bluuebunny/crossref_metadata_2025_split huggingface dataset:
The efficiency of seedling selection by visual preference in a potato breeding programme
Authors: Brown J. , Caligari P. D. S. , Mackay G. R. , Swan G. E. L. 
Published: March 2009

SUMMARYThe efficiency of visual selection in a glasshouse of 1600 seedlings compared with visual selection in the field of the same clones is examined. Also the amount of agreement in assessment between four different potato breeders screening the same clones is investigated. Seedlings were grown from true seed in four-inch pots in a glasshouse and all the clones which produced tubers were grown in the field the following year. Clones which produced more than one tuber from a seedling were grown at two locations in the first clonal year. One of the sites used in the first clonal year is normally used for potato yield trials (i.e. a ware site) and the other is normally used for the production of healthy seed tubers (i.e. a seed site). In all three environments, the tubers produced from each plant were assessed by four breeders independently on a 1–9 scale of increasing attractiveness.From the data it was found that the repeatability of assessment between the glasshouse and the first clonal year was low in that the correlation between the average preference score of the four breeders in the glasshouse and each of the two first clonal year sites accounted for only 8·24 and 6·84% of the total variation. Many clones which had low scores in the glasshouse were subsequently given high scores in the first clonal year. It was therefore concluded that selection of seedlings was not very efficient. Although, in general, the weight of the tuber that was planted greatly influenced whether a clone was selected in the first clonal year, a large number of clones which produced only small tubers in the glasshouse were subsequently selected in the first clonal year.Within each environment the four breeders were either all selecting, or all rejecting, a much higher proportion of clones than would be expected if selection had been made completely at random. The breeders were in most agreement when assessing clones at the ‘ware’ site, and in most disagreement when assessing them grown in the glasshouse from true seed. Therefore the poor efficiency of selection of seedlings grown in the glasshouse was not, in the main, a result of a high error variance in visual assessment but rather due to poor association between the performance of seedlings and first clonal year plants.
The concentrations of air-borne rape pollen over a crop of oil-seed rape (Brassica napus L.)
Authors: Williams Ingrid H. 
Published: March 2009

SUMMARYThe air over a crop of flowering winter oil-seed rape was sampled for 39 days with an automatic volumetric spore trap. Considerable quantities of rape pollen were caught on most days. Density of pollen showed marked diel periodicity; few grains were caught at night and at mid-day, peaks occurred in late morning and early afternoon. It is concluded that wind plays a considerable role in pollination of the crop.
Effects of fertilizer on root growth and water use of barley in northern Syria
Authors: Gregory P. J. , Shepherd K. D. , Cooper P. J. 
Published: March 2009

SUMMARYBarley (cv. Beecher) was grown at two sites (Jindiress and Breda) in northern Syria, chosen for their contrasting edaphic and climatic conditions. At both sites, three fertilizer treatments were applied zero (Z), 60 kg P2O5/ha (P), and 60 kg P2O5/ha with 60 kg N/ha (NP) and measurements made of shoot and root growth, and water use.The growth of crops not given fertilizer was similar at both sites and early growth was increased by the application of fertilizers. However, at maturity, yield was increased at Jindiress by giving N and P together, but not by P alone, while at Breda P alone increased yields but additional N produced no additional yield. There were marked effects of fertilizer on crop development at Jindiress; anthesis and maturity were about 14 days earlier in the NP treatment than in the Z treatment.Root growth was also affected by fertilizer applications and there were small but significant differences in growth between the sites. The proportion of root weight: total plant weight was greater than commonly observed in temperate cereals and there were substantial differences between the sites in the pattern of root distribution within the soil profile.The total amount of water used by the crops differed between the sites but was largely unaffected by fertilizer treatment at each site. Evapotranspiration during the winter when the soil was recharged with water was about 50% of the seasonal total. At Jindiress, the pattern of water extraction from the profile and the root distribution were similar before flowering but at Breda, there was no correspondence. Rates of water inflow varied with both site and time.Crop characteristics that may be associated with increased yields are discussed. Deeper, more extensive rooting is unlikely to be useful in such regions but rapid early growth of both shoots and roots may allow water to be used more efficiently.
Growth and development in the pig, with special reference to carcass quality characters. I
Authors: McMeekan C. P. 
Published: March 2009

1. With the object of establishing the general order of development during post-natal life of the body proportions, tissues, and anatomical units, the relative changes with age in these characters have been studied in a series of male pigs killed at monthly intervals from birth to 7 months. The study is to be regarded in the light of a preliminary investigation, providing a background to experimental studies on the influence of nutrition on the growth and development of the pig.2. Growth in body proportions, when measured both photographically and by the weight of the individual anatomical regions, conforms to the law of developmental direction, exhibiting a well-defined anterior-posterior gradient from earlier to later developing regions. The limbs appear as relatively early developing parts with the fore limbs slightly earlier developing than the hind.3. The major body tissues exhibit marked differential growth behaviour; skeleton, muscle, and fat develop in that order. This situation has its origin in the differential rates of growth of the three tissues, in consequence of which the earlier developing skeleton makes a greater proportion of its growth earlier in life than does muscle, while the latter makes a greater proportion of its growth earlier than does the still later developing fat.4. Within any one tissue, the individual anatomical units or regions of the body similarly show well-defined differential growth relationships. Thus, the skeletal units of the head and trunk exhibit an anterior-posterior gradient in their order of development, while the bones of each limb show a centripetal gradient, the upper units being later developing than the lower units. To an even more marked degree, both the muscle and the fat surrounding these skeletal units afford evidence of similar gradients in these tissues.
Electrode potentials in laboratory silage
Authors: Common R. H. , Bolton W. 
Published: March 2009

1. The average electrode potentials of laboratory silages of various types have been measured.2. The electrode potentials of ordinary and molassed silages tended to assume values of the order of –0·05 to –0·10 V. from about the third day; thepH of these silages lay in the rangepH 4·0 to 5·5.3. In a number of instances secondary increases of electrode potential were observed, frequently in association with secondary deterioration.4. The electrode potential of silage prepared with hydrochloric acid and ofpH 3·4 remained steady around +0·18 V.; the potential of silage prepared with formic acid and ofpH 3·9 was about + 0·35 V. initially but declined towards + 0·23 V. at 35 days.5. Curves for the ‘pure’ carotene content of laboratory silages displayed minima during the early stages of fermentation except in the case of formic acid silage.
Growth and development in the pig, with special reference to carcass quality characters: Part II. The influence of the plane of nutrition on growth and development
Authors: McMeekan C. P. 
Published: March 2009

No attempt will be made to give a detailed summary of all the findings of the present experiment. It is rather our purpose to draw attention to the main principles emerging.1. The influence of extremes of high and low planes of nutrition during the first 16 weeks of post-natal life upon the growth in body proportions and in anatomical composition has been studied experimentally in six pairs of closely inbred pigs. Quantitative differences in nutrition operative from birth have resulted in an average live weight at 16 weeks of 113 lb. in the High-Plane and 37 lb. in the Low-Plane animals.2. In body proportions, the head, ears, neck, legs, and body length are penalized relatively less by inadequate nutrition than are body depth, loin, and hindquarters. Conversely, good nutrition favours most the latter characters. These effects upon body form are similarly evident i n the gross weight of the different anatomical regions involved. Low-Plane animals to a large extent retain the proportions of the juvenile and High-Plane approach the conformation of the adult
Fractionation of nitrogen isotopes by animals: a further complication to the use of variations in the natural abundance of 15N for tracer studies
Authors: Steele K. W. , Daniel R. M. 
Published: March 2009

SUMMARYA study of the fractionation of nitrogen isotopes in the diet by cattle is described and the results discussed.Compared with the diet, urine had a lower ratio of 15N to 14N, but faeces, blood and milk all had a higher ratio.It is argued that the use of natural 15N as a tracer in grazed ecosystems is more complicated than was at first thought.
Efficiency of utilization of food energy by growing pigs
Authors: Burlacu G. , Iliescu Monica , Stavri Josefina 
Published: March 2009

SUMMARYThe efficiency of utilization of the energy of the food by growing pigs of the Large White breed was measured. Ten diets had a digestible energy varying from 75·3 ± 0·91 to 85·7 + 0·81% and a metabolizable energy from 72·3± ·92 to 83·4±0·64% of the gross energy. Net energy was 85·2±3·20% of the metabolizable energy (ME).Regression calculations resulted in the following estimates: a maintenance requirement of 151 kcal ME for growing pigs weighing 9–58 kg and efficiencies of 66·7 and 100% for the utilization of ME for protein and fat accretion, respectively.Feeding regime (ad libitum or restricted at about 80% ad libitum) did not influence food utilization.
Results from experiments measuring the effects of large amounts of fertilizer and of farmyard manure on main-crop potatoes grown in sandy soil at Woburn, Bedfordshire
Authors: Widdowson F. V. , Penny A. , Flint R. C. 
Published: March 2009

SUMMARYThe largest yields of potatoes in the Woburn Reference Experiment were obtained by giving both farmyard manure (FYM) and fertilizers, rather than fertilizers alone; an explanation was sought in experiments made on the coarse sandy loam there from 1968–71. Each year, single and double amounts of NPK fertilizer (supplying 250 or 500 kg N/ha plus P and K) were incorporated, either deeply or shallowly, into the seed bed. From 1969, FYM also was tested at rates giving the same amounts of N, similar amounts of K, but more P than the fertilizers; it was tested both alone and with fertilizers.FYM was less effective than fertilizer when given alone. The combination of FYM and fertilizer gave a larger yield than the single amount of fertilizer and a larger yield than the double amount of fertilizer incorporated shallowly, but a smaller yield than the double amount of fertilizer incorporated deeply, which gave the largest yield each year.The NPK contents of the potato tubers were used to construct nutrient balance sheets; large residues of N, P and K remained in the soil after harvest. Winter wheat was grown to value these in 1971 and 1972. Fertilizer residues increased only straw yields, but FYM residues increased yields of both grain and straw. Both kinds of residues were less effective than freshly applied N, so most of the N leached during winter.The yield of saleable tubers was increased, not decreased, by the double amount of fertilizer.
Compressibility curves as a quantitative measure of soil tilth, II
Authors: Blair G. W. Scott , Cashen G. H. 
Published: March 2009

1. The method described in an earlier paper for measuring the compressibility of soils in situ has been used to study the gradual consolidation of soil following digging with a fork, and a new method in which the rate of flow of water through rubber tubes buried in the soil gives a measure of compression, is described.2. By means of this latter method some measure can be obtained of the changes that take place in the soil after it has been loaded and trampled.3. The results of the experiments confirm and amplify the earlier conclusions. Without further data it is hard to distinguish quantitatively the effects of moisture and time, but it is of interest that whereas the compressibility of newly dug soils is hardly affected by differences in moisture for the range of stress used, that of soils which have rested for some time since cultivation is much increased by an increase in moisture content.4. Experiments on a wider scale should be undertaken in order that a more complete analysis may be effected.
The digestion of huskless oats by poultry
Authors: Moon F. E. , Thomas Brynmor 
Published: March 2009

The digestibility for poultry of a variety of huskless oats recently placed on the market has been investigated, and a comparison made with a widely grown variety of more usual fibre content.It was shown that the fibre of the huskless oats was completely undigested, while that of the control variety had a digestibility coefficient of 8·8 per cent.The digestibility of the crude protein in huskless oats was higher than in the variety Victory. It is suggested that this difference has resulted from the same cause as that which operates in ruminants, whereby fibre has a depressant effect on protein digestibility.Both the organic matter and N-free extract were digested to a greater extent in the huskless oats than in the control variety. This is in keeping with the findings of other workers on the relation between fibre content and the digestibility of these constituents.
Note on the effect of temperature on a mixed culture of two organisms in symbiotic relation
Authors: Richards E. H. 
Published: March 2009

1. A study was made of nitrogen-fixation byAzotobacter chroococcumalone in a medium containing dextrose (which it can utilize) and in mixture with a coliform organism on a medium containing no carbohydrate except starch, whichAzotobactercannot utilize unless it be hydrolysed by the coliform organism or some other agency.2. The amount of nitrogen fixed in the mixed cultures was found to be maximal at two temperatures, and a discussion is given of the causes thought to be operative in producing the double maximum.
The base status of Scottish soils: II. Further studies of the effects of lime on typical soils from north-east Scotland
Authors: Whelan L. A. 
Published: March 2009

An investigation into the effects of lime on five acid soils in north-east Scotland has been continued during the second and third years after the application of lime and also extended to two other centres.On four of the original soils the full effect of the lime on the surface soil has been largely maintained up to the end of the third year. The fifth, a soil of low base-exchange capacity, shows a considerable loss of lime by the end of the second year.The lime leached from the top nine inches of soil appears to be retained to only a slight extent in the second nine inches. This was particularly noticeable on a soil of low base-exchange capacity, where, during the two years after liming, the percentage saturation of the subsurface soil showed an increase from 64 to 67%, and the surface soil a decrease from 92 to 74%.The existence of a low liming factor (1·5), previously found to hold for a geologically basic soil, has been verified and found to apply also to a soil derived from slate.A fundamental property of the soils with a low liming factor is the high content of inorganic and organic fine material. Secondary characteristics that distinguish these soils from the others are the relatively high values for hygroscopicity and heat of wetting.
Meat qualities in the sheep with special reference to Scottish breeds and crosses. I
Authors: Pálsson H. 
Published: March 2009

1. By establishing the relationship between linear carcass measurements and the quantitative composition of the carcass in terms of bone, muscle and fat, we have provided a scientific basis for the use of many measurements hitherto only presumed to provide an index to carcass quality.2. External carcass measurements are correlated with weight of the skeleton. The most useful for this purpose are length of tibia + tarsus and length of the fore-cannon.3. As indices of muscle, external measures are only of indirect value. Thus, both F – T and G/F × 100 are strongly correlated with weight of muscle as a percentage of skeletal weight.4. Similarly, F provides an index of fat, being negatively correlated with fat as a percentage of bone.5. For muscle and fat internal measures permit a more precise estimate to be made. A + B is the best index of the former while C + J + Y provide the most accurate estimate of the weight of fat.6. Still better indices for muscle and fat are provided by suitable combinations of external and internal measurements. Thus L/10 + A + B is very highly correlated with the weight of muscle, and L/10 × (C + J + Y) is the best index of fat in the hoggets. For bone, a most efficient single index is shown to be the weight of the fore-cannon bone.7. The weight of the skeleton can be estimated with a high degree of accuracy from the weight of the bones in either one leg or loin. Both these joints combined, however, provide a still better estimate.8. The muscle in one leg or loin + leg provides an excellent index of the weight of muscle in the whole carcass.9. The fat in one leg, loin, or both these joints combined provides a good index of the weight of the total fat in the carcass. Both joints combined give the most precise measure.10. The value of certain measurements which are not necessarily associated with the quantity of the major tissues of the carcass, but which nevertheless have important qualitative significance, is emphasized.
Reproductive performance of Merin, sub-tropical Egyptian sheep and their crosses
Authors: Aboul-Naga A. M. 
Published: March 2009

SUMMARYEwe reproductive traits of imported Merino local Ossimi and Barki, their first crosses, backcrosses to Merino and the interbred groups of the backcrosses, were considered in this study. Records of 2168 ewes born from 1960 through 1970 were used in the study; they totalled 6959 records.Reproductive performance was different in the three purebred groups, with more multiple births but more lamb losses and abortions in Merinos. However, the three groups weaned similar numbers of lambs/ewe run with the rams (0·98). Merino × Ossimi ewes had the best performance, they lambed and weaned 27% more lambs than local Ossimi. They were followed by MB ewes weaning 0·96 lambs/ewe run with the rams. Reproductive performance of the backcross ewes was lower than that of the first cross, but still better than the purebred groups. Inter-breeding of back-crosses reduced their hybrid vigour markedly.Non-maternal heterosis contributed greatly to the reproductive performance of cross-bred ewes, while the effect of maternal heterosis on reproductive traits was fairly small.Multiple births showed least heterotic effect.
The limiting effect of plant size at inflorescence initiation on subsequent growth and yield of oilseed rape (Brassica napus)
Authors: Mendham N. J. , Scott R. K. 
Published: March 2009

SUMMARYA substantial loss in yield usually occurs when oilseed rape is sown later than mid-September. Field experiments in 1972–3 tested whether this is because all plants, irrespective of size, initiate inflorescences during the winter, thus restricting the eventual size of the leaf canopy and the yield potential of late-sown plants, which are still very small when the change to the reproductive phase occurs.Sowing a standard winter variety, Victor, from mid-August to mid-October resulted in initiation occurring from late October to February. When sown after mid-September yields were proportional to plant size at initiation. The winter was mild, and in colder conditions earlier sowing may be required to enable plants to reach a critical size before initiation takes place. When sown in August plants were very large but yield was not improved. A study of the development of the pod canopy showed that the extra yield potential was not realized because heavy losses of pods and seeds occurred, particularly in the more shaded positions.When a range of winter varieties, chosen to contrast the timing of phasic development, was sown on two dates yield was proportional to the interval between sowing and initiation, particularly when late sown, presumably because late initiators were able to lay the foundation of a more substantial root and shoot system. This has implications for plant breeding programmes because the low erucic acid varieties currently being grown initiate inflorescences early. When spring types were sown in mid-October they formed floral initials very early, and gave particularly small and weak plants, with a low yield. Winter types sown in March did initiate flowers and produce large plants, but yields were no better than spring types as flowering and ripening were irregular and late, the cold requirement for initiation being only marginally fulfilled.
The effect of ammonium sulphite on plant growth
Authors: Lewis A. H. , Marmoy F. B. 
Published: March 2009

Summary and ConclusionsA review of the literature gave conflicting evidence as to the effect of sulphites on plant growth, so that a pot culture experiment was conducted to study the effects of the addition to ammonium sulphate of varying amounts of ammonium sulphite on the germination, growth and yield of mustard and rye on a heavy loam soil.Under the conditions of the experiment described, ammonium sulphite had no adverse effect on the germination, growth and yield of dry matter of mustard or rye.
A study of the exchangeable bases of some East Anglian soils derived from the Jurassic and Cretaceous sediments, with special reference to their marine origin
Authors: Salgado M. L. M. 
Published: March 2009

Summary1. The results are recorded of an investigation of the exchangeable bases of some East Anglian soils derived from the Oxford, Ampthill, Kimeridge and Gault formations of the Jurassic and Cretaceous ages.2. As they were formed under the sea the original sediments contained sodium-clays but on the return of terrestrial and fresh-water conditions the character of the deposits was completely changed and they now contain only traces of exchangeable sodium.3. In the unweathered clay, represented by the 2 ft. below the top 18 in., exchangeable calcium forms only 75 per cent. of the total, and magnesium 20 per cent. As a result of leaching and weathering the magnesium on the surface is replaced by calcium which in the top 18 in. forms 85 per cent., while the magnesium is only 10 per cent. Thus the surface and deeper soils are distinguished by characteristic calcium: magnesium ratios.