bluuebunny/crossref_metadata_2025_split huggingface dataset:
Responses of potato genotypes to drought. I. Expansion of individual leaves and osmotic adjustment
Authors: JEFFERIES R. A. 
Published: February 2008

SummaryThe expansion of individual leaves was examined in 19 genotypes of potato (Sofunum tuberosum L.) grown either with irrigation or droughted from the time of plant emergence. Drought reduced the thermal time from emergence to leaf appearance in 10 genotypes but had no significant effect in the other genotypes. In all the genotypes, final size of leaves was reduced by drought, but the magnitude of the effect differed significantly (P < 0.001) with genotype. In the droughted treatment, the final size of leaves was correlated (P < 0.001) with the maximum rate of leaf expansion suggesting that reductions in final size of leaves were the result of reduced expansion rate rather than of effects on the duration of expansion.Both the constant and the slope of the relation between leaf expansion rate and soil moisture deficit differed between genotypes. Osmotic adjustment was limited, maximally 0.16 MPa, and did not correlate with the ability to maintain leaf expansion with increasing soil moisture deficit.
Responses of potato genotypes to drought. II. Leaf area index, growth and yield
Authors: JEFFERIES R. A. , MACKERRON D. K. L. 
Published: February 2008

SummaryCanopy expansion, growth and yield were examined in 19 genotypes of potato (Solanurn tuberosum L.) grown either with irrigation or droughted from the time of plant emergence. In the irrigated treatment, genotypes differed both in the maximum leaf area index (Lai) achieved and in the duration the canopy was maintained. Drought reduced both the rate of canopy expansion and the maximum Lai achieved.In the droughted treatment, biomass production was correlated with leaf area duration. The relation between the effect of drought on the growth of individual leaves and biomass or yield is examined. It is concluded that selection for early leaf appearance combined with the ability to sustain leaf growth with increasing soil moisture deficit (SMD) would improve productivity in the presence of drought.
The rapid determination in controlled environments of parameters for predicting seedling growth rates in natural conditions
Authors: BREWSTER J. L. , SUTHERLAND R. A. 
Published: February 2008

SummaryParameters which characterise the response of seedling growth rate to temperature and mean daily radiant exposure were determined for cultivars of eight vegetable species and two ornamental bedding plant species using controlled environments. All species were grown for approximately four weeks in a series of four controlled environments consisting of factorial combinations of 20°C or 15°C with 7.78 or 0.98 MJ m‐2radiant exposure per day to photosynthetically active radiation. Four of the vegetable cultivars had been used previously in a study of growth in the glasshouse at different seasons. The parameters derived from controlled environments were used, with temperature and light measurements from the glasshouse, to predict seedling shoot growth in the glasshouse. These predictions accounted for 92% of the observed variance in log shoot dry weight in a series of glasshouse experiments involving thirteen combinations of species and sowing date, each grown at four plant densities and sampled on four occasions. Equivalent parameters derived previously from the glasshouse data themselves accounted for 92% of the variance in the same predictive exercise. Differences in base temperature for growth, the responsiveness of relative growth rate to daily radiant exposure (light), and the potential relative growth rate were apparent between species and were quantitatively characterised by the parameters. To determine these parameters for a cultivar requires the equivalent of one square metre of controlled environment growing area for approximately sixteen days. Such parameters could be applied for scheduling and management in crop production, particularly in transplant production.
Field evaluation of alpha‐chlorohydrin against the Indian mole rat: studies on toxic and antifertility effects
Authors: SAINI MANJIT S. , PARSHAD V. R. 
Published: February 2008

SummaryField acceptance and efficacy of a toxicant‐sterilant, alpha‐chlorohydrin (α‐CH), at its 0.5% concentration in bait were evaluated against rodents in sugarcane fields which harboured high populations of the Indian mole rat Bandicota bengalensis (Trap Index (TI) = 53.6 rats/100 traps/24 h) followed by that of the Indian bush rat Golunda ellioti (TI = 28.6) and soft‐furred field rat Rattus meltada (TI = 1.8). Acceptance of the α‐CH bait by rodents in the fields was evident from complete consumption of the offered bait at most of the baiting points. The treatment (72 h exposure to the poison bait) resulted in 63.7% to 82.9% rodent mortality. Survey of the mature sugarcane crop revealed that the percentage of rodent cut canes in the treated fields (7.6% to 16.2%) was significantly less than that of the reference fields (26.3%). Most of the surviving male B. bengalensis, captured after 15 days of the treatment, had developed sterility as revealed by the functional abnormalities in their testes and epid‐idymides. They showed decreased thickness of the seminiferous tubules, lower population of spermatogenic cells, cauda epididymal sperm concentration, live sperm and sperm mortality. A nonsignificant positive correlation between the testicular weight and sperm motility in males from treated fields indicated the effect of α‐CH at maturation level in the cauda epididymides. Overall, it was evident that a significant proportion of the surviving B. bengalensis had become permanently sterile as a consequence to the development of spermatocoeles in the caput epididymides and the remaining had significantly low numbers (< 30%) of motile sperm in their cauda epididymides which was, obviously, a handicap for successful fertilisation.
A review of white rust (Puccinia horiana Henn.) disease on chrysanthemum and the potential for its biological control with Verticillium lecanii (Zimm.) Viégas
Authors: WHIPPS J. M. 
Published: February 2008

SummaryThe biology, aetiology and epidemiology of Puccinia horiana, the cause of white rust disease of chrysanthemum (Chrysanthemum spp.) is reviewed in relation to current environmental, cultural and chemical methods for its control. Importantly, basidiospore release, germination and infection can take as little as 5 h at optimum r.h. (96%) and temperature (between 17–24°C). Recent developments using the fungus Verticillium lecanii for the control of insects on glasshouse‐grown all‐year‐round chrysanthemums rely upon the maintenance of r.h. during night periods in excess of 95%, thus predisposing plants to white rust attack. However, V. lecanii is unusual in that it can also parasitise spores and fruiting structures of a range of rust fungi including P. horiana. This mycoparasitic ability is also reviewed, and against this background, the potential for an integrated insect and white rust control programme on all‐year‐round chrysanthemums is assessed.
The influence of black bean aphid, Aphis fabae Scop., and its honeydew on leaf growth and dry matter production of sugar beet
Authors: HUREJ MICHAL , WERF WOPKE VAN DER 
Published: February 2008

Summary A. fabae populations, started at the 3–4 leaf‐stage of sugar beet in the glasshouse and peaking at 3000 individuals per plant, reduced leaf area by 64% at the 14 leaf‐stage. The size of the heavily‐infested leaves number 5 to 10 was reduced by 80% or more. The rate of leaf growth regained normal values after the aphid populations collapsed, but the infested plants did not make up for the decrease in leaf area production that had been incurred during the infestation. Total dry matter production over a period of 15 weeks was reduced by 47%. Honeydew had no effect on leaf size or dry matter production. Sugar beet plants in the field became infested with A. fabae at the 2–3, 4–5 and 6–8 leaf stages. Maximum populations of 800, 2100 and 2200 aphids per plant were recorded, respectively. The pertinent reductions in leaf area were 91%, 67% and 34% at the 10–12 leaf‐stage and 79%, 65% and 14% at harvest while the total dry matter produced was reduced by 91%, 79% and 16%. Neighbouring plants of the early‐infested sugar beet plants gained significantly higher weights than control plants. Honeydew had no effect on leaf area or dry matter production. The consequences of these results for our understanding of Aphis fabae injury in sugar beet and aphid control in the field are discussed.
Sexual generation and overwintering of the peach leaf curling aphid Brachycaudus helichrysi (Kalt.) in Himachal Pradesh, India
Authors: GUPTA P. R. , THAKUR J. R. 
Published: February 2008

SummaryAutumn migrants preferred to settle on the dorsal leaf surface of peach with gynoparae being more numerous than alate males. These return migrants on peach were similar to those described by others except for a comparatively smaller processus terminalis. Among the oviparae with metatibial pseudosensoria. most (62.5%) had six antennal subdivisions; 25% possessed five antennal subdivisions and half of these were parasitised. Oviparae were bigger than those previously described on plum/damson but their processus terminalis was comparatively shorter. Ultimate instar nymphs were without pseudosensoria and had 5–seg‐mented antennae, the VI segment being cleaved from the meriston during the final moult. Alate males mated with the oviparae, mating duration being 3 to 6 min. Oviparae contained, at the most, two well developed eggs at one time, and normally deposited eggs singly during November‐December. Most eggs hatched within 20–28 days but those laid in December during colder weather took up to 50 days to hatch. By midJanuary most eggs had hatched. Fundatrix developmental rate was dependent on sap‐flow. Overwintering occurred as the fundatrix.
Field tests of bacteria and soil‐applied fungicides as control agents for take‐all in winter wheat
Authors: HORNBY D. , BATEMAN G. L. , PAYNE R. W. , BROWN M. E. , HENDEN D. R. , CAMPBELL R. 
Published: February 2008

SummaryPutative biological and chemical treatments for controlling take‐all were used in each of three consecutive years at two locations where winter wheat crops were grown in naturally‐infested fields. The chemical treatments more often decreased take‐all than the biological treatments, but no treatment consistently and significantly decreased take‐all, nor did any cause a significant increase in yield.An isolate of Bacillus cereus var. mycoides and one of B. pumilis, applied as soil drenches in autumn or spring, or in the seed furrows, were usually ineffective. Of the few significant effects on disease, half were associated with increases and half with decreases, and most occurred in April and did not persist to late June. Two strains of Pseudomonas pluorescens applied to the seed were ineffective.The fungicide benomyl, applied as a drench in autumn and spring at 20 kg/ha was ineffective, while nuarimol, applied as a drench in autumn at 2 kg/ha was sometimes effective. Nuarimol incorporated into the seed bed at 2 kg/ha was the most effective treatment.In analyses using a functional relationship model for data from treated and untreated plots 12% of 176 data sets for biological treatments, 38% of 96 data sets for chemical treatments and 81% of 16 data sets for combined treatments showed increasing efficiency of the treatment with increasing disease intensity. These findings also demonstrate an additional advantage of the experimental design, namely that treatments are tested at different disease intensity levels within fields.
The detection of single‐stranded RNA in an isometric virus‐like particle from Shiitake mushroom [Lentinus edodes (Berk.) Sing.]
Authors: XUEREN SHEN , MINGJIE CHEN , JUYING SHEN , YANGJIE PAN , ZUXUN GONG 
Published: February 2008

SummaryIsometric virus‐like particles (VLPs) with diameter of approximately 34 nm containing ss‐RNA were purified from abnormal mycelium of Shiitake mushroom, Lentinus edodes (Berk.) Sing. SDS‐polyacrylamide gel elec‐trophoresis demonstrated that the virions contain a single capsid polypeptide with molecular weight of about 22 000 daltons. The nucleic acid extract from purified VLPs preparations showed only one band with a size of approximately 7.3 kilobases. The susceptibility to RNase 1 and S1 digestions, resistance to DNase and thermal denaturation behaviour of the viral genome indicated that it is a single‐stranded RNA. To our knowledge, isometric single‐stranded RNA VLPs isolated from Shiitake mushroom mycelia have not been reported before.
The virobacterial agglutination test as a rapid means of detecting cocoa swollen shoot virus
Authors: HUGHES J. d'A. , OLLENNU L. A. 
Published: February 2008

SummaryThe virobacterial agglutination (VBA) test was developed as a means of detection of cocoa swollen shoot virus (CSSV). Identification of CSSV‐infected Theobroma cacao in the field has only been possible by visual examination of symptoms, by virus transmission using mealybugs and by grafting to induce symptom expression in Amelonado cocoa seedlings. Detection of latent infection has not been possible even using enzyme‐linked immunosorbent assays (ELISA). The VBA test successfully detected CSSV in infected sap diluted to 1/2560. Antisera to a range of mild and severe CSSV isolates were tested, and the results suggest a close relationship between seven isolates (1A, Bosomtwi, Bosomuoso, Nkrankwanta, Nsaba, Seidi‐Nkawie and SS365B) while the mild isolate N1 appears to be less closely related. The VBA test was compared with both direct and indirect ELISA in the field. Only VBA detected all the cocoa trees which were known to be infected and additionally identified infection in many symp‐tomless trees.
Monoclonal antibodies specific for potato mop‐top virus, and some properties of the coat protein
Authors: TORRANCE L. , COWAN G. H. , PEREIRA L. G. 
Published: February 2008

SummaryA method was devised which gave consistent yields (1–2 mg/kg leaves) of potato mop‐top furovirus (PMTV) particles. Monoclonal antibodies (MAbs) were produced and some properties of 10 of them were studied. Four MAbs readily detected PMTV isolates from six countries in Northern Europe and Japan when the isolates were trapped with polyclonal antibody; and diagnostic tests based solely on MAbs (SCR 68 to coat plates and biotin‐ or enzyme‐labelled SCR 69 to detect trapped virus) were devised. The pattern of reactions of the MAbs in ELISA and immunoblots suggested that they react with at least five different epitopes.PMTV coat protein preparations were analysed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS‐PAGE) and immunoblotting. Three bands of 23.9 kd, 21.5 kd and 20.5 kd were visible in silver‐stained gels and all three reacted with PMTV specific MAbs. The relative amounts of the three bands varied between different virus preparations, but the 21.5 kd band was usually the most abundant. The three bands were probably not produced by anomalous behaviour in SDS‐PAGE. Moreover PMTV protein was readily degraded by trypsin treatment giving a band of 20.5 kd. Therefore the results suggest that PMTV coat protein sub‐units are sensitive to degradation by plant proteases. At least two degraded forms were found when purified preparations were analysed by SDS‐PAGE, and the undegraded protein was estimated to be 23.9 kd.The PMTV MAbs did not react in immunoblots with SDS‐treated coat protein preparations of beet necrotic yellow vein furovirus or Indian peanut clump furovirus.
Predation of annual grass weed seeds in arable field margins
Authors: POVEY F. D. , SMITH H. , WATT T. A. 
Published: February 2008

SummarySeeds of three species of annual grass weeds (Alopecurus myosuroides, Avena fatua and Bromus sterilis) were placed in field margins around arable fields in a randomised block split‐plot design experiment. The field margin vegetation was either sown or naturally regenerated and either cut or uncut. The seeds were either placed in cages designed to exclude small mammals and birds or were uncaged. The proportion of seeds removed was monitored on 10 occasions and mean seed loss was analysed.In general, a greater proportion of weed seeds was removed from uncaged trays in uncut swards, suggesting predation by small mammals, which inhabit tall grass. This effect was mainly due to removal of seeds of the two large‐seeded species (A. fatua and B. sterilis), with A. fatua being especially favoured.It is therefore likely that small mammals play a role in the population dynamics of major crop weeds by feeding on their seeds in field margins, especially when these are dense and uncut.
Fenoxycarb, a fairly new Insect Growth Regulato: review of its effects on insects
Authors: GRENIER SIMON , GRENIER ANNE‐MARIE 
Published: February 2008

SummaryTo reduce the impact of pesticides, new more selective chemicals need to be developed. Insect Growth Regulators such as Juvenile Hormone Analogues seem promising because of their specific mode of action on insects and their lower toxicity against Vertebrates than conventional insecticides. Nevertheless they remain toxic compounds. Fenoxycarb, a non neurotoxic carbamate shows a high JH activity, but also has other non JH specific effects. Effects of fenoxycarb on different pest and non‐target insects were reviewed from nearly 200 scientific papers dealing with this chemical used as insecticide.
Competitive interaction between strains of Verticillium lecanii on two insect hosts
Authors: CHANDLER D. , HEALE J. B. , GILLESPIE A. T. 
Published: February 2008

SummaryDifferences were observed in the pathogenicities of two strains of Verticillium lecanii (strain numbers 1.72 and 19.79) to the whitefly Trialeurodes uaporariorum and the aphid Macrosiphoniella sanborni. The mean pathogenicity of a mixture of the two strains was intermediate to that of the individual strains, attributable to a competitive interaction during infection. Differences between strains were observed in the production of conidia in vitro and on host insect cadavers. When hosts were infected with the dual‐strain suspension, conidia of strain 19.79 only were recovered from T. vaporariorum whereas conidia from both strains were recovered from M. sanborni.
The induction of systemic resistance in barley to powdery mildew infection using salicylates and various phenolic acids
Authors: WALTERS D. R. , MITCHELL A. F. , HAMPSON J. , McPHERSON A. 
Published: February 2008

SummaryTreatment of the first leaves of barley seedlings with either 5, 10, 15 or 20 mM salicylic acid, sodium salicylate or acetylsalicylic acid resulted in significant reductions in powdery mildew infection on the upper, second leaves. In general, the greatest reduction in mildew infection on the second leaves was obtained by spraying the first leaves with a 15 mM concentration of the compounds. Although the largest reduction in mildew infection of the upper leaves was obtained when the compounds were applied to the first leaves 1–2 days before inoculation, very substantial reductions in infection were still obtained if the first leaves were treated 12 days before inoculation. The three compounds had little direct effect on mildew infection. When 14C‐salicylic acid was fed to first leaves of barley seedlings, uptake was rapid and increased with time. Within 6 h, 0.2% of the salicylic acid appeared in the second leaf and by 24 h after feeding, this had increased to 1.4% (1.1 μmol salicylic acid g‐1 fresh wt).The application of various phenolic acids to first leaves also led to reductions in mildew infection on the second leaves. In particular, treatment of the first leaves with 1 mM vanillic acid, isovanillic acid or syringic acid, reduced mildew infection of the second leaves by 81–87%.
Identification and classification of a resistance breaking strain of barley yellow mosaic virus
Authors: BENDIEK J. , DAVIDSON A. D. , SCHULZE S. C. , SCHELL J. , STEINBISS H.‐H. 
Published: February 2008

SummaryA “resistance breaking” isolate of barley yellow mosaic virus‐2 (BaYMV‐2) was cloned as a cDNA and characterised. Restriction mapping and comparison with a German and a Japanese isolate of BaYMV (BaYMV‐G and BaYMV‐J) revealed a high level of restriction site conservation for RNAl and the majority of RNA2. However, in a box of approximately 600 nucleotides located on RNA2, striking differences in the restriction pattern could be identified. The nucleotide sequence of this box, as well as of the 3‘‐terminal region of RNA1 including the coat protein coding region, and the deduced amino acid sequences were analysed. Identity at the amino acid level was between 99.3% and 92.3% in comparison with the corresponding sequences of BaYMV‐G and BaYMV‐J, suggesting that BaYMV‐2 is closely related to BaYMV. Consequently, the classification of BaYMV‐2 as a “resistance breaking” strain of BaYMV is justified.
Effects of cereal borders, admixture with cereals and plant density on the spread of bean yellow mosaic potyvirus into narrow‐leafed lupins (Lupinus angustifolius)
Authors: JONES R. A. C. 
Published: February 2008

SummaryIn studies of virus control measures, field experiments in 1987–1991 investigated the effects of cereal and fallow borders, admixture with cereals and plant density on spread of bean yellow mosaic potyvirus (BYMV) from pastures dominated by subterranean clover (Trifolium subterraneum) into plots of narrow‐leafed lupins (Lupinus angustifolius). Virus spread was mainly monocyclic because BYMV killed infected lupin plants and between systemic movement and death there was only a brief period for BYMV acquisition and transmission to other plants by vector aphids. In plots with cereal borders, the rate and extent of BYMV spread into the lupins was decreased; at final assessment the numbers of infected plants were 43–60% less than in plots with fallow borders. Admixture with cereals also decreased the rate and extent of BYMV spread into lupin plots, numbers of infected plants being decreased by 76–96% at the time of final assessment. When lupins were sown at different seeding rates to generate a range of plant densities and weeds were removed, high densities decreased BYMV infection. The higher incidences of BYMV infection in sparse stands were attributed partly to smaller plant numbers and partly to incoming viruliferous vector aphids being more attracted to plants with bare earth around them, than to a plant canopy. BYMV infection decreased grain yield of samples from infected lupin plants by 94–100%. In plots with 34% infection and sparse stands, grain yield was decreased by about one third.Plotted progress curves for the accumulated numbers of alate aphids of the BYMV vector species Acyrthosiphon kondoi and Myzus persicae resembled those for numbers of BYMV infected plants in 1990, but in 1991 only the curve plotted for M. persicae did so. There was a 2 week delay between the curves for aphid numbers and virus counts which reflected the time taken for obvious systemic necrotic symptoms to develop in lupins.
Long‐term recovery of bracken (Pteridium aquilinum (L.) Kuhn) after asulam spraying
Authors: PAKEMAN R. J. , MARRS R. H. 
Published: February 2008

SummaryThis paper investigates the effects of a single asulam application, sprayed from the air, on the rhizome biomass, bud density, fronds and carbohydrate reserves of bracken (Pteridium aquilinum (L.) Kuhn) using a time sequence approach. Regression models were used to investigate how these characteristics varied with time after spraying, and were used, where appropriate, to calculate the time taken for full recovery after treatment. Frond density and biomass recovered in approximately eight years, bud numbers in seven, but rhizome biomass and total carbohydrate reserves required 10 to 12 years to recover. The consequences of these results are compared with predictions from a computer model and discussed in relation to the best timing of re‐treatment and the management needed for long term control.