bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of viruses on agronomic and brewing characteristics of four hop (Humulus lupulus) cultivars in Australia
Authors: PETHYBRIDGE S J , WILSON C R , HAY F S , LEGGETT G W , SHERRIFF L J 
Published: July 2006

SummaryThe effect of Hop latent virus (HpLV), Hop mosaic virus (HpMV), and Prunus necrotic ring spot virus [PNRSV (apple, A, and intermediate, I, serotypes)], on the survival of softwood cuttings, the vigour (height) of early season growth, cone yield, and the levels of brewing organic acids in mature plants, was assessed in four hop (Humulus lupulus) cultivars in Tasmania, Australia. Virus infections were associated with an increase in the mortality of softwood cuttings following propagation. In all cultivars, height of early growth was a poor indicator of the effect of viruses on cone yield and levels of brewing organic acids (alpha and beta acids). In cv. ‘Nugget’, infection by the virus combinations studied was not associated with reductions in cone yield, however plants infected by PNRSV‐I, in 2000, had 11% lower alpha acids and 7% lower beta acids. In ‘Opal’, infection by HpLV and HpMV were the most deleterious to cone yield, however the effect of HpMV was ameliorated when in combination with PNRSV‐I. Reductions in alpha and beta acid content were attributable only to mixed infections of HpLV + HpMV in combination with either serotype of PNRSV. In ‘Pride of Ringwood’, yield loss was mostly attributable to HpMV and to a lesser extent, HpLV. Some ameliorations in cone yield loss occurred in plants containing a mixed infection between HpMV and HpLV or either of the ilarvirus serotypes. Both of the ilarviruses and HpMV caused reductions in alpha acid content. In ‘Victoria’, cone yield loss was mostly attributable to combinations of viruses such as HpLV + PNRSV‐I and HpLV + HpMV. The deleterious effect of HpLV + HpMV was ameliorated by PNRSV‐A and to a lesser extent, PNRSV‐I. Infection by the virus combinations studied did not significantly affect alpha and beta acid levels in either year. Results suggested the effect of viruses and their combinations differed between cultivars and varied between seasons. This information, when combined with knowledge of the rates of virus re‐infection, can be used to recommend control strategies for the Australian hop industry.
Breeding for resistance to whitefly‐transmitted geminiviruses
Authors: LAPIDOT MOSHE , FRIEDMANN MICHAEL 
Published: July 2006

SummaryGeminiviruses comprise a large and diverse family of viruses that infect a wide range of important monocotyledonous and dicotyledonous crop species and cause significant yield losses. The family Geminiviridae is divided into three genera, one of which is Begomovirus. Species of this genus are transmitted by the whitefly Bemisia tabaci in a persistent, circulative manner and infect dicotyledonous plants. Severe population outbreaks of B. tabaci are usually accompanied by a high incidence of begomoviruses. During the last two decades, there has been a worldwide spread of the B biotype of B. tabaci, accompanied by the emergence of whitefly‐transmitted geminiviruses. Control measures in infected regions are based mainly on limitation of vector populations, using chemicals or physical barriers. However, under conditions of severe whitefly attack, none of these control measures has sufficed to prevent virus spread. Thus, the best way to reduce geminivirus damage is by breeding crops resistant or tolerant to the virus, either by classical breeding or by genetic engineering. A number of begomoviruses have been the subject of much investigation, due to their severe economic impact. This review considers the most severe viral diseases of four major crops (tomato, bean, cassava and cotton). The approaches taken to breed for resistance to these viral diseases should provide a perspective of the issues involved in breeding for begomovirus resistance in crop plants.
Contents and morphological distribution of 2,4‐dihydroxy‐l,4‐benzoxazin‐3‐one and 2‐benzoxazolinone in Acanthus mollis in relation to protection from larvae of Pseudaletia impuncta
Authors: BRAVO H R , COPAJA S V 
Published: July 2006

SummarySecondary metabolites 2,4‐dihydroxy‐l,4‐benzoxazin‐3‐one(DIBOA) and 2‐benzoxazolinone (BOA) were quantified in different morphological parts of A. mollis. The highest DIBOA content was determined in the stamens of the flowers (57.0 umol g−1 fr. wt). Content of DIBOA in leaves decreased from approximately 28 μmol g−1 fr. wt for younger leaves (less than 4 wk old), to 3.0 μmol g−1 fr. wt. for the older ones (more than 13 wk of age). The concentration of BOA was lower than that of DIBOA in all parts of the plant (less than 1.5 μmol g−1 fr. wt) and showed a small variation.Younger leaves exhibit antifeeding activity against the larvae of Pseudaletia impuncta a native moth that feeds on cereals. These results suggest that DIBOA protects A. mollis species from phytophagous insects.
Historical aspects and net CO2 uptake for cultivated Crassulacean acid metabolism plants in México
Authors: NOBEL PARK S , PIMIENTA‐BARRIOS EULOGIO , ZAÑUDO HERNÁNDEZ JULIA , RAMÍREZ‐HERNÁNDEZ BLANCA C 
Published: July 2006

SummaryUse of Crassulacean acid metabolism (CAM) plants in México and worldwide has a long history, but the morphological and photosynthetic aspects of these plants have only been considered recently. Emphasis in this article is on the daily net CO2 uptake ability by three species of agaves and three species of cacti that are currently extensively cultivated in México for beverages, food, fodder, and forage ‐ Agave mapisaga, A. salmiana, A. tequilana, Opuntia ficus‐indica, O. robusta and Stenocereus queretaroensis. Data under controlled conditions are used to help interpret seasonal net CO2 uptake patterns observed in the field. These CAM plants have instantaneous and total daily net CO2 uptake values similar to those for highly productive C3 and C4 crops. The future increase in the cultivated area of CAM plants will have both agronomical and ecological ramifications because of the ability of these plants to endure prolonged drought and to sequester carbon during extended dry periods when few C3 and C4 crops and non‐CAM native plants can fix atmospheric CO2.
Isolation of bacterial consortia for degradation of p‐nitrophenol from agricultural soil
Authors: QURESHI ASIFA A , PUROHIT HEMANT J 
Published: July 2006

Summarybacterial consortium has been isolated containing Pseudomonas spp. strains S1 and S2, which was able to degrade p‐nitrophenol (PNP). The strains were isolated from agricultural soil contaminated with organophosphorus pesticides. Pseudomonas spp. strain S2 could convert p‐nitrophenol to 4‐nitrocatechol (4NC) after pre‐exposure to phenol, when PNP was used as the only carbon source in the medium. Pseudomonas spp. strain S2, when mixed with strain S1 in the ratio 1:5 respectively, decolorised PNP completely.
Strobilurin + acibenzolar‐S‐methyl controls white rust without inducing leaf chlorosis in spinach
Authors: LESKOVAR DANIEL I , KOLENDA KATARZYNA 
Published: July 2006

SummaryWhite rust (Albugo occidentalis) is a major foliar fungal disease of spinach (Spinacea oleracea) in Texas and the Southeastern USA. It causes leaf yellowing, decreasing product quality and marketability. There is a need for evaluating broad spectrum fungicides and new plant defence activators that have the potential to enhance leaf quality in spinach. Two of those fungicides are acibenzolar‐S‐methyl (ACIB) and strobilurin derivatives (STRO). ACIB appears to mimic natural systemic acquired resistance response in plants, while STRO inhibits mitochondrial respiration in fungi. We conducted three consecutive studies to a) determine the effects of ACIB rates and combinations with STRO and mefenoxam + copper hydroxide (MEFE‐Cu) for the control of white rust, and b) evaluate potential phytotoxicity expressed as leaf chlorosis. After two weekly applications in 1998, ACIB, STRO and ACIB + STRO significantly reduced the % of leaf area infected with white rust in the spinach cv. Cascade. In 1999, ACIB + STRO and ACIB + MEFE‐Cu had the best white rust efficacy, with ACIB equally effective when applied at reduced rates. After three applications in 2000, STRO, ACIB + STRO, and ACIB + MEFE‐Cu had significantly lower white rust values than the control, ACIB or MEFE‐Cu. The combination of ACIB + STRO did not cause leaf chlorosis in any year. Use of preventive applications of ACIB + STRO at 7–10 day intervals appear to be an effective strategy to improve leaf quality in spinach.
Effect of different soil and clove treatments in the control of white rot of garlic
Authors: PRADOS‐LIGERO A M , BASCÓN‐FERNANDEZ J , CALVET‐PINÓS C , CORPAS‐HERVÍAS C , LARA RUIZ A , MELERO‐VARA J M , BASALLOTE‐UREBA M J 
Published: July 2006

SummarySoil solarisation was consistently efficacious in reducing inoculum density to undetectable levels in a field naturally‐infested with Sclerotium cepivorum. This treatment delayed epidemic onset of white rot of garlic 2–3 months as compared with the untreated control or the inoculation of planting furrows with Glomus intraradices. Furthermore, significant reductions of disease incidence and of the standardised AUDPC were also observed in solarised plots, resulting in quantitative and qualitative yield improvement. Similar effects were observed in plots planted with tebuconazole‐treated cloves, confirming previous results, whereas Trichoderma harzianum was ineffective as a biocontrol agent, when applied to planting furrows. The inoculation of plots with G. intraradices before planting, in three consecutive years, was neither effective for disease control nor on the development of garlic, although the root systems of garlic plants from all the experimental treatments were heavily mycorrhizal at harvest, indicating the presence of native arbuscular mycorrhizal propagules in the soil and their survival after soil solarisation.
Effects of potassium carbonate as an alternative road de‐icer to sodium chloride on soil chemical properties
Authors: HARTL W , ERHART E 
Published: July 2006

SummaryThe effect of potassium carbonate on soil chemical characteristics was compared with that of the most common de‐icer, sodium chloride, in a 4‐yr outdoor pot experiment with poplar and lime trees. Soil pH was raised more by K2CO3 than by NaCl. Potassium carbonate increased the electrical conductivity mainly in the upper soil layers. When K2CO3 was applied at an average annual dose of 154 g m−2, only the water‐soluble fractions of calcium and magnesium were affected. At an average annual dose of 617 g m−2, total potassium increased by 33% and calcium was displaced from the exchange sites. Calcium saturation was reduced from 85% of the cation exchange capacity in the untreated control to 69% in the higher dose K2CO3 treatment and to 75% in the NaCl treatment. The results show that the negative impact of K2CO3 on soil chemical and osmotic properties is as high as that of NaCl. For plants, however, potassium carbonate in contrast to chloride is not toxic and, applied in moderate doses, may even remedy potassium deficiencies in roadside trees.
Occurrence of three distinct begomoviruses in cassava in Madagascar
Authors: RANOMENJANAHARY S , RABINDRAN R , ROBINSON D J 
Published: July 2006

SummaryThe presence of East African cassava mosaic virus in association with cassava mosaic disease in Madagascar has previously been reported. We now describe virus isolates from mosaic‐affected Madagascan cassava with epitope profiles typical of African cassava mosaic virus, and an isolate with a nucleotide sequence similar to that of South African cassava mosaic virus. Thus, three distinct begomoviruses occur in cassava in Madagascar.
The evaluation of rhizomania resistant sugar beet for the UK
Authors: ASHER M J C , CHWARSZCZYNSKA D M , LEAMAN M 
Published: July 2006

SummarySugar beet rhizomania disease, caused by Beet necrotic yellow vein virus and transmitted by the soil‐borne parasite Polymyxa betae, was first recorded in the UK in 1987. Recently, breeding lines and cultivars with partial resistance to the virus derived from the ‘Holly’ source of resistance have been developed and their suitability for use under UK conditions is explored in this paper. Virus multiplication in the roots of resistant lines exposed to severe disease pressure in glasshouse tests, when quantified by ELISA, was less than one third of that in susceptible controls. More recently developed resistant lines had a lower virus content, on average, largely due to a reduced frequency of susceptible individuals. There was no evidence for resistance to the vector, P. betae, in virus resistant lines. However, the proportion of viruliferous P. betae resting spores in the roots, estimated using the most probable number (MPN) technique, was reduced by at least one third in resistant lines compared with the most susceptible control. A novel line, containing an additional gene to that in ‘Holly’, was the most effective, reducing the infection level to 3% of that in the susceptible control.In two field experiments on severely infested sites, the rate of infection of a resistant line, when assessed by ELISA, was reduced by half compared with a susceptible cultivar and sugar yields of resistant lines were consistently 2–3 times higher than those of susceptible cultivars. In 41 trials on rhizomania‐free sites, several recently introduced resistant lines exhibited sugar yields and agronomic performance comparable to that of three selected high yielding, susceptible cultivars. Results are discussed in relation to the specific UK requirements for rhizomania resistant cultivars. One resistant line, Beta 805 (cv. Concept), fulfilled the requirements for widespread use to control the disease.
Restriction analysis and sequencing of the ITS regions and 5.8S gene of rDNA of Ganoderma isolates from infected oil palm and coconut stumps in Malaysia
Authors: LATIFFAH Z , HARIKRISHNA K , TAN S G , TAN S H , ABDULLAH F , HO Y W 
Published: July 2006

SummaryRestriction analysis and sequencing of the ITS regions and 5.8S gene of rDNA were conducted on 53 Ganoderma isolates from infected oil palm and 15 isolates from coconut stumps to determine their relatedness. Restriction patterns of the ITS regions and 5.8S gene using seven restriction enzymes, namely, Hindlll, EcoRI, BamHI, HaeIII, MspI, Taql and Alul did not produce any patterns that could distinguish between Ganoderma isolates from infected oil palm and coconut stumps. Variations of restriction patterns were observed within and between the two groups of Ganoderma which showed that the isolates were genetically heterogeneous. Based on the dendrogram from cluster analysis of the restriction patterns, the Ganoderma isolates from infected oil palm and coconut stumps were clustered together, indicating a close relationship. Phylogenetic analysis of the nucleotide sequence of the ITS regions and 5.8S gene of 12 Ganoderma isolates using parsimony and distance methods also showed that the two groups of Ganoderma did not cluster separately. Based on the present study, the Ganoderma isolates from infected oil palm and coconut stumps were indistinguishable and closely related which suggests that the coconut stumps in oil palm plantings may have an important role in disease development.
Combining ability for resistance in peanut (Arachis hypogaea) to Peanut bud necrosis tospovirus (PBNV)
Authors: PENSUK V , WONGKAEW S , JOGLOY S , PATANOTHAI A 
Published: July 2006

SummaryThe combining abilities of field resistance to peanut bud necrosis disease (PBND) caused by Peanut bud necrosis tospovirus (PBNV) were examined to understand the type of gene action governing resistance to the disease, and to identify peanut lines suitable for use as parents in a PBND‐resistance breeding programme. The Ft and F2 progenies from a six‐parent diallel cross and their parents were evaluated under field conditions. They were assessed for disease incidence at 30, 40, 50 and 60 days after planting (DAP), and reactions of the lines to the disease could be best differentiated at 50 and 60 DAP. Results indicated highly significant general combining ability (GCA) effects for PBND incidence in F1 and F2 generations. Specific combining ability (SCA) and reciprocal effects were also found to be significant, but their relative contributions to variation among crosses were much less than those of GCA effects. These results suggested that the type of gene action governing resistance to PBND was mainly additive, and selection for PBND resistance in these populations should be effective. Strong correlation coefficients between parental means and GCA effects for disease incidence were seen in both Ft and F2 generations, suggesting that per se performance of the parental line could be used as a predictor of the capability of the line to transmit its PBND‐resistant attribute to progenies. The reciprocal effects were in favour of using resistant lines as female parents. The peanut lines ICGV 86388, 1C 10 and 1C 34 were found to be suitable for use in a PBND–resistance breeding programme.
The incidence of viruses in wild Brassica rapa ssp. sylvestris in southern England
Authors: PALLETT D W , THURSTON M I , CORTINA‐BORJA M , EDWARDS M‐L , ALEXANDER M , MITCHELL E , RAYBOULD A F , COOPER J I 
Published: July 2006

SummaryUsing enzyme‐linked immunosorbent assays, the frequency of occurrence of six viruses was determined in Brassica rapa ssp. sylvestris collected from two Thameside sites (Abingdon and Culham) in Oxfordshire and one near the Avon (Claverton) in Bath & North East Somerset. During 2000–2001, the viruses detected were: Beet western yellows virus (genus Polerovirus) (BWYV), Cauliflower mosaic virus (genus Caulimovirus) (CaMV), Turnip crinkle virus (genus Carmovirus) (TCV), Turnip rosette virus (genus Sobemovirus) (TRoV), and Turnip yellow mosaic virus (genus Tymovirus) (TYMV). BWYV and TYMV were the most frequently detected viruses at the Oxford shire sites, both as single infections (20/1743 and 66/1743 respectively) and as dual infections (7/1743). Turnip mosaic virus (genus Potyvirus) (TuMV) was not detected in the field‐grown plants assayed from any of the sites. There was a highly significant (x2[1]=30.07, P<0.001) difference in the proportion of plants at each Oxfordshire site in which one or more viruses were detected, and essentially the same pattern of virus infection was observed in tests on B. rapa from the site near Claverton. At least one representative isolate of each detected virus was tested for its morphological and serological effects on glasshouse‐grown individuals from different half‐sib families of B. rapa from both Oxfordshire sites. Except for TRoV, where there was a large difference in the frequency of successful infection in B. rapa from the two locations (1/15 vs 11/15), no clear evidence of resistance or immunity to challenge was observed, although tolerance (virus invasion without symptoms) was frequent. Fewer of the plants from Abingdon were infected than those from Culham, when mechanically challenged with TRoV, but the two B. rapa populations were not otherwise consistently different, either in their infectibility by this virus or in their responses to challenge. However, with TCV, viral antigen concentration was closely linked to the severity of disease and the B. rapa from both Oxfordshire sites segregated into two classes: those with symptoms and most viral antigen, and those without symptoms and least viral antigen. These results suggest that generic risk assessments cannot be made due to differences in the way distinct B. rapa populations react to virus challenge.
Stress‐induced changes in the root architecture of white lupin (Lupinus albus) in response to pH, bicarbonate, and calcium in liquid culture
Authors: KERLEY S J , HUYGHE C 
Published: July 2006

SummaryCurrent agronomic cultivars of white lupin (Lupinus albus) are intolerant of calcareous or limed soils. In these soils, high pH, bicarbonate (HCO3−), and calcium (Ca) concentrations are the major chemical stresses to the root system. To determine the responses of the root system to these factors, evaluate root architecture, and compare genotypes for tolerance, a series of liquid culture experiments was completed using root chambers that allowed the study of the root system in two dimensions. Each stress condition caused changes in different parts of the root system and there was no generalised stress response. HCO3− (5 mM) had the greatest effect on cultivars intolerant of calcareous soil; it decreased the dry weight of the shoot and caused the highest percentage of tap root deaths. HCO3− also discriminated between short (determinate) and long (indeterminate) roots, as it decreased the number and density of the determinate roots only. Calcium (3 mM) affected all parts of the root system. The tap root was shortened and showed an increased tortuousness in its path compared with 1 mM Ca, although no plants suffered tap root death. The numbers and densities of the two lateral root forms were also decreased, as were the lengths of the indeterminate roots. Stress from alkaline pH (7.5) media caused a lower number and density of determinate lateral roots to be produced than at pH 6.5. The experiments demonstrated that each culture condition elicited a definable stress response. Stress conditions altered the root architecture of genotypes reported to be tolerant of calcareous soil less than in intolerant genotypes. Although soil is more complex than liquid culture, it is possible that in a calcareous or limed soil each stress condition examined may affect the overall stress of the plant, and increased tolerance may result from tolerance to a single stress.
Detection of Banana streak virus in field samples of bananas from Uganda
Authors: HARPER GLYN , HART DARREN , MOULT SARAH , HULL ROGER 
Published: July 2006

Summary Banana streak virus (BSV) is one of the major constraints to banana production in Uganda. To develop a diagnostic technique, 59 samples were taken from 30 farms at 14 locations across Uganda; a further three samples were taken from infector plants for BSV epidemiology experiments. BSV was found in 51 of the field samples and in the three infector plants. The possible variation of the virus was assessed by serology (ISEM and ELISA) using a broad‐spectrum antiserum and by PCR. Virus was poorly detected in many of the samples by serological tests even though other techniques showed its presence. Virus was detected in most samples by PCR with a degenerate primer set on extracted viral DNA and on immune‐captured (1C) or directly bound (DB) virus particles. The epidemiology experiment samples did not give a product with these degenerate primers but did with other primer sets. A diagnostic procedure was developed involving concentrating the virus in sap by polyethylene glycol precipitation followed by 1C‐ or DB‐PCR using a degenerate primer set which detected virus in most samples.
Patchouli virus X, a new potexvirus from Pogostemon clabin
Authors: FILHO P E MEISSNER , RESENDE R de O , LIMA M I , KITAJIMA E W 
Published: July 2006

SummaryThis work describes a potexvirus obtained from patchouli, Pogostemon clabin, collected in São Paulo, Brazil in 1992. The plants showed mosaic and were infected by a potyvirus and a potexvirus. The potexvirus had a host range limited to Amaranthaceae, Solanaceae and Labiatae and was named Patchouli virus X (PatVX). PatVX was not transmitted by scissors pruning, in tobacco seeds or by Myzus nicotinae. The virus was purified and a specific antiserum with a titre great than 1:512 000 in dot‐ELISA was produced. The virus was serologically related to Papaya mosaic virus, Potato virus X, Viola mottle virus, White clover mosaic virus and Lily virus X. It had a coat protein of 21 071 ± 1 010 Mr. as determined by SDS‐PAGE. Immunolabelling tests demonstrated that fibrillar masses in the cytoplasm contain the coat protein. The presence of a dsRNA was detected in PatVX infected plants.