bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of On-farm Rice Yield Data from India
Authors: Simmonds N. W. , Talbot M. 
Published: October 2008

SummaryData recently published in this journal on grain yields of new rice varieties, grown under rainfed conditions on-farm in two villages in Uttar Pradesh, were analysed. The new varieties were spectacularly better than the landraces with which they were compared and showed a high regression slope (>2) against the landraces. If supported by further studies, such experiments could provide an appropriate, but hitherto unexplored, approach to plant breeding for poor, small farmers operating with low inputs.
Comparison of Oilseed Crops with Wheat and Barley in a Dry Mediterranean Climate
Authors: Hadjichristodoulou A. 
Published: October 2008

SummaryThe best available varieties of barley, durum wheat, rapeseed, safflower and sunflower were compared for their yield of grain and oil and other traits under rainfed conditions and with supplementary irrigation in the relatively dry Mediterranean climate of Cyprus. The grain yields of the oilseed crops safflower and rapeseed when grown under conditions of plentiful rainfall or with supplementary irrigation were 3–5 t ha−l. Considering the high prices of oilseeds on the world market, the income from oil crops compares favourably with that from barley and wheat. However, under conditions of limited rainfall (300 mm) and without supplementary irrigation the yields of oilseed crops were extremely poor, at the most 0.6 t ha−1. Grain and oil yields of irrigated safflower and rapeseed were larger than those of sunflower. Among the oilseed crops, sunflower received most irrigation water and rapeseed the least. Under rainfed conditions, with precipitation less than 300 mm, cereals were the only successful crops. It is concluded that in the high rainfall areas of West Asia and North Africa, or with supplementary irrigation, including treated municipal wastewater, oilseed crops can be successfully grown.
Production Possibility Frontiers and Estimation of Competition Effects: The Use ofA PrioriInformation on Biological Processes in Intercropping
Authors: Ranganathan Radha 
Published: October 2008

SummaryProduction possibility frontiers contribute much to an economic evaluation of yield advantages from intercropping. The difficulty with estimating a production frontier empirically from experimental data is one of ascertaining that the fitted curve corresponds with the frontier. This problem has been overcome by deriving the frontier froma prioriknowledge of the biological processes that determine the outcome in intercropping. The hyperbolic relationship between biomass yield and plant density, and the parameters that characterize the degree of intra-and inter-specific competition in intercropping are used in this paper to derive production possibility frontiers. The method is illustrated with data from three intercropping studies. A brief review of the two main methods used by researchers to evaluate the results of intercropping, and their limitations, is also presented.
Use of Tine-tillage, with Atrazine Weed Control, to Permit Earlier Planting of Maize by Smallholder Farmers in Zimbabwe
Authors: Shumba E. M. , Waddington S. R. , Rukuni M 
Published: October 2008

SUMMARYBecause of shortages of oxen for mouldboard ploughing, delayed planting of maize is common in Mangwende, Zimbabwe and reduces grain yield by 32%. On-farm experiments over four years tested the possibility of using a ripper tine, with atrazine herbicide, to allow smallholders to plant maize earlier. Compared to mouldboard ploughing, tine cultivation increased grain yield at 13 out of 18 sites. All these sites had less than 240 mm of rainfall in January (which coincided with crop anthesis) and long term rainfall records suggest tine cultivation should raise yields in two out of three years. Handweeding and atrazine treatments gave similar grain yields when used with tine cultivation, provided weeds were controlled within 14 days of crop emergence. Tine cultivation was economic at sites where the yield was greater than that with the mouldboard plough. The farmers could manage the combination of tine and atrazine use on a field scale.
Adaptation of Lentil to the Mediterranean Environment. I. Factors Affecting Yield Under Drought Conditions
Authors: Silim S. N. , Saxena M. C. , Erskine W. 
Published: October 2008

SummaryLentil frequently suffers from drought stress towards the end of the growing season in rainfed Mediterranean farming systems. This study aimed to quantify the contribution of yield potential under irrigated conditions and of drought escape to the adaptation of lentils to drought, and to identify traits of value in selection for adaptation to a rain-fed Mediterranean environment. Twenty-five diverse lentil lines were sown under both irrigated and rainfed conditions in the 1987/88 and 1988/89 seasons in northern Syria. In 1987/88 the total seasonal rainfall was 403 mm and average rainfed biomass and seed yields were 5.0 and 1.8 t ha-l, respectively. In contrast, in 1988/89 the total season rainfall was 180 mm and average biomass and seed yields were only 0.67 and 0.12 t ha-1, respectively. Early vigour (estimated as a visual score) and percentage ground cover were strongly associated with final biomass, and were of value in predicting economic yield (seed + straw). Early maturity was correlated with seed yield. In the dry season 1988/89, 49% of the variation in seed yield among lines was accounted for by variation in flowering time. Drought escape was clearly the key response to drought. For severely drought-prone areas, selection for early flowering is therefore required. Variation in flowering time and seed yield under irrigated conditions accounted for 62% of seed yield variation under drought stress.
Adaptation of Lentil to the Mediterranean Environment. II. Response to Moisture Supply
Authors: Silim S. N. , Saxena M. C. , Erskine W. 
Published: October 2008

SummaryLentil is generally grown as a rainfed crop in areas of West Asia and North Africa where rainfall is highly variable. This study aimed to measure genetic responses to variation in moisture supply in the yield of seed and straw, evapotranspiration and water use efficiency, to guide the lentil breeding programme. The response of 25 diverse lentil lines to a soil water gradient was studied in 1987/88 and 1988/89 at Breda, northern Syria, using a line-source sprinkler system. The coefficient of determination between rainfed and irrigated seed yield in the dry 1988/89 season was r2 = 0.26, and the genotypes that were well adapted to dry conditions were different from those well adapted to wet conditions. However, there were also widely adapted genotypes that yielded well under both wet and dry conditions. The selection of such genotypes might be appropriate for the region receiving 300–400 mm annual rainfall, in contrast with the approach to selection suggested for drier areas (less than 300 mm annual rainfall) in a companion article. Soil moisture extraction from the time of maximum profile recharge to maturity in 1987/88 and cumulative crop evapotranspiration in the 1987/88 rainfed crop did not differ among lentil lines. In the irrigated treatment, however, evapotranspiration in the medium to late maturing lines exceeded that in the early maturing lines towards maturity.
The Impact of Varying Levels of Competition from Pearl Millet on the Yields of Groundnut Cultivars
Authors: Ndunguru B. J. , Williams J. H. 
Published: October 2008

SummaryA series of trials investigated the response of a range of groundnut genotypes to varied levels of competition from millet in intercrop situations in both the Sahelian and Sudanian agro-climatic zones. No genotype interactions were observed in response to different millet population levels. Introducing millet into groundnut cultivation provided considerable benefits to the farmer, particularly at the less dense millet populations, but the introduction of groundnut into millet cropping consistently reduced the yield of millet, with little gain in groundnut yields.
Collecting Meaningful Data on Labour Use in On-Farm Trials in Sub-Saharan Africa
Authors: Spencer Dunstan S. C. 
Published: October 2008

SummaryIn order to measure the effects of new agricultural technologies on labour productivity in sub-Saharan Africa, on-farm trials are usually conducted using small plots. Farmers who keep no records have to be interviewed frequently to minimize the effect of memory loss on the accuracy of the data collected. In this paper, results are reported of experiments in the forest zone of Nigeria and the semi-arid Sahel of Niger. They show that if researchers can take steps to fix events in the memory of farmers, accurate labour use data can be collected in interviews as long as three months after the events being recalled. A range of plot sizes, with a minimum of 350 m2 in the forest zone, needs to be used to measure accurately labour use per hectare and to take into account the effect of economies of size on crop production.Recopilacón de datos significatiaos sobre el use de mano de obra en estudios realizados en fincas del sub-Sahara africano
Effect of Heat and Drought Stress on Sorghum (Sorghum Bicolor). I. Panicle Development and Leaf Appearance
Authors: Craufurd P. Q. , Flower D. J. , Peacock J. M. 
Published: October 2008

SummarySeven sorghum lines, flowering from 50 to 87 days after sowing, were subjected to early drought stress, late stress, and both early and late stress in the field during the dry season in India. Panicle initiation was delayed by 2–25 days and flowering by 1–59 days by the drought stress treatments, the greatest effect being in the treatment subjected to both early and late stress. Stress increased the period between panicle initiation and flowering by retarding the rate of panicle development; when stress was severe panicle development stopped. Upon relief of stress following irrigation, panicle development resumed at rates comparable to those in a fully irrigated control. The rate of leaf appearance was affected in a similar manner to panicle development soon after water was withheld. Rate of leaf appearance and panicle development decreased as pre-dawn leaf water potential decreased and ceased at water potentials of −0.55 and −0.7 MPa, respectively.
Effect of Heat and Drought Stress on Sorghum (Sorghum Bicolor). II. Grain Yield
Authors: Craufurd P. Q. , Peacock J. M. 
Published: October 2008

SummaryThree early and four later flowering lines of sorghum were subjected to three drought stress treatments (early, late and early plus late stress) in the field during the dry season at Hyderabad in India. Mean diurnal temperature and evaporation rate were uniformly high throughout the experiment. The late and early plus late stress conditions were severe, while the early stress was mild.Grain yield was affected by both the timing and the severity of the stress. The largest reduction (87%) in grain yield resulted from stress imposed during booting and flowering (late stress) in the early flowering lines; the same stress treatment on vegetative plants had no effect on grain yield. Increasing the duration of severe stress on vegetative plants (early plus late stress) reduced grain yield by 50–60%.Grain yield was strongly and positively correlated with the number of grains m-2. Variation in grain yield was associated with variation in total dry matter rather than with harvest index, which was only reduced when stress occurred at flowering. Treatment effects on thermal growth rates (g m-2 °Cd-1) during the phase from booting to flowering confirmed that growth during this phase is the major determinant of yield potential (number of grains). The importance of phonology in research into drought resistance is discussed.
Methods of Identifying Genetic Diversity in Gliricidia Species for Biomass Production
Authors: Chamberlain J. R. , Galwey N. W. 
Published: October 2008

SummaryGliricidia sepium is a leguminous tree native to Mexico and Central America, and is utilized for fuelwood, animal fodder and green manure in rural communities. It is widely distributed throughout the tropics, but many populations of the tree have arisen from haphazard introductions of unknown quality. Methods for determining the genetic structure and origin of populations are therefore required as a basis for genetic improvement. In order to test the effectiveness of various measures of genetic diversity, provenances of G. sepium from Panama, Guatemala, Mexico and Honduras were studied by electrophoresis of seed storage proteins and the enzymes leucine aminopeptidase (LAP) and acid phosphatase (ACP), and by measurement of plant morphological characteristics. Study of seed storage proteins and morphological characters was very informative, and there was some genetic variation for ACP, but LAP showed no clear variation. In the cases where genetic variation was present, the different methods of study showed a consistent pattern of variation: genetic diversity was greatest in the population from Honduras, and least in that from Panama. This was contrary to expectations on the basis of the locations of origin of the populations and the range in which G. sepium is believed to be native. Electrophoresis of the storage proteins of Gliricidia maculata confirmed the status of this species as a distinct taxon.
Late Planting Effects on Early Versus Late Pearl Millet Genotypes in Niger
Authors: Reddy K. C. , Visser P. L. 
Published: October 2008

SummaryThe performance of two contrasting pearl millet (Pennisetum glaucum) genotypes was compared following five planting dates under rainfed conditions in deep sandy soils at Bengou, Niger in 1986 and 1987. The early and partially photo-sensitive cultivar HKB yielded more grain than the late and photo-sensitive cultivar Somno when planted with the first two seasonal rains. But after delayed planting, the crop growth rate and harvest index of cultivar HKB were reduced, leading to smaller grain yields even though the growth period, rainfall, radiation and temperature were similar at all the planting dates. In contrast, cultivar Somno maintained a small but stable harvest index over various planting dates, so that although its growth period and crop growth rate were reduced by delayed planting, the reduction in grain yield was less. Since agronomic manipulation, such as increased plant density and fertilizer application, can be used to increase crop growth rate, photo-sensitive millet genotypes such as cultivar Somno could be used for late July plantings in the Sudano-Sahelian zone.
Lodging in Lentil as Affected by Plant Population, Soil Moisture and Genotype
Authors: Ibrahim M. , Erskine W. , Hanti G. , Fares A. 
Published: October 2008

SummaryThe effects of levels of soil moisture and plant population on lodging and associated losses from mechanical harvesting of two lentil genotypes, one susceptible and one resistant to lodging, were investigated during 1986–87 and 1987–88 at Tel Hadya in northern Syria. High plant population increased lodging because the crowded plants had thin stems, while high levels of soil moisture caused lodging because biological yield was increased. When biological yields were high a two tonne increase in biological yield led to a one point increase in lodging score. Mechanical harvesting increased losses in biological yield due to lodging by 12% compared with yields obtained by hand harvesting under rainfed conditions and by 24% at the highest level ofsoil moisture. It is suggested that supplementary irrigation should be used in dry seasons in trials to select genotypes resistant to lodging.Decaimiento de la lenteja
Adaptation of Extra Short Duration Pigeonpea to Rainfed Semi-Arid Environments
Authors: Chauhan Y. S. , Johansen C. , Singh Laxman 
Published: October 2008

SummaryThe adaptation of extra short duration (ESD) pigeonpea (Cajanus cajan) genotypes to rainfed environments was studied on Alfisols and Vertisols at the ICRISAT Center between 1987 and 1989. Despite a slightly shorter crop duration, the grain yield of ESD genotypes was twice as large on Alfisols as on Vertisols. On both soil types, the rate of growth and grain yield were better in crops sown on time than in those where sowing was delayed. The population levels necessary to maximize yield varied among genotypes on Alfisols, where the grain yield of several ESD genotypes compared favourably with that of ICPL 87, a standard short duration genotype. However, none of the ESD genotypes yielded more than ICPL 87 on the Vertisols.
Towards the Reliable Prediction of Time to Flowering in Six Annual Crops. II. Soyabean (Glycine Max)
Authors: Summerfield R. J. , Lawn R. J. , QI A. , Ellis R. H. , Roberts E. H. , Chay P. M. , Brouwer J. B. , Rose J. L. , Shanmugasundaram S. , Yeates S. J. , Sandover S. 
Published: October 2008

SUMMARYEleven genotypes of soyabean (Glycine max) of tropical, sub-tropical and temperate origin and one accession ofG. sojawere grown in six locations in Australia during 1986–88, and at one location in Australia and two in Taiwan during 1989–91. Dates of sowing were varied within and among locations so as to expose plants to as many as 32 environments of widely different diurnal temperature and daylength. Times from sowing to flowering (f) were recorded, from which rates of progress towards flowering (1/f) were calculated. These derived data were then related to mean pre-flowering values of temperature (T¯) and photoperiod (P) using a three-plane linear model developed from controlled environment data. Among genotypes, mean values offvaried between 24–49 d and between 139–291 d in the most- and least-inductive environments, respectively. These differences were associated with variations in P from about 11 to 16 h d-1, in daily mean maximum temperatures from about 17° to 36°C, in daily mean minimum temperatures from about 5° to 25°C, and in T¯ from about 11° to 30°C, that is, a very wide range of photothermal regimes. The relations of 1/fto T¯ and P can be described in photoperiod-insensitive genotypes by a thermal plane defined by two constants,aandb, and additionally by a photothermal plane defined by three constants, a′, b′ and c′, in the more numerous photoperiod-sensitive genotypes. If photoperiod-sensitive genotypes are grown in sufficiently long days then a third photoperiod and temperature-insensitive plane is exposed, defined by a constant, d′; this plane indicates the maximum delay in flowering of which the genotype is capable. The constants a′, b′, c′ and d′ define the delay in flowering caused by photoperiod-sensitivity genes. The two intercepts between the three planes define, respectively, the critical photoperiod, Pc, above which increase in daylength delays flowering, and the ceiling photoperiod, Pcc, above which there is no further delay. The values of the six constants for any genotype can be estimated from observations of fin several natural environments. Comparisons between years in Australia and between Australia and Taiwan show that these genotypic constants can predict 1/f, and so the time taken to flower, given data on latitude, sowing date and daily values of maximum and minimum air temperatures. This model is more accurate than an alternative logistic model; we also believe that all six constants in the three-plane rate model described here have biological meaning. They indicate separate genetic control of flowering responses to P and T¯ and could form a rational basis for the genetic characterization and analysis of these responses in the soyabean germplasm.Pronóstico del momento de floración II
Comparison of Extra-Short-Duration Pigeonpea With Short-Season Legumes Under Rainfed Conditions on Alfisols
Authors: Nam N. H. , Chauhan Y. S. , Johansen C. 
Published: October 2008

SUMMARYExtra-short-duration pigeonpea (Cajanus cajan) genotypes generally yielded more than short-season legumes when sown at the normal time on rainfed medium-deep Alfisols. However, their growth and yield were more reduced by delayed sowings and varied more widely between seasons than those of the short-season legumes, especially cowpea and black gram. All the crops gave lower yields on shallow Alfisols than on medium-deep Alfisols and none was consistently superior. Partitioning of dry matter into grain yield was less affected by time of sowing, soil and season in extra-short-duration pigeonpea genotypes than in short-season legumes. Less sensitivity of biomass accumulation to various abiotic constraints is therefore a major objective in improving the adaptation of extra-short-duration pigeonpea genotypes.Cajanus cajan de duración extra-corta
Effects of Soil Moisture and Vapour Pressure Deficits on Shoot Growth and the Yield of Tea in the Kenya Highlands
Authors: Odhiambo H. O. , Nyabundi J. O. , Chweya J. 
Published: October 2008

SUMMARYProlonged moisture stress and high vapour pressure deficits reduced the shoot water potential, shoot population density, rate of shoot extension and yield of clonal tea. The more drought susceptible Clone 6/8 had a lower shoot water potential, rate of shoot extension, number of shoots per unit area, rate of shoot regeneration and yield than the more tolerant Clones 31/8, 57/15 and 15/10 during the periods of low soil moisture, which coincided with high vapour pressure deficits. The changes in the shoot growth components could be used as an index of the suitability of different clones for different regimes of soil moisture and vapour pressure deficits.Factores ambientales que afectan el rendimiento del té
Effects of Intercropping Young Plants of the Compact Arabica Coffee Hybrid Cultivar Ruiru 11 with Potatoes, Tomatoes, Beans and Maize on Coffee Yields and Economic Returns in Kenya
Authors: Njoroge J. M. , Waithaka K. , Chweya J. A. 
Published: October 2008

SUMMARYThe effects of intercropping young plants of the compact arabica coffee hybrid cultivar Ruiru 11 with potatoes, tomatoes, maize and Phaseolus (dry) beans were studied between 1987 and 1989 at Ruiru in Kenya. Yields of clean (hulled) coffee were reduced by the maize intercrop by 59–100%. Coffee bean size, and raw, roast and liquor quality were not significantly affected by the potato, tomato and bean intercrops, which gave positive net economic benefits. Potatoes planted between all the coffee rows gave the largest marginal rate of economic return, followed by tomatoes in combination with beans. The technically and economically viable intercrops for coffee were potatoes, tomatoes, beans, and tomatoes in combination with beans.Siembra simultánea de café Araébica y cultivos para la alimentatión
Optimizing Fertilizer Use and Practical Rainfall Capture in a Semi-Arid Environment with Variable Rainfall
Authors: Piha M. I. 
Published: October 2008

SummaryFertilizer use in the semi-arid tropics is considered risky because of the unreliable rainfall pattern. A flexible system of fertilization was devised which allowed for high yields in wet years, and reduced financial losses in dry years. Relatively immobile nutrients, such as phosphorus, potassium and sulphur, were applied at rates determined from generalized soil properties and the total nutrient uptake required for a crop to achieve its maximum yield potential in a season with average rainfall. Nitrogen was applied as a series of split applications, which were adjusted during the season according to the degree of water stress observed. This approach was tested in on-farm trials for maize production on nutrient-poor sandy soils in three regions of Zimbabwe, and resulted in larger yields and profits than current recommendations, providing an accept able level of financial return. Small further yield increases were possible, at acceptable returns, when these fertilizer practices were combined with the establishment of tied-ridges by ox-drawn implements, 30 days after planting. By careful estimation of yield potential, and appropriate adjustments to soil fertility, this system of soil management could be applied to other cropping situations and other areas with variable rainfall.Uso de fertilizantes para condiciones de precitación variable