bluuebunny/crossref_metadata_2025_split huggingface dataset:
Restriction Fragment Length Polymorphisms (RFLPS) and Crop Improvement
Authors: Young Nevin Dale 
Published: October 2008

SUMMARYRestriction fragment length polymorphisms (RFLPs) are genetic markers based on cloned molecules of DNA. Using RFLPs, scientists can construct high density genetic linkage maps and locate economically important genes. Once a gene for a valuable trait has been mapped with RFLPs, desirable genotypes can be selected using RFLPs rather than scoring for the trait itself. This is important when a trait is recessive, difficult to score, or obscured by other characters. RFLPs are particularly valuable in mapping genes controlling complex polygenic characters, including those fundamental to crop improvement. The first RFLP maps were developed in crop species primarily important in temperate countries. Now RFLP maps for major tropical and sub-tropical crop species are also being developed.
Response ofBradyrhizobium-Inoculated Soyabean and Lablab Bean to Inoculation With Vesicular-Arbuscular Mycorrhizae
Authors: Mahdi A. A. , Atabani I. M. A. 
Published: October 2008

SUMMARYPot and field investigations were conducted to study the effects of vesicular-arbuscular mycorrhizal (VAM) inoculation and triple superphosphate fertilization on nodulation, dry matter yield and tissue nitrogen and phosphorus contents ofBradyrhizobium-inoculated soya-bean and lablab bean in the Sudan.Inoculation of both crops with the VAM fungusGlomus mosseaein clay and sandy soils in pots increased nodulation, dry matter yield and tissue nitrogen and phosphorus contents more than triple superphosphate fertilizer, but even greater responses were obtained fromG. mosseaecombined with fertilizer. Crop responses in the two soils were similar, despite the large differences in soil physico-chemical properties.In the field, inoculation of both crops with any of four VAM fungi enhanced nodulation, dry matter yield and plant nitrogen and phosphorus contents more than did triple superphosphate.Gigaspora margaritaandGlomus mosseaewere superior toGigaspora calosporaandAcaulosporaspecies and resulted in more extensive root infection, especially in soyabean.
Competitive Effects of a Short Duration, Bush Type Cowpea When Intercropped With Cotton in Zimbabwe
Authors: Natarajan M. , Naik D. M. 
Published: October 2008

SUMMARYCowpea is an important supplement to the staple diet of maize in Zimbabwe, but its productivity is poor beacuse of pest infestations. This paper reports the results of experiments conducted over two crop seasons on the feasibility of producing a grain crop of cowpea intercropped with cotton to take advantage of cotton's slow initial growth and of drift from insecticides applied to it. Intercropping reduced the yield of cotton by between 11.5 and 73% depending on the type of season and the treatments applied, but the reduction was compensated by the yield of cowpea. The yield reduction was greater in the drier first season and with simultaneous planting of the two crops. Cowpea consistently performed better as an intercrop than as a sole crop, mainly because of the protection it received from the insecticides applied to the cotton.
Correction of Acid Infertility in Rwandan Oxisols with Lime from an Indigenous Source for Sustainable Cropping
Authors: Yamoah Charles F. , Burleigh J. R. , Eylands V. J. 
Published: October 2008

SUMMARYSustainable crop production on Rwandan oxisols is limited by widespread soil acidity caused by high levels of exchangeable aluminium. This study was designed to test the effectiveness of an indigenous lime material in counteracting the acidity and enhancing crop yields. Lime application significantly raised pH, exchangeable calcium and effective cation exchange capacity, and reduced exchangeable aluminium and total acidity. Calcium was directly proportional to effective cation exchange capacity (r = 0.962**) and was inversely related to aluminium (r = −0.955**). Consequently, yields of wheat, beans and potatoes, which served as test crops, were significantly increased by liming. Lime at high rates (4–8 t ha−1) had a longer residual effect than at low rates (less than 2 t ha−1), suggesting frequent applications are needed when low lime rates are used. Simple regression analysis showed an increase in pH of 0.154 units and a decrease in exchangeable aluminium of 0.385 meq 100 g−1 for a tonne of lime applied.
Forage Production for Smallholder Farmers in a Rainfed Millet Cropping System in Central Mali
Authors: Bartholomew P. W. , Ly R. , Kone D. , Traore S. F. , Sissoko K. 
Published: October 2008

SUMMARYA shortage of available labour early in the growing season, when effort is directed to the weeding ofcereal crops, appeared to be a primary constraint to increased forage cropping by smallholder farmers in the semi-arid zone of central Mali. In experiments with millet, the labour requirement for weeding was reduced by an average of 45% when the crop was weeded at two rather than four weeks after emergence. A combination of weeding by hand and by ox-drawn plough or harrow only slightly increased labour productivity compared with hand weeding alone. Both lablab and cowpea produced good yields of forage when sown in mid July, but average yield declined by 71 kg ha−l for each day's delay in sowing between mid July and mid-August. Green gram was also productive over a two month growing period and appeared to have potential as a late-sown forage crop.
Vesicular-Arbuscular Mycorrhiza and Phosphorus Uptake of Chickpea Grown in Northern Syria
Authors: Weber Edwin , George Eckhard , Beck Douglas P. , Saxena Mohan C. , Marschner Horst 
Published: October 2008

SUMMARYInoculation with vesicular-arbuscular mycorrhizal fungi (VAMF) improved growth of chick-pea (Cicer arielinumL.) and doubled phosphorus (P) uptake at low and intermediate levels of P fertilization in a pot experiment on sterilized low-P calcareous soil. In field experiments at Tel Hadya, northern Syria, growth, shoot P concentration and seed yield of spring-sown chickpea remained unaffected by inoculation with VAMF or by P fertilization. The mycorrhizal infection of chickpea was high (approximately 75% of root length mycorrhizal at the flowering stage) irrespective of inoculation with VAMF or P fertilization and may ensure efficient P uptake under field conditions.
Small Farmer Mechanization in the Santa Cruz Colonization Zone: a Failure of Farming Systems Diagnosis?
Authors: Thiele Graham 
Published: October 2008

SUMMARYThis paper uses survey results to show how one group of small scale farmers in Santa Cruz, Bolivia, were able to mechanize annual cropping despite a farming systems diagnosis which indicated that this was not a viable development path. It attempts to identify the underlying causes of farmer success and diagnosis failure.
Prospects for Improving Mediterranean Grasslands in Lebanon through Seeding, Fertilization and Protection from Grazing
Authors: Osman Ahmed E. , Cocks Phil S. 
Published: October 2008

SUMMARYGrassland productivity was studied for four years near Terbol, Lebanon. In the first year pasture availability and plant numbers were monitored along transects, and in the following three years the effects of sowing four Mediterranean annual legumes (three cultivars of subterranean clover and a local ecotype of Medicago rigidula) and top-dressing with super-phosphate were studied. The results indicated that natural grasslands were dominated by annual grasses (Aegilops, Hordeum, Bromur, Lolium and Poa). Legume density was low, which resulted in poor legume productivity, especially in winter. Exotic legumes only resulted in a slight improvement in pasture productivity even when phosphate fertilizer was added. However, partial protection from grazing (for one or two months in late winter and spring) more than doubled the number of legume seeds in the seed bank compared with full protection and open grazing. The build up of seeds in the soil is an essential step towards the improvement of productivity in these degraded pastures, which form a large part of the land surface in Lebanon and on which small ruminant production largely depends.
The Importance of Liming Acid Soils of the Sahel Regions of Africa to Sustain High Crop Productivity—a Case Study from the Republic of Cameroon
Authors: Prabhakaran Nair K. P. , Ngachie V. , Nzetchoung F. 
Published: October 2008

SUMMARYGroundnut (Arachis hypogaea) has very great economic importance in Cameroon. In pot experiments, groundnut yields on highly acidified but limed soil were 50% greater than those on unlimed soil. These results demonstrate that severely acidified soils of the western highlands of Cameroon should be limed at moderate rates to sustain crop productivity.
Data Analysis in Agricultural Experimentation. III. Multiple Comparisons
Authors: Pearce S. C. 
Published: October 2008

SummaryMultiple comparison methods are described. It is noted that they have always been controversial, partly because they emphasize testing at the expense of estimation, partly because they pay no regard to the purpose of the investigation, partly because there are so many competing forms and, not least, because they can lead to illogical conclusions. There are many identified instances where they have been found misleading.An alternative approach is to designate ‘contrasts of interest’ from the start and to concentrate estimation and testing upon them. In many experiments the approach is powerful and definite in use, but sometimes there is no reason to designate one contrast rather than another, for example, in the assessment of new strains or new chemicals. In such circumstances some have found multiple comparisons useful, especially when the problem is to ‘pick the winner’. Bayesian methods and cluster analysis are considered briefly as other alternatives.The current over-use of multiple comparisons is deplored. It is thought to arise in part from bad teaching and in part from the general reluctance of non-statisticians to venture into the unknown territory of specifying contrasts. A bad situation is made worse by the availability of software that carries out multiple comparisons as a matter of course.
Clonal Responses of Tea Shoot Extension to Temperature in Malawi
Authors: Smith R. I. , Harvey F. J. , Cannell M. G. R. 
Published: October 2008

SummaryAlthough the relationship between the length of a growing tea shoot and time is not truly exponential, the exponential relative shoot extension rate (ERSER) can be used for comparisons when both the initial shoot lengths and the periods of measurement are identical. An empirical method to adjust ERSER for variations in initial shoot length was developed for weekly field measurements of seven tea clones in Malawi. ERSERs, measured throughout the two growing seasons after the bushes had been pruned, were standardized to an initial shoot length of 2.5 cm and were then related to mean weekly air temperatures and to vapour pressure deficits. There were large clonal differences in the response of ERSER to temperature within the range 18–23°C. Shoots of the vigorous Malawi clone SFS 150 elongated rapidly at all temperatures, but notably at the lower temperatures (18–20°C). Two Kenyan clones, BB/35 and K6/8, did not grow well at about 18°C, which is normal for growth in Kenya but which coincides with the period of short daylengths (less than 12 h) in Malawi. A significant decrease in ERSER was found with increased vapour pressure deficit over the whole range of field measurements and ERSERs were uniformly lower in the second year after pruning. The results suggest that the usual calculations to derive an inherent base temperature for elongation are not valid unless elongation is truly exponential and therefore, in general, base temperatures should not be used for comparisons between experiments.
A Case of Farmer Adaptation and Adoption of Contour Hedgerows for Soil Conservation
Authors: Fujisaka Sam 
Published: October 2008

SummaryAfter farmer-to-farmer training, farmers at an upland research site in the Philippines adapted and adopted contour hedgerows over a period of four years. They developed hedgerow establishment methods that required less labour, eliminated grasses that were too competitive with crops, stopped planting trees that were initially intended to produce green manures, and planted species that might provide direct cash returns. The different systems they used controlled soil erosion equally and effectively, although grazing of hedgerows by neighbours’ cattle was a problem. The farmers who learned about the technology but who did not establish contour hedgerows on their farms were those who had a higher proportion of flat land and/or off -farm or non-farm income opportunities.
Altitude, Temperature and Shoot Production of Tea in the Kenyan Highlands
Authors: Squire G. R. , Obaga S. M. O. , Othieno C. O. 
Published: October 2008

SummaryShoot production was examined for two clones at four sites in western Kenya, differing by up to 300 m in altitude and from 16.4 to 18.1°C in mean air temperature. The duration of the shoot growth cycle increased with altitude, and the rate of shoot extension decreased, mainly because of the temperature differences. Outside a dry season, linear regressions of both extension rate and 1/duration on temperature were significant for Clone S.15/10, and gave apparent base temperatures around 7.5°C, but were not significant for Clone TN.14/3 which responded only slightly to temperature. The dry weight per shoot was stable and the growing point frequency did not change systematically with altitude. Analysis that excluded the effects of drought indicated that the yield of Clone S.15/10 decreased from 740 g m-2 at the lowest site by about 10% per degree fall in temperature, whereas the yield of TN.14/3 did not change systematically with altitude.
Plant Nematodes and Sustainability in Tropical Agriculture
Authors: Page Sam L. J. , Bridge John 
Published: October 2008

SummaryAlthough plant nematodes are ubiquitous and pathogenic to a wide range of crops, research into these pests in the tropics has been concentrated on commodity crops. While modern intensive tropical agriculture has become unsustainable and often relies on the use of toxic nematicides to control damaging populations of plant nematodes, many traditional subsistence farmers have been able to suppress nematodes by promoting crop diversity and selecting for tolerance and resistance. This paper gives examples of sustainable systems which suppress nematodes. Other examples of once sustainable systems in which nematode problems now occur are discussed and reasons for this instability suggested. The need for farmers to retain responsibility for the development of sustainable systems is stressed. Nematologists and other plant protectionists are encouraged to take a wider view of the complex issues that affect the sustainability of agriculture in the tropics.Los nemátodos de las plantas y la agricultura continua
Agricultural Research Strategies for Favoured and Marginal Areas: the Experience of Farming Systems Research in Pakistan
Authors: Byerlee Derek , Husain Tariq 
Published: October 2008

SummaryThis paper draws on the results of farming systems research (FSR) conducted over five years at eight sites distributed throughout Pakistan. The main research findings with respect to the irrigated plains, or favoured areas (four sites), and the marginal mountainous and rainfed areas (four sites) are summarized, with emphasis on the role of system interactions in technology development. In favoured areas, most system interactions occur between crops grown in multiple cropping patterns, whereas in marginal areas, crop-livestock interactions dominate. Appropriate research strategies for each kind of environment are discussed. It is concluded that although there is a need for quite different research strategies for favoured and marginal areas, the methods and perspective of FSR are equally appropriate and even critical for achieving future gains in agricultural productivity in each type of environment.Estrategias de investigación agricola en zonas favorecidas y marginales: Experiencias recogidas durante la investigación de sistemas agrícolas en Pakistán
Yield and Water Use Efficiency of Faba Bean Sown at Two Row Spacings and Seed Densities
Authors: Silim S. N. , Saxena M. C. 
Published: October 2008

SummaryThe performance of promising genotypes of faba bean developed for areas with limited rainfall was compared with the local landrace, ILB 1814, at Tel Hadya in Syria during 1989–1988 using different row spacings and sowing densities. In the last two years of the trials the performance of the improved genotypes and ILB 1814 was compared with and without supplemental irrigation. Yields of ILB 1814 were better than the highest yielding genotypes in some years and similar to them in others. In seasons with limited rainfall the best yields were obtained by using a narrow row spacing and dense sowing, and yields were significantly improved by irrigation. Grain yield was correlated with biomass and the number of pods per unit area. The percentage of radiation intercepted was highest in ILB 1814, particularly when sown with a narrow row spacing and at a high plant density. Soil water extraction, evapotranspiration and water use efficiency were improved by sowing at a narrowrow spacing and high plant density.Los nemátodos de las plantas y la agricultura continua
Observations of Some Tree Root Systems in Agroforestry Intercrop Situations, and their Graphical Representation
Authors: Rao M. R. , Muraya P. , Huxley P. A. 
Published: October 2008

SummaryRoot systems of unprunedCassia siameaandLeucaena leucocephalatrees and regularly pruned hedges ofC. siamea, L. leucocephalaandGliricidia sepiumwere examined in a semi-arid area in Kenya. Trenches were dug across rows of trees or hedges, soil profiles washed, and different sized roots counted in small 5 × 5 cm grids fully covering both faces of the trench. The roots were displayed using two computer software programmes written for this purpose: a spline technique that displays smoothed root densities in different shades; and a random dot method which displays roots as dots, using any specified scale. The fine roots of four-and-a-half-year-oldC. siameapenetrated the soil to meet with rocks at depths between 0.60 and 2.0 m, and spread laterally to 9 m, traversing adjacent crop plots. Roots of eight-year-oldL. leucocephalacovered an extensive soil volume and included a greater density of fine roots thanC. siameaat comparable distances. Above-ground pruning restricted the roots of hedges to a depth of 1.5 m, although roots of different hedges spaced 5 m apart intermingled freely in the alley space.L. leucocephalaroots filled the alley very densely while those ofG. sepiumwere sparse, particularly in the middle of the alley. Rooting density ofC. siameawas intermediate. The dot method is more precise when rooting densities are low but when densities are high the splining method appears to be more visually helpful. These graphical methods greatly facilitate overall comparisons of sections of tree root systems, but quantification of root densities at different distances away from trees is still needed to understand more precisely the competitive effects of trees and associated crops.Systemas de raices de los árboles
Wheat Growth as Influenced by the Interaction of Drainage Water and Nitrogen Fertilization
Authors: Al-Abdulsalam M. A. , Al-Tahir O. A. , Al-Jasim A. A. , Burhan H. O. 
Published: October 2008

SummaryBread wheat is grown under irrigation in Saudi Arabia. Since water resources are limited, any additional agricultural development must make use of sources of water that are less than ideal, for example, saline drainage water. A two year field study was conducted to compare the effects of irrigating bread wheat with normal water, with a 1: 1 mixture of normal water and drainage water, and with drainage water alone, at three levels of nitrogen fertilizer use. The mean electrical conductivity of the irrigation water was 2.6, 8.6 and 14.6 ds m−1, respectively, in the two seasons of the study. Irrigation with drainage water decreased yield and yield components but increased the protein content of the grain of the two wheat cultivars studied. Drainage water depressed straw yields more than it depressed the yield of grain. Nitrogen application increased yield and yield components in all the irrigation treatments, partially overcoming the adverse effects of the use of saline drainage water.Efectos del agua salada y el nitrógeno en el trigo
Statistical Analysis of Field Experiments in Coconut Using Fewer Recordings
Authors: Peiris T. S. G. 
Published: October 2008

SummaryCoconut is harvested at bimonthly intervals (six picks per year) in all field experiments carried out by the Coconut Research Institute in Sri Lanka. Because recording of individual picks is costly and time consuming, it is of interest to know whether or not recording can be restricted to fewer picks without prejudicing the results of experiments. Yield data from five long-term field experiments conducted at five different locations showed that the sum of the first, third and fifth picks could provide a good estimate of the sum of six picks. Yield recording can therefore be confined to these three picks and the cost and time of recording in an experiment reduced by 50%. These three picks can conveniently be used to assess treatment effects on total annual yield.Análisis estadístico del rendimiento de coco
Effects of High Soil Surface Temperature on Seedling Survival in Pearl Millet
Authors: Peacock J. M. , Soman P. , Jayachandran R. , Rani A. U. , Howarth C. J. , Thomas A. 
Published: October 2008

SummaryA field technique to screen pearl millet genotypes for their emergence and survival at high soil surface temperatures is described. Genetic variation in seedling emergence and survival is shown and it is argued that this variation is largely due to tolerance of high temperatures rather than tolerance of soil moisture deficit, although some interaction occurred. An index for ‘thermotolerance’ is defined and genotypes are ranked accordingly for this trait, which is shown to be highly heritable. The technique is repeatable and allows a large number of genotypes to be screened at the same time.
Field Evaluation of the Possible Impact of Some Pesticides on the Soil and Water Environment in Nigeria
Authors: Sangodoyin A. Y. 
Published: October 2008

SummaryA study conducted at Ibadan, Nigeria, showed that some community water supplies were slightly polluted by the pesticides applied on adjacent farms. There was also evidence of soil degradation as a result of agrochemical use, with differences in the physico-chemical properties of soils in fields where agrochemicals had been applied and in adjacent fields that had not been cultivated. Measures that can be taken to minimize some of the environmental dangers inherent in the application of agrochemicals are discussed.