Greenhouse and Processing Crops Research Center

Stoke-on-Trent, United Kingdom

Greenhouse and Processing Crops Research Center

Stoke-on-Trent, United Kingdom

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Adam Arsovski A.,Agriculture and Agri Food Canada | Yu K.,Greenhouse and Processing Crops Research Center
Molecular Plant Pathology | Year: 2016

Rsv1, a single dominant resistance locus in soybean, confers extreme resistance to the majority of Soybean mosaic virus (SMV) strains, but is susceptible to the G7 strain. In Rsv1-genotype soybean, G7 infection provokes a lethal systemic hypersensitive response (LSHR), a delayed host defence response. The Rsv1-mediated LSHR signalling pathway remains largely unknown. In this study, we employed a genome-wide investigation to gain an insight into the molecular interplay between SMV G7 and Rsv1-genotype soybean. Small RNA (sRNA), degradome and transcriptome sequencing analyses were used to identify differentially expressed genes (DEGs) and microRNAs (DEMs) in response to G7 infection. A number of DEGs, DEMs and microRNA targets, and the interaction network of DEMs and their target mRNAs responsive to G7 infection, were identified. Knock-down of one of the identified DEGs, the eukaryotic translation initiation factor 5A (eIF5A), diminished the LSHR and enhanced viral accumulation, suggesting the essential role of eIF5A in the G7-induced, Rsv1-mediated LSHR signalling pathway. This work provides an in-depth genome-wide analysis of high-throughput sequencing data, and identifies multiple genes and microRNA signatures that are associated with the Rsv1-mediated LSHR. © 2016 BSPP AND JOHN WILEY & SONS LTD.


Arocha-Rosete Y.,Sporometrics | Arocha-Rosete Y.,University of Windsor | Zunnoon-Khan S.,Greenhouse and Processing Crops Research Center | Krukovets I.,Greenhouse and Processing Crops Research Center | And 6 more authors.
Canadian Journal of Plant Pathology | Year: 2011

Peach trees exhibiting peach rosette-like disease symptoms and infected by a phytoplasma of group 16SrI 'Candidatus Phytoplasma asteris' at the Canadian Clonal Genebank were further tested for the pathogen characterization based on the 16S rRNA gene. Nested PCR with phytoplasma universal primers R16mF2/R1 and R16F2n/R2 resulted in amplification of products of approximately 1.25 kb from all four symptomatic trees tested. Virtual RFLP of the R16F2n/R2 sequenced amplicons with selected restriction endonucleases showed unique RFLP patterns when compared to the described 16SrI phytoplasma subgroups; these data were confirmed by phylogenetic analyses. The phytoplasma was therefore assigned as a member of a new 16SrI subgroup (16SrI-W). Results represent the first report of a new phytoplasma 16SrI subgroup infecting peach in Canada, and provide a valuable tool for further epidemiological studies on this phytoplasma in peach. © 2011 The Canadian Phytopathological Society.


PubMed | Chinese Academy of Sciences, Huazhong Agricultural University, ShenYang Agricultural University, University of Illinois at Urbana - Champaign and 2 more.
Type: | Journal: Scientific reports | Year: 2015

Soil types have traditionally been determined by soil physical and chemical properties, diagnostic horizons and pedogenic processes based on a given classification system. This is a laborious and time consuming process. Near infrared (NIR) spectroscopy can comprehensively characterize soil properties, and may provide a viable alternative method for soil type recognition. Here, we presented a partial least squares discriminant analysis (PLSDA) method based on the NIR spectra for the accurate recognition of the types of 230 soil samples collected from farmland topsoils (0-10 cm), representing 5 different soil classes (Albic Luvisols, Haplic Luvisols, Chernozems, Eutric Cambisols and Phaeozems) in northeast China. We found that the PLSDA had an internal validation accuracy of 89% and external validation accuracy of 83% on average, while variable selection with the genetic algorithm (GA and GA-PLSDA) improved this to 92% and 93%. Our results indicate that the GA variable selection technique can significantly improve the accuracy rate of soil type recognition using NIR spectroscopy, suggesting that the proposed methodology is a promising alternative for recognizing soil types using NIR spectroscopy.


Cerkauskas R.F.,Agriculture and Agri Food Canada | Ferguson G.,Greenhouse and Processing Crops Research Center | Macnair C.,Agriculture and Agri Food Canada
Canadian Journal of Plant Pathology | Year: 2015

Phytophthora blight (Phytophthora capsici) affecting greenhouse vegetable production in Canada is reported for the first time. Aspects of the epidemiology and management of P. capsici in relation to greenhouse and field vegetable production in Ontario are discussed. Identification of the pathogen was based on cultural, morphological and molecular approaches, the latter using primer set PC1/2. The pathogen caused 10% plant population losses in a greenhouse pepper operation in Leamington, ON in 2006-2007, and 5%, 5% and 10% losses in commercial greenhouse tomato operations at sites in 2007, 2008 and 2011, respectively, with 1000 greenhouse tomato plants affected in 2012. Phytophthora blight occurred in 2006 in Haldimand-Norfolk and Essex counties on field cucumber and pepper, respectively, and in Essex county in 2007 on field pepper, squash and tomato. The disease was not observed on field pepper, tomato or cucumber plants in fungicide efficacy trials near Harrow, ON in 2005-2006 or near St. Williams, ON in 2007 where the disease had occurred previously. Symptom development was most rapid on greenhouse cucumber and least rapid on greenhouse tomato. Virkon® disinfectant at 0.25%, 0.5%, 1% and 2% commercially formulated product was 100% effective in preventing zoospore germination of P. capsici while Chemprocide™ disinfectant was not fully effective at 0.04%, 0.4% and 4%, and Virucidal Extra® was intermediate in efficacy. The fungicides fluazinam, mandipropamid, cyazofamid and fluopicolide were effective in controlling P. capsici on greenhouse tomato, cucumber, and pepper plants for at least a 14-day period. Metalaxyl was less effective, possibly due to partial resistance in the fungus to this chemical. © 2015 © 2015 The contribution of Raymond F. Cerkauskas and Craig MacNair is authored as part of their employment by Agriculture and Agri-Food Canada (AAFC), and Gillian Ferguson as part of her employment by the Ontario Ministry of Agriculture, and copyright is asserted in the contribution by Her Majesty the Queen in Right of Canada.


Kumar K.G.S.,Greenhouse and Processing Crops Research Center | Hao X.,Greenhouse and Processing Crops Research Center | Khosla S.,Ontario Ministry of Agriculture | Guo X.,Greenhouse and Processing Crops Research Center | Bennett N.,Ontario Ministry of Agriculture
Acta Horticulturae | Year: 2016

High-pressure sodium lamps (HPS) are the conventional lighting technology used to increase photosynthetically active radiation in greenhouse crop production. Because of its high operating temperature, HPS can only be used as top lighting placed well above crop canopy, which has resulted in uneven vertical light distribution in tall crops such as high-wire mini-cucumbers. LEDs have low surface temperature and can be used as inter-lighting within canopy to improve vertical light distribution and increase whole light use efficiency. Therefore, a trial was conducted at a commercial greenhouse from October 2014 to January 2015 to evaluate the hybrid lighting systems with top HPS and intra-canopy LED, in comparison to the top HPS only, for year-round high-wire mini-cucumber production. Three lighting treatments consisting of i) Top HPS lighting (177 μmol m-2 s-1) only, ii) Top HPS (177 μmol m-2 s-1) plus one row of LED inter-lighting (49 μmol m-2 s-1), and iii) Top HPS lighting (177 μmol m-2 s-1) plus two rows of LEDs inter-lighting (99 μmol m-2 s-1) were evaluated; each was applied to 550 m2 of growing area. Leaf chlorophyll index of the 10th and 15th leaf was improved by the addition of one row and two rows of interlighting LEDs. The visual fruit quality of mini-cucumbers was also improved with the LED inter-lighting. Fruit yield was increased by 22.3 and 30.8% by the addition of one or two rows of inter-lighting LEDs over no inter-lighting, respectively. Combining the electricity and capital costs, the production cost for each kg of mini-cucumbers would be $ 1.30 for top HPS lighting only, $ 1.45 for top HPS plus one row of inter-lighting LEDs and $ 1.72 for top HPS plus two rows of inter-lighting LEDs, based on the current prices of electricity and LED and HPS light fixtures in Ontario, Canada, the largest greenhouse vegetable production area in North America. The high production cost of hybrid lighting systems is due to the high cost of inter-lighting LED fixtures. It is anticipated that with potential price reduction in LED light fixtures, the production cost with the hybrid lighting system will decrease significantly in the near future.


Cerkauskas R.F.,Agriculture and Agri Food Canada | Ferguson G.,Greenhouse and Processing Crops Research Center
Canadian Journal of Plant Pathology | Year: 2014

Cucumber powdery mildew (Podosphaera xanthii) causes significant annual yield and quality losses in greenhouse production in Canada. Management of the disease was evaluated in various research trials conducted at Harrow, ON from 1999-2007 and at two commercial greenhouse operations in Leamington, ON in 2005-2006. Products evaluated included biological control agents, new classes of fungicides, and materials derived from natural products as well as several traditional fungicides with multi-site modes of action. Best control in the research greenhouse was obtained with applications of Nova, Quintec, strobilurin derivatives (Quadris, Flint, Sovran), Procure, Pristine, JMS Stylet-Oil ®, V-10118, Prev-AM, copper soap, Actigard and sulphur. Disease control was also obtained with Milstop, two fermented milk by-products (Lactosan, Yo-K-San) + surfactant formulations (Agral 90), and Agral 90 only. Applications of K2HPO4 + Agral 90, CaCl2 + Agral 90, and Siliforce were significantly better than the water check while fumed silica was not effective. Among biological control products, Sporodex (Pseudozyma flocculosa) was effective in control of P. xanthii while Serenade (Bacillus subtilis) was not. Actinovate (Streptomyces lydicus) provided control also. Under commercial greenhouse conditions, Milstop, and Lactosan + Agral 90 when applied weekly suppressed powdery mildew development at least equal to that of Nova. Resistance in P. xanthii to high rates of Nova and Pristine was detected in 3 of 17 and 2 of 8 commercial greenhouse cucumber operations, respectively, near Leamington. None of the locations had resistance to both fungicides at commercial rates of application, although one site showed consistently greater resistance of P. xanthii to both fungicides. © 2014 The contribution of Raymond F. Cerkauska.


Hao X.,Agriculture and Agri Food Canada | Wen G.,Agriculture and Agri Food Canada | Papadopoulos A.P.,Agriculture and Agri Food Canada | Khosla S.,Greenhouse and Processing Crops Research Center
HortTechnology | Year: 2010

A high-wire system, in which the plant is trained into a single stem, is gaining popularity in year-round greenhouse cucumber (Cucumis sativus) production, especially with supplemental lighting, as it allows for uniform foliar and light distribution and higher yield and quality. However, this system requires much higher plant densities than the conventional umbrella system, resulting in increased crop start-up costs. A technique for raising twin-head transplants and a twin-head "V" high-wire cucumber system were developed to address this issue. The twin-head transplants were raised by topping the seedlings after the appearance of the fourth true leaf and then two strong lateral shoots were allowed to develop and be trained into a "V" system after planting. The twin-head system achieved similar plant growth and fruit yield as the conventional single-head system on two long English seedless cucumber cultivars (Bodega and Myrthos) and two breeding lines (2005A and 24-119) tested over 2 years. The twin-head system also improved the fruit grades in 'Bodega' by increasing the percentage of fruit in medium size while reducing the percentage of fruit in small size. Because the twin-head system achieved the same fruit yield as the conventional single-head system while using only half the number of transplants, we can conclude that the twin-head "V" high-wire system is a more cost-effective high-wire system for year-round greenhouse cucumber production.


Zhang T.Q.,Greenhouse and Processing Crops Research Center | Tan C.S.,Greenhouse and Processing Crops Research Center | Liu K.,Greenhouse and Processing Crops Research Center | Drury C.F.,Greenhouse and Processing Crops Research Center | And 2 more authors.
Agronomy Journal | Year: 2010

Agronomic and economic assessments of response of processing tomato (Lycopersicon Esculentum Mill.) to nutrient application with drip fertigation are essential to optimize soil fertility management that maximizes farmers' profitability in a sustainable manner. A field study was conducted to evaluate the yield and economic responses of drip fertigated processing tomatoes to additions of fertilizer nitrogen (N) and phosphorus (P) from 2003 to 2005. The experiment was arranged in a factorial design with four levels of fertilizer N (0, 120, 240, and 360 kg N ha-1) and three levels of fertilizer P (0, 100, and 200 kg P2O5 ha-1). Fertilizer N application affected biomass yield of stems and leaves, total and marketable fruit yields, N use efficiency, and N agronomic efficiency. However, neither P application nor the interaction between fertilizer N and P influenced these variables. Nitrogen use efficiency and N agronomic efficiency decreased with increases in fertilizer N rate, with N use efficiency averaging 443 kg kg-1 and N agronomic efficiency averaging 237 kg kg-1. Both fruit yields and net economic returns responded quadratically to the fertilizer N rate, with a maximum marketable yield of 127 Mg ha-1 averaged across the 3 yr. The fertilizer N rates were 271 kg N ha-1 for the maximum marketable yield and 265 kg N ha-1 for the optimum economic yield. These values are considerably greater than the current recommendation, due to the largely increased yield with drip fertigation. Fertilizer N should be applied at an increased rate for processing tomatoes with drip fertigation to maximize the economic return. © 2010 by the American Society of Agronomy.


Park H.-H.,Greenhouse and Processing Crops Research Center | Park H.-H.,National Academy of Agricultural Science | Shipp L.,Greenhouse and Processing Crops Research Center | Buitenhuis R.,Greenhouse and Processing Crops Research Center | Buitenhuis R.,Vineland Research and Innovation Center
Journal of Economic Entomology | Year: 2010

Predation, development, and oviposition experiments were conducted to evaluate Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) as a potential biological control agent for tomato russet mite, Aculops lycopersici (Massee) (Acari: Eriophyidae), which can be a serious pest of greenhouse tomatoes. Results showed that A, swirskii attacked all developmental stages of A. lycopersici and had a type II functional response at the prey densities tested. The attack rate and handling time estimates from the random predator equation were 0.1289/h and 0.2320 h, respectively, indicating that A. swirskii can consume 103.4 individuals per day. Predation rates of A. swirskii on A. lycopersici in the presence of alternative food sources such as pollen, first-instar thrips, or whitefly eggs were 74, 56, and 76%, respectively, compared with the predation rate on A. lycopersici alone. A. swirskii successfully completed their life cycle on either A. lycopersici or cattail (Typha latifolia L.) pollen. At 25°C and 70% RH, developmental time of female A. swirskii fed on A. lycopersici or on cattail pollen was 4.97 and 6.16 d, respectively, For the first 10 d after molting to the adult stage, A. swirskii fed on A. lycopersici had higher daily oviposition rate (2.0 eggs per day) than on pollen (1.5 eggs per day). From this laboratory study, it can be concluded that A. swirskii has promising traits as a predator against A. lycopersici and that their populations can be maintained using alternative food sources such as cattail pollen. We suggest that the effectiveness of A. swirskii against A. lycopersici under field conditions needs next to be investigated. © 2010 Entomological Society of America.


Cerkauskas R.F.,Agriculture and Agri Food Canada | Ferguson G.,Greenhouse and Processing Crops Research Center | Banik M.,Agriculture and Agri Food Canada
Canadian Journal of Plant Pathology | Year: 2011

Leveillula taurica was observed on field pepper at various sites in south-western Ontario in 2005-2007. The field isolates collected from these sites were similar to a greenhouse isolate based on morphological observations. Host range of greenhouse and field isolates was similar, with minor sporulation on potato, carrot and several weeds. The greenhouse pepper cultivar Samanta was the most susceptible to L. taurica while Triple 4, Duplo and Bosanova were the least susceptible to infection. Best control of pepper powdery mildew in the greenhouse was obtained with applications of myclobutanil, triflumizole, pyraclostrobin+boscalid, quinoxyfen, strobilurin derivatives (azoxystrobin, trifloxystrobin, kresoxim-methyl), copper soap, JMS Stylet-Oil ®, Valent-10118, acibenzolar-S-methyl and sulphur. Disease reduction was also obtained with applications of potassium bicarbonate, citrus oil+borax, Bacillus subtilis and a fermented milk byproduct+surfactant. K 2HPO 4+surfactant was effective in reducing disease whereas CaCl 2+surfactant, fumed silica and Sporothrix flocculosa were not effective. In field plots, best disease control was achieved with applications of myclobutanil and the fermented milk byproduct+surfactant in 2006 whereas in 2007, citrus oil+borax and potassium bicarbonate were most effective. There were no significant differences in pepper yield among the treatments in field plots. In vitro survival studies showed that the fungus was able to survive in infected pepper leaves after exposure to temperatures of 10°C for 2 months. © 2011 The Canadian Phytopathological Society.

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