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Phytophthora cactorum and Colletotrichum acutatum: Survival and Detection
Arja T. Lilja,P?ivi K. Parikka,Eila A. P??skynkivi,Jarkko I. Hantula
Agriculturae Conspectus Scientificus (ACS) , 2006,
Abstract: Phytophthora cactorum and Colletotrichum acutatum are pathogens which are transported with plant material as latent infections and can also survive in soil and plant debris. Since the beginning of 1990’s P. cactorum caused losses in strawberries in Finland and increased culling of silver birch seedlings in forest nurseries because of stem lesions. In this study primers specific for the pathogen were designed, and in a simple PCR they gave an amplification product from pure cultures only when P. cactorum was used as a template. No cross reactions were found with other Phytophthoras in group I or other microbes. Inoculated strawberry plants gave also a clear band in PCR-analyses when the template concentration was diluted. However, amplification was not always reproducible with birch seedlings. With soil samples the best result was gained by a combination of baiting and isolation. C. acutatum is a quarantine pathogen on strawberry in the European Union and thus the infected plants are destroyed in Finland to avoid further spread of the pathogen. The pathogen has earlier been found to survive over one winter in infected plant debris and soil. In the survival test (2003-2005) done in this study, specific amplification products were obtained from test plants inoculated with artificially infected plant residues after 20 months of storage outdoors on soil surface. More positive results were achieved from bait plants grown in soil collected from the field where infected plants had been destroyed two years before, than from samples collected a year after the plant destruction.
Effect of Tree Age and Various Rootstocks of Apple on Phytophthora cactorum, The Cause of Crown and Root Rot in Malakand Division  [PDF]
Jahangir Khan
Pakistan Journal of Biological Sciences , 1999,
Abstract: An extensive survey of apple orchards of different ages was conducted to explore the incidence of Phytophthora cactorum. Crown and root rot was observed on trees of all ages, but trees grown on Malling-Merton and standard (local) rootstocks during the first 3-5 years, when they first come into bearing, were most affected. As the age of the trees increased, severity and incidence of the disease decreased. Different rootstock types of apple were evaluated for their resistance to P. cactorum. Depending on various factors, all the tested rootstocks were found to be susceptible except for M-9. This rootstock, if horticulturally suitable, may provide field resistance to P. cactorum in Malakand Division.
The role of Phytophthora cactorum in decline of hydroponically- grown strawberry and evaluation of relative resistance of strawberry cultivars to it  [cached]
F. Ghaderi
Journal of Science and Technology of Greenhouse Culture , 2012,
Abstract: Phytophtora crown- and root- rot is one of the important soil-borne diseases of strawberry grown in hydroponic culture. Plant roots affected by root and crown rot show yellowish and decline symptoms and the plant perishes and dies gradually. To identify the factor responsible for strawberry crown rot, some samples were taken from infected plants. The samples were washed with tap water for 1-2 hr, blotted dry and plated on CMA. Phytophtora fungus was separated from infected tissue. Based on morphological characteristics and temperature requirement, the pathogen was identified as Phytophthora cactorum. Comparison of crown and root colonization and percent of dead seedlings showed that Selva, Aliso and Gavita cultivars had the most and the least resistance, respectively, but Kameroseh showed immune response to Phytophthora cactorum.
Identification of Phytophthora Species Associated with Stone Fruits Crown Rot in Fars Province and Reaction of Certain Rootstock to P. cactorum  [cached]
Z. Banihashemi,A. Sartipi
Journal of Science and Technology of Agriculture and Natural Resources , 2004,
Abstract: Distribution of Phytophthora species associated with stone fruits decline in Fars was investigated. Of 36 isolates of Phytophthora recovered, 23 were identified as P. cactorum (mostly from infected crown) from almond, apricot, and peach and 13 isolates of P. nicorianae from crown and basal stem of almond and apricot from different environmental conditions. The reactions of crown and root of 6- month–old local almond cultivars, i. e., Mamaee, Moheb-Ali, Talkheh e- Najafabad (Isfahan Province), Talkheh Sadeh, and Sang Talkheh Riz from Neiriz (Fars Province), peach cultivar bitter pit and apricot cultivar Hallander from Isfahan to a virulent isolate of P. cactorum were evaluated under greenhouse conditions. The inoculum of the pathogen was obtained by growing on vermiculate – hemp seed extract for 4-6 weeks and positioned around either crown or root system. Plant height, root and total weight of plants, lesion size, plant mortality, and percentage colinization of the pathogen on root and stem base were determined. The results indicated that almond cv. Mamaee was the most susceptible and almond cv. Talkheh-e-Najfabad, peach cv. bitter pit and apricot cv. Hallander were the most resistant rootstocks to P.cactorum. Comparative reactions of root and crown of various rootstocks to P. cactorum showed that although inoculation site (root or crown) in most cultivars was not significant to most characters measured, the interaction of cultivars × site of inoculation became significant for certain characters such as plant height, lesion size, root and total plant weight and mortality, indicating different reactions by root and crown to P. cactorum in some cultivars.
Distribución de Phytophthora cactorum en el perfil de un suelo cultivado con frutilla (Fragaria x ananassa)
Iribarren, María Josefina;González, Beatriz Angela;Filippini, Susana;
Summa Phytopathologica , 2012, DOI: 10.1590/S0100-54052012000100003
Abstract: phytophthora cactorum is the causal agent of leather rot, which has led to significant losses in strawberry (fragaria x ananassa) crops. this pathogen persists as oospores mainly formed in infected fruits, which remain in the soil surface. the study was carried out to investigate, after plantation removal and soil tillage, the spatial distribution of the remaining p. cactorum oospores in a representative lot for strawberry cultivation in the northeast region of the buenos aires province, argentina. sampling was performed in three blocks located along a transect diagonal to the terrain and at two depth levels in the soil profile. the topography and the soil physical parameters of interest were also evaluated. p. cactorum was detected by using baits. based on the analysis scale, there were no significant differences regarding pathogen presence at the distinct points set as samples on the soil surface; a slight tendency toward a decrease in the inoculums presence according to depth was observed. the number of positive samples in both depth, a and ab/ba, was 30 and 22 respectably in 72 samples in total. in addition, there were no significant differences in the soil apparent density, equivalent moisture and macroporosity. p. cactorum distribution on the soil surface may have been fundamentally due to natural mechanisms and soil tillage allowed the spread of viable oospores with depth.
Micropropaga??o do porta-enxerto de macieira 'Sele??o 69' tolerante à podrid?o do colo (Phytophthora cactorum)
Santa-Catarina, Claudete;Maciel, Scheila da Concei??o;Denardi, Frederico;Pedrotti, Enio Luiz;
Ciência Rural , 2001, DOI: 10.1590/S0103-84782001000500003
Abstract: the use of tolerant apple rootstocks to phytossanitary problems as the rotting (phytophthora cactorum) is able to increase the production with cost reduction. the objective of the present study is to establish in vitro micropropagation protocol of the '69 selection' rootstocks tolerant to the rotting. meristems was cultivated in vitro on ms medium supplemented with 4.4mm of 6-benzilaminopurine (bap), 2.5mm of indol butiric acid (iba), 0.3mm of giberilic acid (ga3), 3% of sucrose and 0.6% of agar. the effect of bap concentration (2.2 and 4.4mm) and the effect of culture media (ms, cheng and quoirin & lepoivre) were tested in the shoot multiplication. in the shoot elongation phase, the effects of ga3 (0; 0.5; 1.0 and 1.5mm) and iba (0; 0.5 and 1.0mm) were tested. during the rooting ex vitro and acclimatization phase, different iba concentrations (0; 1 and 2g l-1) were tested. the rate of acme meristems development was 30% of the meristems cultivated in vitro. for the shoot number, the best bap concentration was 2.2mm that provided 2.6 shoots/explant. the ms medium provided the largest shoot number for explant (2.5), however it was not differing of cheng medium (2.0 shoots/explant). for the shoot elongation phase, the ms medium supplemented 1.0mm of iba provided the largest height of shoots (23mm). in the ex vitro rooting and acclimatization phase, the 0, 1.0 and 2.0g l-1 of iba concentrations, were able to achieve on average of 77,3% of microcuttings rooting.

YOU Chun-Ping ZHENG Xiao-Bo,

菌物学报 , 2001,
Abstract: Zoospores of hybrids (five single oospore cultures) derived from intraspecific outcross resistant to metalaxyl and chloroneb and their wild-type parents(AP14 and PK9) sensitive to the both chemicals were haed respectively at the ratio 1:1,1:9 and 1:49 and smeared on 10% V6 agar plates or inoculated on apple slices. After 4 ~5 day's incubation at 25 C, the mixtures were induced to produce zoospores. About 200 single-zoospore isolates were established from each mixed culture. All of the single zoospore isolates were inoculated on 10% V6 aged plates amended with metalaxyl 20 ug/ml or chloroneb 100 ug/ml to distinguish the offsprings of hybrids from those of wild-type parents. Results showed that the percentages of offsprings from hybrids and wild-type parents in 27 out of 30 combinations grown on V6 agar were not significantly different from their expectancy values(P=0.05), and the percentages of offsprings from hybrids and wild-type parents in all of 30 combinations grown on apple slices were fitted with their expectancy values. Further, the zoospores of hybrids and their wild-type parents were mixed at the ratio 1: 1 and inoculated on 10% V 6 agar or apple slices, and the offspring percentages from the both were tested in three successive sporulating cycles. When hybrid APK-9 or APK-24 was co-cultured with wild-type parent AP14 respectively, the percentages of offsprings from hybrids were 49.1% --54.2% at the sporulating cycle 1 and decreased tO 1.8%~6.2% at cycle 3. However, when the two hybrids co-cultured with another wild-hoe parent PK9, the percentage of offspring from hybrids increased from 44.4% ~54.2% at cycle 1 to 72.1%~75.0% at cycle 3. The results from our studies suggest that the hybrids derived from intraspecific outcross in Phytophthora cactorum have vigorous competition ability with wild-type parents in vitro and in vivo, and indicate that the sexual recombination of inter-isolates may play an important part in the genetic diversity of the species.
Micropropaga o do porta-enxerto de macieira 'Sele o 69' tolerante à podrid o do colo (Phytophthora cactorum)  [cached]
Santa-Catarina Claudete,Maciel Scheila da Concei??o,Denardi Frederico,Pedrotti Enio Luiz
Ciência Rural , 2001,
Abstract: A utiliza o de porta-enxertos an es, tolerantes a problemas fitossanitários da cultura da macieira, como a podrid o do colo (Phytophthora cactorum), pode aumentar o rendimento e reduzir os custos de produ o. Com o presente trabalho, objetivou-se estabelecer um protocolo de micropropaga o do porta-enxerto 'Sele o 69', tolerante à podrid o do colo. ápices meristemáticos foram cultivados in vitro em meio de cultura MS, suplementado com 4,4mM de 6-Benzilaminopurina (BAP), 2,5mM de ácido indolbutírico (AIB), 0,3mM de ácido giberélico (GA3), 3% de sacarose e 0,6% de ágar. Foram testados o efeito da concentra o de BAP (2,2 e 4,4mM) e o efeito dos meios de cultura (MS, Cheng e Quoirin & Lepoivre) na multiplica o das brota es. No alongamento das brota es, foram testados os efeitos do GA3 (0; 0,5; 1,0 e 1,5mM) e AIB (0; 0,5 e 1,0mM). Para a fase de enraizamento ex vitro e aclimatiza o, foram testadas diferentes concentra es de AIB (0; 1 e 2g L-1). A taxa de desenvolvimento dos ápices meristemáticos cultivados in vitro foi de 30%. Para estimular a brota o, a melhor concentra o de BAP foi 2,2mM, a qual proporcionou 2,6 brota es por explante. O meio MS proporcionou o maior número de brota es por explante (2,5), porém n o diferiu estatisticamente do meio Cheng (2,0 brota es por explante). Para a fase de alongamento, o meio MS suplementado com 2,2mM de BAP e 1,0mM de AIB, proporcionou a maior altura das brota es (23mm). Na fase de enraizamento ex vitro e aclimatiza o, as concentra es de 0, 1 e 2g L-1 de AIB possibilitaram em média, 77,3% de enraizamento das microestacas.
Biochemical Changes in Green and Etiolated Stems of MM106 Apple Rootstock  [PDF]
Aysel Sivaci,Munevver Sokmen,Tohit Giines
Asian Journal of Plant Sciences , 2007,
Abstract: In the present study, total chlorophyll a, chlorophyll b, carotenoids, anthocyanin, carbohydrate, phenolic constituents, antioxidant activity and root formation percentage of MM106 apple rootstock in etiolated and green stem cuttings were investigated. The rooting studies were carried out climatic room in dark and daily period at 25°C. Chlorophyll a, chlorophyll b, carotenoids and anthocyanin contents of etiolated stems were significantly lower than green stems. Similarly, total phenolic and carbohydrate contents and antioxidant activity were found lower in etiolated stems but root formation percentage increased significantly with etiolation.
Brassica carinata for control of Phytophthora spp. in strawberry field crops
Barrau,Carmen; Porras,Maria; Romero,Eva; Zurera,Carlos; Ramos,Nídia; Soares,Celestino; Neto,Eugénia; Marreiros,António; Entrudo,José; Romero,Fernando;
Revista de Ciências Agrárias , 2009,
Abstract: soil biofumigation (sb) and soil solarization (ss) are nonchemical methods for the control of soilborne pathogens. ss uses solar radiation to heat soil and sb is based on the action of volatile compounds produced by the decomposition of cruciferae, essentially glucosinolates (gs) and isothiocyanates (itcs). brassica spp. are used as biofumigant because of their different concentrations and types of itcs that are different in their toxicity against pathogenic fungi. suppressiveness of the brassica varies between species. biofumigant effect depends on plant age and environmental growth conditions. brassica carinata, the most effective species on the in vitro control of phytophthora spp., was selected as biofumigant to evaluate and compare the ability of sb and ss to control phytophthora spp. in soil and to enhance field production of strawberry. sb with b. carinata + ss reduce p. cactorum in soil and increases strawberry yield and fruit weigh.

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