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The objective of this work was to verify the effect of electromagnetic waves on the sanitary and physiological quality of soybean seeds. The seeds were submitted to different exposure periods (0, 20, 40, 60, 80, 100, 120, 140 and 160 seconds), under electromagnetic waves with power of 900 W and frequency of 2.45 GHz, using the micro-ondas and the fungicide dicarboximide (250 g. 100 kg-1 of seeds), as an additional treatment. For the sanity test, 200 seeds were used per treatment, distributed in ten seeds per Petri dish. In the physiological test, 200 seeds per treatment were also used, distributed in 50 seeds per Germitest paper. The experimental design used was completely randomized, with ten treatments and four replications of 50 seeds each. The fungi, Aspergillus niger, Aspergillus flavus, Penicillium sp. and Fusarium sp. All periods of exposure to electromagnetic waves were efficient in reducing fungi identified in seeds. The sanitary and physiological quality was favored when the soybean seeds were exposed for up to 60 seconds, under a power of 900 W and a frequency of 2.45 GHz. The exposure of soybean seeds in periods longer than 80 seconds, under conditions of potency and frequency studied, had a negative effect on the percentage of hard seeds. [ABSTRACT FROM AUTHOR]

Thermal treatment is frequently used to overcome dormancy in forest seeds; however, it can also be used to control seed-born pathogens. This study aimed to evaluate the efficiency of thermotherapy in controlling Fusarium sp. in angico seeds [Anadenanthera colubrina (Vell.) Brenan] collected in the state of Paraíba, Brazil, and its effect on physiological quality. Nine seed sources located in the municipalities of São João do Cariri - PB, Boa Vista - PB, and Sumé - PB were selected for this study. For the sanitary test, the treatments were composed of untreated seeds (control), chemical treatment, and thermal treatment at temperatures of 50, 60, and 70 °C immersed for 10, 20, 30, and 40 minutes. The same treatments were used in the germination test, and the percentage of germination, first count, dead seeds, seedling length, and germination speed index were evaluated. The results showed that the thermal treatments effectively reduced Fusarium sp. in the seeds. Thermotherapy did not negatively affect the physiological quality of angico seeds and led to an increase in germination percentage. [ABSTRACT FROM AUTHOR]

The objective of this work was to evaluate the effect of Eucalyptus globulus essential oil on the health and physiological quality of seeds of Mimosa caesalpiniifolia Benth. and the transmission of Fusarium sp. associated with seeds. The seeds were immersed in four concentrations of E. globulus essential oil (0.25%; 0.50%; 0.75% and 1.0%). The seeds were also treated with Captana fungicide (240g for 100 kg of seeds) and immersed in sterile distilled water (control). After being treated, the seeds were evaluated by the health test, using the filter paper method (blotter test) and by the physiological quality through germination, first count, germination speed index and seedling length. The transmission of Fusarium sp. via seeds was also assessed, as it is considered potentially pathogenic. The identified fungi were: Cladosporium sp. (16.5%), Aspergillus sp. (15.5%), Fusarium sp. (7.5%), Penicillium sp. (4.0%), Rhizopus sp. (2.5%) and Periconia sp. (0.5%). The essential oil of E. globulus, in any concentration, reduced efficiently the incidence of fungi associated with M. caesalpiniifolia seeds and did not affect the physiological quality of the treated seeds. Fusarium sp. was transmitted via seeds and caused root rot and hypocotyl necrosis. [ABSTRACT FROM AUTHOR]

Seed health test prior to planting may prevent the introduction of pathogens in absence areas, provides data to farmers, certification programs, vegetal vigilance service, treatment of seeds and plant improvement. Current study evaluates the sanitary and physiological quality of cotton seeds from different producing areas in the state of Paraíba, Brazil. Seeds from different cotton cultivars were used, coupled to the producing municipality: Rubi (Juarez Távora; PB), Topázio (Juarez Távora; PB), Topázio (Remígio; PB), Aroeira (Remígio; PB), BRS 286 (Alagoinha; PB) and cotton seeds Mocó (Casserengue; PB, Sumé; PB, Quixaba; PB, São Mamede; PB and Remígio; PB). Fungi in seeds were detected by incubation through the blotter test. Physiological quality was evaluated by germination, first germination count, germination speed index, length of aerial part and root, dry matter of aerial part and root. Twenty-five fungus genera associated with cotton seeds were identified: Alternaria sp., Aspergillus spp., A. flavus, A. niger, Botryodiplodia sp., Botrytis sp., Cercospora sp., Chaetomium sp., Cladosporium sp., Colletotrichum sp., Curvularia sp., Fusarium sp., Helmithosporium sp., Monilia sp., Neorospora crassa, Nigrospora sp., Penicillium spp., Periconia sp., Phoma sp., Pytomices sp., Rhizoctonia sp., Rhizopus sp., Sclerotinia sp., Trichoderma sp. and Verticillium sp. Seeds of cultivar BRS 286 had the best health and physiological quality, whilst cotton seeds Mocó from Sumé and São Mamede had the highest occurrence rates of fungi and the lowest physiological quality. [ABSTRACT FROM AUTHOR]

The chemical control of pathogens in seeds is mainly undertaken by synthetic fungicides, although there is a need for alternatives that would not contaminate the environment and humans, with special reference to biological control by antagonists such as Trichoderma spp. Current research evaluates the influence of Trichoderma spp. on the health and physiological aspects of the seeds of Astronium urundeuva (M. Allemão) Engl. Treatments were applied by direct contact of seeds with the fungus, as blanks (asepsis only); fungicide captana® (240 g 100 kg-1 seeds) and seven different isolates of Trichoderma sp. inoculated seeds by Trichoderma sp. were conditioned on Aspergillus sp. colonies maintained during 24 h in direct contact. After treatments, seeds underwent health, germination and emergence tests. The employment of Trichoderma spp. was sufficient for reduction of Aspergillus niger occurrence in seeds of A. urundeuva and increased germination of seeds and seedlings' strength. [ABSTRACT FROM AUTHOR]

Cotton bacterial blight (CBB), caused by Xanthomonas citri pv. malvacearum, was a major disease of cotton in the United States in the early part of the twentieth century. The reemergence of CBB revealed many gaps in our understanding of this important disease. In this study, we employed a wild-type (WT) field isolate of X. citri pv. malvacearum from Georgia (U.S.A.) to generate a nonpathogenic hrcV mutant lacking a functional type-III secretion system (T3SS-). We tagged the WT and T3SS-strains with an auto-bioluminescent Tn7 reporter and compared colonization patterns of CBB-susceptible and CBB-resistant cotton seedlings using macroscopic image analysis and bacterial load enumeration. WT and T3SS- X. citri pv. malvacearum strains colonized cotton cotyledons of CBB-resistant and CBB-susceptible cotton cultivars. However, X. citri pv. malvacearum populations were significantly higher in CBBsusceptible seedlings inoculated with the WT strain. Additionally, WT and T3SS- X. citri pv. malvacearum strains systemically colonized true leaves, although at different rates. Finally, we observed that seed-toseedling transmission of X. citri pv. malvacearum may involve systemic spread through the vascular tissue of cotton plants. These findings yield novel insights into potential X. citri pv. malvacearum reservoirs for CBB outbreaks. [ABSTRACT FROM AUTHOR]

As for most plant species occurring in forests, Caesalpinia ferrea Mart. Ex Tul. has been presenting some phytosanitary problems, and thus research efforts have been increased considering the use of alternative treatments using as basis essential oils like Thymus vulgaris L., which is responsible for antimicrobial activity. The objective of this study was to evaluate the influence of the essential oil from thyme on the sanitary and physiological quality of ironwood seeds. The experiment was carried out in a completely randomized design with four repetitions with 50 seeds. The treatments considered the use of the thyme essential oil at concentrations of 0, 2, 4, 6, 8, and 10%. The ironwood seeds were obtained from matrices taken at random, moved to the laboratory, where sanitary evaluations were carried out using the Blotter test method in 25±2°C temperature and in a 12h photoperiod. After 7 days, with the aid of a microscope, fungi were identified. Next, physiological analysis were conducted -- germination, first count of germination, and germination speed index. Measurements of the shoot and root parts of the seedlings, shoot dry matter, and root dry matter were taken. According to the obtained results in this work, it was verified that the T. vulgaris dry matter in all concentrations presented different results, noting that when the oil concentration increases, the occurrence of pathogens decreases, which proves that the T. vulgaris essential oil has specific action on some genera of fungi. [ABSTRACT FROM AUTHOR]

This study was carried out towards the development of rapid PCR-based assays for detection and identification of Colletotrichum truncatum, C. gloeosporioides sensu lato and Fusarium sp. infecting green and red bell pepper seeds in Trinidad using DNA templates produced by automated grinding and robotic paramagnetic particle capture. DNA was extracted from freshly collected symptomatic green and red bell pepper seeds using Promega's Maxwell® 16 robotic system. The PCR assay of 220 seeds harvested from field-infected bell pepper fruit compared different optimization parameters including seeds that were symptomatic and asymptomatic of infection, the relative success of two different DNA polymerase enzymes, genus-specific and species-specific primers that were pre-existing in the literature in addition to primers that were newly designed for this study and duplex PCR for the simultaneous detection of DNA templates belonging to two different fungal species. The findings indicated that seeds carried dual infections of C. truncatum and Fusarium sp. Compared to other primers that were screened, our newly designed primers, ITS219-F/ITS419-R with GoTaq® Green Master Hot Start Taq DNA Polymerase, detected C. truncatum in the highest number of symptomatic seeds of infected green and red bell pepper fruit as well as in asymptomatic seeds of infected red bell pepper fruit. Fusarium sp. was detected only in red bell pepper seeds. Duplex PCR using ITS219-F/ITS419-R and Fa/Ra primers successfully simultaneously detected and identified C. truncatum and Fusarium sp. in symptomatic seeds of infected red bell pepper fruit. None of the seeds were infected with C. gloeosporioides sensu lato which is currently considered to be a minor pathogen in bell pepper in Trinidad. PCR-based detection methods are key tools in the detection and identification of fungal plant pathogens especially where seeds are an important inoculum source. The molecular approach as optimized in this study, is faster, more sensitive and the presence of single or dual fungal infections can be assessed in one assay. [ABSTRACT FROM AUTHOR]

The quality of seeds produced is the result of the management practices used and environmental conditions during growing. The aim of this study was to evaluate the physiological potential and the health of soybean seeds produced in an organic and conventional system. The genotypes UEL 110 and 122 and BRS 257 and 284 were tested in organic and conventional systems in a randomized block design. The following characteristics were evaluated: moisture content; thousand seed weight (TSW); germination (G) and first count of germination (FCG); tetrazolium (TZ); classification, length, and dry matter of seedlings; and seed health. Analysis of variance was performed separately for the management systems, followed by combined analysis. When significant, the Tukey test (p<0.05) was applied. Multivariate analysis was performed using R software. There was not significance between genotypes and management systems. The conventional management system performed positively for the characteristics TSW, G, TZ, FCG, classification, and length and dry matter of seedling roots, as well as for plant health. The UEL genotypes obtained higher TSW; UEL 110, lower germination; and BRS 257, a smaller number of ungerminated seeds and higher infestation by Cladosporium spp. The seeds produced under the organic system have greater weight and lower infestation by contaminants, whereas the conventional system produces seeds of better physiological quality and lower contamination by Phomopsis and bacteria. The genotype BRS 257 may have seeds multiplied in the organic and conventional management systems. [ABSTRACT FROM AUTHOR]

The fungi Aspergillus sp., Penicillium sp., Fusarium sp. and Stenocarpella macrospora are pathogens frequently associated with the complex of diseases responsible for spike rot and incidence of burned grains in susceptible hybrids. In view of the above, the objective of this study was to evaluate the influence of the percentage of burned grains on the sanitary quality of corn grain lots (Zea mays L.), from the field of production and submitted to irrigation and two sowing systems. The experimental design was completely randomized, with four treatments (lot I = with irrigation and conventional seeding system, lot II = with irrigation and direct seeding system, lot III = no irrigation and conventional seeding system, lot IV = no irrigation and no-tillage system), in four replications. The corn grain lots were evaluated for the percentage of burned grains and the incidence of fungi (Blotter test). There was a significant difference between the different corn grain lots for all analyzed variables. The highest percentage of burned grains and the incidence of fungi Penicillium sp., Fusarium sp. and Aspergillus sp. were observed in the lots from the production fields conducted with irrigation. The higher the percentage of burned grains, the higher the incidence of fungi Penicillium sp. and Fusarium sp., in the corn grain lots, these variables showed a high positive correlation between the percentage of burned grains and incidence of fungi. [ABSTRACT FROM AUTHOR]

Rodents influence plant establishment and regeneration by functioning as both seed predators and dispersers. However, these rodent–plant interactions can vary significantly due to various environmental conditions and the activity of other insect seed predators. Here, we use a combination of both field and enclosure (i.e. individual cage and semi‐natural enclosure) experiments, to determine whether rodents can distinguish sound seeds from those infested with insects. We also demonstrate how such responses to insects are influenced by food abundance and other environmental factors. We presented rodents with 2 kinds of Quercus aliena seeds (sound and insect‐infested seeds) in a subtropical forest in the Qinling Mountains, central China, from September to November of 2011 to 2013. The results showed that rodents preferred to hoard and eat sound seeds than infested seeds in the field and semi‐natural enclosure, while they preferred to eat infested seeds over sound seeds in the individual cages. In addition, both hoarding and eating decisions were influenced by food abundance. Rodents hoarded more sound seeds in years of high food abundance while they consumed more acorns in years of food shortage. Compared with field results, rodents reduced scatter‐hoarding behavior in semi‐natural enclosures and ate more insect‐infested seeds in smaller individual cages. These results further confirm that rodents distinguish infested seeds from non‐infested seeds but demonstrate that this behavior varies with conditions (i.e. environment and food abundance). We suggest that such interactions will influence the dispersal and natural regeneration of seeds as well as predation rates on insect larvae. [ABSTRACT FROM AUTHOR]

Pythium seedling blight, which can be caused by a number of Pythium spp., is a disease that affects soybean (Glycine max) in the United States and Canada. Pythium ultimum var. ultimum, one of the most common pathogenic species, is favored by cool, wet conditions in early spring and causes seed decay, root rot, and seedling damping-off. In all, 102 major ancestors of modem North American cultivars and "first progeny" cultivars developed directly from ancestral lines were evaluated for resistance to P. ultimum var. ultimum and two other species of Pythium in greenhouse assays. Several ancestors and first progeny cultivars, as well as the resistant check Archer, had varying levels of partial resistance to an Illinois isolate of P. ultimum var. ultimum. In a subsequent experiment, four of the most resistant lines (PI 84637, Maple Isle, Fiskeby 111. and Fiskeby 840-7-3) and the susceptible cultivar Kanro were screened for resistance against isolates of P. irregulare and P. sylvaticum, and resistance to P. ultimum var. ultimum was confirmed. The lines that were partially resistant to P. ultimum var. ultimum in the first experiment were also partially resistant to P. irregulare and P. sylvaticum. The P. ultimum var. ultimum isolate was the most aggressive of the three isolates, followed by the P. irregulare and P. sylvaticum isolates. Modern cultivars descended from the soybean lines with partial resistance to these pathogens could be useful sources of resistance to Pythium seedling blight if they are found to have similar levels of resistance. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the transmissibility of Fusarium oxysporum f.sp. vasinfectum by inoculated cottonseeds. The cottonseeds were inoculated using the water restriction technique, at different times of exposure. A completely randomized design was used in the laboratory and a randomized design with blocks was used in the field experiment, with a 2x5 factorial arrangement with two cultivars (FMT 701 and Delta Opal) and five times of exposure of the pathogen in seeds (0 h, 24 h, 48 h, 72 h and 96 h). There was a reduction in the percentage of germination with the increase of the infection of the seeds when in greater time of contact with the fungus. Delta Opal cultivar presented minor disease index and major pathogen incidence when compared to FMT 701 cultivar. The rates of infection and transmission of the seed pathogen were effective and directly proportional to the inoculum potential in the seeds, with rates of 95% and 1.2%, respectively. [ABSTRACT FROM AUTHOR]

An experiment was conducted during 2014-2015 to standardize the seed testing method in Kabuli chickpea MNK-1 by number of seeds and number of germination papers. Among the different testing methods 25 seeds per replication recorded highest seed germination percentage (91.58%), less number of fresh un-germinated seeds (1.91%), abnormal seedlings (4.00%), diseased seeds (2.33%) and significantly higher seedling vigour index-I and II (2215 and 6863), among the number of germination papers used 2+1 as in between paper method(Bottom 2 and one paper above) recorded significantly higher germination percentage (92.12%), less number of fresh un-germinated seeds (1.41%), abnormal seedlings (3.66%), diseased seeds (2.33%) and significantly higher seedling vigour index-I and II (2463 and 6900), when compared to other. Irrespective of number of germination paper and seeds used however, interaction of 25 seeds per replication and 2+1 between paper method of seed germination testing showed significantly germination percentage (96.50%), less number of fresh un-germinated seeds (0.00%), abnormal seedlings (1.00%), diseased seeds (1.00%) and significantly higher seedling vigour index-I and II (2844 and 7792) followed by 50 seeds per replication. [ABSTRACT FROM AUTHOR]

One of the rarer problems that occur in growing medicinal and spice plants is ensuring the quality of the propagating material. Germination of seeds of one of these plants, Allium ursinum L., is slow. To improve that, stratification is used. In the experiment, which was carried out in Lithuania in 2016, evaluation of four-and five-week long stratification and the use of alkaline ionized (pH 8.6) water for germination affect for Allium ursinum L. seeds were evaluated. It was found that the above-mentioned intervals for stratification did not affect the beginning of seed germination. Furthermore, one of the possible reasons for slower germination was found, and it was the incidence of seed diseases caused by fungi and bacteria. Allium ursinum L. seeds were affected the most by Penicillium ssp. micromycetes. The longer the period of stratification, the more alkaline ionized water decreased the effect of Mucor ssp. Micromycetes. [ABSTRACT FROM AUTHOR]

This study was conducted to estimate the infection of Bruchophagus roddi in 66 alfalfa fields in Igdir, Turkey during the month of August in 2014-2015, and to determine infection preferences of B. roddi for number of pods in a bunch (NPB) and number of seeds in a pod (NSP). CHAID algorithm was preferred in the prediction of the number of seeds damaged (NSD) through district, year, NPB and NSP. In Aralik district, B. roddi preferred the seeds of varieties with NSP⩽3.8 (0.858 NSD) at lower rate in 2015. In Karakoyunlu, Tuzluca and Central districts in 2015, varieties with NPB>11 were preferred less but varieties with 910 were preferred less but varieties whose NSP was greater than 7.6 were preferred at the highest proportion by B. roddi in Aralik district in the 2015. [ABSTRACT FROM AUTHOR]

It is widely accepted that the loss of function of different cellular proteins following their aggregation into highly stable aggregates or the gain of pathologic function of the resulting macromolecular assemblies or both processes are tightly associated to distinct debilitating neurodegenerative diseases such as Alzheimer's, Parkinson's, Creutzfeldt-Jacob, Amyotrophic Lateral Sclerosis and Huntington's diseases. How the aggregation of one given protein leads to distinct diseases is unclear. Here, a structural-molecular explanation based on the ability of proteins such as α-synuclein or tau to form assemblies that differ by their intrinsic architecture, stability, seeding capacity, and surfaces is proposed to account for distinct synucleinopathies and tauopathies. The shape and surfaces of the seeds is proposed to define at the same time their seeding capacity, interactome and tropism for defined neuronal cells within the central nervous system. [ABSTRACT FROM AUTHOR]

Transmission studies of Pyricularia graminis-tritici by wheat seed can help establishing pathogen tolerance standards in crops. Four genotypes, each one with different responses to blast, were inoculated with five volumes of fungal suspension (1,5x105 spores.mL-1), in order to obtain 0, 5, 10, 20 and 30% of plants inoculated in the experimental unit. The potential of transmission of P. graminis-tritici from plant to seed was evaluated by the incidence of the fungus in the seeds produced. Under controlled conditions, the transmission rate of the fungus from seed to seedling was evaluated. Blast incidence in field allowed a high incidence of P. graminis-tritici in the seeds, especially in the genotypes considered susceptible. The transmission of fungus from the seeds to seedlings occurred 7, 14 and 21 days after sowing, at low rates. There was a relationship between the presence of blast in field and the incidence of P. graminis-tritici in seeds produced by the genotypes BRS 264, VI 98053, CD 116 and CD 104. Inoculation of 5, 10, 20 and 30% of plants with fungus can generate a high incidence of the pathogen in field and in the seeds produced, but it doesn't guarantee a high transmission rate from seed to seedling, which is low under controlled conditions. [ABSTRACT FROM AUTHOR]

Bacterial seed and boll rot disease is a newly emerging threat to the cotton growers. Disease prediction model was devised to predict the disease progression impacted by the vector (Dysdercus cingulatus) and environmental variables (maximum air temperature, minimum air temperature, relative humidity and rainfall) on four varieties to minimise its losses and disease management cost. Impact of a-biotic environmental variables (maximum and minimum air temperature, relative humidity and rainfall) was assessed on bacterial seed and rot of cotton disease and its vector (D. cingulatus) on FH-941, FH-942, MNH-886 and FH-114 cotton varieties. Maximum red cotton bug population was assessed at 29–31 °C maximum temperature and at 15–17 °C minimum temperature. Disease severity was noticed maximum when maximum and minimum temperature was measured at 28–29 °C and 13–14.5 °C, respectively. Vector population was maximum when relative humidity and rainfall were 63–66% and 1.50–2.5 mm, respectively. Relative humidity at 66–68% and 0.5–1.5 mm rainfall favoured disease development. With increase in number of bugs, increase in disease severity was noted, maximum disease severity 45–48% noticed when 7–8 bugs were recorded. Red cotton bug (Dysdercus cingulatus) population prediction model was devised based on a-biotic factors (maximum and minimum air temperature, relative humidity and rainfall) on four cotton varieties. Disease forecasting model was developed based on biotic (D. cingulatus) and a-biotic factors. A close resemblance between observed and the predicted red cotton bugs and disease severity was seen. [ABSTRACT FROM AUTHOR]

Castor-derived products are currently used for protecting agricultural crops and seeds from devastating damages of pests and diseases. Extracts (1-10%) of leaf or seed in water or chemical solvents, and crude oil (3-5%) extracted from seed were found effective as sprays against foliage insect pests. Populations of the root-knot nematodes were significantly reduced when de-oiled seed cake was incorporated into soil at 1000 kg/ha, especially after mixing it with bio-inoculants such as, a fungus ( Poecilomyces lilacinus) or a bacterium ( Pasteuria penetrans). Castor proved as a potential synergist when mixed with other plant products or chemical pesticides and exhibited different modes of actions but with comparatively limited insecticidal properties. In less developed and developing countries, the common use of oil is for treating stored cereals and pulses at 5-10 ml/kg seed. In both field and greenhouse experiments, pest mortality and other biological parameters were dose-dependent. This review discusses different uses of castor products to foresee possibility of replacing or at least reducing use of toxic chemicals in crop and seed protection. [ABSTRACT FROM AUTHOR]

The bacterial infection of seeds is one of the most important quality factors affecting yield. Conventional detection methods for bacteria-infected seeds, such as biological, serological, and molecular tests, are not feasible since they require expensive equipment, and furthermore, the testing processes are also time-consuming. In this study, we use the Raman hyperspectral imaging technique to distinguish bacteria-infected seeds from healthy seeds as a rapid, accurate, and non-destructive detection tool. We utilize Raman hyperspectral imaging data in the spectral range of 400-1800 cm-1 to determine the optimal band-ratio for the discrimination of watermelon seeds infected by the bacteria Acidovorax citrulli using ANOVA. Two bands at 1076.8 cm-1 and 437 cm-1 are selected as the optimal Raman peaks for the detection of bacteria-infected seeds. The results demonstrate that the Raman hyperspectral imaging technique has a good potential for the detection of bacteria-infected watermelon seeds and that it could form a suitable alternative to conventional methods. [ABSTRACT FROM AUTHOR]

Background: Southern rice black-streaked dwarf virus (SRBSDV) has spread from the south of China to the north of Vietnam in the past few years, and has severely influenced rice production. However, previous study of traditional SRBSDV transmission method by the natural virus vector, the white-backed planthopper (WBPH, Sogatella furcifera), in the laboratory, researchers are frequently confronted with lack of enough viral samples due to the limited life span of infected vectors and rice plants and low virus acquisition and inoculation efficiency by the vector. Meanwhile, traditional mechanical inoculation of virus only apply to dicotyledon because of the higher content of lignin in the leaves of the monocot. Therefore, establishing an efficient and persistent-transmitting model, with a shorter virus transmission time and a higher virus transmission efficiency, for screening novel anti-SRBSDV drugs is an urgent need. Methods: In this study, we firstly reported a novel method for transmitting SRBSDV in rice using the bud-cutting method. The transmission efficiency of SRBSDV in rice was investigated via the polymerase chain reaction (PCR) method and the replication of SRBSDV in rice was also investigated via the proteomics analysis. Results: Rice infected with SRBSDV using the bud-cutting method exhibited similar symptoms to those infected by the WBPH, and the transmission efficiency (>80.00%), which was determined using the PCR method, and the virus transmission time (30 min) were superior to those achieved that transmitted by the WBPH. Proteomics analysis confirmed that SRBSDV P1, P2, P3, P4, P5-1, P5-2, P6, P8, P9-1, P9-2, and P10 proteins were present in infected rice seedlings infected via the bud-cutting method. Conclusion: The results showed that SRBSDV could be successfully transmitted via the bud-cutting method and plants infected SRBSDV exhibited the symptoms were similar to those transmitted by the WBPH. Therefore, the use of the bud-cutting method to generate a cheap, efficient, reliable supply of SRBSDV-infected rice seedlings should aid the development of disease control strategies. Meanwhile, this method also could provide a new idea for the other virus transmission in monocot. [ABSTRACT FROM AUTHOR]

Seeds can be considered one of the most efficient forms to disseminate pathogens. Therefore, the use of healthy seeds is extremely important to establish a crop, and seed health testing must be performed to determine the seed sanitary quality. This study aimed to compare the efficiency of seed health testing to detect Pyricularia grisea and Fusarium graminearum in three samples of wheat seeds. Methods evaluated were Blotter test with freezing (BTF) and potato-dextrose-agar culture medium (PDA). The incubation temperatures were 20 °C and 25 °C. From each sample, a subsample was submitted to seed asepsis using hypochlorite solution (1%) and another analyzed without seed asepsis. The temperatures evaluated did not influence the detection of the pathogens. P. grisea incidence ranged from 4.5 to 17% with BTF without seed asepsis. The BTF with seed asepsis and PDA (with and without seed asepsis) presented pathogen incidence no higher than 1.5%. Moreover, results suggested that most part of P. grisea inoculum was presented externally on seed tissues. PDA medium was more efficient to detect F. graminearum, independently of seed asepsis. By this method, pathogen incidence ranged from 3 to 39%. F. graminearum incidence using BTF with seed asepsis varied from 0.5 to 1.5% and BTF without seed asepsis presented a pathogen incidence of 5.0 to 12.5%. The Blotter test with freezing was more efficient to detect P. grisea while the PDA medium was more efficient to detect F. graminearum. [ABSTRACT FROM AUTHOR]

Given what is already known in regard to seed health and the availability of molecular methods for detection of the pathogens Stenocarpella maydis and Stenocarpella macrospora in maize seeds, Colletotrichum gossypii var. cephalosporioides in cotton seeds, and Corynespora cassiicola in soybean seeds, the aim of this study was to evaluate seed vigor according to different inoculum potentials. The fungus isolates were inoculated on seeds by the technique of water restriction, through which different inoculum potentials are obtained, corresponding to times of seed exposure of 0, 24, 48, and 96 hours for maize and cotton seeds, and 0, 36, 108, and 144 hours for soybean seeds. The seeds were subjected to germination, electrical conductivity, health, and qPCR tests. Results of the blotter test showed that in most pathosystems, there was a higher incidence of the fungi with an increase in inoculum potential. A decrease in germination percentage was observed in all species as inoculum potential increased, as well as further degradation of seed membranes. The qPCR test confirmed that the most damaged seeds in the tests had higher presence of the pathogens. [ABSTRACT FROM AUTHOR]

Ray blight disease of pyrethrum (Tanacetum cinerariifolium) is caused by Stagonosporopsis tanaceti, with infected seed being a major means of transmission of this fungal pathogen. The infection process of S. tanaceti in pyrethrum seed and seedlings was determined. Infection hyphae only infected the outer and inner layers of the seed coat and not the embryo of naturally infected pyrethrum seed. During the process of germination of infected seed, S. tanaceti from the seed coat infected the developing embryo and cotyledon, resulting in pre- and post-emergence death, depending on the level of infection in the seed coat. Pre-emergence death occurred due to disintegration of the infected embryo, which was replaced by hyphae and extracellular anthocyanin-like material (EAM) at 7 days after incubation (dai). Post-emergence death occurred after both epidermal and cortical tissues of infected cotyledons at the crown/hypocotyl region disintegrated due to colonization by hyphae. Moreover, most of the tissues of the vascular bundles and cortical tissues contained heavy depositions of EAM at 10-14 dai. In 6-week-old infected seedlings, hyphae were confined to the epidermis and the cortical tissues at the crown/hypocotyl regions; the vascular bundles of both infected and uninfected regions, and cortical tissues of the uninfected regions of the seedlings were completely free from infection hyphae and EAM. These findings provide a better understanding of the early stages of the disease cycle of S. tanaceti and will lead to improved control measures for seedborne infection using seed treatments. [ABSTRACT FROM AUTHOR]

BACKGROUND There is a need to minimize economic damage by sorting infected seeds from healthy seeds before seeding. However, current methods of detecting infected seeds, such as seedling grow-out, enzyme-linked immunosorbent assays, the polymerase chain reaction (PCR) and the real-time PCR have a critical drawbacks in that they are time-consuming, labor-intensive and destructive procedures. The present study aimed to evaluate the potential of visible/near-infrared (Vis/NIR) hyperspectral imaging system for detecting bacteria-infected watermelon seeds. RESULTS A hyperspectral Vis/NIR reflectance imaging system (spectral region of 400-1000 nm) was constructed to obtain hyperspectral reflectance images for 336 bacteria-infected watermelon seeds, which were then subjected to partial least square discriminant analysis (PLS-DA) and a least-squares support vector machine (LS-SVM) to classify bacteria-infected watermelon seeds from healthy watermelon seeds. The developed system detected bacteria-infected watermelon seeds with an accuracy > 90% (PLS-DA: 91.7%, LS-SVM: 90.5%), suggesting that the Vis/NIR hyperspectral imaging system is effective for quarantining bacteria-infected watermelon seeds. CONCLUSION The results of the present study show that it is possible to use the Vis/NIR hyperspectral imaging system for detecting bacteria-infected watermelon seeds. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

A collection of 102 Diaporthe isolates was compiled from lesions on carrot, parsley and wild Apiaceae species in France from 2010 to 2014. Molecular typing based on ITS rDNA sequences resulted in the identification of 85 D. angelicae and 17 D. eres isolates. Based on sequences of the 3′ part of the IGS rDNA, intraspecific variability was analysed for 17 D. angelicae and 13 D. eres isolates from diverse plant species, locations in France, and plant tissues. The genetic diversity was greater for D. angelicae isolates than D. eres isolates. In vitro sensitivity of five D. angelicae and four D. eres isolates to each of nine fungicides was similar for isolates of both species, with a marked variation in fungicide sensitivity depending on the active ingredient. To assess the pathogenicity of D. angelicae and D. eres isolates on carrot, one isolate of each species was inoculated onto umbels in a controlled environment. Typical lesions were observed for both isolates. Carrot crop debris collected from a seed production field in France and placed in controlled conditions produced perithecia and ascospores typical of Diaporthe, that were further characterized molecularly as belonging to D. angelicae. Detection of Diaporthe species on seed lots from three carrot production fields in France was investigated. Both species were detected on seeds by conventional PCR assay, with a greater frequency for D. angelicae than D. eres (67% vs 33%, respectively). Overall, the results highlighted that umbel browning in carrot seed crops in France was mainly caused by D. angelicae. [ABSTRACT FROM AUTHOR]

The present study was conducted to detect seed borne mycoflora associated with seven cultivars of sunflower (Helianthus annuus L.) and five cultivars of Zinnia (Zinnia elegans L.) by using Agar and Blotter paper methods. A total 12 genera of fungi were detected including; Alternaria alternata, Aspergillus flavus, Aspergillus niger, Cladosporium sp., Stemphylium helianthi, Penicillium sp., Fusarium oxysporum, Mucor sp., Fusarium moniliforme, Fusarium solani, Rhizocotonia solani and Rhizopus sp. The detected fungi depleted germination 10-30%, 10-20% and seedling mortality 10-17%, 10-12%. in sunflower and Zinnia respectively. A comparative study was designed to evaluate three fungicides to control seed mycoflora at the rate of of 1.5g/kg, 2.0g/kg, 2.5g/kg, 3.0g/kg, Maximum germination percentage was attained in case of seed dressing with Topsin M-70 followed by Bayton and Dithane M-45 at the rate of 3.0g/kg. [ABSTRACT FROM AUTHOR]

Plant diseases caused by different kinds of microorganisms either carried through air, water or present in soil, seeds or propagative planting materials have adverse impact on agriculture production and economy worldwide. Apart from other crops vegetables are also subjected to several seed borne fungal, bacterial and viral pathogens, which cause substantial yield loss upto 10 percent in Pakistan. This article gives vast information regarding significance and prevalence of various kinds of seed borne mycoflora (Alternaria solani, Fusarium oxysporum, F. solani, Botrytis cineria, A. alternata, Chaetomium globosum, Curvularia lunata, Aspergillus niger, Drechslera specifer and Rhizoctonia solani) particularly associated with seeds of tomato. These mycoflora are causative agents of devastating tomato diseases like early blight, fusarium wilt and foot rots, grey mold, root and fruit rots. A range of conventional and modern techniques employed for seed borne fungal detection and different control strategies including chemical and biological methods opted by researchers have been reviewed in present paper. A variety of factors like availability of susceptible plants, favorable environmental conditions and overhead irrigation are serious constraints for plant disease development. Under these conditions, monitoring of plant health and detection of diseases particularly using seed detection assays to screen infested seed lots before planting provide effective disease management strategy. [ABSTRACT FROM AUTHOR]

An efficient DNA extraction protocol and polymerase chain reaction ( PCR) assay for detecting Leptosphaeria maculans from infected seed lots of oilseed rape were developed. L. maculans, the causal agent of blackleg, a damaging disease in oilseeds rape/canola worldwide, was listed as a quarantine disease by China in 2009. China imports several millions of tons of oilseeds every year. So there is a high risk that this pathogen will be introduced to China via contaminated seeds. Seed contamination is one of the most significant factors in the global spread of phytopathogens. Detection of L. maculans in infected seed lots by PCR assay is difficult due to the low level of pathogen mycelium/spores on seeds and PCR inhibitors associated with the seeds of oilseed rape. In our study, these two major obstacles were overcome by the development of a two-step extraction protocol combined with a nested PCR. This extraction protocol (kit extraction after CTAB method) can efficiently extract high-quality DNA for PCR. Amplification results showed that the detection threshold for conventional PCR and nested PCR was, respectively, 1 ng and 10 fg of DNA per μl in mycelia samples. On contaminated seed lots of oilseed rape, the detection threshold of conventional and nested PCR was 709 fg/ μl and 709 ag/ μl of DNA, respectively. The DNA extraction protocol and PCR assay developed in this study can be used for rapid and reliable detection of L. maculans from infected seeds of oilseed rape . [ABSTRACT FROM AUTHOR]

Claviceps purpurea is an important ovary-infecting pathogen that replaces seed with sclerotia in Kentucky bluegrass grown for seed. Sclerotia overwinter in the soil and germinate in the spring to produce ascospores that infect grass seed ovaries. To better understand environmental conditions affecting ascospore production, the effects of preconditioning cold treatment and subsequent incubation temperature on germination of sclerotia were determined in growth chambers under controlled conditions. Preconditioning cold treatment was essential for germination only in treatments where the incubation temperature was high (at least higher than 20°C). At lower incubation temperatures (10 to 20°C), preconditioning also played a role in improving sclerotial germination. Preconditioning at 4°C (in darkness) for 4 to 8 weeks followed by incubation at 10 and 20°C (cycle of 12 h each of darkness and light), or constant 15°C (cycle of 12 h each of darkness and light), was optimal for ergot germination. When sclerotia were preconditioned for 4 weeks or longer, number of incubation days required for initiation of germination was not affected by temperature in the range from 10 to 25°C (cycle of 12 h each of darkness and light), although the duration of germination (or the progress speed of germination) was still affected by temperature. A simple model was developed based on laboratory results and validated with historic spore trap data collected from various Kentucky bluegrass fields in Oregon (Willamette Valley, central Oregon, and Grande Ronde Valley). The prediction model could predict ascospore onset well and explained 55% of variation in the data. [ABSTRACT FROM AUTHOR]

A trial was conducted in the experimental field of the Institute of Forage Crops, Bulgaria, over the period 2012-2014 with alfalfa wich grew for seed production. It was studied the action of three insecticides (two biological/NeemAzal T/S and Pyrethrum FS EC/and one synthetic insecticide Nurelle D - standard) to a control of lucerne seed weevil, Tychius flavus Beck. (Coleoptera: Curculionidae); alfalfa plant bug, Adelphocoris lineolatus Goeze (Hemiptera, Heteroptera: Miridae) and pea aphid, Acyrthosiphon pisum Harr. (Hemiptera, Sternorrhyncha: Aphididae) - major pests in alfalfa seed production. The method of sweeping with entomological net was used. Organic products were most effective against A. pisum. Increasing efficacy of NeemAzal reached satisfactory values of 67.8 and 69.1 percent of the seventh and ninth day after the application. Pyrethrum exhibited strong efficacy throughout the reporting period in the range 73.9-82.8% and differences between bioinsecticides were significant. In compared with standard its toxic action after the fifth day was approached the effect of synthetic insecticide with minor differences between them. Bioinsecticides exhibited good control against A. lineolatus as the trend of the better protective effect of Pyrethrum was retained. A dominant influence on the efficacy variation and seed productivity had the type of insecticide followed by factors year of treatment. The productivity of alfalfa grown for seed production realized after application of Pyrethrum significantly exceeded control and was comparable to that of Nurelle D. [ABSTRACT FROM AUTHOR]

The fungus Corynespora cassiicola, causal agent of target spot in soybeans, can be transmitted by soybean seeds and as of that point cause severe damage. This disease may be diagnosed at an early stage by seed testing, but knowledge in this area is insufficient. Because of that and increased attack by the disease in soybean areas in Brazil, further studies are required. The aim of this study was to evaluate the use of conventional PCR in detecting C. cassiicola in soybean seeds. The GA4-F/GA4-R primers described in the literature were tested for their specificity and sensitivity for detection of C. cassiicola in pure culture and in soybean seeds. Uninoculated and inoculated seed samples were used with different incidence levels 100%, 10%, 1%, 0.5%, 0.25%, and 0% of preestablished inoculum potentials, P0, P1, P2, and P3. Detection of C. cassiicola in P1 inoculum potential was observed in samples with incidence levels of 10% to 100%. In the P3 potential, detection of the pathogen was successful in samples at the low level of 0.25%. [ABSTRACT FROM AUTHOR]

The present study was aimed to investigate the effect of modified atmosphere with elevated levels of CO2 against pulse beetle, C. chinensis in stored horse gram. Seeds were artificially infested with C. chinensis and exposed to CO2 (30%, 40% and 50 %) and packed in air tight containers. Concentrations of 40% and 50% CO2 not only checked seed infestation but also checked the progeny production of pulse beetle and reduced the weight loss of seed compared to normal atmosphere. Storage of horse gram seeds in CO2 rich atmosphere also maintained seed quality without any detrimental effect on germination and seedling vigor up to six months of storage. [ABSTRACT FROM AUTHOR]

[Objective] The aim was to explore the effects of cultivation and seed reservation methods on quality and disease/insect damages of maca seed in cold highland areas, providing scientific references for cultivation and seed reservation and planning of maca vareity. [Method] Yelow, purple and black maca were selected and cultivated in the region with an elevation of 3000 m to be experimental materials and cultivation and seed reservation methods were as folows: maca seed reservation in situ, seed reservation in original soils maca grown after selection of macaballs, and seed reservation in the region with an elevation of 2700 m after selection of macaball, seed reservation in greenhouses in the region with an elevation of 2400 m after selection of macabal, and growing selected balls in greenhouses and transplanting to the farmlands with an elevation of 2 400 m. [Result] The cultivation and seed reservation methods had significant or extremely significant effects on maca phenological phase; maca in different colors were treated by different cultivation and seed reservation methods, showing insignificant effects on disease and insect damages. [Conclusion] It can be concluded that the selected maca balls stored for 15 dasper the method grown in the region with an elevation of 2700 m will improve seed quality and reduce disease or insect damages. [ABSTRACT FROM AUTHOR]

The incorporation of biological control organisms in seeds may help control pathogens and improve seedling performance. The aim of this study was to determine the effects of biopriming bean seeds withTrichodermaspp. andBacillus subtilisusing physiological conditioning, suspensions of biological structures and film coating techniques. Biopriming treatments with suspensions of biological structures were performed using the commercial products Agrotrich plus®and Rhizoliptus®. Water restriction was achieved using a PDA + Manitol (−0.7 MPa) medium for bothTrichodermaspp. andBacillus subtilis. Fifty disinfected bean seeds were placed in each petri dish. When the first radicle protrusion appeared in a seed, the other seeds were removed and dried in the laboratory environment for 48 h. Film coating was performed with the addition of the Color Seed®(150 mL kg−1) polymer to a treatment solution containing either theTrichodermaspp. or the Rhizoliptus product. Seeds were dried for 48 h in the laboratory. Seeds were covered and treated with one or both organisms. Biopriming with spore or bacterial cell suspensions promoted bean seedling growth, and the other techniques were not required to potentiate these benefits. Covering the primed bean seeds reduced seed quality. BothTrichodermaspp. andBacillus subtilispromote bean seedling growth, benefitting the seedling even after it becomes independent of the seed reserves. [ABSTRACT FROM AUTHOR]

Application of rapid and time-efficient health diagnostic and identification technology in the seed industry chain could accelerate required analysis, characteristic description and also ultimately availability of new desired varieties. The aim of the study was to evaluate the potential of multispectral imaging and single kernel near-infrared spectroscopy (SKNIR) for determination of seed health and variety separation of winter wheat (Triticum aestivum L.) and winter triticale (Triticosecale Wittm. & Camus). The analysis, carried out in autumn 2013 at AU-Flakkebjerg, Denmark, included nine winter triticale varieties and 27 wheat varieties provided by the Faculty of Agriculture and Life Sciences Maribor, Slovenia. Fusarium sp. and black point disease-infected parts of the seed surface could successfully be distinguished from uninfected parts with use of a multispectral imaging device (405–970 nm wavelengths). SKNIR was applied in this research to differentiate all 36 involved varieties based on spectral differences due to variation in the chemical composition. The study produced an interesting result of successful distinguishing between the infected and uninfected parts of the seed surface. Furthermore, the study was able to distinguish between varieties. Together these components could be used in further studies for the development of a sorting model by combining data from multispectral imaging and SKNIR for identifying disease(s) and varieties. [ABSTRACT FROM AUTHOR]

The aim of this study was to underscore that seed treatment by the fog of ozonated water constitutes a promising alternative tool, in terms of health and environmental gains, regarding traditional ozone treatment. In order to obtain a clear vision of this performance, the technology was implemented on an industrial scale (malting industry). Under an exposition of barley seeds to 9.8 ppm of dissolved ozone into water, our results showed a significant disinfection effect of 80% forFusarium sp. and 70% forAspergillus sp., but no effect was established onAlternaria sp. [ABSTRACT FROM PUBLISHER]

The cosmopolitan warm-climate plant pathogen Lasiodiplodia theobromae was isolated from two sources: Seeds of Tetrapleura tetraptera from Nigeria and fruits of Cocos nucifera from Mexico; the former instance is novel for host, the latter a novel geographic record for infection of coconut fruits. Per cent germination of T. tetraptera seeds was negatively and significantly correlated with per cent infection by the fungus. Repeated tests with isolates from both coconut and Tetrapleura confirmed pathogenicity of all tested isolates to coconut fruit. [ABSTRACT FROM AUTHOR]

Determination of the capability of common bean “amachamiento” (Aphelenchoides besseyi Christie) of being seed-transmitted. The objective of this research was to determine the capability of Aphelenchoides besseyi of being seed-transmitted in common bean. During 2007 and 2008, seeds were collected from nematode-infested common bean plants (cv. Cabécar) previously showing characteristic symptoms, in commercial plantations of the Brunca region of Costa Rica (southeastern area of the country). Between September 2008 and September 2009 the seeds were sowed in plastic pots in a greenhouse located in Veracruz, Pérez Zeledón, Costa Rica. Once seeds germinated, plants were observed weekly to determine the appearance of “amachamiento” symptoms and detect the cases of disease transmission by seed. To support the previous work, seeds from “amachamiento” diseased plants (cv. Cabécar) were collected in commercial common bean plantations in five localities of the Brunca region of Costa Rica in 2014. The seeds were carried to Estación Experimental Agrícola Fabio Baudrit Moreno of Universidad de Costa Rica located in Alajuela, where they were examined in a laboratory to determine the presence of A. besseyi specimens. Contrary to indicated for A. besseyi in rice and pastures, crops in which this pathogen is seed-transmitted, in common bean it was not possible find specimens of this nematode nor diseased plants from seeds of infested plants. The results obtained indicate that, under these experimental conditions, seeds are not an effective way for the transmission and dissemination of the “amachamiento” disease in common bean. [ABSTRACT FROM AUTHOR]

Bamboo is one of the renewable natural resources and plays significant role in livelihood of rural people. Its propagation through seeds is efficient and cost effective but development of appropriate storage technique is extremely useful for prolonging seed viability. Seeds were processed, sealed in polythene bags and stored in air tight containers under 4°C, 16°C and ambient temperature. Effect of leaf extract/fungicides on seed-borne mycoflora was evaluated. Periodical viability tests were conducted to evaluate shelf-life of seeds. Seeds stored at 4°C and 45±5 % relative humidity had maintained viability for 36 months with 52 % germination. Occurrence of mycoflora was minimal on seeds treated with Neem leaves/Mancozeb 75% WP and stored at 4°C. It could be inferred from the study that the best conditions for storage of bamboo seeds to extend shelf-life is air tight container under 4°C with 45±5 % relative humidity. [ABSTRACT FROM AUTHOR]

Four experimental trials were carried out in order to evaluate the efficacy of different products (chemicals, resistance inducers and natural products) as well as heat air when applied to basil seeds naturally infested by Peronospora belbahrii, the causal agent of downy mildew of basil, a pathogen which is seed transmitted. Seed quality, as vigour index, was also evaluated. In general, seed treatment had a positive effect on the reduction of disease incidence and on plant biomass at the end of each trial, with very satisfactory results when disease incidence was lower than 10% and still satisfactory results with a higher disease incidence. Although many of the fungicides, resistance inducers and thyme oil treatments tested showed a significant disease reduction compared with the untreated control, the protection offered was only partial. Moreover, the effectiveness of the tested seed treatments varied considerably between the trials. The seeds treatment with heat air (65°C for 10 min) significantly reduced the number of infected plants per container. The interaction effect between the fungicides (at the lowest dosage tested, with the exception of acibenzolar-S-methyl, and dimethomorph), thyme oil and the heat air treatment was also significant. In terms of biomass, most treatments not significantly improved the fresh weight in comparison with the untreated control. The highest biomass was observed in the plots where seeds were dressed with mancozeb combined with heat air. Interestingly, thiram is also effective against other pathogens affecting basil and the thermal treatment and potassium phosphite are fully compatible with the rules of organic farming. Seed dressing represents the starting point of a full integrated approach for downy mildew management. [ABSTRACT FROM AUTHOR]

Population-based threshold models using hydrothermal time (HTT) have been widely used to model seed germination. We used HTT to model conidial germination and mycelial growth for the seed pathogen Pyrenophora semeniperda in a novel approach to understanding its interactions with host seeds. Germination time courses and mycelial growth rates for P.semeniperda were measured on PDA amended to achieve a series of five water potentials (ca. 0 to −6 MPa) at six constant temperatures (5–30 °C). Conidial germination was described with alternative population-based models using constant or variable base and maximum temperature and water potential parameters. Mycelial growth was modeled as a continuous, linear process with constant base temperature and base water potential. Models based on HTT showed reasonable fit to germination and growth rate data sets. The best-fit conidial germination model (R 2 = 0.859) was based on variable base and maximum temperature as a function of water potential. The good fit of the linear mycelial growth model (R 2 = 0.916) demonstrated the utility of HTT for modeling continuous as well as population-based processes. HTT modeling may be a useful approach to the quantification of germination and growth processes in a wide range of filamentous fungi. [ABSTRACT FROM AUTHOR]

In 2011, a new Fusarium wilt of Papaver nudicaule was observed in a commercial nursery near Ventimiglia (Imperia province, northern Italy) as well as in the Regional Institute of Floriculture (I.R.F.) of Sanremo (Imperia province, northern Italy). Molecular analysis enabled identification of the causal agent as a new forma specialis called Fusarium oxysporum f. sp. papaveris. The origin of the infection was found on P. nudicaule seeds. However, disinfection with sodium hypochlorite was able to eliminate the pathogen infection. Virulence of ten isolates obtained from seeds was evaluated by pathogenicity assay. The more virulent strains were analyzed by phylogenetic analysis on the basis of the EF-1α, pg1 and pgx4 genes. Sequences obtained by PCR amplification were aligned with other formae speciales of Fusarium oxysporum from the GenBank and used in the construction of the phylogenetic trees. Seed infections have been observed in the case of many vegetable crops; however, this phenomenon has been less studied in the case of ornamental crops. As a consequence of seed exchanges or transmission via infected seeds, new and old pathogenic species of Fusarium are continuously introduced into new areas and production systems. [ABSTRACT FROM AUTHOR]

A total of 105 seed samples collected from commercially available potato seed lots in Turkey were assayed for Verticillium dahliae. V. dahliae was successfully isolated from 29 of the 105 seed lots tested. The frequency of infected lots was nearly 28%. Vegetative compatibility of the isolates was assessed through complementation tests using nitrate non-utilizing mutants. Of the 110 isolates obtained, 63 were assigned to VCG4A, 24 to VCG4B, 19 to VCG2A and one to VCG2B, while the three remaining isolates could not be assigned to any of the identified VCGs. All 36 of the isolates tested in the greenhouse on potato cv. 'Russet Burbank' were pathogenic to potato. As a group, AUDPC values were significantly higher ( P <0.05) for VCG4A than for VCG4B and VCG2 isolates. These data suggest that (i) commercial potato seed lots are commonly infected with V. dahliae, and that this is a primary method by which the pathogen can be introduced into production fields; (ii) potato isolates of V. dahliae belong to VCG4A, 4B and 2A and these isolates are widely distributed via seed lots; and (iii) VCG4A and VCG4B are distinct pathotypes of V. dahliae that vary in their aggressiveness to potato. The present study is the first report of natural infections of potato by VCG4A and VCG2A in Turkey. [ABSTRACT FROM AUTHOR]

Fusarium oxysporum f. sp. phaseoli (Fop) is a devastating pathogen that can cause significant economic losses and can be introduced into fields through infested Phaseolus vulgaris (common bean) seeds. Efficient seed health testing methods can aid in preventing long-distance dissemination of this pathogen by contaminated seeds. In order to improve detection of Fop in seed, a rapid, accurate and sensitive real-time PCR assay (q PCR) protocol was developed for detection of Fop in common bean seeds. Seed lots of seven cultivars with infection incidence ranging from 0·25 to 20% were prepared by mixing known amounts of Fop-infected seeds with Fop-free seeds. Direct comparisons between SYBR Green and Taq Man q PCR methods were performed using primers based on the Fop virulence factor ftf1. The primers developed in this study produced a 63 bp product for highly virulent strains of Fop but did not produce an amplicon for nonpathogenic or weakly pathogenic isolates of F. oxysporum from P. vulgaris or other hosts. Under optimized conditions, both q PCR assays detected Fop infection at low levels (0·25%); however, the results suggest the Taq Man assay was more reliable at quantification than the SYBR Green assay. Linear regression models were fitted to the relationships between results of q PCR assays and infection incidence, but the models differed among cultivars. Fungal biomass per seed differed among cultivars and was related to seed size. The results indicate that the Taq Man assay developed in this study is a useful tool for the detection and quantification of Fop in bean seeds. [ABSTRACT FROM AUTHOR]

Papaya meleira virus ( PMeV), the causal agent of papaya sticky disease, was first reported in Brazil and more recently in Mexico. Yield losses in papaya ( Carica papaya) orchards related to this virus can be considerable over relatively short time spans. To date, very little is known regarding the transmission mechanisms of PMeV, which has made it difficult to effectively control the virus and to prevent dissemination. A few published reports have claimed that PMeV is not seed-transmissible. However, in this study, evidence is presented for seed transmission of PMeV in papaya cultivar Maradol. Three seed materials (whole dry seed, seed coat and embryo-endosperm) from Maradol were analysed using reverse transcription-polymerase chain reaction. A seed transmission rate of c. 81% was observed, suggesting that this mechanism is an important route of virus dissemination. For the first time, this study shows that PMeV is seedborne and can be transmitted to the next generation through contaminated papaya seeds. [ABSTRACT FROM AUTHOR]

Diplodia sapinea is one of the major pathogens of pines worldwide. Despite the putative critical importance of seed infection in the epidemiology of the disease, this aspect of the biology of the fungus is poorly known. Here, biological and molecular methods were developed for the detection of the fungus and applied to assess D. sapinea infection in Corsican pine seeds. A buffered medium containing tannic acid and malt extract as a nutrient base was the most efficient and selective for D. sapinea recovery. A molecular method based on DNA extraction with a commercial kit and specific amplification, including an internal amplification control, was developed. A high percentage of infection (57% positive isolations) was observed in seeds obtained from fallen cones in a Corsican pine stand with no apparent symptoms of D. sapinea. Seeds collected from trees in a seed orchard showing severe symptoms of dieback caused by D. sapinea had comparatively lower infection (38%). Moreover, very low infection levels (1-5%) were observed after the standard treatment used for seed extraction, which included heating at 40°C. Diplodia sapinea was not recovered from seedlings grown from infected seed lots submitted to water stress. Overall, results suggest that the risk of disease transmission by commercial seeds is probably low, but could be further reduced by thermotherapy. [ABSTRACT FROM AUTHOR]