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AGRICULTURE (458 journals)                  1 2 3 4 5 | Last

Aceh International Journal of Science and Technology     Open Access  
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: 3)
Advances in Agriculture & Botanics     Open Access   (Followers: 10)
Advances in Agriculture, Sciences and Engineering Research     Open Access   (Followers: 12)
Advances in Agronomy     Full-text available via subscription   (Followers: 11)
Advances in Life Science and Technology     Open Access   (Followers: 6)
AFBM Journal     Open Access  
Africa Development     Open Access   (Followers: 8)
Africa Research Bulletin: Political, Social and Cultural Series     Hybrid Journal   (Followers: 8)
African Journal of Agricultural Research     Open Access   (Followers: 3)
African Journal of Food Science     Open Access   (Followers: 4)
African Journal of Food, Agriculture, Nutrition and Development     Open Access   (Followers: 5)
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: 5)
Agribusiness : an International Journal     Hybrid Journal   (Followers: 5)
Agricultura Tecnica     Open Access   (Followers: 6)
Agricultura Tropica et Subtropica     Open Access   (Followers: 2)
Agricultural Advances     Open Access   (Followers: 4)
Agricultural and Food Science     Open Access   (Followers: 19)
Agricultural Economics     Hybrid Journal   (Followers: 46)
Agricultural History     Full-text available via subscription   (Followers: 218)
Agricultural Research     Hybrid Journal   (Followers: 5)
Agricultural Science     Full-text available via subscription   (Followers: 6)
Agricultural Science     Open Access  
Agricultural Sciences     Open Access   (Followers: 8)
Agricultural Sciences in China     Full-text available via subscription   (Followers: 4)
Agricultural Systems     Hybrid Journal   (Followers: 21)
Agricultural Water Management     Hybrid Journal   (Followers: 15)
Agriculture     Open Access   (Followers: 5)
Agriculture & Food Security     Open Access   (Followers: 12)
Agriculture (Poľnohospodárstvo)     Open Access   (Followers: 1)
Agriculture and Agricultural Science Procedia     Full-text available via subscription   (Followers: 1)
Agriculture and Human Values     Hybrid Journal   (Followers: 11)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 32)
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: 14)
American Journal of Economics and Sociology     Hybrid Journal   (Followers: 20)
American Journal of Potato Research     Hybrid Journal   (Followers: 2)
American Journal of Rural Development     Open Access  
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: 21)
Applied Financial Economics Letters     Hybrid Journal   (Followers: 7)
Arboricultural Journal : The International Journal of Urban Forestry     Hybrid Journal   (Followers: 6)
Archivos de Zootecnia     Open Access   (Followers: 2)
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: 4)
Asian Journal of Plant Sciences     Open Access   (Followers: 2)
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   (Followers: 1)
Bangladesh Journal of Agricultural Research     Open Access   (Followers: 2)
Bangladesh Journal of Scientific Research     Open Access   (Followers: 1)
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: 21)
Biodiversity : Research and Conservation     Open Access   (Followers: 20)
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)

        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  [2210 journals]   [SJR: 0.639]   [H-I: 26]
  • The Influence of Ethephon Application Timing and Rate on Plant Growth,
           Yield, Tuber Size Distribution and Skin Color of Red LaSoda Potatoes
    • Abstract: Abstract Optimizing the response of growth regulators depends in part on finding the most appropriate application rate and timing. Preliminary trials indicate that ethephon (2-chloroethylphosphonic acid) may be useful for improving potato (Solanum tuberosum L.) tuber appearance and skin color of red-skinned cultivars, but relatively little is known about optimum application practices. Two separate trials were conducted at the University of Idaho Parma Research and Extension Center to evaluate the effect of ethephon foliar application timing and rate on plant growth, tuber yield, size distribution, and skin color of the cultivar Red LaSoda. Skin color was rated visually and by colorimeter at harvest and periodically throughout storage at 4 °C. In 2011, ethephon application timing did not influence plant height, total yield, tuber size or skin color but did affect some tuber size classes. In contrast, all of these parameters were significantly influenced by application timing in 2012. The optimum application timing to influence skin color was a relatively narrow window during initial flower development, to 10 days after initial flowering (coinciding with tuber initiation). Increasing rates of ethephon significantly reduced plant height, increased foliar injury symptoms, and reduced average tuber size, but did not influence total yield in Red LaSoda. Higher ethephon rates resulted in significantly darker tuber skin (lower L* values) and increased red color (increased chroma and reduce hue angle values) when compared to the non-treated control. Evaluation of samples held in storage showed that differences in skin color ratings at harvest were maintained throughout the storage period. It is concluded that two foliar applications of ethephon at a rate between 292 and 438 ml ha−1applied ten days apart, initiated at pre-bloom, will provide the optimum change in skin color and reduce average tuber size without reducing total yield.
      PubDate: 2014-11-08
  • Mechanical Transmission of Potato Virus Y (PVY) Through Seed Cutting and
           Plant Wounding
    • Abstract: Abstract The transmission of PVY strains, PVYO, PVYN:O, and PVYNTN via tuber cutting and plant wounding was investigated in PVY susceptible cultivars Shepody and Russet Norkotah. For the tuber cutting experiment, after one infected tuber was cut with a knife, four uninfected tubers were cut sequentially with the same knife without disinfecting it between the cuts. In the plant wounding experiments, wounds were induced in the healthy and infected plants of Shepody by bouncing, brushing, hammering, squeezing, and Carborundum rubbing treatments. These treatments allowed exchange of sap between the healthy and infected plants. Results demonstrated that seed cutting did not transmit PVY, whereas plant wounding treatments caused varying levels of PVY transmission, depending on the wounding treatment. Plant bouncing was the least effective whereas hammering was the most effective.
      PubDate: 2014-11-01
  • Infection Risk Potential of South American Spongospora subterranea f.sp.
           subterranea Root Gall and Tuber Lesion Inoculum on Potato ( Solanum
           tuberosum ssp. tuberosum )
    • Abstract: Abstract Spongospora subterranea f. sp. subterranea causes the potato diseases powdery scab on tubers and galls on roots, and occurs in most potato production areas worldwide. The pathogen was probably introduced to Europe from South America in the 16th century. Three different genotype clusters have been found worldwide: the genetically variable groups from South America (native), and, in contrast, the nearly clonal group outside South America (invasive). An inoculation experiment was carried out with the long-day potato host ‘Agria’ comparing three different native Spongospora resting spore inocula with an invasive one, to determine the infection risk potential on a widely grown potato subspecies. All inocula led to root infection. Invasive tuber lesion sporosori from ‘Agria’ produced the greatest amount of infection, whereas the tuber lesion inoculum from the Venezuelan S. tuberosum ssp. tuberosum host and the root gall inoculum from the Colombian S. phureja host caused the least infections. The inoculum genotypes corresponded to all of the three previously described groups. Most root galls showed the invasive group type, independent of the inoculum. These results suggest that the most successful invasive genotype is still present in native pathogen populations and emphasize the need for continued quarantine vigilance to prevent new virulent recombinants of the pathogen.
      PubDate: 2014-11-01
  • Rapid Cycling of Potato Tuber Generations by Overcoming Dormancy
    • Abstract: Abstract Dormancy hinders progress in attempts to fast track potato tuber generations. In this study, we evaluated the ability of gibberellic acid (GA) to overcome dormancy in freshly harvested tubers of 11 potato cultivars in 2 years of field trials. Tubers were wounded and dipped in 0, 10, 100, and 1,000 ppm GA. Then they were planted in the field 5 days later. Vine length and stem number were measured throughout the season. Tubers were also harvested and weighed. Cultivars varied in their response to GA treatment. However, for all cultivars, wounding followed by treatment with 10 or 100 ppm effectively overcame dormancy. The 1,000 ppm treatment produced excessive vine growth and lower yield compared to the lower concentrations. Consequently, wounding of freshly harvested tubers, followed by a dip in 10 or 100 ppm GA is recommended to overcome tuber dormancy in programs interested in rapid cycling.
      PubDate: 2014-10-11
  • Relationship Between Plant Vascular Architecture and Within-Plant
           Distribution of ‘Candidatus Liberibacter solanacearum ’ in
    • Abstract: Abstract ‘Candidatus Liberibacter solanacearum’ is an important pathogen of Solanaceous crops that causes zebra chip disease of potato. This pathogen is transmitted among plants by the potato psyllid Bactericera cockerelli. Within-plant spatial variability in Liberibacter infection impedes the ability to detect the bacterium before the onset of visible symptoms. The goal of our study was to test whether vascular architecture of potato explains the uneven distribution of Liberibacter after inoculation of leaves. The movement of rhodamine B among leaves was used to identify vascular connectivity among leaves. Three weeks after inoculating a single leaf with Liberibacter, the pathogen infected significantly more leaflets that had direct vascular connectivity with the inoculated leaf than leaflets with minimal connectivity. In a separate study, significantly more psyllids confined to whole leaves with direct vascular connectivity to a Liberibacter-infected leaf acquired the pathogen than did psyllids confined to leaves with indirect or partial connectivity to the infected leaf. Using fluorescence in situ hybridization, the pathogen was observed in the inner and outer phloem above and below the export leaf, respectively, corresponding with passive movement of Liberibacter in the phloem. Results of this study indicate that the distribution of Liberibacter in potato is at least partly limited by vascular architecture. This knowledge should improve the design of sampling methods to detect Liberibacter in asymptomatic plants.
      PubDate: 2014-10-11
  • A Multi-Year Survey of Stem-End Chip Defect in Chipping Potatoes ( Solanum
           Tuberosum L.)
    • Abstract: Abstract One of the most serious tuber quality concerns of US chip potato growers is stem-end chip defect, which is defined as a localized post-fry discoloration in and adjacent to the vasculature on the stem end portion of potato chips. The severity and incidence of stem-end chip defect vary with growing location and variety, but quantitative data describing this are not available. A multi-year and location study was conducted to evaluate chipping potato varieties for tolerance to stem-end chip defect formation and to quantify defect severity and incidence regionally and temporally. It was observed that higher night temperature in July and August compared to the regional 30-year history was consistently associated with higher SECD severity. Average SECD severity was linearly correlated with incidence of chips having severe SECD. Chip color and tuber stem-end glucose content were significantly correlated with average SECD score across all treatments. Multiple tuber samplings from early growing season to mid post-harvest storage demonstrated that some varieties, such as Nicolet and Pike, had fewer stem-end chip defects than other varieties across years and locations. Stem-end chip defect was rarely observed prior to harvest, but was apparent at the time of harvest on multiple varieties depending on the year and location. Tuber stem-end sucrose and glucose prior to harvest were not indicators of defect development at harvest and out of storage, but pre-harvest chip color was significantly correlated with defect severity 10 weeks after preconditioning was finished.
      PubDate: 2014-10-11
  • Growth Strategies for a Declining Market- the German Fresh Potato Market
    • Abstract: Abstract To determine potential growth strategies for the German fresh potato market, production area, harvested quantities, producer prices and consumption values for the German potato market were examined using trend analysis. German potato harvests were stable over time due to improved growing techniques. Producer longterm prices stayed stable despite their periodic volatility. Overall production area and levels of fresh potato consumption are undergoing a sharp decline. Furthermore, there is a significant relation between total yield and producer prices as dependent variables. In order to compensate for the reduction in consumption, a framework was developed to change the commodity status of fresh potatoes into a differentiated product with new market potential. A consumer and product orientated market segmentation and analysis was applied to the fresh potato market to identify trends and future opportunities. Application of these new differentiated products will help stop the decline of fresh potato consumption by attracting new customers in urban and rural areas. In addition, these new markets are expected to reduce the producer price volatility.
      PubDate: 2014-10-01
  • The Adaptation of Silica Capture RT-PCR for the Detection of Potato Virus
    • 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: 2014-10-01
  • Hill Shape Effect on Yield, Quality, Stolon Length and Tuber Orientation
           of Two Potato Cultivars
    • Abstract: Abstract Potato (Solanum tuberosum L.) cultivars are mostly planted using similar seed piece planting depths and hill shapes even though cultivars have unique tuber and stolon characteristics. A hill-shape study was conducted at Aberdeen, Idaho to determine the effects of hill shape on yield and field-green tuber yields and quality along with stolon length and tuber spatial orientation for two potato cultivars, 'Defender' and 'Summit Russet.' Plots were planted in late April to early May. Prior to emergence four hill shapes were formed: 1) plant-and-drag, 2) broad, 3) normal, and 4) peaked. Defender had higher total yield with the broad hill, but there were no differences among the remaining three hill shapes. For Defender, U.S. No. 1 yield was lower with the plant-and-drag hill shape, and the normal and peaked hills produced lower field-green tuber yield. Hill shape had no effect on total, U.S. No. 1, or field-green tuber yields of Summit Russet. The peaked hill resulted in a deeper uppermost tuber for Defender, while the uppermost tuber was deeper in the normal and peaked hills for Summit Russet. The broad hill resulted in a larger average tuber size for Defender, but hill shape had no effect on tuber size for Summit Russet. Total number of tubers per plant, stolon length and tuber spatial orientation were not affected by hill shape for either cultivar. Hill shape and height are important considerations in maximizing yield of saleable tubers, so needs to be customized according to cultivar-dependent stolon length and tuber orientation characteristics.
      PubDate: 2014-10-01
  • The Use of Mineral Oil in Potato Protection: Dynamics in the Plant and
           Effect on Potato Virus Y Spread
    • Abstract: Abstract The focus of this study was to evaluate two mineral oils (Superior 70 and Vazyl-Y) in reducing the seasonal spread of Potato Virus Y (PVY). Three concentrations of oil (0, 5, and 10 L ha−1 of Superior 70; 0, 7.5, and 15 L ha−1 of Vazyl-Y) and three spray regimes for both oils (every 3–4, 7, and 10–11 days) were tested. Two weeks after top-kill, two tubers from each of 49 plants free of virus at emergence were harvested from treatment plots, sprouted, and tested for PVY with enzyme-linked immunosorbent assay (ELISA). Results revealed that in the case of Superior 70, PVY spread in mineral oil treated plots ranged from 2.1 to 12.2 %, while in the control plots it ranged from 20.4 to 37.7 % across three cultivars. In the case of Vazyl-Y, PVY spread in mineral oil treated plots ranged from 2.1 to 26.5 %, while in the control plots it ranged from 49.9 to 85.7 % across three cultivars. These data show that there was a significant reduction in PVY due to spray of mineral oils. In addition, mineral oil was quantified in plants from the Superior 70 treated and the control plots to understand the dynamics of mineral oil during the season. While there was little to no oil measured in the leaves at the early stages of plant growth, a considerable amount of mineral oil was detected close to plant maturity. A basic model of the concentration of oil in the treated foliage was formulated to confirm our understanding of the factors at play. The model could explain from 50 to 90 % of the variation in oil content observed in the field. Plant growth and size are important factors affecting oil content in mineral oil treated foliage.
      PubDate: 2014-10-01
  • Molecular Analysis of Phytophthora infestans (Mont.) de Bary from
           Chapingo, Mexico. Phylogeographic Referential
    • Abstract: Abstract An Andean origin of Phytophthora infestans was originally based on written records, and recently inferred from mitochondrial and nuclear gene genealogies, which emphasize a common South American origin of the European isolates, and absence of the I-b haplotype in Mexico (recently identified in Tlaxcala, Mexico). In order to compare such results, we sequenced the nuclear genes β-tubulin, Ras, and Intron Ras, and rDNA ITS regions in 24 P. infestans genotypes isolated, identified, and selected, during three crop growing cycles in Chapingo, Mexico. The pathogen showed homology and 100 % sequence similarities to the ones reported for the Andes and Europe β-tubulin, Ras, and Intron Ras genes. Results for the ITS region were inconclusive. The molecular oomycete similarities from the three geographical regions (South America, Europe, and Mexico), and the Mexican genotypes characteristics reported in the species supports the hypothesis of the location of P. infestans diversity and a center of dispersal in the central highlands of Mexico.
      PubDate: 2014-10-01
  • 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: 2014-10-01
  • 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: 2014-10-01
  • 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: 2014-10-01
  • Variation in Bactericera cockerelli (Hemiptera: Triozidae) Oviposition,
           Survival, and Development on 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: 2014-10-01
  • A Draft Genome Sequence Reveals the 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: 2014-10-01
  • 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: 2014-10-01
  • 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: 2014-10-01
  • The Pink Eye Syndrome Does Not Impair Tuber Fresh Cut Wound-Related
    • Abstract: Abstract The potato tuber pink eye (PE) syndrome is a costly physiological disorder that results in corruption of the native periderm, susceptibility to infection, water vapor loss and associated shrinkage, roughened and cracked tuber surfaces, and various related blemishes and defects. PE results in aberrant internal suberin deposition without overt induction by a wound, yet little is known of the effect of PE on wound healing. Herein, we determined the effect of the PE syndrome on basic wound-healing processes: reduction of water vapor loss, suberization and induction of the wound-related hormones abscisic acid (ABA) and jasmonic acid (JA). There was no significant difference in reduction of water vapor loss, rate of accumulation of suberin biopolymers or induction of ABA and JA biosynthesis during wound healing in PE vs. control tubers. These results are important because they indicate that the PE syndrome does not induce a systemic effect that adversely impacts these crucial wound-related processes throughout the tuber, including those areas of the tuber that have no detectable PE symptoms.
      PubDate: 2014-10-01
  • Use of Hill Shape with Various Nitrogen Timing Splits to Improve
           Fertilizer Use Efficiency
    • Abstract: Abstract The efficient use of fertilizer nitrogen (N) is critical for potato production in regions with sandy soils as concerns for groundwater contamination have become more apparent. The interactive effects of different hill shapes and distribution of in-season N fertilizer applications at various timings were evaluated in a 3-year potato (Solanum tuberosum L. cv. Russet Burbank) field experiment on a sandy soil in central Wisconsin. A split-plot design was used with hill shape (standard, shaped-plateau, or pointed) as the main plots and 202 kg N ha−1 divided into two, three, or four applications as the split plots. Broader, flatter hills provided tuber yield increases of 7 to 10 %, tuber size and grade improvements of 8 to 25 %, and increased tuber N uptake an average of 22 % in some years; however, post-emergence hilling operations negatively affected yield and tuber size and grade out in 1 of 2 years. Splitting the N into three in-season applications (emergence, early tuberization, and tuberization + 20 days) increased tuber yield by about 4 % or tuber size by 19 % in years where rain increased leaching potential on this sandy soil, but further splitting increased the proportion of small tubers that passed a 5.1-cm screen. This study confirmed that more blocky-shaped hills with only one hilling operation at emergence can significantly benefit potato yield and quality, and fertilizer N use efficiency on these sandy soils.
      PubDate: 2014-10-01
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