bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some effects of growing winter wheat continuously
Authors: Hanley F. , Ridgman W. J. 
Published: March 2009

SummaryAn experiment comparing the yield at various stages of continuous wheat growing on heavy land, using two varieties and two rates of application of nitrogenous fertilizer, is described and the results from 1963 to 1974 discussed.The yield of the second wheat crop was substantially less than that of the first following oats which followed beans, but there were no consistent yield differences between the second and later crops.The major disease present was eyespot, but the differences in yield between Cappelle-Desprez and Hybrid 46 were little affected as wheat growing continued.Increasing nitrogen application from 63 to 126 kg N/ha did not reduce the differences between first and later wheat crops.
Developmental consequences of two-row and six-row ear type in spring barley: 1. Genetical analysis and comparison of mature plant characters
Authors: Riggs T. J. , Kirby E. J. M. 
Published: March 2009

SummaryMature plant characters and yield components were measured on a two-row (Proctor) and a six-row (Clermont) spring barley variety, the F1of the cross between them, and the first back-cross to each parent.Whereas shoot dry weight in the F1significantly exceeded the mid-parental value, and chaff dry weight, stem length and weight per grain showed positive heterosis, grain yield did not exceed the mid-parental value and number of grains per plant showed negative heterosis.A scaling test showed that an additive-dominance model fitted the data in all cases except possibly for dry weight per grain, where the χ2test approached significance.The partial dominance of the two-row allele (V) for grains set per rachis node exhibited in the mature ears of theF1was not apparent at anthesis when all the lateral florets were found to have large, apparently normal stamens. However, the ratio of median to lateral grains set over all main shoot ears of theF1was 1:0·21 with an average of six lateral grains per ear.The results presented indicate that the factors determining total dry-matter production and grain yield are inherited in such a way that the restriction upon grain yield in theF1is due not to a deficiency of dry matter but to a limited capacity of the plant to store dry matter in the form of grain. This may indicate some developmental interdependence in the expression of yield component characters.
Variations among heads, plants, and ecotypes of wild safflower
Authors: Kheradnam M. , Bassiri A. 
Published: March 2009

SummarySeeds from individual heads of wild safflower (Carihamus oxyacanthaBieb.) plants collected from five locations were used in this study. Locations were situated on a roughly east-west transect passing through Shiraz, Iran. The western locations were cooler with higher annual rainfall than the eastern sites. Wild safflower plants of different locations produced about an average of 150 heads per plant, but only 60% of them contained seeds. Frequency distributions constructed for number of seeds per head, germination percentage, and seedling length showed trends of change in the skewness of the distribution for the latter two characteristics parallel to the environmental selective pressure, i.e. the skewness was towards the left for eastern locations but it gradually moved to the right for western ones. Striking amounts of polymorphism were also observed for these characters. A very high proportion of total variance was concerned with differences between heads of the same plant for number of seeds, germination ercentage, and seedling length. Very little variability was found among plants of the same ecotype.
Intra-varietal variability and response to single plant selection in Gossypium hirsutum L.: III. Response to selection
Authors: Thomson N. J. 
Published: March 2009

SummaryResponse to selection primarily for lint yield among spaced plant populations of four American and one African variety of Gossypium hirsutum L., established in 1965—6 at Kimberley Research Station, was studied in three experiments conducted between 1966 and 1970.In the first experiment, in which single-hill micro-plots of 3–5 plants per hill were used, the mean lint yield of progenies was larger than predicted from single plant heritabilities. In the second experiment, in which single-row plots were used, response to selection for lint yield was generally less than expected. In the third experiment, in which three-row plots were used, response to selection for lint yield was again less than expected and less than manifested in the second experiment. However, in all experiments responses to selection for lint percentage, lint quality properties, and height were close to expectations while some individual progenies substantially out-yielded their unselected parents.The progressive decline in response to selection for lint yield from the first to thethird experiment, and the discrepancies between the actual responses and the expected responses for lint yield in all experiments, were interpreted mainly on a basis of intergenotypic competitive effects differing in sympathy with plot size and plant disposition.It was concluded that the objective methods of selection practised were successful when judged on plant breeding criteria. It was also concluded that intra-varietal selection is an important technique by which genetic improvement can be achieved at regional breeding centres with limited resources.
Fertility levels of bulls kept at an artificial insemination centre
Authors: Cembrowicz H. J. 
Published: March 2009

The present method of estimating preliminary results in artificial insemination practice bears a definite relation to calving percentages, and, with few exceptions, may be generally adopted as a true measure of fertility.Single factors, such as an individual bull with a low conception rate, a new and less efficient inseminator, or variations in the results obtained at the Sub-Centres, etc., do not noticeably affect the average monthly conception rate in a large A.I. Centre. The most important influencing factors have been found to be the choice of diluent, and in some cases the elimination of the use of stored semen.No significant variation in fertility occurs with the season of the year, the age of the bull or the area of operation; but, for a bull to work satisfactorily at a centre and at the same time achieve good results, it is necessary that he should be treated as an individual and his psychology closely studied.In view of results obtained, one is able to conclude that methods of evaluation at present in use (estimating initial motility, density, percentage of abnormals and a test of viability by storage of diluted and undiluted samples) are up to a point satisfactory.A dilutor or buffer may influence the conception rate considerably, and it is felt that the diluent in use at present has its own fertility level.With the Centre's team of forty-eight bulls it is obvious that there must be some variation in fertility levels between individuals; but it is seen that, whereas bulls in natural service fall obviously into categories of ‘high fertility’ or ‘low fertility’, this division tends to disappear in A.I. with the application of the various techniques.
The amino-acids of sheep and cow urine
Authors: Bathurst N. O. 
Published: March 2009

1. Samples of sheep and cow urine have been analysed microbiologically for seventeen aminoacids.2. Over 90% of the total amino-nitrogen in hydrolysed urine was due to glycine.3. Bound glycine was present not only as hippuric acid but also in other forms as yet uninvestigated.
The effect of semen age on conception rate
Authors: Campbell R. C. 
Published: March 2009

1. The relationship of semen age to conception rate was studied at two artificial-insemination centres and a subcentre of one of these. Data relating to 50,213 first inseminations were included in the analysis.2. It is shown that external conditions can affect the rate of decrease of conception rate with semen age.3. Records giving c.r.'s for each day of semen age may reveal centre differences that cannot be detected in records giving mean c.r.'s only.4. Information may be lost if data are grouped by months rather than recorded by collections.5. The rate of decrease should not be used for comparing centres until the various factors affecting it (e.g. breed differences) are more fully understood. Further investigations should not be limited to one centre.
The effect of ground water-level upon productivity and composition of fenland grass (II)
Authors: Nicholson H. H. , Firth D. H. , Eden A. , Alderman G. , Baker C. J. L. , Heimberg M. 
Published: March 2009

1. Further studies were carried out during 1950 on the effects of different ground water-levels upon the productivity and composition of Italian ryegrass grown on a calcareous light peat soil. The season was an unusually wet one, in contrast with the dry season experienced in 1949.2. Seven successive cuts were taken during the season from each of two crops of ryegrass, one following a crop of marrow-stem kale, and the other a crop of celery. Different amounts of a general compound fertilizer had been applied.3. Generally, the findings confirmed those of the previous year's investigation. High ground waterlevel (approximately 18 in. below ground surface) had a deleterious effect upon the yield and quality of ryegrass as reflected by its protein content, compared with the medium and low water-levels (23 and 30 in. below ground surface, respectively).4. The high water-level also had a depressing effect upon the percentage of potassium and magnesium in the grass, but had no consistent effect upon calcium and phosphorus. The silica content rose steadily in all cases as the season advanced, as occurred in the previous year.5. Residual manuring effects were well marked in the crop following celery. The total yields of dry matter from the medium and low water-levels considerably exceeded those of similar plots following kale, and the protein contents were also appreciably higher. This demonstrates the advantages of a high soil nutrient status, under conditions of suitable water-levels, for a crop of fenland grass.6. A high water-level inhibited growth and quality, irrespective of the nutrient status of the soil.
The response of yam (Dioscorea rotundata) to fertilizer application in Northern Ghana
Authors: Koli Stephen E. 
Published: March 2009

SummaryField trials were carried out for three years in the savanna zone of northern Ghana to determine the fertilizer requirements of yam (Dioscorea rotundata). Under the conditions of the experiment, K was not important in yam fertilization. Release from the exchangeable reserves was adequate in meeting the crop demand. A small positive response to P applied at low levels (33·6 kg/ha) was observed and averaged only 5·6% increase in yield. N was the most important nutrient element and its application increased yields highly significantly. On the average, application of 33·6 kg/ha gave an increase of 13·5% and 67·2 kg/ha gave a 22·1% increase in yield. More N did not further increase yield.
Manuring of potatoes on fen silt soils in Holland, Lincolnshire
Authors: Berryman C. , Batey T. , Caldwell T. H. , Boyd D. A. 
Published: March 2009

SummaryThe fen silts bordering the Wash are among the most important soils for crop production in eastern England. Derived from marine alluvial deposits occurring naturally or as a result of reclamation, they form deep almost stoneless soils containing little coarse sand but much fine sand and silt.Seven textural classes, ranging from loamy fine sand to silty clay, can be distinguished, but these can be grouped into (1) light silts, typically deep very fine sandy loams with a large available water-holding capacity but weakly developed structure; (2) medium silts, silty loams; and (3) heavy silts, silt loams or silty clay loams, less porous and more retentive of moisture than the light silts.Formerly under grass, the silts were at first capable of growing good crops of potatoes with P fertilizer alone, but as their organic-matter content decreased, potatoes became increasingly responsive to N.In 18 potato manurial experiments on silt soils in Holland, Lincolnshire, done between 1953 and 1963, the mean response to N was much larger than on most English soils, but response differed greatly from site to site and year to year; in most trials N was particularly effective in increasing tuber size and yield of ware. With long-continued use of P fertilizer, residues have accumulated and, particularly on light and medium silts, responses were quite small and differed little between sites; P tended to increase tuber numbers, and so to decrease ware percentage. Most silt soils are rich in K, and only small responses to K fertilizer can be expected, but on a few sites on the light silts, identified by soil analysis as being comparatively poor in K, potatoes responded well. Using these experimental results, recommendations are given for the manuring of potatoes on silt soils.Cooking tests showed little consistent effect of manurial treatment on the amount or degree of tuber blackening.
Environmental and varietal differences in diastatic power and four associated characteristics of spring barley
Authors: Hayter A. M. , Riggs T. J. 
Published: March 2009

SummaryResults from two trials on spring barley varieties are presented. A factorial fertilizer trial estimated the effects of N, P and K at each of three levels on diastatic power, heat-stable alpha-amylase activity, grain nitrogen content, thousand corn weight and yield in a single variety. This revealed that the main effect of N was the most important source of variation. In a subsequent variety–nitrogen trial seven varieties were tested at each of three levels of N.In the variety–nitrogen trial, diastatic power was found to be positively correlated with both grain nitrogen content and alpha-amylase activity although these latter two variates were not themselves correlated. These observations were confirmed both within genotypes and within environments, and a hypothesis is advanced in explanation.The implications of the results for a breeding programme directed towards the production of high-yielding, high-diastase varieties are discussed.
The effects of red clover (Trifolium pratense var. redhead), white clover (Trifolium repens var. S 100) or perennial ryegrass (Lolium perenne var. S 23) on the reproductive performance of sheep
Authors: Newton J. E. , Betts J. E. 
Published: March 2009

SummaryDuring 3 years, three groups of 20 Scottish half-bred ewes were grazed on perennial ryegrass, white clover or red clover. During this period the two legumes were oestrogenic, in terms of teat-length extension of wethers, but the perennial ryegrass was not. The white clover was only markedly oestrogenic when there was a high proportion of diseased leaves. The mean litter size and lambing percentage of the ewes grazed on red clover was significantly reduced. White clover, although it was oestrogenic, had no effect on mean litter size or lambing percentage. The mean litter size of the ewes on the perennial ryegrass was 2·35, 2·30 and 2·24, on the white clover was 2·20, 2·33 and 2·23 and on the red clover was 1middot;60, 1·67 and 1·78 for the three lambings. Lambing percentage of the ewes on the perennial ryegrass was 175, 225 and 218, on the white clover was 210, 222 and 189, and on the red clover was 160, 128 and 118 for the three lambings. The lambing date of the ewes grazing on the red clover was significantly later at the third lambing.
The isolation of plant cell wall preparations with low nitrogen contents
Authors: Morrison I. M. 
Published: March 2009

SummaryGrasses of widely differing maturity have been extracted by two chemical and two enzymic methods in order to prepare cell wall materials with low nitrogen contents. These methods involved extraction, with neutral detergent or phenol-acetic acid-water (1:1:1), or digestion with the proteolytic enzymes pepsin or pronase. Wide differences were noted between these methods with grasses at different levels of maturity, both in the nitrogen content of the residue and the actual yield of cell wall preparation. The more efficient of these methods for removing nitrogenous materials, namely neutral detergent extraction and digestion with pepsin and pronase, were also examined for their effect on the structural carbohydrate and lignin content of the cell wall. In all respects, a method involving incubation with the enzyme, pronase, gave the most satisfactory cell wall preparation.
The effect of soil physical conditions produced by various cultivation systems on the root development of winter wheat
Authors: Finney J. R. , Knight B. A. G. 
Published: March 2009

SummaryThe results of a field experiment on winter wheat are presented in which the effects of the soil physical properties produced by different cultivation systems were studied in relation to root development.The extension rate of the seminal root axes was slower in undisturbed or shallow (5 cm) cultivated soil than in ploughed or deep (20 cm) cultivated soil leading to earlier lateral branching and the production of an effectively shallower seminal root system which persisted throughout the season. During the first four weeks after drilling the soil in the ploughed and the deeper cultivated plots was of lower bulk density and there were more pores of a diameter suitable for unimpeded root extension. It is suggested that seminal root development in uncultivated soils, which are less readily deformed than cultivated ones, is related to the probability of the extending seminal axes contacting pores of suitable dimensions.The implications of shallower rooting are discussed and related to field experience with cereal crops drilled directly into uncultivated soils where success has consistently been achieved on free-draining, open-textured soils.
Inhibition of muscle growth in foetal sheep
Authors: Swatland H. J. , Cassens R. G. 
Published: March 2009

SummaryEighteen foetal sheep were used to study the relationship between suboptimal growth and linear size of skeletal units, dry weights of representative muscles and muscle histology. Foetuses with suboptimal growth caused by inadequate maternal nutrition and competition with other foetuses showed a decrease in skeletomuscular growth although allometric growth was not affected. A slight correlation (r =0·14, P < 0·005) existed between dry weight of the longissimus dorsi and mean minimum myofibre diameter. On morphological evidence, myofibre hyperplasia was thought to be complete by approximately 80 days gestation in all foetuses. Increases in the number of myofibres crossing mid-length transverse sections of the sartorius occurred after this time but were thought to be due to intrafascicularly terminating myofibres growing in length. Suboptimal muscle growth of foetuses in the latter third of gestation was thought to be associated with an inhibition of growth in length of intrafascicularly terminating myofibres.
Preliminary study on the use of different methods for determining the proportion of bacterial nitrogen in the total nitrogen of rumen contents
Authors: Nikolić J. Anna , Jovanović M. 
Published: March 2009

SummaryThree different methods have been used to estimate the contribution of bacterial nitrogen to the total nitrogen in rumen digesta from calves receiving ground diets containing different levels of digestible energy and in which part of the nitrogen was supplied as urea. The method based on the ratio of 2, 6-diaminopimelic acid (DAP)-N to total N for rumen contents and rumen bacteria was not successful because the bacterial fraction isolated from pooled rumen contents contained a similar concentration of DAP to whole rumen digesta. The main source of error in the method based on the nucleic acid N/total non-NH3-N ratio for whole rumen contents and bacteria was probably the variability in the ratio for bacteria growing under different conditions. The method utilizing differences in the amino acid composition of the diets, a bacterial fraction and rumen content estimates bacterial protein rather than bacterial nitrogen. The chief limitation is the different rate of degradation of different dietary proteins. Bearing in mind these limitations calculations by the nucleic acid method gave mean values of 61–94 % bacterial nitrogen in the total nitrogen of rumen contents 3 h after feeding four different diets. Values recorded by the amino acid composition method varied between 66 % and 82 % bacterial protein N in the total protein N of rumen contents. The proportional contribution of bacteria increased as the digestible energy content of the diet was decreased in both cases. However, since the ruminal total protein N concentration fell as the digestible energy content of the diet was reduced, the actual concentration of bacterial protein N decreased with decrease in dietary digestible energy.
Growth rates of three cassava varieties (Manihot esculenta Crantz) under varying population densities
Authors: Enyi B. A. C. 
Published: March 2009

SummaryThe effect of variety and spacing on growth, development and yield of cassava and the relationship between growth, development and yield in three cassava varieties were investigated during the 1971 and 1972 growing seasons. Msitu Zanzibar outyielded Aipin Valenca and these two varieties in turn outyielded Amani 4026/16. The varietial effect was associated with differences in the rate of bulking. Increase in plant density led to an increase in the yield of tubers per hectare, the mean increase with increasing plant density being greater in Aipin Valenca than in either Amani 4026/16 or Msitu Zanzibar. Increase in plant density from 12000 to 18000 plants/ha led to a decrease in root tuber yield in Amani 4026/16. The calculated optimum density for maximum yield was 6·7, 6·4 and 5·6 plants/m2 respectively for Msitu Zanzibar, Aipin Valenca and Amani 4026/16. The spacing effect on tuber yield was associated with differences in the rate of bulking. Aipin Valenca was usually taller than the other varieties and, in general, increase in plant density increased the height of the plants.Final total dry matter/m2 was greater in Aipin Valenca and Msitu Zanzibar than in Amani 4026/16 and, with the exception of the last variety, total dry matter/m2 increased with increasing plant density. Total dry matter produced per plant was greater in Msitu Zanzibar than in Aipin Valenca and these two varieties had greater dry weight per plant than Amani 4026/16. In the three cassava varieties, the dry weight per plant increased with decreasing plant density.A greater proportion of the total dry matter was diverted into the root tubers of Aipin Valenca and Msitu Zanzibar than in Amani 4026/16. Generally, increase in plant density decreased the proportion of total dry matter diverted into the root tubers. Mean crop growth rate increased with increasing plant density while mean net assimilation rate and relative growth rate decreased with increasing plant density. Amani 4026/16 and Aipin Valenca had a greater mean crop growth rate and a greater net assimilation rate than Msitu Zanzibar. Mean relative growth rate was greater in the latter than in the former two varieties.Leaf area index and leaf area duration were greater in Msitu Zanzibar than in the other two varieties and these tended to increase with increasing plant density.There was a close and positive relationship between rate of bulking and root tuber yield and the lack of a positive relationship between leaf area duration and tuber yield is discussed.