Fresh Market Tomatoes Research Articles

Cherry and Fresh Market Tomatoes: Differences in Chemical, Morphological, and Sensory Traits and Their Implications for Consumer Acceptance

The tomato commercial groups cherry and fresh market, mainly classified by fruit size, have clearly segregated markets. We aimed to estimate the variation within and between these groups and to analyze factors that impact consumer acceptance. To this end, we studied the chemical profile (dry matter, sugars, acids) and fruit morphology (Tomato Analyzer) of 63 accessions grown in 2 environments (open air/soil culture; greenhouse/soilless culture). To identify traits underlying consumer preferences, we used a trained panel for quantitative descriptive sensory analyses and consumer surveys on a subset of genotypes. Our results confirm the higher content of reducing sugars (fructose, glucose), soluble solids, dry matter, and glutamic acid in the cherry group and the important effects of environment and genotype-by-environment interactions on fruit quality traits. The diversity within cherry for chemical composition is 1.4-fold to 2.1-fold that of fresh market. Differences in fruit morphological traits (weight, shoulder height, height/width relation) were highly related to fruit size, but no differences between groups were found for the internal structure of the fruit (locular relative content). Consumers value sweetness, glutamic acid, titratable acidity, and juiciness in cherry, and sweetness and taste intensity in the fresh market group. The implications for plant breeding are discussed.

Evaluating anaerobic soil disinfestation and other biological soil management strategies for open-field tomato production in Florida

AbstractIn the search for alternative practices to chemical soil fumigation (CSF), anaerobic soil disinfestation (ASD) has proven to be a promising tool for soil-borne pest management and crop production improvement. The ASD treatment with composted poultry litter (CPL) and molasses (M, a labile carbon source) was identified as an effective approach for a biologically based soil disinfestation system in tomato (Solanum lycopersicum L.) production in Florida. However, environmental and food-safety concerns are associated with animal manure-based amendments, which led to the exploration of composted yard waste (CYW) as a potential substitute for CPL in ASD application. In this study, field trials were conducted in Citra and Immokalee, FL to examine the effects of ASD using CYW, CPL and M compared with a commercially available microbial amendment system on root-knot nematodes, weeds, fruit yield and quality of fresh-market tomato. Treatments included (1) ASD with CPL (11 Mg ha−1) and M (6.9 m3 ha−1) (ASD0.5), (2) ASD with CYW (26.9 Mg ha−1) and M (CYW1 + M), (3) ASD with CYW (13.5 Mg ha−1) and M (CYW0.5 + M), (4) Soil Symphony Amendment (SSA), (5) CYW (26.9 Mg ha−1) alone (CYW1) and (6) a combination of CYW1 + SSA, in comparison with (7) untreated control and (8) CSF (Pic-Clor 60 at 224 kg ha−1). Cumulative soil anaerobiosis was greater in ASD0.5 compared with all the other treatments. The root-knot nematode gall index ratings on the tomato crop were significantly lower in CSF, ASD0.5, CYW1 + M and CYW0.5 + M than untreated control in Citra. Although CYW1 and SSA alone had a moderately suppressive effect on weed coverage and root-knot nematodes, their positive impact on crop performance was limited when used alone. ASD0.5, CYW1 + M and CSF had significantly higher marketable and total fruit yields than untreated control in both locations, while all treatments showed promising results in the Immokalee trial in comparison with untreated control. In general, few differences in major fruit quality attributes were found. Although using CYW in ASD was not as effective as CPL in creating soil anaerobic conditions, the enhanced crop performance in CYW1 + M and CYW0.5 + M suggests the potential of using CYW as an alternative source of organic amendment in combination with M to achieve benefits similar to those obtained with CPL-based ASD.

Effects of Real-time Location-specific Drip Irrigation Scheduling on Water Use, Plant Growth, Nutrient Accumulation, and Yield of Florida Fresh-market Tomato

Florida is the largest fresh-market tomato (Solanum lycopersicum L.)–producing state in the United States. Although vegetable production requires frequent water supply throughout the crop production cycle to produce maximum yield and ensure high-quality produce, overirrigation can reduce crop yield and increase negative environmental consequences. This study was conducted to evaluate and compare irrigation schedules by a real-time and location-specific evapotranspiration (ET)-based SmartIrrigation Vegetable App (SI) with a historic ET-based schedule (HI). A field study was conducted on drip-irrigated, fresh-market tomato during the Fall of 2015 and Spring of 2016 on a Florida sandy soil. The two scheduling methods (SI and HI) were evaluated for irrigation water application, plant biomass accumulation, nutrient uptake and partitioning, and yield in open-field tomato production. Treatments included 100% HI (T1); 66% SI (T2); 100% SI (T3); and 150% SI (T4). Treatments were arranged in a randomized complete block design with four replicates per treatment during the two production seasons. In both seasons, depth of irrigation water applied increased in the order of T2 < T3 < T1 < T4. Total water savings was greater for T3 schedule compared with T1 schedule at 22% and 16% for fall and spring seasons, respectively. No differences were observed among treatments for tomato biomass accumulation at all sampling periods during both seasons. However, T3 resulted in significantly greater total marketable yield compared with other treatments in both seasons. The impact of irrigation application rate was greater in fruit and leaf nitrogen accumulation compared with that of stem and root biomass. Based on the plant performance and water savings, this study concludes that under a sandy soil condition, a real-time location-specific irrigation scheduler improves irrigation scheduling accuracy in relation to actual crop water requirement in open-field tomato production.

Acylsugar amount and fatty acid profile differentially suppress oviposition by western flower thrips, Frankliniella occidentalis, on tomato and interspecific hybrid flowers.

Tomatoes (Solanum lycopersicum L.) have been bred to exude higher amounts or different types of the specialized plant metabolites, acylsugars, from type IV trichomes. Acylsugars are known to deter several herbivorous insect pests, including the western flower thrips (WFT), Frankliniella occidentalis (Pergande); however, all previous studies investigated the effect of acylsugars on leaves, or acylsugar extracts obtained from leaves. In spite of the WFT predilection for flowers, there is a gap in knowledge about flower defenses against thrips damage. This is especially important in light of their capacity to acquire and inoculate viruses in the genus Orthotospovirus, such as Tomato spotted wilt orthotospovirus (TSWV), in flowers. Therefore, we turned our attention to assessing thrips oviposition differences on flowers of 14 entries, including 8 interspecific hybrids, 5 tomato lines bred for specific acylsugar-related characteristics (type IV trichome densities, acylsugar amount, sugar moiety and fatty acid profile), and a fresh market tomato hybrid, Mt. Spring, which only produces trace amounts of acylsugars. Our results show that the density of the acylsugar droplet bearing type IV trichomes is greatest on sepals, relative to other flower structures, and accordingly, WFT avoids oviposition on sepals in favor of trichome-sparse petals. In concordance with past studies, acylsugar amount was the most important acylsugar-related characteristic suppressing WFT oviposition. Certain acylsugar fatty acids, specifically i-C5, i-C9 and i-C11, were also significantly associated with changes in WFT oviposition. These results support continued breeding efforts to increase acylsugar amounts and explore modifications of fatty acid profile and their roles in deterring thrips oviposition. The finding that acylsugar production occurs and reduces thrips oviposition in tomato flowers will be important in efforts to use acylsugar-mediated resistance to reduce incidence of orthotospoviruses such as TSWV in tomato by deterring virus transmission and development of thrips vector populations in the crop.

Fine Mapping of the brachytic Locus on the Tomato Genome

Mechanization of farm work is increasingly demanded for the current system of fresh-market tomato (Solanum lycopersicum) production. One essential element for the adoption of mechanical harvest of fresh-market tomatoes is modification of plant architecture so that the crop can be grown without staking. To address this in the current production system, the stem length should be reduced. The tomato brachytic (br) locus has been shown to be a primary source of reducing stem length. To improve the effectiveness of marker-assisted selection (MAS) for the br-mediated trait and to provide resources for cloning this gene, we fine-mapped br to the tomato genome. Fine mapping of br to chromosome 1 was initiated by a survey of genome-wide single-nucleotide polymorphisms (SNPs) shown to be polymorphic between the br phenotype and normal using the tomato array, identifying the interval that harbors br. Genetic markers that flank the locus further permitted saturation of the interval. Twenty-six fixed homozygous recombinant lines were identified together in two different populations and tested with those markers. These efforts resulted in the first report that the br is fine-mapped to a 763-kb physical interval of tomato reference genome. The identified markers close to the br in the present study will be significant resources for MAS and gene cloning research.

Yield and fruit quality of grafted tomatoes, and their potential for soil fumigant use reduction. A meta-analysis

Grafted fresh market tomatoes are widely used in commercial production throughout Europe and Asia, and interest among commercial producers in the Americas has increased in recent years. Many field trials have found dramatic net economic return increases relative to non-grafted scion cultivars. However, optimal yields require growing conditions that satisfy the agronomic needs of both rootstock and scion cultivars. Most commercial rootstocks are resistant to multiple soilborne pathogens, allowing grafted plants to maintain high yields in pathogen-infested fields without the use of soil pesticides, including fumigants. Here we comprehensively and quantitatively review, for the first time, all available published trial data on fruit quality and yield of grafted tomatoes. Collectively, 159 publications included 202 different rootstocks, 126 geographic locations, and 1023 experimental treatments. Yield performance varies with the specific rootstock/scion combinations and with the conditions of a given production system. Among 949 heterograft treatments (rootstock/scion of different cultivars), grafted plant yields were not significantly higher in 65% of the cases, yet they averaged a 37% yield increase for all data. In addition, grafted/non-grafted yield ratios in 105 experimental treatments with rootstock ‘Maxifort’ varied dramatically by scion. However, European trials used completely different scions than US trials, so the roles of scion and geographical differences remain unclear. Concerns that grafting might contribute to inferior fruit quality (pH, titratable acidity, total soluble solids, lycopene, vitamin C, firmness, “taste”) seem unfounded in general, though isolated cases show dramatic differences. Grafted tomatoes show promise to reduce the usage of various soilborne pathogen treatments, with 33% of commercial tomato rootstocks either resistant or highly resistant to seven or more common soilborne pathogens. Our approach integrated trial data from around the world, though limitations in available data complicated our analysis of relationships between some experimental variables and fruit yields and quality.

The U.S. Tomato Industry: An Overview of Production and Trade

Tomatoes are one of the world's most consumed vegetable crops. In the United States, domestic production meets about 40% of the total domestic demand for fresh-market tomatoes, with the rest of the demand met by imports, mostly from Mexico and Canada. Since 2000, however, fresh tomato production in the United States has exhibited a steady declining trend. One major reason is the increased competition from Mexico. This 4-page fact sheet written by Zhengfei guan, Trina Biswas, and Feng Wu and published by the UF/IFAS Food and Resource Economics Department argues for US government measures to help the domestic tomato industry resolve labor shortages and encourage research and development of labor-saving technologies such as mechanical harvesting to make the US tomato industry more competitive and sustainable. http://edis.ifas.ufl.edu/fe1027

Labor Requirement and Costs for Harvesting Tomatoes

Florida accounts for 30% to 40% of all commercially produced fresh-market tomatoes in the United States. Almost every southern county in the state grows tomatoes. This 4-page fact sheet written by Zhengfei Guan, Feng Wu, and Steven Sargent and published by the UF/IFAS Food and Resource Economics Department presents the results of a 2015 study that examined the time it takes to harvest this important crop. http://edis.ifas.ufl.edu/fe1026

HARVESTING FRUITS USING A MOBILE PLATFORM: A CASE STUDY APPLIED TO CITRUS

Harvesting fruits and vegetables for the fresh market and processing industry has been a challenge. Mobile platforms for harvesting vegetables and fruits have been used, but some limitations have been pointed out, such as their applicability for a certain time of the year and for a specific crop. A mobile platform was initially developed for harvesting fresh market tomatoes, mainly staked in Brazil. However, after field trials, many problems were identified, such as crop use limitation and machine structure problems. Therefore, the initial project was reformulated through wheels that move independently, to allow the equipment to spin on its own axis and assume different functions, with a retractable and smaller frame than the previous version and the possibility of adding on other devices, expanding crop harvest and farm use. The concept of a hybrid vehicle with one electric power generator to drive all four wheels with electric motors was kept. The main goal of this article is to describe the development of the mobile platform machine showing previous studies to approach the final concept, structural details and integration of the electrical, hydraulic, and mechanical project and field tests performed in a commercial orange orchard, comparing harvest types, evaluating yield and machine performance. Tests with the mobile laboratory prototype show its potential application to assisted harvest and to other farm operations, especially due to its mobility. Harvest productivity through machine was higher, though not significantly different from manual harvest.

Impact of bacterial spot outbreaks on the phytosanitary quality of tomato and pepper seeds

The impact of disease outbreaks on the phytosanitary quality of seeds was investigated for two pathosystems: tomato–Xanthomonas vesicatoria and pepper–Xanthomonas euvesicatoria. This study, which was performed in Italy and Serbia, aimed to evaluate the season‐to‐season transmission of phytopathogenic regulated bacteria associated with phytosanitary risks posed by seeds produced in areas where bacterial infections are possible. For each pathosystem, field plots were experimentally inoculated to simulate an initial infection rate of 1%, 5% and 15%. The area under the disease progress curve (AUDPC) was calculated for each field plot, the seeds produced were analysed to determine the contamination level and rate, and the plant‐to‐seed transmission was evaluated by a seedling grow‐out (SGO) assay. To investigate transmission under field conditions, a second‐year experiment was performed, wherein seeds collected from the first year were used to establish new field plots. During the first growing season, AUDPC values were positively correlated with the percentages of initial infection for each pathosystem. Seed contamination levels in pepper ranged from 34 to 100 CFU g−1, and the contamination rate ranged from 1.50% up to 3.17% for X. euvesicatoria, whereas processing and fresh market tomato seeds produced both in Italy and Serbia were not infected by X. vesicatoria. During SGO assays and the second cropping year, no symptoms were observed in either tomato or pepper plants. Therefore, the calculated pepper seed contamination rate for X. euvesicatoria appeared to be less than the threshold necessary to initiate a disease outbreak. Finally, all seeds obtained during the second cropping year were uninfected.

EFFECTS OF SCHEDULING TECHNIQUES OF WATER APPLICATION FOR DRIP IRRIGATION SYSTEM ON TOMATO YIELD IN ARID REGIO

Irrigation is necessary in order to produce tomato in arid regions such as Saudi Arabia, with limited water supplies. Drip irrigation (DI) is being adopted in these areas to conserve water under economical crop production. Field experiment was carried out to study effects of different irrigation scheduling management strategies on fruit yield, quality of drip-irrigated fresh market tomatoes, water use efficiency and irrigation application efficiency. The experiment included three scheduling methods, which were used to irrigate tomato field: Evapotranspiration (ET) controller, soil moisture sensor (watermark sensor) and control treatment based on weather data. All irrigation-scheduling methods were effective, prescribing different amount of water for a given season. Irrigation amount increased from 841.5 mm (ET controller) to 882.60 mm (watermark sensor) and 1034.33 mm (control treatment), during two seasons. Both WUE and IWUE increased with decrease in irrigation water depth. The maximum average WUE (7.26 kg-m–3) and IWUE (4.66 kg-m– 3) values were for ET controller as average, during the two seasons. In addition, ET controller method conserved up to 7 % and 18% water compared to the watermark sensor and control treatments, respectively. Based on the above results, it is recommended that if the tomatoes are well irrigated based on ET controller, the farmer can get higher tomato yield in areas experiencing severe drought, such as Saudi Arabia.

A methodology for fresh tomato maturity detection using computer vision

Recent advancements in computer vision have provided opportunities for new applications in agriculture. Accurate yield estimation of fruit and vegetable crops is very important for better harvesting and marketing planning and logistics. This paper proposes a method for detecting the maturity levels (green, orange, and red) of fresh market tomatoes (Roma and Pear varieties) by combining the feature color value with the backpropagation neural network (BPNN) classification technique. A maturity detection device based on computer vision technology was designed specifically to acquire the tomato images in the lab. The tomato images were processed and the targets of the tomatoes were obtained based on the image processing technology. After that, the maximum inscribed circle of the tomato’s surface was identified as the color feature extraction area. The color feature extraction area was divided into five concentric circles (sub-domains). The average hue values of each sub-region were extracted as the feature color values and used to describe the maturity level of the samples. After that, the five feature color values were imported to the BPNN as input values to detect the maturity of the tomato samples. Analysis of the results shows that the average accuracy for detecting the three maturity levels of tomato samples using this method is 99.31%; and the standard deviation is 1.2%.

Molecular Markers to Select for the j-2–mediated Jointless Pedicel in Tomato

The jointless pedicel trait of tomato conferred by the j-2 gene is widely used in processing markets for stem-free removal of fruit to accommodate mechanized harvest. Although current utilization of j-2 for fresh-market tomato breeding is limited, interest in this trait may increase as breeders seek to address high labor costs through the development of mechanically harvestable cultivars for the fresh market. Yet, the introduction of this trait into new market classes heavily relies on phenotypic selection because there are presently no high-throughput methods available to genotype j-2. Reliable, high-throughput molecular markers to genotype the presence/absence of j-2 for selective breeding were developed. The molecular markers described here use the high-resolution DNA melting analysis (HRM) genotyping with single-nucleotide polymorphism (SNP) and derived cleaved amplified polymorphic sequence (dCAPS)–based genotyping. Two separate HRM-based markers target the j-2 on chromosome 12 or a linked sequence region 3.5 Mbp apart from the gene, and a dCAPS marker resides on the latter. We demonstrate the association between each marker and the jointless pedicel phenotype using segregating populations of diverse filial generations in multiple genetic backgrounds. These markers provide a useful resource for marker-assisted selection of j-2 in breeding populations.

First Report of Tomato Necrotic Spot Virus Infecting Tomato in Indiana

During the 2017 growing season, high-tunnel-grown fresh market tomatoes from an Indiana producer were identified with virus-like symptoms. Foliar symptoms included necrotic spotting and flecking, and stems had necrotic streaks. Fruit had an extensive pattern of necrotic concentric lines, spots, and scabbing, making them unsaleable. Around 5% of the plants exhibited symptoms. Degenerate Ilarvirus group-specific primers identified the virus as belonging to the Ilarvirus group. Primers designed to amplify the coat protein identified the virus as tomato necrotic spot virus, previously only reported in processing tomatoes in California.

A Review of Corynespora cassiicola and Its Increasing Relevance to Tomato in Florida

Corynespora cassiicola is a highly diverse fungal pathogen that can infect more than 500 species of plants, including many economically important crops such as cotton, soybean, tomato, and cucumber. In Florida, the number one vegetable crop by market value are fresh-market tomatoes, which generate nearly half a billion dollars annually. Florida’s subtropical to tropical climate is conducive to infection and development of the target spot pathogen on tomato caused by C. cassiicola. There is no varietal resistance available for target spot of tomato, and preventative fungicide treatments are the primary method for control. In the last decade, C. cassiicola has been more frequently reported by Florida tomato growers, appearing not only more aggressive but also increasingly insensitive to various fungicides. This review brings together the most recent C. cassiicola literature, providing a history and understanding of the immense pathogen diversity and its relevance to tomato. It also provides insight into fungicide resistance development and pathogen survivability, which are important factors in providing effective control recommendations and in understanding the epidemiology of this disease, respectively.

Distribution and Characterization of Xanthomonas Strains Causing Bacterial Spot of Tomato in Indiana

Over a 2-year period, samples of tomato suspected of being infected with bacterial spot were collected across Indiana and sent to the Purdue Plant and Pest Diagnostic Laboratory (PPDL). A total of 50 strains were collected over 2 years. An effort was made to collect from both fresh market and processing tomato fields (22 from fresh market, 25 from processing, and 3 unspecified). The PPDL screened samples for bacterial spot, and they isolated and confirmed the pathogen. The Xanthomonas isolates were then sent to Jeff Jones at the University of Florida to determine taxonomic identification, race determination, and sensitivity to copper at 50 ppm and streptomycin at 200 ppm. The majority of Xanthomonas strains collected (78%) were classified as X. perforans. The majority of the X. perforans strains were designated race T4. A total of 12% of strains were classified as X. gardneri, all of which were collected north of U.S. I-70, a route that bisects the state into approximately even halves. X. euvesicatoria was only observed on one sample. X. vesicatoria was not observed. Of all strains collected in Indiana, 84% were copper tolerant. In contrast, only 58% of the strains were insensitive to streptomycin.

Genetic Analysis for Fruit Yield and Quality Attributes in Some Processing and Fresh Market Tomato Genotypes

ABSTRACTHigher demands for improved fruit yield and processing qualities for Tomato (Solanum lycopersicum L.) could be met through heterosis breeding. It is important to identify the parental line combination performing better for economically important quality traits. The experiment was composed of seven tomato inbred lines (two processing and five fresh market) and 21 F1 hybrids produced by crossing of them in a 7 × 7 half-diallel fashion. The nature and type of gene actions were analyzed to determine how they were involved in inheritance of fruit per plant, yield per plant, average fruit weight, total soluble solids, fruit juice pH, titratable acidity, sugar acid ratio, fruit juice content, shape index, and pericarp thickness. Most characters were predominantly controlled by nonadditive gene actions. Employing hybrid breeding for improving characters could be effective. The crosses ‘Metadel × Marglobe’, ‘Bishola × CLN2037E’, ‘Roma VF × ARP Tomato d2’, ‘Roma VF × CLN2037E’, ‘ARP Tomato d2 × Marglobe’, and ‘Eshete × CLN2037E’ showed positive and highly significant specific combining ability (SCA) effects for number of fruit per plant and fruit yield per plant. This indicated that the crosses could be used for developing high-yielding varieties. The crosses ‘Metadel × Roma VF’, ‘Bishola × Roma VF’, ‘Roma VF × Eshete’, and ‘ARP Tomato d2 × Marglobe’ exhibited positive, significant SCA effects for total soluble solids and negative, significant SCA effects for fruit juice pH. These crosses could be utilized as hybrids with better processing qualities. The crosses ‘Metadel × Marglobe’, ‘Bishola × Eshete’, ‘ARP Tomato d2 × CLN2037E’, and ‘Eshete × Marglobe’ exhibited positive, highly significant SCA effects for sugar-to-acid ratio, indicating that they could be used in hybridization for developing lines with better fruit flavor.

Performance of fresh market tomato (Solanum lycopersicum Mill) lines as influenced by pruning

Tomato production in the Philippines is dominated by conventional farmers who do not practice pruning. Currently, rampant occurrence of diseases almost wiped out the industry and availability of resistant seeds became a problem however several studies reported that pruning lessened diseases and enhanced yield. The study aimed to evaluate the effect of pruning on the performance of different fresh market tomato genotypes. The experiment was laid out in factorial design using Randomized Complete Block Design with pruning as Factor A and tomato genotypes as Factor B with Harabas (Harabas Rescuer 746) as control. Pruning obtained thicker stem and 18% higher fruit set, reduced Tomato Yellow Leaf Curl Virus and increased tomato yield by producing a higher number of marketable fruits. AVTO 1173 produced the heaviest and largest fruits with the least TYLCV. Pruning is a beneficial practice that farmers could adopt, along with AVTO 1173 as a substitute for the Harabas, check variety. Additional trials of AVTO 1173 should be conducted in different locations to further verify its adaptability and performance in other situations.

Pseudomonas syringae pv. tomato Strains from New York Exhibit Virulence Attributes Intermediate Between Typical Race 0 and Race 1 Strains.

Bacterial speck disease, caused by Pseudomonas syringae pv. tomato, is a persistent problem for fresh-market tomato growers in New York. Race 0 strains of this pathogen express either or both of the type III effectors AvrPto or AvrPtoB, which are recognized by tomato varieties expressing the Pto resistance gene. Pto encodes a protein kinase that activates the host immune system, thereby inhibiting bacterial multiplication and preventing disease development. Race 1 P. syringae pv. tomato strains do not express these effectors and are virulent on tomato whether or not the variety expresses Pto. Very few fresh-market tomato varieties have the Pto gene. We collected six P. syringae pv. tomato strains from naturally infected tomato plants across New York in 2015 and characterized them for their virulence and for the presence of specific effectors. In experiments conducted in the greenhouse, all strains reached population sizes in Pto-expressing tomato leaves that were intermediate between typical race 0 and race 1 strains. This phenotype has not been observed previously and suggests that the strains are recognized by Pto but such recognition is compromised by another P. syringae pv. tomato factor. The strains were found to encode avrPto, which is transcribed and translated. They also express avrPtoB although, as reported for other P. syringae pv. tomato strains, protein expression for this effector was not detectable. Deletion of avrPto from a representative New York strain allowed it to reach high populations in Pto-expressing tomato varieties, without compromising its virulence on susceptible tomato plants. Collectively, our data suggest that introgression of the Pto gene into fresh-market tomato varieties could enhance protection against extant P. syringae pv. tomato strains.

Hairy vetch becomes an alternative basal N fertilizer in low-input fresh-market tomato production in plastic high tunnel

Environment pollution is one of the major concerns in recent times. In order to establish low-input alternative production systems based on cover crops, the effectiveness of hairy vetch (Vicia villosa Roth; HV) incorporated as a basal nitrogen (N) fertilizer in fresh-market tomato production in plastic high tunnel was investigated in Sapporo, Japan. The treatments consisted of HV seeding rates (HV20, 20 kg ha-1; HV50, 50 kg ha-1) and ammonium sulfate (AS100, 100 kg ha-1) applied as basal N fertilizers, and the control with no basal fertilizer. In all plots, 150 kg ha-1 of N was added as topdressing slow-release N fertilizer (LPS100 41%-N) before transplanting. HV aboveground biomass (dry weight) was 5.85 t ha-1 in HV20 and 7.19 t ha-1 in HV50. Nitrate in petiole sap was found to be higher in HV20, HV50 and AS100 plots than in control plots throughout the cultivation period with the exception of the first 2 weeks after transplanting (WAT). The growth index (GI) was higher in HV20 (47971), HV50 (46285), and AS100 (43397) than in control (39847) at 7 WAT. Higher marketable yields were found in tomatoes grown in HV20 (68.7 t ha-1), HV50 (69.1 t ha-1) and AS100 (60.8 t ha-1), compared with control (51.9 t ha-1). The HV plots had greater soil organic nitrogen and soil carbon than AS100 and control after tomato production. From these results, the HV seeding rate of 20 kg ha-1 will be enough to support the growth of tomato planted after HV production if HV grows smoothly in greenhouse.