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Antixenosis to the Peach-potato Aphid, Myzus persicae (Sulzer) in Potato Cultivars  [PDF]
A.U.R. Saljoqi,H.F. van Emden,He Yu-rong
Asian Journal of Plant Sciences , 2003,
Abstract: Field studies were conducted to determine the antixenotic resistance against the peach-potato aphid, Myzus persicae (Sulzer) in different potato cultivars i.e. Cardinal, Ultimus and Desiree. These cultivars were studied in the paired tests as Cardinal vs. Desiree and Cardinal vs. Desiree for antixenosis (systemic insecticide-based test). In Desiree vs. Ultimus, no significant difference was found for the preference of M. persicae, while in case of Cardinal vs. Desiree, there was a significant preference for Desiree. Cardinal clearly showed antixenosis to M. persicae.
Single nucleotide polymorphism discovery in elite north american potato germplasm
John P Hamilton, Candice N Hansey, Brett R Whitty, Kevin Stoffel, Alicia N Massa, Allen Van Deynze, Walter S De Jong, David S Douches, C Robin Buell
BMC Genomics , 2011, DOI: 10.1186/1471-2164-12-302
Abstract: To identify a large number of Single Nucleotide Polymorphisms (SNPs) in elite potato germplasm, we sequenced normalized cDNA prepared from three commercial potato cultivars: 'Atlantic', 'Premier Russet' and 'Snowden'. For each cultivar, we generated 2 Gb of sequence which was assembled into a representative transcriptome of ~28-29 Mb for each cultivar. Using the Maq SNP filter that filters read depth, density, and quality, 575,340 SNPs were identified within these three cultivars. In parallel, 2,358 SNPs were identified within existing Sanger sequences for three additional cultivars, 'Bintje', 'Kennebec', and 'Shepody'. Using a stringent set of filters in conjunction with the potato reference genome, we identified 69,011 high confidence SNPs from these six cultivars for use in genotyping with the Infinium platform. Ninety-six of these SNPs were used with a BeadXpress assay to assess allelic diversity in a germplasm panel of 248 lines; 82 of the SNPs proved sufficiently informative for subsequent analyses. Within diverse North American germplasm, the chip processing market class was most distinct, clearly separated from all other market classes. The round white and russet market classes both include fresh market and processing cultivars. Nevertheless, the russet and round white market classes are more distant from each other than processing are from fresh market types within these two groups.The genotype data generated in this study, albeit limited in number, has revealed distinct relationships among the market classes of potato. The SNPs identified in this study will enable high-throughput genotyping of germplasm and populations, which in turn will enable more efficient marker-assisted breeding efforts in potato.The most widely cultivated potato species, Solanum tuberosum Group Tuberosum, is an autotetraploid (2n = 4x = 48) and the world's third most important food crop in overall production, after rice and wheat [1]. Potato improvement is constrained by numerous ch
Management of Aphid (Myzus persicae) on Autumn Sown Potato Crop  [PDF]
Muhammad Tahir Jan,Muhammad Idrees Khan,Rashid Mahmood,Muhammad Naeem
Asian Journal of Plant Sciences , 2002,
Abstract: For aphid management, mix cropping (PBM and PRM), four insecticides(DDVP, Anthio, Monitor and Laser) and yellow plastic sheet trap were used. The incidence of the pest was recorded on the leaves of the potato plants and yellow plastic sheets. The emergence of the pest on the crop occurred during October, which increased to the peak 43 aphids /leaf in the month of December. However on yellow plastic sheets, alate form of the aphids were recorded during the third week of September, which remain in abundance from the fourth week of November to the third week of December with the highest count 235 aphids /trap during second week of December. Among the treatments YPT, PBM and Monitor were found most effective against aphids during the entire growing season. Maximum reduction (72%), in YPT, (70%) in PBM and (52%) in the plot reserved for Monitor, in the aphid population was recorded. In the remaining treatments 40-50% of the population was reduced during the intact growing season of the potato crop when compared with control.
Influence of Abiotic Environment on the Population Dynamics of Mustard Aphid, Lipaphis Erysimi (Kalt.) On Brassica Germplasm
M.S. Ansari,Barkat Hussain,N.A. Qazi
Journal of Biological Sciences , 2007,
Abstract: The natural appearance of mustard aphid on Brassica germplasm was observed on 11th January (60 DAS) and disappeared after 2nd March (110 DAS). The peak aphid population was found at a maximum, minimum and average temperature of 23.37°, 6.87° and 15.76°C, respectively and mean relative humidity of 54.75% on 10th February at 90 DAS. Then, decline in aphid population and simultaneously increase of Coccinella was at 100 and 110 DAS, respectively. Maximum and average temperature showed as positively non-significant effect while minimum temperature caused negatively non-significant on the population of aphid. However, relative humidity had a negative effect. Late appearance of Coccinella too could not have any regulatory effect on the incidence of this pest.
Screening of exotic potato germplasm for resistance to stem necrosis  [cached]
Indian Phytopathology , 2012,
Abstract: Stem necrosis caused by a Groundnut bud necrosis virus is a serious disease of potato in central India. In order to find sources of resistance to this disease, 207 exotic accessions of cultivated potato were screened under natural conditions in fields at Gwalior for three successive years. A large number of accessions(33.8%) were found to be resistant to highly resistant. These can be used in potato breeding programme for developing varieties adopted to the region and having resistance to stem necrosis.
Incidence of Aphid-Transmitted Viruses in Farmer-Based Seed Potato Production in Kenya  [PDF]
J.W. Muthomi,J.N. Nyaga,F.M. Olubayo,J.H. Nderitu
Asian Journal of Plant Sciences , 2009,
Abstract: Field studies were carried out in farmer-based seed potato production to determine the incidence of potato aphids and potato aphid-transmitted viruses in two potato-producing areas of Kenya. Parameters determined included aphid population, virus disease incidence and tuber yield. Aphid population was monitored on leaves and in water-pan traps. Virus infection was determined based on symptoms and the viruses were identified in tubers sprouts by DAS-ELISA. Tuber yield was determined for plants showing virus symptoms and healthy-looking plants. Five aphid species were identified, with the most abundant being M. euphorbiae and A. gossypii on leaves and M. persicae and A. gossypii in water traps. The average aphid population was between 1.4 and 4.2 aphids per three leaves and 4.68 and 9.64 aphids per water pan trap. Farms with higher population of M. persicae had higher virus disease incidence. The most prevalent viruses were PVS, PLRV and PVM. Healthy looking plants had a latent infection rate 57.2% compared to 76.6% for symptomatic plants. Virus infection reduced the number and weight of tubers by 74 and 62.7%, respectively. However, virus infection increased the number and weight of the chats grade. The results indicated that aphid infestation and virus disease incidence were higher than the recommended for seed potato production. Therefore, there is need to create awareness among the farmers on aphid and virus symptom recognition and use of clean certified seed potato.
Antibiosis and antixenosis of six commonly produced potato cultivars to the green peach aphid, Myzus persicae Sulzer (Hemiptera: Aphididae)
Mottaghinia, L;Razmjou, J;Nouri-Ganbalani, G;Rafiee-Dastjerdi, H;
Neotropical Entomology , 2011, DOI: 10.1590/S1519-566X2011000300012
Abstract: the antibiotic and antixenotic resistance of six commonly produced potato cultivars in iran including aozonia, agria, cosima, cosmos, kondor and savalan to the green peach aphid, myzus persicae sulzer, were investigated under laboratory conditions at 20 ± 2oc, 65 ± 5% rh and 16:8h (l:d) in 2009. antibiosis experiments showed significant differences in the developmental time, nymphal survivorship, fecundity, adult longevity of the green peach aphid among the potato cultivars. intrinsic rate of natural increase (rm) for apterous aphids varied significantly with the potato cultivars on which the aphids were reared. this value ranged from 0.225 to 0.293 females/female/day, which was lowest on cosmos and highest on aozonia. additionally, the estimated net reproductive rate (r0) and finite rate of increase (λ) for apterous aphids were the lowest on cosmos. for the antixenosis experiment, no significant difference was found in aphid's preference to the potato cultivars. however, aozonia was preferred more than the other five cultivars by the apterous aphids. therefore, our results demonstrated that among the investigated cultivars the cosmos cultivar is moderately resistant to the green peach aphid.
Potential Use of Insecticides and Mineral Oils for the Control of Transmission of Major Aphid-Transmitted Potato Viruses
Drago Milo?evi?,Svetomir Stamenkovi?,Pantelija Peri?
Pesticidi i Fitomedicina , 2012,
Abstract: Viruses occurring in Serbia and other countries in the region are a huge problem constrainingseed potato production. At lower altitudes, in lowland and hilly regions, wheretable potato production is widely distributed, more than 50% of healthy plants becomeinfected with potato virus Y during one growing season. Under these conditions, seed potatoproduction is hindered due to a high infection pressure of potato virus Y which spreads farmore rapidly compared to leaf roll virus, virus S and other viruses hosted by this plant species.This study tended to clarify a frequent dilemma regarding the use of insecticides in preventingthe infection of healthy plants with potato virus Y and leaf roll virus, given the oraland written recommendations from pesticide manufacturers, agronomists and scientistsin the field of crop protection arising from a logical conclusion that aphid vector controlresults in virus transmission control.The present findings, which are in agreement with reports of authors from other countries,show that the use of insecticides is ineffective in preventing potato virus Y which isnonpersistently transmitted by aphids from an external source of infection.However, insecticides can exhibit efficacy in preventing potato virus Y transmissionfrom infected plants to healthy plants within a crop, which can have an overall positiveeffect only if seed potato is grown in areas that have no external source of infection.The present results and those of other authors show that insecticides are effective inpreventing the infection of healthy plants with persistently transmitted leaf roll virus.Mineral oils provide effective control of potato virus Y by preventing the infection ofpotato plants with the virus. They can be combined with other management practices toprotect seed potato crops against the virus.Given the fact that the initial first-year infection of healthy potato plants with virus Y inrelation to leaf roll virus is approximately 10-20:1 under conditions in Serbia, and that the useof insecticides fails to ensure protection against PVY, this practice cannot have any positiveeffect on virus control under high infection pressure conditions.
Tracking the global dispersal of a cosmopolitan insect pest, the peach potato aphid
John T Margaritopoulos, Louise Kasprowicz, Gaynor L Malloch, Brian Fenton
BMC Ecology , 2009, DOI: 10.1186/1472-6785-9-13
Abstract: Bayesian clustering and admixture analysis split the aphid genotypes into three genetic clusters: European M. persicae persicae, New Zealand M. persicae persicae and Global M. persicae nicotianae. This partition was supported by FST and genetic distance analyses. The results showed two further points, a possible connection between genotypes found in the UK and New Zealand and globalization of nicotianae associated with colonisation of regions where tobacco is not cultivated. In addition, we report the presence of geographically widespread clones and for the first time the presence of a nicotianae genotype in the Old and New World. Lastly, heterozygote deficiency was detected in some sexual and asexual populations.The study revealed important genetic variation among the aphid populations we examined and this was partitioned according to region and host-plant. Clonal selection and gene flow between sexual and asexual lineages are important factors shaping the genetic structure of the aphid populations. In addition, the results reflected the globalization of two subspecies of M. persicae with successful clones being spread at various scales throughout the world. A subspecies appears to result from direct selection on tobacco plants. This information highlights the ultimate ability of a polyphagous aphid species to generate and maintain ecologically successful gene combinations through clonal propagation and the role of human transportation and global commerce for expanding their range.Myzus persicae (Sulzer) (Hemiptera: Aphididae) is an exceptional species in many respects. It is extremely polyphagous, highly efficient as a plant-virus vector and one of the most widespread insect pests, as it has been recorded on all continents where crops are grown [1]. The species has a typical aphid annual cycle (cyclical parthenogenesis), i.e., a sexual generation on peach during winter and spring, alternating with many parthenogenetic (all female) generations during spring on peac
Eternal Bengal Eternal Bengal  [cached]
Ranabir Samaddar
Scienza & Politica : per una Storia delle Dottrine , 2011, DOI: 10.6092/issn.1825-9618/2715
Abstract: Eternal Bengal
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