bluuebunny/crossref_metadata_2025_split huggingface dataset:
Components of partial resistance to Septoria nodorum in winter wheat
Authors: LANCASHIRE PETER D. , JONES D. GARETH. 
Published: February 2008

SUMMARYComponents of partial resistance to Septoria nodorum were investigated in 10 cultivars of winter wheat having similar field resistances. The components measured were infection frequency, latent period, size, shape and rate of growth of lesions, spore production and its rate of increase. Latent period was found to be lognormally distributed. Some of the components of resistance were found to be significantly different between cultivars. Cluster analysis also showed that cultivars could be distinguished on the basis of their components of resistance. Principal components analysis indicated that resistance could be broken down into four underlying factors, three of which could be readily interpreted. The measurements of the components of resistance were combined in a model, the r‐index, based on Van der Plank's r. The amount of variation between cultivars cast some doubt on the predictive value of the index but all the cultivar values were well within the range bounded by two ‘synthetic’ cultivars made up of combinations of either the most resistant or the most susceptible components. It is considered that the r‐index has potential in screening for field resistance. The possibility of incorporating the most resistant‐type components into one cultivar is discussed. The use of cultivar mixtures containing cultivars having similar field resistances is also discussed in the light of the variability found in this study.
Race specific resistance to lettuce downy mildew (Bremia lactucae) in the lettuce cultivar Bourguignonne Grosse Blonde d'Hiver
Authors: NORWOOD JUDITH M. , CRUTE I. R. 
Published: February 2008

SUMMARYA stock of lettuce cv. Bourguignonne Grosse Blonde d'Hiver used in previous studies was shown to carry the race specific resistance factor R1 and not R9 as originally thought. Investigations into a commercial stock of cv. Bourguignonne which exhibited a heterogeneous reaction to some B. lactucae isolates showed that it was a mixture of two lines. Each line carried one of two R‐factors (referred to as R9A and R9B) in a homozygous condition, although their identification was made difficult by the presence of R5/8. No plants were found which carried both R9A and R9B.
The effect of insecticides and a plant barrier row on aphid populations and the spread of bean yellow mosaic potyvirus and subterranean clover red leaf luteovirus in Vicia faba in South Australia
Authors: JAYASENA K. W. , RANDLES J. W. 
Published: February 2008

SUMMARYThe effect of the insecticides malathion, demeton‐S‐methyl and disulfoton, and a barley barrier row on the rate and pattern of spread of bean yellow mosaic potyvirus (BYMV) and subterranean clover red leaf luteovirus (SCRLV) in Vicia faba was investigated in field plots with artificially introduced sources of viruses and vectors.The systemic insecticide treatments reduced aphid populations in the plots and this was associated with reduced spread of SCRLV, but not of BYMV. The barley barrier did not affect aphid populations in plots; however, it reduced the spread of BYMV to rows 1 · 1 m from the source but had only a minor effect on the spread of SCRLV.Apterae rather than alates of Aulacorthum solani were implicated in the spread of SCRLV. Spread of BYMV was attributed mainly to alate migrants of Myzus persicae and Macrosiphum euphorbiae, but other aphid species and morphs which occurred in high populations at the times of most rapid virus spread may also have had an active role as vectors of BYMV.
Effects of delaying fungicide treatment of wounded potatoes on the incidence of Fusarium dry rot in store
Authors: HIDE G. A. , CAYLEY G. R. 
Published: February 2008

SUMMARYPotato tubers artificially inoculated with Fusarium solani var. coeruleum or F. sulphureum 3 months after harvest were uniformly wounded and held at 5, 10 or 15°C for up to 21 days before immersion in fungicide suspensions. Holding tubers for 14 days at 15°C (curing conditions) or at 5°C did not alter the incidence of dry rot subsequently developing on tubers stored at 10°C, and holding tubers for up to 21 days at 15°C slightly increased disease caused by both pathogens. Thiabendazole, imazalil and prochloraz applied to tubers immediately after wounding almost completely prevented dry rot. Treatment after 3 days was less effective and the amount of disease increased with further delay; fungicides were more effective on tubers held at 5°C than at 10 or 15°C before treatment and storage, and efficacy of the fungicide was decreased by increasing the amount of inoculum on tubers.Wounds became less susceptible to infection by F. solani var. coeruleum and F. sulphureum when tubers were held at 15°C before inoculation, and the incidence of rots was decreased by 70–80% by delaying inoculation for 7 days. Treating tubers with dichlorophen immediately after wounding slightly increased the disease. The effects of fungicide treatment, curing conditions and wound healing are discussed.
Studies on beet western yellows virus in oilseed rape (Brassica napus ssp. oleifera) and sugar beet (Beta vulgaris)
Authors: SMITH HELEN G. , HINCKES JENNIFER A. 
Published: February 2008

SUMMARYOilseed rape (Brassica napus L. ssp. oleifera) was studied as a potential overwintering host for the sugar‐beet yellowing viruses, beet yellows virus (BYV) and beet mild yellowing virus (BMYV), and their principal vector, Myzus persicae. In spring 1982, plants infected with a virus which reacted positively in enzyme‐linked immunosorbent assay (ELISA) with BMYV antibody globulin were found in oilseed‐rape crops; none of the plants contained virus which reacted with BYV antibody globulin. This virus was subsequently identified as beet western yellows virus (BWYV). No leaf symptoms could be consistently associated with infection of oilseed rape, but the virus was reliably detected by sampling any leaf on an infected oilseed‐rape plant. Some isolates from oilseed rape did infect sugar beet in glasshouse tests, but the proportions of inoculated plants which became infected were low. Apparently there is therefore little danger of much direct transmission of BWYV by M. persicae from oilseed rape to sugar beet in spring.BWYV was introduced to and spread within oilseed‐rape crops in autumn by M. persicae, and autumn‐sown oilseed rape proved to be a potentially important overwintering host for M. persicae. In a survey of 80 autumn‐sown crops of oilseed rape in East Anglia, northern England and Scotland in spring 1983, 78 were shown to be extensively infected with BWYV.Experimental plots of oilseed rape with 100% BWYV‐infection yielded approximately 13.4% less oil than plots with 18% virus infection, the result of a decrease in both seed yield and oil content.
Effects of dalapon and TCA on the growth and yield of oilseed rape (Brassica napus)
Authors: LUTMAN P. J. W. 
Published: February 2008

SUMMARYThe tolerance of oilseed rape (Brassica napus cv. Jet Neuf) to the herbicides dalapon and TCA was studied in two series of 10 experiments over four years. TCA (7.6–30.4 kg a.i./ha) was applied pre‐emergence and dalapon (2.9–11.6 kg a.i./ha) was sprayed post‐emergence between September and November at two growth stages (2–5, 4–7 leaves). Dalapon at all doses caused the leaves to appear yellow‐green in colour and at the higher rates (5.8–11.6 kg a.i./ha), especially when applied at the later of the two growth stages, scorched the leaf margins and stunted the plants. TCA also caused the leaves to appear yellow‐green and was noted to affect the retention of water by the leaf surfaces. In general the visible effects of treatment with dalapon were more severe than those of TCA.The effects of these two herbicides on rape seed yields were variable, with some trials showing statistically significant reductions and others none. However by combining the results of trials with similar treatments some underlying trends were identified. In the overall analyses dalapon at 11.6 kg a.i./ha, applied at both growth stages and at 5.8 kg a.i./ha, applied at the later one, reduced yields significantly. TCA at 15.2, 22.8 and 30.4 kg a.i./ha also caused significant yield reductions in the combined analyses. Further statistical analysis questioned the safety of the lower rates of both herbicides, which were similar to those recommended by the manufacturers. The severity of the foliar damage caused by dalapon was well correlated with the risk of significant yield reductions but not with the actual percentage loss of yield. No such correlations were possible with TCA as the visual symptoms were similar on all sites and were unaffected by dose.Recent changes in agricultural practices and in crop cultivar do not appear to have altered the sensitivity of rape to dalapon and TCA appreciably.
Parsnip (Pastinaca sativa) seed production: effects of seed crop plant density, seed position on the mother plant, harvest date and method, and seed grading on embryo and seed size and seedling performance
Authors: GRAY D. , STECKEL JOYCE R. A. 
Published: February 2008

SUMMARYParsnip seeds from four years of seed production (1980–83) were used to examine the effects of position of the seed on the parent plant and several cultural factors on seed and embryo growth and seedling performance. Maximum seed dry weight was reached c. 50 days after flowering (DAF) but embryos continued to grow for a further 7–15 days. The coefficient of variation (C.V.) of seed weight fell from c. 35–40% at 40 DAF, to about 20–25% at maturity. The corresponding figures for C.V. of embryo length were 25–35% at the early harvest and 12–15% at maturity. The effects of seed position, plant density, harvest method, seed grading after harvest on seedling emergence and weight characters were small. Harvesting seeds c. 60 DAF gave, on average, 3.3 days earlier emergence, c. 3.6 days lower ‘spread’ of emergence time and c. 9% higher seedling emergence than harvesting 2 wk earlier. Late harvesting of the seed crop reduced the C.V. of seedling weight from 53 to 46%, on average, but there were variations in response from year to year. Seedling emergence and seedling weight characters were more closely related to embryo length than to seed weight characters.
Reduction of cabbage root fly (Delia radicum) damage by protective discs
Authors: SKINNER G. , FINCH S. 
Published: February 2008

SUMMARYFoam‐rubber, carpet‐underlay discs placed in position around the base of the stem directly after transplanting were as effective as certain recommended insecticides in protecting brassica plants from damage by cabbage root fly (Delia radicum). The three factors that contributed to the overall effectiveness of the discs were that only half as many eggs were laid around plants protected with discs as around unprotected plants, that predatory ground beetles preferred to aggregate in the humid microhabitat beneath the discs and consequently ate proportionally more fly eggs/larvae and that the discs acted as a mulch, conserving water around the roots of the plants, and thereby permitting them to tolerate greater amounts of damage.Application of the repellent benzyl benzoate to the discs improved effectiveness but 12 other insect repellents and two sticky compounds gave no improvement and most were phytotoxic. Root drenches of the insecticide chlorfenvinphos were repellent, reducing oviposition by approximately 25%. The costs of protecting brassica transplants with either discs or insecticide were similar and discs thus appear to be a reasonable method of cabbage root fly control for small‐scale use.
Factors affecting the development of cane blight (Leptosphaeria coniothyrium) on red raspberries in Washington, Scotland and Germany
Authors: WILLIAMSON B. , BRISTOW P. R. , SEEMÜLLER E. 
Published: February 2008

SUMMARYThe effects of cultivar, virulence of isolates of Leptosphaeria coniothyrium, cane maturation and wound healing were examined in a series of inoculation experiments carried out over a 3–yr period in three countries in an attempt to explain why cane blight has caused serious yield losses in machine‐harvested red raspberries in Europe, but not in the Pacific Northwest of America. Three isolates of L. coniothyrium from Puyallup (USA), Dundee (UK) and Dossenheim (FRG) were pathogenic on the three test cultivars Willamette, Malling Jewel and Glen Isla in all the experiments. Isolates and cultivars differed for aggressiveness and susceptibility respectively but their ranking was dependent on the test conditions and the differences were small and unlikely to explain the differences in incidence and severity of cane blight in raspberry fields in Scotland and the Pacific Northwest. Conditions at Dossenheim were most favorable for lesion development. At all sites, canes inoculated in late summer produced shorter lesions than those inoculated earlier. A delay between wounding and inoculation produced shorter lesions than simultaneous wounding and inoculation.
Purification and properties of ginger chlorotic fleck virus
Authors: THOMAS J. E. 
Published: February 2008

SUMMARYA previously undescribed isometric virus, named ginger chlorotic fleck virus (GCFV), was detected in ginger (Zingiber officinale) imported into Australia from a number of countries. The geographical distribution of the virus is uncertain, but is thought to include India, Malaysia and Mauritius. The virus apparently does not occur in Australian commercial ginger plantings.The virus has isometric particles c. 30 nm in diameter, with a sedimentation coefficient of 111 S, and was readily purified from infected ginger with yields of 50–90 mg/kg leaf tissue. Purified preparations contained a major species of single‐stranded RNA of mol. wt 1.50 × 106 and a major coat protein species of mol. wt 29.0 × 103. At pH 7, the particles formed a single zone in both caesium chloride and caesium sulphate gradients, with buoyant densities of 1.355 g cm‐3 (fixed virus) and 1. 297 g cm‐3 (unfixed virus), respectively. The virus particles migrated as two electrophoretic components and were labile when treated with 10 mM EDTA, 1 M NaCI, 10 mM tris pH 8.25 or when negatively stained with potassium phosphotungstate. GCFV was mechanically transmitted only to ginger, and was not transmitted by the aphids Myzus persicae. Pentalonia nigronervosa, Rhopalosiphum maidis or R. padi. Possible affinities of GCFV with the sobemo‐virus group are discussed.The present cryptogram of GCFV is R/l: 1.5/20: S/S: S/*.
Identification of soybean mosaic, southern bean mosaic and tobacco ringspot viruses from soybean in the People's Republic of China
Authors: XU ZHIGANG , POLSTON JANE E. , GOODMAN ROBERT M. 
Published: February 2008

SUMMARYSamples of soybean plants with virus‐like symptoms were collected from several locations in the People's Republic of China in 1981. These samples were used to prepare inocula for mechanical inoculation to soybean. Twenty‐one virus cultures were obtained, the identities of which were determined by serology, symptomatology and host range. Sixteen cultures contained only soybean mosaic virus, four of which were more pathogenic than any previously studied; one culture contained only tobacco ringspot virus, another only southern bean mosaic virus, and three other cultures mixed infections of soybean mosaic and southern bean mosaic viruses. This is the first report of the occurrence of tobacco ringspot virus and southern bean mosaic virus in soybean in the People's Republic of China.
The effects of applications of gibberellins to the parent plant, harvest date and harvest method on seed yield and mean seed weight of crisp lettuce
Authors: GRAY D. , STECKEL JOYCE R. A. , WURR D. C. E. , FELLOWS JANE R. 
Published: February 2008

SUMMARYThe effects on bolting and flowering of treating crisphead lettuce plants cv. Pennlake with gibberellins 4 and 7 (GA4+7) at the rosette stage were compared with cutting open the mature heads in three experiments (1981–83). In addition, to the effects of GA4+7 treatment, those of two methods of harvesting (‘shake’ and ‘windrow’) and time of harvest on seed production were examined.Compared with plants induced to produce flowering shoots by cutting the mature heads, GA4+7‐‐treatment increased the proportion of plants surviving to produce flowers. It gave more synchronous flowering and it increased seed yields by between 11 and 278% for the ‘shake’ method and by between 33 and 125% for the ‘windrow’ method. There was no consistent effect of method of harvest on seed yield. For windrow harvests, maximum yields were obtained from plants cut between 30 and 45 days after the appearance of the first flowers. Mean seed weight varied between 1. 25 and 1. 62 mg depending on the year of production and harvest date. In 1982 and 1983, the differences in seed weight within any one year were positively associated with differences in mean temperature during the period of seed growth but temperature could not account for the differences in mean seed weight between years.
The effects of seed production techniques on seed characteristics, seedling growth and crop performance of crisp lettuce
Authors: WURR D. C. E. , FELLOWS JANE R. , GRAY D. , STECKEL JOYCE R. A. 
Published: February 2008

SUMMARYSeed crops of crisp lettuce were produced in three years with and without gibberellin 4 plus 7 (GA4+7) application to the young seedlings. The effects on seed and seedling characters and field performance of harvesting seed at different times, either by shaking out mature seed or by ‘windrow’ harvests, were assessed.Differences between treatments in seed and seedling characters within any one year were relatively small although those treatments producing large seed gave large seedlings and those giving uniform seed gave uniform seedlings. There were no important effects of seed production treatments on field characters in any one year. However, when different years of seed production were compared directly there was a large effect of year of production on seedling establishment and the size and uniformity of seedlings. Application of GA4+7 resulted in heavier and more uniform seedlings in two of the three years. The results suggest that major differences between commercial seedlots occur as a result of differences in the environment rather than in the technique of seed production.
The effect of barley yellow dwarf virus on the amino acid composition of spring wheat
Authors: AJAYI OLUPOMI 
Published: February 2008

SUMMARYLeaf extracts of barley yellow dwarf virus‐infected and healthy spring wheat (cv. Highbury) plants at three growth stages were analysed by gas liquid chromatog‐raphy to determine their free amino acid content. Eleven free amino acids were identified. Virus infection increased the total amino acid content of sampled leaves at each growth stage but more so at the later stages. Alanine and glutamine were consistently present in greater amounts in infected than in healthy leaves at all three growth stages.
Self‐ and open‐pollination as factors influencing seed quality in leek (Allium porrum)
Authors: GRAY D. , STECKEL JOYCE R. A. 
Published: February 2008

SUMMARYThe effect of self‐pollination compared with open‐pollination on leek seed weight, and subsequent seedling emergence and growth were observed for two years of seed production.Open‐pollination gave higher mean seed weights and lower seedling losses during plant establishment than self‐pollination. Depending upon the year, the individual plant and pollination method, between 2. 4 and 56.6% of the variation in seedling weight c. 4–5 wk after sowing under controlled conditions was accounted for by differences in seed weight and time of seedling emergence. In 1984 but not 1983, a greater proportion of the variation in seedling weight was accounted for by seed weight and time of seedling emergence in open than self‐pollinated seeds.
Inheritance of a dwarf seed stalk character in onion
Authors: HOROBIN J. F. 
Published: February 2008

SUMMARYResults are reported of crossing a dwarf seed stalk line (mean height 44.8 cm) from Israel with five inbred lines of the Rijnsburger type each having normal tall seed stalks (mean heights 83.1–105.9 cm). The seed stalk height of F1 generations from these crosses was slightly greater than that of the Rijnsburger parents but segregation occurred in the F2 giving plants which could be considered ‘dwarf’ and ‘normal’ with respect to seed stalk height. Selfing individual F2‘dwarf’ plants produced F3 progenies whose mean heights were in the dwarf range, and were significantly correlated with those of their F2 parent. The results obtained in the F2 and F3 families suggest that although a major recessive gene for dwarfness may be present, substantial minor gene and environmental variation is also involved.
Effect of temperature on the population dynamics of three Dalbulus leafhopper species
Authors: MADDEN L. V. , NAULT L. R. , HEADY S. E. , STYER W. E. 
Published: February 2008

SUMMARYAdult survival and fecundity of three Dalbulus leafhopper species were determined at constant temperatures of 20, 23, 26 and 29°C. Survival was measured by quartiles (i.e. time to 75%, 50% and 25% survival) and estimated parameters of the Weibull model fitted to the survival distributions. D. gelbus lived as long or significantly (P= 0.05) longer than the other species at all temperatures. D. maidis (the corn leafhopper) had survival times equal to or significantly shorter than D. elimatus (the Mexican corn leafhopper) at all temperatures except 29°C where D. maidis lived the longest. The shape of the survival curves did not vary among species or change with temperature.The fecundity of D. gelbus, as measured by the average number of eggs laid per female per generation, was equal to or significantly lower than the other species at all temperatures. D. maidis and D. elimatus had similar fecundity at all temperatures except 29°C, where D. maidis produced significantly more eggs. The mean development time from egg to adult declined with temperature between 17 and 29°C. At all temperatures, D. maidis developed the fastest, D. gelbus the slowest, and D. elimatus was intermediate. The results can be explained on the basis of the geographic distribution, plant host species, and life‐history strategies of the leafhoppers. Models for describing the population dynamics of leafhoppers are evaluated and discussed.
The collection and selection in Europe of isolates of Phragmidium violaceum (Uredinales) pathogenic to species of European blackberry naturalised in Australia
Authors: BRUZZESE E. , HASAN S. 
Published: February 2008

SUMMARY Phragmidium violaceum is a rust fungus with potential for the biological control of European blackberry (Rubus fruticosus) in Australia. The collection, selection, purification and multiplication in Europe of isolates of the rust is described. Species of European blackberry naturalised in Australia showed different levels of susceptibility when inoculated with a pool of 15 isolates highly pathogenic to Rubus procerus. Selection of individual isolates on the four most widespread blackberry species showed that only two of the isolates would be required to obtain the best attack on these four species.