Potted Tomato Research Articles

Dual-arm cooperation and implementing for robotic harvesting tomato using binocular vision

Dual-arm cooperation is considered as an available approach to improve the poor efficiency by autonomous robotic harvesting. While, cooperating arm movements using visual information is a key challenge for harvesting robots working in non-structured environments. In this paper, we develop a dual-arm cooperative approach for a tomato harvesting robot using a binocular vision sensor. Firstly, a tomato detection algorithm combining AdaBoost classifier and color analysis is proposed and employed by the harvesting robot. Then, a fast three-dimensional scene reconstruction method is obtained in the simulation environment by using point clouds acquired from a stereo camera. Integration of tomato detection, target localization, motion planning and real-time control for dual-arm movements, the dual-arm cooperation for robotic harvesting can be implemented. To validate the proposed approach, field experiments were conducted with the potted tomatoes in greenhouse. Over 96% of target tomatoes were correctly detected with the speed of about 10 fps. The positioning error of robot end-point of less than 10 mm was achieved for large scale direct positioning of the harvesting robot. With the vacuum cup grasping and wide-range cutting, the success rate of robotic harvesting achieved 87.5%. Meanwhile, the harvesting cycle time excluding cruise time was less than 30 s. These results indicate that the dual-arm cooperative approach is feasible and practical for robotic harvesting in non-structured environments.

Response of Potted Tomato on CRH-Treated Oxisols

Response of Potted Tomato on CRH-Treated Oxisols

Efficiency of garden waste compost teas on tomato growth and its suppressiveness against soilborne pathogens

ABSTRACT: The use of compost teas is of great interest to sustainable agriculture. Aerated compost tea (ACT) and aerated vermicompost tea (AVT) originating from garden waste have been analytically characterized and tested in vitro and in vivo on tomato plants to determine their suppressive effect on Rhizoctonia solani and Fusarium oxysporum f. sp. lycopersici. The nitrogen (N, 3840 ppm) and potassium superoxide (K2O, 5800 ppm) contents were relevant in ACT. Both ACT and AVT were shown to contain indoleacetic acid IAA (80 - 20 mg L−1), salicylic acid (5.85 - 1.33 ng L−1) and humic acids (190 - 140 mg L−1). Direct confrontation assays against the pathogens showed that ACT had a high suppressive effect on F. oxysporum f. sp. lycopersici (relative growth of the pathogen [RG]: 12 %) and AVT had a high suppressive effect on R. solani (RG: 18 %). These suppressive effects have been confirmed by tests performed in vitro and on potted tomato plants. Results of plants growth assays showed that both teas can be applied, in their concentrated forms, to the growth medium. The analysis of the growth effect of the teas on tomato plants clearly indicated that both ACT and AVT, when applied weekly, produce a positive effect on shoot and root dry weight (dry weights were tripled), chlorophyll content and stem diameter compared to untreated plants. These results support the use of ACT and AVT as potential alternatives to the application of synthetic fungicides, and as plant promoters in crop production, for attaining environmental sustainability for farming and food safety.

Nematicidal potential of Taraxacum officinale.

This study was aimed to investigate the activity of the Asteraceae species Taraxacum officinale against the root-knot nematode Meloidogyne incognita. Leaf and root extracts of T. officinale were tested in vitro at a range of 62.5-1000 and 250-1000μgmL-1 concentrations on nematode juveniles and eggs, respectively, whereas treatments with 10-40gkg-1 soil rates of dry leaf and root T. officinale biomass were applied to soil infested by M. incognita in greenhouse experiments on potted tomato. Peak 36 and 50% juvenile mortality and 14.8 and 23.8% egg hatchability reduction were recorded at the maximum concentration of leaf and root extracts, respectively. Soil treatments with T. officinale leaf and root material strongly suppressed nematode multiplication and gall formation on tomato roots and significantly increased plant growth. Chicoric acid and 3-O- and 3,5-di-O-caffeoylquinic acid were found to be the main components of leaf and root extract, respectively, and proved, as the total hydroalcoholic extracts from T. officinale leaf and root material, for an antioxidant activity. Data from this study indicate the suitability of plant materials from T. officinale for a potential formulation of nematicidal products to include in sustainable nematode management strategies.

Osmotic adjustment and up-regulation expression of stress-responsive genes in tomato induced by soil salinity resulted from nitrate fertilization

Concerns about the soil salinity caused by excessive fertilization have prompted scientists to clarify the detailed mechanisms and find techniques to alleviate the damage caused by this kind of soil salinity. Aims of this study were to elucidate the effect of soil salinity caused by nitrate fertilization and the differences in salinity effect between nitrate salts and NaCl salt with analyses at various levels of crop physiology and molecular biology. A microbial inoculation was also tried to verify whether it could alleviate the salinity-induced loss and damages. In three experiments (Exp I, II and III), nitrate salts (NS) of Ca(NO3)2 and KNO3 were applied to potted tomato plants to simulate the soil salinity caused by fertilization and a microbial inoculant (MI) was applied. Photosynthesis was measured using Li-6400. Osmotic adjustment was analyzed using the mathematically modeled pressure-volume curve; O2- concentration and activity of SOD and nitrate reductase were measured. Expression of nitrate reductase gene and the stress-responsive gene DREB2 was analyzed using the real-time PCR method. In Exp I and II, where the applied NS amount was moderate, NS application at low concentration induced increases in O2- and MDA concentrations and plants acclimated to the soil salinity as the treatment prolonged for weeks. The acclimation was contributed by osmotic adjustment, activation of SOD and re-compartmentation of cell water between symplasm and apoplasm. These adjustments might be ultimately attributed to up-regulation of stress-responsive genes such as DREB2 as well as the nitrate reductase (NR) gene. However, in Exp III, applications of NaCl and NS at high concentration could not show positive effects as NS did. Application of MI synergistically increased the xerophytophysiological regulation caused by NS and alleviated the salinity damage in addition to its own positive effects on the tomato plants. Different from NaCl, nitrate salts at low application rate increased the total biomass and fruit yield of tomato and induced up-regulation expression of stress-responsive genes and the consequent active osmotic adjustment. However, nitrate application at high level negatively affected tomato plants irrespective of the gene up-regulations. Application of MI alleviated the salinity damage and synergistically increased the xerophytophysiological regulation caused by the soil salinity in addition to its positive effects on the tomato crop but the detailed mechanisms needed to be clarified in future further studies. Keywords: nitrate fertilizer, osmotic adjustment, salinity stress, soil salinization, tomato (Solanum lycopersicum); xerophytophysiology, microorganism, bioremediation DOI: 10.25165/j.ijabe.20181103.2952 Citation: Chang T T, Zhang Y J, Xu H L, Shao X H, Xu Q C, Li F L, et al. Osmotic adjustment and up-regulation expression of stress-responsive genes in tomato induced by soil salinity resulted from nitrate fertilization. Int J Agric & Biol Eng, 2018; 11(3): 126–136.

Effect of Formulations and Spray Nozzles on 2,4-D Spray Drift under Field Conditions

Six trials were conducted during 2014/15 and 2015/16 growing seasons in Brazil to determine the effect of 2,4-D formulations and spray nozzles on 2,4-D spray drift under conventional field conditions. An experimental 2,4-D choline formulation with Colex-D® Technology (GF-3073) and a 2,4-D dimethylamine (DMA) formulation were applied with either XR and AIXR flat-fan spray nozzles. Each plot was 30 m wide by 24 m long (720 m2) with 60 glyphosate-resistant soybean rows spaced 50 cm apart and also 35 potted tomato plants distributed on a grid across the plot 5-m apart. Applications were performed one meter away from the plot edge perpendicular to the soybean rows when wind direction was parallel to the rows with less than 30 degrees of angle deviation. Spray drift treatments were applied in 100 L ha−1 with tractor sprayers at 276 kPa equipped with a 7-m wide boom at 50 cm above the canopy of the soybean plant, operating at 6.8 km h−1. The distance from the plot edge to the farthest plant with 2,4-D symptoms was assessed for every four soybean rows at 10 and 20 days after treatment (DAT) and potted tomatoes at 10 DAT. GF-3073 reduced the distance of the farthest injured plant with 2,4-D symptoms compared to the 2,4-D DMA formulation regardless of the spray nozzle, assessment date and sensitive species. GF-3073 applied through the AIXR nozzle reduced the relative drift affected area to the standard by 68% at 10 DAT and 67% at 20 DAT for soybean and 60% at 10 DAT for potted tomatoes.

Simulation of Stomatal Conductance and Water Use Efficiency of Tomato Leaves Exposed to Different Irrigation Regimes and Air CO2 Concentrations by a Modified "Ball-Berry" Model.

Stomatal conductance (gs) and water use efficiency (WUE) of tomato leaves exposed to different irrigation regimes and at ambient CO2 (a[CO2], 400 ppm) and elevated CO2 (e[CO2], 800 ppm) environments were simulated using the “Ball-Berry” model (BB-model). Data obtained from a preliminary experiment (Exp. I) was used for model parameterization, where measurements of leaf gas exchange of potted tomatoes were done during progressive soil drying for 5 days. The measured photosynthetic rate (Pn) was used as an input for the model. Considering the effect of soil water deficits on gs, an equation modifying the slope (m) based on the mean soil water potential (Ψs) in the whole root zone was introduced. Compared to the original BB-model, the modified model showed greater predictability for both gs and WUE of tomato leaves at each [CO2] growth environment. The models were further validated with data obtained from an independent experiment (Exp. II) where plants were subjected to three irrigation regimes: full irrigation (FI), deficit irrigation (DI), and alternative partial root-zone irrigation (PRI) for 40 days at both a[CO2] and e[CO2] environment. The simulation results indicated that gs was independently acclimated to e[CO2] from Pn. The modified BB-model performed better in estimating gs and WUE, especially for PRI strategy at both [CO2] environments. A greater WUE could be seen in plants grown under e[CO2] associated with PRI regime. Conclusively, the modified BB-model was capable of predicting gs and WUE of tomato leaves in various irrigation regimes at both a[CO2] and e[CO2] environments. This study could provide valuable information for better predicting plant WUE adapted to the future water-limited and CO2 enriched environment.

Design and experiment of automatic transplanting device for potted tomato seedlings

In this study, an automatic machine for transplanting potted tomato seedlings was designed, based on the analysis of physical characteristics of the main varieties of tomato seedlings. The machine is composed of a horizontal and vertical seedling supply mechanism, a picking mechanism composed with a gear-rod component, a planting part featured with an eccentric-disk parallelogram duckbilled mechanism, and a control system. The control system included position sensors, stepper motor, variable-frequency motor and program controller. The force condition for successful picking potted tomato seedlings was studied by analyzing the force and motion during the taking procedure with the use of analytical graphic method. Combined with the parameters of physical characteristics of tomato seedlings, the key parameters of the machine was determined, which included L1 = 105 mm as the distance between the point of the gripper needles and the center of rotation, L0 = 18 mm as the initial opening distance between the two gripper needles, and s = 40 mm as the distance between the two gripper needles when they were at the upper hinge point of the clamping hands. The key structure and the parameters of the seedlings-taking part were determined by theoretical calculation according to the position of the seedling during taking and dropping procedure, and the requirement of the motion. The machine was tested by using the potted tomato seedlings. The result showed that the seedling picking rate was 92.35%–86.61%, and the leakage rate was 12.57%–18.03%, when the transplanting speed was between 60 and 90 seedlings per minute. The result demonstrated that the machine was feasible to transplant the potted tomato seedlings efficiently.

Analysis of the heterogeneity of Ralstonia solanacearum avirulent espD-mutant by high performance ion-exchange chromatography

The heterogeneity of Ralstonia solanacearum avirulent espD-mutant, virulent wildtype strain FJAT-91 and spontaneous avirulent strain FJAT-1458 were compared and analyzed by using high performance ion-exchange chromatography (HPIEC). Their colony and cell morphologies were observed, and the contents of their extracellular polysaccharides (EPS) were determined. The results showed that the colony and cell morphologies of FJAT-91 ⊿epsD were different from the original strain FJAT-91, but were similar to the spontaneous avirulent strain FJAT-1458. The EPS content of FJAT-91 ⊿epsD was (12.64±1.46) μg/mL, which was much lower than FJAT-91 with (30.49±2.97) μg/mL. The strain FJAT-91 were separated into single peak of P3 at the retention time of 6.04 min, and FJAT-91 ⊿epsD had two peaks (P1 and P2) at the retention times of 0.59 min and 4.62 min, respectively. FJAT-1458 formed single peak of P1 at the retention time of 0.59 min. Then, the bacteria eluents from different chromatographic peaks were collected and their pathogenicities were detected with bioassay test using potted tomatoes in the greenhouse. The results showed that the tomato plants began to wilt 4 d after inoculation of strain FJAT-91-P3 eluted from P3, and the disease incidence reached 100% at 10 d post inoculation. The strain FJAT-91 ⊿epsD-P2 eluted from P2 caused tomato plants wilting 9 d after inoculation, and the disease incidence reached 100% at 20 d. During 20 d of observation, none of tomato plants caused wilting while inoculation with FJAT-1458-P1 and FJAT-91 ⊿epsD-P1 eluted from P1 of FJAT-1458 and FJAT-91 ⊿epsD, respectively. In this paper, the morphologies, EPS contents and chromatographic behaviors of FJAT-91, FJAT-91 ⊿epsD and FJAT-1458 were compared, which would provide theoretical basis for using FJAT-91 ⊿epsD to control bacterial wilt disease.

Preliminary results of a pot experiment with the combined effects of a terrestrial isopod species (Porcellionides pruinosus, Brandt 1833) and organic mulching on tomato

Organic mulching practice has a beneficial effect on soil life. Increased soil activity may in turn lead to increased soil fertility. To study the effect of terrestrial isopods and organic mulch on potted tomatoes we measured the growth, vitality and yield of plants. Half of the pots had the surface of the soil covered with a mulch of equal quantity of walnut (Juglans regia), elm (Ulmus minor) and maple (Acer platanoides) leaves; and half of them had the soil uncovered. 20 Porcellionides pruinosus (Brandt, 1833) individuals were introduced to every second pot. There were four treatments in 10 replicates: (1) I+M+ (isopods, mulching); (2) I+M- (isopods, no mulching); (3) I-M+ (no isopods, mulching) and (4) I-M- (no isopods, no mulching). To determine the microbial activity of the soil, fluorescein diacetate hydrolysis activity was measured. The fluorescein diacetate concentration was higher in the “combined” treatment than in the “isopods only” treatment, and in the “mulch only” treatment. Regardless of treatment, overall microbial activity figures were lower after the experiment than their respective starting values. The “combined” treatment significantly increased the generative growth of tomatoes. The number of flowers was significantly higher, and thus significantly more tomato was harvested when compared to the “control” treatment. Our preliminary results indicate the beneficial effects of P. pruinosus, because its presence had an advantageous influence on tomato yield.

Osmotic adjustment and up-regulation expression of stress-responsive genes in tomato induced by soil salinity resulted from nitrate fertilization

Concerns about the soil salinity caused by excessive fertilization have prompted scientists to clarify the detailed mechanisms and find techniques to alleviate the damage caused by this kind of soil salinity. Aims of this study were to elucidate the effect of soil salinity caused by nitrate fertilization and the differences in salinity effect between nitrate salts and NaCl salt with analyses at various levels of crop physiology and molecular biology. A microbial inoculation was also tried to verify whether it could alleviate the salinity-induced loss and damages. In three experiments (Exp I, II and III), nitrate salts (NS) of Ca(NO3)2 and KNO3 were applied to potted tomato plants to simulate the soil salinity caused by fertilization and a microbial inoculant (MI) was applied. Photosynthesis was measured using Li-6400. Osmotic adjustment was analyzed using the mathematically modeled pressure-volume curve; O2- concentration and activity of SOD and nitrate reductase were measured. Expression of nitrate reductase gene and the stress-responsive gene DREB2 was analyzed using the real-time PCR method. In Exp I and II, where the applied NS amount was moderate, NS application at low concentration induced increases in O2- and MDA concentrations and plants acclimated to the soil salinity as the treatment prolonged for weeks. The acclimation was contributed by osmotic adjustment, activation of SOD and re-compartmentation of cell water between symplasm and apoplasm. These adjustments might be ultimately attributed to up-regulation of stress-responsive genes such as DREB2 as well as the nitrate reductase (NR) gene. However, in Exp III, applications of NaCl and NS at high concentration could not show positive effects as NS did. Application of MI synergistically increased the xerophytophysiological regulation caused by NS and alleviated the salinity damage in addition to its own positive effects on the tomato plants. Different from NaCl, nitrate salts at low application rate increased the total biomass and fruit yield of tomato and induced up-regulation expression of stress-responsive genes and the consequent active osmotic adjustment. However, nitrate application at high level negatively affected tomato plants irrespective of the gene up-regulations. Application of MI alleviated the salinity damage and synergistically increased the xerophytophysiological regulation caused by the soil salinity in addition to its positive effects on the tomato crop but the detailed mechanisms needed to be clarified in future further studies. Keywords: nitrate fertilizer, osmotic adjustment, salinity stress, soil salinization, tomato (Solanum lycopersicum); xerophytophysiology, microorganism, bioremediation DOI: 10.25165/j.ijabe.20181103.2952 Citation: Chang T T, Zhang Y J, Xu H L, Shao X H, Xu Q C, Li F L, et al. Osmotic adjustment and up-regulation expression of stress-responsive genes in tomato induced by soil salinity resulted from nitrate fertilization. Int J Agric & Biol Eng, 2018; 11(3): 126–136.

Effectiveness of aromatic plant species for repelling and preventing oviposition of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae)

AbstractThis study assesses the effectiveness of essential oils for repelling whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), and deterring oviposition. We evaluated essential oils from four plants: Curcuma longa (Zingiberaceae), Litsea cubeba (Lauraceae), Piper nigrum (Piperaceae) and Zanthoxylum bungeanum (Rutaceae), under laboratory and glasshouse conditions. In the laboratory, ethanol‐extracted essential oils were applied uniformly on both sides of a tomato leaf in the treatment groups, and the same volume of liquid but without essential oil was used for the control. Results showed that essential oils from L. cubeba, P. nigrum, C. longa and Z. bungeanum provided some repellency of whiteflies and reduced oviposition. Oils from L. cubeba repelled adult females (69.14% and 62.49% repellency at 24 and 48 hr, respectively), and oils from C. longa deterred oviposition (68.46% and 65.94% at 24 and 48 hr exposures, respectively). In the glasshouse, potted tomato plants with eight leaves were sprayed with treatments and control material. Five‐day‐old adult female whiteflies were released in a cage between both pots. Essential oils from L. cubeba repelled females 54.77 at 24 hr and P. nigrum 44.37% at 48 hr whereas oils from P. nigrum reduced oviposition by 43.35 at 24 hr and Z. bungeanum 21.08% at 48 hr, under glasshouse conditions. Essential oils show potential to be used to reduce feeding and oviposition, and thus being important components of integrated pest management programs. However, future research is needed to investigate individual compounds of these oils against whitefly, and to enhance their effectiveness.

Artemisia annua compounds have potential to manage root-knot and potato cyst nematodes

Previous in vitro investigation of the nematotoxic effect of Artemisia annua and its main phytochemicals have indicated that this plant can be a potential source of nematicidal products. Following this previous study, the objective of this work was to assess the nematicidal activity of soil treatments with meal and water extract from dry biomass of Artemisia annua on the root-knot nematodes Meloidogyne incognita and M. hapla and on the cyst nematode Globodera rostochiensis in experiments on potted tomato and potato, respectively. Meal was applied at 5, 10, 20 or 40gkg−1 soil rates, whereas soil treatments with 25, 50, 100 and 250gL−1 water solutions of the extract were applied either in a single application or splitted into four treatments. Gall formation and multiplication of both M. incognita and M. hapla on tomato roots were significantly reduced by all soil treatments with A. annua meals. Both single and splitted application of A. annua water extract effectively reduced M. incognita population on tomato roots and in the soil. In the experiment on potato, almost all rates of A. annua meal and extract significantly reduced soil population density of G. rostochiensis, without any statistical difference among the two applications. The nematicidal activity of A. annua products on root-knot nematodes resulted not statistically different or even higher than that of the nematicide fenamiphos. A significant increase of growth was always recorded on tomato and potato plants as a side effect of treatments with meal or water extract. Data from these experiments seem to indicate that products from A. annua can be potential candidates for the formulation of new nematicides suitable for a sustainable nematode management, though field trials are still needed for an effective demonstration of a commercial exploitation.

Post-infection activity of fungicides against Phytophthora infestans on tomato (Solanum lycopersicum L.)

Late blight caused by Phytophthora infestans is the most devastating disease of tomato (Solanum lycopersicum L.) and causes important economically losses if not properly controlled. Control is achieved mainly by preventive fungicide applications. However, even if curative applications are discouraged because they increase the risk of resistance development in the target pathogens, in practice fungicides may be applied also when the disease is already present, a situation that commonly occurs in the field. The aim of this work was to study the curative activity of several fungicides toward P. infestans to determine their efficacy when applied after the infection process. Nine trials were performed in greenhouse using potted tomato plants that were treated 24 h after inoculation. Disease severity was assessed three times from the development of the symptoms on the untreated plants and data analysed using a linear mixed model. Differences in post-infection control between the different chemical classes were found. Metalaxyl-M and cymoxanil showed the best curative activity while among the CAA fungicides, a good efficacy was expressed by dimethomorph. Interestingly, evidence of synergy between active ingredients having different modes of action was observed such as in the mixtures containing dimethomorph + ametoctradin, dimethomorph + pyraclostrobin and fosetyl-Al + propamocarb. This study provided useful information on the post-infection activity of some fungicides used to control tomato late blight and should be taken into account to perform more in depth studies at the field level and to improve the management strategies of the disease.

Evaluation of Agronomic Parameters of Potted Tomato (Lycopersicon esculentum (L) Mill) at Different Rates of Poultry Manure Compost

Evaluation of Agronomic Parameters of Potted Tomato (Lycopersicon esculentum (L) Mill) at Different Rates of Poultry Manure Compost

Effects of Isaria fumosorosea on TYLCV (Tomato Yellow Leaf Curl Virus) Accumulation and Transmitting Capacity of Bemisia tabaci.

Tomato yellow leaf curl virus (TYLCV) is transmitted by the Bemisia tabaci pest Middle East-Asia Minor 1 (MEAM1) in China. Isaria fumosorosea is a fungal pathogen of B. tabaci. However, the effects of fungal infection on TYLCV expression and transmission by MEAM1 are unclear. In this study, potted tomatoes containing second instar nymphs of MEAM1 were treated with I. fumosorosea IfB01 strain and the relationship between fungal infection in MEAM1 and its TYLCV transmission capacity was investigated. The results indicated that a significantly (p < 0.05) decreased incidence of transmission of TYLCV-infected plants (ITYPs) transmitted by second instar nymphs of MEAM1 infected with fungus. Further, we found a negative correlation between fungal conidial concentrations and eclosion rates of MEAM1, and a positive correlation between ITYPs and eclosion. In addition, when each plant was exposed to three adults treated with fungus, a significantly decreased transmission of TYLCV (TYTE) was observed in the infected group. However, the incidence of TYLCV-carrying MEAM1 adults (ITYAs) was not significantly different in the infected and control groups (p < 0.05). Nevertheless, a significant decrease in viral accumulation using TYLCV AC2 gene as a marker was observed in the fungus-infected MEAM1. In conclusion, the results suggested that I. fumosorosea infection decreases TYLCV accumulation in MEAM1 and subsequently reduces its transmission. Our study provides new insights into the relationship between host plant, plant virus, insect vector, and entomopathogenic fungus.

Impact of post-infiltration soil aeration at different growth stages of sub-surface trickle-irrigated tomato plants

Abstract Sensitivity to low rhizosphere soil aeration may change over time and therefore plant response may also depend on different growth stages of a crop. This study quantified effects of soil aeration during 5 different periods, on growth and yield of trickle-irrigated potted single tomato plants. Irrigation levels were 0.6 to 0.7 (low level) or 0.7 to 0.8 (high level) of total water holding capacity of the pots. Soil was aerated by injecting 2.5 l of air into each pot through the drip tubing immediately after irrigation. Fresh fruit yield, above ground plant dry weight, plant height, and leaf area index response to these treatments were measured. For all these 4 response variables, means of post-infiltration aeration between 58 to 85 days after sowing were 13.4, 43.5, 13.7, and 37.7% higher than those for the non-aerated pots, respectively. The results indicated that: post-infiltration soil aeration can positively impact the yield and growth of sub-surface trickle-irrigated potted tomato plants; positive effects on plant growth can be obtained with aeration during the whole growth period or with aeration for partial periods; positive growth effects of partial periods of aeration appears to persist and result in yield benefit.

Usage of green manure plants as cover-crops in controlling root-knot nematode, Meloidogyne incognita (Kofoid and White) on tomato, Lyco-persicon esculentum (Mill.)

This study was conducted to determine the nematicidal effect of aqueous extractions of dry plant materials, Tithonia diversifolia, Gliricidia sepium and Tagetes erecta on juveniles of Meloidogyne incognita (Kofoid and White) and to determine the effect of dry leaves of wild sunflower, dry leaves of Gliri-cidia, and dry plant parts of marigold as cover crops on the growth of potted tomato, Lycopersicon esculentum (Mill.) infested with M. incognita. Nemati-cidal effect of aqueous extracts of T. diversifolia, G. sepium and T. erecta (20 g/ 100 mL w/v) were evaluated at 0.05 g/mL, 0.1 g/mL and 0.2 g/mL concentrations in the laboratory bioassay. Results revealed that 0.1 g/ mL and 0.2 g/ mL concentration of T. erecta and 0.2 g/mL concentration of T. diversifolia were very effective in juvenile mortality by over 50% within 48 hours com-pared to other treatments. T. erecta plant parts were the most effective causing above 70% juvenile mortality in 48 hours. M. incognita infested potted tomato plants supplement with dry plant parts of Marigold (2% w/w) showed; significantly higher number of green leaves (P=0.000, F=10.95); significantly lower number of yellow leaves (P=0.001, F=6.78); significantly high-er plant height (P=0.000, F=8.90), stem diameter (P=0.000, F=11.83), root length (P=0.000, F=14.71) and root weight (P=0.000, F=15.08); significantly lower number of root galls (P=0.000, F=116.74), gall index (P=0.000, F=95.80) and significantly lower population of M. incognita in soil (P=0.000, F=24.78) compared to other treatments. This study concludes that addition of botani-cals as cover crops enhanced plant growth and significantly reduced root-knot infestation in tomato plants.

Nutrient salt balance differences on the growth of potted banana, orange or tomato plants growing in sand or sand/CaCO3and fertigated with highly saline solutions

Nutrient salt balance differences on the growth of potted banana, orange or tomato plants growing in sand or sand/CaCO₃and fertigated with highly saline solutions

Effect of Post-Infiltration Soil Aeration at Different Growth Stages on Growth and Fruit Quality of Drip-Irrigated Potted Tomato Plants (Solanum lycopersicum).

Soil hydraulic principles suggest that post-infiltration hypoxic conditions would be induced in the plant root-zone for drip-irrigated tomato production in small pots filled with natural soil. No previous study specifically examined the response of tomato plants (Solanum lycopersicum) at different growth stages to low soil aeration under these conditions. A 2 × 6 factorial experiment was conducted to quantify effects of no post-infiltration soil aeration versus aeration during 5 different periods (namely 27–33, 34–57, 58–85, 86–99, and 27–99 days after sowing), on growth and fruit quality of potted single tomato plants that were sub-surface trickle-irrigated every 2 days at 2 levels. Soil was aerated by injecting 2.5 liters of air into each pot through the drip tubing immediately after irrigation. Results showed that post-infiltration aeration, especially during the fruit setting (34–57 DAS) and enlargement (58–85 DAS) growth stages, can positively influence the yield, root dry weight and activity, and the nutritional (soluble solids and vitamin C content), taste (titratable acidity), and market quality (shape and firmness) of the tomato fruits. Interactions between irrigation level and post-infiltration aeration on some of these fruit quality parameters indicated a need for further study on the dynamic interplay of air and water in the root zone of the plants under the conditions of this experiment.