bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic improvements in winter wheat yields since 1900 and associated physiological changes
Authors: Austin R. B. , Bingham J. , Blackwell R. D. , Evans L. T. , Ford M. A. , Morgan C. L. , Taylor M. 
Published: March 2009

SummaryExperiments were carried out to assess the increase in yield potential of winter wheat in the U.K. due to variety improvement since the early years of this century. The effects of other genetic changes were minimized by applying fungicide to control eyespot and foliar diseases, and by using nets to prevent lodging. The experiments were carried out in 1978 at Cambridge. One, on soil of high fertility in Camp Field, received 104 kg N/ha and the other, on soil of lower fertility in Paternoster Field, received 38 kg N/ha. Twelve genotypes were tested. Eight were varieties which formed a chronological series beginning with Little Joss, introduced in 1908. The remaining genotypes were recently developed selections from the Plant Breeding Institute and a line bred by the French breeders, Benoist.The average yield of the 12 varieties and lines tested was 3·96 t/ha in Paternoster Field and 6·40 t/ha in Camp Field. In both fields the two highest yielding entries, Hobbit and the advanced breeding line 989/10, outyielded Little Joss by close to 40%. Benoist 10483 was the only entry for which the percentage yield advantage depended on high soil fertility.The newer, high yielding, varieties were shorter and reached anthesis earlier than the older varieties. They had lower stem weights/m2than the older varieties but similar maximum leaf area indices and leaf weights/m2. Within each experiment the total dry-matter production of the varieties was similar, the increase in grain yield due to variety improvement being associated mainly with greater harvest index (ratio of grain yield to grain + straw yield).It is argued that by a continuation of the trend towards reduced stem length, with no change in above-ground biomass, breeders may be able to increase harvest index, from the present value of about 50% to about 60%, achieving a genetic gain in yield of some 25%. As the limit to harvest index is approached, genetic gain in yield will depend on detecting and exploiting genetic variation in biomass production.
Intake and metabolism studies with fresh and wilted silages
Authors: Morgan C. A. , Edwards R. A. , McDonald P. 
Published: March 2009

SummaryFresh and wilted silages (dry matter 169 and 359 g/kg; pH 4·00 and 5·09; lactic acid 165 and 34 g/kg D.M., respectively) were made from ryegrass and used in intake and metabolism experiments with cattle and sheep. Complete ruminant diet (CRD) was used as a control.Voluntary dry-matter intake of the silages by wether sheep was not significantly different (70·7 and 69·1 g/kg W0·75 for fresh and wilted material, respectively) but was significantly higher (P < 0·001) for CRD (97·9 g/kg W0·76). With rumen-fistulated steers the voluntary intakes of dry matter for the fresh and wilted silages and CRD were 117·1, 105·7 and 130·4 g/kg W0·76, respectively, and were not significantly different. The digestibility of dry matter was significantly higher (P < 0·01) for the fresh and wilted silages (0·751 and 0·698, respectively) than for the CRD (0·608). When incubated in nylon bags in the rumen the silages rapidly lost nitrogen and only 0·2 and 0·3 of nitrogen of the fresh and wilted materials, respectively, remained after 1 h. Between 0·4 and 0·5 of the residual nitrogen in the silages was subsequently lost over a period of 24 h. The loss of the nitrogen of the CRD was much slower and 0·3 of the nitrogen remained after 24 h. The rate of loss of digestible cell wall constituents was similar for the fresh and wilted silages but was slower for the CRD. The silages gave similar rumen fermentation patterns (pH, total volatile fatty acids, acetic, propionic, butyric, valeric and hexanoic acids and ammonia concentrations) during the period following their consumption.The palatability of the fresh and wilted silages, measured with rumen-fistulated sheep, was less than that of the CRD and a ruminal effect on intake was observed in the case of the silages.The high intake of the fresh silage is noteworthy, as it casts grave doubt on the widely held view that fermentation acids, particularly lactate, are pre-eminent in governing the voluntary intakes of silages.From the rapid loss of nitrogen from the silages in nylon bags in the rumen it is concluded that, to increase the utilization of nitrogen, it would be advantageous to reduce protein breakdown in the silo and to supplement silage with a readily available energy source.
Colonization of lateral, seminal and adventitious roots of wheat by the take-all fungus, Gaeumannomyces graminis var. tritici
Authors: Gilligan C. A. 
Published: March 2009

SummaryProgressive colonization of adventitious, seminal and lateral roots of wheat by Gaeumannomyces graminis var. triticiwas monitored for 18 days after direct inoculation of roots. Adventitious roots supported greater colonization by superficial runner hyphae above and below inoculation sites than did seminal roots due to more rapid establishment of colonization. Subsequent rates of superficial runner hyphal growth along the two types of root were not significantly different. In contrast with seminal and lateral roots, adventitious roots did not show any dark stelar discoloration during the period of observation. Both the rate of growth of superficial runner hyphae and of advance of dark stelar discoloration were substantially slower on lateral roots than on seminal roots. After an initial period of equal growth above and below inoculation sites, superficial runner hyphae grew more slowly below than above these sites on all three types of root.
The effects of various deacetylation procedures on the nylon bag digestibility of barley straw and of grass cell walls recovered from sheep faeces
Authors: Bacon J. S. D. , Gordon A. H. 
Published: March 2009

SummaryTwo poorly digested materials, barley straw and grass cell wall residues recovered from sheep faeces, were treated with sodium ethoxide, methoxide or hydroxide under various conditions and the effects on their digestibilities studied by the nylon bag technique in the sheep rumen.Acetyl groups were removed during these treatments and the degree of deacetylation could be controlled by adjusting the amounts of reagents used, about 25 m-mole of base/g being required to produce the maximum effect. Sodium ethoxide in ethanol was the least effective of the reagents used: it did not remove acetyl groups from barley straw and left a larger proportion untouched in faeces cell walls than did sodium methoxide in methanol.Irrespective of the reagent employed digestibility increased with the progress of deacetylation and the two processes reached a maximum together, but there was not a linear relation between acetyl content and digestibility. In the case of straw treated with sodium hydroxide there appeared to be a linear relationship between digestibility and the amount of reagent applied, up to 20 m-moles/g straw.Phenolic ester groups were less susceptible to the reagents tested than acetyl groups. It is concluded that the action of the basic reagents is probably upon polysaccharides other than cellulose, that access to some regions of the cell walls may be limited by the solvent present, and that the linkages that restrict digestibility have a sensitivity to basic reagents similar to that of the acetyl ester groups present.
Boron requirement and deficiency symptoms of fenugreek (Trigonella foenum–graecum) as shown in a water culture experiment with inoculation of Rhizobium
Authors: Mølgaard P. , Hardman R. 
Published: March 2009

SummaryThis experiment was made to determine the possible reason for deficiency symptoms seen on fenugreek (Trigonella foenum-graecum) in field trials during the dry summer of 1976. Using rockwool cubes for root support, it was shown that symptoms seen in the field plants resulted from boron deficiency.The symptoms of boron deficiency in fenugreek are described and illustrated. The main symptoms were failure offloweringor fertilization, decreased apical growth, small crisped leaves in a terminal rosette and a gradual yellowing of the lower leaves. In combination with low nitrogen, the boron-deficient plants had yellow, succulent leaves at a very early stage. High calcium and high nitrogen increased the demand for boron.Inoculation with Rhizobium meliloti of plants with a low nitrogen supply was performed with success. The bacteria formed healthy, pink nodules on the roots inside the rockwool cubes.The lowest content of boron in whole plants showing boron deficiency symptoms (no pods formed) was 13 μg/g and in this respect fenugreek is very similar to lucerne (Medicago sativa), a plant known to have a high boron requirement. Fenugreek has a high tolerance of excess boron.
The significance of damage during imbibition to the field emergence of pea (Pisum sativum L.) seeds
Authors: Powell Alison A. , Matthews S. 
Published: March 2009

SummaryDifferences in the field emergence of seed lots of vining peas were shown to be largely due to differences in the sensitivity of seeds to imbibition damage caused by the rapid uptake of water. The reduced emergence seen for all lots in wet soil resulted from a faster rate of water uptake and a consequent increase in imbibition damage. This caused both physiological death of low vigour seed lots and enhanced predisposition to pre-emergence mortality in unsterilized soil in all lots. The potential for the chemical protection of seeds against rapid water uptake is discussed.
The effect of temperature on cold hardening ofLoliutn perenneseedlings
Authors: Fuller M. P. , Eagles C. F. 
Published: March 2009

SummaryThe variation in hardening responses under different temperature regimes for three cultivars ofLolium perenneL. is described. The relative cold hardiness of the cultivars was modified by different temperatures during hardening. A threshold temperature existed above which hardening did not occur, but this temperature varied between cultivars.Although continuous low temperatures (2 °C) favoured hardening, hardening also occurred under warm day and cool night conditions (15:2 °C) where cultivars showed contrasting hardiness responses in daylengths of 16, 12 and 8 h. Under some of these conditions both leaf growth and hardiness were possible.The significance of these results is discussed in terms of the development of screening techniques and breeding objectives.
Some effects of bran and cellulose on the water relationships in the digesta and faeces of pigs Part I. The effects of including bran and two forms of cellulose in otherwise normal rations
Authors: Cooper P. H. , Tyler C. 
Published: March 2009

1. Attempts to investigate the physical properties of bran, and other feedingstuffs, with regard to their ability to absorb and retain water, have been outlined.2. Two experiments have been described in which pigs were fed bran, fibrous cellulose, or different levels of powdered cellulose, added to normal pig rations. These experiments involved 24 hr. faecal collections, and ultimate slaughter of the animals, together with analysis of faecal material and gut contents.3. The addition of bran or fibrous cellulose to a ration causes a reduction in the average percentage of dry matter in the faeces, but tends to emphasize fluctuations in faecal dry-matter percentage, which are attributed to fluctuations in rate of passage through the large intestine.4. The behaviour of the powdered cellulose was anomalous, giving rise to hard stools. It appeared to be almost inert in relation to water.
Studies on the Northern Rhodesia Hyparrhenia veld Part I. The grazing behaviour of indigenous cattle grazed at light and heavy stocking rates
Authors: Smith C. A. 
Published: March 2009

1. The normal pattern of grazing behaviour of free-range indigenous cattle under conditions of lenient stocking and overstocking has been studied throughout the year.2. There was a fairly fixed daily pattern of herd behaviour. The cattle usually started day grazing round sunrise and ceased approximately 1 hr. after sunset. There was a morning and afternoon peak of intense grazing activity separated by a rest period and watering about midday. There was usually one peak of night grazing.3. The average daily grazing times varied from 8 hr. during the rains period of relative feed abundance, to about 13 hr. during the dry season period of malnutrition.4. During the dry season there were no major differences in grazing times between the leniently stooked and overstocked groups. Both herds were losing weight.5. The relatively greater weight gains of the overstocked herd compared with the leniently stooked group during the rains resulted from the increased grazing times of the overstocked herd.6. The night grazing remained fairly constant at approximately 20% of the total daily grazing time.7. There were no seasonal effects on the pattern of grazing behaviour. High daytime temperatures did not cause an increase in the proportion of night grazing of indigenous cattle.
The effects of annual precipitation and its distribution on grain yield of dryland cereals
Authors: Hadjichristodoulou A 
Published: March 2009

SUMMARYData collected from 1968 to 1981 were used to study the effects of annual precipitation and its distribution on grain yield of three barley and six wheat varieties from 19–47 environments.The percentage of the variation in grain yield explained by annual precipitation varied with variety and species (5–31% in barley and 31–79% in wheat). The distribution of precipitation was the major factor affecting grain yield, although it varied with variety, and explained 72–92% of the variation in barley and from 75 to 98% in wheat.Only 33 of the 144 simple correlation coefficients between grain yield and precipitation during each of the 16 fortnightly periods were significant. The expected average effect on yield due to additional precipitation above the mean showed positive effects in barley during the presowing and heading to flowering periods; no consistent trend was found in the wheat.Improved agronomic practices could alleviate the adverse effects of the low and unevenly distributed precipitation by reducing losses and increasing storage of water in the soil. Breeding could contribute greatly towards high and stable yields in drylands.
The effect of implantation of anabolic steroids into suckling and ruminating lambs on the metabolism of alanine in livers perfused in the presence or absence of volatile fatty acids
Authors: Richardson T. C. , Jeacock Marjorie K. , Shepherd D. A. L. 
Published: March 2009

SUMMARYThe effect of implantation of trenbolone acetate and oestradiol into lambs soon after birth on the metabolism of alanine in the presence and absence of propionate has been studied in isolated perfused livers obtained from suckling and from ruminating lambs. The effect of butyrate on the metabolism of alanine in the presence and absence of propionate has been studied in livers obtained from the steroid implanted lambs.Glucose production in the presence of alanine by livers from non-implanted suckling lambs was more than 3 times greater than that by livers from non-implanted ruminating lambs. Steroid implantation did not affect alanine uptake by the livers but metabolism within the livers was altered. Significant interactions were observed between the age of the lambs and whether or not they had been implanted with steroids for the rates of net glucose production in the absence of propionate (P< 0·01) and for the rates of release of urea by the livers in the presence of (P< 0·05) and absence of propionate (P< 0–01).Propionate did not affect alanine uptake by livers obtained from either suckling or ruminating lambs, but there was a significant interaction (P< 0·05) between the age of the lambs and whether or not butyrate was infused, indicating that butyrate depressed alanine uptake by livers obtained from implanted ruminating lambs perfused in the absence of propionate. Despite this depression of alanine uptake the rates of net glucose production and urea production were unchanged, indicating that butyrate modified the metabolism of alanine in the livers of implanted ruminating lambs in that a greater proportion of the alanine carbon taken up must have been converted to glucose. Butyrate stimulated net glucose production in the presence of propionate and alanine in livers from suckling (P< 0·05) but not ruminating lambs. Butyrate was ketogenic and the release of 3-hydroxybutyrate accounted for 45 and 30% of the carbon taken up as butyrate by livers from suckling and ruminating lambs respectively perfused in the absence of propionate. Propionate was antiketogenic. Propionate inhibited urea formation from alanine by livers from implanted suckling (P< 0·05) and implanted ruminating (P< 0·001) lambs. This effect was diminished by the presence of butyrate. Lactate was released in the presence of propionate and accounted for approximately 12–5% of the carbon taken up as propionate.It may be concluded that implantation of lambs with anabolic steroids maintains hepatic gluconeogenesis from alanine at rates more closely resembling those found in younger suckling lambs. The effects of the volatile fatty acids on alanine metabolism are likely to be of physiological significance when sheep are fed diets which result in a markedly altered pattern of rumen fermentation.
Leaf appearance and extension in field-grown winter wheat plants: the importance of soil temperature during vegetative growth
Authors: Hay R. K. M. , Wilson G. Tunnicliffe 
Published: March 2009

SUMMARYMainstem leaf appearance and leaf extension were monitored at 7-day intervals throughout the vegetative development of field-grown winter wheat plants, during two growing seasons 1977–9. Using hourly air and soil temperature records, it was found that the rate of leaf appearance was controlled by soil temperature, with the best linear relationships being obtained using accumulated soil temperature above a base temperature of 0 °C at 1 and 5 cm depth. Leaf appearance could be predicted equally well using 09.00 G.M.T. screen air temperatures although deviations from each linear relationship were found during very cold periods when slow leaf extension rates delayed leaf appearance.Leaf extension was also found to be linearly related to temperature, with the best fit being obtained using accumulated soil temperature above 2·5 °C at 5 cm depth, suggesting a threshold of 2·5 °C for leaf extension. The response to temperature (extension per unit of accumulated temperature) was the same for all the leaves of a given plant, or sowing date; however, the fact that the rate of leaf extension increased progressively with sowing date suggests that plant response to temperature may be determined at crop emergence (possibly mediated by rate of change of day length). Leaf extension rates could be predicted satisfactorily using 09.00 G.M.T. soil temperatures (5 or 10 cm) but less so using screen air temperatures.The prediction of plant leaf areas or crop leaf area indices using such relationships between temperature and leaf growth was found to be hampered by rapid and irregular rates of leaf senescence.
Leaf and curd production in cauliflower varieties cold-treated before transplanting
Authors: Wurr D. C. E. , Fellows Jane R. , Crisp P. 
Published: March 2009

SUMMARYTwo experiments at Wellesbourne studied the effects of cold treatments on the leaf and curd production characteristics of a range of annual and biennial varieties of cauliflowers.Cold treatments delayed curd initiation and had a variable effect on the final number of leaves, but reduced the spread of curd initiation of plants which were 5 weeks old when cold-treated. The overall rate of leaf production and the final number of leaves generally increased with later-maturing varieties while initial rates of curd expansion generally declined.The annual varieties produced a small number of leaves and fairly synchronously formed a curd which developed rapidly; the biennial varieties had a higher rate of leaf production after transplanting and then changed to the generative state over a more prolonged period, following which the curd developed slowly.
The effects of very deep ploughing and of subsoiling on crop yields
Authors: Russell E. W. 
Published: March 2009

1. Deep tillage, namely, ploughing to a depth exceeding 12 in., or subsoiling to a depth of about 18 in., increased crop yields on about half the fields in which an experiment was made. Unfortunately, it was not possible to recognize what was the difference in soil properties between the 50% of fields that responded appreciably to deep tillage and the remainder whose yields were either unaffected or sometimes reduced by deep tillage, though, as one would expect, sands were normally less responsive to deep tillage than the heavier soils.2. On the clay soils, deep ploughing in autumn tended to give a surface soil that dried out up to several weeks earlier in the spring than land that was shallow ploughed. Subsoiling did not cause the surface soil to dry out in the same way. Only rarely did the subsoil brought up by deep ploughing give difficulty in working down to a seedbed, and probably in as high a proportion of fields the subsoil worked easier than the surface soil.3. On the clays and loams, the response of potatoes to deep tillage was more marked on fields that were heavily manured than on those lightly manured.4. Sugar beet normally gave a higher yield if its potash and phosphate was spread on the land before ploughing, even if this was in the autumn, than if it was applied in the seedbed. The exceptions to this result were for soils heavier than sandy loams if ploughing depths exceeding 12 in. were used, for the yield of beet was, on the average, depressed on these soils if the potash and phosphate was ploughed in compared with it being worked into the seedbed.5. Deep ploughing tended to give better control of many perennial weeds, and often of annual weeds than shallow ploughing. It is suggested that much of this benefit could be obtained when ploughing to 9–10 in. deep if ploughs were used that cut a furrow considerably wider than the conventional 10½–11 in. furrow, so allowing more complete inversion of the furrow slice.