bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interactions between genotype and density on the yield components of Zea mays:II. Grain production
Authors: Voldeng H. D. , Blackman G. E. 
Published: March 2009

SUMMARYSix hybrids, either pure dent or flint x dent crosses, together with two open-pollinated flint varieties of early maturity, were grown at Oxford, England, and the yield of grain determined over a range of 15 densities (5.30.8 plants/m2). The relationship of yield to density was studied by fitting mathematical functions to the observed yields. Only two functions, (1) the inverse quadratic on yield per unit area, and (2) the linear regression between density and the logarithm of grain yield per plant, were satisfactory fits. The linear regression was preferred because of its ease of calculation and interpretation. Between genotypes the largest differences in grain yield per unit area were found at densities either above or below those which are employed in normal practice.The ranking of the genotypes for grain production depended upon the density. Whereas at the lowest density a very short, early-maturing flint genotype, GaspéFlint, yielded least, and a tall, full season dent hybrid, 0X324, yielded most, this position was reversed at the higher densities. Maximal levels of yields of the open-pollinated flint varieties were low, and it is apparent that the incorporation of this source of germplasm in hybrids is limited if commercially acceptable yields are to be attained. Maximal yields of 600 g/m2 were produced by three hybrids, but the optimal densities were markedly divergent. They ranged from 6.2 plants/m2 for 0X324 to 9.7 and 10.8 plants/m2 for INRA 270 and INRA 200. Possible reasons for such differences are discussed in terms of the interactions of density and genotype on the components of yield.
Effects of sulphur fertilizers and of copper on the yield and composition of spring wheat grown in an sandy soil prone to surface compaction
Authors: Bolton J. 
Published: March 2009

SUMMARYA condition known as ‘scorch” with symptoms similar to copper deficiency often occurs in dry weather on cereals grown on a sandy soil (at Woburn) with an unstable structure. Plants with symptoms contained more sulphur than normal and sulphur/ copper interactions were suspected.Sulphur fertilizers tested in two pot experiments with this soil did not induce copper deficienciesbut increased grain and straw yields of spring wheat especially at higher nitrogen rates. Yields were increased when the mature grain contained less than 0.12% S and the straw less than 0.5% Sin the dry matter. Sulphur concentrations were larger in plants grown in the greenhouse rather than in growth cabinets and in plants grown in oven-dried rather than air-dried soil.Soil-applied copper sulphate slightly increased grain yields in pots but in one experiment there were no corresponding increases in copper contents of the crop. In a field experiment where ‘scorch’ symptoms occurred in 1972, copper oxychloride sprays increased copper concentrations but not yields of the grain.These results suggest that copper deficiency is unlikely to be a primary cause of ‘scorch’ symptoms.
Relationships between the times of transplanting, curd initiation and maturity in cauliflower
Authors: Wurr D. C. E. , Fellows J. R. , Hiron R. W. P. 
Published: March 2009

SUMMARYIn order to determine the accuracy of controlling the time of maturity of a cauliflower crop by regulating the planting date, a series of transplantings of the variety White Fox was grown on a range of sites over 3 years and sampled throughout growth.The time from transplanting to maturity and the time from curd initiation to maturity were both quadratically related to the time of transplanting but there were marked differences in the relationships between years. Differences between years in the time taken to reach maturity tended to increase with later transplanting; for example, cauliflower crops transplanted in May took between 77 and 94 days to mature, while those transplanted in July matured in as few as 67 or as many as 106 days. These differences resulted from a combined effect of the time taken to satisfy the vernalization requirement and the duration of curd growth, both of which are temperature-mediated and therefore subject to seasonal and annual variation. Differences in the vernalization requirements of different cauliflower crops are illustrated by the number of leaves formed before curd initiation, which varied from 22·5 to 37·3.Variation in the time to maturity between crops transplanted at similar times of the year, in the same and different years, resulted in large deviations from planned production programmes and it is suggested that a complementary technique to aid crop marketing would be prediction of the time of crop maturity. However, the data collected in this study show that predictions based on the duration of crop growth from transplanting or curd initiation are unlikely to be sufficiently accurate and it is argued that predictions should be based on changes in curd dimensions with time.
Estimation of pituitary secretion rate during the reproductive cycle of sheep
Authors: Lindsay K. S. , Fleet I. R. , Walters D. E. , Heap R. B. 
Published: March 2009

SUMMARYA technique has been developed for the measurement of pituitary hormone secretion rates in conscious sheep. The technique involves the continuous and simultaneous sampling of blood from the carotid artery and jugular vein and the measurement of cephalic blood flow by an indicator dilution technique. Veno-arterial differences in hormone concentrations multiplied by cephalic blood flow gave average secretion rates which were measured after single or repeated large doses of luteinizing hormone releasing hormone (LHRH) and thyrotrophin-releasing hormone (TRH) at various times in the reproductive cycle.
A study of root and shoot interactions between cereals and peas in mixtures
Authors: Tofinga M. P. , Paolini R. , Snaydon R. W. 
Published: March 2009

SUMMARYWheat, barley and two morphologically contrasting cultivars of peas (leafy and semi-leafless) were grown in pure stands, at standard agricultural densities, and in additive mixtures of cereals with peas. The stands were grown in boxes in the field, and partitions were used to separate the effects of root and shoot interactions. The cereals and peas were either planted at the same time, or one species was planted 10 days before the other. The origin of the N present in each species was determined by applying N fertilizer labelled with 15N.Both cultivars of peas had greater shoot and root competitive abilities than wheat or barley, probably because of their larger seed size; leafy peas had greater shoot and root competitive abilities than semi-leafless peas. Sowing peas after cereals reduced their competitive ability.The relative yield total (RYT) of cereal-pea mixtures, based on total biomass, averaged 1·6 when only the root systems interacted, and 1·4 when only the shoot systems interacted, but did not differ significantly from 10 when both root and shoot systems interacted. RYT values were greater when peas were grown with wheat, rather than with barley, and when peas were sown at the same time as the cereals.Shoot competition from peas increased the N% of cereals, but substantially reduced their total N content, because biomass yield was reduced. Shoot competition from cereals had no effect on the N% of peas, and only slightly reduced their total N content. Shoot competition between cereals and peas had no significant effect upon the proportion of N derived from various sources by either cereals or peas.Root competition from peas significantly reduced both the N% and total N content of cereals. Root competition from cereals had little effect on the N% of peas, but significantly reduced their total N content and increased the proportion of N derived from rhizobial fixation from 76 to 94%. Since cereals and peas largely used different sources of N, resource complementarity for N was probably an important component of intercropping advantage, when the roots of cereals and peas shared soil resources.
Amino acid composition of degradation-resistant peptides in extracellular rumen fluid of sheep
Authors: Wallace R. J. , Newbold C. J. , Watt N. D. , Buchan V. , Brown D. S. 
Published: March 2009

SUMMARYRumen fluid was removed from four sheep 6 h after feeding, and the fluid was centrifuged to remove the micro-organisms. Perchloric acid (PCA) was added to the supernatant fluid to precipitate soluble proteins, which were again removed by centrifugation. The PCA extract was neutralized with KOH and the precipitate was removed by centrifugation. The supernatant fluid was hydrolysed with 6 MHC1 at 110 °C for 24 h, then dried by rotary evaporation, and the amino acid composition of each extract was analysed by ion-exchange chromatography. The recovery of amino acids was 98%, except for methionine, cysteine and tryptophan, which were destroyed. The recovery of amino acids from added Trypticase was 92% of the peptide mixture as amino acids. The free amino acid composition of extracellular rumen fluid was low and variable in both amount and composition (0·36, S.D. 0·49, μmol/ml). The concentration of amino acids released by acid hydrolysis of the PCA extract, presumed to be derived from peptides, was larger and its composition was less variable (1 ·02, S.D. 0·30, μmol/ml). Aspartic acid and histidine were enriched in peptides in comparison with the amino acids present in the feed or in rumen particulate material. Glycine and proline contents were higher in peptides that in particulate material. In contrast, the contents of isoleucine, leucine, tyrosine and phenylalanine tended to be lower in peptides than in the other materials. It was concluded that extracellular degradation-resistant peptides had a composition that was different to microbial protein and to the feed. The peptides appeared to be enriched for amino acids which previous studies with pure peptides had shown tend to make peptides more resistant to degradation.
Frequency distribution of shoot weight of plants in populations ofTrifolium repenspersisting by clonal growth in grazed pastures
Authors: Hay M. J. M. , Thomas V. J. , Brock J. L. 
Published: March 2009

SUMMARYOver two years (1984/85 and 1986/87), monthly sampling of shoots of white clover plants compared the populations of white clover in mixed swards at Palmerston North, New Zealand, under set stocking, rotational grazing and a combination of both systems, at a common stocking rate of 22·5 ewe equivalents/ha.The frequency distributions of shoot (or stolon) dry weight per plant in each population over the study period was described by a log-normal model, which indicated that the populations consisted of many small individuals and few large individuals. Such inequality of shoot dry weight within populations is commonly termed size hierarchy; a statistic giving a measure of such size hierarchy is the Gini coefficient. The populations under different managements had similar Gini coefficients which differed little among seasons or between years. Lack of significant correlation between the Gini coefficient and mean shoot dry weight per plant of each population indicated that, in these white clover populations, size hierarchy was independent of mean plant size.These results were considered in relation to the clonal growth of white clover in grazed swards and it is suggested that the variable nature of death of older basal stolons makes an important contribution to the variability in size of individual plants and hence to size hierarchy. As size hierarchy, as assessed by Gini coefficients, was relatively stable in these populations over 3½ years, it appears that clonal growth of white clover incorporates sufficient variability within the growth and death processes at the individual plant level to maintain the size hierarchy, irrespective of variations in mean plant size of populations.
Sensitivity analyses of the ARCWHEAT1 crop model: the effect of changes in radiation and temperature
Authors: Kocabas Z. , Mitchell R. A. C. , Craigon J. , Perry J. N. 
Published: March 2009

SUMMARYThe sensitivity of predicted final grain yield to changes in the mean and variance of daily temperature and daily log(radiation) was studied for the arcwheat1 crop model of winter wheat. These two climatic variables were each simulated by each of two stochastic models, the parameters of which were estimated from 12 years' data from Rothamsted Experimental Station.When arcwheat1 was run with systematic changes in daily temperature from – 2 °C to +2 °C in steps of 0·1 °C, there were abrupt changes in predicted final grain yield which coincided with predicted increases in leaf number. These effects were smoothed out when the stochastic climate models incorporating simulated daily variation were used as inputs, in multiple runs of arcwheat1.In such runs, the response of predicted yield to changes in the means of temperature and log(radiation) was studied both for individual developmental stages and over the entire growing season. Yield was insensitive to changes in temperature and radiation during the stage between sowing and emergence, and to changes in radiation before terminal spikelet formation.
Influence of ionophores and energy inhibitors on peptide metabolism by rumen bacteria
Authors: Wallace R. J. , Newbold C. J. , McKain N. 
Published: March 2009

SUMMARYIonophores and inhibitors of bacterial energy metabolism were added to mixed rumen bacteria prepared from sheep receiving grass hay plus concentrate diets, and their influence on the rate of metabolism of alanine (Ala) peptides was determined. Dicyclohexylcarbodiimide (DCCD) had no influence on the rate of breakdown of Ala2, Ala3, Ala4or Ala5, indicating that the metabolism of these peptides did not require ATP. The protonophores tetrachlorosalicylanilide (TCS) and carbonyl cyanidem-chlorophenyl-hydrazone (CCCP) inhibited peptide breakdown to a minor extent (< 15%), whereas the ionophores monensin and tetronasin had greater, but still small (12–31%), inhibitory effects. Toluene stimulated peptide breakdown, consistent with a permeability barrier having been removed. Thus, at least some peptide metabolism depends on transport into bacteria; transport appears not to be ATP-linked, and may well be coupled to the uptake of mineral cations rather than protons. Rumen fluid from sheep receiving a similar diet with added monensin (33 mg/kg) or tetronasin (10 mg/kg) hydrolysed Ala3and Ala4at rates that did not differ significantly from controls. Nevertheless, the peak concentration of free peptides in rumen fluid after feeding was more than doubled in ionophore-fed sheep, and peptides persisted for longer than in control animals.
Crop patterns recorded on aerial photographs of England and Wales: their type, extent and agricultural implications
Authors: Evens R. 
Published: March 2009

SUMMARYCrop patterns of natural origin and man-created crop marks are frequently recorded on aerialphotographs taken over England and Wales. They usually indicate subsil variation over short distances, but differences in crop growth may also be evident in relation to topsoil variability. Different kinds of crop patterns and the soils on which crop patterns and marks develop are briefly described. Soil associations in which crop patterns and marks are frequently and extensively recorded cover 25% (37664 km2) of England and Wales; in dry years, patterns and marks are extensively recorded over a further 6·5% (9884 km2). Crop patterns and marks indicate that over much of England and Wales crop growth may be impeded by properties intrinsic to the soil, which are not easily ameliorated by farmers. When siting crop experiments, care should be taken to avoid these areas of complex soil patterns.
Association of differences in seed vigour in long bean (Vigna sesquipedalis) with testa colour and imbibition damage
Authors: Abdullah W. D. , Powell A. A. , Matthews S. 
Published: March 2009

SUMMARYField emergence of 11 seed lots from six cultivars of long bean, all having laboratory germination of > 80%, ranged from 0 to 83%, indicating differences in seed vigour. Vigour differences occurred within and between cultivars, seed lots from cultivars with white or partly white testas having particularly poor emergence (0–21%) compared with those with brown or black testas (41–83% field emergence). The significant ranked correlations between field emergence and (i) solute leakage, measured by the electrical conductivity of seed soak water (r = –0·864), (ii) the percentage of cotyledons made up of completely living tissue, revealed by vital staining (r = 0·895), and (iii) the proportion of hard seeds (r = 0·916) indicated that lots with low vigour and potentially poor field emergence could be identified before sowing. Seed lots having low vigour imbibed water rapidly; the improved vital staining when seeds imbibed slowly indicated that damage occurred during imbibition and was a cause of low seed vigour. Rapid water uptake by low-vigour seed lots was partly explained by the incidence of seeds with cracked testas, but other factors could not be eliminated. The significance of differences in water uptake between cultivars differing in testa colour is discussed in relation to breeding for improved emergence.
Changes in faecal δ13C in response to changing proportions of legume (C3) and grass (C4) in the diet of sheep and cattle
Authors: Coates D. B. , Van Der Weide A. P. A. , Kerr J. D. 
Published: March 2009

SUMMARYFeeding studies were conducted in 1986 with penned sheep and cattle fed legume (C3) and grass (C4) hays mixed in different proportions. Large fluctuations in diet δ13C within or between days were associated with much smaller fluctuations in the δ13C of faeces. When the overall daily legume percentage in the diet was held constant, there was little variation in the δ13C of faeces irrespective of when during the day the legume, relative to the grass, was eaten.Cattle set stocked on Stylosanthes/grass pastures in Queensland showed only minor variations in faecal δ13C within or between days in the short term. All animals within a group showed similar trends when the diet was changing. The changes in the δ13C of faeces from day to day reflected small but real changes in diet selection.It was concluded that the δ13C of a single faecal sample reliably reflects the integrated diet over the previous 3–4 days of a free-grazing ruminant so that the frequency and pattern of faecal sampling for estimating diet composition may be determined by considerations other than reliability
Effects of sowing a companion grass (Lolium perenne), application of grass suppressant and choice of clover variety on the growth and seed production potential of white clover
Authors: Wilman D. , Fisher A. , Marshall A. H. 
Published: March 2009

SUMMARYThe growth and seed production potential of white clover (Trifolium repens L.) was studied in field plots in 2 years, with and without a companion grass (Lolium perenne L.). Three rates of grass suppressant, fluazifop-butyl (Fusilade), applied in early June, were compared on plots sown with the companion grass. Two clover varieties, Aberystwyth SI84 and Olwen, were compared.Sowing a companion grass reduced the amount of clover in the sward in both the first and second harvest years, but did not affect the vigour of individual clover growing points or the number of clover inflorescences when the crop was ready to be harvested for seed.Fluazifop-butyl, at the highest rate used (125g/ha), reduced the rates of leaf emergence and extension, and the numbers of reproductive tillers, in Lolium, without reducing the rate of leaf emergence in clover, although the weight per clover leaf was somewhat reduced. In the first harvest year, the numbers of SI84 inflorescences in June and July were increased by fluazifop-butyl, but the effect had worn off by harvest (24 August). Seed yield potential was not increased by fluazifop-butyl at the rates used.Olwen produced heavier leaves, but fewer leaves and fewer growing points/0·1 m2 than SI84. In the first harvest year, Olwen had fewer and smaller inflorescences than S184.It proved feasible to measure the weight of new leaf produced per week and the nett additions to stolon and inflorescence dry matter (DM). The estimate of nett addition to stolon DM was increased by increasing the number of visible internodes included in the calculation, up to the maximum number recorded (nine). The rate of leaf emergence was slower on young branches than on main axes.
Genetics of seed impermeability in soya bean
Authors: Verma V. D. , Ram H. H. 
Published: March 2009

SummarySix parental cultivars (Bragg, Bragg-black seed, Kalitur, Ankur, WT-125 and Glycine formosana), 15 F1's, eight F2's and eight F3's (Bragg × WT-125, Bragg × Glycine formosana, Bragg-black seed × WT 125, Bragg-black seed × Glycine formosana, Kalitur × WT-125, Kalitur × Glycine formosana, Ankur × WT-125 and Ankur × Glycine formosana) were evaluated for seed impermeability. WT-125 and Glycine formosana were identified as impermeable types (92·18, 77·46% impermeability, respectively). The other four varieties, namely Bragg (2·93% impermeable seeds), Bragg-black seed (11·7% impermeable seeds), Kalitur (no impermeable seeds) and Ankur (0·94% impermeable seeds) had soft seed or normal seed.The segregation pattern for impermeability in the F2 and F3 generations of eight crosses showed the involvement of a pair of dominant genes in Bragg × Glycine formosana, Bragg-black seed × WT-125, and Bragg-black seed × Glycine formosana, three pairs of dominant genes in Bragg × WT-125, Ankur × WT-125 and Ankur × Glycine formosana, and four pairs of dominant genes in Kalitur × WT-125 and Kalitur × Glycine formosana for seed impermeability, assuming maternal control as hard seed was a seed-coat phenomenon.Vr, Wr graphical analysis also indicated that WT-125 and Glycine formosana possessed mostly the dominant genes for seed impermeability, while the remaining four cultivars contained mostly the recessive genes. The correlation coefficient of Yr (parental mean) and Vr + Wr was negative and high (— 0·907) confirming that most of the dominant genes in the parental cultivars were acting towards high seed impermeability. Thus the overall results obtained through diallel analysis of 15 F1's were in agreement with those obtained through Mendelian analysis.
Studies on the gonadal and epididymal sperm reserves of Mujjafaranagri rams
Authors: Jindal S. K. 
Published: March 2009

SummaryTesticular and epididymal sperm reserves were determined in six sexually mature Mujjafaranagri rams. The testes and epididymides weight were 151·4±5·49 and 20·7±0·164 g respectively. The total spermatids/g were 78±21·8×106, while daily sperm production per ram was estimated to be 4·46×109 when corrected for tunica albuginea weight. The number of spermatozoa in the caput, corpus and cauda epididymides were 3·18, 2·56 and 16·29×lO9 respectively and they represented 14·4, 11·6 and 73·9% respectively of the sperm reserves on that side. The total epididymal sperm reserve per male ram was about 44·06×109 spermatozoa.
A study of field drain ochre deposits. 1. Abiotic chemical precipitation
Authors: Dewi I. Ap , Kelso W. I. , Johnson D. B. 
Published: March 2009

SummaryIt was demonstrated that abiotic chemical precipitation could account for a major proportion of iron hydroxide deposition in drainage water. In filter-sterilized (0·22 μm) drainage water samples from ochreous sites 84% of the total iron in solution was precipitated within 48 h. It was also shown that ferric hydroxide precipitates could catalyse the precipitation of ferric hydroxides in drainage water exposed to the atmosphere.