bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comparison between ytterbium acetate, ruthenium phenanthroline and indigestible acid detergent fibre in a double-marker system for intestinal flow measurements in steers
Authors: Ortigues I. , Oldham J. D. , Smith T. , Courtenay M. B. de , Siviter J. W. 
Published: March 2009

SUMMARYThree double-marker systems were used in cannulated steers offered straw-based diets supplemented with barley, fishmeal or a combination of both, in an attempt to reduce the risks of misinterpreting biological results based on calculations of digesta flows using markers. Ruthenium phenanthroline (Ru-phe), ytterbium acetate (Yb-ac) and the indigestible acid detergent fibre fraction (IADF) were used as markers of the particulate phase of digesta in conjunction with Cr-EDTA as a liquid-phase marker to estimate duodenal and ileal digesta flows. The present paper presents the difficulties met in the application of marker techniques.The particulate marker used in a double-marker system for calculation of nutrient flow modified the degree of statistical significance observed for dietary treatment effects on digesta flow parameters.The data suggest that the type of diet used affects the behaviour of individual markers in different ways and could incur some bias in the results. It is hypothesized that the physical and chemical characteristics of digesta, in different dietary conditions, can be responsible for differential attachment of markers to particles of the solid phase. In such cases, the distinction made in the double-marker technique between particulate and liquid phases may not be sufficient to correct for lack of representativeness of digesta contents sampled from T-shaped cannulae.For the diets studied it was concluded that the interpretation of digestion parameters should be based on both Ru-phe and Yb-ac results.
An approach for breeding varieties of rice resistant to bacterial leaf blight with induced mutations
Authors: Nakai H. , Goto M. 
Published: March 2009

SUMMARYThe studies were designed for breeding resistant varieties of rice to bacterial leaf blightcaused by Xanlhomonas oryzae (Uyeda et Ishiyama) Dowson with induced mutations. In 1971, seedlings of irradiated lines (X$) originated from treatments of 60Co γ-and X-radiation and control (C6), which were propagated in bulk up to X6(C6) generations after the treatments, were inoculated with highly virulent isolates.The results showed that the variability of disease reaction within the irradiated lines increased in both resistant and susceptible directions from the control mean. It was assumed from these results that the irradiation treatments could induce polygenic mutations to give both germ types more resistant and those more susceptible to bacterial leaf blight, suggesting that such treatments might be an effective approach for breeding varieties resistant to the disease.
Influence of seeding time on the yield of white clover/orchardgrass mixtures in Atlantic Canada
Authors: Fraser J. , Kunelius H. T. 
Published: March 2009

SUMMARYThe influence of four seeding times on herbage dry matter (DM) yields and clover content of white clover (Trifolium repens L.)/orchardgrass (Dactylis glomerata L.) mixtures was evaluated at Truro, Nova Scotia and Charlottetown, Prince Edward Island from 1985 to 1988. Sacramento, Sonja and Milkanova white clover/orchardgrass mixtures were assessed under simulated grazing (four or five harvests per year) over two production years at each location.Delaying seeding from May to August reduced total herbage DM yields significantly in the first production year, from 8·1 to 3·3 t/ha in Truro and from 11·0 to 7·2 t/ha in Charlottetown. Late seeding significantly reduced clover content in the herbage of the first two harvests in the first production year but, by the mid to late-season harvests, white clover content had increased to levels similar to those of the May seeding. Estimated white clover DM yields were highest in June, and dropped in the second production year at both locations. Sonja and Milkanova white clovers consistently outyielded Sacramento in herbage DM yields and clover content in both locations irrespective of seeding dates.
Physical structure of twelve forage species in relation to rate of intake by sheep
Authors: Wilman D. , Mtengeti E. J. , Moseley G. 
Published: March 2009

SUMMARYIn order to understand better the relationship between plant physical structure and rate of intake, twelve plant species were compared: Trifolium repens L., Medicago sativa L., Onobrychis viciifolia Scop., Desmodium intortum (Mill.) Urb., Brassica napus L., Spergula arvensis L., Lolium perenne L., Lolium multifiorum Lam., Festuca arundinacea Schreb., Chloris gayana Kunth, Cenchrus ciliaris L. and Zea mays L. The effects of early as opposed to late harvesting were compared. Plants were grown in a heated glasshouse in each of 2 years, examined for morphology, anatomy, neutral detergent fibre and digestibility, and fed to sheep for 1-min test periods to record rate of intake.Rate of intake was in the order tropical grasses < temperate grasses < broad-leaved species < S. arvensis. The range was wide: from 4·6 g dry matter/min with C. gayana to 15·6 g with S. arvensis. The lowest rate of intake was associated with the possession of a large number of veins, close together, in parallel lines (tropical grasses); a rather higher rate was associated with fewer veins, further apart, in parallel lines (temperate grasses); the next to the highest rate was associated with broad leaves, which had a network of veins; the highest rate was associated with thin stems containing thin vascular bundles. L. perenne, L. multifiorum, C. gayana and C. ciliaris were similar in the thickness of large and small leaf blade veins and leaf sheath veins. F. arundinacea and Z. mays had rather thicker veins. T. repens, 0. viciifolia. D. intortum and B. napus were similar in the thickness of petiole vascular bundles. Neutral detergent fibre was lowest in B. napus and highest in C. gayana and C. ciliaris. In vitro digestibility was highest in B. napus and lowest in D. intortum.
Rate of change in harvest index during grain-filling of wheat
Authors: Moot D. J. , Jamieson P. D. , Henderson A. L. , Ford M. A. , Porter J. R. 
Published: March 2009

SUMMARYA constant rate of change in harvest index (dHI/dt = k) has recently been incorporated into several crop simulation models, so that final grain yield can be calculated from final biomass and the duration of grain growth. Implicit is the assumption that dHI/dt is conservative across treatments and environments. This assumption was tested using data from five experiments grown in the United Kingdom (1973, 1978, 1994) and New Zealand (1992, 1993). The experiments included commercial spring and winter wheat cultivars introduced during the last 100 years and nitrogen, irrigation, sowing date, temperature and CO2 treatments. In all cases, the time course of harvest index (HI) had an initial lag phase, a linear phase and a maturation phase. The linear phase was stable in field-grown crops, except for a reduction in slope after lodging in some crops. Values for dHI/dt, taken as the slope of the linear phase, varied with variety and available nitrogen, were stable for a given variety among years, and were unaffected by water stress. Variation in dHI/dt among varieties was independent of their year of introduction, although those with the Rht2 semi-dwarfing gene generally achieved a higher final HI due to a reduced lag phase. Differences in the duration of the linear phase also caused differences in the final HI after drought. The upper and lower limits of dHI/dt for fieldgrown crops were 1·37 and 0·64% d-1 but, under normal fertility conditions, the variation was between 0·90 and 1·19 % d-1. Results indicated that dHI/dt could provide an effective semi-empirical relationship for predicting grain yield in simulation models. The consistent, linear nature of this relationship suggests a physiological maximum for dHI/dt, for a given species and variety. It may be possible to exploit varietal differences in dHI/dt, and in the lag phase, for yield improvement.
Effect of the inclusion of tropical tree legumes, Gliricidia sepium and Leucaena leucocephala, on the nutritive value of silages prepared from tropical grasses
Authors: Tjandraatmadja M. , MacRae I. C. , Norton B. W. 
Published: March 2009

SUMMARYSilages were prepared from the tropical grasses, pangola grass (Digitaria decumbens) and setaria (Setaria sphacelata), with the addition of molasses (4% w/w) and/or leaves (33%) from the leguminous trees leucaena (Leucaena leucocephala) and gliricidia (Gliricidia sepium). All forages were grown at the University of Queensland farm in south eastern Queensland during 1985. These silages, together with hays made from these grasses and sorghum silage (13 diets) were fed to sheep to assess their nutritive value. All silages were well preserved, as indicated by low pH (3·5–4·4), low ammonia N (26–57 g/kg total N) and high lactic acid (73–95% total acids) contents. The addition of legumes increased both the dry matter (DM) and total N (TN) contents of silages to the same extent as the addition of both legumes and molasses at ensiling. Sheep given silages prepared from pangola grass and legumes (±molasses) consumed similar DM intakes (22·9–25·4 g/kg0·75 per day) as sheep given pangola grass hay (23·9 g/kg0'75 per day). Silage made from pangola grass + molasses was of low palatability (16·1 g/kg0·75 per day). The digestibilities of silage DM (DMD) and its fibrous components were significantly (P<0·05) lower (DMD 53·3–60·6%) than that of pangola hay (DMD 64·7%). Silages and hay made from setaria, and sorghum silage, were of lower nutritive value than those from pangola grass. The addition of leucaena and molasses increased silage DM intakes (21·1 g/kg0·75 per day) above those for setaria hay and setaria + molasses silage (16·7 and 19·0 g/kg0·75 per day respectively). The intakes of silages made from gliricidia (17·1 g/kg0·75 per day) were significantly (P <0·05) improved when molasses was included at ensiling (21·8 g/kg0·75 per day). The digestibilities of silage DM were significantly (P<0·05) higher (DMD 53·6–60·4%) than that of setaria hay (DMD 40·6). Liveweight change in sheep was significantly (P<0·05) correlated with intakes of digestible DM (r2= 0·74) and with N intake (r2= 0·82). The inclusion of legumes in the silages increased N retention and, for setaria silages, also increased rumen ammonia concentration. It was concluded that tropical grasses can be effectively ensiled by the addition of legumes alone and, with the exception of setaria/gliricidia silages, the resultant silages were of sufficiently high quality to merit their use in tropical animal production systems.
Effect of foliar application of chelated copper and manganese on yield components and fibre properties of Egyptian cotton (Gossypium barbadense)
Authors: Sawan Z. M. , Mahmoud M. H. , Gregg B. R. 
Published: March 2009

SUMMARYA decline in supplies of organic manures and the increased use of chemical fertilizers has led to a decrease in the micronutrient content of the soil, with attendant effects on yield.Field studies were conducted in 1986 and 1987 at the Giza Agricultural Research Centre, Egypt, to determine the effect of Cu-EDTA and Mn-EDTA foliar sprays on growth, mineral content, yield components and fibre properties of the Egyptian cotton cultivar Giza 75 (Gossypium barbadense L.).All combinations used significantly increased the uptake of Cu and Mn and the dry matter yield. The earliness of harvest and the value of yield components were all increased by the application of Cu or Mn; 25 mg/1 of both Cu and Mn gave the highest values. Lint percentage and fibre properties were not significantly affected.This study indicated that the yield of cotton, grown under otherwise standard conditions, may be increased by foliar sprays of Cu-EDTA and Mn-EDTA combined.
Physiological assessment of apetalous flowers and erectophile pods in oilseed rape (Brassica napus)
Authors: Fray M. J. , Evans E. J. , Lydiate D. J. , Arthur A. E. 
Published: March 2009

SUMMARYThe transmission of solar radiation within the crop canopies of oilseed rape is decreased both by the plant's yellow petals during flowering, and by the horizontal posture of the pods once they are formed. The significance of each of these morphologies was assessed, in the 1991/92 and 1992/93 growing seasons, by comparing the performances of an apetalous breeding line (N-o-112) and one with erectophile pods (N-5-130) with two conventional commercial genotypes (Falcon and Tapidor).The apetalous floral layer of line N-o-112 reflected and absorbed significantly less radiation than those of the conventional, petalled genotypes. This resulted in a greater transmission of photosynthetically active radiation (PAR) to the leaf and bract canopy situated below. At peak flowering, 70% more PAR was transmitted through the apetalous floral layer.The erectophile pods of line N-5-130 were angled 20–25° further from the horizontal than the conventional genotypes. The extinction coefficient (K) of its pod layer during late pod growth ranged from 0·35 to 0·44 as compared to 0·45 to 0·55 in the commercial varieties. Line N-5-130 carried a greater proportion of its total fertile pod number in the lower regions of the pod canopy compared to the two conventional genotypes. It also had a greater overall mean number of seeds per pod, and the number decreased proportionately less with depth in the canopy. The line was thus better able to maintain a higher photosynthetic area and to sustain pod and seed growth at the lower levels of the crop canopy than the conventional, commercial varieties. The potential physiological effects of apetalous flowers and erectophile pods are considered to be sufficiently beneficial for their introgression into near-isogenic lines to be pursued.
A note on differences in coat structure between the black and white areas of piebald lambs
Authors: Ryder M. L. , Adalsteinsson S. 
Published: March 2009

SummaryData are reported on a phenomenon in which piebald lambs having a coat of intermediate hairiness have black wool which is not only longer and coarser than the white wool on the same animal, but which has a different coat structure in terms of the fibre type array. Possible explanations for this effect which is apparently caused by the gene that restricts the production of pigment to certain areas of the skin are discussed. Hairy lambs and woolly lambs did not have this coat difference between the two colours.
The effect Of insect pollination on plant development and seed production in winter oil-seed rape (Brassica napus L.)
Authors: Williams Ingrid H. , Martin A. P. , White R. P. 
Published: March 2009

SummaryThe effect of insect pollination on plant development and seed yield of winter oil-seed rape, cultivar Jet Neuf, was investigated by comparing plots caged with a honeybee colony, plots caged to exclude insects and plots uncaged and 'open-pollinated' by naturally occurring insects. Plants in the bee-pollinated plots finished flowering earlier, showed more advanced pod growth, and were shorter than those in the plots without bees. Pods from the plots with honeybees contained more seed post-flowering than those from plots without honeybees but the proportion of them that grew into mature seeds for harvest was determined by water availability during seed growth.
Changes in the total tuber glycoalkaloid content of potato cultivars on exposure to light
Authors: De M. J. , Bain Maine H. , Joyce Jacqueline A. L. 
Published: March 2009

SummaryThe total glycoalkaloid (TGA) content of tubers of ten potato cultivars exposed to the light for 42 h significantly increased (P < 0·001). on average, above that of tubers kept in the dark. There were significant differences in the percentage changes in TGA content (P < 0·05) and in the intensity of tuber greening after exposure (P < 0·05) between cultivars although there was no correlation between the two characters.
Comparison of early, normal and late sowing at three rates of nitrogen on the yield, grain nitrogen and screenings content of Blenheim spring malting barley in Ireland
Authors: Conry M. J. 
Published: March 2009

SUMMARYNine experiments were carried out on three different soil types in the south-east of Ireland over three years (1989, 1992 and 1993) to test the effect of early, normal and late sowing at three rates of fertilizer nitrogen (100, 125, 150 kg/ha) on the yield and grain quality ex-farm of spring malting barley (cv. Blenheim). Early sowing (January or February) was not possible in 1990 and 1991 due to wet weather. Sowing date had a pronounced effect on grain yield and grain N content in all three years. In 1989 and 1992, the earliest-sown barley (January or February) gave significantly greater yields than latersown crops (March and April) in five of the six experiments. The earliest-sown barley gave the lowest grain N in all six experiments and there was a gradual and significant increase in grain N content as sowing date was delayed. In 1993 the earliest-sown barley (February) gave significantly lower yield and greater grain N than the March-sown crop in all three experiments. The lower yield of the February-sown barley in 1993 was due to the significantly reduced number of grains/ear. The Aprilsown barley gave significantly lower yield and greater grain N than the earlier-sown crops in eight out of the nine experiments. In 1989 and 1992 only one of the six experiments, Ferns 1992, gave a significant yield response to increased rate of N (125 kg/ha). But in 1993, 125 kg N/ha significantly increased grain yield in all three experiments and 150 kg N/ha gave a further significant increase in yield in two of the experiments. Increasing increments of fertilizer N significantly increased grain N in all nine experiments.
Seasonal changes in intake and digestion of chopped timothy hay (Phleum pratense) by three breeds of sheep
Authors: Iason G. R. , Sim D. A. , Foreman E. 
Published: March 2009

SUMMARYThe voluntary food intake (VFI) and apparent digestibility of chopped timothy hay by six Scottish Blackface (BF), Shetland (SH) and Dorset Horn (DH) non-breeding ewes were assessed in summer and winter. In two experiments VFI was higher in summer than in winter but did not differ between the breeds. In Expt 1, the seasonal difference in VFI was greater in BF and SH than in DH ewes and the apparent digestibility of dry matter (DM), organic matter (OM) and total nitrogen was consistently higher in all three breeds in summer than in winter. The higher digestibility of DM of the hay in summer than in winter was confirmed in Expt 2, in which the whole tract mean retention time (MRT) of the undigested residues was measured using 103ruthenium-phenanthroline as a marker. The MRT was lower in all three breeds in summer than in winter. In a third experiment, following at least 6 months ad libitum feeding on the hay, for all three breeds the contents of DM and liquid in the reticulorumen were smaller in summer, and the liquid fraction formed a greater proportion in summer than in winter. The results contrast with the expectation that intake and digestibility within a given forage type are negatively correlated. Although an increase in digestibility may facilitate a higher VFI in summer (BF and SH) it does not necessarily do so (DH).
An evaluation of F1 hybrid winter wheat genotypes produced using a chemical hybridizing agent
Authors: Morgan C. L. , Austin R. B. , Ford Margaret A. , Bingham J. , Angus W. J. , Chowdhury S. 
Published: March 2009

SummaryIn experiments harvested in 1985 and 1986 the grain yields of 61 F1 hybrids among winter wheat varieties and advanced breeding lines were 5·9% greater than the yields of the best parents. In a trial with 430 hybrids in 1986, the hybrids yielded 3·6% more grain than the best parents. Among these 430 hybrids heterosis for yield was greatest for those from the lowest yielding parents. This result is taken to indicate that among these genotypes most genes for high yield have been fixed in the highest yielding parents.The hybrids had slightly fewer ears/m2, but more grains per ear and heavier grains than the highest yielding parents. They yielded more straw as well as more grain.The results are compared with those from other studies and it is concluded that yield advantage of F1 hybrids so far tested is not generally sufficient to justify their introduction into U.K. agriculture.
Effect of date of application and form of nitrogen on herbage production in spring
Authors: Stevens R. J. , Gracey H. I. , Kilpatrick D. J. , Camlin M. S. , O'Neill D. G. , McLaughlan W. 
Published: March 2009

SummaryField plot experiments were carried out for 3 years at four sites to study the effect of date of application of ammonium nitrate/calcium carbonate (CAN) and urea (U) on perennial ryegrass production in spring. Fertilizer (70 kg N/ha) was applied at weekly intervals for 10 weeks from 1 February. Herbage was cut on the same day at all sites, 3–4 weeks after the last N application. CAN and U at 50 kg N/ha were immediately re-applied and a second cut of herbage was taken after 4–5 weeks. From meteorological data, the dates after 1 February when soil temperature at 100 mm depth increased to 5·5 °C and the dates when cumulative average daily air temperatures < 0 °C from 1 January reached 200 °C were calculated for each site and year.The date of application for maximum dry matter (D.M.) yield at the first cut differed with site and year, but for 11 of the 12 site/years was in February. The number of dates of application resulting in optimum yield (i.e. at least 90% of the average maximum yield response to CAN or U) varied also with site and year from one to six. Soil and air temperature predictive systems implied a precision in choice of application date that was unjustified and were no more successful at predicting the optimum application date than a simple date range. The first fertilizer application had a pronounced positive residual effect on D.M. yields at the second cut. Less precision on date of the first application was required to obtain optimum cumulative yields over both cuts than optimum yield at the first cut only.Differences in performance between CAN and U were only significant for three of the 120 fertilizer applications at the first cut. On these occasions, all in one year at two sites, U gave higher yields than CAN. Correlations were sought between D.M. yield response and growth period, air temperature, long-term rainfall and short-term rainfall for CAN and U separately. Factors relating to rainfall had no significant effect on response to U but response to CAN showed a significant negative correlation with short-term rainfall. The short-term weather forecast may therefore be another criterion to be considered in deciding when to apply N in early spring.
Use of climatic data for estimating nitrogen fertilizer requirements of dryland wheat
Authors: Korentajer L. , Berlinger P. R. , Dijkhus F. J. , Van Zyl J. 
Published: March 2009

SUMMARYThe effect of moisture stress on N fertilizer needs of spring wheat (Triticum aestivum L.) was assessed using yield and meteorological data from N x P and N x P x K factorial trials, conducted on farmers' fields in a summer and a winter rainfall area in South Africa in 1979–84. Three to five rates of N fertilizer between 15 and 135 kg N/ha (plus control) and two to four replicates were used. The data were statistically analysed by a multiple regression yield model using applied N rate, N, and seasonal moisture stress, S, as the explanatory variables. A good positive correlation (r = 0.83, S.E. = 0.341 t/ha, D.F. = 48) was obtained between the estimated and the observed yields. The effects of S on Nmax and Novl (i.e. the N rates corresponding to maximum yield and an economically optimal rate, respectively), were evaluated. For 0.05 < S 7lt; 0.3, the range of S values representative of dryland cropping conditions, Nmax was largely independent of S, whereas Nopl increased sharply with decreasing S. The results indicated that N-response models which include moisture stress parameters may be used to determine the cropping areas climatically most suitable for wheat cultivation.