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Conference Documents: Recent submissions
Now showing items 281-300 of 726
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A regional experiment to test green manure cover crops and evaluate the role of Internet based networking
(2000)Land degradation in the West African subregion is threatening the food security and livelihoods of both rural and urban populations. Green manure cover crops have the potential of reversing such trends. A wide range of stakeholders have been involved in the promotion of these technologies and it became apparent that a network was needed to provide a common forum where these cover crop enthusiasts could discuss their problems and identify opportunities for synergy. With the advancement of ICT ... -
An approach for the evaluation of herbaceous legumes with multiple benefits
(2000)In order to promote the identification of herbaceous legumes that may contribute to weed control, soil fertility, crop production, and livestock enterprises, as a means of encouraging sustainable agricultural practices amongst resource-poor farmers, an evaluation method using a simple sampling approach is described. To illustrate the method, result from one experiment in the derived savanna of Nigeria conducted over a period of 2.5 years are presented. The experiment included 14 accessions of ... -
Detection of mislabeled germplasm in cocoa collections using DNA fingerprinting with SSR markers
(2006)Incorrect labeling of cocoa accessions is a significant that has hindered the efficient conservation and use of cocoa germplasm. The United States Department of Agriculture (USDA), together with the international collaborating institutions, has undertaken a program to identify the cocoa genotypes and describe the genetic diversity in the major international and national cocoa collections maintained in the Americas. To date, a total of 4027 coca accessions maintained in the two international genebanks ... -
Suitability of Pueraria phaseoloides, Chromoleana odorata and Tithonia diversifolia for nematode management in Musa cropping systems
(2006)Mulching with plant organic matter has been shown to reduce nematode population densities in various cropping systems. The level of nematode control is increased when such mulches are incorporated into the soil as organic amendments. Chromolaena odorata, Tithonia diversifolia and Pueraria phaseoloides are common cover crops in West and Central Africa that produce large quantities of nutrient rich biomass. The aim of this study was to determine, if in-situ mulching of C. odorata, T. diversifolia ... -
Estimation of symbiotically fixed nitrogen using extended N difference methods
(1992)There are limitation to all methods currently available for estimating symbiotically fixed nitrogen. This paper evaluates the I5N dilution and N difference methods, and reports on the results of field experiments conducted with faba beans (Viciafaha) and peas (Pisum sativum). The objectives of these experiments were to investigate whether the limitations of the N difference method, hitherto the least-used method, could be overcome, to study the effect of extending the simple N difference method, ... -
Amelioration of a highly degraded tropical alfisol by planting 1. Changes in soil physical and chemical properties
(1992)This paper examines soil amelioration by planting 15 leguminous and graminaceous plant species, including herbaceous annuals, perennials and biennials, and woody perennials and biennials. Disturbed and undisturbed natural regrowth were planted with leguminous species, in some cases with fertilizer applied at planting (400 kg ha- of 15: 15: 15 NPK). The studies were made on two highly degraded sites in southwestern Nigeria which had been subjected to intensive mechanized cropping for a period of ... -
Comparative study on the growth and productivity of Sesbania and leucaena in the Central Plateau region,Rewanda
(1992)A study was conducted in the Central Plateau region of Rwanda to assess the productivity ofSesbania sesban and three Leucaena species in hedgerow intercropping systems. S. sesban grew and accumulated biomass most rapidly in the first 10 months of growth. During the following 6 months the fastest growth was observed in L. diversifolia (provenance Rwanda). After cutback, regrowth from S. sesban dropped whereas in the Leucaena species it increased. S. sesban produced more stakes than the Leucaena ... -
Five years of research on improved fallow in the semiarid highlands of Rwanda
(1992)Alternative technologies that maximize the use oflocal resources and improve the sustainability of crop production in Rwanda are needed. Promising species for the semi-arid highlands, where the research reported in this paper was conducted, include mucuna (Mucunaprwiens) for fallow periods of 1 4- 1 8 weeks, sunnhemp (Crotalaria ochroleuca), pigeonpea (Cajanus cajan) and desmodium (Desmodium distortum) for fallow periods of 20-24 weeks, and Sesbania sesban and Tephrosia vogelii for long fallows ... -
Response of some tropical nitrogenfixing woody legumes to drought and inoculation with mycorrhiza
(1992)This paper reports on a study of the influence ofdrought and inoculation with mycorrhiza on dry-matter production, nutrient uptake and water relations of Acacia auriculiformis, Albizia lebheck. Gliricidia sepium and Leucaena leucocephala in a sterile soil. Inoculation with L. leucocephala roots containing vesicular-arbuscular mycorrhizal (VAM) fungi (Glomus and Acaulospora spp.) resulted in infection of 25-68% in regularly watered plants. Drought stress reduced infection by 8-49%. In general, VAM ... -
Fitting soilimproving legumes into inland valley ricebased cropping systems in West Africa
(1992)Because of their favourable hydrology, the small inland valleys of West Africa offer the possibility of sustainable increases in food crop production. A key component in any sustainable cropping system is the maintenance or restoration of soil fertility. This paper explores avenues for introducing biological nitrogen fixation management into existing cropping systems. A description of one system has allowed the identification of possible niches for leguminous species. Various activities are being ... -
Effect of fertilizatin and Rhizobium inoculation on the growth of Leucaena and Gliricidia on an Alfisol in southwestern Nigeria
(1992)The aim of the research reported here was to compare the early growth and nodulation of Leucaena leucocephala and Gliricidia sepium, grown in pots containing soils of differing fertility obtained from alley farms. The plants' response to nitrogen and phosphorus fertilizers and to inoculation with rhizobia was also assessed. The application of the fertilizers, separately or combined, in the low-fertility soil increased plant height and shoot dry-matter and nitrogen yield at 84 days after planting. ... -
Early growth and symbiotic properties of three woody legumes grown on a sandy soil in southwestern Nigeria
(1992)The early growth and symbiotic properties ofthree woody legumes, Cassia siamea, Gliricidia sepium and Leucaena leucocephala, were monitored on a farmer's field and in the screenhouse using the same soil. L. leucocephala and G.. septum nodulated freely and were heavily infected by native vesicular-arbuscular mycorrhizal fungi. Six months after planting, G. sepium had the highest dry-matter production, percentage of mycorrhizal infection, nodule number, dry weight and nitrogenase activity per plant ... -
Biological nitrogen fixation in trees in agroecosystems: twenty years of biological nitrogen fixation research in Africa.
(1992)With the low input of fertilizers into African farming systems, it is necessary to harness biological nitrogen fixation to its fullest extent. The greatest potential, at least in the short term, lies in nitrogen fixation in grain and pasture legumes and in nitrogen-fixing trees. To maximise nitrogen fixation in these plants and under various cropping systems requires intensified research. Inoculation techniques and inoculum production in Africa are not yet advanced, and this is unlikely to change ... -
Potential role of transgenic approaches in the control of cowpea insect pests
(2002)Crops' incompatibility makes conventional breeding approaches untenable in transferring available insect resistance From wild Vigna sp. into cowpea. The alternative recourse is to isolate and transfer alien resistance genes using genetic transformation. This has the added advantage of using useful genes from distantly related organisms to control cowpea pests. Artificial diet bioassays carried out on the Maruca pod borer, pod sucking bugs, and cowpea weevils indicate that these insects can be ... -
Insecticidal activities of the African yam bean seed lectin on the development of the cowpea beetle and the pod sucking bug
(2002)The cowpea beetle, Callosobruchus maculatus, and pod-sucking bug, Clavigralla tomentosicollis, are two of the major insect pests of cowpea in Africa. A lectin was purified from the seeds of the African yam bean (AYB), Sphenostylis stenocarpa, by affinity chromatography on Galactosc-Sepharose 4B. The purified AYB lectin (AYBL) was tested on the two insect pests of cowpea. When C. maculatus larvae were fed on artificial cowpea seed containing 0.2, 2, and 5% (w/w) of dietary lectin, larval mortality ... -
Regeneration and genetic transformation in cowpea
(2002)Over the last three decades, sporadic efforts have been made to develop regeneration and transformation systems in cowpea ( Vigna unguiculata L. Walp). This paper reviews the progress made to date, including highlights of culture media and explants used for regeneration and chimeric gene constructs employed in transformations. Progress has been slow, mainly due to limited resources, since very few laboratories have been involved. There is an urgent need for more focused and consistent efforts to ... -
Breeding cowpea varieties for resistance to Striga gesnerioides and Alectra vogelii
(2002)Two parasitic flowering plants, Striga gesnerioides (Wild.) Vatke and Alectra vogelii (Benth.), cause substantial yield reduction in cowpea in the dry savannas of sub-Saharan Africa. Alectra is more prevalent in the northern Guinea savanna and southern Sudan savanna of West Africa, as well as in East and southern Africa whereas Striga is mostly found in West and Central Africa. However, both are fast spreading beyond these limits. Collaborative studies with national and regional programs have ... -
Recent genetic studies in cowpea
(2002)A number of recent studies have added further information on the genetics of important traits in cowpea. These include inheritance of qualitative traits such as plant pigmentation; flower color; seed color; seed coat texture; resistance to rust, scab, smut, nematode, severe mosaic virus, Striga, Alectra, aphid, bruchid, heat; drought tolerance; and male sterility, and quantitative traits such as protein content, seed size, seed yield, and fodder quality. A few studies on linkage and mapping have ...
