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  Subjects -> AGRICULTURE (Total: 653 journals)
    - AGRICULTURAL ECONOMICS (70 journals)
    - AGRICULTURE (438 journals)
    - CROP PRODUCTION AND SOIL (84 journals)
    - DAIRYING AND DAIRY PRODUCTS (24 journals)
    - POULTRY AND LIVESTOCK (37 journals)

AGRICULTURE (438 journals)                  1 2 3 4 5 | Last

Acta agriculturae Slovenica     Open Access   (4 followers)
Acta Agrobotanica     Open Access   (2 followers)
Acta Agronomica Hungarica     Full-text available via subscription   (1 follower)
Acta Agronomica Sinica     Full-text available via subscription   (6 followers)
Acta Scientiarum. Animal Sciences     Open Access  
Acta Scientiarum. Technology     Open Access  
Acta Technologica Agriculturae     Open Access  
Advances in Agriculture & Botanics     Open Access   (10 followers)
Advances in Agriculture, Sciences and Engineering Research     Open Access   (10 followers)
Advances in Agronomy     Full-text available via subscription   (12 followers)
Advances in Life Science and Technology     Open Access   (4 followers)
AFBM Journal     Open Access  
Africa Development     Open Access   (2 followers)
Africa Research Bulletin: Political, Social and Cultural Series     Hybrid Journal   (6 followers)
African Journal of Agricultural Research     Open Access  
African Journal of Food Science     Open Access   (1 follower)
African Journal of Food, Agriculture, Nutrition and Development     Open Access  
African Journal of Horticultural Science     Open Access   (2 followers)
African Journal of Range and Forage Science     Hybrid Journal   (5 followers)
African Journal of Sustainable Development     Full-text available via subscription   (2 followers)
Agribusiness : an International Journal     Hybrid Journal   (5 followers)
Agricultura Tecnica     Open Access   (5 followers)
Agricultura Tropica et Subtropica     Open Access   (1 follower)
Agricultural Advances     Open Access   (3 followers)
Agricultural and Food Science     Open Access   (14 followers)
Agricultural Economics     Hybrid Journal   (43 followers)
Agricultural History     Full-text available via subscription   (96 followers)
Agricultural Research     Hybrid Journal   (2 followers)
Agricultural Science     Full-text available via subscription   (5 followers)
Agricultural Sciences     Open Access   (7 followers)
Agricultural Sciences in China     Full-text available via subscription   (3 followers)
Agricultural Systems     Hybrid Journal   (19 followers)
Agricultural Water Management     Hybrid Journal   (13 followers)
Agriculture     Open Access   (4 followers)
Agriculture & Food Security     Open Access   (7 followers)
Agriculture (Poľnohospodárstvo)     Open Access   (1 follower)
Agriculture and Agricultural Science Procedia     Full-text available via subscription  
Agriculture and Human Values     Hybrid Journal   (10 followers)
Agriculture, Ecosystems & Environment     Hybrid Journal   (29 followers)
Agriprobe     Full-text available via subscription  
Agrivita : Journal of Agricultural Science     Open Access   (4 followers)
Agro-Science     Full-text available via subscription  
Agroalimentaria     Open Access   (1 follower)
Agrociencia     Open Access   (2 followers)
Agrokémia és Talajtan     Full-text available via subscription   (2 followers)
Agronomía Colombiana     Open Access   (1 follower)
Agronomía Costarricense     Open Access   (2 followers)
Agronomía Mesoamericana     Open Access   (1 follower)
Agronomie Africaine     Full-text available via subscription  
Agronomy     Open Access   (8 followers)
Agrosearch     Open Access  
AI & Society     Hybrid Journal   (2 followers)
Alinteri Zirai Bilimler Dergisi : Alinteri Journal of Agricultural Sciences     Open Access  
Ambiência     Open Access  
Ambiente & Agua : An Interdisciplinary Journal of Applied Science     Open Access   (1 follower)
American Journal of Agricultural and Biological Sciences     Open Access   (9 followers)
American Journal of Botany     Full-text available via subscription   (13 followers)
American Journal of Economics and Sociology     Hybrid Journal   (18 followers)
American Journal of Potato Research     Hybrid Journal   (2 followers)
Anais da Academia Brasileira de Ciências     Open Access   (2 followers)
Annales UMCS, Agricultura     Open Access  
Annales UMCS, Horticultura     Full-text available via subscription  
Annals of Agricultural and Environmental Medicine     Open Access   (1 follower)
Annals of Agricultural Sciences     Open Access   (1 follower)
Annual Review of Resource Economics     Full-text available via subscription   (10 followers)
APCBEE Procedia     Partially Free   (2 followers)
Applied Economics Letters     Hybrid Journal   (18 followers)
Applied Financial Economics Letters     Hybrid Journal   (4 followers)
Arboricultural Journal : The International Journal of Urban Forestry     Hybrid Journal   (5 followers)
Archivos de Zootecnia     Open Access  
Arquivos do Instituto Biológico     Open Access  
Arthropod-Plant Interactions     Hybrid Journal   (1 follower)
Asian Economic Papers     Hybrid Journal   (3 followers)
Asian Journal of Agricultural Research     Open Access   (2 followers)
Asian Journal of Plant Sciences     Open Access   (1 follower)
Australian Cottongrower, The     Full-text available via subscription   (1 follower)
Australian Economic Papers     Hybrid Journal   (5 followers)
Australian Forest Grower     Full-text available via subscription   (2 followers)
Australian Forestry     Full-text available via subscription   (4 followers)
Australian Grain     Full-text available via subscription   (4 followers)
Australian Holstein Journal     Full-text available via subscription  
Australian Journal of Agricultural and Resource Economics     Hybrid Journal   (5 followers)
Australian Journal of Agricultural Engineering     Open Access  
Australian Sugarcane     Full-text available via subscription  
Avances en Investigacion Agropecuaria     Open Access  
Bangladesh Journal of Agricultural Research     Open Access   (1 follower)
Bangladesh Journal of Scientific Research     Open Access  
Berkala Ilmiah Pertanian     Open Access   (1 follower)
Bioagro     Open Access   (1 follower)
Biocatalysis and Agricultural Biotechnology     Hybrid Journal   (5 followers)
Biocontrol Science and Technology     Hybrid Journal   (5 followers)
Biodiversity     Hybrid Journal   (16 followers)
Biodiversity : Research and Conservation     Open Access   (17 followers)
Biological Agriculture & Horticulture : An International Journal for Sustainable Production Systems     Partially Free   (12 followers)
Biosystems Engineering     Hybrid Journal   (1 follower)
Biotemas     Open Access  
Bragantia     Open Access   (2 followers)
Brazilian Archives of Biology and Technology     Open Access   (1 follower)
British Poultry Science     Hybrid Journal   (5 followers)
California Agriculture     Open Access   (1 follower)

        1 2 3 4 5 | Last

American Journal of Potato Research    [4 followers]  Follow    
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1874-9380 - ISSN (Online) 1099-209X
     Published by Springer-Verlag Homepage  [2187 journals]   [SJR: 0.639]   [H-I: 26]
  • Management Effects of Disease-Suppressive Rotation Crops on Potato Yield
           and Soilborne Disease and Their Economic Implications in Potato Production
           
    • Abstract: Abstract Soilborne potato diseases are persistent problems in potato production. Use of disease-suppressive rotation crops, such as Brassica spp. (mustards, rapeseed) and sudangrass, has shown potential for management of soilborne diseases and enhanced yield in various crop production systems. However, how to best implement these crops into productive potato cropping systems has not yet been determined. In this research, potential disease-suppressive crops were evaluated under four different types of production management (as a cover crop, green manure, harvested crop-residue incorporated, and harvested crop-residue not incorporated) in potato rotation field trials, and their effects on disease, yield, and economic viability determined. Mustard blend, sudangrass, and rapeseed rotations reduced the tuber disease black scurf (by 16–27 %) and increased yield (by 6–11 %) relative to a barley rotation control, but only mustard blend consistently reduced common scab (by 11 %). All rotation crops managed as green manures produced lower disease (by 15–26 %) and higher yields (by 6–13 %) than other management practices. Overall, the combination of mustard blend managed as a green manure was most effective, reducing scurf by 54 % and increasing yield by 25 % relative to a soybean cover crop. The use of mustard or rapeseed as a harvested crop with incorporation provided the best economic return, increasing net income by more than $860/ha relative to the standard barley rotation, but mustard blend grown as a green manure or non-incorporated harvest crop also substantially increased net income ($600 to $780/ha).
      PubDate: 2014-01-24
       
  • The Pathosystem Solanum
           tuberosum
    L.-       class="a-plus-plus">Phytophthora infestans (Mont.)
           de Bary in Chapingo, Mexico. Expected, Observed, and Simulated
    • Abstract: Abstract The 1:1 ratio of the Phytophthora infestans A1 and A2 mating types favors the sexually derived genetic diversity of the late blight pathogen of potatoes, which is widespread in the central highlands of México. This ratio guarantees the successful infection of this pathogen, even in resistant potato hosts. However, wild Solanum species present in the region serve as alternative hosts to the pathogen. Knowledge about the external factors that influence the dynamics of this disease facilitates the assessment and selection for genetically resistant potato cultivars to late blight, in addition to providing the capacity to predict epidemics. This work aimed to assess the expected, observed, and simulated progress of natural P. infestans infection of potatoes during two epiphytotic field seasons (2009 and 2010) at Chapingo, México. Using 8-years of weather datasets, six ideal situations were predicted with four to eight infection cycles of 6 to 12 h each. In comparison to the predictions, the observed effect of the area under the disease progress curve, and its components (AUDPC, RAUDPC, RaRAUDPC), was highly significant, with a low coefficient of variation among the potato cultivars used in the study. In conclusion, we confirm that the LATEBLIGHT-LB2004 model is useful for simulating and predicting late blight epidemics based on the weather conditions of Chapingo, except for the magnitude of the relative humidity threshold variable (RH_threshold), which requires calibration for each cultivar.
      PubDate: 2014-01-24
       
  • Stability Analysis of Agronomic Traits in Potato Cultivars of Different
           Origin
    • Abstract: Abstract Potato (Solanum tuberosum ssp. tuberosum) cultivars are expected to express a stable level for traits important for growers and consumers. To investigate how this expectation was met by a set of 21 cultivars bred in Hungary, Poland and Spain, 2-year field experiments were carried out in these countries for the evaluation of tuber yield, starch content and yield, and occurrence of secondary growth of tubers. Stability in an agronomic sense was evaluated by the analysis of genotype by environment interaction (GE) using the Scheffé-Caliński mixed model. Unstable trait expression was indicated by the statistically significant share of GE in the variability contributed by a specific cultivar. This instability could lead to either complete or partial unpredictability. Stable trait expression was observed for 6–11 cultivars, depending on the trait. A significant genetic factor, which indicates broad adaptation, was rarely found. Stable expression of tuber yield occurred together with stable or predictable expression of both starch content and yield. Unstable expressions of tuber and starch yield were also associated. The stability or instability of secondary growth was not associated with stability or instability of the other measured traits. Analysis of GE interaction was useful for identifying stable or unstable responses and revealed the presence of incomplete stability or partial unpredictability as intermediate types of reaction.
      PubDate: 2014-01-18
       
  • Modification of ELISA by Replacing Incubation of Microtiter Plates in an
           Incubator with Their Shaking in PVY, PVM and PLRV Detection
    • Abstract: Abstract ELISA (enzyme-linked immunosorbent assay) is a sensitive and reliable method of plant virus detection. It is commonly used in daily research carried out by scientific institutions and laboratories working on the certification of potato tubers. The key stage in this method is a 3–4-h-long incubation of microtiter plates with IgG and with a conjugate in an incubator at a temperature of 37 °C. The aim of the research was to replace this type of incubation process with a technique of mechanically shaking the plates using a shaker to induce a vibrating movement. Three durations of shaking, performed at room temperature, were adopted: 30, 60 and 90 min with two incubation periods at a temperature of 37 °C: 60 and 180 min which were applied at the stage of coating the IgG plates, following addition of the conjugate. The assessment was made for three dilutions of lyophilized sap from leaf of potatoes (1:10, 1:100, 1:1,000). Replacing the stages of plates incubation with IgG and conjugate at 37 °C with mechanical shaking allowed the whole process of DAS-ELISA to be reduced below 3–4 h without any significant impact on its quality. The process turned out to be equally efficient as the 3-h-long incubation in an incubator for PVY, PVM and PLRV detection by means of DAS ELISA. Applying the 90-min-long incubation on a shaker in comparison to a 3-h-long incubation in an incubator gave comparable or even slightly improved results. The reaction background, i.e. the value of absorbance for sap from healthy plants (negative control) was very low in all the combinations irrespective of the time of reading after the substrate was placed. No significant differences for this parameter were found between the combinations and times of reading. Only in the case of PLRV was a clearly visible decrease in test sensitivity found (no positive reactions) at diluted sap over 1:10. Moreover, it was observed that an increase in dilutions impacted the length of reaction. The dilution 1:10 seemed to be the most favorable (maximum 1:100 for PVY and PVM), wherein the sensitivity and pace of staining the substrate for each of the methods did not provoke any doubts regarding the reliability of the test.
      PubDate: 2014-01-18
       
  • The Potato Association of America 97       class="a-plus-plus">th Annual Meeting
    • PubDate: 2014-01-03
       
  • Glyphosate Carryover in Seed Potato: Effects on Mother Crop and Daughter
           Tubers
    • Abstract: Abstract Field studies were conducted in 2008 and 2009 in Aberdeen, ID, Ontario, OR, and Paterson, WA to determine the effect of simulated glyphosate drift on ‘Ranger Russet’ potato during the application year and the crop growing the next year from the daughter tubers. Glyphosate was applied at 8.5, 54, 107, 215, and 423 g ae ha−1 which corresponds to 1/00, 1/16, 1/8, ¼, and 1/2 of the lowest recommended single-application rate for glyphosate-resistant corn and sugar beet of 846 g ha–1. Glyphosate was applied when potato plants were at 10 to 15 cm tall (Early), or at stolon hooking (H), tuber initiation (TI), or during mid-bulking (MB). In general, the MB applications caused less visual foliar injury to the mother crop than earlier applications at ID or OR, and H applications at WA. Mother crop injury increased as glyphosate rate increased regardless of location, application timing, and rating date. U.S. No.1 and total tuber yields were usually related to the injury level resulting from glyphosate application timings and rates. Although injury to the mother crop from glyphosate applied at MB usually was the lowest compared to injury from other application timings, when daughter tubers from that timing were planted the following year, emergence, plant vigor, and yield was most detrimentally impacted compared with that of daughter tubers from other timing treatments. MB daughter tuber emergence was less than 30 % of the nontreated control tuber emergence while emergence of daughter tubers from the other treatments was 60 to 95 %. As rate of glyphosate applied to the mother crop increased, daughter tuber emergence decreased. When MB daughter tubers did emerge, plants were chlorotic and stunted as if the plants had been directly sprayed with glyphosate. Regardless of whether the daughter tubers had defects or not, results the following year were the same. Implications are that if a mother seed crop encounters glyphosate during bulking, injury may not even be noticeable on the foliage or the tubers, however, emergence, vigor, and yield of the crop growing the following year from the daughter tubers could be greatly impacted.
      PubDate: 2014-01-01
       
  • Teton Russet: An Early-Maturing, Dual-Purpose Potato Cultivar Having
           Higher Protein and Vitamin C Content, Low Asparagine, and Resistances to
           Common Scab and        class="a-plus-plus">Fusarium Dry Rot
    • Abstract: Abstract Teton Russet is an early-maturing, medium-russeted, potato cultivar with high merit for both fresh-pack and processing. In early harvest trials in the Pacific Northwest, Teton Russet had total yields similar to Russet Norkotah, and higher than Ranger Russet and Russet Burbank. Marketable yield of Teton Russet in the early harvest trials was also comparable to or higher than Russet Norkotah in Washington and Oregon, and higher than Ranger Russet and Russet Burbank at these sites, as well as in Idaho. In full-season trials, while total yield of the earlier-maturing Teton Russet tended to be lower than Ranger Russet and Russet Burbank, marketable yield was generally higher than Russet Burbank across the majority of sites due to its higher percentage of U.S. No. 1 tubers. Teton Russet is suitable for processing, with acceptable fry color following up to 8 months of storage at 8.9 °C. Uniformity of fry color was also very consistent. Teton Russet has shown lower levels of the amino acid asparagine relative to Ranger Russet and Russet Burbank which may contribute to lower acrylamide levels in French fries and other processed potato products. Teton Russet is notable for having resistance to common scab (Streptomyces spp.) and Fusarium dry rot, and is moderately resistant to tuber net necrosis. Analyses have also shown Teton Russet to have significantly higher protein levels than Russet Norkotah, Ranger Russet, and Russet Burbank, as well as higher vitamin C content than Russet Norkotah and Russet Burbank. Teton Russet was released in 2011 by the USDA-ARS and the Agricultural Experiment Stations of Idaho, Oregon, and Washington, and is a product of the Pacific Northwest Potato Variety (Tri-State) Development Program.
      PubDate: 2013-12-20
       
  • Selection and Validation of an AFLP Marker Core Collection for the Wild
           Potato Solanum
           microdontum
    • Abstract: Abstract Solanum microdontum is a diploid potato species with features that make it a good model for research into management and use of germplasm in the genebank. Its taxonomic status is unambiguous and it is in the taxonomic series of wild species closest to cultivated forms. It is represented by about 100 populations in the genebank—not too many for comprehensive evaluation, yet not too few to make prioritization of the most valuable populations worthwhile. This species is also particularly rich in desirable traits, often exhibiting very broad segregation. We here report use of DNA markers for selection of a core set of populations, and assessing whether that core captures populations with the most desirable evaluation results for economic traits. DNA was extracted from bulks of 27 plants from each of 94 populations to generate AFLPs. A total of 1,741 informative loci were detected. AFLP loci were treated as though they were traits, with the banded condition considered to be the desired state to include in a core set. At least one band unique to a population was present in 45 populations, and these 45 populations together captured 98 % of all bands. Adding another 14 populations for a core of 59 populations captured 100 % of bands. This core set was assessed for whether it encompassed those populations known to have useful traits, including nutritional and quality components; and disease, stress and pest resistances. As with AFLP bands, 25 of 26 of the most desirable phenotypic traits were also found in populations in the core set of 59 populations. The most desirable status of 3 traits is lost by selecting a core of 45 populations. We conclude that these core sets would be a rational starting point when prospecting for new useful traits in microdontum.
      PubDate: 2013-12-20
       
  • Abstracts of the Papers Presented at the 97       class="a-plus-plus">th Annual Meeting of The
           Potato Association of America
    • PubDate: 2013-12-13
       
  • Resistance of Selected Potato Genotypes to the Potato Psyllid (Hemiptera:
           Triozidae)
    • Abstract: Abstract The characterization of resistance of selected potato, Solanum tuberosum L., breeding clones to the potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae) was investigated. Antixenosis was assessed in choice tests in which a single plant of each genotype was placed inside a rearing cage, where 60 female psyllid adults were released and the number of adults and eggs on each genotype was counted 24 h later. Antibiosis was evaluated in no-choice tests in which adults (five males and five females) were confined in a cage fixed to the upper side of leaves. After 4 h of exposure, adults were removed and the number of eggs counted. The developmental time and survival of offspring were recorded until all insects became adults. All the resistant genotypes showed strong antibiotic effects to B. cockerelli. These results show promise for incorporation into an IPM program against B. cockerelli.
      PubDate: 2013-12-13
       
  • The Potato Association of America Honorary Life Members, 2013
    • PubDate: 2013-12-06
       
  • Varietal Differences in Minituber Production Costs
    • Abstract: Abstract Minitubers have become important components of seed potato production systems. Minituber production methods and yields affect costs. We used data from the University of Wisconsin seed potato program to estimate minituber production costs by variety in 2009, 2010, and 2011. Labor is identified as the most significant operating cost, while salaries represent the greatest fixed cost. The 3 year average total cost per minituber across all varieties was estimated at $0.47. Of the varieties grown in all 3 years of analysis Langlade had the highest average yield and lowest cost. Yukon Gold and Pike had the lowest yields and highest costs.
      PubDate: 2013-12-06
       
  • Benchmarking Food Crop Markets in Southern Africa: The Case of Potatoes
           and Potato Products 1961–2010
    • Abstract: Abstract Pressures and opportunities in food systems across Southern Africa have generated renewed interest in potatoes both as a food crop and a source of income in recent years. With populations growing at over 2.0 %/year in several countries and urban consumers often eager to diversify their diets, new markets are also opening up. Given these trends, growers, traders and governments are seeking out new ways to capitalize on these developments. This paper examines the evolution of growth rates in potato production, utilization and trade in Southern Africa over nearly the last half century using FAO annual secondary data. After highlighting the different roles that potatoes have played in crop diversification across the sub-region, the paper identifies some key issues for future research as well as some opportunities for industry both large and small.
      PubDate: 2013-12-01
       
  • Effects of Soil Flooding on the Survival of Two Potato Pathogens,        class="a-plus-plus">Sclerotinia sclerotiorum and
           Verticillium dahliae
    • Abstract: Abstract Results of studies on survival of sclerotia of Sclerotinia and microsclerotia of Verticillium, demonstrated that soil flooding in western Washington is a possible alternative field rotation practice for S. sclerotiorum (white mold), but not for V. dahliae (Verticillium wilt). Cone-tainer experiments in the greenhouse showed that flooding at 16.5 °C caused S. sclerotiorium sclerotia to lose viability between 12 and 24 weeks while a growth chamber experiment revealed that flooding for 18 weeks at 11 °C or 20 °C was sufficient. V. dahliae microsclerotia appeared resistant to flooding under greenhouse and field settings; recovery ranged within 5 to 10 % of the initial soil population after 6 and 12 months. Potatoes planted into field microplots either flooded or fallowed the previous summer had similar Verticillium wilt ratings and potato yield. Lack of control of V. dahliae by flooding may be due partly to relatively low soil temperatures in a cool, marine climate.
      PubDate: 2013-12-01
       
  • Haplotypes of the Potato Psyllid,        class="a-plus-plus">Bactericera cockerelli, on the
           Wild Host Plant, Solanum
           dulcamara
    , in the Pacific Northwestern United States
    • Abstract: Abstract ‘Candidatus Liberibacter solanacearum’ (Lso) is a bacterium that infects solanaceous crops and causes plant decline and yield losses, especially in potato and tomato. Lso is transmitted to these hosts by the potato psyllid (Bactericera cockerelli Sulc) vector. B. cockerelli host plants are not limited to crop plants, but also include many wild, solanaceous weeds. These wild hosts could potentially impact overwintering and breeding of the psyllids and serve as reservoirs for Lso. In the Pacific Northwestern United States, B. cockerelli was recently reported to overwinter on bittersweet nightshade (Solanum dulcamara L.). The present study utilized high resolution melting analysis of the B. cockerelli mitochondrial cytochrome c oxidase I gene to assess the psyllid populations occurring on S. dulcamara during the summer and winter months in Washington, Oregon, and Idaho. This technique has previously been used to analyze the cytochrome c oxidase I gene of B. cockerelli, and has identified four psyllid haplotypes. Lso infection was also determined for the psyllids collected from S. dulcamara. During both the summer and the winter months in the Pacific Northwest, the Northwestern psyllid haplotype was the predominant population found living on S. dulcamara. However, low levels of the Western psyllid population were also present in Washington and Oregon during the same period. No overwintering psyllids tested were Lso-infected, suggesting that these populations do not pose an imminent threat of Lso transmission to newly emerging potatoes and other solanaceous crops in the region, unless a source of Lso becomes available.
      PubDate: 2013-12-01
       
  • Stability and Broad-Sense Heritability of Mineral Content in Potato:
           Potassium and Phosphorus
    • Abstract: Abstract In the study of nutritional variability in potato it is desirable to know the present range of expression and genetic potential for increase. Potato breeding lines and varieties in two separate trials were evaluated for potassium and phosphorus content by wet ashing and Inductively Coupled Argon Plasma Emission Spectrophotometer analysis. Stability and broad-sense heritability were determined. Among genotypes, potassium content ranged from 1.85 and 2.49 % DW while phosphorus content ranged from 0.16 to 0.34 % DW over both trials. Genotype by environment interactions were significant in the Tri-State and Western Regional Red/Specialty (WR-R/SP) trials for both potassium and phosphorus, while environments were not. Genotype was a significant source of variation for both minerals in the WR-R/SP trial only. In the Tri-State trials, 7 and 4 of ten clones were unstable before and after removal of environmental heterogeneity, respectively, for potassium content, and 5 and 4 genotypes were unstable before and after removal of environmental heterogeneity, respectively, for phosphorus. In the WR-R/SP Trials, 7 and 3 of 13 clones were unstable before and after removal of environmental heterogeneity, respectively, for potassium content, and 3 and 4 genotypes were unstable before and after removal of environmental heterogeneity, respectively, for phosphorus. Broad sense heritability was low for both potassium and phosphorus in the Tri-State Russet-Skin Trials but high for both potassium and phosphorus in the WR-R/SP Trials. Although potato is a minor contributor of phosphorus to the human diet, it is an important source of potassium. Adult males and females receive 12 % of the Recommended Dietary Allowance of potassium from 100 g of potato. Estimates of broad-sense heritability from these two trials suggest that genotypes with higher levels of both potassium and phosphorus can be selected from within the Red/Specialty market class, but not from within the Tri-State russet class. An increase in potassium content in the potato, for which the daily need in the human body is so high, could be a boon to human health.
      PubDate: 2013-12-01
       
  • Characterization and Distribution of Three New Clonal Lineages of        class="a-plus-plus">Phytophthora infestans Causing
           Late Blight in Wisconsin from 2009 to 2012
    • Abstract: Abstract Phytophthora infestans causes late blight of potato and tomato, a disease that has been estimated to cost U.S. potato growers $287.8 million annually. We collected isolates of P. infestans from Wisconsin from 2009 to 2012 and determined distribution of clonal lineages and mating types and sensitivity to the systemic fungicide mefenoxam. We also sought to evaluate the current utility of an analysis of the Glucose-6-phosphate isomerase (Gpi) allozyme locus for predicting mefenoxam sensitivity with the aim of delivering timely information to growers. Overall, 143 isolates were collected from 52 locations in 20 Wisconsin counties from 2009 to 2012. Three clonal lineages, US-22, US-23, and US-24, were identified and were novel to Wisconsin and the U.S. US-22 is of the A2 mating type and sensitive to mefenoxam, with Gpi 100/122. US-23 and US-24 are of the A1 mating type and primarily intermediately sensitive to mefenoxam, with Gpi 100/100 and 100/100/111, respectively. Because of this close correlation and the unique Gpi patterns for each lineage present, we were able to predict mefenoxam sensitivity directly from samples using the allozyme assay and quickly deliver management information to growers. Both mating types were present in Wisconsin in 2009 and 2010 but were spatially separated and no evidence of sexual recombination or soil persistence was detected. The presence of new clonal lineages of P. infestans in Wisconsin indicates a need for continued close monitoring of late blight to facilitate generation of timely information for enhanced short-term and long-term late blight management.
      PubDate: 2013-12-01
       
  • Effect of Harvest Date on PI2, Total Protein, TGA Content and Tuber
           Performance in Potato
    • Abstract: Abstract Proteinase inhibitor 2 (PI2), isolated from potatoes is associated with the release of cholecystokinin (CCK), a satiety factor in humans. PI2 is the active ingredient of Slendesta® Potato Extract. The effect of harvest date on the levels of proteinase inhibitor 2 (PI2), total protein content and total glycoalkaloids (TGA) was studied in two potato (Solanum tuberosum L.) clonal lines. In addition, tuber specific gravity, tuber yield, and tuber size distribution were measured in response to harvest date. The two potato clonal lines designated as KI-PSt0018 and KI-PSt0034 were planted in a randomized complete block design with four replicates. Tubers were harvested at four different dates during the growing season; 4 weeks and 2 weeks to vine-kill; at vine-kill; and 2 weeks post vine-kill. Sample tubers from these four harvest dates and from 2 months of storage, post vine-kill stage were analyzed for PI2, total protein and TGA. Harvesting at different dates had a significant influence on most of the traits studied in both clonal lines. The two clonal lines responded differently to different harvest dates for all traits except PI2 and specific gravity. PI2 levels increased with maturity with the highest levels observed at full maturity in both clonal lines. The protein levels did not show any specific trend in either clonal line. TGA levels increased gradually in small increments with maturity in KI-PSt0018 but did not have a clear pattern in KI-PSt0034. Tuber yield and size increased with maturity of the crop in both clonal lines. Higher tuber yields were seen during final vine-kill and 2 weeks post vine-kill compared to the earlier stages of harvest in both clonal lines. Tuber specific gravity declined when tubers were left in the ground for 14 to 21 days after vine-kill in both clonal lines. This study indicated harvest of potato prior to vine-kill is not beneficial for the extraction of PI2 for use as functional food or dietary supplement ingredient.
      PubDate: 2013-12-01
       
  • Investigation of Host Responses of Different Potato Genotypes at Tissue,
           Cellular and Subcellular Levels After Infection with        class="a-plus-plus">Phytophthora infestans
    • Abstract: Abstract In histological and cytological investigations, the infection process of Phytophthora infestans, the late blight pathogen, was comparatively studied in several potato cultivars and somatic hybrid genotypes and their parents using fluorescence microscopy and electron microscopy methods. The results showed that germination of zoospores of P. infestans and frequency of invading by infection hyphae did not differ among the cultivar-pathogen interactions, but, extension of hyphae in host cells markedly differed among these genotypes. In the susceptible genotypes the pathogen grew rapidly inter- and intracellularly, 12 h after inoculation (hai), and some digital like haustoria were formed and the cytoplasm of the host cells became disorganized. In the resistance genotypes, the pathogen was restricted to the site of initial penetration, although some hyphae could penetrate the epidermal cell, however, the host cells produced resistance responses, such as formed wall appositions when in contact with hyphae, and no haustoria like structures were found. In the somatic hybride genotypes, the host response was different according to their parents as shown by transmission electron microscopy. In the hybrid genotype 1508/2, like in the wild species S. bulbocastanum, no hyphae were found in host cells. In the other genotypes, hyphae of P. infestans spread intercellularly and formed haustoria, but the cytoplasm of hyphae and haustoria was disorganized and host cell resistant responses often appeared, such as, host cells were disorganized and necrotic and cell wall apposition were observed.
      PubDate: 2013-12-01
       
  • Screening of Iranian Potato Germplasm for Resistance to the Potato
           Tuberworm Phthorimaea
           operculella
    (Lepidoptera: Gelechiidae)
    • Abstract: Abstract The potato tuberworm, Phthorimaea operculella (Zeller), is an important insect pest of potato, Solanum tuberosum L., both in storage and in the field. In this research, tubers of eight commercial potato cultivars and four Iranian selections with equal weight and dormancy were exposed to 10 pairs of adult P. operculella in a climate chamber set at 25 ± 1 °C, 65 ± 5 % RH and total darkness. In a free-choice situation, oviposition was lower on 397082–2, Khavaran and Morene compared to the other germplasm that were exposed to adults of P. operculella. Number of mines per tuber, length of mines per tuber, time of development of larvae, number of pre-pupae produced per tuber, weight of pre-pupae and number of eggs developed in ovaries per female were counted and/or measured on each commercial cultivar and selection. There were fewer and shorter mines on tubers of 397082–2, Khavaran and Morene compared to the other potato germplasm. The number of pre-pupae produced per tuber and the weight of pre-pupae were lower when P. operculella was reared on tubers of 397082–2, Khavaran and Morene. Also the development, survival and fecundity were lower when P. operculella was reared on those same germplasm. Flesh firmness was negatively correlated with larval survival (r 2 = 0.87); in addition, the percentage of starch and macronutrient composition was low on these three germplasm. Thus, tuber flesh firmness of these germplasm could delay larval penetration and lower establishment 397082–2, Khavaran and Morene showed promising traits that can be integral component of potato breeding for resistance to P. operculella and pest management programs.
      PubDate: 2013-08-27
       
 
 
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