bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plant Genetic Resources and Plant Improvement as Tools to Develop Sustainable Agriculture
Authors: Ceccarelli S. , Valkoun J. , Erskine W. , Weigand S. , Miller R. , Van Leur J. A. G. 
Published: October 2008

SummaryThis paper addresses the current and future contributions of plant genetic resources and plant improvement to sustainable agriculture with reference to the activities of the International Center for Agricultural Research in the Dry Areas (ICARDA) in association with national programmes in West Asia and North Africa. These regions constitute the primary centres of diversity of crops such as wheat, barley, chickpea and lentil. Genetic erosion is being curtailed by germplasm collection and preservation. Selection for low-input cultivars of barley is conducted under low input conditions, and new cultivars of lentil and barley are often intentionally heterogeneous to stabilize their performance in dry rainfed areas. The importance of genetic differences in the cultivars on subsequent crops in the rotation and on straw quality for livestock is under study. Insect pests and diseases contribute to yield instability. Because of the potential adverse impact of pesticides on the fragile ecosystems of the region, integrated control strategies based on agronomic management, host plant resistance, biological control agents and strategic use of selective insecticides are being developed.
Fruiting Activity, Growth and Yield of Oil Palm. I. Effects of Fruit Removal
Authors: Corley R. H. V. , Breure C. J. 
Published: October 2008

SummaryThe relation between current yield and future yield components in the oil palm (Elaeis guineensis Jacq.) was investigated by removing a proportion of inflorescences before anthesis. This disbudding caused mean fruit bunch weight to increase by over 60%, with corresponding increases in the components of bunch weight. The total number of inflorescences produced increased by 10%, the sex ratio increased from 72 to 91% females, and inflorescence abortion and bunch failure rates were halved. As a result, the number of bunches harvested was reduced by less than the level of disbudding, and removal of 75% of inflorescences only reduced yield by 42%. Disbudded palms also grew more vigorously. The time intervals between a change in the level of fruiting activity and the resulting changes in yield components were determined by recording the yield components during the period after disbudding was stopped.
Fruiting Activity, Growth and Yield of Oil Palm. II. Observations in Untreated Populations
Authors: Breure C. J. , Corley R. H. V. 
Published: October 2008

SummaryThe extent to which the number and weight components of oil palm fruit yield are affected by the total weight of fruit bunches on the palm (fruiting activity) was investigated by multiple regression analysis, with plant available water and sunshine hours as additional covariates. Fruiting activity significantly increased the percentage of aborted inflorescences six months after leaf opening, and reduced the ratio of female to total inflorescences (sex ratio) seven to eight months prior to leaf opening. Mean weight of bunches was negatively affected by fruiting activity ten to eleven months before harvest, the number of flowers per spikelet and the mean single fruit weight being the only components to show a clear response. Fruiting activity significantly reduced the petiole cross sectional area of leaves six months before opening.Simulation models for oil palm yield forecasting must take account of the endogenous yield cycles resulting from these effects of fruiting activity.
Changing Concepts in Crop Plant Evolution
Authors: Hutchinson Sir Joseph 
Published: October 2008

SUMMARYEvolutionary studies in the cottons began with the demonstration by Harland that true cottons could be divided into four genetically distinct species, each carrying an internally balanced genotype that was disrupted in crosses with any other. Harland's genetic classification has stood the test of time, and contributes substantially to our understanding of speciation in other genera, as for example,Phaseolus. In addition, it provides a genetic basis for the observations described by Anderson as ‘introgression’.Studies of cottons found growing wild, and of their relationship to cultivars in the same areas, led to the hypothesis that all true cottons are cultivars, and those now found wild are escapes. This hypothesis, though it led to purposeful exploration of the distribution and relationships of the cottons, was found to be inadequate. A new approach to the relationships of the cottons became possible following Thoday's demonstration of ‘disruptive selection’ inDrosophila. The disruptive situation has been shown to obtain as between cultivars and their wild relatives inSorghumand in a number of other crop plants.Consideration of the time scale of agricultural evolution makes it clear that the recent origin theory is untenable, and a review of the status of the ‘wild’ cottons shows that they are adequately accounted for as weedy relatives of the cultivars, descended from common wild ancestors under disruptive selection.It is concluded that crop plant evolution has gone on very largely within the balanced gene pools which Harland regarded as genetic species.
Effects of Soil Moisture Stress on Two Varieties of Upland Cotton in Israel. III. The Bet-She'an Valley
Authors: Marani A. , Amirav A. 
Published: October 2008

SUMMARYThe effects of moisture stress during various stages of the development of two varieties of upland cotton (Acala 4–42 and Deltapine Smoothleaf) were studied in two irrigation experiments in the Bet-She'an valley, where summer temperatures were high and evapotranspiration in the fully irrigated treatments was up to 8–10 mm./day in July and August. Optimum time for first irrigation in the Bet-She'an valley was two or three weeks before flowering and six or seven irrigations, if timed to prevent moisture stress, were sufficient to give high yields and good lint quality. Lint yield ranged from 270 kg./ha. in non-irrigated to 2000 kg./ha. in the fully irrigated treatments in 1966.
The Incidence of Climatic Conditions Favourable to Coffee Berry Disease in Kenya
Authors: Waller J. M. 
Published: October 2008

SUMMARYClimatic conditions affecting the development of CBD are assessed by measuring wetness within the tree canopy and air temperature. Saturation of the tree canopy, necessary for spore dispersal, occurs most frequently at the tops of trees and the duration of wetness permitting spore germination is most prolonged at night. Night air temperatures are closest to berry temperatures and are important in assessing infection periods. Disease development in 1968 and 1969 was related to the number of infection periods during the growing season. Polythene tree covers which kept trees sufficiently dry to stop disease development were used in determining infection at different times of the year.
Effects of Fertilizing and Other Factors on Yams in Barbados
Authors: Gooding E. G. B. 
Published: October 2008

SUMMARYIn 1968–9 and 1970–1 small-scale experiments were set up on over a hundred farms in Barbados, simple enough for farmers to carry out with a minimum of supervision. Results were obtained from more than 70 in each year. NK fertilizing gave no increase in yield in 1968–9, but a significant increase of 800 lb per acre in 1969–70. In each year NPK gave a highly significant increase of 1000 lb per acre. There was also a general increase in yield with increasing rainfall up to about 40 inches during the growing season and with closer than normal spacing especially under conditions of low rainfall. Planting later than usual led to marked decreases in yield.
Early Results from a Trial of Upper Amazon Cocoa Clones in Ghana
Authors: Lockwood G. 
Published: October 2008

SUMMARYYields in a trial of Upper Amazon clones, derived from high yielding Upper Amazon selections, were low in the early years. One Upper Amazon clone was significantly higher yielding than any other clone, but generally yields from the Upper Amazons were comparable to those of Local Trinitario selections included as controls. The Upper Amazon clones were highly variable in establishment, yield and losses from diseases. The relationship between the performance of some of the clones and their parent seedlings is discussed.
Leguminous Cover Crops for Maintaining Soil Fertility in Sisal in Tanzania II. Effects on Moisture Status of Soil and Sisal
Authors: Hopkinson D. 
Published: October 2008

SUMMARYThe effect of covers of controlled volunteer vegetation, Pueraria phaseoloides, and clean weeding on the soil moisture content and on the succulence of sisal leaves was studied. The surface soil tended to dry out further when exposed by clean weeding, but moisture in the profile as a whole was not much depleted. The plant covers dried soils to at least 300 cm. in dry periods. Although sisal leaves had a slightly higher dry matter content in dry weather there was no evidence of competition for water between the plant covers and the sisal.
Nitrogen Mineralization in West Indian Soils
Authors: Cornforth I. S. 
Published: October 2008

SUMMARYSoil properties influencing N mineralization, and hence the potential N-supplying power of 154 West Indian soils, have been studied. Mineralizable N was correlated with the activity of the soil biomass measured as extractable glucose, with exchangeable bases in base-deficient soils and with total N in soils well supplied with bases, but not with other estimates of the nature of soil organic matter (e.g. extractable chlorophyll or C : N ratio). It is suggested that cation exchange capacity and percentage base saturation may influence the N-supplying power of West Indian soils more than their total N content.
A Method for Studying the Distribution of Absorbing Roots of Fruit Trees
Authors: Weller F. 
Published: October 2008

SUMMARYA method is described for studying the distribution of absorbing roots of fruit trees using the number of light root tips per unit of soil space as a criterion for characterizing the spatial distribution of the absorbing parts of the root systems. As examples of the use of this method, some results are shown from investigations with apple trees in South-Western Germany. They demonstrate the influence of soil-type and soil management on the distribution of absorbing roots. Striking temporal variations in the number of root tips were observed in the same tree.
Yield and Plant Development of Reduced Cotton Stands in Malawi
Authors: Matthews G. A. , Rowell J. G. , Beeden P. 
Published: October 2008

SUMMARYYield response to a range of plant densities (0·7–7·2 plants m.−2) achieved by uprooting plants at random was curvilinear, with an optimum plant density of 3·3 plants m.−2 at which fertilizer increased the yield at Makoka by over 1000 kg. ha.−1 to 2227 kg. ha.−1. There was no interaction between fertilizer and plant density. At Ngabu there was no response to fertilizer. Top dressing was effective on unfertilized cotton at Makoka, but filling in was ineffective at both sites. A method of partitioning components of yield is described which illustrates the stages of plant development which benefitted or were adversely affected by the different agronomic practices.
Seed Rate, Time of Thinning and Weeding of Cotton in Malawi
Authors: Matthews G. A. , Beeden P. 
Published: October 2008

SUMMARYExperiments on seed rate, time of weeding and thinning confirmed that lower seed rates, weeded and thinned early, give higher yields. A reduction in yield of 400 kg.ha.−1 seed cotton caused by late weeding emphasized that farmers who spray should limit their acreage to that which can be weeded satisfactorily.
Oil, Protein and Dry Matter Development in Sesame Seed
Authors: Khidir M. O. , Khattab A. H. 
Published: October 2008

SUMMARYA three-year study on the development of oil, protein and dry matter in sesame seeds showed that oil percentage increased rapidly 11–17 days after fertilization, reaching a maximum in 20–23 days. There was no change in the iodine value of the oil after 18 days from fertilization. Accumulation of protein was more gradual, but there was no appreciable increase after the ‘seeds’ were 27 days old. Dry matter increased more slowly than either oil or protein and there was little increase after the ‘seeds’ were 34 days old. The implications of these findings on problems of harvesting the crop are discussed.
Effects of Artificial Defoliation (Simulating Pest Damage) on Varieties of Upland Rice
Authors: Taylor W. E. 
Published: October 2008

SUMMARYArtificial defoliation was used to simulate grazing by cutting-grass or cane-rat (Thryonomys swinderianus), on three rices with durations of 110–115, 130–135 and 140–145 days respectively, defoliated before, during and soon after tillering by removing leaves to half, two-thirds and the total height of the plants. All varieties showed marked compensatory growth, resulting in increased tillering and yield, especially when defoliated during tillering, but yield fell when foliage was removed after tillering, especially with shorter duration rice. Defoliation to half the height of the plant during tillering had the most beneficial effect, whereas removal of all leaves to soil level after the tillering stage had the most adverse effect.
Soil Temperature and Leaf Expansion in Zea mays
Authors: Watts W. R. 
Published: October 2008

SUMMARYMaize plants (Sweetcorn cv. Earliking) were grown in plots where four types of soil surface coverings were used to induce soil temperature differences During the vegetative stage of growth measurements were made of total leaf area per plant on a daily basis, and relative rates of leaf area increase were found to be closely correlated with mean daily soil temperatures at 5 cm. depth. The results were consistent with evidence that the temperature of the apical meristem strongly influences rates of leaf expansion in maize seedlings.
Uptake of Sulphur and other Nutrients by Groundnuts (Arachis hypogaea) in Northern Nigeria
Authors: Bromfield A. R. 
Published: October 2008

SUMMARYThe uptake of S followed a similar pattern to dry-matter production by groundnuts given enough fertilizer-S to prevent S-deficiency. The fastest rate at which dry matter was produced was 140 kg./ha./day. Of the 6857 kg./ha. at harvest, 3401 were in haulm, 967 in shells and 2489 in kernels. S was taken up fastest during the eighth week, when the daily average was 0·22 kg./ha.; at harvest, of the 11·6 kg./ha. in the plants, 5·4 was in the haulm, 0·8 in shells and 5·4 in the kernels. Of the 157 kg. N/ha. in the harvested crop 62 per cent was in shells and kernels and of the 13·5 kg. P/ha., 64 per cent was in shells and kernels.
Effects of Clone and Irrigation on the Stomatal Conductance and Photosynthetic Rate of Tea (Camellia sinensis)
Authors: Smith B. Gail , Burgess Paul J. , Carr M. K. V. 
Published: October 2008

SummaryStomatal conductances (g) and photosynthetic rates (A) were monitored in six tea clones planted in a clone X irrigation experiment in the Southern Highlands of Tanzania. Measurements were made during the warm dry seasons of 1989 and 1990. There was no genotype X treatment interaction in the response in A or g of the various clones to irrigation. Irrigation increased A more than it increased g. Irrigation also increased the temperature optimum for photosynthesis and decreased photo-inhibition at high illuminance. Clones differed in g and A, and in the relationship between leaf temperature and A. The implications of these findings for clone selection are discussed.
Towards the Reliable Prediction of Time to Flowering in Six Annual Crops. IV. Cultivated and Wild Mung Bean
Authors: Ellis R. H. , Lawn R. J. , Summerfield R. J. , Qi A. , Roberts E. H. , Chay P. M. , Brouwer J. B. , Rose J. L. , Yeates S. J. , Sandover S. 
Published: October 2008

SummaryEight genotypes of cultivated mung bean, black gram and rice bean (Vigna mungo, Vigna radiatassp.radiataandVigna umbellata, respectively) were sown at six sites in Australia on various dates in order to provide a range of photothermal environments. In addition, four accessions of the related wild speciesVigna radiatassp.sublobatawere sown on five occasions. Times from sowing to first flowering (f) varied between environments from 34 to 317 d; pre-flowering temperature and photoperiod means ranged from 12.7° to 29.1°C and from 11.8 to 15.5 h d−1. No effect of photoperiod was detected on rate of progress towards first flowering (1/f) in four genotypes, but in each case a significant positive relation was detected between 1/fand mean temperature. These simple thermal time relations did not differ significantly among these four genotypes; the common base temperature was 7.9°C. In two genotypes observations were well described by a thermal response plane when the mean photoperiod was less than 13 h d−1(p < 0.01) but photoperiods greater than 14 h d−1delayed flowering. In each of the remaining genotypes the observations were best described by photothermal planes, that is, 1/fwas modulated by temperature and photoperiod. Predictions from the models based on our data were in good agreement with the times to first flowering observed in three genotypes in an earlier controlled environment study.
Evaluation of Stored Maize Losses in Cameroon
Authors: Mchugh Dermot 
Published: October 2008

SummaryFarmer surveys have consistently shown maize storage losses to be of primary concern to farmers in the western highlands of Cameroon. Past attempts at evaluating these losses, however, have proved to be unsatisfactory, mainly because of failure to consider qualitative, as well as quantitative, losses or to take account of consumption patterns (that is, timing and end use). A simulation model is presented that overcomes these deficiencies while providing a reliable estimate of the economic value of storage losses to the farmer, albeit at the cost of requiring fairly exacting data. The model is used to estimate the value of storage losses to farmers in the North West Province of Cameroon.
Yield Performance of Yam Bean in Tonga, South Pacific
Authors: Grum M. , Halafihi M. , Stölen O. , Sørensen M. 
Published: October 2008

SummaryTwenty one accessions of yam bean (PachyrhizusRich. ex DC.) were tested in yield trials under short day conditions in Tonga, South Pacific. Fresh weight tuber yields ranged from 5.3 to 72.0 t ha−1, dry matter content from 8.0 to 20.8% and dry matter yields from 1.20 to 8.57 t ha−1. Crude protein content of peeled tubers varied between 5.1 and 9.8% of dry matter, yielding 71–540 kg ha−1of crude protein. Varietal variation in leaf defoliation by the rose beetle,Adoretus versutusHar., was noted.
Low Input Technology Options for Millet-based Cropping Systems in the Sahel
Authors: Klaij M. C. , Renard C. , Reddy K. C. 
Published: October 2008

SummaryPearl millet is a staple cereal cultivated mainly by subsistence farmers on 14 million ha of the West African semi-arid tropics. Increasing pressure on the land has reduced the length of the fallow periods, which are necessary to restore soil fertility, resulting in declining yields. To investigate ways of reversing this decline, three systems combining phosphorus fertilizer application, improved varieties of millet and cowpea, and improved agronomic practices were compared with the traditional millet–cowpea intercrop system in a three year experiment. The most productive system involved the rotation of fertilized millet and cowpea. Pre-sowing tillage increased hay and fodder yields in all the improved systems. The application of fertilizer increased the amount of available phosphorus in the soil. Soil pH declined somewhat in all treatments, although the initially low soil organic matter did not change.
Crop and Soil Responses to Post-emergence Tillage and Weed Control in Lowland Rice
Authors: Siopongco Joel D. L. C. , Ingram Keith T. , Pablico Paquito P. , Moody Keith 
Published: October 2008

SummaryBeusani is a rice crop management system practised in rainfed lowland areas of eastern India whereby rice is dry-seeded, then wet-ploughed at 30–50 days after emergence and the land levelled by drawing a board across the field. Field experiments showed that beusani enhances rooting, especially in shallow soil layers, as a result of reduced penetration resistance. Although beusani reduced weed biomass by 38%, it was not as effective as application of herbicide followed by hand weeding, which reduced biomass by 87%. Yields were directly related to weed control, so beusani treatments did not yield as much as the herbicide plus hand weeding treatments in these experiments.
Towards the Reliable Prediction of Time to Flowering in Six Annual Crops. V. Chickpea (Cicer arietinum)
Authors: Ellis R. H. , Lawn R. J. , Summerfield R. J. , Qi A. , Roberts E. H. , Chay P. M. , Brouwer J. B. , Rose J. L. , Yeates S. J. , Sandover S. 
Published: October 2008

SUMMARYFour genotypes of ‘desi’ and two of ‘kabuli’ chickpea (Cicer arietinum) were sown at six locations in Australia on various dates between 1986 and 1988, giving 22 combinations of site and sowing date with diverse photothermal environments. Times from sowing to first flowering (f) varied from 30 to 162 d, mean pre-flowering temperatures from 10.8° to 29.3°C and mean photoperiods from 11.3 to 15.6 h d−1. There was no evidence that any observation had been obtained in photoperiods shorter than the ceiling photoperiod (Pcc) or longer than the critical photoperiod (Pc). This suggests that, in typical agricultural environments, chickpea crops experience photoperiods (P) which should satisfy the condition Pcce < P < Pc. In one ‘kabuli’ and two ‘desi’ genotypes, 1/f was influenced by both temperature and photoperiod. The coefficient of determination (R2) for a linear, additive rate of development model ranged from 0.74 to 0.80, with no significant difference in either temperature sensitivity or photoperiod sensitivity among these three genotypes. In the remaining three genotypes, no significant response to temperature was detected between 10.8° and 29.2°C, so rate of progress to flowering was influenced solely by photoperiod. There was no significant difference in the sensitivity of 1/f to P among these three genotypes. The linear, additive rate model found here to be so satisfactory as a predictive tool for phenology, is also shown to have much wider general application.Predicción del liempo de floración
Integration of Forage and Food Crops Grown Sequentially on Vertisols under Rainfed Conditions in the Mid-Altitude Ethiopian Highlands
Authors: Tedla Abate , Sherington J. , Mohamed-Saleem M. A. 
Published: October 2008

SUMMARYPoor drainage of Vertisols in the Ethiopian mid-altitude highlands limits farming operations and cropping in the early rainy season (July–August). Traditional crops are grown on residual moisture late in the season (September–January) when waterlogging is less of a problem. Productivity is therefore below its potential. The recent introduction of a broadbed and furrow system for improved drainage on Vertisols allows full use of the growing period and provides scope for a wider variety of cropping systems and increased productivity. Trials using a sequential cropping system demonstrated that two crops a year can be grown when Vertisols are drained. The crops used in the trial were oats or an oat/vetch mixture forage in the early season followed by grasspea or chickpea food crops in the late season as the second crop. Further on-farm research on sequential cropping of forages and food crops in the mid-altitude highlands of Ethiopia is now needed.