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1.
Corynebacterium sepedonicum was detected in symptomless potato stems and tubers with immunofluorescence using monoclonal antibodies specific for the bacterial ring rot pathogen. The concentration of bacterial cells in potato tissue preparations ranged from >500 cells/microscope field to 1 cell per preparation. Symptomless tubers containing ring rot bacteria planted in field plots yielded plants with ring rot symptoms, plants with latent ring rot infections, or plants with no detectable levels of ring rot bacteria. Tubers with the greatest number of bacteria were most likely to develop plants expressing ring rot symptoms, but even some seed tubers with a low number of bacteria developed into plants with symptoms. Some seed tubers with high levels of ring rot bacteria produced plants with only low numbers ofC. sepedonicum. 相似文献
2.
Summary Plants were grown in the field from seed pieces of potato cultivars injected with ring rot bacteria (Corynebacterium sepedonicum). Symptoms were produced with both 18 and 180 colony forming units (cfu) on cvs Norchip and Red Pontiac and with 180 cfu
on cv. Belrus plants. Tuber symptoms were detected in all cultivars except Belrus and Teton. Tuber progeny produced plants
that developed top symptoms on all cultivars except those of cv. Nooksack, Russet Burbank, and Teton. Tuber progeny of the
second crop produced both plants and tubers with symptoms developing only in the cv. Nooksack. In another 3-year experiment,
variability in the disease response of selected cultivars and lines was examined following knife-inoculation of tuber seed
with a high level of ring rot bacteria. Significant correlations between top and tuber symptoms were detected, but they were
not high enough to make unnecessary the examination of both top and tuber symptoms in ring rot disease selection studies.
Contribution no. 3879111 相似文献
3.
Various potato cultivars were grown in field plots from seed pieces inoculated withCoryneacterium sepedanicum by vacuum infiltration. Foliage symptoms were recorded during the growing season and tuber symptoms at harvest. Cultivars were ranked according to the frequency with which the progeny tubers expressed external bacterial ring rot symptoms. Those that yielded 50–100% symptomatic tubers were placed in symptom expression class (SEC) 1; those that produced 25–49%, 10–24%, and ≤9% symptomatic tubers were placed, respectively, in SEC 2,3, and 4. The incidence of latent ring rot infections in stems and tubers were similar among cultivars in the different SEC classes. Bacterial population densities, quantified by immunofluorescence, were as high as 1010 cells/g in stems from cultivars of all SEC classes. Mean populations in tubers ranged from 106 – 107 cells/g and did not differ significantly among cultivars. 相似文献
4.
Effect of the ring rot pathogen and latent potato viruses on ring rot symptoms and yield of potatoes
The ring rot bacterium,Corynebacterium sepedonicum (Spieck. and Kotth.) Skapt. and Burkh., and latent potato viruses (potato virus S and potato virus X) were investigated for their effect on ring rot symptom development on potato plants in the greenhouse and on symptom development and yield of potatoes in the field. Both virus-free (VF) and virus-infected (VI) Red Pontiac stem cuttings root-inoculated with ring rot bacteria in the greenhouse developed typical (T) ring rot symptoms, and symptom severity did not differ between VF and VI plants. In a field study, both VF and VI Russet Burbank seed pieces knife-inoculated with ring rot bacteria produced plants with atypical (A) and T ring rot symptoms as well as a combination of both types. The data suggest that more A than T symptoms develop on VI plants and more T than A symptoms develop on VF plants. Combined infection with the ring rot pathogen and the latent potato viruses resulted in greater yield losses of total and marketable Russet Burbank tubers than infection with the bacterial or viral pathogens alone. 相似文献
5.
K. Mansfeld-Giese 《Potato Research》1997,40(2):229-235
Summary Plant-to-plant transmission of the bacterial ring rot (BRR) pathogen,Clavibacter michiganensis subsp.sepedonicus (Spieck. et Kott.) Skapt. et Burkh. of potato (Solanum tuberosum L.), was studied in field trials over a three year period. Healthy and infected seed tubers were planted 35 cm apart. In
one treatment, a subsurface barrier was placed between the healthy and infected seed tubers separating the root systems of
neighbouring plants. In this treatment, none of 216 plants grown from healthy seed tubers was infected at harvest, as determined
by indirect immunofluorescence antibody staining (IFAS) with monoclonal antibodies. In the other treatment, no subsurface
barrier was used. In this treatment, two of 368 plants (0.5%) grown from healthy seed tubers were infected at harvest. It
is concluded that plant-to-plant transmission may occur but at very low frequency, and is unlikely to play a significant role
compared with the potential of transmission by shared potato handling equipment. 相似文献
6.
G. A. Nelson 《American Journal of Potato Research》1985,62(1):23-28
The survival ofCorynebacterium sepedonicum, the bacterial ring rot pathogen, in infected potato stems and on burlap surfaces held at various freezing and above-freezing temperatures was investigated by root-inoculating potato stem cuttings with aqueous suspensions prepared from these materials. Infectious bacteria were recovered from dried Russet Burbank stems held for 44 mo in an unheated machine shed and from dried Warba stems held for 55 mo. Inoculum from dried stems of all cultivars held for 63 mo did not incite symptoms; however, inoculum from Russet Burbank stems incited symptomless infection in 10% of the inoculated plants. This 63-mo survival period exceeds a 26-mo survival period previously reported. Ring rot bacteria survived and remained infectious for at least 18 mo on burlap surfaces subjected to temperatures of ?40° to ?5°C, alternating temperatures of -5° to 5°C, or a constant temperature of 5°C. Inoculum from burlap stored at the lower temperatures caused the most severe symptoms. These results stress the need for keeping crop debris away from potato operations and for using proper decontamination procedures to maintain potato seed stocks free of ring rot. 相似文献
7.
The latex agglutination test was evaluated for detection of the potato bacterial ring rot pathogen,Corynebacterium sepedonicum. The bacterium was detected in infected potato stems and tubers tested and in inoculated eggplant stems. Test reliability was confirmed using blind tests. A minimum of 106 bacterial cells/ml was requisite for observable agglutination. Nonspecific reactions were not observed from healthy extracts of plant tissues. Nonspecific reactions with other bacteria maintained in pure culture were eliminated by addition of bovine serum albumin to sensitized latex preparations. 相似文献
8.
S. H. De Boer J. Van Vaerenbergh D. E. Stead J. D. Janse A. R. McKenzie 《Potato Research》1992,35(2):217-226
Summary Potato stems and tubers grown in the field from seed tubers inoculated withClavibacter michiganensis subsp.sepedonicus, which causes bacterial ring rot, were tested by indirect, sandwich enzyme-linked immunosorbent assay (ELISA) in five laboratories.
Correlation between values for each experimental treatment from the five laboratories was greater (r=0.86) than correlation between values for individual samples (r=0.71). When three or more laboratories obtained ELISA values of ≥0.200 for a sample, that sample was presumed to be positive.
Conversely, when three or more laboratories obtained ELISA values <0.200, the consensus determination was regarded as negative.
The percentage of stem and tuber samples that were in agreement with the consensus ELISA determination varied from 65.5 to
96.7%. Indirect immunofluorescence tests, conducted on the same samples in two laboratories, were consistent with 83.4–91.9%
of the consensus ELISA determinations. Presence or absence ofC.m. sepedonicus was confirmed in some samples by an eggplant bioassay and direct isolatiion of the bacterium. The ELISA procedure was well
suited for screening large numbers of samples and this study confirms it to be a promising procedure in routine indexing of
seed potatoes forC.m. sepedonicus. 相似文献
9.
G. A. Nelson 《American Journal of Potato Research》1980,57(12):595-600
The survival of the ring rot bacterium,Corynebacterium sepedonicum, on contaminated surfaces and in infected stems was investigated by root inoculating potato stem cuttings with aqueous suspensions prepared from these materials. The pathogen survived for 24 mo on contaminated surfaces of burlap, kraft paper, and polyethylene plastic held at 12% relative humidity (RH) at either 5 or 20°C. It persisted for less than 14 mo on surfaces held at 94% RH at either temperature. Infectious ring rot bacteria were also recovered from dried, infected potato stems held for 26 mo in an unheated machine shed. These results emphasize the importance of strict sanitation and disinfestation procedures in maintaining potato seed stocks free of bacterial ring rot. 相似文献
10.
Summary High grade potato seed tubers of three cultivars were inoculated in Scotland by vacuum infiltration in suspensions ofErwinia carotovora subsp.carotovora and subsp.atroseptica in different combinations, and transported to Valencia, Spain. They were cut into two to three pieces and planted in January
1984, 1985 and 1986 in fields furrow irrigated before and after emergence. High incidences of blanking and blackleg were associated
with seed inoculated with high numbers ofE.c. atroseptica alone or together withE.c. carotovora and not with high or low numbers ofE.c. carotovora alone.E.c. atroseptica predominated at emergence in March in rotting seed pieces which failed to produce a plant, regardless of the seed treatment,
and in diseased stems in April but it was replaced byE.c. carotovora in May. The levels of blanking and blackleg after inoculating 16 cultivars with both erwinias were not correlated between
years nor were they significantly different within years among most of the cultivars. 相似文献
11.
S. H. De Boer 《American Journal of Potato Research》1991,68(2):107-113
The bacterial ring rot disease of potato (Corynebacterium sepedonicum) can be detected in seed potato lots by serological tests with greater accuracy than by visual field inspections. Indexing tests can make use of highly specific immunofiuorescence probes, enzyme-linked immunosorbent assays, and perhaps other procedures. Sensitivity and specificity of these procedures need to be determined in order to estimate the confidence with which ring rot can be detected in a seed lot. In addition to the laboratory tests, the sampling strategy determines the efficacy and sensitivity of the indexing procedure. Samples might consist of stems, leaf petioles, or tubers in single or composite units. Disease incidence and number of plants sampled also determine the confidence level with which ring rot can be detected in a potato seed lot. Although research has been conducted on many aspects of ring rot testing procedures, further work needs to be done. Nevertheless, it is anticipated that indexing potato seed lots for the presence of ring rot will be a significant factor in control and eradication of the disease. 相似文献
12.
Kuo-Ching Tzeng Raymond G. McGuire Arthur Kelman 《American Journal of Potato Research》1990,67(5):287-305
Mechanically harvested tubers of 14 potato cultivars grown on both loamy sand and silt loam soils were evaluated for resistance to bacterial soft rot caused byErwinia carotovora subsp.atroseptica. Cultivars were also assayed for calcium and dry matter content to determine possible correlations with soft rot resistance. Resistance of potato tubers to bacterial soft rot was assayed after harvest by inoculating tubers and determining percent surface area decayed after four days in a mist chamber. Tubers of the cultivars differed widely in resistance to bacterial soft rot. The ranking of the resistance of tubers from different cultivars to bacterial soft rot was similar for both soils, although disease severity in tubers from a particular soil type varied with the season. Of the cultivars tested, tubers of Butte, Russet Burbank, and Nor-gold Russet were ranked as the most resistant, whereas tubers of Redsen, Norchip, Norland and Belchip were rated as the most susceptible. Tubers of Rhinered, Red La Soda, Superior, Pontiac, Atlantic, and Nooksack were intermediate in resistance. Neither calcium concentration in medullar tissues nor dry matter of potato tubers alone could be correlated with ranking of the cultivars with respect to severity of bacterial soft rot. However, a multiple linear regression model incorporating both variables indicated that tubers with a high content of both calcium and dry matter were likely to be less susceptible to bacterial soft rot than were tubers with lower percentages of these variables. 相似文献
13.
The presence ofClavibacter michiganensis subsp.sepedonicus was detected by immunofluorescence and ELISA in diluent in which cores from 200 potato tubers had been incubated on a rotary shaker. By this procedure the ring rot pathogen was detected in composite samples from naturally infected tubers and tuber samples “spiked” with infected tissue or a pure culture of the pathogen. Populations of saprophytic bacteria increased about 100-fold in the diluent during 18 h of incubation but did not interfere with serological detection of C.m. sepedonicus. Some of the results suggest thatC. m. sepedonicus cells multiply during incubation of tuber samples. Extraction of ring rot bacteria from potato tuber tissue by incubation on a rotary shaker requires little work and minimizes the amount of plant tissue in the extract compared to the standard extraction procedure involving maceration and differential centrifugation. 相似文献
14.
Tubers from eight potato cultivars (cvs) grown at two different locations in Wisconsin were tested for bacterial soft rot resistance using different inoculation techniques. The procedures included 1) point inoculations of tubers with different inoculum levels followed by incubation in ambient or low oxygen condtions, 2) inoculation of mechanically bruised tubers followed by incubation in a mist chamber, and 3) a standard slice inoculation method. The point titration test followed by incubation in dew chamber and the mist chamber-bruise test showed similar patterns of resistance for cultivars that were used in these experiments. These two methods are considered to be effective for screening potato tubers for bacterial soft rot resistance. Point titration methods are very useful if only limited numbers of tubers are available. The mist chamber-bruise test is simpler than the other procedures; however, to obtain reproducible results large numbers of tubers are required. Because of the great variability of the results obtained in inoculation of slices, the reliability of this approach can be questioned as a standardized method for evaluation of resistance. Tubers of somatic hybrids ofS. brevidens andS. tuberosum and their sexual progeny were significantly more resistant to bacterial soft rot than tubers of moderately resistant cultivars when evaluated by each of the assay procedures. 相似文献
15.
Summary Available information has been reviewed on tuber resistance toP. infestans, its inheritance and breeding procedures used to obtain potato cultivars superior in this character.
P. infestans is worldwide the most destructive potato pathogen. Tuber resistance is an essential component of potato resistance as this
pathogen is often responsible for tuber rot in storage, and infected tubers of susceptible cultivars provide an important
way for its overwintering.
In Europe many cultivars and advanced breeders selections have been obtained with tuber resistance toP. infestans, but in the last decades no progress is noted in the mean level of this resistance in cultivars. The expression of tuber
resistance depends to a large extent on testing conditions and therefore it can be difficult to evaluate. Consequently making
progress in breeding is not easy, and also cultivar assessment data from various countries sometimes differ considerably.
It is concluded from published data that it should be easier to make progress in breeding potato cultivars with resistant
tubers if more attention is paid to combining the various types of resistance which are already known, and if the genetic
determination of durable resistance toP. infestans is better understood.
Professor Dr. K.M. Świeżyński passed away on 27th July 2000 相似文献
16.
Summary Survival of the pathogen causing silver scurf of potato (Helminthosporium solani) in Alberta soils was studied by evaluatingH. solani infection in the progeny ofH. solani-free nuclear seed potato tubers planted in fields where potatoes had never been grown or were grown 1, 2, 3, or 4 years previously.
Daughter tubers from all the fields developed silver scurf lesions, andH. solani was isolated from infected tubers. This is the first report of survival ofH. solani in Alberta soils. Soil-borne inoculum appears to have a role in the epidemiology of the disease and in the introduction of
the pathogen into silver scurf-free potato seed stock. Of 31 plant species tested, only potato was found to be a host ofH. solani. Most of theH. solani isolates from north central Alberta were more sensitive to thiabendazole than those from southern Alberta, where thiabendazole
is much more commonly used. 相似文献
17.
In order to determine proper selection criteria for tuber yield in potato clones obtained from true potato seed (TPS) and
to evaluate relationships between tuber yield and its components, an investigation was conducted using the five check cultivars
Agria, Marfona, Draga, Agata, and Arinda, and 120 potato clones obtained from TPS. The study was conducted in an augmented
randomized complete block design with three replications. Yield and its components were recorded. Correlation coefficient
analysis showed that tuber yield had significant positive associations with number of tubers per plant, average weight per
tuber (tuber size), plant height, diameter of main stem, and number of main and secondary stems per plant, whereas its correlation
with tuber dry-matter concentration was significantly negative. Number of tubers per plant, tuber size, and plant height had
significant standardized partial regression coefficients with very small tolerance and large variance inflation factor (VIF)
values. These were considered as the first-order variables in sequential path analysis. 相似文献
18.
Summary Over 2 years, seed tubers or stems were inoculated withFusarium sulphureum Schlecht. (F. sambucinum Fuckel f. 6 Wollenw.) and the incidence of dry rot on daughter tubers assessed by standardised wound tests. The amount of
stem and soil inoculum was also measured in one year.
Inoculating stem bases resulted in greater concentrations of spores on the stem bases, greater soil populations at harvest
and more dry rot on tubers than inoculating the seed tuber. Overall, the incidence of dry rot and the amount of stem and soil
inoculum was similar for the three methods of haulm destruction: cutting and removing the stems, applying sulphuric acid or
applying diquat dibromide to the growing plants. 相似文献
19.
20.
Alan W. McKeown 《American Journal of Potato Research》1990,67(11):761-768
Several of the recently released early-potato (Solanum tuberosum L.) cultivars used in Ontario have produced uneven stands which have been shown to be a result of delayed emergence from basal end seed pieces. A study was conducted to evaluate the effects of seed portions on the yield of three early potato cultivars, Jemseg, Superior and Yukon Gold. Yield of plants from basal seed pieces was lower than that from apical seed pieces or whole tubers for Jemseg and Yukon Gold during several sequential harvests. With Superior, cut seed portions yielded less than whole seed. Number of stems per plant was lower for basal plants of Jemseg. Tubers with strong apical dominance or dormancy such as Jemseg and Yukon Gold are prone to differences in yield among seed portions. 相似文献