bluuebunny/crossref_metadata_2025_split huggingface dataset:
Causes of uneven desiccation of flax by glyphosate: poor penetration of the canopy and variable spray deposition
Authors: HARVEY B. M. R. , CROTHERS S. H. 
Published: February 2008

SUMMARYFlax (Linum usitatissimum) cv. Hera was grown at densities of c. 2000, 1500 and 1000 plants m‐2sprayed with glyphosate (1·44 kg a.e. ha‐1) and red dye (1·5%).Dye deposition was measured and the mean total was 402, 503 and 602 μg per plant or 691, 761 and 761 μg g‐1DW for high, intermediate and low densities respectively. Variation between plants was large and significant differences were found only in deposition on the lower stem, this being about two‐fold higher for plants grown at 1000 m‐2than 2000 m‐2. However spray penetration through the crop canopy was poor and only c. 4% of the total deposit was intercepted by the lower stem. There was no detectable dye deposition on the lower stem of some plants in stands of all densities.The minimum deposits of glyphosate required for desiccation were assessed by applying precise doses, using a microsyringe, to plants grown under controlled environmental conditions. A total dose of 40 μg applied to the capsules, the upper stem plus leaves and the lower stem in the approximate ratio found for dye deposition on field grown plants, was required for successful desiccation. The minimum amount of glyphosate deposited in the field experiment, calculated assuming a linear relationship between dye and glyphosate deposition, was only 5 μg per plant.Position of application was also important. Application of 6 μg glyphosate to the lower stem caused desiccation of the whole plant whereas in applications to the upper stem and leaves 64 μg was required to have a similar effect.These experiments indicate that uneven desiccation of flax crops can be accounted for by both lack of uniformity of spray deposition and poor penetration of spray through the canopy to the lower stem, where glyphosate would be most active.
A glasshouse test to assess the sensitivity of potato cultivars to tobacco rattle virus
Authors: DALE M. F. B. , SOLOMON R. M. 
Published: February 2008

SUMMARYThe sensitivity to tobacco rattle virus of nine potato cultivars and 24 potato clones from the potato breeding programme at SCRI was assessed in a glasshouse pot test and in field trials for two consecutive years. The results and analyses presented indicate that the pot test gives an accurate and reliable estimate of sensitivity to tobacco rattle virus. Methods of assessing severity of expression of disease symptoms were examined. The advantages of such a glasshouse pot test and its application are discussed.
Prediction of the coefficient of variation of carrot embryo length from a germination test
Authors: GRAY D. , GENT LOUISE J. 
Published: February 2008

SUMMARYThe value of the International Seed Testing Association (ISTA) germination test in estimating levels of variation in embryo length between carrot seed lots was examined.For the two groups of seed lots used, the coefficient of variation (c.v.) of embryo length ranged from 16 to 50%. The c.v. of embryo length was negatively correlated with the numbers of normal seedlings counted after 7 days of germination at 20°C, rs= ‐ 0·72 D.F. 12 and ‐ 0·82, D.F. 15 for the two groups of seed lots used. Provided the relationship between these two characters is established for each laboratory, it is likely to be useful in identifying seed lots of potentially low c.v. of embryo length.
Quantitative and qualitative aspects in the production of a nuclear polyhedrosis virus in Spodoptera exigua larvae
Authors: SMITS P. H. , VLAK J. M. 
Published: February 2008

SUMMARY Spodoptera exigua nuclear polyhedrosis virus was produced in late fourth instar S. exigua larvae, reared on semi‐artificial diet. A maximum amount of virus, 1–2 × 109 polyhedra/larva, was produced in individually‐reared larvae after 7 days of incubation, with an inoculum of 7–5 × 104 polyhedra/cm2 diet surface.Virus yield was slightly reduced to 9 × 108 polyhedra/larva when production was carried out in groups of 400 and 600 larvae per container. Biological activity of virus harvested from living larvae and from dead cadavers was similar. Microbial contaminants, predominantly bacteria, in the virus product numbered 1–6% of the number of polyhedra. Tests for the presence of vertebrate‐pathogenic bacteria in the virus product were all negative.
Soybean leaf pubescence affects aphid vector transmission and field spread of soybean mosaic virus
Authors: GUNASINGHE U. B. , IRWIN M. E. , KAMPMEIER G. E. 
Published: February 2008

SUMMARYA study was undertaken to determine the influence of trichome density on the spread of non‐persistently transmitted plant viruses by aphid vectors. A system using soybean plants and soybean mosaic virus (SMV) tested the hypothesis that greater leaf trichome density inhibits probing activity of vector species, leading to reduced virus spread and retarded virus epidemics under field conditions.Probing activity of three important aphid vectors of SMV, Myzus persicae, Rhopalosiphum maidis, and Aphis citricola, was affected by the density of soybean leaf trichomes. Less pubescent and glabrous isolines elicited greater probing activity than did densely pubescent isolines. Among the parameters considered, probe duration was found to be species specific, whereas the following traits were consistent among species for the denser isolines: reduced numbers of probes, greater length of time to first probe, and less time spent probing. Laboratory transmission of soybean mosaic virus was reduced in the more densely pubescent isolines by the vector species tested.Field spread of SMV was negatively correlated with density of pubescence. In our system, we found that denser leaf pubescence retards field epidemics of non‐persistently transmitted plant viruses.
Reactions of white cabbage (Brassica oleracea var. capitata) to four different strains of turnip mosaic virus
Authors: WALKEY D. G. A. , PINK D. A. C. 
Published: February 2008

SUMMARYTuMV strains isolated in the UK, Germany, Denmark and Greece have been shown to be biologically distinct by host range studies. The effects of the four strains on symptoms, yield and storage performance of four cultivars of white cabbage were assessed in gauze house experiments. Three of the cultivars, Decema Extra, Vitala and Winter White III, were known to have high levels of resistance to the UK strain and the fourth, cv. Polinius, is known to be highly susceptible. The resistance to the UK strain previously observed in the three ‘resistant cultivars’ was generally effective against the other three strains; however, the level of resistance was virus strain dependent and variable for the symptoms of external necrosis, internal necrosis and yield depression. The UK strain caused the highest level of external necrosis and the German strain the highest internal necrosis. These two strains generally caused greater yield reductions than the Danish or Greek strains. Virus infection had no effect upon the incidence of the pepper‐spot necrosis disorder. Breeding strategies for handling the observed resistance are discussed.
Purification and some properties of oat golden stripe virus
Authors: ADAMS M. J. , JONES P. , SWABY A. G. 
Published: February 2008

SUMMARYOat golden stripe virus (OGSV) was maintained in oats by mechanical inoculation and purified by extraction of leaves in borate buffer, two cycles of centrifugation through sucrose cushions and isopycnic centrifugation in CsCl. An antiserum with a titre of 1/1024 in precipitin tests was prepared. Particle length distribution was bimodal with median values, respectively, of 150 and 300 nm from dip preparations. Measurements from immunosorbent electron microscopy (ISEM) and purified preparations showed that the particles had partially degraded during these procedures. The virus sedimented as two components of 168 S and 218 S and had a buoyant density of 1321 g cm‐3.Four isolates of OGSV reacted with the antiserum. Antiserum to members and possible members of the furovirus group were tested in ISEM decoration tests and in ELISA. OGSV was related to soil‐borne wheat mosaic virus but not to beet necrotic yellow vein virus, hypochoeris mosaic virus or potato mop‐top virus.
Ourmia melon virus, a virus from Iran with novel properties
Authors: LISA VITTORIA , MILNE R. G. , ACCOTTO G. P. , BOCCARDO G. , CACIAGLI P. , PARVIZY R. 
Published: February 2008

SUMMARYA virus associated with a mosaic disease in melons in the Ourmia district in northern Iran was mechanically transmissible to a wide range of test plants but was not transmitted using aphids, the whitefly Trialeurodes vaporariorum or the mite Tetranychus urticae. Its rather stable particles somewhat resembled those of both geminiviruses and alfalfa mosaic virus; they were 18·5 nm in mean width, parallel‐sided, and of several discrete lengths, 30 nm and 37 nm being the shortest and commonest lengths. Both ends of all particles were sharply triangular in profile. The particles contained linear single‐stranded RNA of three sizes, estimated as 0·91,0·35 and 0·32, all × 106 molecular weight, and two coat proteins of 26·3 and 23·3 × 103 estimated molecular weight. The virus, named Ourmia melon virus, appears to be the first described representative of a new virus group.
Relationship between inoculum density and vector phenology on the incidence of potato virus Y in tobacco
Authors: GRAY STEWART M. , LAMPERT E. P. 
Published: February 2008

SUMMARYThe epidemiology of potato virus Y (PVY) in the tobacco crop, Nicotiana tabacum, was examined in the context of the seasonal abundance of aphid vectors, rate of disease progress, and disease gradient from a known virus source. The spring potato crop, Solanum tuberosum, was suspected of being the main source of inoculum; therefore, varying numbers of infected potato plants were used as the inoculum source in different test plots.A 3‐wk lag phase was present in all disease progress curves prior to an exponential increase in disease incidence. The relatively low numbers of aphid vectors, primarily transient species, alighting on the crop during the lag phase were responsible for the primary spread of PVY from potato to tobacco. The arrival of large numbers of colonising aphid vectors, Myzus persicae, presumably from the harvested potatoes, coincided with the exponential increase in PVY incidence in tobacco.The initial number of potato plants infected with PVY was positively correlated with the final disease incidence, rate of disease progress, and the magnitude of radial dispersion of PVY into the tobacco. Aphid vector pressure was not a significant variable in the differences in spatial and temporal characteristics of PVY epidemics among test plots.
Shelf‐life of stored asparagus is strongly related to post‐harvest accumulated heat units
Authors: KING GRAEME A. , HENDERSON KATE G. , LILL ROSS E. 
Published: February 2008

SUMMARYThe effect of delay between harvest and hydrocooling, and of regimes of simulated air transport temperatures, on shelf‐life of fresh asparagus were quantified. Shelf‐life was strongly negatively correlated with the accumulated heat units experienced between harvest and post‐transport handling. A 2‐h delay in hydrocooling after harvest was similar to a 0.5°C higher temperature during a 2‐day transit period in effect on shelf‐life. It is essential for maximum shelf‐life that asparagus be kept cold from the completion of hydrocooling until sale.
Gibberellin, daylength and temperature effects on floral and vegetative development in white clover
Authors: NORRIS I. B. 
Published: February 2008

SUMMARYThe effects of gibberellin A3 (GA3) application on five white clover populations was assessed in both glasshouse and controlled environments. Daylength, temperature and GA3 interactions were also examined.Gibberellin A3 did not induce vegetative plants to flower when daylength and temperature requirements were not met. In flowering plants, GA3 increased the number of reproductive buds per stolon and peduncle length, but did not affect other floral characters.Gibberellin A3 depressed total stolon numbers, but increased the number of nodes per stolon, internode length, leaf area and petiole length.
The effect of Drechslera teres seed infection on spring barley seedling growth
Authors: DEADMAN M. L. , COOKE B. M. 
Published: February 2008

SUMMARYBarley seedlings (cv. Beatrice) emerging from seed infected with Drechslera teres were sorted into healthy seedlings, those with leaf sheath lesions and those with leaf blade lesions. Leaf area, plant height and total weight were reduced relative to healthy plants; leaf emergence also appeared to be delayed.
Initiation at the flowering stage of postharvest Botrytis stem‐end rot in normal and non‐ripening tomato fruits
Authors: LAVY‐MEIR GILA , BARKAI‐GOLAN RIVKA , KOPELIOVITCH E. 
Published: February 2008

SUMMARYFlowers of a normal tomato cultivar and of the two non‐ripening mutants rin and nor, were sprayed with a Botrytis cinerea spore suspension. Stem‐end infection developed in 84–100% of the harvested fruits of these sprayed flowers when held in high r.h. In both nor and rin fruits, rot development remained restricted to the stem‐end area and fruit shoulders, whereas in the normal fruit decay spread rapidly from the stem‐end over the entire fruit. Spraying the flowers with iprodione prior to spore inoculation resulted in decreased incidence of decay and suppressed hyphal growth and sporulation in all types of fruits. The results indicate that floral organs serve as a pathway for B. cinerea stem‐end initiation in both the normal and the mutant fruit and suggest that this mode of penetration is not related to the marked resistance to infection attributed to the mutant fruits.
The inhibitory effects of the molluscicide metaldehyde on feeding, locomotion and faecal elimination of three pest species of terrestrial slug
Authors: WEDGWOOD MARILYN A. , BAILEY STUART E. R. 
Published: February 2008

SUMMARYSingle meals on maize flour pellets containing 0, 0·5, 1, 2, 4, 6, and 8% metaldehyde were analysed in Arion hortensis (agg), Deroceras reticulatum and Deroceras caruanae, by attaching the pellets to a mechanical transducer from which signals were ultimately fed into a BBC microcomputer for on‐line analysis. Post‐feeding tests were used to investigate toxic effects of metaldehyde and the recovery of slugs was examined daily for 7 days. Bite rates were slightly lower and more irregular on metaldehyde meals especially in A. hortensis. The meal length and number of bites per meal were markedly inhibited by metaldehyde and inversely proportional to the concentration. The size of the bites was also reduced, by about 30%, in meals on 6% pellets compared with 0%. Clear symptoms of poisoning became evident during the meal or normally in the 16‐min test period immediately afterwards. In these tests slugs which fed on metaldehyde pellets showed a disruption of their ability to right themselves (after being placed on their side), less activity and a reduced probability of accepting a ‘dummy’ pellet containing no metaldehyde. It is hypothesised that feeding is prematurely terminated primarily because of the toxic effects of the metaldehyde and that aversion also acts to terminate the meal early, by decreasing the probability of continuing to feed as the meal proceeds. At higher concentrations of metaldehyde aversion may be more important than the toxic effects in ending the meal. Faecal elimination is delayed after metaldehyde meals and this contributes to mortality. The estimated lethal doses were about 0·2 mg/g body weight of slug in Deroceras spp. A. hortensis was less susceptible. To increase the likelihood of a lethal dose being ingested the inhibition of feeding needs to be overcome, at least partly, and the results presented indicate the need for a bait formulation which reduces the rate of absorption of the molluscicide from the gut.
Storage diseases of carrots in East Anglia 1978 – 82, and the effects of some pre‐ and post‐harvest factors
Authors: GEESON J. D. , BROWNE K. M. , EVERSON HELEN P. 
Published: February 2008

SUMMARYIn a survey of nine carrot crops stored during four seasons 1978 – 82, the major causes of wastage were spreading soft rots caused by Botrytis cinerea and Rhizoctonia carotae; rots caused by Sclerotinia sclerotiorum, Mycocentrospora acerina and Stemphylium radicinum were only of secondary importance. Storage weight losses were lower and roots remained turgid for up to 40 wk in an ice‐bank‐cooled store at 0·5 °C, 97 – 98% r.h., whereas carrots in conventionally‐cooled stores at 2 – 2.5 °C, 90 – 95% r.h. became flaccid after a few months. In some crops, losses due to fungal spoilage were also lower in the ice‐bank store. In two seasons' losses, mostly due to B. cinerea, were similar in hand‐ and machine‐harvested roots; pre‐storage washing of carrots grown on mineral soils increased the incidence of Botrytis rots, and reduced rotting by R. carotae, but had no effect on spoilage of roots from peat soils. Post‐harvest fungicide treatment with benomyl or iprodione (0·5 g/litre a.i.) effectively reduced rotting by B. cinerea and S. sclerotiorum, but not by R. carotae. The recoveries of sound carrots after 23 – 29 wk storage were consistently highest (mostly > 80%) from fungicide‐dipped roots stored under ice‐bank conditions, but recoveries from all treatments were lower and more erratic after 35 – 40 wk because of increased fungal spoilage. The practical applications of long‐term ice‐bank storage of UK‐grown carrots are discussed.
Trialling techniques in the breeding and prediction of recombinant inbred lines in onions (Allium cepa)
Authors: WERNER C. P. , DOWKER B. D. , DeSOUZA D. C. , CROWTHER T. C. , HOROBIN J. F. , KEARSEY M. J. 
Published: February 2008

SUMMARYAn outline is given of a novel breeding scheme for onions to produce highly vigorous, good quality inbred lines adapted for autumn‐sowing in the UK. The scheme involves the production of advanced generation inbred lines in the absence of selection, by single seed descent, starting with 1500 F2 plants from a Japanese × European cross. Concurrently a genetical analysis designed to predict the range of recombinant inbred lines derivable from this cross has been conducted using triple test cross (TTC) and basic generation (BG) families. Four trials are described, the results of which are used to define trialling techniques for the TTC and BG material which enable genetical predictions to be applied to direct‐drilled onions at commercial spacings. The ranking of genotypes for important agronomic characters remains unchanged whether they are grown as transplanted spaced single plants or direct‐drilled, however interactions may occur if pre‐chitted seed is used.
Triple test cross predictions of the performance of recombinant inbred lines from a wide cross in onions (Allium cepa)
Authors: WERNER C. P. , DOWKER B. D. , DeSOUZA D. C. , SETTER A. P. , CROWTHER T. C. , HOROBIN J. F. 
Published: February 2008

SUMMARYIn conjunction with an onion breeding scheme to produce recombinant inbred lines from a wide cross genetical experiments were carried out to predict the likely outcome. Results are given of genetical predictions, obtained from two triple test cross experiments, of the expected performance of inbred lines derivable by single seed descent from a Japanese × Polish cross. For bulb maturity, c. 12% of the inbred lines are expected to be earlier than the earlier parent; for bulb hardness over 50% of the inbred lines are expected to exceed the better parent. For bulb weight, predictions from the basic model suggest 5–25% of the inbred lines may exceed the better parent, but when this model is modified to take account of the likely inbreeding depression in the open‐pollinated Japanese parent, only 0–2% of such high yielding inbred lines are expected. Other potential sources of bias which may affect the predictions are discussed.
Ontogenic variation in nitrogen assimilation, nodulation and nitrogen fixation in groundnut (Arachis hypogaea) genotypes*
Authors: DUTTA M. , RAO B. SRINIVASA , NAMBIAR P. T. C. , WILLIAMS J. H. , DART P. J. 
Published: February 2008

SUMMARYSeasonal pattern of acetylene reduction (AR) and shoot nitrogen accumulation was studied in nine groundnut cultivars. Shoot N accumulation by all the cultivars was maintained until shortly before maturity and it occurred faster over the reproductíve growth phase than over the earlier phases. In all cultivars plant AR (PAR) did not reflect this pattern of N accumulation, being greater over the vegetative and pod initiation phases. This suggests that the commonly observed low PAR values for groundnut over the reproductive growth phase may be the result of factors other than sink competition.There were significant interactions of cultivar with stage of crop growth for PAR, nodule mass, and specific nitrogenase activity (SNA). Virginia types generally showed better nodulation, higher N2‐fixing capacity (both PAR and SNA) than valencias, and significant differences were observed between cultivars within a botanical type.
A vertical band‐Dutch harrow technique for incorporating granular nematicides in soil to control potato cyst‐nematodes, Globodera rostochiensis and G. pallida
Authors: WHITEHEAD A. G. 
Published: February 2008

SUMMARYIn lightly infested silt loam, aldicarb at 3·3 kg ha‐1in 1985 or oxamyl at 4·5 kg ha‐1in 1986, applied to the top 12 – 15 cm of the soil by a 5 m wide Dutch harrow fitted with vertical band granule outlets 15 cm apart, increased yields of King Edward or Romano potatoes and effectively controlled increase of potato cyst‐nematodes. Carbofuran at 5 kg ha‐1in 1986 was less effective.This new vertical band‐Dutch harrow technique has the advantage over the vertical band‐rotary harrow technique in that lateral mixing of the vertical bands of granules is not required. It is especially useful for poorly structured soils, which will not tolerate powered harrowing, and could also prove beneficial on other soils of low organic matter content.
The effects of some commonly‐used foliar fungicides on Collembola in winter barley: laboratory and field studies
Authors: FRAMPTON G. K. 
Published: February 2008

SUMMARYFour commonly‐used cereal foliar fungicides were screened for their laboratory toxicity against the symphypleone collembolan, Sminthurinus aureus. A proportional hazards analysis of time‐survival curves following the fungicide treatments showed that carbendazim, propiconazole, pyrazophos and triadimenol significantly increased the laboratory mortality of S. aureus. The organophosphorus fungicide pyrazophos caused high levels of mortality of S. aureus in the laboratory so a field evaluation of the effects of this fungicide on a wider range of Collembola was undertaken in winter barley.Comparison of the effects of pyrazophos with those of the broad‐spectrum insecticide dimethoate in the field revealed both compounds to have similar activity against some Collembola. Of the 11 species caught only the four symphypleone species exhibited these effects but the numbers of three symphypleone species were reduced to zero 4 wk after treatment with pyrazophos. The effects of pyrazophos and dimethoate were, however, not detectable in individual species after 11 wk.