change of non-shaded fruits showed significantly higher CIELab hue compared with shaded fruits. A close negative correlation (R2 = 0.51) was detected between the hue color parameters and the cumulative fruit surface–air temperature difference of non-shaded fruits, but in the case of shaded fruits, there was only a weak (R2 = 0.29) correlation. Solar exposure had a great effect on the antioxidant content of tomato fruits. A higher fruit surface temperature resulted in significantly less lycopene and more polyphenols and ascorbic acid content in tomato fruits.

Two experiments were carried out in 2010 to determine how cultivation period/harvest season, plant water status/irrigated, or rainfed and foliar sulfur supplementation influences the yield, sulforaphane, phenolics content, and polyphenol composition of broccoli cultivar Parthenon. Yield was significantly higher in the fall harvests. Foliar sulfur treatment induced earliness in irrigated broccoli in the fall harvest season of main florets by 44%. Sulforaphane content was higher in the fall harvests regardless of treatments. Harvest season also influenced total polyphenol content with the highest values measured in the spring season. Sulfur treatment in combination with irrigation increased total polyphenol content by 24% in spring and this change was statistically significant. Harvest season also affected trolox equivalent antioxidant capacity (TEAC) values with the highest values (4.3 mmol·kg−1) also measured in spring. In the irrigated treatment alone or irrigated treatment combined with sulfur treatment, spring season values were higher by 24% and 11%, respectively, compared with fall values and the difference between treatments was significant. Caffeic acid glucoside was one of the major phenolic components in both spring and fall season harvests, whereas ferulic acid glucoside could only be detected in spring florets. From the measured phenolic components, gallic acid content was the only one that was significantly raised by foliar sulfur supplementation in both spring and fall harvests in irrigated or rainfed treatments. Maximum gallic acid values (7.1 to 7.2 mg·kg−1) occurred in the irrigated combined with foliar sulfur treatment of the fall harvest in side and main florets, respectively. The season, irrigation, and foliar sulfur supplementation were related changes in other phenolic component contents and are also described in detail.

Open field experiments were conducted to investigate the effects of plant growth promoting rhizobacteria (PGPR) biofertilizer on processing tomato, grown under three different irrigation regimes. The field effectiveness of rhizobacteria inoculation on total biomass, yield, water use efficiency (WUE), carotenoid, and ascorbic acid production was examined in 2015 and 2016. The experimental design used was randomized block and the number of replications was four for each treatment. There were three different irrigation regimes: rain-fed control (RF), deficit water supply (WS50), and optimum water supply (WS100), which was delivered by drip irrigation in accordance with daily evapotranspiration (ETc). The test was performed on the Uno Rosso F1 processing tomato hybrid. Red fruit were measured at harvest in August and high-performance liquid chromatography (HPLC) was used for analysis. We evaluated yield quantity and total carotenoids and their composition (lycopene and β-carotene) depending on water supplement in 2 years. The marketable yield varied between 14.7 t·ha−1 and 126.9 t·ha−1 depending on treatment. The average soluble solids content (SSC) of the treatments ranged from 3.0 to 8.4. The total carotenoid yields of the treatments ranged from 0.8 to 40.4 kg·ha−1 and the average lycopene yield of the treatments ranged from 0.6 to 34.1 kg·ha−1. The effect of PGPR treatment was clearly positive for harvested yield, but this effect only prevailed under irrigated conditions.

Open field experiments were conducted to investigate the effects of plant growth-promoting rhizobacteria (PGPR) (Phylazonit MC®) as a biofertilizer on processing tomato cultivar var. Uno Rosso F₁, grown under three different regimes of water supply. Field effectiveness of rhizobacteria inoculation on total biomass production, yield and water use efficiency, were examined in 2015 and 2016. Seedlings were inoculated with 1% liquid solution of Phylazonit MC® (Pseudomonas putida, Azotobacter chroococcum, Bacillus circulans, B. megaterium; colony-forming unit: 10⁹ CFU/mL) at sowing and planting out by irrigation. There were three different regimes of water supply: rain-fed control (RF); deficit water supply (WS50) and optimum water supply (WS100); the latter was supplied according to the daily evapotranspiration by drip irrigation. Total aboveground biomass (shoot and total yield) and red fruits yield were measured at harvest in August, in both years. Total biomass changed between 32.5 t/ha and 165.7 t/ha, the marketable yield from 14.7 t/ha to 119.8 t/ha and water use efficiency (WUE) between 18.5 kg/m³ to 32.0 kg/m³. The average soluble solids content of the treatment combinations ranged from 3.0 to 8.4°Brix. Seasonal effects were significant between the two years with different precipitation, which manifested in total biomass and marketable yield production. PGPR increased WUE only in WS50 in both years, while under drought stress and higher water supply, the effect was not clear. The effect of PGPR treatment on marketable yield, total biomass and WUE was positive in both years when deficit irrigation was applied and only in the drier season in the case of optimum water supply.