bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some effects of temperature during seed development on carrot (Daucus carota) seed growth and quality
Authors: GRAY D. , STECKEL JOYCE R. A. , DEARMAN JANE , BROCKLEHURST P. A. 
Published: February 2008

SUMMARYThe growth and development of carrot seeds cv. Chantenay Red‐cored Royal Chantenay at day/night temperatures of 20/10°C, 25/15°C and 30/20°C and subsequent seed performance were examined in 1984 and 1985.An increase in temperature from 20/10°C to 30/20°C reduced mean weight per seed by 20% in 1984 and by 13% in 1985. There were no effects of temperature on endosperm + embryo weight, or on endosperm cell number but the weight of pericarp decreased with an increase in temperature. Seeds grown at the highest temperature had the largest embryos and the highest nitrogen, DNA and rRNA content; they germinated and emerged earlier, and gave higher percentage seedling emergence than those grown at the lowest temperature. There were no effects of temperature during seed growth on the rate of imbibition of water by seeds during the germination process.
Substituted benzoic and picolinic acids as foliar sprays against potato common scab
Authors: McINTOSH A. H. , BATEMAN G. L. , CHAMBERLAIN K. 
Published: February 2008

SUMMARYGlasshouse tests on potato cv. Arran Banner measured the effects of single early foliar sprays of 18 substituted benzoic and two dichloropicolinic acids on the severity of common scab, caused by soil‐borne Streptomyces scabies.The monosubstituted benzoic acids tested (25 mM) did not affect scab. However, anti‐scab action was shown by some 2,5‐disubstituted acids. Decreases in scab severity were about 35% from 1·6 mM 5‐bromo‐2‐chloro‐ and 2,5‐dimethylbenzoic acids, and over 50% from 1·6 mM 2,5‐dichloro‐, 2,5‐dibromo‐ and 5‐chloro‐2‐nitrobenzoic acids and from 0·05 mM 3,6‐dichloropicolinic acid (clopyralid), which is structurally similar to 2,5‐dichlorobenzoic acid.None of the spray treatments affected yield or shape of tubers. No visible effects on foliage were caused by two of the benzoic acids active against scab (5‐chloro‐2‐nitro‐ and 2,5‐dimethyl‐), but the other active acids caused some distortion.In tests of the six dichlorobenzoic acids against S. scabies in culture, the 2,5‐isomer (which was the most effective against the disease in plants) was one of the least toxic. With other 2,5‐disubstituted benzoic acids, it probably decreased scab indirectly by altering the response of the host to infection.
Studies on the transmission of velvet tobacco mottle virus by the mirid, Cyrtopeltis nicotianae
Authors: GIBB KAREN S. , RANDLES J. W. 
Published: February 2008

SUMMARYThe minimum acquisition period of velvet tobacco mottle virus (VTMoV) by its mirid vector Cyrtopeltis nicotianae was about 1 min, with an increase in the rate of transmission (i.e. proportion of test plants infected) for acquisition periods up to 1000 min. Pre‐acquisition starvation periods up to 18 h did not affect the rate of transmission. After an acquisition access period of 2 days, the minimum inoculation period was between 1 and 2 h and the rate of transmission increased with increasing inoculation time; when the acquisition access period was 1 h, or if vectors were fasted for 16 h after the 2 day acquisition, the rate of transmission was significantly lower. When mirids were transferred sequentially each day to a healthy plant after a 24 h acquisition feed, they transmitted intermittently for up to 10 days. Up to 50% of mirids transmitted after a moult and this was not due to the mirids probing the shed cuticles or exudates of infective insects. Mirids transmitted after a moult, following acquisition periods of 10, 100 or 1000 min. C. nicotianae transmitted solanum nodiflorum mottle virus (SNMV), sowbane mosaic virus (SoMV) and southern bean mosaic virus (SBMV), but not subterranean clover mottle virus (SCMoV), lucerne transient streak virus (LTSV), tobacco ringspot virus (TRSV), galinsoga mosaic virus (GMV), nor nicotiana velutina mosaic virus (NVMV). Tomato bushy stunt virus (TBSV) was transmitted to 1/58 test plants.
Electronic recording of plant penetration by the cereal aphids Rhopalosiphum padi and Metopolophium dirhodum on resistant and susceptible wheat seedlings
Authors: SPILLER N. J. 
Published: February 2008

SUMMARYPlant penetration by the aphids Rhopalosiphum padi and Metopolophium dirhodum was monitored using an electronic recording method. Recordings over 3 h showed that phloem ingestion was reduced on resistant wheat, when compared with a more susceptible species, but this trend was reversed when results from longer (12 h) experiments were used. Plant penetration by M. dirhodum was reduced by attachment to the electronic system, but the behaviour of R. padi was relatively unaffected. The results are discussed in relation to prospects for using electronic methods as a screening procedure.
Observations on the pathogenicity of Pasteuria penetrans, a parasite of root‐knot nematodes
Authors: DAVIES K. G. , KERRY B. R. , FLYNN C. A. 
Published: February 2008

SUMMARYA simple test was used to determine whether or not Pasteuria penetrans spores would attach to 17 species of nematodes. All susceptible individuals had spores attached to their cuticles after 24 h of gentle agitation in suspensions containing 105spores/ml. Spores of P. penetrans from six populations of Meloidogyne only adhered to species of Meloidogyne and they adhered in greatest numbers to the species from which they had been originally isolated. Sonication of spores from infected females increased attachment but the effect was dependent on pH and whether the test was conducted in tap or distilled water. Invasion of tomato roots was reduced by up to 86% when, rather than using healthy juveniles, second‐stage juveniles bearing 15 or more spores were added to soil at high densities (1000 or 3000/plant); at low densities (500/plant) invasion was not significantly affected. The rate of development of M. incognita juveniles infected with P. penetrans was slower than that of healthy juveniles. The numbers of second‐generation of M. incognita were reduced by 82–93% when juveniles encumbered with 1–15 spores were added to soil instead of those bearing no spores. Pasteuria penetrans populations differed in their aggressiveness and when juveniles encumbered with the same number of spores from two populations were added to soil there were differences in the numbers of females that became infected. The implications of these results for the development of P. penetrans as a biological control agent are discussed.
Seasonal variation of morphological characters and growth in contrasting white clover populations
Authors: EAGLES C. F. , OTHMAN O. B. 
Published: February 2008

SUMMARYThe seasonal growth potential of contrasting white clover populations differing in leaf size and geographical origin was studied during the year in a cool glasshouse in the absence of freeze damage.A Mediterranean population showed superior growth to all other populations during the cooler months of late autumn, winter and spring when it also had longer leaflets, petioles and internodes. In contrast, large leaf types of north European origin grew faster and had longer leaflets, petioles and internodes than the Mediterranean type during summer. A hybrid between these contrasting types showed an intermediate response with more uniform growth and expression of these morphological characters throughout the year.The exploitation of this out‐of‐season growth potential by hybridisation of Mediterranean and north European genotypes followed by selection is discussed in the context of recent introductions of ecotypes from the Swiss Alps in which desirable combinations of good spring growth and winter hardiness have been identified.
Transmission of pangola stunt virus by Sogatella kolophon
Authors: GREBER R. S. , GOWANLOCK D. H. , HICKS S. , TEAKLE D. S. 
Published: February 2008

SUMMARYA fijivirus causing minor enations, stunting, leaf notching, seed head deformity and excess tillering of Digitaria spp. was transmitted from naturally infected Digitaria ciliaris to D. ciliaris, D. decumbens and Urochloa panicoides by the planthopper Sogatella kolophon; 40–70% of insects transmitted after an incubation period of 15–21 days, and continued to transmit for up to 30 more days until death. Symptoms developed in test plants 30–50 days after inoculation. Sogatella longifurcifera failed to transmit the virus under similar conditions. Virus particles were present in roots, stems and leaves of infected plants, and particles were found in regular arrays and random aggregates in fat body cells of transmitting insects. Viroplasm and tubular structures were associated with these particles. Extracts from infective insects contained 10‐segment dsRNA when analysed by polyacrylamide gel electrophoresis. Virus survives over winter in planthoppers and D. ciliaris seedlings in frost‐free areas of coastal Queensland, but infected plants have debilitated root systems and compete poorly with healthy plants.
The assessment of the tolerance of partially resistant potato clones to damage by the potato cyst nematode Globodera pallida at different sites and in different years
Authors: DALE M. F. B. , PHILLIPS M. S. , AYRES R. M. , HANCOCK M. , HOLLIDAY M. , MACKAY G. R. , TONES S. J. 
Published: February 2008

SUMMARYA range of potato cultivars and clones was grown at three sites infested with Globodera pallida in each of four years (1983 – 1986). Comparison of yields from nematicide treated plots with those of untreated plots provided estimates of yield losses due to G. pallida. The proportional yield losses were calculated for each genotype at each site as a measure of nematode tolerance. There were significant differences between genotypes with regard to tolerance of damage by G. pallida. There were also significant interactions between the different genotypes and the sites and years, but the interactions between years and genotypes represented only a small proportion of the observed variation. The interactions between sites and years indicate that not all of the genotypes behaved consistently between sites and years. The extent of yield losses caused by the nematodes varied significantly between sites. The implications of these results are discussed in relation to potato breeding programmes and assessing resistance and tolerance to G. pallida.
Genotypic responses of scab‐resistant apple cultivars/selections to two strains of Erwinia amylovora and the inheritance of resistance to fire blight
Authors: KORBAN S. S. , RIES S. M. , KLOPMEYER M. J. , MORRISEY J. F. , HATTERMANN D. R. 
Published: February 2008

SUMMARYApple cultivars and selections were tested for resistance to two strains of Erwinia amylovora following shoot tip inoculation in the greenhouse. Cv. Liberty was resistant to strain Ea 273, and Priscilla, Delicious and Coop 17 were highly resistant to strain Apple # 1. A significant genotype x strain interaction was obtained suggesting a differential host × pathogen interaction.Segregation of seedlings derived from 16 controlled crosses after fire blight inoculation indicated that resistance to fire blight is quantitatively controlled with evidence for presence of dominant additive gene effects.
Biocontrol of Rhizoctonia crown and root rot of sugar beet by binucleate Rhizoctonia spp. and Laetisaria arvalis
Authors: HERR LEONARD J. 
Published: February 2008

SUMMARYTwo isolates of Laetisaria arvalis and 10 of binucleate Rhizoctonia spp. (BNR) from the Ohio sugar beet production area, were tested in the greenhouse and field for biocontrol of Rhizoctonia crown and root rot of sugar beet, caused by Rhizoctonia solani anastomosis group 2, type 2. L. arvalis was ineffective in standard greenhouse tests, and the single isolate used in the field was generally ineffective. Seven of 10 BNR isolates effectively controlled crown and root rot in greenhouse tests. Delayed application of biocontrol agents to plants 5 – 10 wk old was generally more effective than applications made at planting. A BNR isolate significantly reduced % plant loss and disease ratings and increased yield in a 1985 field test as compared with the control infested with R. solani alone. Two BNR isolates were effective in a 1986 field test and increased yields c. 22% in comparison to a L. arvalis treatment, which did not differ from the R. solani‐infested control. The Ohio binucleate Rhizoctonia isolates appear to have considerable potential as applied biocontrol agents and may play a role in the natural ecology of R. solani in the sugar beet production area of Ohio.
The inhibition of potato sprout growth by light.
Authors: MCGEE E. , BOOTH R. H. , JARVIS M. C. , DUNCAN H. J. 
Published: February 2008

SUMMARYThe effect of light intensity on sprout growth in seed potato tubers (Solanum tuberosum) was examined using diffuse daylight in Peru and diffuse artificial light at Glasgow. Mean temperatures below 20 °C produced strong sprout growth that was inhibited by both daylight and artificial light, at visible irradiances above 0.01 Wm‐2. The percentage inhibition of sprout growth increased linearly with the logarithm of the irradiance, 50% inhibition being at 0.04 ‐ 0.1 Wm‐2 provided that the temperature was suitable for substantial sprout growth in the absence of light.Cultivar and temperature had very little effect on the 50% inhibition point. At high irradiances growth inhibition was up to 95%, but the sprout length was never reduced to zero; short, robust green sprouts remained. Sprout numbers were increased by daylight, but not by artificial light. Diffuse daylight also reduced the total weight loss from seed tubers during a storage season of 180 days. At mean temperatures above 20 °C., sprout growth in the absence of light was much reduced and the effect of light on sprout elongation was less obvious.
The inhibition of potato sprout growth by light.
Authors: MCGEE E. , BOOTH R. H. , JARVIS M. C. , DUNCAN H. J. 
Published: February 2008

SUMMARYIn an experiment with eight potato cultivars at Huancayo, Peru, storage of seed tubers in a prototype diffuse‐daylight store resulted in a mean 17% increase in the yield of the subsequent crop, and in more rapid emergence of six of the cultivars after planting, as compared with seed stored in darkness. The dark‐stored seed had very long sprouts that had to be removed at planting.In two experiments at Glasgow, Scotland, seed tubers of four cultivars were stored at a range of temperatures in darkness and artificial light. At the time of planting, some of the light‐stored tubers were desprouted as well as the dark‐stored ones, so that the effect of desprouting could be distinguished from any direct effect of storage in darkness. Desprouting consistently delayed emergence and senescence of the crop and in most cases reduced its yield. In 1983 the yield reduction was greatest in the first early cV. Home Guard after storage at high temperature (22 °C), when it was associated with low stem numbers and incomplete emergence. In 1984 after light storage at still higher temperature (22/33 °C) and desprouting, this cV. behaved similarly, but the corresponding dark‐stored treatment yielded heavily after greatly delayed haulm senescence. CV. Desiree and, in 1984, cV. King Edward retained some apical dominance after storage at the lower temperatures and in some cases responded to desprouting with a small yield increase.In general desprouting after high‐temperature storage reduced yields more than could readily be explained on the basis of the physiological age being reset to zero at planting.
Chemical retting of flax using chelating compounds
Authors: SHARMA H. S. SHEKHAR. 
Published: February 2008

SUMMARYA wide range of concentrations of ethylenediaminetetra acetic acid (EDTA) was tested as a retting agent at a range of temperatures, pHs and stem: liquor ratios. Treatment of stems at 2 and 3 g/litre at 40 °C in a liquor ratio of 1:10 at pH 11 produced the finest and strongest fibre. Dried‐green stem retted slightly better than the glyphosate‐desiccated stem and after multiple retting with EDTA, Trilon TB and diethyltriaminepenta acetic acid (DTPA), the dried‐green stem produced the finest fibre. Trilon TB and DTPA retted better than EDTA and produced a high yield of fibres. The fluidity of fibres scutched from the dried‐green stem was lower than the fluidity of the fibres from glyphosate‐desiccated stem.
Studies on the biology and control of cavity spot of carrots
Authors: WHITE J. G. 
Published: February 2008

SUMMARYUsing a selective medium of corn meal agar with pimaricin and rifamycin, isolations from asymptomatic periderm of carrots grown on experimental plots or in commercial crops most frequently yielded the fast‐growing species Pythium intermedium, P. sylvaticum or P. ultimum. In contrast isolations from cavity spot lesions mostly produced the slow‐growing species P. violae and P. sulcatum. Following treatment of crops with metalaxyl + mancozeb, few isolations from asymptomatic periderm produced Pythium spp. and generally there was a reduction in the number of cavities. Treatment had little or no effect on size distribution of cavities. Cavity spot incidence was significantly less at higher pH values, fields of pH 8·0 and above producing carrots with little or no disease.
Variation in the sensitivity to metalaxyl of Pythium spp. isolated from carrot and other sources
Authors: WHITE J. G. , STANGHELLINI M. E. , AYOUBI L. M. 
Published: February 2008

SUMMARYOver a 3‐yr period 261 isolates of 17 species of Pythium were tested for sensitivity to metalaxyl at concentrations of 5, 50 or 100 μ/ml. A wide range of responses was observed, from isolates where growth ceased at 5 μg/ml to those where growth at 100 μg/ml was similar to that of the untreated controls. In further tests isolates of 11 different species had ED50's < 1 μg/ml. A lower sensitivity was detected in isolates of six Pythium spp. where values in the range 1–10 μg/ml were obtained.This lower sensitivity was not related to previous known use of metalaxyl. Three isolates of Pythium dissotocum from sites where the fungicide had been used repeatedly had ED50's > 100 μg/ml and were considered resistant. The resistance was stable over a 2‐yr period and isolates were cross‐resistant to furalaxyl, benalaxyl, ofurace, cyprofuram and oxadixyl. Increasing concentrations of metalaxyl reduced or prevented the production of zoospores by four species of Pythium, although when zoospores were produced, this was followed by the normal processes of encystment and germination. Culturing P. dissotocum on different sub‐lethal concentrations of metalaxyl for 18 wk did not induce a high level of resistance to the fungicide.
The ploidy of plants obtained from anther culture of cauliflowers (Brassica oleracea var. botrytis)
Authors: OCKENDON D. J. 
Published: February 2008

SUMMARYAnther culture of four cultivars of autumn cauliflower gave embryo yields of 100 embryos (per 100 anthers cultured) for one cultivar, eight embryos for a second cultivar, and almost zero for the two other cultivars. From 986 embryos which were grown on, 418 plants were regenerated. The ploidy of the regenerants was assessed by measuring guard cell lengths, pollen size, and by chromosome counts at meiosis. Only 1% of the regenerants were haploid, 41% diploid, 5% triploid and 53% tetraploid. One octoploid plant was also found. The results are discussed in relation to equivalent results for Brussels sprouts, and the use of anther culture in the breediing of cauliflowers.
Light‐induced postharvest regreening of pummelo fruit*
Authors: SAKS YOLANTA , WAKS YEHOSHUA , WEISS BATIA , FRANCK ANDRE , CHALUTZ EDO 
Published: February 2008

SUMMARYRegreening was observed and measured in harvested pummelo fruit stored in the light. At temperatures of 22 ‐ 28°C, regular daylight was sufficient for regreening to occur. The addition of continuous fluorescent light intensified the process. Pre‐stored fruit held in darkness at 11°C and non‐stored fruit responded to both light conditions in a similar manner. Electron microscopy has shown that globular chromoplasts revert to chloroplasts during regreening. The similarities between regreening processes in preharvest and postharvest fruits are discussed.
Influence of post‐flowering temperature on seed development, and subsequent performance of crisp lettuce
Authors: GRAY D. , WURR D. C. E. , WARD J. A. , FELLOWS JANE R. 
Published: February 2008

SUMMARYCrisp lettuce plants cv. Saladin were grown from the time they started flowering, at 20/10°C (16 h day, 8 h night), 25/15°C and 30/20°C in glasshouses on two occasions in 1985.Yields of seed increased from, on average, 15 g to 27 g and then fell to 20 g per plant with progressive increases in temperature. The number of mature florets per plant increased with temperature but the number of seeds per mature floret was lower at 20/10°C and 30/20°C than at 25/15°C. An increase in temperature reduced mean seed weight by up to 45%, seed volume by 15%, cell numerical volume density (Nv) by 27% and the number of cells per seed by 39%. Percentage seed germination reached a maximum early in seed development at the stage when the pappus appeared through the involucral bracts. Differences in percentage germination and vigour of seeds (slope test) from different temperatures were accounted for largely by the effects on mean seed weight. However, when germinated at 30°C seeds produced at 30/20°C germinated more readily than those produced at 25/15°C or 20/10°C. Seed vigour gradually increased with an increase in the length of storage after harvest, reaching a maximum after 260 days. In general, seeds produced at 25/15°C exhibited a greater variation in numbers of seeds per floret, Nv, seed weight, times of seedling emergence, seedling and mature head weight than seeds produced at lower or higher temperatures.
A study of the optimum drying conditions for cabbage seed following selection on the basis of a newly‐emerged radicle
Authors: FINCH‐SAVAGE W. E. , McKEE J. M. T. 
Published: February 2008

SUMMARYA series of experiments were carried out to study the effects of different drying regimes on the survival of newly‐germinated (radicle emerged 0·5‐1·5 mm through the seed coat) cabbage seeds and to establish a treatment for reducing the moisture content of these germinated seeds. A preliminary surface‐drying step proved necessary to avoid seed agglutination during the main drying stage. Of the drying regimes compared both viability and vigour were most effectively maintained in air, conditioned to between 20 and 30°C and with 80% r.h., flowing through the seeds at 0·25 m s‐1. Under these conditions, the viability and vigour of newly‐germinated seed was maintained during drying to an equilibrium moisture content of c. 14%. At this moisture content further radicle growth was prevented and seeds remained free‐flowing and separate for sowing or for further treatment.
Control of potato gangrene by thiabendazole in relation to time of harvest after haulm destruction and site of production
Authors: CARNEGIE S. F. , HIDE G. A. , RUTHVEN A. D. , LINDSAY D. A. , ADAMS M. J. 
Published: February 2008

SUMMARYThe efficiency of thiabendazole in controlling gangrene on potato tubers harvested on different dates was assessed over two years in Scotland (East Craigs) and England (Rothamsted). At East Craigs the incidence of gangrene on wounded and cold‐stored tubers was greater than on those tubers kept at ambient store temperatures and graded in January, but the assessments were correlated. The incidence of gangrene increased with delay in harvest after haulm destruction although the pattern differed with year and site. Dipping tubers in thiabendazole or sodium hypochlorite almost eliminated gangrene on all harvest dates at Rothamsted but at East Craigs the incidence of gangrene on dipped tubers was much greater and tended to increase the longer the interval between haulm destruction and harvest. Furthermore, dipping tubers in thiabendazole was much more effective than spraying even though the fungicide residues were twice as large with the latter treatment. All 43 isolates of Phoma foveata collected in Scotland were sensitive to thiabendazole in agar plate tests. The results are discussed in relation to disease development at each of the sites.