bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of variation in temperature and light intensity at different times on growth and yield of spring wheat
Authors: FORD MARGARET A. , THORNE GILLIAN N. 
Published: February 2008

SUMMARYSpring wheat grown in pots outdoors was transferred to growth rooms for various periods to study the effect of increasing the temperature from 14‐4 to 20‐3 oC (Expt 1) or from day/night values of 15‐0/15‐2 to 20‐0/15‐2 oC (Expt 2) and of increasing the amount of visible radiation in a 16 h day from 424 to 792 J cm‐2 (Expt 1) or 374 to 740 J cm‐2 (Expt 2). There were no interactions between temperature and radiation.In Expt 1 neither the increase in temperature nor extra radiation, applied for 14 days immediately after the appearance of double ridges on the stem apex, or 14 days later, increased grain yield at maturity. Warmth early, but not late, increased dry weight, leaf area and the number of floret primordia immediately after treatment, but these effects had disappeared by anthesis, 30 days later. Dry weight but not leaf area was increased by extra radiation but the effects had disappeared 2 wk after treatment.An increase in temperature imposed for 16 days starting 5 or 21 days after anthesis (Expt 2) increased dry weight of the ear and decreased that of the rest of the plant immediately after treatment, and decreased leaf area at all times. When plants from the two temperatures were put together in the same conditions, ear growth of plants that had been in the warm was slower than that of plants from the cold treatment, so that the difference in ear weight observed after 16 days of treatment reversed and grain yield was decreased by warmth applied in either period; the component of yield decreased by warmth was grain size. Additional radiation in either post‐anthesis period increased dry weight of all parts of the plant and had negligible effects on leaf area. Final grain yield was increased by c. 15% because the individual grains were larger. Early treatment also increased grain number slightly. The effects of treatment during the two post‐anthesis periods were similar in size, and additive.
The size and shape of plots in sugar‐beet experiments
Authors: JAGGARD K. W. 
Published: February 2008

SUMMARYUniformity of root yield and plant density of sugar beet was assessed on four areas each of 250 small plots‐two in each of the years 1969 and 1970. Plots from which 2–5‐100 m2 of crop was harvested from the centre rows were constructed and their coefficients of variation calculated. Coefficient of variation decreased as harvested area increased, but little additional accuracy was achieved by harvesting more than 40 m2. Plots drilled‐to‐a‐stand appeared no more variable in root yield or plant density than carefully hand‐singled plots.
The induction of leaf‐roll galls by the apple aphids Dysaphis devecta and D. plantaginea
Authors: FORREST J. M. S. , DIXON A. F. G. 
Published: February 2008

SUMMARY Dysaphis devecta causes the leaves of its host plant to roll laterally whereas D. plantaginea causes them to roll longitudinally. Both species of aphid are phloem feeders. D. devecta prefers to feed on the smaller veins in the lamina whereas D.plantaginea chooses the midrib. However, groups of D. devecta or D. plantaginea confined to the stem of an apple seedling induced young leaves several centimetres away to develop leaf rolls characteristic of each species. A single larva of D. devecta or D. plantaginea can induce a leaf‐roll or a stem‐bend on an apple seedling within 24 h. It is suggested that characteristic abnormalities in leaves attacked by D. devecta and D. plantaginea are caused by specific substances in the saliva of each aphid.
The role of the perennial stinging nettle, Urtica dioica, as a reservoir of beneficial natural enemies
Authors: PERRIN R. M. 
Published: February 2008

SUMMARYA wide range of natural enemies, including predators, parasites and entomophagous fungi were observed to feed on the stinging nettle aphid, Microlophium carnosum, populations of which increased rapidly in late April and early May. Patches of stinging nettles thus served as an important alternate feeding site for some beneficial natural enemies before pest aphids appeared on cultivated plants. Anthocoridae, Miridae and Coccinellidae were the most abundant specific predators sampled on nettles; only the Coccinellidae appeared to disperse over a defined period to other habitats. The hymenopterous parasites Aphidius ervi and Ephedrus lacertosus parasitized up to 10% of M. carnosum populations in June: two species of the fungus Entomophthora occurred spasmodically.Cutting patches of nettles in May or June had the most striking effect on the species and numbers of Coccinellidae. Cutting in mid‐June might increase the numbers and impact of natural enemies on nearby pest infestations.
Duration of effects of benomyl on growth and wilt (Verticillium dahliae) development in the strawberry, cv. Cambridge Vigour, in relation to time of inoculation
Authors: TALBOYS P. W. , FRICK E. L. , DAVIES MOIRA K. 
Published: February 2008

SUMMARYSingle doses of benomyl, 0–4 g/plant in 1972 or 0–04 g in 1973, were applied in 100 ml water to the surface of the soil in 12‐5 cm pots containing Cambridge Vigour strawberry plants, either before inoculation with Verticillium dahliae or at various times up to 56 days afterwards. Pre‐inoculation treatments were terminated by washing the potting medium from the roots at the time of inoculation and their effects on pathogenesis and growth were relatively small. Post‐inoculation treatments with benomyl prevented or suspended pathogenesis for at least as long as fungistatic activity could be detected in petiole segments by bioassay; this was for more than 150 days after the larger dose, 50–60 days after the smaller dose applied 7–28 days after inoculation and 30 days when applied 56 days after inoculation.There were no consistent differences in the uptake and persistence of benomyl in inoculated and non‐inoculated plants.Early post‐inoculation treatment caused some retardation of plant growth, but benomyl‐treated inoculated plants were generally comparable in size with similarly treated non‐inoculated ones, and much larger than untreated inoculated plants.Increasing the dose of benomyl applied to the soil apparently had little influence on the intensity of its effects but greatly increased their duration, probably because of the low solubility of the systemic chemical.
The response of various breeding lines of lettuce to beet western yellows virus
Authors: WATTS L. E. 
Published: February 2008

SUMMARYThe field occurrence of symptoms of beet western yellows virus (BWYV) disease in breeding lines of summer lettuce was studied in trials conducted from 1971 to 1974. No evidence of immunity was found in seventy cultivars and over 500 lines from ten crosses, but some lines, notably those with Little Gem as one parent, appeared to be less affected by the disease.When the number of plants showing symptoms was recorded on a weekly basis it was apparent that only minor differences existed in the response to infection. In the earlier maturing lines, 50 % of the plants exhibited symptoms within 16 to 20 days of hearting, and later maturing lines reached the same level of disease incidence within 7 to 16 days after hearting.The search for resistance should be widened to include wild species; strict selection techniques up to flowering time should also be used to increase field resistance in the present cultivars.
Storage characteristics of some vegetables and soft fruits
Authors: ROBINSON J. E. , BROWNE K. M. , BURTON W. G. 
Published: February 2008

SUMMARYRates of carbon dioxide production, in air and in 3 % 02, over a range of temperatures, were measured for over thirty commodities, and rates of evaporation, under known water vapour pressure deficit, measured for most of them. Optimum storage conditions in air for each commodity were determined. Storage life under these optimum conditions, and under the nearest practical approximation to them, was estimated. In most cases the optimum temperature is ooC, examples of exceptions being runner beans, cucumbers, potatoes, green peppers and tomatoes. The humidity should usually be high, 100 % r.h. often being optimal, particularly for leafy vegetables, provided the temperature is low. Commodities resistant to evaporation, however, such as the onion, may with advantage be stored at lower humidities, thus reducing the microbial hazards.
Screening potato clones for resistance to dry rot (Fusarium solani var coeruleum)
Authors: JELLIS G. J. 
Published: February 2008

SUMMARYA modification of the Boyd method is described in which cores of potato tissue are used instead of whole tubers. This reduces the space required for incubation, permits good control of the environment and eliminates the need to sacrifice valuable seed material. The method was used for testing the resistance of sixteen cultivars of potato on five occasions over two seasons.
The fumigation of seeds with methyl bromide
Authors: POWELL D. F. 
Published: February 2008

SUMMARYForty varieties of vegetable, cereal, fodder and grass seeds at 10, 13 and 16% moisture content were fumigated with methyl bromide at 10 and 18oC, to determine the maximum safe moisture content required to avoid unacceptable phytotoxicity. Dosages (concentration x time products) of 200 and 400 mg h/1 of technical and commercial methyl bromide were used and treated seeds were compared with controls in germination tests. Results were not consistent, but in c. 30 % of the comparisons lower moisture contents, lower temperature and lower dosage each resulted in better germination than the corresponding higher values. The reductions in germination of treated samples were usually less than 5 % and the overall average reduction was only 2.3%. This work showed that under controlled conditions the treatments are safe for most of the tested varieties of seed, but for some seeds, particularly white clovers, Agrostis and runner beans, the highest moisture content (16%) should be avoided.
Comparison of centrifugal and other methods for standardization of extraction of nematodes from soil
Authors: HARRISON JUDITH M. , GREEN C. D. 
Published: February 2008

SUMMARYThe extraction of many genera of nematodes from four different soil types by sedimentation, mobility, sieving and centrifuging was compared. All methods were found to extract similar numbers of nematodes. Centrifuging was the most versatile technique and the best for clay soils. Baerman sieving was generally poor and particularly so for sands and for the genus Tylen‐chorhynchus. Rotylenchus was the only genus of those identified that was extracted equally well by all techniques. Centrifugal extraction was selected as the routine method for surveys as it was effective on all soil types, was less likely to be subject to variation and, although poor for Longidorus, extracted a wider spectrum of nematodes.
Effects of variation in ear temperature on growth and yield of spring wheat
Authors: FORD MARGARET A. , PEARMAN I. , THORNE GILLIAN N. 
Published: February 2008

SUMMARYWheat plants were kept in a growth room at 15 oC from 7 days after an‐thesis until maturity and their ears were warmed to 20 or 25 oC for various periods. Continuous warming initially increased the growth rate of the ear and decreased that of the stem, but hastened senescence of the ear and decreased final grain yield by decreasing dry weight per grain. Warming the ears increased the movement of 14C and nitrogen to them from the leaves and stem during the early stages of grain growth but decreased it later. Warming the ears for only the first 10 or 20 days also hastened ear senescence; grain yield decreased progressively with increase in duration of the warm period. All effects were greater at 25 than at 20 oC.The effects of changing ear temperature from 15 to 20 oC were independent of the temperature of the rest of the plant. Altering the humidity of the air around the ears by 4–7 mb at constant temperature had no effect on ear growth or senescence.Warming all of the plant except the ears from 15 to 20 oC increased ear growth slightly during early grain growth and decreased it later, irrespective of ear temperature: stem dry weight, leaf area and net photosynthetic rate of flag leaves and green stems were decreased and dark respiration rate of stems was increased.
Cytological techniques for use in apple breeding
Authors: LESPINASSE Y. , ALSTON F. H. , WATKINS R. 
Published: February 2008

SUMMARYDetails are given of improved cytological squash techniques for mitotic and meiotic counts which are especially useful in apple breeding. The cytological characteristics of scion varieties (including triploids such as the recently named Suntan), apple rootstocks (including tetraploids), and second backcross progenies of the mildew resistant species Malus hupehensis (2n= 51) to the cultivated apple (in which most seedlings were found to be diploid) are discussed with reference to their implications for apple breeders.
The control of peach leaf curl (Taphrina deformans) with Off‐Shoot T
Authors: BURCHILL R. T. , FRICK E. L. , SWAIT A. A. J. 
Published: February 2008

SUMMARYEffective control of peach leaf curl disease (Taphrina deformans) was obtained with two winter sprays of a 63 % mixture of fatty alcohols (Off‐Shoot T) applied at 5 % a.i. Phototoxicity was insignificant.
The reaction of wheat genotypes to Septoria tritici
Authors: BROKENSHIRE T. 
Published: February 2008

SUMMARYSeedling leaves, flag leaves, culms and heads of wheat genotypes were evaluated under glasshouse and field conditions for reaction to Septoria tritici. Parameters used for resistance screening were the incubation and latent periods, disease and sporulation levels, and 1000 grain weight.Significant correlations were obtained between reactions of different plant organs and between field and glasshouse tests; significant interspecific and intraspecific differences occurred for all screening parameters. Triticum aestivum varieties showed a wide range of disease reaction ranging from the high resistance of Elite Lepeuple, Maris Dove, Maris Ensign, Chalk and Tommy to the high susceptibility of Rothwell Sprite, Sovereign, Cardinal, Maris Ranger and Maris Templar.
Mildew reinfection in adjacent and separated plots of sprayed barley
Authors: BAINBRIDGE A. , JENKYN J. F. 
Published: February 2008

SUMMARYIn latin square experiments in 1973 and 1974, reinfection of sprayed barley, by mildew (Erysiphe graminis f.sp. hordei) was decreased by widely spacing the plots. In 1974, when yields differed between plots which were either contiguous or separated, the results suggested different times to spray for best yield increase.
The effect of resistance to Amphorophora rubi in raspberry (Rubus idaeus) on the spread of aphid‐borne viruses
Authors: JONES A. T. 
Published: February 2008

SUMMARYThe effectiveness of resistance to the aphid Amphorophora rubi in restricting the spread of aphid‐borne viruses was assessed in a field experiment using six genotypes of red raspberry. In one block of the experiment, the genotypes alternated with rows of virus‐infected Mailing Jewel raspberry, and in the other they alternated with virus‐free Mailing Jewel. During 4 years, the numbers of A. rubi and the amount of 52V virus spread in the two blocks were similar, suggesting that this virus was mostly introduced from outside the plots.Lloyd George and Mailing Jewel raspberry became heavily infested with A. rubi and were rapidly infected with raspberry leaf mottle, raspberry leaf spot and 52V viruses. Glen Clova and Norfolk Giant raspberry, which contain minor genes for resistance to A. rubi, were infested with fewer A. rubi and virus spread more slowly in these cultivars. A. rubi were rare on Mailing Orion and an East Mailing raspberry selection (888/49) which have genes A1 and A10 respectively for resistance to A.rubi, and these plants remained largely free of virus. The role of minor and major gene resistance to A. rubi in restricting virus spread is discussed.A few Macrosiphum euphorbiae and Myzus ornatus were recorded on several of the raspberry genotypes.
The relative performance of white clover genotypes with rhizobial and mineral nitrogen in agar culture and in soil
Authors: MYTTON L. R. 
Published: February 2008

SUMMARYVegetative propagules of adult plants of white clover grown in agar culture show a better agreement with the performance of adult plants grown in soil than that previously reported of nodulated seedlings. This suggests that, whilst results obtained from the inoculation of seedlings can only be extrapolated to other situations with great caution, laboratory techniques which allow nitrogen fixation assessments to be made on adult plants may be useful in predicting performance under more natural conditions.The growth of vegetative propagules of mature plants dependent on rhizo‐bium fixed nitrogen was also compared with propagules receiving abundant inorganic nitrogen. In agar culture there were no differences in yield between nitrogen sources, indicating that the symbiotic associations could fix sufficient nitrogen for growth under these relatively restrictive conditions. In soil, however, only the slower genotypes came near to providing sufficient nitrogen from symbiosis to sustain their potential yield as measured from their growth with inorganic nitrogen. The more vigorous the genotype the greater was the short‐fall in nitrogen supplied by the rhizobium association. Joint regression analysis showed that any apparent interactions between plant genotypes and the source of nitrogen was a function of the genotypes' potential growth rate. The importance of quantifying nitrogen fixation in relation to the growth potential of the host genotype is emphasized, and the need, in legume breeding programmes, for simultaneous selection of host and rhizobium is discussed.
Studies on plant growth‐regulating substances. XXIX. The plant growth‐retarding properties of certain quaternary ammonium halides
Authors: CHAMBERLAIN VALERIE K. , CHAMBERLAIN K. , WAIN R. L. 
Published: February 2008

SUMMARYThe plant growth‐retarding activity of a series of N‐methyl‐N‐chloro‐alkyl‐pyrrolidinium and ‐piperidinium halides has been measured using wheat and barley seedlings and dwarf bean plants. Some of these compounds possess activity comparable to that of 2‐chloroethyl‐trimethyl‐ammonium chloride (CCC).The activities of twenty‐four quaternary halides of pyridine, N‐methyl‐pyrrolidine and N‐methylpiperidine, each possessing a chlorinated benzyl group, have also been determined in the wheat seedling and dwarf bean tests. Many of these compounds were active and activity could be correlated with the substitution pattern in the benzyl group.
Field and glasshouse experiments on the control of potato mop‐top virus
Authors: COOPER J. I. , JONES R. A. C. , HARRISON B. D. 
Published: February 2008

SUMMARYField observations during 3 yr on a stock of potato cv. Red Craigs Royal partially infected with potato mop‐top virus (PMTV) confirmed that the virus was passed by an infected mother plant to only a proportion of its progeny tubers, and showed that in this cultivar symptomless plants gave rise only to symptomless progeny. The elimination of PMTV from stocks can therefore be greatly accelerated by removing symptom‐bearing plants. Infected potato tubers were not freed from PMTV by treating them at 37 °C for up to 8 wk. Treating ‘seed’ tubers bearing powdery scabs that contain PMTV‐carrying resting spores of Spongospora subterranea with formaldehyde or organo‐mercurial fungicide greatly decreased PMTV establishment when the tubers were planted in previously uninfective soil, but fumigation with 2‐aminobutane was ineffective.Decreasing the pH of infective soil to 5‐0 by applying sulphur greatly decreased the infection of potato cv. Arran Pilot with PMTV and S. subterranea in field experiments, but this treatment did not eliminate either; when the pH of treated soil was raised the transmission of PMTV resumed. Treating infective soil with a range of fungicides greatly decreased the infection of Nicotiana debneyi bait seedlings in glasshouse experiments but only calomel at 75 kg/ha controlled spread of PMTV and 5. subterranea to potato in field experiments. In other field experiments, applying zinc frit, zinc sulphate or zinc oxide to infective soil greatly decreased the spread of both to potato. The amount of zinc required increased with increase in clay content of the soil. However, treatment with zinc compounds did not eliminate PMTV‐carrying vectors from soil, and when treated soil was diluted with autoclaved soil many of the bait seedlings planted in the mixture became infected. The zinc frit was phytotoxic because of its boron content but zinc sulphate and zinc oxide caused little or no decrease in tuber yield. The zinc content of potato tubers was increased but not doubled in zinc‐treated plots, and during the first year after treatment the zinc content of topsoil decreased greatly. The zinc content of ryegrass grown after potatoes was greater than of potato tubers but did not reach a level considered dangerous to livestock. Treatment of soil with sulphur, zinc oxide or calomel may be useful for small plots used in the early stages of propagation of virus‐tested potato clones where there is risk of infection with PMTV.
Studies on plant growth‐regulating substances. XLII. Abscisic acid as a genetic character related to drought tolerance
Authors: LARQUÉ‐SAAVEDRA A. , WAIN R. L. 
Published: February 2008

SUMMARYAbscisic acid levels were measured in turgid or wilted detached leaves from maize and sorghum seedlings. Lines, cultivars and hybrids known to exhibit different abilities to withstand water stress were compared. The leaves of those tolerant to drought were shown to contain substantially more free abscissic acid. The effect was more clearly shown by sorghum than by maize. The results are discussed in relation to the physiology of drought tolerance.
Agropyron repens ‐ allelopathy?
Authors: Sagar G. R. , Ferdinandez D. E. F. 
Published: February 2008

ABSTRACTFollowing the work of Becholtz and Bandeen, a series of glasshouse experiments was made to examine the effects of root‐zone interference between Agropyron repens and wheat. In a solution‐culture experiment the reduction in growth of wheat due to the presence of A. repens could be largely corrected by increasing the nutrient supply in the solution. In similar studies but using soils, the depression of growth of wheat could not be corrected. Foliage applications of nitrogen to wheat plants grown with A. repens had no effect. Using a split‐pot technique it was found that the part of the root system of wheat growing in the same medium as the rhizomes and roots of A. repens was very severely suppressed. These results will be discussed.
Varietal differences in the susceptibility of Brussels sprouts to lepidopterous pests
Authors: DUNN J. A. , KEMPTON D. P. H. 
Published: February 2008

SUMMARYThe attack by cabbage caterpillars on open‐pollinated cultivars of Brussels sprouts at Wellesbourne was recorded approximately weekly from July to October in 1973 and 1974. The red‐foliaged cv. Rubine was much less attacked by Pieris rapae than any of the twenty‐five green‐foliaged cultivars tested, the least attacked of which were The Aristocrat, Continuity, Evergreen and Pride of the Market. Rubine also showed some resistance to attack by Mamestra brassicae and Evergestis forficialis, as did The Aristocrat. Continuity, though as resistant as any of the cultivars to E. forficialis, was not resistant to M. brassicae. No evidence of antibiosis was found and resistance, based on non‐preference, is considered to result from ovipositing P. rapae adults discriminating against the red colour of Rubine and against the leaf composition (relative volatile content) of the green‐foliaged resistants. This could also apply with M. brassicae and E. forficialis.