bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effects of Different Traditional Sources of Nutrients on the Infestation of Pepper Fruits by the Pepper Fruitfly, Atherigona orientalis (Schiner), in Nigeria
Authors: Ogbalu O. K.
Published: March 2003

Experiments were conducted in 1995 and 1996 to determine the effects of different sources of nutrients on the infestation of fruits of five pepper varieties by Atherigona orientalis (Schiner). Different sources of nutrients — chicken droppings, plant residues (compost manure), wood ash and NPK (chemical fertilizer) — were used in the planting of each of the five pepper varieties [Nsukka yellow, Atarugu, and Sweet pepper, all of Capsicum annum; Bird’s eye chilli and Local medium red (Ogoni pepper) both of C. frutescens]. In 1995 plantings, pepper plots of Nsukka yellow and Atarugu varieties that received chicken droppings as source of nutrients suffered the highest percentage fruit damage of 90.7 % and 80.8 %, respectively. Pepper plots of Nsukka yellow, Atarugu, Sweet pepper and Local medium red grown in 1996 and treated with chicken droppings suffered the highest percentage fruit damage of 93.7 %, 56.6 % and 52.2 %, respectively. Plots of the Bird’s eye chilli variety received minimal or no fruit damage in all. Pepper fruits in the control plots also did not undergo A. orientalis attack. Chicken droppings offered the lowest Relative Protection (RP) values to most pepper varieties in 1995 and 1996. NPK chemical fertilizer offered the highest percentage RP values in 1995 and wood ash offered the highest RP in 1996 to most pepper varieties. Also, wood ash in both 1995 and 1996 offered a relatively high percentage RP to most pepper varieties. Compost manure offered a moderate percentage RP in both years.
Cover Crops for Saline Soils
Authors: Mitchell J. P. , Thomsen C. D. , Graves W. L. , Shennan C.
Published: March 2003

A 3‐year study was conducted in the Central Valley of California to evaluate 125 prospective winter‐growing cover crops for growth and nitrogen productivity in saline soils. Soil saturation paste electrical conductivities (ECes) in the surface 15 cm averaged 7 dS  m−1 at fall planting and 5.3 dS m−1 at spring harvest dates of each experiment. Species evaluated varied substantially in plant height. In general, the tallest plants were the Brassica species, which consistently grew to over 1.4 m. Annual grasses (barley, rye, triticale and wheat) averaged about 1.0–1.3 m in each year. Of the legume species screened, heights were greatest for Hedysarum coronarium, Trifolium alexandrium, Vicia spp., and Medicago polymorpha and truncatula, averaging 59, 47, 39, 38 and 37 cm, respectively, over all experiments. About one third of the species screened produced crop cover in excess of 90 % in each year. Groups of plants with consistently high crop cover percentages included various species/accessions of Brassica, Hedysarum, annual grasses, cool‐season annual medics, Medicago polymorpha and Medicago truncatula, and two annual clovers, Trifolium alexandrium cv ‘Multicut’ and rose clover, Trifolium hirtum cv ‘Hykon.’ Total above‐ground plant dry weights were highest for Brassica spp., which produced twice as much biomass as the annual grass species, and roughly four times as much dry matter as any of the legume species. Hedysarum, Lana and Namoi woolypod vetch, purple vetch, berseem clover, and several of the annual medic species consistently had the highest biomass among the legumes.
Comparative Responses of Wheat (Triticum aestivum L.) Cultivars to Salinity at the Seedling Stage
Authors: Rashid A. , Qureshi R. H. , Hollington P. A. , Wyn Jones R. G.
Published: March 2003

Seedling growth and ion content of Pakistani bread wheat cultivars was assessed in solution culture in the absence and presence of NaCl (100 and 200 mol m−3) to determine whether seedling traits could be used in breeding programs for salt‐tolerance. Growth was recorded as seedling fresh weight, and the shoot and leaves analysed for major inorganic ions. Plants subjected to salt stress excluded Na+ and Cl− ions from the shoot to varying extents. Exclusion preferentially maintained lower Na+ and Cl− levels in the apical tissue, as the leaf to leaf gradient in Na+ and Cl− became steeper as the external salinity increased, although there were significant differences between cultivars. Correlation analysis on individual plants indicated that excluding Na+ at low salinity, and Na+ and Cl− at high salinity, were correlated significantly with growth performance, although it was clear that other factors were also involved. The relationship of tolerance to ion exclusion was stronger when the data were examined on an individual plant basis than when related to pooled cultivar data or to the cultivar rank order derived from field trials, probably due to large variations in Na+, and to a lesser extent, Cl− transport in supposedly homozygous cultivars.
Vegetative Performance of Tropical Highland Maize (Zea mays L.) in the Field
Authors: Stehli A. , Soldati A. , Stamp P.
Published: March 2003

Introgression of tropical highland germplasm may assist in broadening the genetic base of maize, with the goal of improving early seedling vigour in cool spring weather. To gain acceptance by breeders, this trait must be combined with reliable growth performance at late vegetative growth stages in warm summers. At three locations, to the south and north of the Swiss Alps, five field experiments were carried out with eight adapted varieties or semi‐exotic highland varieties in 1991 and 1992. Temperatures in late spring and early summer were generally above the meteorological average at all locations, so the data are mostly described on an average basis. In comparison to the means of all varieties, exotic germplasm improved the early seedling vigour at the heterotrophic phase, showing a greater relative advantage in cool spring weather, whereas the ranking of relative growth rates (RGR) decreased steadily during the autotrophic growth phase until anthesis. At the early autotrophic stage a comparatively low leaf area ratio (LAR) of exotic germplasm was mainly responsible for a low RGR, despite high net assimilation rates (NAR). Thus, the early growth advantage was lost by anthesis. Although one variety with just 12.5 % exotic germplasm combined satisfactory early vigour with a good growth potential at later stages, the causes of the heat sensitivity, a disadvantage of tropical highland germplasm, have to be better understood before this germplasm can be directly used for breeding purposes.
Results of Long‐term Experiments with Growing Flue‐cured Tobacco (Nicotiana tabacum L.) in Monoculture and Different Types of Crop Rotations
Authors: Butorac A. , Turšić I. , Butorac J. , Mesić M. , Bašić F. , Vuletić N. , Berdin M. , Kisić I.
Published: March 2003

In broadly conceived long‐term experiments, tobacco was grown in monoculture and with different crop rotations. This paper presents results in terms of the yields achieved and the major yield components for the crops grown, and the proportion of particular tobacco quality classes obtained. In addition to tobacco monoculture (initially only fertilized and later also unfertilized) as the key crop, different types of crop rotations included, besides tobacco, the following crops: winter wheat, maize, soybean, oil‐seed rape, and red clover. Experiments involved two 2‐year and two 4‐year crop rotations, and a 3‐year, a 5‐year, and a 6‐year crop rotation. Experiments were set up on luvic semigley on multilayered Pleistocene sands. Average 10‐year results suggest that there is an advantage of crop rotation over monoculture for tobacco leaf yields. The influence of different crop rotation types on yields of other crops was variable, tending towards higher values as the number of crops in rotation was increased. Values obtained for yield components should be considered from two angles: some of the values were primarily influenced by genetic factors, while others were influenced by ecological factors, including crop rotation as an overall biological buffer. With regard to quality classes (IB‐III), the growing of flue‐cured tobacco in crop rotation represents a great advancement relative to its growth in monoculture, even in a narrower crop rotation.
Effects of Plant Population Density and Intercropping with Soybean on the Fractal Dimension of Corn Plant Skeletal Images
Authors: Foroutan‐pour K. , Dutilleul P. , Smith D. L.
Published: March 2003

Three‐year field experiments were conducted to determine whether the temporal pattern of fractal dimension (FD) for corn (Zea mays L.) plant structure is altered by plant population density (PPD) or intercropping with soybean [Glycine max. (L.) Merr.], and how changes in the FD are related to changes in other canopy characteristics. Plants in monocropped corn and intercropped corn–soybean plots were randomly sampled and labelled for later identification. Corn plant structure was photographed from the side that allowed the maximum appearance of details (perpendicular to the plane of developed leaves) and from two fixed sides (side 1: parallel to the row and side 2: perpendicular to the row). Images were scanned and skeletonized, as skeletal images provide acceptable information to estimate the FD of plant structure two‐dimensionally by the box‐counting method. Differences in the FD estimated from images taken perpendicular to the plane of developed leaves were not significant among competition treatments. An adjustment of corn plants to treatments, by changing the orientation of the plane of developed leaves with respect to the row, was observed. Based on overall FD means, competition treatments were ranked as: high > normal ≈ intercrop ≈ low for side 1 and intercrop > low ≈ normal > high for side 2. Leaf area index (LAI) and plant height had a positive correlation with FD. In contrast, light penetration had a negative correlation with FD. In conclusion, FD provides a meaningful and effective tool for quantifying corn plant structure, measuring the structural response to cultural practices, and modelling corn plant canopies.
Effect of Sowing Technique on Growth of Undersown Crop and Yield of Spring Barley
Authors: Känkänen H. J. , Mikkola H. J. , Eriksson C. I.
Published: March 2003

Undersowing a main crop enables establishment of a catch crop in areas characterized by a short post‐harvest period before the onset of winter. Techniques with lower costs than conventional undersowing by separate drilling are often regarded as unreliable. Undersowing by drilling after sowing spring barley (Hordeum vulgare L.) was compared with broadcast sowing simultaneously with drilling barley. Various implements were coupled behind the combined drill in cases where seed was broadcast: a press‐wheel attachment, a long‐tined harrow and a cage roller. A fourth treatment did not include an implement coupled behind the drill. The undersown crop was sown as a seed mixture of 3 kg ha–1 red clover (Trifolium pratense L.) and 6 kg ha–1 meadow fescue (Festuca pratensis Hudson). The numbers of plants and weeds and the plant height were measured five times during the growing season. Above‐ground biomass of the undersown species was determined at barley harvest and in late autumn. Grain yield of spring barley was recorded. Drilling resulted in the highest yield of undersown crop when an early summer drought occurred, but broadcasting in combination with use of seed covering equipment led to the least variation in biomass production over the 4 years the experiment was conducted. The relative proportion of meadow fescue in the crop was low in three years, and lower when broadcast than when drilled. Barley grain yield was highest when the seed was broadcast and seed covering equipment was used. Use of a cage roller increased weed biomass, but press‐wheels and a long‐tined harrow did not. Separate rolling after undersowing increased undersown crop yield in one year, but decreased grain yield in some cases.
Ecophysiology of the Plant–Rhizosphere System
Authors: El‐Shatnawi M. K. J. , Makhadmeh I. M.
Published: March 2003

The rhizosphere is the site of organic deposition and the generator of habitat and resource heterogeneity for soil organisms. Plants can modify their rhizosphere through nutrient, moisture and O2 uptake from the rhizosphere, rhizo‐deposition and production of root exudates. As a result, rhizosphere chemical (pH, nutrient solubility, O2, CO2 and other chemicals), physical (moisture and aeration), and biological (soil pathogens, beneficial microorganisms and allelopathy) characteristics will be changed or modified. Rhizosphere microorganisms have positive or negative effects on plant growth and morphology by affecting the plant hormone balance, plant enzymatic activity, nutrient availability and toxicity, and competition with other plants. Plants modify the rhizosphere and as a result will modify the community.
Perchlorate is Not a Common Contaminant of Fertilizers
Authors: Hunter W. J.
Published: March 2003

Perchlorate consumption can cause mental retardation and tumour formation in humans. Recent suggestions that perchlorate may be present as a contaminant in fertilizers and fertilizer components have caused concern in the fertilizer industry. The present study developed methods for improving the HPLC analysis of perchlorate and used these methods to survey 15 US fertilizers for perchlorate. Extraction with 50 mM NaOH rather than water was found to improve extraction efficiency from 84 to 98%. The incorporation of Ca(HO)2 into the extraction medium to yield 1 : 0.5 or 1 : 1, SO4– : Ca+2 molar ratios reduced the analytical interference caused by SO4–2 by reducing the slope of the SO4–2 peak tail by ∼75%. The study found no perchlorate in any of the fertilizers investigated.
Resin‐Extractable Phosphorus, Vanadium, Calcium and Magnesium as Factors in Maize (Zea mays L.) Yield
Authors: Olness A. , Archer D. W. , Gesch R. W. , Rinke J.
Published: March 2003

Resin extraction of soil permits evaluation of ratios of readily extracted elements and correlation of concentrations obtained with crop yield. This information provides guidance on potential genotype selection and fertility management. Two hybrids of maize (Zea mays L.), designated 2292 and 3895, were grown annually in rotational succession on a 3.2‐ha site with soybean (Glycine max L.) and wheat (Triticum aestivum L.). Soil samples (0–15 cm) were extracted with ion‐exchange resins and extracts were analysed with inductively coupled plasma. Data were regressed against crop yield using stepwise multiple correlation methods. Each hybrid was sensitive to unique combinations of extracted chemistries. Both hybrids of maize were sensitive to the resin‐extractable V : (V + P) molar ratio and potential losses of ≥ 20 % were indicated as the ratio approached 0.2. A positive response to the Mg : (Mg + Ca) resin‐extractable ratio was noted for maize hybrid 2292 in each of three successive years. Changes of yield potentials associated with the Mg : (Mg + Ca) ratio for hybrid 2292 ranged from none to ≥ 20 % as the ratio ranged from 0.2 to about 0.8. The results indicate that, in the presence of large extractable concentrations of competing or inhibitory ions, different approaches to nutrient management in the form of fertilizer nutrient analysis, application, and genotype selection are needed to overcome effects of competing ions.
Response of Barley to Herbicide Versus Mechanical Weed Control Under Semi‐Arid Conditions
Authors: Tawaha A. M. , Turk M. A. , Maghaireh G. A.
Published: March 2003

A 2‐year field study was conducted during the rainy seasons of 1999 and 2000 at Houfa in northern Jordan, to study the performance of two barley genotypes (CWB117‐77‐9‐7//Alpha/Durra and Wiesellburger/Ahor1303‐61) and their response to hand‐weeding (practised monthly during the growing seasons) and application of the pesticide 2,4‐dichlorophenoxy acetic acid (2,4‐D) at different growth stages. CWB117‐77‐9‐7//Alpha/Durra gave significantly higher grain yields of 1214.5 and 1362.5 kg ha−1 during 1999 and 2000, respectively. Differences in weed number and fresh weight were significant amongst various treatments in both seasons. Hand‐weeding proved to be the better weed control method. In both growing seasons, yield reductions occurred when 2,4‐D was applied to barley at stage 11–18 (leaves 1–8 unfolded) and stage 43 (mid‐boot). The hand‐weeding treatment was more effective than 2,4‐D applications in suppressing weed growth.
Growth and Development of Wild Oat and Dual‐Purpose Barley Seedlings
Authors: El‐Shatnawi M. K. J. , Makhadmeh I. M.
Published: March 2003

Wild oat (Avena fatua L.) and dual‐purpose barley (Hordeum spontaneum L.) are native species that grow in many parts of Jordan. We compared seedling growth and development of wild oat and dual‐purpose barley in pots under field conditions. The seedling fresh root volume (cm3), root oven‐dry weight (g), shoot oven‐dry weight (g) and dry root weight to dry shoot weight ratio of both species were evaluated at ages 20, 40, 60, 80 and 100 days after emergence (DAE). Seedlings of the two species at 20 and 40 DAE had similar fresh root volumes and weights. At 60 DAE, the root volumes of barley and oat increased to 2‐ and 3‐fold the volumes at 40 DAE, respectively. By 80 DAE, root volume had increased to 13.6 and 10.2 cm3 for wild oat and dual‐purpose barley, respectively. At 100 DAE, the root weight of dual‐purpose barley significantly (P ≤ 0.01) decreased to 1.1 g, whereas wild oat root weight did not change significantly. Wild oat showed a slightly higher root/shoot ratio at 20 DAE than dual‐purpose barley (0.88 for wild oat compared to 0.70 for dual‐purpose barley). At 60 and 80 DAE, both species showed a reduction in root/shoot ratio, and this reduction increased at 100 DAE (0.46 and 0.33 for wild oat and dual‐purpose barley, respectively). Our data indicate that the growth and development of the two grass species follow similar patterns.
Comparison of European Fibre Flax (Linum usitatissimum) Cultivars under Eastern Canadian Growing Conditions
Authors: Couture S. J. , Asbil W. L. , DiTommaso A. , Watson A. K.
Published: March 2003

Renewed interest in natural fibres, decreasing subsidies to European producers, and high production costs have led the move to reintroduce fibre flax (Linum usitatissimum L.) production into eastern Canada. Research was conducted at the Macdonald Campus of McGill University, Québec, Canada in 1998 and 1999 and at Winchester and Kemptville, Ontario, Canada in 1998, to assess the performance of seven European fibre flax cultivars. Parameters evaluated included plant density, branching ratio, stem diameter, fresh and dry biomass, and mean harvest height. Data from all sites and years were subjected to a pooled anova where appropriate. The cultivar main effect was detected for all parameters measured, with the exception of mean fresh weight and mean height at harvest. There was also a site main effect for all parameters except for branching ratio. A cultivar–site interaction was found for all parameters except for mean stem diameter and mean dry weight. Results indicate a strong potential for producing fibre flax in eastern Canada using currently available European cultivars.
Assortative mating and other observations based upon the relationship between true and apparent breeding values in the Australian thoroughbred
Authors: Williamson By S. A. , Beilharz R. G.
Published: March 2003

Studies of heritability in thoroughbred populations are confounded somewhat by the presence of assortative mating. Although assortative mating itself will not make great changes to the magnitude of the assessment of heritability, it can exert a significant impact upon the accuracy of any conclusions made from the study. In order to remove the effects of assortative mating from the data available, use was made of the best linear unbiased predictor (BLUP) method. This procedure was followed using two combinations: sire and dam, and sire and damsire. Due to the size of the datasets it was not possible to directly solve the matrices produced; instead they were solved by approximation over fifty iterations.
Lack of evidence for bovine Y‐chromosomal variation in beef traits. A Bayesian analysis of Simmental data
Authors: Reinsch By N. , Engellandt T. , Schild H. ‐J. , Kalm E.
Published: March 2003

Introduction

Y‐chromosomal loci are genetically responsible for some male‐specific biological processes. The sex determining region Y (SRY), a protein with DNA‐binding activity, is known as the trigger for sex differentiation in mammals. In humans the SRY is encoded by a single exon located on the short arm of the Y chromosome, close to the pseudoautosomal boundary (S inclair et al. 1990). Moreover, the Y chromosome harbours the male‐specific histocompatibility antigen (reviewed by S
impson et al. 1997) and there are at least two regions of the Y chromosome, which have been shown to be essential for normal spermatogenesis in mice (E
lliott and C
ooke 1997).

The sexual dimorphism of aggression in mice has led to a search for its foundation on the Y chromosome. The existence of Y‐chromosomal genetic variation for aggressiveness with genetic factors borne both on the pseudoautosomal (YPAR) and on the nonpseudoautosomal (YNPAR) region of the Y chromosome (S luyter et al. 1996) has been shown. Another example for Y‐induced genetic variation in mice is the testis autosomal trait (occurrence of ovaries or ovotestes in XY animals), which is observed when specific Y chromosomes interact with the autosomal background of certain laboratory mouse lines (E
isner et al. 1996). A comparison of the resemblance of different types of relatives indicated a nonzero Y‐chromosomal variance for body weight in mice (B&
uuml;
nger et al. 1995).

In cattle the Y chromosomes of the Bos taurus and Bos indicus subspecies can be morphologically distinguished: its shape is submetacentric in B. taurus and acrocentric in B.indicus. This difference is caused by a pericentric inversion (G
oldammer et al. 1997) and has frequently been used to investigate the introgression of zebu genes into B. taurus breeds.

The polymorphism of the bovine Y chromosome itself and the results of mouse research both direct the scientific curiosity on the possible contribution of the bovine Y chromosome to quantitative genetic variation in cattle, a question which, to the authors’ knowledge, has not been investigated before. In this paper we first discuss the contribution of autosomal, imprinted, and sex‐linked genes to the resemblance of full and half sibs and then present a Bayesian estimation of a Y‐chromosomal variance component for each of four beef traits in young Simmental bulls using mixed linear and threshold models.
Variance of actual inbreeding derived from the number and variance of chromosome segment
Authors: Oikawa By T. , Sato K. , Takahashi S.
Published: March 2003

Introduction

The inbreeding coefficient (F) is used as a central parameter inferring a proportion of alleles identical by descent within an individual and by genetic variability within a population. The actual inbreeding coefficient varies around a central value, the inbreeding coefficient. C
ockerham and W
eir (1983) derived the method for computing the variance of inbreeding while reviewing several other methods. The variance of inbreeding in their report was considered to be of two components: one within population and the other between population of varied pedigrees. If pedigree is fixed, F is easily computed for an individual by the standard method (F
alconer 1989). For domestic animals, pedigree information is usually available because it is requisite for a programme of genetic improvement. In this study, the variance of inbreeding coefficient was derived for an individual with a pedigree having a single path to a foundation animal.
Use of marker haplotypes to refine covariances among relatives for breeding value estimation
Authors: Pagnacco  , Jansen
Published: March 2003

Markers flanking DNA regions, where quantitative trait loci (QTL) have been previously spotted, can be used to trace the common inheritance of major genes for a better definition of covariances among animals. A practical approach to the use of marker data to refine the additive relationship matrix used in the traditional best linear unbiased prediction (BLUP) methodology is presented. The technique allows the number of the mixed model equations to be kept to an animal level, blending polygenic pedigree data with marker haplotype information. The advantage of this marker‐assisted selection (MAS) approach over BLUP selection has been assessed through a stochastic simulation. A finite locus model with 32 independent biallelic loci was generated with normally distributed allelic effects. The heritability of the trait, measured on both sexes and on females only, was set to 0.2 and 0.5. Five‐allelic markers 2, 10 and 20 cM apart, bracketed the QTL with the largest effect on the trait, accounting for 17% of the genetic variance. The bracketed QTL had two or eight alleles and its position was undefined within the bracket. Results show a moderate 2% advantage of MAS over BLUP in terms of higher genetic response when trait was recorded on both sexes and heritability was 0.2. The benefit is in the short term, but it lasts longer with polyallelic QTL. When the trait was recorded on females only, MAS produced only a small and insignificant genetic gain, but reduced the overall inbreeding in the population. MAS was also inefficient when heritability was 0.5.
(Co)variance components, genetic parameters and annual trends for calf weights in a pedigree Brahman herd under selection for three decades
Authors: PLASSE D. , VERDE O. , FOSSI H. , ROMERO R. , HOOGESTEIJN R. , BASTIDAS P. , BASTARDO J.
Published: March 2003

A 300 cow Brahman herd kept on improved pasture was subjected to a selection and management programme based on a limited breeding season. Artificial insemination using mainly progeny tested bulls was used in part of the herd and the rest were bred in single sire herds. Of the 200 sires used during the 30 year period, 82% were homebred and selected principally for high estimated breeding value of 18‐month weight. Variance components of birth (BW), weaning (205 W) and 18‐month (548 W) weights of 6130 calves born 1968 through to 1997 were estimated by the Restricted Maximum Likelihood method (REML) using uni‐ and bivariate animal models. For each weight the animal's direct and maternal genetic and the dam's permanent environmental effects were considered random and those of sex, year and month of birth and age of cow were considered fixed, but the models differed as far as the number of significant interactions included. Adjusted least squares means for BW, 205 W and 548 W were 28, 158 and 292 kg. Phenotypic and direct and maternal genetic trends from univariate analysis were for BW: 0.156, 0.061 and −0.001 kg; for 205 W: 0.471, 0.126 and 0.044 kg; for 548 W: 1.973, 0.486 and 0.251 kg per year. Direct and maternal heritabilities from univariate analyses were for BW, 205 W and 548 W, 0.33 and 0.08; 0.07 and 0.14; 0.13 and 0.08, respectively. Genetic direct‐maternal correlations for the three weights were −0.37, −0.13 and 0.49 and permanent environmental variance of the dam as proportion of phenotypic variance (c2) had values of 0.03, 0.16 and 0.01, respectively. Direct and maternal genetic correlations were for BW: 205 W, 0.64 and 0.74; for BW: 548 W, 0.35 and 0.74; and for 205 W: 548 W, 0.64 and 0.96. Future genetic work in the herd should put more emphasis on the improvement of cow efficiency for sustainable beef production on native and improved pasture.
Multiple QTL on chromosome six in dairy cattle affecting yield and content traits
Authors: FREYER G. , KÜHN C. , WEIKARD R. , ZHANG Q. , MAYER M. , HOESCHELE I.
Published: March 2003

A granddaughter design containing five half‐sib families from German Holstein–Friesian cattle was subjected to QTL analysis starting from the hypothesis of the existence of more than one QTL on chromosome BTA 6 affecting milk yield, fat yield, protein yield and content of fat and protein. The marker map consisted of 16 microsatellite markers with marker heterozygosity varying from 0.44 to 0.94. Two statistical methods were used: least squares (LS) and residual maximum likelihood (REML) allowing for two QTL simultaneously. The test statistics were calculated in steps of one cM along the chromosome. Significant QTL at the chromosome‐wise 5% level according to the permutation test critical value were detected mainly in single families. The results were in conformance with the findings of several previous studies with approximate positions of putative QTL at 49 cM for milk yield, at 70 cM for fat and protein yield, and at 46 cM for protein content. Further QTL positions were suggested mostly for yield traits and protein content in the area of the casein gene cluster at 90…95 cM. The results of the two‐QTL model analyses when using LS led to family specific inferences of a second QTL for fat yield and content of protein and fat, partly supported by the epistasis model.
Analysis of pedigrees of Tux‐Zillertal, Carinthian Blond and Original Pinzgau cattle population in Austria
Authors: BAUMUNG R. , SÖLKNER J.
Published: March 2003

The most common goal of animal conservation programmes is to maintain genetic diversity. Various measures for genetic variability based on pedigree information can be used, but most of them are very sensitive to completeness of pedigree information. Different criteria based on probability of identity‐by‐descent (effective population size via increase in inbreeding Ne) or probability of gene origin (effective number of founders fe, ancestors fa and founder genomes Ng) were used to describe the genetic variability of three Austrian cattle breeds [Original Pinzgau (PI), Tux‐Zillertal (TZ), Carinthian Blond (CB)]. Reference populations for PI were defined by animals born between 1993 and 1997 and for TZ and CB by all living animals, irrespective of birth year. The numbers of animals in the reference populations were 9706, 471 and 230 for PI, TZ and CB, respectively. The average complete generation equivalent showed the different quality of pedigree information: 5.33 for PI, 2.52 for TZ and 1.73 for CB. The following Nes were calculated: 76 for PI and CB and 43 for TZ. For PI, TZ and CB a fe‐value of 65.4, 21.0 and 29.9, a fa‐value of 32.1, 14.2 and 29.0 and a Ng‐value of 19.5, 9.7 and 22.6, respectively, were calculated. In particular, the results for TZ demonstrate the urgent need for a well‐planned conservation programme.
Scaling of cytoplasmic and mitochondrial enzymes and proteins in skeletal muscle of a catfish
Authors: Tripathi G.
Published: March 2003

Introduction  The skeletal muscle has an effective chemical–mechanical transducer system to generate physical forces which needs a constant supply of Adenosine triphosphate (ATP). The ATP requirement may vary with the body size of organisms. Studies of the size‐dependent properties of animals have been mainly focused on aerobic processes and the underlying structures supporting them (S
chmidt‐N
ielsen 1984; E
wart et al. 1988; B
errioslopez et al. 1996). Some attempts have been made to correlate anaerobic process with body mass in fish (S
omero and C
hildress 1980, 1990). It has been reported that anaerobic metabolic processes exhibit different scaling patterns to those of aerobic processes (S
ullivan and S
omero 1980; H
eusner 1987; H
ochachka et al. 1987; S
omero and C
hildress 1990). The differences between aerobic and anaerobic capacities may be due to the differing roles of inter‐organ interactions in general metabolism. The scaling of metabolic enzymes has also been shown to be associated with the scaling of protein concentrations in fish (S
omero and C
hildress 1990). M
cM
ahan (1984) has remarked that the scaling of aerobic metabolism cannot be explained by engineering principles involving skeletal muscle strength. Thus in spite of some strong experimental supports, it has been too difficult to explain the intricacy of aerobic scaling (S
chmidt‐N
ielsen 1984; C
alder 1987; H
eusner 1987; S
omero and C
hildress 1990).W
eihs and W
ebb (1983) have argued that swimming speed should scale with body size to favour prey capture. Further, B
errioslopez et al. (1996) demonstrated the scaling of skeletal mass to body mass in fish. Since Clarias batrachus is a predatory teleost, the scaling of aerobic (MDH) and anaerobic (LDH) enzymes and proteins have been studied to test the existing hypotheses about the functional roles of metabolic scaling in fish.
Einfluß eines alimentären Calcium‐ und Zinkmangels auf die Aktivitäten Calmodulin‐regulierter Enzyme in verschiedenen Geweben der Ratte
Authors: Schmidmayer S. , Roth H. ‐P. , Kirchgessner M.
Published: March 2003

Einleitung

Zink übernimmt im tierischen und menschlichen Organismus viele biochemische Funktionen, so daß ein alimentärer Mangelzustand an diesem essentiellen Spurenelement zu massiven Stoffwechselstörungen und drastischen Mangelerscheinungen führt. Ebenso von essentieller Bedeutung für den Organismus ist aber auch das Mengenelement Calcium, das u.a. sowohl als Signalübermittler an der interzellulären Kommunikation als auch an der Aktivierung von Enzymen ganz wesentlich beteiligt sein kann. Die Regulierung und Aktivierung solcher Ca2+‐abhängiger Enzyme erfolgt meist über eine Bindung von Ca2+ an Calmodulin, ein niedermolekulares Protein mit vier Ca2+‐Bindungsstellen, das in allen Säugetierzellen vorkommt (C
heung 1980, 1982; B
rostrom and W
olff 1981; O
ldham 1982; W
alsh 1983; P
eersen et al. 1997) und für den Ablauf vieler biologischer Prozesse im Körper von großer Bedeutung ist. Zink hat aber ebenfalls einen Einfluß auf die Funktion von Calmodulin im Organismus (R
oth and K
irchgessner 1988, 1991a) und damit auch auf die Aktivierung dieser Enzyme (S
chmidmayer et al. 1999). In Zusammenhang mit diesen Fragestellungen wurden wachsende Ratten mit entsprechenden Diäten in einen alimentären Zink‐, Calcium bzw. in einen kombinierten Zink‐ und Calciummangel versetzt und dann die Aktivitäten von Calmodulin‐regulierten Enzymen wie der Ca–Mg–ATPase in der Erythrozytenmembran, der Phosphodiesterase und der Adenylat‐Cyclase in verschiedenen Geweben der Tiere bestimmt.
Influence of dietary carboxymethylcellulose on the apparent absorption of calcium, magnesium and phosphorus in rats
Authors: Vissia G. H. P. , Beynen A. C.
Published: March 2003

Introduction  Dietary pectin vs cellulose has been shown to enhance apparent magnesium absorption in rats (unpublished data). This observation supports that of V
ahouny et al. (1987), indicating that pectin feeding produced a more positive balance of magnesium in young, growing rats than did cellulose feeding. Pectin is a soluble, viscous and readily fermentable non‐starch polysaccharide, but is not digested by animal enzymes. Pectin feeding raises the viscosity of small intestinal digesta in rats (J
udd and T
ruswell 1985). The increase in magnesium absorption seen after pectin feeding could relate to its fermentation, which may lower the pH of the small intestinal digesta, which in turn raises the solubility of minerals, rendering them more available for absorption. Both dietary lactulose and lactose, which are not digestible but highly fermentable, lower the pH of small intestinal digesta and increase mineral absorption in rats (H
eijnen et al. 1993). The influence of viscosity per se on mineral absorption is unknown. In contrast to the above‐mentioned mechanism, the observed stimulatory effect of pectin feeding on magnesium absorption (unpublished data) could relate to viscosity of small intestinal contents. To provide clues as to this possibility, the model compound carboxymethylcellulose (CMC) may be used. This compound is not digested by animal enzymes, is non‐fermentable, but is highly viscous and has been shown to raise the viscosity of small intestinal contents in broiler chickens (S
mits et al. 1997). Thus we fed rats on diets with different levels of CMC to study the influence of digesta viscosity on apparent absorption of calcium, magnesium and phosphorus.
Energiebilanz bei energetischer Unterversorgung mit einer isokalorischen Kohlenhydrat‐oder Fettration am Sauenmodell
Authors: Müller . Von H. L. , KirchgeiNer M.
Published: March 2003

Einleitung

Eine dauerhafte Reduktion der Energiezufuhr wird bei Übergewicht aus trivialem biophysikalischem Grund zwangsläufig zur Gewichtsverminderung führen. Die Praktikabilität eines solchen Vorgehens in der Ernährung des Menschen erweist sich aber vielfach als schwierig. Das Interesse ist deshalb mehr darauf gerichtet, weniger durch bewuite Einschränkung der Energiezufuhr als vielmehr durch Änderung der Nahrungszusammensetzung einen günstigen Einflui auf die Energiebilanz zu erreichen. Ein viel diskutiertes Problem ist in diesem Zusammenhang die Relation des Kohlenhydrat‐ und Fettanteils in der Nahrung. Nach mehreren Befunden am Menschen wird den Kohlenhydraten eine regulative Funktion zugeschrieben, wobei die Kohlenhydratbilanz über Oxidation dieses Nährstoffes ausgeglichen wird. Demgegenüber wird die Fettbilanz nicht ausgeglichen, so dai überschüssige Fettzufuhr zu einem entsprechenden Ansatz von Körperenergie führt (F latt 1993, 1995; J&
eacute;
quier 1993). In exakten Energiebilanzversuchen mit Sauen wurde jedoch gefunden, dai Kohlenhydrate und Fette im Erhaltungsbereich als gleichwertige Energielieferanten (ATP‐Effizienz) zu sehen sind. Im Überschuibereich lieferten Fette einen höheren Energieansatz als Kohlenhydrate, wobei sich die Differenz durch die unterschiedlichen Energiekosten für die Fettbildung erklären liei (sog. obligatorische Thermogenese). Eine eigentliche regulative Funktion (fakultative Thermogenese) der Kohlenhydrat‐Fett‐Relation auf die Energiebilanz konnte nicht festgestellt werden (KIRCHGEiNER und M&
uuml;
ller 1998; M&
uuml;
ller und KIRCHGEiNER 1998). Nach diesen Ergebnissen sollte man erwarten, daß eine kohlenhydratreiche oder fettreiche Reduktionsdiät sich ebenfalls nicht unterschiedlich auf die Gewichtsreduktion auswirkt. Im vorliegenden Versuch wurde dies bei streng kontrollierter kalorischer Unterversorgung an Sauen überprüft.
Nutrient oxidation and lipogenesis in hens
Authors: Chwalibog A. , Thorbek G.
Published: March 2003

Introduction  Indirect calorimetry based on measurements of gas exchange has been used successfully during the last century in order to estimate energetic values of feedstuffs and animals’ requirement for nutrients and energy. Recently, measurements of gas exchange have been used to calculate nutrient oxidation and lipogenesis in the intact body of man (T
horbek et al. 1994), pigs (C
hwalibog et al. 1992; C
hwalibog and T
horbek 1995), calves (C
hwalibog et al. 1996; C
hwalibog et al. 1997a), mink (T
auson et al. 1997) and rats (C
hwalibog et al. 1998).

In the present paper a similar approach has been used to quantify nutrient metabolism in laying hens in accordance with a calculation method first proposed by C hwalibog et al. (1992) and later modified as outlined in Fig. 1.

According to this biological model digested protein (DP) which is equal to PROT – group is utilized for retention in eggs (OP), ovary and body (OBP), whereas deaminated amino acids are oxidized (OXP) with concomitant excretion of energy with nitrogenous substances in urine (UEN) and contribution of energy (GLUC) to carbohydrate metabolism. Digested carbohydrate (DCHO) together with GLUC constitute the CHO – group, which is retained in eggs (OCHO), oxidized (OXCHO) and used for lipogenesis (LIPO). Digested fat (DFAT) and lipids from lipogenesis constitute the FAT – group, which is incorporated into eggs (OF), ovary + body (OBF) and oxidized (OXF). Both CHO and FAT metabolism contribute with energy containing products excreted with urine (UEN‐free). The energy from OXP, OXCHO and OXF make up the total heat production (HE). The validity of the method will be discussed later.

The aim of this study was to demonstrate how data from gas exchange measurements in combination with nitrogen and energy balances can be applied in order to calculate nutrient oxidation and the quantities of substrates used for retention and lipogenesis processes, and furthermore, to elucidate differences in nutrient oxidation and lipogenesis in relation to different housing conditions and genotypes of laying hens.
Fatty acid composition of tissue lipids of growing geese fed cholesterol and cholic acid
Authors: Eder K.
Published: March 2003

In laboratory animals, dietary cholesterol has been shown to cause increased levels of lipids in plasma and liver, and additionally markedly raises liver weights (Lee and Ho 1975; Huang et al. 1984; Stangl et al. 1994). In poultry, similar studies dealing with the effects of cholesterol are lacking. An effect of cholesterol on liver weights could be of particular interest in geese since the production of fatty livers (‘Foie gras’) by force‐feeding techniques is common in some countries. Therefore, a previous study (Eder 1999) was concerned with the effects of feeding cholesterol on concentrations of various lipids in liver, plasma and muscle. This study demonstrated that dietary cholesterol has profound effects on lipid concentrations in liver, plasma and even in the muscle of geese which were additionally amplified by feeding cholic acid. This study was performed to investigate whether an accumulation of cholesterol in tissues also affects the metabolism of fatty acids. This question was of particular interest because it is known that both, cholesterol and fatty acids are constituents of membranes influencing important membrane properties such as fluidity, permeability or the activity of membrane‐bound enzymes (Stubbs and Smith 1984). In order to clarify that question, the fatty acid composition was analysed in various tissues of geese that had been fed diets with cholesterol and/or cholic acid.
Prediction studies on number of teratocytes and eggs of Microplitis rufiventris Kok. (Hym., Braconidae) parasitoid in superparasitized host larvae
Authors: Khafagi W. E. , Hegazi E. M. , Showail S.
Published: March 2003

1 Introduction

Microplitis rufiventris Kok. (Hym., Braconidae) is an internal solitary parasitoid of many noctuid caterpillars including the cotton leafworm Spodoptera littoralis (Boisd.) (
Kokujev 1914;
Hammad et al. 1965
;
Gerling 1969), the lesser cotton worm S. exigua Hbn. (
Meier 1929;
Thompson 1946;
El‐Minshawy 1963); S. latebrosa Lederer (
Hammad et al. 1965
) and American bollworm Heliothis armigera Hbn. (
Meier 1929;
Ibrahim & Tawfik 1975). When the egg of M. rufiventris hatches in its host, S. littoralis, spherical cells from the serosa that envelope the parasitoid embryo are released into the host’s haemolymph. Approximately 400 cells are liberated from an egg of the parasitoid. These cells increase in size, reaching a maximum average diameter of 137 μm at the completion of parasitoid development (
Khafagi 1997). These cells are most frequently called ‘teratocytes’ (
— 1968
, 1971;
Vinson 1970). It is reported that the presence of large numbers of the teratocytes is indicative of superparasitism but their number does not give an indication to the exact number of parasitoid eggs from which the cells have been derived (
—, — Khafagi et al. 1998
) . Therefore, it was of interest to initiate prediction studies on egg and teratocyte numbers in superparasitized host larvae.
Radiation protection of microbial pesticides
Authors: Ragaei M.
Published: March 2003

Natural sunlight, especially the ultraviolet (UV) portion of the spectrum (UV‐B, UV‐A), is responsible for inactivation of the microbial insecticides. Starch or flour encapsulation of microbial pesticides including bacteria, viruses, fungi, nematodes and protozoa in addition to antioxidants, oxidative enzymes or radical scavengers may also play a critical role in the protection of insect pathogens during solar irradiation. Some chemicals, with particular emphasis upon dyes and optical brighteners are used asUV screens to protect insect pathogens. Research in the area of UV screens will be emphasized from both basic and applied aspects.
Causes of regional and yearly variation in pea aphid numbers in eastern England
Authors: McVean R. I. K. , Dixon A. F. G. , Harrington R.
Published: March 2003

Regional variation in the number of pea aphids caught in the suction traps of the Rothamsted Insect Survey (RIS) was associated with the proportion of each region under pea crops. The degree of infestation of crops was similar in areas of high and low pea production as the mean annual abundance of aphids per hectare of crop remained constant. Yearly variation in abundance was loosely associated with temperature from January to July. Cold weather in January and February resulted in large numbers of aphids. Warm weather in February led to early colonization, and emigration from, pea crops as well as making early sowing of the crop more likely. A forecast of the time of first appearance of Acyrthosiphon pisum in the aerial plankton can be made, based on February temperature. Populations of A. pisum on peas appear to be regulated by alata production. High densities of aphids resulted in almost all the nymphs developing into alatae which, on reaching maturity, emigrated, causing populations on the crop to decline. This explains population crashes of the pea aphid observed at early growth stages of the crop, on vining and combining peas. Late sowing of peas, a probable effect of cold winters, results in higher aphid densities at flowering. The probable explanation for this is that late‐sown crops are colonized at an earlier growth stage, so that the aphid population has a longer period of time in which to develop.
Artificial overwintering chambers for green lacewings: results of international trials and implications for pest control
Authors: McEwen P. K. , Åkerberg C. , Bozsik A. , James C. J. , Eccleston L. , Lenartsson M. , Rossiter P. , Tuovinen T.
Published: March 2003

Lacewing overwintering chambers placed correctly in the field may be colonized by large numbers of adult common green lacewings (Chrysoperla carnea). This paper reports field results collected over 2 years from chambers placed in a number of European locations. Considerable variation was found in the success rates of the chambers from different areas and some suggestions are made as to why this might be. An experiment was conducted to investigate the potential use of overwintered lacewings in pest control. This attempt was not successful and possible reasons why are discussed.
Effects of prey density and spatial distribution on prey consumption of the adult predatory ladybird beetle
Authors: Yasuda H. , Ishikawa H.
Published: March 2003

The effects of prey density and spatial distribution on prey consumption of the adult predatory ladybird, Harmonia axyridis, were investigated by using a 2 × 2 factorial design in large scale cages. Prey density influenced prey consumption of the ladybirds, and the frequency with which predation occurred was quite different between the prey distributions. The ladybirds consumed a relatively constant and small number of aphids when the prey were uniformly distributed, whereas the number of prey consumed per day when predation occurred was large and much more variable when the prey were contagiously distributed. At high prey density, the number of prey consumed was highest during the first day of the experiment; thereafter, only 10–20 aphids were consumed during the following 3 days. However, these patterns of prey consumption were not observed at low prey density. The percentage of aphids that remained on the host plants when the experiments were terminated was higher at low prey density than at high prey density, suggesting that predator foraging efficiency at low prey density was lower than at high prey density. Ladybirds foraging for high prey density were more frequently observed on the plants with aphids than ladybirds foraging for low prey density. Prey distribution also influenced the frequency of residence of ladybirds on the plants. The different predation patterns observed in the two spatial distributions, in which prey consumption was much more variable for the contagious distribution, might be explained by the difference in prey encounter rate of the predator between the distributions. This study indicated that the ladybirds had limited ability to search out prey over large spatial scales.