bluuebunny/crossref_metadata_2025_split huggingface dataset:
The susceptibility of barley cultivars to barley yellow mosaic virus (BaYMV) and its fungal vector, Polymyxa graminis
Authors: ADAMS M. J. , SWABY A. G. , MACFARLANE I. 
Published: February 2008

SUMMARYIn glasshouse experiments, barley seedlings were inoculated with barley yellow mosaic virus (BaYMV) either mechanically or by using zoospores or cystosori of a viruliferous isolate of the vector, Polymyxa graminis, maintained on barley in sand culture.Experiments using mechanical inoculation showed that seedlings became more resistant with age. Consistent cultivar differences were obtained: cvs Maris Otter and Halcyon were very susceptible and cv. Athene seemed immune. Symptoms developed more rapidly at 23 than at 17 or 11 oC. After vector inoculation, symptoms developed more slowly than after mechanical inoculation but cultivar ranking was similar. Cultivars did not differ in susceptibility to the vector, as measured by zoospore production on their roots. Spring barley cultivars supported the growth of the vector which remained viruliferous and some showed symptoms although, in the field, symptoms do not appear on spring‐sown crops.
Yield in spring barley at contrasting sites in England and Scotland
Authors: ELLIS R. P. , BROWN J. 
Published: February 2008

SUMMARYThe yield and yield components of tall and short genotypes derived from the cross between two spring barley cultivars, Ark Royal and Golden Promise were examined. The genotypes were grown at two locations in England and two in Scotland. The highest yields were observed at two English sites (in East Anglia) rather than, as expected, in Scotland (East Lothian). Higher yield at the English sites was related to the greater means recorded for all the components of yield. The tall genotypes produced higher yields than the short genotypes, particularly at sites affected by drought. There were significant interactions between genotypes and environments for plot yield. Selection for increased yield would have been possible within either tall or short lines.
The effect of elevated temperatures and their duration on the incidence of hollow heart in pea seeds
Authors: HALLIGAN E. A. 
Published: February 2008

SUMMARYPlants of Pisum sativum cv. Pania were exposed to high temperature (35 oC day/25 oC night) at three stages in development. These were: (i) at process crop maturity, when the seed moisture content (m.c.) was 80%, i.e. about 10 days prior to pod wrinkle, (ii) at a seed m.c. of 70 to 80%, about the onset of pod wrinkle, and (iii) when the seed m.c. was 50 to 60%, 10 days after the onset of pod wrinkle. At each stage of development the high temperature treatment was imposed for 2,4,6, 8 or 10 days. Plants exposed to high temperature at seed m.c. of 70 to 80% produced seed with the highest incidence of hollow heart and at all stages of development the incidence increased with the length of exposure to the high temperature. Where plants at the development stage of pod wrinkle (seed m.c. 70–80%) were exposed to a range of temperature regimes for 5 days, over 20% of the seeds had hollow heart when the mean day/night temperature was 25 oC. Above a mean temperature of 25 oC, the percentage of affected seed increased with increasing day or night temperature. Over 80% of the seeds had hollow heart symptoms after 5 days exposure to a daily mean temperature of 32‐5 oC. The severity of symptom development was not related to the proportion of seeds with the disorder and, under laboratory conditions, seed germination was not affected.
Chemical control of wheat bulb fly (Delia coarctata) attacking winter wheat in Eastern England, 1969–1981
Authors: MASKELL F. E. , GAIR R. 
Published: February 2008

SUMMARYDry powder, liquid and microencapsulated formulations of organophosphate and synthetic pyrethroid insecticidal seed treatments were tested as possible alternatives to the standard organochlorine seed treatments for autumn‐sown wheat in mineral and organic soils heavily infested with wheat bulb fly eggs and (subsequently) larvae. Retention of insecticides on the seed coat varied from 40% to 120% of the target dose; it was usually good when microencapsulated formulations were used.Chlorfenvinphos, fonofos, isofenphos and triazophos, each applied at 2‐0 g a.i./kg seed, were phytotoxic, the symptoms varying from a slight delaying effect upon germination to an adverse effect upon grain yield. Chlorfenvinphos at 0–2 to 2‐0 g a.i./kg seed was consistently effective against wheat bulb fly larvae in both mineral and organic soils. Athidathion 0–8 g a.i./kg, carbophenothion 1–2 g a.i./kg, ethion 1–7 g a.i./kg and fonofos (microencapsulated formulations) at 1‐0 or 2‐0 g a.i./kg were also effective in mineral and organic soils. Of the synthetic pyrethroids tested as seed treatments, permethrin gave excellent results in mineral soils at 1‐0 g a.i./kg or in synergised formulations at 0–12 or 0–24 g a.i./kg but was disappointing in organic soils.In a single comparison of seed treatments applied to wheat sown early (14 October) and late (20 November), chlorfenvinphos was effective at both sowing dates whereas athidathion, ethion and pirimiphos‐ethyl gave better results in late‐sown wheat.A single trial compared deep with shallow sowing of treated seed. Most insecticides performed better on shallow‐sown wheat, but chlorfenvinphos was equally effective against the pest at both sowing depths.Most insecticides restricted the numbers of larvae entering host plants but had little or no subsequent effect upon larval survival within attacked shoots. Fonofos and isofenphos, and to a lesser extent chlorfenvinphos, seed treatments additionally killed many larvae within plant shoots.
Response of subterranean clover cultivars to root rot fungi
Authors: BARBETTI M. J. , WONG D. H. , SIVASITHAMPARAM K. , D'ANTUONO M. F. 
Published: February 2008

SUMMARYTwelve widely grown cultivars of subterranean clover (Trifolium subterraneum) were screened both under controlled environment conditions for their resistance to five fungi commonly associated with root rot and under field conditions for their resistance to natural root infections. All cultivars showed decreased seedling survival (particularly from Pythium irregulare and Rhizoctonia solani), tap and lateral root rot (particularly from Fusarium avenaceum, P. irregulare, and R. solani) and reduced plant size (particularly from R. solani and P. irregulare). Individual cultivars generally differed in their response to the five pathogens and for any one pathogen there was generally a range of cultivar susceptibilities. Cultivars with the best resistance to individual root pathogens were identified. The results for the five individual pathogens under controlled conditions only showed correlation with field data for some of the parameters compared.
Control of pre‐ and post‐emergence damping‐off of potato seedlings caused by Rhizoctonia solani in Peru
Authors: ELANGO FRITZ 
Published: February 2008

SUMMARYFungicide treatment of soil and true potato seed and the use of subsoil as a growth medium significantly reduced pre‐emergence damping‐off caused by Rhizoctonia solani. Attempts were made to determine safe levels of fungicides for soil and seed treatments. For seed, safe levels varied between 0–9% a.i. for pentachloronitrobenzene (PCNB) and 3‐0% a.i. for mancozeb (dithane M‐45).Fungicides only marginally reduced post‐emergence damping‐off of transplants raised from true potato seed but gave significant increase in yield. The prospects of using fungicide treatment of true seed to control damping‐off in seed beds and in direct field sowing are discussed.
An association of carbohydrates with particles of arabis mosaic virus retained within Xiphinema diversicaudatum
Authors: ROBERTSON W. M. , HENRY CAROL E. 
Published: February 2008

SUMMARYSections through the odontophore of Xiphinema diversicaudatum showed two types of staining for carbohydrates using the periodic acid ‐ thiosemicarbazide ‐silver proteinate (PA‐TSC‐SP) reaction. The first consisted of thin, localised, intensely‐stained patches on the lining of the food canal of all the specimens examined. The second type, found only in nematodes exposed to AMV‐infected plants, revealed cloud‐like areas of carbohydrate ‐ containing material associated with the stained patches on the lining of the food canal. By staining alternate sections with uranyl acetate/lead citrate, these carbohydrate clouds were shown to contain virus particles. Although the cloud material could have originated from either the plant or the nematode, sections through a pellet of partially purified virus particles prepared from plants did not stain for carbohydrate. The possible role of carbohydrate in virus retention and transmission is discussed.
Production of monoclonal antibodies for the detection of potato virus Y
Authors: ROSE D. G. , HUBBARD A. L. 
Published: February 2008

SUMMARYMonoclonal antibodies (McAb) were obtained to potato virus Y (PVY) after immunisation of BALB/c mice with purified PVY, tobacco necrotic strain (PVYn). Spleen cells from a mouse showing a high serum titre were used for fusion with X63NS1 myeloma cells. Hybridomas were selected in medium containing HAT. Culture supernatants were screened for antibody production against PVY, ordinary strain (PVY0) and PVYn using indirect ELISA.Clones of interest were further cross‐reacted with 12 isolates each of PVY0 and PVYn and two isolates of potato virus A (PVA) and healthy sap.For further trials, two clones which reacted specifically with PVYn isolates and one which detected all PVY isolates except two of potato virus C (PVC) were selected.
The role of awns in the resistance of cereals to the grain aphid, Sitobion avenae
Authors: ACREMAN T. M. , DIXON A. F. G. 
Published: February 2008

SUMMARYSix genotypes of awned spring wheat were more resistant to Sitobion avenae than de‐awned wheat. Aphids that fed on awns were up to 22% less fecund and were more likely to be dislodged than aphids that fed elsewhere on an ear. These two factors reduced aphid population growth on awned earing plants in the field to a third of that observed on awnless plants. As awns may also benefit yield and are easy to select for it is recommended that awned winter wheats could be bred and used to reduce the incidence of outbreaks of S. avenae.
The effects of storage atmosphere and temperature on the keeping quality of Spartan apples
Authors: STOW J. 
Published: February 2008

SUMMARYThe rate of softening of apples of the variety Spartan was reduced by addition of 6 or 8% CO2 to a storage atmosphere of 2% O2 at 1 ‐5 oC. This effect was observed in three seasons and in samples from five sources. Sensory assessments suggested that addition of carbon dioxide to the storage atmosphere had no adverse effect on eating quality.Storage in 2% O2 at – 1 oC was as effective in maintaining flesh firmness as 8% CO2+ 2%O2 at 1–5 oC.Strategies for further reductions in firmness loss during storage of Spartan apples are discussed.
Bulbil production in Narcissus: the effect of temperature and duration of storage on bulb unit development and subsequent propagation by twin‐scaling
Authors: HANKS GORDON R. , SHAIK G. , JONES S. K. 
Published: February 2008

SUMMARYThe growth of bulb components and carbohydrate content of Narcissus bulbs was followed during storage at 5–30 oC, and the productivity of twin‐scale propagules cut from bulbs after these storage treatments was studied. Growth of daughter bulb unit components was greatest during storage at 9–15 oC, and greatly inhibited at 30 oC. Concentrations of soluble sugars were highest following 30 oC storage, and higher in intermediate bulb scales than in outer or inner scales. Bulbil production on twin‐scales was greatest on propagules cut from the intermediate scales, and in bulbs previously stored at 15 or 30 oC.
Failure of British isolates of beet western yellows virus to infect potato
Authors: BARKER H. 
Published: February 2008

SUMMARYPotato cultivars were tested for susceptibility to two British isolates of beet western yellows virus originally obtained from sugar beet and oil seed rape. Neither isolate was transmitted by Myzus persicae to virus‐free potato plants, either by itself or in association with potato leafroll virus.
Spectral reflectance of healthy and diseased watermelon leaves
Authors: BLAZQUEZ CARLOS H. , EDWARDS GEORGE J. 
Published: February 2008

SUMMARYSignificant differences in reflectances were found between healthy and diseased watermelon leaves in the 500–640 nm visible region and 740–900 nm near infrared regions of the electromagnetic spectrum. Spectrophotometric reflectance measurements were made to determine differences between healthy and diseased watermelon (Citrullus vulgaris) leaves over the 500–2700 nm wave length interval. Plants with Fusarium wilt, downy mildew (Pseudoperonospora), and watermelon mosaic were observed during the growing season. Early symptoms of the diseases had significantly greater reflectance values than the advanced stages of the diseases. A ratio of two wavelength bands, 500–640 nm and 660–900 nm gave an accurate index for determining stages of disease, both early and advanced. There were greater differences in reflectance between all three diseases and healthy leaves in both early and advanced stages in the 900–1400 nm, 1500–1900 nm, and 2000–2400 nm middle infra‐red wavelengths of the electromagnetic spectrum than in the visible 450–740 nm range. All three diseases had significant differences in the 700–900 nm near‐infra‐red range.
The association of Pythium spp. with cavity spot and root dieback of carrots
Authors: WHITE J. G. 
Published: February 2008

SUMMARYThe possibility of an association between cavity spot and root dieback of carrots has been demonstrated, along with control of both disorders by soil sterilisation with methyl bromide or seed and soil treatment with metalaxyl. When carrots were grown in sterilised soil into which five Pythium spp. were introduced individually, cavity spot occurred and the Pythium spp. were re‐isolated from cavities. The relatively slow growing Pythium violae gave the highest percentage of carrots with cavities.In a laboratory test a range of Pythium spp. produced cavities on carrots previously grown in sterilised soil, and with one exception were re‐isolated from those cavities.
The manipulation of white clover ‘host preference’ for strains of Rhizobium trifolii in an upland soil
Authors: RENWICK ANNABEL , JONES D. GARETH 
Published: February 2008

SUMMARYThe nodule occupancy of white clover cv. Milkanova three months after inoculation in an upland soil with a 1:1 mixture of an effective (CP3B) and an ineffective strain (R4) of R. trifolii, differed significantly depending on the lime level. The percentage of nodules occupied by the effective strain decreased from 64% to 29% with increasing lime level whilst the ineffective strain nodules increased from 4% to 24% with mixed nodule infections also increasing from 9% to 22% There was no such difference after 14 months with this cultivar nor with cv. S184 at either harvest. Inoculation with a higher ratio of the less preferred strain (R4) resulted in this strain dominating the nodules and significantly reducing the dry weight of the plants (first harvest) and clover cover of plots (second harvest). Where antibiotic resistant mutants of these strains were used, with one exception, there were no significant differences between the wild‐type strains and their mutant derivatives for any of the parameters measured. In a comparison of the two marker techniques used, fluorescent ELISA was less sensitive than the antibiotic resistance technique for the identification of the occupants of small ineffective nodules. The use of both techniques in large field experiments is discussed. Clover establishment was affected by lime level during the establishment phase but the beneficial effect of lime had disappeared by the second harvest year.
Virus diseases of celery in England
Authors: PEMBERTON A. W. , FROST R. R. 
Published: February 2008

SUMMARYAbnormal celery plants (Apium graveolens) with symptoms typical of virus infection were collected from 28 farms in Cambridgeshire, Lancashire, Lincolnshire, and Norfolk; six different diseases were found. The causal viruses from three of these were isolated and partially characterised. Cucumber mosaic virus was quite common, but usually symptomless; it had no effect on the growth of four celery cultivars in field trials. Celery virus 036 was serologically related to western celery mosaic virus, had a host range apparently confined to Umbelliferae, and was very common in the Fens, causing ringspot symptoms in some cultivars and a loss in yield of up to 24%. This disease was much less severe than that caused by an American isolate of western celery mosaic virus in glasshouse comparisons. Celery virus 065 (an unidentified isometric virus, 28–30 nm in diameter) was less common, had a very wide host range, and caused stunting, necrosis, and chlorotic flecking in all cultivars with a loss in yield of up to 45%. Of the remaining three diseases, celery yellow spot was common; the causal agent was transmitted by mechanical inoculation, but very inefficiently, and although yield losses were not determined accurately, they were thought to be insignificant. While plants with symptoms typical of celery yellow net and celery strap leaf diseases were often found, no viruses could be isolated from them, despite repeated attempts.
A field study of the pattern of local spread of ryegrass mosaic virus in mown grassland
Authors: HEARD A. J. , CHAPMAN P. F. 
Published: February 2008

SUMMARYIn a field experiment at Hurley, small areas of old ryegrass sward, known to be infected with ryegrass mosaic virus (RMV) were partially surrounded by newly‐sown Italian ryegrass. The experiment was harvested by mowing on five occasions. Samples of Italian ryegrass taken when it was 11 months old showed a very marked increase in the levels of RMV close to the areas of old sward. Thus, 84% of the Italian ryegrass plants bordering the old sward to the north contained RMV, compared with 63% of plants only 2.7 m away. The corresponding values to the south were 68% and 39%. The much higher values encountered to the north are presumed to be caused by the movement of the mite vector of RMV (Abacarus hystrix) in relation to the prevailing wind.Two different mowers were used, a rotary mower and a reciprocating knife mower. We could demonstrate no increase in the level of RMV as a result of mowing from the infected sward and on to the new sowing and could demonstrate no difference in the infection levels as a result of using the different mowers.We conclude that in mown swards migration by the mite is responsible for all or nearly all of very local spread of RMV.
The effect of potato trap crops and fallow on decline of Globodera rostochiensis
Authors: LAMONDIA J. A. , BRODIE B. B. 
Published: February 2008

SUMMARYThe effects of 1 to 6 wk growth of resistant and susceptible potato cultivars on Globodera rostochiensis population decline were studied in pot and microplot experiments. In pot experiments, potato plants were hand pulled or killed with glyphosate herbicide at weekly intervals for 4 or 6 wk after shoot emergence. In microplot experiments, potato plants were killed with glyphosate herbicide weekly for 4 wk after shoot emergence. After 4 wk the number of viable eggs had declined more in pots where potato plants were grown (66–87%) than in pots of fallow soil (35%). Although decline in numbers of viable eggs under resistant and susceptible cultivars did not differ significantly, there was a trend towards greater decline under resistant plants. Duration of plant growth was positively correlated with decline in viable eggs when plants were killed with glyphosate but not when they were hand pulled. However, in microplot experiments using glyphosate, decline in viable eggs after 1 wk of potato plant growth (55%) was not different from that after 4 wk (57%). Numbers of viable eggs in fallow soil declined less 5 cm deep (34%) than 15 cm deep (50%). All of the viable eggs contained in cysts on the soil surface died within 5 months, probably due to high temperature.
Field assessment of the effectiveness of a barley yellow dwarf virus resistance gene following its transference from spring to winter barley
Authors: PARRY A. L. , HABGOOD R. M. 
Published: February 2008

SUMMARYResistance to infection by barley yellow dwarf virus (BYDV) has been transferred to the winter‐hardy barley cv. Vixen. The effects of various sowing and inoculation dates on this resistance have been studied at two levels of BYDV infection. At levels most likely to be encountered in the field cv. Vixen suffered only slight yield losses and even under the most extreme conditions consistently yielded more than the susceptible cv. Igri. Comparison of the range of measurements used to determine the effects of BYDV infection showed that assessment of resistance to BYDV in field‐grown winter barleys is most reliably based on yield measurements.
The influence of plant density and position in field trials designed to evaluate the resistance of carrots to carrot fly (Psila rosae) attack
Authors: ELLIS P. R. , FREEMAN G. H. , DOWKER B. D. , HARDMAN J. A. , KINGSWELL GAIL 
Published: February 2008

SUMMARYThe results of field trials designed to evaluate the resistance of carrots to carrot fly (Psila rosae) attack were influenced by plant density and position within trials. Five trials are described, their results analysed and implications for future work discussed. Density effects were of major importance when the range of densities within a trial was greater than about three‐fold. Density and damage were associated, carrot cultivars and families with the most roots having the least damage; plant densities achieved should therefore be as close as possible to the targets set. Positional effects were often very important, so trials should ideally have no more than about 10 plots in a block, possibly by using an incomplete block design. Conventional analyses of variance removing block effects may be sufficient but it is desirable, especially with large blocks, to use some form of nearest neighbour analysis for which the various possible techniques gave similar results.
Incidence of endophytes in seeds from collections of Lolium and Festuca species
Authors: LATCH G. C. M. , POTTER L. R. , TYLER B. F. 
Published: February 2008

SUMMARYSeeds from 53 of 64 collections of Lolium perenne from its centre of origin or from old pastures in Europe were found to be infected with endophyte whereas only four of 16 commercial cultivars had infected seed. Almost two thirds of seed samples of L. multiflorum, Festuca arundinacea and F. pratensis collected from plants growing in the wild in Italy contained endophyte but none of the eight commercial cultivars of L. multiflorum and only two of five cultivars of Festuca spp. produced by the Welsh Plant Breeding Station were infected. At least one seed sample from each of six species and varieties of annual ryegrasses contained endophyte mycelium. Endophytes in annual ryegrasses could not be cultured axenically and are probably a different species to the Acremonium lolii present in L. perenne. A correction to the spelling of the specific epithet of A. lolii is explained.