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  Subjects -> AGRICULTURE (Total: 660 journals)
    - AGRICULTURAL ECONOMICS (71 journals)
    - AGRICULTURE (443 journals)
    - CROP PRODUCTION AND SOIL (84 journals)
    - DAIRYING AND DAIRY PRODUCTS (25 journals)
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AGRICULTURE (443 journals)                  1 2 3 4 5 | Last

Acta agriculturae Slovenica     Open Access   (Followers: 5)
Acta Agrobotanica     Open Access   (Followers: 3)
Acta Agronomica Hungarica     Full-text available via subscription   (Followers: 1)
Acta Agronomica Sinica     Full-text available via subscription   (Followers: 6)
Acta Scientiarum. Animal Sciences     Open Access   (Followers: 1)
Acta Scientiarum. Technology     Open Access   (Followers: 1)
Acta Technologica Agriculturae     Open Access   (Followers: 1)
Advances in Agriculture & Botanics     Open Access   (Followers: 10)
Advances in Agriculture, Sciences and Engineering Research     Open Access   (Followers: 10)
Advances in Agronomy     Full-text available via subscription   (Followers: 11)
Advances in Life Science and Technology     Open Access   (Followers: 5)
AFBM Journal     Open Access  
Africa Development     Open Access   (Followers: 6)
Africa Research Bulletin: Political, Social and Cultural Series     Hybrid Journal   (Followers: 6)
African Journal of Agricultural Research     Open Access   (Followers: 1)
African Journal of Food Science     Open Access   (Followers: 1)
African Journal of Food, Agriculture, Nutrition and Development     Open Access   (Followers: 1)
African Journal of Horticultural Science     Open Access   (Followers: 2)
African Journal of Range and Forage Science     Hybrid Journal   (Followers: 5)
African Journal of Sustainable Development     Full-text available via subscription   (Followers: 3)
Agribusiness : an International Journal     Hybrid Journal   (Followers: 5)
Agricultura Tecnica     Open Access   (Followers: 5)
Agricultura Tropica et Subtropica     Open Access   (Followers: 1)
Agricultural Advances     Open Access   (Followers: 3)
Agricultural and Food Science     Open Access   (Followers: 14)
Agricultural Economics     Hybrid Journal   (Followers: 44)
Agricultural History     Full-text available via subscription   (Followers: 149)
Agricultural Research     Hybrid Journal   (Followers: 2)
Agricultural Science     Full-text available via subscription   (Followers: 5)
Agricultural Sciences     Open Access   (Followers: 7)
Agricultural Sciences in China     Full-text available via subscription   (Followers: 3)
Agricultural Systems     Hybrid Journal   (Followers: 19)
Agricultural Water Management     Hybrid Journal   (Followers: 13)
Agriculture     Open Access   (Followers: 4)
Agriculture & Food Security     Open Access   (Followers: 9)
Agriculture (Poľnohospodárstvo)     Open Access   (Followers: 1)
Agriculture and Agricultural Science Procedia     Full-text available via subscription  
Agriculture and Human Values     Hybrid Journal   (Followers: 10)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 29)
Agriprobe     Full-text available via subscription  
Agrivita : Journal of Agricultural Science     Open Access   (Followers: 4)
Agro-Science     Full-text available via subscription  
Agroalimentaria     Open Access   (Followers: 1)
Agrociencia     Open Access   (Followers: 2)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Agronomía Colombiana     Open Access   (Followers: 1)
Agronomía Costarricense     Open Access   (Followers: 2)
Agronomía Mesoamericana     Open Access   (Followers: 1)
Agronomie Africaine     Full-text available via subscription  
Agronomy     Open Access   (Followers: 8)
Agrosearch     Open Access  
AI & Society     Hybrid Journal   (Followers: 2)
Alinteri Zirai Bilimler Dergisi : Alinteri Journal of Agricultural Sciences     Open Access  
Ambiência     Open Access  
Ambiente & Agua : An Interdisciplinary Journal of Applied Science     Open Access   (Followers: 1)
American Journal of Agricultural and Biological Sciences     Open Access   (Followers: 9)
American Journal of Botany     Full-text available via subscription   (Followers: 13)
American Journal of Economics and Sociology     Hybrid Journal   (Followers: 19)
American Journal of Potato Research     Hybrid Journal   (Followers: 2)
Anais da Academia Brasileira de Ciências     Open Access   (Followers: 2)
Annales UMCS, Agricultura     Open Access  
Annales UMCS, Horticultura     Full-text available via subscription  
Annals of Agricultural and Environmental Medicine     Open Access   (Followers: 1)
Annals of Agricultural Sciences     Open Access   (Followers: 1)
Annual Review of Resource Economics     Full-text available via subscription   (Followers: 10)
APCBEE Procedia     Partially Free   (Followers: 2)
Applied Economics Letters     Hybrid Journal   (Followers: 18)
Applied Financial Economics Letters     Hybrid Journal   (Followers: 5)
Arboricultural Journal : The International Journal of Urban Forestry     Hybrid Journal   (Followers: 6)
Archivos de Zootecnia     Open Access  
Arquivos do Instituto Biológico     Open Access  
Arthropod-Plant Interactions     Hybrid Journal   (Followers: 1)
Asian Economic Papers     Hybrid Journal   (Followers: 3)
Asian Journal of Agricultural Research     Open Access   (Followers: 2)
Asian Journal of Plant Sciences     Open Access   (Followers: 1)
Australian Cottongrower, The     Full-text available via subscription   (Followers: 1)
Australian Economic Papers     Hybrid Journal   (Followers: 5)
Australian Forest Grower     Full-text available via subscription   (Followers: 2)
Australian Forestry     Full-text available via subscription   (Followers: 4)
Australian Grain     Full-text available via subscription   (Followers: 4)
Australian Holstein Journal     Full-text available via subscription  
Australian Journal of Agricultural and Resource Economics     Hybrid Journal   (Followers: 5)
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   (Followers: 1)
Bangladesh Journal of Scientific Research     Open Access  
Berkala Ilmiah Pertanian     Open Access   (Followers: 1)
Bioagro     Open Access   (Followers: 1)
Biocatalysis and Agricultural Biotechnology     Hybrid Journal   (Followers: 5)
Biocontrol Science and Technology     Hybrid Journal   (Followers: 5)
Biodiversity     Hybrid Journal   (Followers: 16)
Biodiversity : Research and Conservation     Open Access   (Followers: 17)
Biological Agriculture & Horticulture : An International Journal for Sustainable Production Systems     Partially Free   (Followers: 13)
Biosystems Engineering     Hybrid Journal   (Followers: 1)
Biotemas     Open Access  
Bragantia     Open Access   (Followers: 2)
Brazilian Archives of Biology and Technology     Open Access   (Followers: 1)
British Poultry Science     Hybrid Journal   (Followers: 5)
California Agriculture     Open Access   (Followers: 1)

        1 2 3 4 5 | Last

Journal Cover 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  [2209 journals]   [SJR: 0.639]   [H-I: 26]
  • Assessment of Possibilities of Microtuber and in vitro Plantlet Seed
           Multiplication in Field Conditions. Part 1: PVY, PVM and PLRV Spreading
    • Abstract: Abstract Currently in vitro plantlets and microtubers provide the basis for pre-base production of potato seeds, from which minitubers are produced under covers – they serve later as seed material to be planted in the field. The aim of the research was to determine the possibility for multiplication of material produced in vitro directly in field conditions. The research assessed PVY, PVM and PLRV infection of potato tubers derived from plants grown directly from in vitro plantlets, microtubers, minitubers and traditional seed potatoes planted in the field at different times. Moreover, testing in laboratory conditions, the susceptibility of these plants to virus infection was determined for the case of artificial inoculation of Myzus persicae and Aphis nasturtii. It was found that the infection of tubers derived from in vitro plantlets and microtubers was greater than that of seed potatoes and minitubers. Yet it seems that the reason for their higher infection level resulted not from the plant’s sensitivity or its greater attractiveness to aphids but from a largely unknown cause. Earlier planting of microtubers and in vitro plantlets in the field in case of the more resistant cultivar and certainly later in relation to the main time of planting had an impact on limiting the PVY and PVM infection of potato tubers. Hence multiplication of microtubers and in vitro plantlets in field conditions could be very economical using cultivars which are relatively resistant to viruses. However, adopting a later than usual planting period (end of June) and applying an additional protective cover (such as non-woven agricultural fabric) in the first period of a plant’s growth, promotes multiplication of microtubers and in vitro plantlets in field conditions for cultivars with low resistance levels.
      PubDate: 2014-05-02
       
  • Aggressiveness of Phytophthora
           
    • Abstract: Abstract Epidemics of late blight on potato in the semiarid Pacific Northwest since 1991 have been characterized by a prevalence of stem lesions in relation to leaf lesions. This study was conducted in 1997 to test the hypothesis that isolates representing immigrant strains of Phytophthora infestans were more adapted at causing stem lesions and more aggressive at higher temperatures than isolates representing the relatively older US-1 strain. A total of 23 Phytophthora infestans isolates representing US-1, US-8, and a new A1 compatibility type strain were tested for aggressiveness on leaflets and stems of whole potato plants (cv. Russet Burbank) in 11 trials. Plants in one set of trials were incubated at constant temperatures of 18, 23, and 28 °C for six days with a 16 h photoperiod. Plants in the second set of trials were incubated at the same three day temperatures but the night temperature in all treatments was reduced to 16 °C. Lesion establishment was recorded, and daily severity readings were used to calculate the area under the lesion expansion curve (AULEC). Lesion area, sporulation frequency, sporulation time, and sporulation capacity were also measured. Lesion establishment was higher on stems than on leaves for isolates of all strains. Isolates representing US-8 and new A1 strains often had higher AULEC values but had similar lesion establishment, sporulation frequency, sporulation time, and sporulation capacity values as US-1 isolates. A reduction in components of aggressiveness for all strains was noted at 28 °C, with leaflets being more affected than stems. Sporulation rarely occurred at 28 °C. Few differences in components of aggressiveness were observed between 18 and 23 °C. These findings indicate that isolates from the relatively newer strains (US-8 and new A1) were not better adapted in causing lesions on potato stems than isolates from the old US-1 strain, nor were they better adapted to higher temperatures. The relatively newer strains, however, were generally more aggressive as indicated by higher AULEC on stems and leaflets over the range of temperatures used in this experiment.
      PubDate: 2014-04-26
       
  • Luxury Absorption of Potassium by Potato Plants
    • Abstract: Abstract Pot and field experiments were conducted to test whether excessive potassium (K) uptake by potato plants occurs under conditions with or without irrigation at different sites. The results from both pot and field experiments showed that potato biomass and tuber yield peaked at a certain level of external K, and did not increase further with additional K supply. However, K absorption by potato plants continued to increase within the range of K used. It was concluded that luxury absorption of K by potato plants occurred with high K availability in the media. This suggests that K fertilizer recommendation based on the index “K requirement per tuber production” may be unreliable, because the optimum crop need varies with production conditions.
      PubDate: 2014-04-10
       
  • Variation in Bactericera cockerelli
           (Hemiptera: Triozidae) Oviposition, Survival, and Development on        class="a-plus-plus">Solanum bulbocastanum
    Germplasm
    • Abstract: Abstract The potato psyllid, Bactericera cockerelli, is a key pest of potato and important vector of the pathogen that causes zebra chip disease. Control of zebra chip relies entirely on the use of insecticides to reduce populations of this vector. The development of potato varieties resistant to B. cockerelli would contribute to cost-effective control of this insect. Wild potato germplasm are key sources for desirable traits including pest resistance to develop new potato cultivars. Our objective was to screen Solanum bulbocastanum germplasm for resistance to B. cockerelli. The combined use of choice and no-choice assays demonstrated considerable variability among S. bulbocastanum populations in their susceptibility to psyllids. At least six S. bulbocastanum populations exhibited resistance to B. cockerelli: PI 243512, PI 243513, PI 255518, PI 275194, PI 275197, and PI 283096. The documentation of the variability among S. bulbocastanum germplasm populations in their susceptibility to B. cockerelli can aid the development of potato cultivars that are naturally resistant to the potato psyllid.
      PubDate: 2014-04-02
       
  • Molecular Analysis of Potatoes from the Pacific Northwest Tri-State
           Variety Development Program and Selection of Markers for Practical DNA
           Fingerprinting Applications
    • Abstract: Abstract DNA fingerprinting is a valuable tool for plant cultivar discrimination and identification. Simple Sequence Repeat (SSR) markers represent an excellent option for obtaining DNA fingerprints of potatoes in an easy, fast, and reliable fashion. The highly polymorphic and co-dominant nature of SSRs gives them good discrimination power to declare the distinctiveness of new potato clones for Plant Variety Protection (PVP) and to properly identify existing cultivars. They are also useful for confirming origin and avoiding duplications and mixtures in breeding, foundation and certification programs, and also during growing and marketing stages. A total of 54 (50 tetraploid and 4 diploid) potato clones, including new cultivars released by the Pacific Northwest Tri-State Potato Variety Development Program and a set of common commercial cultivars, were analyzed using 25 SSR markers. Marketing classes (French fry processing, fresh market, and chip processing) were clearly separated using those markers. We have empirically selected a subset of six SSRs that differentiate all the potato varieties and clones present in the study. This subset of six SSR markers could be used for practical DNA fingerprinting. In order to declare distinctiveness, we recommend that common reference varieties always be genotyped together with the newly tested potato clones and that focus be placed on the relative allelic differences between the new clones and the reference varieties.
      PubDate: 2014-04-01
       
  • Environmental Concerns of Phosphorus Management in Potato Production
    • Abstract: Abstract Phosphorus (P) losses from agricultural systems are a cause of degraded surface water quality of lakes and streams. In freshwater systems, P is often the most limiting nutrient for algae growth and an increase in P additions to these systems can cause a shift in ecology. These shifts can result in a degradation of the water resource as habitat or for recreation. In an effort to combat the negative effects of agriculture management practices on surface water quality, federal and state regulations require some level of assessment to guide P applications. Areas with large amounts of potato production are of particular concern with respect to P loss since potatoes are a high P demanding crop and are inefficient users of applied P. In many cases, soils in potato production are managed with a higher soil test P concentration compared to other crops and P applications for optimum production exceed P removal. When potato production fields are maintained at high soil test P levels, this may increase the risk of P loss in runoff. However, based on soils and landscape positions where potatoes are grown, there may be little risk of transport. While there appears to be little risk of P loss on low-sloping, sandy soils, output from the Wisconsin Phosphorus Index suggests that more steeply sloping fields can pose some risk, especially when soil test P concentrations exist at above optimum levels. At high soil test P levels, no P may be required for optimum yield in rotated crops, but production practices of these crops may need to be altered to reduce P losses. Furrow-irrigated and tile-drained fields may also pose risks of P loss to the environment. While the P demands of potato are greater than those for most crops, it is likely that most of this P will not be exported via surface runoff. Careful management considerations must be made when producing potatoes on high sloping soils, especially those close to surface water bodies. Future considerations of P management and water quality will focus on assessing leaching risk of P and this contribution to surface waters.
      PubDate: 2014-04-01
       
  • Improving Phosphorus Use Efficiency Through Potato Rhizosphere
           Modification and Extension
    • Abstract: Abstract Phosphorus (P) fertilization is essential for societal sustainability. However, plant P uptake is inefficient due to poor soil P solubility, especially for the potato (Solanum tuberosum L.) plant due to its relatively poor rooting efficiency. Phosphorus use efficiency (PUE) can be increased with rhizosphere modifications such as: (1) raising the bulk pH of acid soils, (2) placement of fertilizer in the rhizosphere by broadcast incorporation and/or, especially, as a concentrated band, (3) use of slow and controlled release P fertilizers, (4) use of organic acids to increase P solubility in alkaline soils, (5) use of an acid polymer, and (6) extending the effective rhizosphere zone via any practice that fosters root growth, such as through promotion of mycorrhizal development. Alone or in combination, these techniques offer an opportunity to increase PUE.
      PubDate: 2014-04-01
       
  • Response of Potato Genotypes to Bacterial Wilt Caused by        class="a-plus-plus">Ralstonia Solanacearum (Smith)(Yabuuchi
           et al.) In the Tropical Highlands
    • Abstract: Abstract Potato varietal resistance to bacterial wilt disease caused by Ralstonia solanacearum Yabuuchi et al., (Microbiology and Immunology 39:897–904, 1995) is the best management of the disease. Because the causal pathogen exhibits strong host-pathogen-environment interaction, screening the potential parents for resistance under the target growing environmental conditions is the first important step for effective resistance breeding. The objective of this study was to determine the response to bacterial wilt of selected potato genotypes currently grown by farmers in Kenya and candidate clones from the International Potato Center to identify parents that can be used in the local breeding program to develop resistant cultivars. A study was carried out at Kabete, Kenya for three consecutive seasons between November 2011 and February 2013. Thirty six potato genotypes were planted on an inoculated field at the Kenya Agricultural Research Institute (KARI), Kabete using alpha lattice experimental design with three replications. Data collected were days from planting to onset of wilting (DTOW), bacterial wilt incidence (BWI), total tuber weight (ton ha−1) (TTW), total tuber numbers/hectare (TTN), proportion of ware sized tubers (PWTTW), proportion of symptomatic tubers based on weight (PSTTW), proportion of symptomatic tubers based on tuber numbers (PSTTN) and latent infection (LI) of the tubers. Almost, all the potato genotypes evaluated in this study were susceptible to bacerial wilt. Ranking of genotypes based on resistance differed among the three seasons. On average, the three most resistant genotypes were Kenya Karibu, Kenya Sifa and Ingabire. The study identified eight potato genotypes (Meru, Ingabire, Kenya Karibu, Sherekea, Kihoro, Tigoni, Bishop Gitonga and Cangi) to be used as promising parents for subsequent crosses. The chosen genotypes are prolific in pollen production and popularly grown by Kenyan farmers.
      PubDate: 2014-04-01
       
  • A Stringent and Broad Screen of        class="a-plus-plus">Solanum spp. tolerance Against        class="a-plus-plus">Erwinia Bacteria Using a Petiole Test
    • Abstract: Abstract Blackleg and stem rot caused by coliform bacteria belonging to Dickeya spp. and Pectobacterium spp. (both referred to as Erwinia in this paper) are a problem for potato growers worldwide and no sources of high tolerance are currently present in the cultivated S. tuberosum gene pool. To find sources of tolerance, 532 genotypes from 340 accessions, covering most of the known potato species, were assayed with P. wasabiae, P. carotovorum and D. ‘solani’ species in a petiole test. This petiole test was optimized later on using well responding genotypes from the broad screen. Based on the obtained data, the best developmental stage for cell wall degradation tests was identified to be the 4th-6th youngest leaf. Under the stringent biotic and climatic screening conditions used, only three genotypes were regarded as tolerant against all tested Erwinia species. These genotypes all belonged to the series Yungasensa, this series can be readily crossed with cultivated potato and is considered as a genetic source to upgrade the Erwinia tolerance level of cultivated potato.
      PubDate: 2014-04-01
       
  • Optimizing Phosphorus Fertilizer Management in Potato Production
    • Abstract: Abstract Management of fertilizer phosphorus (P) is a critical component of potato production systems as potato has a relatively high P requirement and inefficiently uses soil P. Phosphorus promotes rapid canopy development, root cell division, tuber set, and starch synthesis. Adequate P is essential for optimizing tuber yield, solids content, nutritional quality, and resistance to some diseases. Although soil test P is the primary tool for assessing P fertilizer needs, in some areas petiole P analysis has been successfully utilized to guide in-season P applications. Potato has been shown in some studies to respond to fertilizer P at soil test levels considered very high for most other crops (100+ mg kg−1 Bray P1 or Mehlich I or III and 20+ mg kg−1 sodium bicarbonate) especially on medium- to finer-textured soils. Even on high-testing soils, fertilizer P rates for top yields sometimes exceed 150 kg P2O5 ha−1. In addition, many states/provinces continue to recommend half or more of the amount of P in the harvested portion of the crop irrespective of soil test P level. In most situations, few differences are expected among fertilizer P sources; however, high rates of diammonium phosphate (DAP) or urea-phosphate (UAP) should not be band-applied in contact or near the seed piece. Most research determined that fertilizer P was most efficiently used when band-applied at planting (e.g., 5 cm to each side of the seed piece); however, some western USA work on high-pH soils showed increased yields and petiole P levels with preplant broadcast applications. In-season applications with the irrigation water can be successful when the potato roots are sufficiently close to the soil surface; however, most research indicates that P applications are more effective when applied at planting or early in the season. Potato fertilizer phosphorus best management practices include: (1) apply the fertilizer P rate calibrated for local soils; (2) band-apply fertilizer P at least 5 cm from the seed piece, especially on very sandy soils or where DAP or UAP are used; (3) use petiole P tests to determine the need for in-season applications; (4) account for all P sources applied, including animal manures; and (5) utilize the best soil conservation practices to reduce P losses to surface waters.
      PubDate: 2014-04-01
       
  • Improving Phosphorus Use Efficiency in the Future
    • Abstract: Abstract World demand for phosphorus (P) fertilizer and increasing environmental regulations concerning water quality will continue to motivate the search for ways to improve P use efficiency in potato production. While much effort has gone into understanding P availability and uptake from soil, relatively little is known about the possibility of increasing uptake efficiency through genetic improvement or improved root health. Potato exhibits considerable genetic variation in uptake efficiency of nutrients like nitrogen, and it is likely that genetic variation also exists in P use efficiency. Increased efficiency may be due to differences in tuber yield per unit of available P (utilization efficiency), or in rate of P absorption from the soil (uptake efficiency). Likewise, genetic improvements in resistance to root-decaying pathogens, such as Verticillium dahliae, and improved control practices are likely to help maintain a healthy root mass to aid in maintaining P uptake during periods of higher P demand during the growing season.
      PubDate: 2014-04-01
       
  • Tomato Spotted Wilt Virus
           Potato Cultivar Susceptibility and Tuber Transmission
    • Abstract: Tomato spotted wilt virus is an economically important pathogen in several potato producing areas in the world. Although natural infections of potato in Serbia have not been detected, two TSWV isolates from tobacco, with different biological features were compared based on NSm gene sequence analysis and they were used for mechanical and graft inoculations to evaluate the susceptibility of five popular potato cultivars: ‘Riviera’, ‘Arnova’, ‘Curoda’, ‘Kondor’ and ‘Aladin’. Both TSWV isolates infected all tested potato cultivars. Statistical analyses showed that the rate of TSWV transmission from infected foliage to tubers and from infected tubers to progeny plants was affected by cultivars, while virus transmission efficiency was independent of investigated isolates. Different potato tissues used for sample preparation did not influence virus detection by ELISA, but composite sampling from six different tuber parts is recommended since it was the most reliable.
      PubDate: 2014-04-01
       
  • Potato Management Challenges Created by Phosphorus Chemistry and Plant
           Roots
    • Abstract: Abstract A primary objective of phosphorus (P) management is to maintain optimal levels of P in the soil solution at the root surface. Potato plants typically have low root density, resulting in higher solution P concentration needs and critical soil test levels than most other common crop plants. The chemistry of P in fertilized soils makes maintaining these high P concentrations a challenge. Phosphorus has a very high affinity for the soil solid phase with iron (Fe) and aluminum (Al) dominating reactions in moderately acid soils and calcium (Ca) in alkaline soils. Guidelines for P stewardship for potato production are: (1) adopt practices that develop soil conditions that favor root growth and development; (2) make source, rate, time and placement decisions for nutrient applications that maintain optimal soil solution P concentrations during critical growth stages; and (3) use soil and water conservation practices to minimize P losses from the root zone and the field.
      PubDate: 2014-04-01
       
  • Proceedings from the 2012 PAA Symposium: Potato Phosphorus Management and
           Utilization for Today and Tomorrow
    • Abstract: Abstract Sustainable management of phosphorus (P) is a critical component of potato production systems because of a comparatively high plant P requirement, soil reactions that create management challenges, and potential environmental degradation from inappropriate P management. Phosphorus affects potato plant growth in many ways including its effects on plant metabolism, cellular structural components, canopy development, tuber set, nutritional quality, and resistance to some diseases.
      PubDate: 2014-04-01
       
  • Tracking the R        class="a-plus-plus"> Mc1
            Gene for Resistance to Race 1 of Columbia Root-Knot Nematode (       class="a-plus-plus">Meloidogyne chitwoodi) in Three Mexican
           Wild Potato Species with Different Ploidies
    • Abstract: Abstract Resistance to Columbia Root-knot nematode was discovered in three wild species in a polyploidy series, Solanum bulbocastanum (2n = 2x), .S. fendleri (2n = 4x), and S. hougasii, 2n = 6x, respectively. After several generations of introgression into the cultivated gene pool, a single dominant monogene conditioning resistance to root propagation of race 1 of CRKN was theorized to be acting in breeding lines derived from each species. Coincidently, sequence tagged sites (STS) and cleaved amplified polymorphic site (CAPS) markers that associated with resistance with S. bulbocastanum were found to be informative in other segregating breeding populations regardless of the source of the gene. The utility of the markers across ploidies suggests that the original gene and genome of S. bulbocastanum or a modern derivative, is present in S. fendleri and S. hougasii. In this polyploidy series, knowledge that the S. bulbocastanum genome is the original source of useful genes guides future germplasm surveyors to search first and most intensively in the primitive Mexican diploid species that may have served as the contributor of a genome to descendants harboring this genome at higher ploidies.
      PubDate: 2014-04-01
       
  • The Adaptation of Silica Capture RT-PCR for the Detection of Potato Virus
           Y
    • Abstract: Abstract In Poland, it is mandatory to index seed tubers for Potato virus Y (PVY), Potato virus M (PVM) and Potato leafroll virus (PLRV). Currently, the incidence of viral infection in seed tubers is determined by grow-out test. Direct testing of tubers after harvest by reverse transcription polymerase chain reaction (RT-PCR) can be beneficial but its application is so far hampered by the high cost of commercial kits for RNA isolation and poor usability of manual methods for routine diagnostics. In this work, we compare several commercial kits with the silica capture RT-PCR (SC-RT-PCR) for direct detection of PVY. The silica capture of RNA in conjunction with optimized PCR conditions facilitates quick and sensitive detection of PVY and offers cost effective and reliable alternative to commercial kits.
      PubDate: 2014-03-08
       
  • A Draft Genome Sequence Reveals the        class="a-plus-plus">Helminthosporium solani Arsenal for
           Cell Wall Degradation
    • Abstract: Abstract Helminthosporium solani is a slow-growing fungal pathogen belonging to the family Massarinaceae. It causes blemishes on potato tubers, affecting processing and fresh market trade. Despite its worldwide distribution, little is known about the biology of H. solani. Here we report the generation of a draft genome sequence of H. solani with an estimated genome size of ~35 megabases, for use in phylogenetic and pathogenicity studies of this fungal pathogen. This sequence is also the first reference genome within the family Massarinaceae. We identified a large suite of genes in the H. solani genome that encode putative cell wall degrading enzymes. Based on comparison with other genomes, we speculate that H. solani is a hemibiotroph or necrotroph. The presence of a large number of genes in the glycoside hydrolase (GH) 10 and 43 families, which aid in the hydrolysis of glucoronoarabinoxylan, also suggests that H. solani may be able to survive on grass hosts and indicates the need to re-examine the life cycle and host range of this pathogen.
      PubDate: 2014-03-08
       
  • Assessing Potato Psyllid Haplotypes in Potato Crops in the Pacific
           Northwestern United States
    • Abstract: Abstract The potato psyllid, Bactericera cockerelli (Šulc), is a vector of the bacterium ‘Candidatus Liberibacter solanacearum’ (Lso) that has been linked to the economically devastating zebra chip disease of potato. To date, four haplotypes of the potato psyllid have been identified and include Central, Western, Northwestern, and Southwestern haplotypes. Zebra chip was reported in potato crops in the Pacific Northwestern United States for the first time in 2011, and the Lso-infected psyllids collected from zebra chip-affected fields were identified as the Western haplotype. Additional studies have reported a mix of the Western and Northwestern psyllid haplotypes in the Pacific Northwest. The present study further examined psyllid population dynamics over the duration of the 2012 potato season in the Pacific Northwest by haplotype analysis of 864 potato psyllids collected from potato fields in Washington, Oregon, and Idaho. In the Yakima Valley of Washington and the lower Columbia Basin of Washington and Oregon, the Northwestern haplotype was predominant (78 %), and was detected earlier in the season than the Western haplotype. Interestingly, in south-central Idaho, all four psyllid haplotypes were identified, but the predominant haplotype was the Western haplotype (77 %). Here, Northwestern psyllids were detected early in the season from June to mid-August, whereas Central psyllids were detected in late July and thereafter. These results suggest that haplotype composition of psyllid populations in potato fields throughout the 2012 growing season in south-central Idaho differed greatly from those in Washington and Oregon. Additionally, all psyllids were analyzed for the presence of Lso, and no Lso-positive psyllids were found in Washington and Oregon, whereas Lso-positive psyllids were found in south-central Idaho. These Lso-positive psyllids consisted of the Western, Northwestern, and Central haplotypes.
      PubDate: 2014-03-01
       
  • Heritability of Yield Components Under Irrigated and Drought Conditions in
           Andigenum Potatoes
    • Abstract: Abstract Drought is one of the major abiotic factors that affect potato production in the tropics and sub-tropics. Molecular plant breeding offers promising opportunities for developing drought tolerant cultivars, but genetic gains to be achieved through breeding depends strongly on the genetic variance and heritability of traits used in the selection process. In the present study, genetic variance and heritability of tuber yield and its components were estimated in the native potato cultivar group Andigenum, expected to include promising drought tolerant progenitors. Twenty-seven full sib families obtained from crossing 18 parents arranged in 3 mating sets were grown under irrigated and terminal drought conditions. Heritability for tuber yield, estimated from female to male variance components was 0.68 and 0.41, respectively, in the irrigated treatment, and only 0.18 and 0.06 under drought conditions. Tuber number was highly significantly correlated to tuber yield but the heritability of this trait (estimated both from female to male variance) was lower than yield heritability and its non-additive genetic variance was higher than its additive genetic variance, particularly when estimated from the female variance component. Heritability of average weight per tuber estimated for male variance component was very high under both irrigated and drought conditions. Its additive genetic variance was much higher than its non-additive genetic variance. However, average weight per tuber correlated to tuber yield within parents but not within families. These results indicate that selection for increased tuber yield under drought conditions in the Andigenum cultivar group may be slow due to its low heritability and high value of non-additive genetic variance. They also suggest that yield components may not be useful as indirect selection criterion for yield, because of their low heritability and/or poor association with yield. The identification of drought tolerance related traits with high heritability and closely associated to tuber yield under drought is consequently required to improve adaptation of potato to drought-prone conditions and efficient utilization of Andigenum potatoes for this purpose.
      PubDate: 2014-02-26
       
  • Matryoshka: A New Floral Mutant in
           Wild Potato
    • Abstract: Abstract A population of the wild potato S. stoloniferum form fendleri (PI 660270) was collected as botanical seeds in the Santa Rita Mountains near Green Valley, Arizona, USA in fall 2010. Original seeds planted for multiplication at the genebank produced two plants with extra whorls of petals, sometimes fused with anthers, and, most remarkably, successive whorls of petals, anthers and carpels nested inside the primary carpel. This mutant was named matryoshka after the similarly nested Russian dolls. Floral morphology of mutants varies. It can have nearly normal male and female fertility in some individuals. Crossing studies indicate that the mutant form is dominant. Expression of the mutant may vary over the flowering cycle of the plant, with earlier flowers appearing mutant and later flowers appearing normal. Tests for pathogens were negative. Flower development mutants are of interest considering the potential for manipulating interspecific crossability, apomixis, and virus elimination in potato, and their usefulness may be extended to the important closely-related fruit crops of tomato, pepper, and eggplant. Matryoshka could also be useful in studies of potato adaptation in the wild: For example, seedless matryoshka fruit may serve as decoys to suppress the seed-eating larvae of Odenicarena fruit flies and Cecidomyiid gall flies which are especially prevalent in the geographic area where the mutant originates.
      PubDate: 2014-02-26
       
 
 
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