bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution between parts of the main shoot and the tillers of photosynthate produced before and after anthesis in the top three leaves of main shoots of Hobbit and Maris Huntsman winter wheat
Authors: THORNE G. N. 
Published: February 2008

SUMMARYThe top three leaves of main shoots in crops of Hobbit and Maris Huntsman winter wheat were exposed to 14CO2 at 22 and 16 days before and at 10 days after anthesis in 1978. The distribution of the 14C recovered in whole plants at anthesis and at maturity was measured. There was negligible loss of 14C between these two times, but some redistribution.The percentage in the tillers was negligible when the flag leaf (leaf 1) was exposed to 14CO2, and otherwise less than 12% except for 14C absorbed by the third leaf at 16 days before anthesis, when it averaged 26% but was very variable. When 14C was supplied before anthesis, about 20% reached the grain whichever leaf had been supplied. The ear structures contained about 10% of that absorbed by the third leaf and 35% of that absorbed by the flag or second leaf. When 14C was supplied after anthesis, the amounts reaching the grain from the different leaves were: flag 82%, second 68%, third 56%. Most of the remainder was in the stem. The exposed leaf never retained more than 6%.The amount of 14C that moved from the stem to the grain between anthesis and maturity was about 50% greater in the semi‐dwarf variety Hobbit than in Maris Huntsman. There was no significant varietal difference in the percentage of post‐anthesis 14C reaching the grain. The ear structures of Hobbit contained about a third more 14C than those of Maris Huntsman. An additional 90 kg N ha‐1, which increased grain yield by 46%, had negligible effects on the distribution of 14C.
Sensitivity to metalaxyl of Phytophthora infestans populations in potato crops in south‐west England in 1980 and 1981
Authors: CARTER G. A. , SMITH R. M. , BRENT K. J. 
Published: February 2008

SUMMARYA laboratory test was developed to assess the sensitivity of field populations of Phytophthora infestans to metalaxyl. Discs of potato leaf tissue were floated upon solutions of the fungicide at different concentrations and inoculated with spores. The extent of symptom development was noted after incubation under standard conditions for 5–6 days. In preliminary experiments growth of isolates of P. infestans obtained from culture collections was severely inhibited in discs treated at 2 μg/ml. By contrast the development of an isolate obtained from a crop in Eire in which blight control with metalaxyl had failed, and known to be markedly less sensitive in vitro, was unaffected in discs treated at 100 μg/ml.During the summer of 1980, 234 samples of P. infestans were obtained from 20 sites in south‐west England, 10 of which had received sprays containing metalaxyl and 10 of which had not. All samples were sensitive to metalaxyl applied at 2 μg/ml. In 1981, 35 sites within the same area, 30 of which had received sprays containing either metalaxyl or ofurace (a related fungicide), were similarly surveyed. Most of the 79 samples of P. infestans examined proved sensitive and at all sites the amount of blight was small. However, at three sites, including one not treated with acylalanine fungicides, strains were found which were unaffected by 100 μg/ml metalaxyl in leaf disc tests. These findings are discussed in relation to the development of resistant blight in other areas and to the use of fungicide mixtures.
Properties of a tomato isolate of Pelargonium zonate spot virus
Authors: GALLITELLI D. 
Published: February 2008

SUMMARYA manually transmissible virus isolated from tomato plants with stunting, unfruitfulness, malformation and yellow rings and line patterns of the leaves was indistinguishable from Pelargonium zonate spot virus (PZSV) in biological, physico‐chemical and serological properties. The tomato isolate (PZSV‐T) of PZSV was seed transmitted in Nicotiana glutinosa and was detected in the pollen of this host. In sap of N. glutinosa PZSV‐T lost infectivity after diluting 10‐1 to 10‐2, heating for 10 min at 35 to 40 °C or storage at 25 °C for 7 h.Virus particles were quasi‐spherical with a diameter ranging between 25 and 35 nm with a modal value of 29 nm. Particles sedimented as three components (TV, MV and BV) with sedimentation coefficients of 80S (TV), 90S (MV) and 118S (BV); component BV is probably an aggregate of TV. Particles were unstable in CsCl and CS2SO4 but formaldehyde‐stabilised particles banded at a common density of 1–268 g/cm3 in Cs2SO4. Particles contained a single protein species with mol. wt of c. 23000 and c. 18% single stranded RNA present as two species with mol. wts of c. 1.25 × 106 (RNA‐1) and 0.95 × 106 (RNA‐2). Mixtures of RNA‐1 + RNA‐2 were infectious and this infectivity was not enhanced by the addition of coat protein. Virus particles had a Tf (mid point of extinction when heated) of 63 °C and were readily dissociated by 0.1% SDS.PZSV‐T was serologically unrelated to alfalfa mosaic and to 32 isometric viruses including five ilarviruses. Some properties of PZSV resemble those of ilarviruses but others are sufficiently different to suggest that it may not be a member of this virus group.
Lamium mild mosaic virus: a virus distantly related to broad bean wilt
Authors: LISA V. , LUISONI E. , BOCCARDO G. , MILNE R. G. , LOVISOLO O. 
Published: February 2008

SUMMARYLamium mild mosaic virus (LMMV) was compared with some strains of broad bean wilt virus (BBWV). It differed somewhat in host range from BBWV; serologically, it was only distantly related to four strains of BBWV, all belonging to serotype I, but no reaction was detected with serotype II. BBWV and LMMV were not serologically related to six comoviruses. Like BBWV, LMMV sedimented in three components and the two viruses were morphologically indistinguishable, but LMMV had more slowly migrating RNAs and coat proteins. No distinctive pathological changes were seen in LMMV infected cells.It is proposed that LMMV be considered a distinct virus from BBWV but included with it in a new group of plant viruses.
Studies of the cereal cyst‐nematode, Heterodera avenae under continuous cereals, 1975–1978. II. Fungal parasitism of nematode females and eggs
Authors: KERRY B. R. , CRUMP D. H. , MULLEN L. A. 
Published: February 2008

SUMMARYThe development and fungal parasitism of Heterodera avenae females and eggs on susceptible cereals was studied from 1975 to 1978 in a sandy loam soil. Despite the production of many females on the roots nematode numbers declined in two years (1975 and 1978), and it is female survival and fecundity and not female numbers which often limit H. avenae multiplication.Fungal parasites may totally destroy females on roots or result in the formation of small cysts which are often empty. Fecundity is reduced and many eggs may became infected. Parasitism of females and eggs was decreased and nematode multiplication was increased in soil treated with formalin (38% formaldehyde) at 3000 litres/ha, but because it is nematicidal and fungicidal interpretation of the effects of the sterilant are difficult. Formalin has a greater effect on H. avenae multiplication in wet summers when fungal parasites, particularly Nematophthora gynophila are more active.Parasitised females which may be destroyed in about 7 days are fragile and difficult to extract from soil. Rates of parasitism tend to be underestimated. Approximately 60% of the females which failed to form cysts containing eggs can be accounted for by N. gynophila and Verticillium chlamydosporium.Fungal parasitism is therefore the major factor in limiting the multiplication of H. avenae.
Weather limitations on the application of dinoseb‐in‐oil for cane vigour control in raspberry
Authors: MACKERRON D. K. L. , LAWSON H. M. 
Published: February 2008

SUMMARYData on crop growth suggested that only 8 days are available for timely spraying of dinoseb‐in‐oil for control of cane vigour in raspberry in east‐central Scotland. Crop records were linked with meteorological data to indicate the dates between which this 8‐day period might fall. The meteorological data were then examined to assess the probability and likely duration of conditions suitable for spraying within the period when the crop is amenable to the spray treatment.The results indicated that unfavourable weather conditions may severely restrict the opportunities available for spray application by conventional equipment, the main limitation being high wind speed. The likelihood of rain after application putting the spray treatment at risk was found to be low.The infinitely compound Poisson distribution was found to be suitable for graduating the observed frequency distributions of suitable spraying conditions. Diagrams of frequency distributions were produced which can be used to assess the spraying capacity required to ensure timely application over the total area of a grower's plantations. It is suggested that the approach used in this investigation could be satisfactorily applied to a wider range of crops and spraying operations.
Development of streak virus‐resistant maize populations through improved challenge and selection methods
Authors: SOTO P. E. , BUDDENHAGEN I. W. , ASNANI V. L. 
Published: February 2008

SUMMARYTolerance to maize streak virus (MSV) was found and rapidly incorporated into high yielding maize populations for the tropics. Methods were developed for vector propagation and rapid accurate screening of many accessions for virus tolerance in large screenhouses. Tolerance was found in only two accessions and at low frequencies. Further refinements enabled field evaluation for virus tolerance to be combined with high agronomic performance. The tolerance found is simply inherited and was fixed rapidly in breeding. Non‐strain specific tolerance was sought by collecting vectors and different indigenous host grasses from a wide area. The tolerance developed was sufficiently high hardly to affect yield of infected plants. It provided epidemiological or field resistance by reducing disease incidence to insignificance under natural conditions. This tolerance and field resistance has proved effective in several countries of East, West and southern Africa. Varieties derived from this work are now being promoted in Nigeria, and they have potential application elsewhere in the lowland tropics.
Use of a sequential probability ratio test to assess sib content in Brassica oleracea
Authors: SMITH P. , WILLS A. B. 
Published: February 2008

SUMMARYSeed lots of F1 hybrids of Brassica oleracea are unmarketable if they contain too many sibs. The modified sequential probability ratio test (SPRT) proposed by Whitehead (1981) can be used to determine whether a hybrid seed lot meets specified quality standards for sib content and to estimate the actual proportion of sibs. It is more economical in testing than a single‐sample procedure of equal accuracy and is particularly suited for use with electrophoretic methods of sib recognition. A computer program has been written to produce control charts, for a range of test standards, for direct plotting of results.
A study of glands on cotton responsible for the high pH and cation concentration of the leaf surface
Authors: ELLEMAN CAROLE J. , ENTWISTLE PHILIP F. 
Published: February 2008

SUMMARYGroups of hygroscopic microcrystalline particles were found on the leaf surface of cotton, Gossypium hirsutum and were shown to be produced by glands in the epidermis. The glands were hydathode‐like, about 20 μm in diameter by 25 μm long, with swollen, rounded, apices. They secreted high concentrations of magnesium and potassium and some sulphur and calcium, as indicated by X‐ray microanalysis, onto the leaf surface. The proportions of elements present in gland secretions could be altered by changing the root environment of the plant. When the microcrystalline particles were removed and made up in distilled water the resulting solution had a pH of 10.2. It was established that the glands are responsible for the high pH and cation concentrations on the cotton leaf surface. The morphology and structure of the glands was investigated by light and electron microscopy and their possible function is discussed.
Varietal differences in uptake of 32P labelled phosphate in clover plus ryegrass swards and monocultures
Authors: GOODMAN P. J. , COLLISON M. 
Published: February 2008

SUMMARY Lolium perenne cv. S.23, L. multiflorum cv. RvP, and Trifolium repens cvs S.184 and Olwen, were grown in mixed sward and monoculture during 1979. Whereas in mixtures grass roots absorbed more 32P than clover roots, in monoculture clover generally absorbed more 32P than grass roots. This showed that grass was a very strong competitor for uptake in mixed swards.Clover and grass monocultures absorbed most 32P from 10 or 15 cm depth in the soil, while grass in mixtures absorbed most 32P at 22.5 cm depth.Comparing varieties, in monocultures in June, Olwen was most active in absorbing 32P at 15 cm. In August, Olwen absorbed more at 15 cm and 22.5 cm than S.184 or the grass varieties. Differences in absorption depth between varieties were less in mixtures than in monocultures. S.23 absorbed more 32P in the late season than RvP, both in monoculture and in mixtures. Thus Olwen differed from S. 184 in depth and timing of uptake, whilst S.23 differed from RvP in time of uptake. Such varietal differences could be exploited by manipulation of depth and timing of fertiliser application to increase the precision of sward management.
The effect of barley yellow dwarf virus on honeydew production by the cereal aphids, Sitobion avenae and Metopolophium dirhodum
Authors: AJAYI OLUPOMI , DEWAR A. M. 
Published: February 2008

SUMMARYIndividual S. avenae and M. dirhodum excreted significantly fewer droplets of honeydew on plants infected with BYDV than on healthy plants. S. avenae excreted less honeydew on the ears than on the leaves of wheat. M. dirhodum excreted less than S. avenae on the leaves. The size of honeydew droplets increased with the age of aphids but was not affected by BYDV infection. Possible reasons for the observed effects of BYDV on honeydew excretion are discussed.
A method of using the proportions of undamaged carrots or parsnips to estimate the relative population densities of carrot fly (Psila rosae) larvae, and its practical applications
Authors: WHEATLEY G. A. , FREEMAN G. H. 
Published: February 2008

SUMMARYThe plant‐to‐plant distribution of carrot fly damage was studied on carrots and parsnips in field and microplot experiments. The observed data were well‐fitted by the relationship In (–In q) = In L+ constant, where q is the proportion of undamaged roots and L is the number of larval mines in a sample and is proportional to the number of associated larvae, N. Hence, if N1 and N2 are the numbers of larvae at two levels of infestation on one occasion, the relative numbers present, N2:N1 are estimated by In q2: In q1 In this way the relative efficiencies of insecticide treatments can be determined within an experiment from only q1 and q2 and compared between occasions. A nomogram relating q1, q2 and treatment efficiency is provided. The method can also probably be used to compare the relative susceptibilities of host‐plant cultivars to carrot fly attack.Guidance is given on the sample sizes needed to estimate q within 95% confidence limits and constraints on the application of the method are stated. An appropriate statistical procedure for analysing data sets on carrot fly infestations is by analysis of deviance and an example is given in an Appendix. The principles described can probably be adapted to other crop/pest problems.
Germination and growth of single‐pustule isolates of Erysiphe graminis tolerant and sensitive to tridemorph and ethirimol
Authors: LAWS F. A. , WALMSLEY‐WOODWARD DIANNE J. , WHITTINGTON W. J. 
Published: February 2008

SUMMARYThe germination and colony growth of single‐pustule Erysiphe graminis isolates tolerant and sensitive to tridemorph and ethirimol was studied on glass slides and on leaf segments sprayed with tridemorph or left untreated.In the absence of the fungicide, neither tridemorph‐ nor ethirimol‐tolerant isolates differed from the sensitive in germination or colony growth. Germination percentages of all isolates were depressed by high temperature and low humidity, although some isolates grew well in less than optimum conditions. Differences between ethirimol‐ and tridemorph‐tolerant and sensitive isolates for colony size on untreated plants of various cultivars reflected differences in virulence to the host rather than fungicide tolerance.The presence of tridemorph retarded the growth rate of colonies of tolerant and sensitive isolates, but the germination of tridemorph‐tolerant isolates was greatly stimulated by low concentrations of tridemorph (50 mg/litre) and was less depressed than that of the sensitive isolates by high concentrations (200 mg/litre).
Chemical suppression of the sexual stage of Leptosphaeria maculans on oil‐seed rape and turnip seed crop straw
Authors: HUMPHERSON‐JONES F. M. , BURCHILL R. T. 
Published: February 2008

SUMMARYA selection of fungicides, herbicides and surfactants and urea were tested for their effect on the production of pseudothecia and ascospore release of Leptosphaeria maculans present on oil‐seed rape straw and turnip seed crop straw. The fungicides ethyl mercury phosphate, triarimol, fenarimol, carbendazim, tridemorph and benomyl, each at 1 g/litre, the herbicides dinoseb and diquat, each at 10 g/litre the surfactants Bradasol, Cetrimide, Deciquam 222, Hyamine 1622 and Maxonol N, each at 50 g product/litre, and urea at 150 g/litre, applied to straw before pseudothecia had formed were more than 90% effective in preventing further development. These chemicals were also effective in preventing further ascospore production when applied to straw bearing mature pseudothecia but only dinoseb and urea prevented the release of mature ascospores. The results suggest that it may be possible to break the life cycle of L. maculans by chemical treatment and thereby obviate the need for subsequent control measures.
Fungicide programmes for the control of spur blight, powdery mildew and grey mould on raspberry
Authors: SWAIT A. A. J. 
Published: February 2008

SUMMARYFive sprays of dichlofluanid (0–1% a. i.) reduced spur blight (Didymella applanata) on canes and powdery mildew (Sphaerotheca macularis) on fruit more than five sprays of captan (0–1% a. i.). Omission of the first three applications resulted in little increase in disease but when the fourth (full bloom) application also was omitted the incidence of disease was comparable with that on untreated plants. The final (fruitlet stage) application did not further reduce disease incidence. Five sprays of dichlofluanid reduced grey mould (Botrytis cinerea) on stored fruit more than five sprays of captan. There was an increase in grey mould with progressive reductions in the number of sprays. Incidence on canes was slight and was unaffected by treatments.A programme of five dichlofluanid sprays applied at 14‐day intervals until c. 2 wk before harvest and supplemented by a single early full bloom spray of either dinocap (0–025% a. i.), binapacryl (0–05% a. i.), triforine (0–025% a. i.), benomyl (0–025% a. i.) or replaced by benomyl (0–025% a. i.) all halved both the number of fruits infected by powdery mildew and the number of spur blight lesions on canes, compared with unsprayed controls.Six applications of any of the following fungicides at 7‐day intervals from 23 May until 29 June 1977 reduced powdery mildew incidence on fruit, the last fungicide being particularly effective: dinocap (0–0125%), dichlofluanid (0–075%), binapacryl (0–025%), triforine (0–0125%), bupirimate (0–0075%), ditalimfos (0–01875%) and fenarimol (0–0036%). Only triforine and bupirimate reduced the incidence of mildew on shoots. Dichlofluanid, binapacryl, triforine and fenarimol all reduced the amount of spur blight on canes. The largest fruit occurred on plants sprayed with bupirimate, ditalimfos and fenarimol, and late ripening was associated with triforine treatments.
Invasion and development of juveniles of Globodera pallida in hybrids of Solanum vernei x S. tuberosum
Authors: PHILLIPS M. S. , FORREST J. M. S. , FARRER LINDA A. 
Published: February 2008

SUMMARYInvasion and development of Globodera pallida (Pa 2) were investigated in the susceptible cultivar Pentland Crown and in two Solanum tuberosum S. vernei clones, 8917 b (3) and 12380 abc (2) with respective susceptibilities of 10% and < 1%. The numbers of juveniles per unit length of main root of Pentland Crown and 8917 b (3) did not differ, but the numbers found in the highly resistant clone 12380 abc (2) were significantly lower at all sampling dates except the last. Development of juveniles was substantially retarded in 12380 abc (2) and there was a higher ratio of males to females in both the resistant clones.It is suggested that reduced invasion and establishment can contribute to resistance and tolerance of potatoes to potato cyst‐nematode.
Selection of a rapidly maturing population of Globodera rostochiensis by continuous cultivation of early potatoes in Ayrshire, Scotland
Authors: HOMINICK W. M. 
Published: February 2008

SUMMARYDevelopment of three G. rostochiensis populations was compared after 2, 3, 4, 5 and 13 wk at 12 and 15 °C on cv. Pentland Crown. The Jameston Farm (JF) and Skelmorlie populations originated from Ayrshire, Scotland, the former where early potatoes are grown annually, the latter from a farm where potatoes are grown in a conventional manner. The Feltwell population was originally from Norfolk, England. At 12 °C, nematodes from the JF population penetrated roots and developed more quickly than nematodes from the other populations. The JF population also produced the most cysts, which were the largest and contained most embryonated eggs. At 15 °C, differences between the populations were less marked, but JF nematodes invaded roots quickest and produced cysts with most eggs. These results are consistent with the hypothesis that the annual practice of early planting and harvesting to control losses caused by G. rostochiensis in Ayrshire is selecting a nematode population adapted genetically to the procedure.