bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inheritance of resistance to groundnut rosette virus in groundnut (Arachis hypogaea L.)
Authors: NIGAM S. N. , BOCK K. R. 
Published: February 2008

SummaryA method of field screening groundnut seedlings for resistance to groundnut rosette virus (GRV), by means of which over 97% incidence was induced in rows of susceptible test plants, was developed at Chitedze Research Station in Malawi. Two GRV‐resistant Virginia cultivars (RG 1 and RMP 40) were crossed with three susceptible cultivars, one from each of the Spanish (JL 24), Valencia (ICGM 48) and Virginia (Mani Pintar) botanical groups. Twelve F1 reciprocal crosses and their F2 and backcross generations were produced and the material screened in nurseries in 1985/86 and 1986/87. Seedlings raised from plants which did not become infected in the field were inoculated in the glasshouse in order to eliminate susceptible escapees.The numbers of diseased and healthy individuals in each population were subjected to χ2 tests. In the majority of the F2 populations a good fit was obtained for a ratio of one resistant to 15 susceptible plants, a ratio to be expected if resistance to GRV were determined by a pair of independent complementary recessive genes. This was further supported by data from backcross generations.
The use of the polymerase chain reaction (PCR) for the detection of bean yellow mosaic virus in gladiolus
Authors: VUNSH RON , ROSNER ARIE , STEIN ADINA 
Published: February 2008

SummaryA method is described for the improved detection of bean yellow mosaic virus (BYMV) in gladioli leaves. Specific sequences of BYMV RNA, present in total RNA extracts of infected plants were detected following amplification by the polymerase chain reaction (PCR). The viral RNA was initially reverse‐transcribed into cDNA, then specific sequences were amplified by PCR using specific oligonucleotides as primers. Detectable amounts of virus RNA in BYMV‐infected plant tissue by PCR were approximately three to four orders of magnitude lower as compared with those detectable by ELISA and molecular hybridisation. Combining PCR with molecular hybridisation (using a 32P‐labelled transcript of viral sequences as a probe), further increased the sensitivity of this method to a gain of four to five orders of magnitude as compared with direct molecular hybridisation, and enabled the detection of up to single picogram quantities of the virus.
Further properties of wineberry latent virus and evidence for its possible involvement in calico disease
Authors: JONES A. T. , MITCHELL M. J. , McGAVIN W. J. , ROBERTS I. M. 
Published: February 2008

SummaryThe flexuous filamentous particles of wineberry latent virus (WLV) were found to measure 620. 12 nm and not 510. 12 nm as previously reported. Analysis of dsRNA from infected plants detected a major species of c. 5.7. 106 mol. wt and minor species of lower mol. wt. Purified virus particles formed a major and a minor buoyant density component in solutions of caesium salts with densities of 1.26 and 1.25 g cm‐3 in Cs2SO4 and 1.30 and 1.29 g cm‐3 in CsCl. The particles contained a single nucleic acid species, presumably single stranded RNA, and a single polypeptide of estimated mol. wt 2.78. 106 and 31 000 respectively. In indirect ELISA, purified particles of WLV and particles in plant sap failed to react specifically with antiserum to nine carlaviruses, 12 potexviruses, three capilloviruses or apple chlorotic leafspot closterovirus, nor was WLV found to react with several of these antisera in immunosorbent electron microscopy or immunoblots. In Marion and Olallie blackberry, WLV in mixture with raspberry bushy dwarf virus (RBDV), but not RBDV alone, induced veinal line‐pattern symptoms resembling those of calico disease reported from the USA.
Field trials using single potato plants as whole plots, with and without nematicide treatment, to assess tolerance of attack by Globodera rostochiensis
Authors: EVANS K. , RUSSELL M. D. 
Published: February 2008

SummaryIt is important to assess the tolerance of new potato cultivars with partial resistance to potato cyst nematode attack. The experiments described here are intended to quantify tolerance adequately using a minimum of resources. When test plants were spaced widely in the field trials it was also possible to estimate their resistance levels but standard plant spacing allowed roots of neighbouring plants to encroach on a test plant's root space and to interfere with attempts to assay resistance. Standard plant spacing did, however, give more realistic yields per plant and competition from neighbouring plants was standardised by surrounding each test plant by four identical guard plants (cv. Désirée). Regressions of yield on severity of nematode attack were drawn when nematode infestation varied naturally across the trial site or when different levels of attack were created by applying nematicide at a range of dose rates. Cara was the most tolerant cultivar tested, with a complete spectrum of tolerance shown by other cultivars/clones. Some clones with a high degree of resistance were intolerant and it is precisely these that this type of test seeks to identify.
Effect of seed depth on slug damage to winter wheat
Authors: GLEN D. M. , MILSOM N. F. , WILTSHIRE C. W. 
Published: February 2008

SummaryIn a field experiment drilled at two depths on three dates in autumn 1988, with or without methiocarb pellets broadcast on the soil surface immediately after drilling, 26% of seeds of winter wheat sown at c. 20 mm depth were killed by slugs compared with only 9% of seeds sown at c. 40 mm. The protection from slug damage provided by this additional 20 mm of depth was comparable with that provided by methiocarb pellets. The effects of seed depth and pellet application did not interact and were consistent on all drilling dates. Thus, fewest seeds and seedlings were killed where methiocarb pellets were broadcast on a seed‐bed with seeds sown at 40 mm depth. Intermediate damage was recorded where seeds were sown at 40 mm depth without pellets, or where pellets were broadcast on seeds sown at 20 mm depth. Most seeds and seedlings were killed where seeds were sown at 20 mm depth without pellets. Sublethal damage to seedlings was not affected by sowing depth but was reduced where pellets were broadcast immediately after sowing.
Observations on the distribution of leather jackets in Northern Ireland
Authors: BLACKSHAW R. P. 
Published: February 2008

SummaryA map of the geographic distribution of leather jackets across five counties of Northern Ireland was produced from annual survey data. Climatic data were used to develop a multiple regression model explaining variation in the mean annual survey population for the years 1970–1984. Predicted populations for 1985–1988 compared favourably with observed counts. Both negative binomial and Adès distributions were successfully fitted to the frequency distribution of leatherjacket field populations from 1969–1986. It is concluded that the distribution of populations in the Province is not random and factors influencing mean leatherjacket numbers differ from those reported for other regions. The multiple regression model is proposed as a substitute for an annual survey of leatherjacket populations in Northern Ireland and it is suggested that the Adès family of distributions may enable it to be extended to predict leatherjacket frequency distributions each year.
A comparison of vector population indices for forecasting barley yellow dwarf virus in autumn sown cereal crops
Authors: KENDALL D. A. , CHINN N. E. 
Published: February 2008

SummaryTwo approaches based on the concept of a vector population index are considered as possible deterministic elements for an empirical forecast of barley yellow dwarf virus (BYDV) in autumn sown cereals. The first, an aerial vector index, is a further elaboration of the infectivity index proposed by Plumb, Lennon & Gutteridge (1981), which assumes that virus damage is a function of the number of infective migrant alatae of the two main aphid vectors, Rhopalosiphum padi L. and Sitobion avenae F., integrated over time from crop planting or emergence. The new formulation, however, excludes holocyclic alate morphs (i.e. males and gynoparae) of the former species, which, although generally abundant in autumn, are nevertheless perceived as relatively unimportant virus vectors since they colonise only the alternative woody host, Prunus padus (the bird‐cherry tree). The second approach, a crop vector index, is a more fundamental departure which argues that field populations of viruliferous aphids, both alatae and apterae, which have already colonised cereals, may be a better criterion of potential virus spread than the density of aerial migrant vectors. This index retains a similar integral form, but evaluates crop exposure to BYDV as accumulated infectious aphid‐days. A method is described whereby this function can be derived from irregular or infrequent aphid samples in the crop. Both methods, unlike Plumb's (1976) original concept, produced indices which were significantly related to subsequent virus infection and yield loss in winter barley at Long Ashton (S.W. England, UK), 1978–1986. The best models were obtained with the crop vector index, fitted to observed virus infection by generalised linear regression using a complementary log‐log link function, or to observed yield loss by simple linear regression using a log transformation of yield (r = 0.84 in each case; compared with r‐values > 0.65 for the aerial vector index, and > 0.35 for Plumb's (1976) index). However, the residual errors and hence confidence limits of these fitted regressions were too large for predicting damage that was significantly less than a reasonable economic damage threshold for BYDV control.Analyses of the separate components of each index showed a good general relationship between aphid infectivity and the severity of crop infection, confirming the epidemiological importance of this factor. The functional expressions of aphid density, however, were not significant. This evident weakness in the models, and alternative approaches to BYDV forecasting are discussed.
Pre‐harvest retting of flax with glyphosate: effects of novel methods of spray application on penetration of the canopy and uniformity of deposition
Authors: HARVEY B. M. R. , WATSON S. , BAILIE J. E. , SAUNDERS A. , McMORDIE I. 
Published: February 2008

SummaryFour methods of spray application were compared in 1986 with the recommended method of glyphosate application for pre‐harvest retting of flax (Linum usitatissimum). Sampling individual plants immediately after application of glyphosate and dye demonstrated that spray penetration through the crop canopy, measured as dye deposition on the lower stem as a percentage of total deposition per plant, was the same for all methods of application. None of the methods of application improved the uniformity of dye deposition.The following year, effects of deseeding prior to spraying and of using an air‐assisted sprayer were investigated. Deseeding increased dye deposition on the lower stem but did not improve the efficacy of glyphosate. Application with an air‐assisted sprayer increased the proportion of spray deposited on the lower stem but not the absolute amount deposited or the efficacy of glyphosate. Dye deposition on individual plants varied greatly for all methods of application and, when glyphosate was applied using the same methods, undesiccated plants occurred in all plots.Considerable improvements in spray penetration and uniformity of spray deposition appear necessary for successful pre‐harvest retting of flax with glyphosate.
The influence of climatic conditions around the time of spraying isoproturon on the subsequent injury to barley
Authors: BLAIR A. M. , MARTIN T. D. 
Published: February 2008

SummaryWinter barley cv. Igri was grown in pots, either outside under cover, in a glasshouse or under controlled conditions and treated post‐emergence with isoproturon. There was a linear relationship between the subsequent weight of plants treated with 2.5 kg a.i./ha and either evaporation from a water surface between 2–7 days post spraying or cumulative temperature between sowing and spraying. The relationship between subsequent weight of plants treated to the foliage only with 5 kg a.i./ha and cumulative temperature between sowing and spraying varied between years 1984–86. The post spraying environment had the major influence on subsequent activity of isoproturon at 2.5 kg a.i./ha applied overall to barley under controlled conditions. There was a greater reduction in CO2 exchange in plants grown after treatment under high compared to low relative humidity. When isoproturon at 5 kg a.i./ha was applied to barley plants with wet foliage, plants were slower to recover their initial rate of photosynthesis when kept wet for 24 h as compared with 11 h or when allowed to dry after treatment. Photosynthesis was decreased to a lesser extent under the same post spray conditions by 2.5 than by 5 kg a.i./ha and reduction was greater and recovery of photosynthesis slower in plants grown inside compared to outside.
Physiological responses of mangoes cv. Kensington Pride to gamma irradiation treatment as affected by fruit maturity and ripeness
Authors: BOAG T. S. , JOHNSON G. I. , IZARD M. , MURRAY C. , FITZSIMMONS K. C. 
Published: February 2008

SummaryAn investigation was undertaken to examine responses of mangoes cv. Kensington Pride to irradiation treatment.Gamma irradiation of preclimacteric fruit increased fruit respiration immediately after treatment, delayed the time to attain the climacteric respiratory peak and reduced the magnitude of this peak rate. Fruit softening was unaffected whereas skin colour development was strongly inhibited by irradiation treatment. Inhibition of skin degreening was half‐maximal at a dose of 200 Gy. Exposure to ethylene failed to reverse this inhibition. Less mature fruit were more strongly affected by irradiation treatment. Fruit which were partially ripe and in their climacteric rise at time of treatment were largely unaffected by irradiation. These results are discussed in terms of the utility of irradiation technology for commercial disinfestation.
Components of resistance to the sorghum midge, Contarinia sorghicola
Authors: SHARMA H. C. , VIDYASAGAR P. , LEUSCHNER K. 
Published: February 2008

SummaryStudies were conducted on components of resistance to sorghum midge on four resistant (DJ 6514, AF 28, TAM 2566 and IS 15107) and two susceptible cultivars (CSH 1 and Swarna). Data were recorded on the numbers of eggs, larvae, emerged adults and grain damage in panicles of different genotypes infested with 60 midge females/panicle under no‐choice conditions. The size of floral parts (glume, lemma, palea, lodicule, stigma, style, ovary and anther), rate of grain development and tannin content of grain were measured. The lengths of glume gl and 82, lemma L1 and L2, palea, lodicule, anther, style and stigma were positively associated with susceptibility to sorghum midge. Rate of grain development (between 3rd and 7th day after anthesis) was negatively associated with susceptibility to sorghum. Tannin content of grain was also negatively correlated with midge susceptibility, although there were distinct exceptions (e.g. DJ 6514 is highly resistant bur has a low tannin content).
Development of a technique to study seedling emergence in response to moisture deficit in the field —The seed bed environment*
Authors: SOMAN P. 
Published: February 2008

SummaryThe ability of crops of sorghum (Sorghum bicolor (L.) Moench) to establish in farmers' fields depends largely on its capacity to germinate and emerge under limited soil moisture conditions. Studies on germination under moisture stress have been previously conducted using osmotic media which do not wholly reproduce the conditions of the seed bed in the field. Hence the need for a field screening technique. A line source irrigation system was used to provide five moisture regimes ranging from ‐0.08 MPa to ‐0.92 MPa. The drying rate of the soil and the soil temperature depended largely on incident radiation, and the relationship between the moisture content and daily soil temperature and daily radiation was consistant. Total porosity of the seed bed, derived from bulk density measurements and particle density ranged from 43.8% to 45.3%, which would allow sufficient aeration when as in the experiments conducted here, water content was low (> 0.14 g/g). Under these seed bed conditions the pattern of response of emergence to the moisture gradient was linear or curvilinear. Genotypic differences existed for emergence and its response to water level. The field method developed is useful for identifying genotypes able to germinate and emerge under conditions of low seed bed moisture.
The influence of seed quality and pregermination treatment on cauliflower and cabbage transplant production and field growth
Authors: FINCH‐SAVAGE W. E. , McKEE J. M. T. 
Published: February 2008

SummarySeedling emergence and subsequent growth from untreated seeds and selected‐germinated seeds which had been dried before sowing (low‐moisture‐content germinated (LMCG) seeds) were compared in cellular trays in a glasshouse and in the field following transplanting. Three seed lots of different quality of the same cultivar were used for cabbage and cauliflower. In all cases, seedling emergence was greater, earlier and more uniform from LMCG seed than that from untreated seeds. LMCG seed effectively eliminated the differences due to seed quality shown by untreated seeds at emergence suggesting an improvement in seed vigour as well as viability from the selection treatment. Higher quality seed and LMCG cauliflower seed led to larger curd weights and therefore an increase in marketable yield at harvest compared to that from lower quality seeds. However, differences in transplant uniformity due to seed quality and seed treatment had little impact of agronomic significance following transplanting.
Monitoring populations of the carrot fly, Psila rosae, with sticky and water traps
Authors: COLLIER ROSEMARY H. , FINCH S. , EMMETT B.J. , BLOOD‐SMYTH JENNIE 
Published: February 2008

SummaryThe relative, effectiveness of Rebell®, small cylinder, large cylinder, windmill and water traps, the five types of trap used currently for monitoring populations of the carrot fly, Psila rosae, was assessed in nine field experiments, three in south west Lancashire, four in the Fens (Suffolk, Norfolk, Cambridgeshire), one in East Suffolk and one at Wellesbourne, Warwickshire. Regression analysis of the numbers of flies caught on each type of trap against the numbers caught on the Rebell® trap indicated that each trap samples a constant proportion of the fly population relative to the other traps. Therefore, provided the fly population was sufficiently large for insects to be caught on the least effective traps, any of the five traps would monitor adequately fluctuations in carrot fly populations. However, the Rebell® trap caught 4–17 times as many flies/trap and 5–7 times as many flieshnit area of trap as any of the other traps tested.Operators considered the Rebell® trap to be the easiest to use. However, it was more expensive than any of the other traps tested.
Lipid metabolism of Pleurotus sajor caju
Authors: NAIR N. G. , HOLLEY M. P. , SONG C. H. , CHO K. Y. 
Published: February 2008

SummaryThe biosynthesis of lipids in the mycelium and sporophore of Pleurotus sajor caju was studied. Whereas in the mycelium the biosynthesis of lipids was directly primarily towards storage (e.g. tri‐acylglycerols), in the sporophore it was directed towards structural components (e.g. sterols). The incorporation of 14C precursors into non‐polar and polar lipid fractions was generally similar for 14C acetate, 14C palmitate, 14C oleate and 14C linoleate in the case of mycelium and sporophore. It appears that linoleic acid was utilised as a source of acetate for lipid biosynthesis in the sporophore. A significantly higher incorporation of label was seen in sporophore sterol than in mycelial sterol. Malate dehydrogenase activity increased in the mycelium grown in the presence of lipids. Lipase of P. sajor caju was inducive. The growth of P. sajor caju was enhanced by increased lipid utilisation. The implications of these results on commercial cultivation of this fungus are discussed.
Lettuce big‐vein virus: mechanical transmission and relationships to tobacco stunt virus
Authors: HUIJBERTS N. , BLYSTAD D. ‐R. , BOS L. 
Published: February 2008

SummaryBig‐vein diseased lettuce plants contained an agent that could consistently be transmitted mechanically to Chenopodium quinoa, in which it caused characteristic local lesions. Mechanical transmission was also possible to five other plant species including Nicotiana benthamiana, N. clevelandii and N. occidentalis, but not to lettuce. Symptoms in N. occidentalis were reminiscent of those of tobacco stunt disease. With zoospores of originally virus‐free Olpidium brassicae, subcultured on the roots of N. occidentalis‐P1, sap‐inoculated either from lettuce or via C. quinoa, the agent could be transferred back to lettuce in which characteristic symptoms of big‐vein were reproduced.Infectivity in sap at room temperature was reduced by half after 2 h, and was practically lost after one day. Thermal inactivation was considerable at 45°C and complete at 50°C. Most infectivity was lost at dilution 1:5, and the dilution end‐point was 1:10. The agent survived well in leaf material stored at ‐80°C, or in sap from leaves ground in buffer with DIECA and activated charcoal and freeze‐dried. Mechanical transmission required low dilution (1:2) in the buffer with charcoal, and chilling of materials and utensils.In lettuce, N. occidentalis‐P1 and C. quinoa, with all isolates tested but one, infection was always associated with the presence of rod‐shaped particles which in the literature have been associated with lettuce big‐vein, and are similar to those described for tobacco stunt. Results obtained corroborate the assumption that these particles are the virions of lettuce big‐vein virus. The virus also resembles tobacco stunt virus in mechanical transmissibility, instability in sap and symptoms on N. occidentalis.
Transmission of potato leafroll virus in relation to the honeydew excretion of Myzus persicae
Authors: HEUVEL J. F. J. M. VAN DEN , PETERS D. 
Published: February 2008

SummaryHoneydew excretion of single Myzus persicae nymphs on potato leafroll virus (PLVR)‐infected Physalis floridana was studied during the acquisition access period (AAP) in relation to the efficiency of virus transmission.With increasing length of the AAP, the percentage of nymphs that transmitted the virus increased. These nymphs produced significantly more honeydew droplets during the AAP on PLRV‐infected P. floridana plants than nymphs which failed to transmit the virus. However, the number of honeydew droplets excreted during the AAP by transmitting nymphs did not affect the length of the latency period. Nymphs which infected the first test plant after a short latency period produced a similar amount of honeydew during the AAP to those with a longer latency period.Honeydew excretion recorded on plants of varied age, showed that nymphs feeding on bottom leaves of infected plants produced more honeydew droplets than on comparable leaves of healthy plants. On infected plants, nymphs produced more honeydew droplets on bottom leaves with pronounced symptoms than on top leaves that hardly showed any symptom of PLRV infection.The concentration of viral antigen measured by ELISA was lower in top leaves than in bottom leaves of infected plants. Nevertheless, nymphs feeding on top leaves transmitted the virus more efficiently than those which used bottom leaves as virus source. When bottom leaves were used as a virus source, the percentage of viruliferous nymphs decreased with plant age. These results indicate that the availability of virus for acquisition by aphids declines with increasing plant age and symptom severity.