Processing Tomato Yield Research Articles

Biochar stimulates plant growth but not fruit yield of processing tomato in a fertile soil

Biochar addition to soil is a promising option for climate change mitigation and is recognized to exert beneficial effects on soil fertility. However, recent meta-analysis documented controversial effects on soil–plant interactions and on crop yields response.The data presented in this paper are the results of a field experiment on a processing tomato crop aiming to enhance the knowledge on the real applicability of biochar at farm scale in a high fertility alkaline soil. The effects of two biochar types on soil properties and on quantitative and qualitative parameters of processing tomato were evaluated. Biochar application significantly increased the soil carbon content, the soil cation exchange capacity and the availability of NH4+, P and K. Moreover, it stimulated plant growth and N, P and base cation contents at harvest, reducing the leaf water potential in the warmer period. These results demonstrate that also intensive cultivations in fertile soil can benefit from biochar amendment.

Winter wheat straw management on subsequent processing tomato yield, quality, economics and nitrogen dynamics

Van Eerd, L. L., Loewen, S. A. and Vyn, R. J. 2015. Winter wheat straw management on subsequent processing tomato yield, quality, economics and nitrogen dynamics. Can. J. Plant Sci. 95: 273–283. The removal of crop residues to meet the anticipated demand for the bioeconomy sector may impact subsequent crop productivity. A field experiment was designed to evaluate the response of processing tomato (Solanum lycopersicum L.) on winter wheat (Triticum aestivum L.) straw management practices of: (1) retaining straw, (2) removing straw, or (3) retaining straw with a fall application of calcium ammonium nitrate at 34 kg N ha−1 to enhance straw decomposition. At two locations in 2006–2009, a split-plot design within a randomized complete block experiment, with wheat straw management as main-plot factor and nitrogen fertilizer (0 and 145 or 224 kg N ha−1) to the tomato crop as split-plot factor. At Ridgetown, marketable and total yield and profit margins were significantly higher with straw retained compared with straw removed treatments (total yield of 74.4 vs. 66.3 Mg ha−1 yr−1, respectively) but the straw retained plus fall N treatment (total yield 72.8 Mg ha−1 yr−1) was not different. However, at Leamington, straw management had no effect on yield or profit margins likely due to the rye (Secale cereale L.) cover crop used in the production system. At both locations, tomato quality (color, pH, soluble solids) was not influenced by straw or N management. Nitrogen fertilizer application to tomato had a significant effect on total processing yield, soil mineral N, and plant N, but wheat straw management had no effect on these parameters and there were no N fertilizer by straw management interactions. Winter wheat straw management did not impact soil N fertility for subsequent crop production. Thus, there may be significant undesired effects of removing crop residues on a subsequent crop yield; however, planting a cover crop may mitigate subsequent yield losses associated with biomass removal.

Using NDVI and guided sampling to develop yield prediction maps of processing tomato crop

The use of yield prediction maps is an important tool for the delineation of within-field management zones. Vegetation indices based on crop reflectance are of potential use in the attainment of this objective. There are different types of vegetation indices based on crop reflectance, the most commonly used of which is the NDVI (normalized difference vegetation index). NDVI values are reported to have good correlation with several vegetation parameters including the ability to predict yield. The field research was conducted in two commercial farms of processing tomato crop, Cantillana and Enviciados. An NDVI prediction map developed through ordinary kriging technique was used for guided sampling of processing tomato yield. Yield was studied and related with NDVI, and finally a prediction map of crop yield for the entire plot was generated using two geostatistical methodologies (ordinary and regression kriging). Finally, a comparison was made between the yield obtained at validation points and the yield values according to the prediction maps. The most precise yield maps were obtained with the regression kriging methodology with RRMSE values of 14% and 17% in Cantillana and Enviciados, respectively, using the NDVI as predictor. The coefficient of correlation between NDVI and yield was correlated in the point samples taken in the two locations, with values of 0.71 and 0.67 in Cantillana and Enviciados, respectively. The results suggest that the use of a massive sampling parameter such as NDVI is a good indicator of the distribution of within-field yield variation.

Biomass, fruit yield, water productivity and quality response of processing tomato to plant density and deficit irrigation under a semi-arid Mediterranean climate

A 2-year study was conducted to examine the impact of deficit irrigation on dry biomass, water-use efficiency (WUE), fruit yield and quality in open-field processing tomato at high plant density in a semi-arid environment. Three irrigation treatments (nil; and 100% (full) and 50% (deficit) restoration of crop evapotranspiration (ETc), respectively) and two plant densities (2.5 (P1) and 5.0 (P2) plants m–2) were studied. Dry biomass and fruit yield per plant were lower in P2 than in P1, but at high plant density the crop compensated for biomass and yield decrease at the plant level. Fruit yield in P2 was greater than that in P1, by 36% in 2004 and 33% in 2005. Water limitation improved quality traits compared with full irrigation. Deficit irrigation, especially in P2, enhanced WUE and allowed a water saving of >45% relative to full irrigation, while keeping high levels of fruit quality. The yield response factor, Ky, which correlates relative fruit yield losses to relative ETc reduction, was higher (0.63) than Kss (0.44), which correlates relative total dry biomass losses to relative ETc reduction, revealing a greater crop sensitivity to soil-water deficit in terms of fruit yield than dry biomass. Therefore, Ky may of use in identifying the plant density at which water productivity is maximised or yield losses are minimised.

A wavelet neural network model for processing tomato yield forecasting

A wavelet neural network model for processing tomato yield forecasting

Optimizing levels of water and nitrogen applied through drip irrigation for yield, quality, and water productivity of processing tomato (Lycopersicon esculentum Mill.)

The main goal of this study was to evaluate the effects of different levels of irrigation water and nitrogen on yield, quality, and water productivity of processing tomato grown in clay-loam soil. Three water levels of pan evaporation (Epan) replenishment applied via drip irrigation (1.00 × Epan, 0.75 × Epan, and 0.50 × Epan) and four N application rates with fertigation (0, 60, 120, and 180 kg N·ha−1) were tested in the sub-humid climate conditions of Turkey during the 2010 and 2011 growing seasons. The highest marketable yields were observed with full irrigation (1.00 × Epan) for each season. Decreasing irrigation rate generally improved dry matter, total soluble solids, total sugars, titratable acidity, lycopene and total carotene, and decreased fruit NO3-N content and fruit total protein content slightly. The highest water productivity was obtained with a moderate soil water deficit (0.75 × Epan). The 180 kg N·ha−1 fertilization rate produced the highest values for marketable yield, fruit size, total soluble solids yield, NO3-N, and total protein content. Increasing N rate also increased the values of fruit total sugars and titratable acidity. Increasing both irrigation and N levels increased the NO3-N and protein contents. The higher lycopene and total carotene values were obtained in the treatments of 60 and 120 kg N·ha−1. Increasing N supply improved the water productivity with the 3 irrigation application ratios. Considering the quantity and quality for the processing and water productivity, the 0.75 × Epan irrigation regime and a 120 or 180 kg·ha−1 nitrogen supply can considered optimal.

干旱区覆膜滴灌条件下加工番茄高产的肥料配施效应研究

在覆膜滴灌条件下，研究了氮磷钾肥的不同配施对加工番茄的肥料效应的研究。结果表明：1) T3(N 300 kg•hm−2 P2O5 210 kg•hm−2 K2O 150 kg•hm−2)、T5(N 300 kg•hm−2 P2O5 105 kg•hm−2 K2O 75 kg•hm−2)、的肥料配比及施用量适合于加工番茄的高产，产量分别达到111,360 kg•hm−2, 111,450 kg•hm−2，但从经济效益分析T5的经济效益最好，每公顷比对照CK(N 0 kg•hm−2 P2O5 0 kg•hm−2 K2O 0 kg•hm−2)净增收2487元。2) 番茄红素含量与钾肥的相关性较高，T4(N 450 kg•hm−2 P2O5 310 kg•hm−2 K2O 225 kg•hm−2)的番茄红素含量最高为126.8 mg• kg−1、CK最低为89.7 mg• kg−1；氮肥和钾肥对可滴定酸的影响高于磷肥；可溶性总糖含量与施N量相关性较高，相关系数达到0.986，T4的含糖量最高为23.3 mg•kg−1，CK最低为18.6 mg•kg−1。In this paper, the effects of NPK matches on the yield of processing tomato were studied under Plastic Mulched Drip Irrigation. The result indicated that 1) The matches of T3 (N 300 kg•hm−2 P2O5 210 kg•hm−2 K2O 150 kg•hm−2), T5 (N 300 kg•hm−2 P2O5 105 kg•hm−2 K2O 75 kg•hm−2) were able to increase yield greatly, which reached 111,360 kg•hm−2, 111,450 kg•hm−2 respectively. But from the aspect of economic benefit, T5 (N 0 kg•hm−2 P2O5 0 kg•hm−2 K2O 0 kg•hm−2) in contrast to CK has the best economic benefit with pure income of 2487 yuan ha−1; 2) The correlation between K and lycopene is quietly close. The highest Lycopene content of T4 (N 450 kg•hm−2 P2O5 310 kg•hm−2 K2O 225 kg•hm−2) is 126.8 mg•kg−1. The minimum of CK is 89.7 mg•kg−1. Influence of N, K on titrable acidity concentration is more obvious than phosphatic fertilizer. The total content of soluble sugar has high correlation with N. The correlation coefficient is 0.986. The highest sugar content of T4 is 23.3 mg•kg−1. The minimum of CK is 18.6mg•kg−1.

Effect of Regulated Deficit Irrigation on Yield and Water Use Efficiency of Processing Tomato (<i>Solanum lycopersicum)</i>

An experiment was conducted to investigate the effect of regulated deficit irrigation (RDI) on yield and water use efficiency (WUE) of processing tomato in an arid climate. The results showed that crop yields of processing tomato were significantly (p<0.05) 11.0%~60.0% higher in the fully irrigated plots than RDI treatments except that subject to low level of RDI at seedling. When subject to RDI fruit number per plant, fruit weight, fruit longitudinal diameter and transverse diameter were the main components contributing to yield increase of processing tomato, while decayed fruit number was the key factor restraining tomato yield improvement. The WUE of processing tomato was significantly improved by 13.4% in RDI plants subject to low water deficit at seedling compared to full irrigation, but no difference (p>0.05) existed between fully irrigated crops and RDI plants subject to water deficit at seedling or late fruiting. However, in comparison with fully irrigated crops WUE was significantly reduced by 16.3%~23.3% in RDI plants subject to water deficits respectively at flowering and full fruiting as well as subject to high water deficit at late fruiting. Therefore, low level of RDI at seedling while full irrigation during flowering to late fruiting could be applied to effectively improve yield and WUE of processing tomato in arid areas.

EFFECT OF DEFICIT IRRIGATION ON THE PRODUCTIVITY AND CHARACTERISTICS OF TOMATO

In order to assess the effect of water irrigation deficit during season on yield and mechanical damage of processing tomato, an open field experiment was carried out in two seasons 2010/2011 – 2011/2012. Four irrigation treatments were studied: (ET1: 1 time potential crop evapotranspiration (ETc), ET2: 0.9 ETc, ET3: 0.8 ETc and 0.7 ETc, ET4). The study investigated the yield and mechanical damage in packing cage under four levels of water requirements. Numerous mechanical impacts on fruit occurred with resulting mechanical damages of 15.9, 9.9, 7.1, and 9.5% for treatments ET1, ET2, ET3, and ET4, respectively. Total productions of tomato were 30.77, 29.50, 28.88 and 25.54 ton/fed, but net productions of tomato were 25.88, 26.58, 26.83 and 23.12 ton/fed for treatments ET1, ET2, ET3 and ET4, respectively. The bruised productions of tomatoes were 4.89, 2.92, 2.05 and 2.43 ton/fed for treatments ET1, ET2, ET3 and ET4, respectively. The net profit values for treatments ET1, ET2, ET3 and ET4 were 68990.7, 68841.5, 68644.2, and 59804.6 LE/fed, respectively. The amounts of water saved from ET2 and ET3 were 163.5 and 327 mm, respectively. The amount of water saved can be used to provide other areas to increase the production and thereby increase the water use efficiency.

Foliar spray application of glucosinolates and essential oils on processing tomato in open field production system

The development of new strategies of integrate pest management to improve processing tomato yield and sustainable quality, are requested by the market. This study was carried out to evaluate the effects of foliar applications of glucosinolates and certain medicinal plant essential oils in open field cultivation management. Tomato yield from plots treated with rosemary oil and glucosinolates resulted, on average, significantly higher, until 28%, than that of the control plots. However thyme and oregano oil treated plots showed statistically lower values. Plant vegetative status, including phytosanitary aspects, had the same trend as the production as showed by the exponential regression between two parameters. Findings allow us to conclude that foliar spray of glucosinolates and rosemary essential oils prove to be highly effective treatments inducing increases of tomato yield through plant health improvement.

Impact of minimum tillage, oat straw management, and chicken manure on soil water content, runoff, erosion and tomato production

Sustainability of vegetable farms in south Uruguay depends on development of farming systems that can arrest soil deterioration. In a context where major constraints exist for irrigation, and rainfall is highly spatial and temporally variable, one of the main causes of yield reduction in deteriorated soils might be the reduction in soil moisture supply capacity. We established an experiment to determine the effect of different tillage systems on soil water content, runoff and erosion at high rainfall intensity, and on processing tomato (Solanum esculentum) yield. We report the results of the first year of the experiment set up in march 2010 at a finesilty Pachic Argiudoll, with four treatments: Minimum Tillage with Cover Crop, planting oat (Avena byzantina) in basins and leaving it as mulch (MTCC); Conventional tillage with Green manure, same than previous treatment but oat biomass is incorporated to the soil through conventional tillage (CTGM); Conventional Tillage with Chicken Manure (CTChM); and Conventional Tillage (CT). Except CT, all other treatments incorporated chicken litter (7.0 Mg ha-1). Soil moisture was measured at 20 cm depth with time domain reflectrometry and at 100 cm depth with a neutron probe. Runoff and sediment loss were measured with a rainfall simulator at 6 mm/min rainfall intensity. Soil water content at 20 cm depth was the highest in the MTCC and lowest in CTGM and CTChM, yielding up to 10% more volume water content. Runoff and soil erosion was less at both treatments with oat, MTCC and CTGM. However, crop yield was the lowest at the MTCC, pointing out the need for extra attention to the fertilization scheme, because plants showed symptoms of N deficit at the beginning of the growth period. Minimum tillage with mulching contributed to conserve soil water, and to reduce soil runoff and soil erosion.

Effect of irrigation on processing tomato yield and antioxidant components

A 2-year (2007 and 2008) open-field experiment was conducted to study the effects of irrigation on the yield parameters and main antioxidant components (lycopene, phenolic compounds, and ascorbic acid) of processing tomato. Two different treatments were applied: some plants were regularly irrigated, and some had their irrigation cut off 30 days before harvest. Both groups were compared with a rainfed control. Daily irrigation volume was calculated from the average daily temperature to reach optimum water supply. Fruits were harvested at the red-ripe maturity stage. The irrigated plants gave a significantly higher yield, and rainfed plants showed a yield loss. Irrigation had a greater effect on the average fruit weight than on fruit number. A seasonal effect was also remarkable, but was not as strong as that of irrigation. A better water supply caused a lower Brix number than that of the rainfed control. In both years, the antioxidant concentrations in tomato fruit showed a decrease with irrigation, except for the ascorbic acid content.

FEASIBILITY ASSESSMENT OF PROTEIN CONCENTRATE FROM TOMATO PROCESSING WASTES AND DETERMINATION OF ITS FUNCTIONAL PROPERTIES

To extract protein concentrate from tomato processing wastes, the chemical composition of different parts of tomato processing wastes including tomato processing waste meal, tomato seed meal, and tomato oil extracted seed meal were determined. Protein concentrates were prepared by alkali extraction and acid precipitation. To propose the optimal condition for obtaining the maximum protein yield, we performed alkali extraction by using NaOH in 20-70ċ and 8-12 degrees of pH. Next, acid precipitation was performed with HCl in 3.3-5.5 degrees of pH. After determining the protein concentration and dissolved protein mass in extract, the optimal condition was obtained at the room temperature (25-27 ċ) and pH=12. The maximum protein yield of tomato processing waste, tomato seed, and tomato oil extracted seed was achieved in the pH of 3.9, 4.1, and 4.1, respectively. The effect of heat treatment during acid precipitation on protein yield and two functional properties including water absorption and oil absorption capacities of protein concentrates were studied at the temperature over the range of 25-100ċ. Results showed that the highest protein precipitate is obtained at higher temperatures. Moreover, the most protein percentage of both tomato processing waste and tomato seed is given in the room temperature while that of tomato oil extracted seed is achieved at the temperature over the range of 70-85ċ. In addition, by increasing the temperature in acid precipitation stage, the water and oil absorption of protein concentrates is increased. Keywords: Tomato processing wastes, Alkali extraction, Acid precipitation, Maximum protein yield, Functional properties

Responses of Fruit Yield and Quality of Processing Tomato to Drip‐Irrigation and Fertilizers Phosphorus and Potassium

Water and nutrient management are essential to achieve high yield and desirable quality attributes in processing tomato (Lycopersicon esculentum Mill.). A 4‐yr field study (2006–2009) was conducted to assess effects of contrasting water management (drip‐irrigation vs. nonirrigation), fertilizer P (0, 30, 60, and 90 kg P ha−1), and K (0, 200, 400, and 600 kg K ha−1) on yields and quality of processing tomato when the optimum N rate of 270 kg N ha−1 was applied. Compared with nonirrigation, drip irrigation increased marketable fruit yield by 127%, total fruit yield by 66%, and fruit size by 32%, while it decreased soluble solids content (SSC) by 19% and lycopene content by 8%, with no effects on dry biomass of stems and leaves (DBSL). Phosphorus addition had no effects on marketable yield and SSC, but increased the DBSL and lycopene content to maximum values at 60 kg P ha−1. Fertilize K rate affected all examined variables but the lycopene content. Increasing K rates from 0 to 200 kg K ha−1 increased marketable fruit yield by 10% and total fruit yield by 9%, but fruit size declined by 3%. Increasing K rates from 200 to 600 kg K ha−1, however, had no effects on yield and fruit size. Fertilizer K rate had no effects on SSC with nonirrigation, but resulted in a linear increase in SSC with drip‐irrigation. The results suggested that, with optimum N supply, K application is required to increase fruit yield and quality of drip irrigated processing tomato.

Effects of deficit irrigation on biomass, yield, water productivity and fruit quality of processing tomato under semi-arid Mediterranean climate conditions

Processing tomato is a high water demanding crop, thus requiring irrigation throughout growing season in arid and semiarid areas. The application of deficit irrigation (DI) strategies to this crop may greatly contribute to save irrigation water. A two-year study was carried out in order to assess the effects of DI upon water productivity, final biomass, fruit yield and some quality traits of open-field processing tomato cv. Brigade in a typical semi-arid Mediterranean environment of South Italy. Four irrigation treatments were studied: no irrigation following plant establishment (V0); 100% (V100) or 50% (V50) evapotranspiration (ETc) restoration up to fruit maturity, 100% ETc restoration up to flowering, then 50% ETc restoration (V100-50). Total dry biomass accumulation was significantly depressed by early soil water deficit in V0; irrigation at a reduced rate (50% ETc) from initial stages (V50) or from flowering onwards (V100-50) did not induce any losses in final dry biomass. The marketable yield did not significantly differ among plots irrigated, but an averaged irrigation water saving of 30.4% in V100-50 and 46.2% in V50 was allowed as compared to V100. Marketable yield was negatively affected by the early water shortage in V0, due to the high fruit losses (>44%). The effects of DI on fruit quality were generally the converse of those on fruit yield. DI improved total soluble solids content, titratable acidity and vitamin C content. Water use efficiency was positively affected by DI, suggesting that the crop does not benefits from the water when this last is supplied to fulfil total crop requirements for the whole season. Yield response factor, which indicates the level of tolerance of a crop to water stress, was 0.49 for total dry biomass ( Kss) and 0.76 for marketable yield ( Ky), indicating that in both cases the reduction in crop productivity is proportionally less than the relative ET deficit. In conclusion, the adoption of DI strategies where a 50% reduction of ETc restored is applied for the whole growing season or part of it could be suggested in processing tomato, to save water improving its use efficiency, minimizing fruit losses and maintaining high fruit quality levels. This aspect is quite important in semi-arid environments, where water scarcity is an increasing concern and water costs are continuously rising.

Simultaneous impact of the different water supply and year type on processing tomato yield

A two year (2008 and 2009) open field experiment was conducted to study the effect of irrigation on the yield parameters and fruit components of processing tomato. Two different treatments were applied: regularly irrigated (RI), irrigation cut-off 30 days before harvest (CO), compared with unirrigated control (RF). The optimal water supply was calculated from average daily temperature. The aims of the study were to investigate the effect of different water supply on yield quantity. The regularly irrigated plant stands gave significantly higher yield, and unirrigated plants showed yield loss.Water supply had strong positive (R2=0.81) effect on marketable yield and average fruit weight (R2=0.78). Linear regression showed, that 46.5 mm more water supply caused 10 t/ha more marketable yield, and 13.4 mm more water supply caused 1 g more in the average fruit weight. The irrigation increased the Brix yield as well.

Humic Substances Generally Ineffective in Improving Vegetable Crop Nutrient Uptake or Productivity

Soil application of humic acid (HA), generally derived from leonardite shale, is a common practice in California vegetable production. Five commercial HA formulations were evaluated for their effects on soil microbial activity, seedling emergence, crop productivity, and nutrient uptake when applied to representative agricultural soils. Two soils differing in organic matter content (8 and 25 g·kg−1) were wetted to field capacity moisture content with solutions of water, nitrogen and phosphorus (P) fertilizer, HA, or fertilizer + HA and incubated aerobically at 25 °C. In the lower organic matter soil, a synergistic effect of fertilizer and HA was observed after 7 days of incubation on both microbial respiration and the amount of phospholipid fatty acids detected; these stimulatory effects were not observed in the higher organic matter soil. In a greenhouse pot study, the effects of HA on seedling emergence, dry mass accumulation, and P uptake of romaine lettuce (Lactuca sativae L.) were evaluated in four soils of low P availability; HA was applied to the soil at a rate simulating a field application of 2.2 kg·ha−1 a.i. HA had no significant effect on emergence rate or percentage, or P uptake, in any soil; plant dry mass was increased in one soil. Field trials were conducted in 2008 and 2009 evaluating the effects of pre-transplant soil application of HA at 1.1 or 3.4 kg·ha−1 a.i. on growth, nutrient uptake, and fruit yield of processing tomato (Lycopersicon esculentum Mill.). In neither year was macro- or micronutrient uptake increased with HA. Similarly, there was no significant HA effect on plant dry mass accumulation or fruit yield. We conclude that, at typical commercial application rates in representative field soils, HA is unlikely to significantly improve vegetable crop nutrient uptake or productivity.

Effects of different emitter space and water stress on yield and quality of processing tomato under semi-arid climate conditions

The objective of the study was to determine the effects of different emitter spaces and water stress on crop yield, such that the tomatoes would be suitable for processing and paste output (Lycopersicon esculentum Mill cv. Shasta). Such variables were also analyzed with respect to crop quality characteristics (e.g., mean fruit weight – MFW, fruit diameter – FD, penetration value of fruit – PV, pH, total soluble solids – TSS, and ascorbic acid contents – AA). The experiment was conducted under ecological conditions typical of the Konya Plain, a semi-arid climate, in 2004 and 2005. Drip irrigation laterals were arranged in such a way that every row had one lateral. Emitters were spaced at 25, 50, and 75 cm intervals in the main plots, while four levels of water supply, irrigation at 7-day intervals with enough water to fill the soil depth of 0–60 cm until capacity was reached (I1), and 25, 50, and 75% decreased water supply levels were applied as subplots of the experiment. Results of the field experiments showed that yield suitable for processing (68.7–72.7 t ha−1) and paste output (12.2–12.9 t ha−1) were obtainable under conditions of I1 application (p < 0.01). MFW, FD, PV, and TSS were significantly affected from treatments (p < 0.05). High stress resulted in the highest soluble solids. The total irrigation water amount and water consumptive use of the mentioned application (I1) were determined as 426 and 525 mm in 2004. In 2005, the total irrigation water amount and water consumptive use of the same treatment were 587 and 619 mm, respectively.

Effects of soil water deficit on yield and quality of processing tomato under a Mediterranean climate

In order to assess the effect of soil water deficit (SWD) during fruit development and ripening, on yield and quality of processing tomato under deficit irrigation in the Mediterranean climate, an open-field experiment was carried out in two sites differing from soil and climatic characteristics, in Sicily, South Italy. Six irrigation treatments were studied: no irrigation following plant establishment (NI); 100% (F = full) or 50% (D = deficit) ETc restoration with long-season irrigation (L) or short-season irrigation up to 1st fruit set (S); and long-season irrigation with 100% ETc restoration up to beginning of flowering, then 50% ETc restoration (LFD). The greatest effect of increasing SWD was the rise in fruit firmness, total solids and soluble solids (SS). A negative trend in response to increasing SWD was observed for fruit yield and size. Tough yield and SS were negatively correlated, the final SS yield under the LD regime was close to that of LF, and 47% water was saved. However, SS seems to be more environmental sensitive than SWD, since it varied more between sites than within site. The variations between sites in fruit quality response to deficit irrigation demonstrate that not only SWD but also soil and climatic characteristics influence the quality traits of the crop.

Processing tomato quality as affected by irrigation scheduling

In Southern Italy the paucity of water is a very important problem and due to the fundamental importance of the water for the processing tomato, in this study the influence of irrigation on processing tomato quality was investigated in the years 2002 and 2003. A hybrid processing tomato ( Lycopersicon esculentum L. Mill cv. Ability) was treated with different water regimes obtained combining amount of water and irrigation interval. The effects of the trials were evaluated taking into account the physical and chemical characteristics of the fruits, as well as the content in antioxidants moieties. Furthermore, the relationship among all the quality parameters and the seasonal amount of irrigation water was evaluated. The results, comparing different water regimes obtained combining amount of water and irrigation interval, gave useful indications on the possibility to improve nutritional tomato quality by reducing irrigation water during tomato cropping. In particular, relatively to the Mediterranean areas of tomato cultivation and to the texture of the soil considered in this study, the best compromise between quality and quantity of the processing tomato fruit was achieved both with the extension of the irrigation interval (L40 or L60) and with the limitation of irrigation volume for the second part of the tomato crop cycle (thesis 100-50). Extending the irrigation interval and limiting irrigation volume for the second part of the tomato crop cycle, appeared to be the best management strategy to optimize the yield and nutritional quality of processing tomato.