bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plant density effects on growth, yield, leaf area index and light transmission on intercropped maize and Vigna unguiculata (L.) Walp. in Nigeria
Authors: Fawusi M. O. A. , Wanki S. B. C. , Nangju D. 
Published: March 2009

SUMMARYIn field experiments at the International Institute of Tropical Agriculture in Nigeria, two cow-pea cultivars, TVU-1209 and FARV-13 and a composite maize cultivar were intercropped at plant densities of 10000, 20000, 30000 and 40000 plants/ha in a split-plot design. There were four replications of each density. Results showed that increasing cow-pea plant density increased the number of days to flowering but decreased the numbers of branches and of leaves per plant in both monoculture and mixture. Different varietal responses to plant density were observed for other growth measurements. While TVU-1209 yielded the highest dry matter at 20000 plants/ha in monoculture and mixture, FARV-13 did so at 40000 plants/ha in monoculture and at 20000 in mixture. Some yield components decreased while others were unaffected by increasing plant density. Similar response pattern was observed for maize. Both leaf area index and light interception were greater in FARV-13 than in TVU-1209.
Assessing potato seedling progenies for resistance to the white potato cyst-nematode
Authors: Phillips M. S. , Dale M. F. B. 
Published: March 2009

SUMMARYA bulk seedling test is described which can be applied shortly after completion of a crossing programme. The test assesses resistance to G. pallida in progeny derived from crossing programmes involving S. luberosum, S. vernei and S. tuberosum spp. andigena. It provides good estimates of both the mean level of resistance within progenies and the breeding value of the parents. The test was applied to a crossing schedule involving a half-diallel and a North Carolina 2 design utilizing a range of material. The results and their implications are discussed.
Effects of dietary N on lipids of rumen digesta, plasma, liver, muscle and perirenal fat in sheep
Authors: Gerson T. , John A. , Shelton I. D. , Sinclair B. R. 
Published: March 2009

SUMMARYTwo-year-old Romney wethers were fed diets with (a) varying proportions of N (0·5, 1·1, 1·4 and 3·4%) while on similar digestible organic matter (DOM) intake, and (b) the same proportions of N with different DOM intake.The composition of rumen volatile and unesterified fatty acids, as well as of lipids and fatty acids of plasma, liver, muscle and perirenal fat, was determined.When the proportions of dietary N were varied the findings were as follows: in the rumenahigh level of propionate (37%) was found on the 1·4% N diet, unsaturated fatty acids constituted between 20 and 30% of rumen unesterified fatty acids with diets containing 0·5 and 3·4% N, while sheep on 1·1 and 1·4% N diets had 70·80% unsaturated fatty acids. In plasma and tissues other than the liver there was a greater proportion of unsaturated fatty acids in sheep fed the 1·4% N diet. Total liver lipids were highest on the 0·5 and 3·4% N diets. Perirenal fat was highest on the 0·5% N diet.With the exception of unesterified cholesterol, tissue and plasma cholesterol concentrations decreased with increasing dietary N content.Increased DOM intake while the proportion of dietary N was kept constant caused few changes in lipid and fatty acid composition of rumen, plasma and tissues.
Low temperature growth in a controlled environment of Lolium perenne L. ecotypes from northern latitudes
Authors: Ollerenshaw J. H. , Baker R. H. 
Published: March 2009

SUMMARYNineteen ecotypes from northern Britain and selected genotypes of a cultivar of L. perenne were assessed in controlled environments for shoot growth at low temperature and irradiance and also short daylengths. The ecotypes were collected from a range of altitudes at sites experiencing estimated mean monthly temperatures in the coldest month between -0·1 and + 4·2 °C.A clinal relationship between low temperature growth and the winter temperature at the place of origin of the ecotypes could not be found in these experiments. Low temperature growth was not generally associated with altitude of origin of the plants, but in this study some of the plants collected from mid-altitude were exceptional in leaf growth produced at 5 °C. Types of L. perenne which extended leaves quickly also produced heavier shoot weights than other types less able to show rapid leaf extension at low temperature. The exceptional ecotypes may provide useful basic plant material for breeding cultivars of L. perenne to grow at low temperatures, and irradiances and short daylengths. Several possible explanations are discussed for the differences in shoot growth found between L. perenne ecotypes at low temperature.
Effects of short-term waterlogging on growth and yield of cowpea (Vigna unguiculata)
Authors: Minchin F. R. , Summerfield R. J. , Eaglesham A. R. J. , Stewart Katrine A. 
Published: March 2009

SummaryWhen cowpea plants were grown in large pots under simulated tropical conditions, and were dependent on either symbiotic fixation or inorganic N for their total nitrogen requirements, short periods of waterlogging had adverse effects on vegetative growth and seed production. The effects of waterlogging were more acute as plants experienced stress at progressively earlier stages of development. In plants depending either on biologically fixed N or inorganic N, waterlogging before flowering reduced vegetative growth by about 50%. Although some compensation in vegetative growth occurred during the reproductive development of nodulated plants, seed yields in both cases were still 48% less than in unstressed plants. Depending on the stage of plant development, treatment effects were mediated largely through changes in branch, peduncle and flower production and/or abortion, which contributed directly to variations in the number of pods retained to maturity. Inorganic nitrogen stimulated vegetative growth but did not significantly improve seed yield compared with effectively nodulated plants.
The relative resistance to escape of leaf and stem particles from the rumen of cattle and sheep
Authors: Poppi D. P. , Hendricksen R. E. , Minson D. J. 
Published: March 2009

SUMMARYIn a study of the effect of animal species on the threshold particle size leaving the rumen, two grasses cut at two stages of growth and one mature legume were separated into leaf and stem fractions and fed to cattle and sheep. Samples of rumen digesta and faeces were used to determine the validity of using a 1·18 mm porosity screen to separate the rumen particles into large and small pools when studying escape of particles from the rumen. Samples of rumen digesta and faeces were collected for the determination of particle size by wet sieving and the calculation of resistance of particles to passage from the rumen relative to small particles retained on a 0·15 mm sieve.Particles < 1·18 mm but > 0·5 mm had a mean relative resistance to passage of 2·0 and 2·6 for cattle and sheep respectively, compared with resistance values of between 10·9 and 31·2 for particles between 1·18 and 2·36 mm. It is suggested that there is no justification for using different threshold particle sizes for sheep and cattle and that a 1·18 mm sieve may be used to divide the rumen contents of both cattle and sheep into two pools of particles with high and low relative resistance to passage from the rumen.
Intrinsic antibiotic resistance in chickpea (Cicer arietinum) rhizobia
Authors: Garg F. C. , Beri N. , Tauro P. 
Published: March 2009

SUMMARYMore than 200 wild type isolates of chickpea (C. arietinum) rhizobia were screened for their drug resistance. Only 15 were found to be resistant to one or more antibiotics at a concentration of 5 μg/ml (units/ml). When tested for multiple drug resistance, some were found to be resistant to more than one antibiotic. In competition studies, rhizobia resistant to streptomycin were found to be more competitive than antibioticsensitive strains, while those resistant to penicillin could not compete even with antibiotic-sensitive strains.
Boran cattle maintained by chemoprophylaxis under trypanosomiasis risk
Authors: Trail J. C. M. , Murray M. , Sones K. , Jibbo J. M. C. , Durkin J. , Light D. 
Published: March 2009

SUMMARYReproductive performance, mortality, growth, and culling and replacement rates based on 20000 calving records were evaluated for grade Boran beef cattle maintained with trypanocidal drugs in an area of high trypanosomiasis risk in Tanzania. Under ranching conditions, over a 10-year period in this area of highGlossina morsitans morsitans, G. pallidipesandG. brevipalpischallenge, a calving interval of 15·9 months, pre-weaning mortality of 8%, annual cow mortality of 5·8% and 8-month weaning weight of 133·5 kg resulted in a herd productivity of 96 kg of weaner calf per cow per year. The proportion of heifers required as replacements (45%) and the generation interval (6·9 years) indicated scope for implementation of selection programmes on growth traits. The level of productivity achieved compared favourably with major data sets recently analysed from pure Boran cattle under trypanosomiasis-free ranching conditions in Kenya, and from trypanotolerant N'Dama cattle in West Africa. These results indicate the possibility of improving livestock production in tsetse-infested areas by the rational use of chemoprophylaxis as an integral part of management.Year, season, cow age, calf sex and location on ranch had significant effects on practically all the traits of calving interval, pre-weaning mortality and growth, and cow productivity. Superior performance where bush clearance and tsetse fly control had taken place suggests that economic evaluation of these interventions should be attempted. The season of calving had a major effect on productivity. Cows of 5–8 years of age were the most productive, as were animals producing male calves, features well recognized in beef cattle production.An average of 4·4 treatments with Samorin, a prophylactic, and 0·6 treatments with Berenil, a therapeutic, were required per year. The number of treatments varied from year to year and by area, being greater in the south of the ranch where the tsetse challenge was considered higher. However, the age and season of calving had little effect on the number of treatments required. Despite such extensive use of trypanocidal drugs, there was no indication that drug resistance had developed or evidence that repeated inoculation of Samorin had affected productivity.Grading-up of small East African Zebu cattle to Boran over an 8-year period allowed annual comparison of birth weights, pre-weaning growth and weaning weights of two groups of calves, one having a higher level of Boran genes (varying from 12 to 6% higher annually) than the other. Those with the higher level of Boran genes performed better by 3·3% for all attributes studied, but as the percentage difference in Boran genes decreased, so did this difference. In an environment improved through bush clearance and tsetse fly control, the calves with higher levels of Boran genes were superior, but this superiority was not expressed in the unimproved environment.
On exogenous chemical imposition of ephemeral dormancy in cereal seed
Authors: Leshem Y. Y. 
Published: March 2009

SummaryChemical imposition of water leachable germination inhibition was attempted as a means of overcoming wheat seedling wilting after insufficient rainfall. Effective inhibition in aqueous solutions was imposed by abscisic acid, coumarin and by two ethylene releasing preparations, Ethrel and Alsol. Germination inhibition caused by the latter two compounds was found to be associated with effects of the carriers, other than pH, and was not a result of ethylene gas liberation. As evidenced by tetrazolium staining the dormant seed possessed respiratory activity, and imposed germination inhibition, even to the extent of 75%, was not lethal. Rainfall simulation effected by 30 h H2O leaching with a 200 mm precipitation equivalent was ineffective for reversal of germination inhibition caused by abscisic acid and Alsol, limitedly effective in the case of Ethrel, while the coumarin-induced inhibition was relieved to a greater extent.
A study of some wool traits in two coarse wool breeds and their reciprocal crosses
Authors: Guirgis R. A. , Kazzal N. T. , Haddadine M. S. , Abdallah R. K. 
Published: March 2009

SummaryIn a study of two coarse wool breeds (Awassi and Karadi) and their reciprocal crosses, data were obtained on the mean fibre length, mean fibre diameter, fibre type ratio, medullation and on the effect of some environmental factors on these traits. Reciprocal crosses showed intermediate values, in growth rate of fibres, percentages of fibre types and medullation, between those of the parental breeds. Sex exhibited a significant effect at weaning only, on fibre length. Heterosis in fibre length, at the two ages, was small and negative. Maternal influence on fibre length was small and not significant. Fibre length in Karadi sheep showed the highest frequency of bimodal distribution whereas Awassi showed the lowest. Awassi × Karadi was closer to Karadi and Karadi × Awassi had greater affinity to Awassi in the frequency of samples showing bimodal distribution.Reciprocal crosses had larger diameter, at weaning, than those of the parental breeds. At 1 year of age they assumed an intermediate position between the pure bred parents.At weaning, the two reciprocal crosses showed a highly significant heterosis in fibre diameter; its value decreased with advancing age and it showed no significant effect at 1 year of age.Maternal influence on fibre diameter was very small and not significant.Karadi × Awassi and Karadi samples had the highest percentage of samples showing bimodal distribution of fibre diameter.Samples with bimodal distribution of both length and diameter, indicating two coats, had the highest frequency in Karadi followed by Karadi × Awassi; Awassi showed the lowest value.Percentages of fine, coarse and kemp fibres were significantly affected by breed and age of dam. Type of birth showed a significant effect only on percentage of coarse fibres.Karadi wool might be more suitable for carpet manufacturing. It excelled the other groups in the bimodal distribution of both length and diameter as well as in medullation. Cross-breeding increased the bimodality of fibre distribution.
Fruit and seed development in mung beans (Phaseolus aureusRoxb.)
Authors: Savithri K. S. , Ganapathy P. S. , Sinha S. K. 
Published: March 2009

SummaryA study of fruit set at different nodes was made in mung beans,Phaseolus aureusRoxb., under field conditions. Flowering commenced on the fourth node from the base and the percentage fruit set showed a gradual decrease from the fifth node upwards. Yield analysis was carried out for each of the fruiting nodes. When the leaf and inflorescences at a node are taken as a functional unit it is seen that there was a decrease in the ratio of leaf area to fruit and seed weights from the base of the plant upwards indicating that at the upper nodes particularly, some other plant parts also contribute to the photosynthate pool of the developing seeds.A quantitative study of the dry matter, proteins and starch in the fruit wall and seeds of fruits at different stages of development was made. It showed that the rapid increase in dry matter, proteins and starch in the seeds at the later stages of development is compensated, in part, by a decrease of these components in the fruit wall. Histochemical studies of the fruit wall further supported these observations. This indicated the contribution of substrates by the fruit wall to the developing seeds.
Studies on nitrogen fixation by antibiotic-resistant mutants ofAzospirillum brasilenseand their interaction with cheena (Panicum miliaceumL.) genotypes in calcareous soil
Authors: Rai R. 
Published: March 2009

SUMMARYAzospirillum brasilense was treated with nitrosoguanidine and five antibiotic-resistant mutant strains isolated. Variations in growth, N2-fixation, ultraviolet-dark survival and level of antibiotic resistance were found between the mutant strains. Mutant strains STR 112 and KR 2051 showed maximum nitrogenase activity, glutamine synthetase activity and hydrogenase activity (H2uptake) at 32 °C and 40 °C respectively. Inoculation of cheena genotypes withA. brasilenseand its mutants led to significant increase in associative nitrogen fixation, dry weight of roots and grain yield compared with the uninoculated control, with significant strains × genotypes interactions in calcareous soil. It was also noted that under laboratory conditionsAzospirilluminoculation may have produced its response by hormonal means and/or associative N2-fixation.
In vivocolonization of grass cell walls by rumen micro-organisms
Authors: Elliott R. , Norton B. W. , Ford C. W. 
Published: March 2009

SUMMARYCell wall preparations from stems of four mature grass species, pangola grass, setaria, sugar cane and barley straw were incubated in nylon bags in sheep fitted with rumen cannulae and fed chopped pangola grass at hourly intervals. After varying incubation times D.M. loss, and incorporation of35S into microbial cystine on the fibres, were measured. Pangola and barley straw were digested to a much greater extent (ca.48 and 44%) than sugar cane and setaria (ca.29 and 23% respectively) and digestion was still continuing after 60 h. With the exception of setaria, microbial colonization of the cell wall preparations peaked after 24 h incubation and then declined. In setaria only a small amount of [35S]cystine was measured, the level of which did not change appreciably after 18 h.After 24 h incubation, microbial colonization on pangola fibre was about three times that on barley straw and sugar cane. Only on pangola fibre did cystine accumulation, and its subsequent rapid decline, coincide with the development and detachment of fungal sporangia. There was no relationship between the extent of microbial colonization and D.M. loss from the fibres. Sulphur concentrations, both in the plant fibres and rumen fluid, could not explain the greater fungal growth on the pangola cell walls in preference to the other species.
The effect of inclusion of mineral salts in the diet on dilution rate, the pattern of rumen fermentation and the composition of the rumen microflora
Authors: Thomson D. J. , Beever D. E. , Latham M. J. , Sharpe M. E. , Terry R. A. 
Published: March 2009

SummaryThe mixed buffer salts of artificial saliva were incorporated at three rates: 0 (diet 1), 5·7 (diet 2) and 11·4% (diet 3) (w/w) in pelleted diets prepared from60% ground flaked maize and 40% dried ground grass. The control and mineral-supplemented diets were fed to sheep hourly (Expt 1) or twice daily (Expt 2).When the sheep were fed hourly or twice daily the pattern of fermentation in the rumen was altered from a predominantly propionate to mainly acetate fermentation. Dilution rate in the rumen increased from 0·036 to 0·053 to 0·064 when diets 1, 2 and 3 were fed hourly, and dilution rate was negatively related to the molar proportion of propionic acid (P< 0·05) and positively related (P< 0·05) to the molar proportion of acetic acid in rumen fluid, but these relationships were not apparent in Expt 2.Nitrogen retention was higher for lambs fed diet 2 than for those fed diets 1 and 3 (P< 0·05) in Expt 1.In sheep fed hourly, selenomonads and bacteroides were the predominant rumen bacteria associated with the control diet but the inclusion of mineral salts resulted in the bacteroides being replaced by large number of chain-forming cocci. Numbers of protozoa were variable. The relationship of these changes to the fermentation pattern is discussed. In sheep fed twice daily there was much variation between animals.
The interactions of water and fertilizer nitrogen in effects on growth pattern and yield of potatoes
Authors: Clutterbuck B. J. , Simpson K. 
Published: March 2009

SummaryThree field experiments in 2 years were made in S.E. Scotland to investigate the effect of water (normal rainfall or irrigation to maintain soil moisture tension between pF 2·0 and 2·5) on the response of the potato crop to nitrogen fertilizer (0, 100, 200 or 300 kg N/ha).Final tuber yield was closely related to leaf area duration. Addition of water reduced the delay in early haulm growth resulting from fertilizer nitrogen application. The beneficial effect of reducing moisture tension could not be related to water per se, nitrate, ammonium or conductivity levels in the fertilizer band or nitrogen uptake. Accumulation of nitrate in the roots and stems + petioles early in the season indicated that the rate of protein synthesis was reduced at high soil moisture tension in the presence of fertilizer nitrogen.In a long growing season (1971, 153 days) there was a significant response of tuber yield to nitrogen, with an increase in yield even at the highest rate tested (300 kg N/ha) and irrigation enhanced this response.In a normal season (1970, ca.130 days) there was a significant irrigation x nitrogen interaction on tuber yield. Irrigation increased the optimum rate of nitrogen from 100 to 200 kg N/ha in one experiment and from nil to 200 kg N/ha in another.Addition of water increased the number of tubers at harvest but the effect of nitrogen was less consistent. Yield increases resulting from application of nitrogen or reduction in soil moisture tension were mainly due to increases in the proportion of large tubers.
Studies on genotype × spacing interactions for herbage yield, using a modified diallel analysis
Authors: Sedcole J. R. , Clements R. J. 
Published: March 2009

SummaryForty-four full-sib families from a diallel cross between 10 Lolium ((multiflorum × perenne) × perenne) clones were planted in the autumn at 0·6 × 0·6 m and 0·l × 0·l m spacings. Fresh weight of individual plants was measured on three occasions during the following spring and summer. The analysis of the diallel cross was extended to account for combining ability × spacing interactions, and to estimate between-spacing combining ability correlations and their sampling errors.Family × spacing interactions became increasingly significant at successive harvests and always contributed substantially to the total phenotypic variance. Much of the family × spacing variance was due to the general combining ability (GCA) × spacing component. Despite these large and significant interactions, the correlation between GCA values at the two spacings was high and positive at each harvest, so that selection for yield at wide spacing should lead to a correlated increase in yield at close spacing. Although the experiment was of relatively short duration, the results suggest that recent criticism of the conventional technique of selection among widely spaced plants in pasture plant breeding programmes may not have been entirely justified.