Search

Copyright of Investigación Agraria is the property of Investigacion Agraria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bactericera cockerelli Sulc, the potato / tomato psyllid (Solanum tuberosum and S. lycopersicum), is recognized as a threat to the production of solanaceous crops because it is an efficient vector of the bacterium Candidatus Liberibacter solanacearum (CaLso) in the American continent, Europe, and New Zealand. The biological and genetic characteristics of the insect make its management difficult, and so do the high number of host, refuge. and feeding plants in which it can be found. Furthermore, the influence of climate change has caused psyllid populations to establish and colonize new areas and countries. At present, the psyllid vectors of microorganisms that cause diseases in plants are widely distributed, and studies are being carried out to understand the impact of their populations on intensive agricultural production systems. In the last decade, studies on the application of new biological control and management techniques have also increased aiming to count on fast and efficient alternatives for reducing the effects on crops and economy. A total of 74 scientific papers related to the host plants of these insect vectors, their biological and chemical control strategies, and the novel alternatives for their management were analysed. In order to maintain surveillance over the vector, the present status of the identification of these species in Cuba, the situation concerning the presence of the cultivation system. -psilid-CaLso in the world and the American and Caribbean regions, as well as the possible implications of the presence of these species for the Cuban agriculture were studied in depth. [ABSTRACT FROM AUTHOR]

Global food security could be threatened in the coming years by the emergence and spread of emerging pests in crops. Psyllids are considered as possible destructive pests due to their relationships with some important plant pathogens. Bactericera cockerelli Sulc (Hemiptera: Triozidae) is recognized as an efficient vector of the bacterium Candidatus Liberibacter solanacearum (CaLsol), an invasive pest according to the EPPO, which causes diseases in potatoes, tomatoes, peppers, and other solanaceous and some apiaceous crops. Known the vector-bacteria complex to be present in different countries of the world belonging to the American continent, Europe and New Zealand, 61 scientific papers related to this topic were reviewed. Changes in the climatic variables, the biological distribution of this insect-vector system, the high ecological plasticity that allows this insect to develop different biotypes, depending on the characteristics of the area where it develops, could complicate the control of the insect-pathogen system. These characteristics make necessary a maintained extreme surveillance in those countries where it is not yet present. So far, the bacterium and the vector are not present in Cuba; however, its proximity to countries where it is present, the existence of optimal climatic conditions host plants, and the increasing tourism and international trade, make necessary to offer updated information on this disease, the causal agents and their vectors as a contribution to the preparation of the scientific-technical-productive personnel and other decission makers. [ABSTRACT FROM AUTHOR]

Copyright of Agriscientia is the property of Revista AgriScientia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The goal of this research was to assess alternatives of biofertilization with Fosfotic, Safermycorrhiza, and their combination in the potato variety Superchola under semi-controlled conditions. The experiment was carried out in a greenhouse and the substrate used was a typical Andisol of the region. A Completely Randomized Design was used with three replications. These alternatives and their combinations with the NPK dose that is used in the region and with different reductions of it, were evaluated, forming a total of 23 treatments. The best integral results were obtained with the treatments in which mineral fertilization is combined with some of the biofertilization alternatives (Fosfotic and Safer-mycorrhizas), with which it is suggested that these studies be continued under field conditions in the Andisols of Carchi -Ecuador. It is demonstrated that both the inoculations with Fosfotic and Safer-mycorrhizas, as well as their joint inoculation, can constitute viable alternatives in the cultivation of potatoes in these soils. However, the reduction of the mineral fertilizers without combine that with biofetilizers implies a reduction of the production, so it is not recommendable. [ABSTRACT FROM AUTHOR]

Taking into account the need to produce potato seed (Solanum tuberosum L.) with low inputs, this work was carried out with the aim of to determine the effect of the Versaklin® bioproduct on Early Blight (Alternaria solani Sorauer) in the production of potato (Solanum tuberosum L.) cv. 'Romano' seed. Minitubers obtained as basic seed were used. A field experiment was designed with three treatments: application of Versaklin®, chemical products and control without application of products. The incidence and intensity of the disease were determined, the area under the disease progression curve (AUDPC) was calculated and the technical effectiveness of the culture was estimated with Versaklin® or chemical products. In addition, the number of tubers per plant was quantified, the fresh and dry mass of the tubers were determined and it were classified by their diameter (caliber). Treatment with Versaklin® reduced incidence (30%) and disease severity (23.0%). The AUDPC was found in a value between control and chemical treatment. The superiority of the chemical treatment was verified by its technical efficiency and the potential of Versaklin® use because it reached a value that represents 60% of chemical treatment but with only one product. The number of tubers per plant had no significant differences among treatments. The highest proportion of tubers of caliber to be used as seed (35-45 mm) occurred in the treatment with Versaklin®. The results indicated that Versaklin® bioproduct could be part of disease management strategies. [ABSTRACT FROM AUTHOR]

Nine potato cultivars (BRS Eliza, BRS Ana, Epagri 361-Catucha, SCS 365 Cota, BRS Clara, BRSIPR Bel, Iapar Cris, Agata and Asterix) were evaluated for resistance to eight root-knot nematode species (Meloidogyne spp.). Plants were grown in greenhouse pots containing sterilized soil and inoculated with 5,000 eggs + secondstage juveniles (J2) of M. javanica (Est J3 and J2a), M. incognita (Est I2), M. arenaria (Est A2), M. enterolobii (Est M2), M. paranaensis (Est P1), M. hapla (Est H1), M. morocciensis (Est A3), or M. graminicola (Est VS1). Fifty-five days after inoculation each plant was assessed for the number of galls and number of eggs + J2, and the nematode reproduction factor (RF) was estimated. According to our study, all cultivars were susceptible to all root-knot nematode species tested except for M. graminicola. The cultivars that were less susceptible to M. javanica were Catucha, Eliza, and Cris; to M. incognita, Agata; to M. hapla, Eliza; to M. arenaria, Cota, Clara, Asterix, Ana, Eliza, and Agata; to M. enterolobii, Bel and Asterix; to M. paranaensis, Catucha, Bel, Agata, Asterix, Cota, Clara, and Ana; and to M. morocciencis, Agata. To M. graminicola, the cultivars Eliza, Cris, and Asterix were immune, and Agata and Catucha, resistant. [ABSTRACT FROM AUTHOR]

The aim of this work was to evaluate the techniques TAS-ELISA and IC-RT-qPCR as detection tools for Potato virus Y (PVY) in foliar tissues of potato (Solanum tuberosum L.). Leaf samples of the potato variety Diacol-Capiro from three different plots in northern Antioquia (Colombia) were used. Additionally, the complete genome sequence of this virus was obtained using Next-generation sequencing (NGS). PVY detection using both techniques differed significantly in sensitivity, as 88.8% of the samples tested positive for PVY using IC-RT-qPCR in contrast to only 33.3% with TAS-ELISA. Sanger sequencing of the RT-qPCR amplicons and the comparison with the melting temperatures of the positive control (77.5°C±1°C) were used to confirm the presence of PVY. Bioinformatics analysis resulted in a contig of 9701 nt with an average sequence depth of 716x. The PVY_Yarumal contains an ORF coding for a 3061 residue protein flanked by 5' and 3' untranslated regions of 187 and 328 nt, respectively. Phylogenetic analysis using the complete polyprotein CDS and CP regions suggests phylogenetic identity with necrotic strain PVYNTN; sequence motifs K400E419and QELA typical of PVYNTN were also found in PVY_Yarumal. These results suggest that urgent measures are required to strengthen current integrated virus disease management in the potato agroindustry in Colombia by using highly sensitive detection techniques based on real-time RT-PCR. [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Biotecnología is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ralstonia solanacearum (Rs) causes the disease quarantine called bacterial wilt in potatoes. Mexico importseed from United States of America (USA) and Canada, which is a significant aspect to eventual introduction of the disease in areas with large tracts of potato. Sonora is an important region in relation to potato production. Therefore, this research was conducted, with the following objectives: a) production of antibody for Rs; b) diagnosis of Rs in foreign tuber, and in tuber for human consumption which is used for seed; c) detection of Rs in vegetative growth of potato lots in Sonora, Mexico. We analyzed seed, seedling, leaf and tuber; the detection methods used were: specific means, ELISA, antiserum produced and pathogenicity tests. The positive results have shown the presence of Rs in tubers for consumption; in foreign tuber and vegetative stages it was negative. The separate testing should not be used as a unique method of detection; the presence of Rs, represents a risk of eventual manifestation of the disease, so it is necessary to undertake activities with preventive phytosanitary control. [ABSTRACT FROM AUTHOR]

The production of Solanum tuberosum L., Lycopersicum esculentum Mill. and Physalis ixocarpa Brot. (Solanales: Solanaceae) is prone to economic loses because of the presence of Bactericera cockerelli Sulc., which is related to the Purple Top and "zebra chip" diseases, and is also considered a vector of Candidatus Liberibacter solanacearum. The alternatives of control have been inefficient because none of them have considered the spatial behavior of the insect inside the plot. Such behavior would allow focusing the control alternatives, making them more efficient. The purpose on this work was to model the spatial distribution of the eggs, nymphs and adults of B. cockerelli which were obtained in potato field by transects samplings, by using geostatistics tools. The results indicate that the spatial distribution of the populations of eggs, nymphs and adults of B. cockerelli type was aggregated in each sampling date. The cross validation of the semivariograms corroborates the aggregated distribution of eggs, nymphs and adults of B. cockerelli. The generated maps allow observing the aggregated structure of the insect population, letting identify both infested areas and not-infested areas. Spatiotemporal stability was found for the three stages of the insect. [ABSTRACT FROM AUTHOR]

Copyright of BIOAGRO is the property of Revista BIOAGRO and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In 1956, Tecia solanivora was reported by the first time in Central America. This Lepidopteran insect of the Gelechiidae family was found to severely damage potato crops (Solanum tuberosum), which adversely affected local economy. Although this insect has reduced mobility, it has invaded several countries in Central and South America as well as the Canary Islands in Spain. The damage caused by T. solanivora has been detected in both field crops and stored tubers. The economic impact of the pest in countries of the Andean area is much more serious than in Central America, mainly because potato is an important family staple and production is very intensive. Therefore, T. solanivora is considered the most damaging crop insect pest in such countries. This review focuses on the actual scientific knowledge on T. solanivora, which includes its origin and spread across different countries, implications, strategies for controlling its impact. In addition, current knowledge generated from phylogeography and population genetics of T. solanivora are discussed as complementary strategies to deal with this pest. [ABSTRACT FROM AUTHOR]

The productions of potato (Solanum tuberosum L.) have gotten main economic looses due to the presence of Bactericera cockerelli Sulc., which is related to the purple top and “zebra chip". Control alternatives have been inefficient because none of them has considered the spatial behavior of the insect inside the plot. Such behavior would allow us to focus the control alternatives in specific points. The purpose on this work was to model the spatial distribution of the eggs, nymphs and adults stages of B. cockerelli which were obtained in potato field by transects and quadrants sampling, using geostatistics and statistics tools that allow us to visualize their spatial distribution on the field through the creation of maps by kriging. The obtained results indicated that the dispersion index, the green index, Poisson and negative binomial of statistics showed inconsistency in determining the aggregation of the insect stadia detecting strong deficiencies and limitations, whereas the geostatistics techniques allowed to determine that the spatial distribution of eggs, nymphs and adult stages of B. cockerelli was aggregated in each of the three dates as in the sampling by transect as in the sampling by quadrants. Also, it was possible to model B.cockerelli spatial distribution in both methods. The crossed validation of the obtained semivariograms corroborates the aggregated distribution of eggs, nymphs and adults of B. cockerelli. The generated maps in the sampling by quadrants as by transects allowed to observe the aggregated structure of the insect population, which did not invade the potato plot in 100%, letting to identify the infested areas and the free areas of infestation. [ABSTRACT FROM AUTHOR]

Viral diseases are one of the most limiting factors in potato production. Recently, vein yellowing (VY) caused by PYVV has become one of the diseases with the highest incidence in potato crops in Colombia. In this work, symptoms commonly associated with viral infection were evaluated in potato crops from four provinces of Colombia, with emphasis in the vein yellowing disease. A correlation between VY, rugose mosaic (RM), leaf roll (LR) and dwarf (D) symptoms and the presence of potyvirus, PLRV, PVS and PVX was determined by ELISA. The presence of PYW was determined by RT-PCR. Incidence for each symptom was: RM (16%), LR (10%), VY (7%) and D (2%). The highest levels of VY (>20%) were observed in Eastern Antioquia and Ipiales (Nariño). There was not significant correlation between a symptom and a specific virus, since Potyvirus and PVS were found in 68% and 30% of samples, respectively. PYVV was detected in all samples with VY. However, at least another virus was found in 15% of these samples. [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Biotecnología is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of this work was to study the level of variation of PMTV isolates from Colombian potato crops through 2010 and 2011. Genes encoding for the viral coat protein (CP, ARN 2) and the Triple Gene Block (TGB2, ARN 3) were sequenced from PMTV isolates obtained in the provinces of Antioquia, Boyacá, Cundinamarca y Nariño. Additionally, RNA 2 and RNA 3 from two isolates were almost sequenced to completion (>83%). Phylogenetic analysis based on the CP sequence revealed the presences of two clades. The first clade included PMTV reference strains from all over the world and 19 Colombian isolates used in this study. The second class grouped only Colombian isolates and shared less than 76% identity with clade 1, suggesting a new pomovirus species. Complete genome sequencing is required to confirm this hypothesis. Phylogenetic analysis using the TGB2 gene grouped all sequences in a single clade. Sequence analysis of segments 2 and 3 of the viral genomes revealed >94% sequence identity with PMTV isolates from Czech Republic and Sweden. These findings will be helpful in the development of diagnostic tools for PMTV in the Andes in order to support tuber-seed certification and genetic improvement programs. [ABSTRACT FROM AUTHOR]

Copyright of BIOAGRO is the property of Revista BIOAGRO and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Colombiana de Biotecnología is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Colombiana de Biotecnología is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Facultad de Ciencias Basicas is the property of Revista Facultad de Ciencias Basicas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The potato (Solanum tuberosum L.) crop is strongly affected by different viruses that reduce yield and the quality of seed tubers. Knowledge of distribution and genetic variability of these pathogens is essential to support integrated pest management and breeding programs. In this research, the presence and molecular variability of PVX in potato crops was evaluated from the Colombian provinces of Antioquia, Cundinamarca, Boyacá and Nariño. The detection of this virus was performed by ELISA, while the variability was analyzed by sequencing a part of the viral capsid in 14 isolates as well as portions of genes codifying for proteins RdRp and Tgb1 for two isolates. Results indicated the presence of PVX in the four provinces with an average detection of 8%; although, in Nariño, PVX presence reached 15%. Molecular analysis indicated that most PVX Colombian isolates were associated with strains from Eurasia (Group I), while two isolates from Nariño grouped with Andean and some United Kingdom's strains (Group II). The information generated in this work will support programs of seed potato certification and breeding in Colombia. [ABSTRACT FROM AUTHOR]

This work was developed in order to determine the in vitro response of potato plants against the culture filtrate of Alternaria solani Sor. obtained in two culture media. To obtain filtrate culture were used CCIBP-VAs4 isolate and Fries and Richard culture m edia. The phytotoxicity of the filtrates was evaluated on in vitro plants susceptible (cv. 'Desirée') and resistant (the specie S. chacoense type Pi 275136) by immersion the roots of plants. The results showed that the filtrates obtained in both culture media were phytotoxic on both plant materials. However, culture filtrates that produced in Richard culture medium gave a better differentiation between potato plants cv. 'Desiree' (susceptible) and those of the wild species Solanum chacoense PI 275136 (resistant). This result was corresponded with the higher growth of the fungus in this culture medium. [ABSTRACT FROM AUTHOR]

Copyright of BIOAGRO is the property of Revista BIOAGRO and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Colombiana de Biotecnología is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Chapingo Serie Horticultura is the property of Universidad Autonoma Chapingo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Potato commercial yield reduction due to purple top syndrome in northeastern Mexico can reach up to 90% and sometimes losses can be total due to internal staining of the tubercles. A total of 214 genotypes were established during 2006 in Arteaga, Coah., Mexico, in order to evaluate and characterize their tolerance to the syndrome, and select those that had tolerance revealed as no vectors control were performed. The evaluated parameters were: height, foliage coverage, days to onset symptoms, days to plant death, onset of symptoms to death of the plant, total production of tubercles per plant, number of tubercles with internal staining per plant and sprouting of the plant, which were analyzed by multivariate statistical methods. The first three main components explained 76.8% of the total variance, separating first the producing genotypes from those non-producing; and second, the later with a higher coverage and lower thread outbreak from those with opposite characteristics. A total of three groups were identified by the cluster analysis: the first with 114 genotypes that did not produce tubercles, which had the symptoms revealed earlier and died. The second group, with 53 genotypes of greater tolerance, which had the highest average yield of tubercles per plant. The third with 47 genotypes, which had late manifestation of onset symptoms, had a wider range to wilt and a low production. The presence of bacteria, viruses and phytoplasm was detected in the tuber. The genotypes Gigant, Alpha, Norteña, Bayonera, Nieder, Atlantic and the clones 91-29-10, 98-14-01, 94-02-01 and 96-01-01 were selected based on their production or the absence of internal staining, even if the vectors were not controlled. [ABSTRACT FROM AUTHOR]

Copyright of Revista Facultad de Ciencias Basicas is the property of Revista Facultad de Ciencias Basicas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In Cuba are applied high amounts of Nitrogen on potato in relation with the average yields obtained. With the aim of define in representative soil-clime conditions the best amounts of Nitrogen for that crop and to prove if the actually recommended amounts decrease the yield because of favouring diseases, three trials were carried out under production conditions in two soils in the province of Villa Clara, Cuba (Typical Red Ferralític soil and Arenic Lixiviated Yellowish Ferralític soil). As control was used the Nitrogen amounts usually applied (220-230 kg ha-1) and lower amounts were tested (160-180-200 kg ha-1 in the first trial; 115-150-185 kg ha-1 in the second and 140-170-200 kg ha-1 in the third one). The Nitrogen was applied at a rate of 80 kg ha-1 as the formula 9 -- 13 -- 17 at plantation and the remainder amount, 30 days later, as formula plus urea. The potato sorts utilized were Chieftain, Romano and Red Scarlet. Each treatment consisted of 4 plots at random with 4 furrows of 340m long. The results showed that the N amounts usually applied under production conditions in Cuba are excessive even for high tuber yields for the country (30t ha-1), so that starting with relatively low amounts, the increasing application of the nutrient decrease the yield; that is associated to an increase of plant diseases such as Phytophthora infestans, Alternaria solani and Erwinia spp. Application of amounts according to the expected yields are recommended; those amounts do not shall surpass 180 kg ha-1 for yields until 30 tha-1. [ABSTRACT FROM AUTHOR]

This work presents a bibliographic review of the silver scurf disease and its causal agent Helminthosporium solani (Dur. & Mont.) in potatoes (Solanum tuberosum L.). The disease has a worldwide distribution and for at least 15 year it has acquired increasing importance as a limiting factor in the production of these tubers. The review shows the economic importance of the disease, its detection on tubers as well as in the soil, and its isolation procedures. It also explains the life cycle of H. solani, which is not completely known yet. It also discusses the possibilities for controlling silver scurf by the use of fungicides, tillage and cultivation methods in the field, storage management, the use of antagonists, and through the breeding of new cultivars. [ABSTRACT FROM AUTHOR]

El objetivo de este trabajo the identificar marcadores DNA Polimórfico Amplificado al Azar (RAPDs) y Secuencias Simples Repetidas (SSRs) también conocidos como Microsatélites asociados con la resistencia al daño causado por fitoplasmas en papa. Se evaluó la severidad de la punta morada de la papa (PMP) y la aparición de color pardo en el tubérculo, así como también se realizaron análisis moleculares en variedades y líneas avanzadas de papa. El estudio se realizó en el laboratorio de biotecnología de la Facultad de Ciencias Biológicas de la Universidad Autónoma de Nuevo León - Instituto Nacional de Investigaciones Forestales Agrícolas y Pecuarias (INIFAP), México en el 2003 y 2004. Las técnicas utilizadas fueron RAPDs y SSRs también conocido microsatélites. Tres genotipos mostraron resistencia a la aparición del color pardo del tubérculo, mientras que del análisis molecular seis materiales formaron un grupo que incluyó los genotipos con valores de daño mínimos (entre uno y tres de la escala). Los genotipos restantes formaron dos grupos con presencia de color pardo en el tubérculo mayor (entre cinco y siete). Se identificaron marcadores moleculares posiblemente asociados con tolerancia a la coloración parda del tubérculo. En el análisis de componentes principales y el dendograma generado los materiales que presentaron menor severidad de daño, quedaron incluidos en un mismo grupo, mientras que materiales con mayor severidad de daño quedaron en un grupo diferente. [ABSTRACT FROM AUTHOR]

Globally efforts have been made in the genetic improvement of potato by conventional methods. However, obtaining genotypes with good commercial quality and stable resistance to early blight has been difficult. Little resistance to early blight in commercial varieties has been the main reason that limits progress in genetic improvement. Sources of resistance to this disease have been identified in wild potato, but there are difficulties in the crossing with commercial varieties which have a high heterozygous polyploidy genome. Biotechnology tools, such as tissue culture, mutagenesis and in vitro selection, contribute to reduce these limitations. Besides, potato is a species which has been widely investigated by biotechnologists. The use of these techniques would enlarge the knowledge in plant-pathogen interaction in pathosystem potato-Alternaria solani. Also to obtain plants with resistance to early blight in a short period of time. The status of biotechnology application, in relation to the use of Alternaria solani culture filtrate in the selection of potato plants tolerant or resistant to early blight and how can be used as tools to improve this resistance to the disease, is described in this review. [ABSTRACT FROM AUTHOR]

Sampling for the presence of PVYN virus and its variant PVYNTN, as well as for weeds and insects associated with cultivation of potato (Solanum tuberosum), was carried out in fields intended for seed production in Tapalpa, State of Jalisco, Mexico. Forty one cultivars were analyzed, 19 from Tapalpa and 22 from Toluca, State of Mexico, by serological and molecular techniques. DAS-ELISA immunoassays revealed that cv. Malinche from Tapalpa was positive to PVYN, whereas a RT-PCR-based analysis identified the PVYNTN variant in Marinca from Toluca, as well as in Gigant, Malinche, and Alpha from Tapalpa. Among the different weed species associated to potato crop, Solanum nigrescens locally known as hierba mora, was found to be a natural reservoir for PVYN. The aphid Myzus persicae was identified to carry PVYNTN variant and it is considered as a probable vector. A 594 bp fragment, derived from samples that resulted positive for PVYNTN was amplified by RT-PCR, cloned and sequenced with 98% homology to an isolate from Canada, according to the sequence reported in the NCBI. These results confirmed the presence of the PVYNTN variant in commercial potato fields in Tapalpa, Jalisco, Mexico. [ABSTRACT FROM AUTHOR]

Bacterial contamination is one of the principal problems of plant tissue culture. The use of natural or synthetic antimicrobial substances represent an alternative for it solution. In potato micropropagation bacterial contamination produce serious damages. In this paper the effect of Gentamicine sulfate on control of high frequently contaminant was evaluated. The microorganism was isolated from media culture of potato cv. Desirée in vitro plants in multiplication stage. Traditional tintorial, bioquemical and physiological test were performed for bacteria identification together with BIOLOG bacteria identification system. Besides, the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of Gentamicine sulfate were determined and it antimicrobial and phytotoxic effect in multiplication stage were evaluated too. Pantoea agglomerans was identificated as potato contaminant and show sensibility to Gentamicine sulfate. The MIC was 0.625 mg·l-1 and the MBC was 1.25 mg·l-1. The antibiotics controlled the contamination in the 80% of contaminated explants without phytotoxicity at 2.5 mg·l-1. [ABSTRACT FROM AUTHOR]

The article offers information on the presence of golden nematode (PCN) Globodera rostochiensis in potato fields in Coahuila, Mexico. PCN Globodera rostochiensis is a disease affecting most potato growers in the world. PCN features encystment capacity as defense mechanism which make it harder to control. A study to identify the presence of PCN in Coahuila, Mexico was conducted. It is revealed that two out of twelve commercial plots sampled show PCN presence. The result of the study suggested the quarantine of only affected areas to avoid the spread of PCN.

The Toluca Valley in the central highlands of Mexico, has three peculiarities hardly coincident in other parts of the world for the natural development of the potato late blight disease: a) ideal climatic conditions for optimal onset of the oomycete every summer, b) the two mating types of the pathogen are usually close to a 1:1 ratio, consequently, a great deal of its progeny is sexually derived in the valley, inducing genetic variability of the microorganism, and c) there is a great diversity of wild Solanum species in the valley, being the main host genus for Phytophthora infestans, which establish a continuous host-pathogen relationship in a biological equilibrium leading to natural co-evolution. These factors support the importance of the valley to study the microorganism, and the relationship with its hosts. [ABSTRACT FROM AUTHOR]

A sampling plan was designed, starting from the results about the distribution in plant and field of T. palmi potato crop. For this, two sampling proceedings were considered in productive areas of Havana province during three years. They consisted on evaluating larvae density in parcels or in the diagonal of the sector. Mean density was valued by means of variance analysis and means were compared by Duncan (p< 0.05). Relative variation , net relative precision and the most adequate sample size were also calculated. The results showed that, starting from means superior to 3.01 larvae/ folioles, the best procedure is in diagonal, while at lower values, the best estimation was achieved in parcels. In this case the sample required approached at 100 folioles. In a way that population increases 50 and 64 folioles, a reliable sample size can be obtained. [ABSTRACT FROM AUTHOR]

Potato soft rot is the bacterial disease of this crop which happens more frequently in Cuba causing economic losses. In this paper, the in vitro antagonist effect of different Bacillus strains against Pectobacterium carotovorum, Pectobacterium atrosepticum and Dickeya chrysanthemi was estudied using diffusion in agar method. Except B9, all the strains had inhibitory effect on the growth of all the phyopathogenic bacteria analyzed. B1 and B2 strains showed the best antagonist effects, being achieved in both cases inhibition halos of considerable size. The results suggest that some of these strains could be considered as potential agents of biological control of the soft rot. [ABSTRACT FROM AUTHOR]