Journal and Journal Articles: Recent submissions

Now showing items 1841-1860 of 5157

    • Poverty and child farm labour in Africa: wealth paradox or bad orthodox 

      Nkamleu, G.B. (2006)
      The link between poverty and child labor has traditionally been regarded as well established but recent researches have questioned its validity, suggesting that child labor is more important in the richest households (wealth paradox). The present study revisits the link between poverty and farm child labor in Africa and aims at testing the paradoxical wealth effect. Using different modeling techniques, the analysis focuses on family-controlled child labor taking place in the cocoa sector of Côte ...

    • Charge characteristics of soil organic matter fractions in a Ferric Lixisol under some multipurpose trees 

      Oorts, K.; Vanlauwe, Bernard; Cofie, Olufunke O.; Sanginga, N.P.; Merckx, R. (2000)
      Soil organic matter (SOM) has a key role in maintaining soil fertility in weathered soils in the tropics. This study was conducted to determine the contribution of different SOM fractions to the cation exchange capacity (CEC) of a tropical soil as influenced by organic matter inputs of different biochemical composition. Soil samples were collected from a 16-yr old arboretum established on a Ferric Lixisol, under five multipurpose tree species: Leucaena leucocephala, Dactyladenia barteri, Afzelia ...

    • Nitrogen contribution of five leguminous trees and shrubs to alley cropped maize 

      Okogun, J.; Sanginga, P.; Mulongoy, N. (2000)
      There are abundant local legume trees and shrubs potentially suitable for alley cropping systems in the sub-Saharan Africa, which are yet to be studied. The nitrogen contribution of two years old Albizia lebbeck and S. corymbosato yield of maize grown in alley cropping was compared to that of Senna siamea, Gliricidia sepium and Leucaena leucocephala in four seasons at Ibadan. Maize shoot biomass and maize grain yield in A. lebbeck alley compared favourably with that in G. sepium and L. leucocephala. ...

    • Response of maize (Zea mays) to phosphorus application on basaltic soils in Northwestern Cameroon 

      Osiname, O.; Meppe, F.; Everett, L. (2000)
      A field trial was conducted on two P sorptive, basaltic soils commonly used for maize production in Northwestern Cameroon. The objective was to determine the maintenance P rates required for adequate P supply in the soils for maize after initial capital dressing applications of P (0, 22, 44, 88 and 132 kg ha-1) in 1991. These were followed by three supplementary P rates – 0, 44 and 88 kg ha-1 in 1992. Three crops of maize (cv COCA) were grown to monitor the availability of the residual P. Experimental ...

    • Biological effects of African yam bean lectins on the cowpea coreid bug, Clavigralla tomentosicollis (Stal) 

      Okeola, O.G.; Machuka, J. (2001)
      The biological effects of affinity purified seed lectin from African yam bean, Sphenostylis stenocarpa (Harms), were tested on Clavigralla tomentosicollis (Stål) in an artificial seed system. S. stenocarpa was extracted from two African yam bean accessions: Enugu 95-3 and Enugu 98-2. Lectins from both accessions were highly toxic to the insect at 1.0% dry weight. For nymphs feeding on Enugu 95-3 and Enugu 98-2, survival ranged from 16.0 to 24.0% and 4.0 to 16.0% at 1.0 and 2.0% dry weight dietary ...

    • Effectiveness of rhizobia nodulating recent promiscuous soyabean selections in the moist savanna of Nigeria 

      Sanginga, P.; Thottappilly, G.; Dashiell, Kenton E. (2000)
      The ability of soybean to nodulate with a wide range of indigenous bradyrhizobia has been used in a breeding programme since 1997 in Nigeria. As far as is known, these indigenous bradyrhizobia strains have not been tested for compatibility and effectiveness with recent selections from a breeding programme which has proceeded without input from soil microbiologists for the last 20 yr. Twenty bradyrhizobia strains isolated from soyabean and cowpea grown in Ibadan and Zaria soils in Nigeria were ...

    • Effect of legume management on forage production and residual effects on upland rice 

      Schulz, S.; Keatinge, J.D.H.; Wells, G.; Shrestha, R. (2000)
      An experiment was conducted over the period 1995–96 in a warm‐temperate environment in Nepal to investigate the effect of cutting frequency on forage yields of three temperate legume species, grown during the winter season, and the residual treatment effects on a subsequent upland rice crop. The three species, Persian clover (Trifolium resupinatum), white clover (Trifolium repens) and vetch (Vicia benghalensis), proved to be well adapted to the winter growing conditions and produced cumulative ...

    • Host plants and population dynamics of the cob borer Mussidia nigrivenella Ragonot (Lepidoptera: Pyralidae) in Benin 

      Sétamou, M.; Schulthess, F.; Poehling, H.; Borgemeister, C. (2000)
      The ear borer Mussidia nigrivenella Ragonot is a polyphagous insect pest that feeds on various cultivated and wild plants. Surveys in four agro-ecological zones of Benin, conducted between 1993 and 1997, revealed ≈20 plant species from 11 plant families hosting the borer, but only 13 host plants enable the borer to develop to the pupal stage. Whereas, a maize crop usually supports one generation per season, several generations of M. nigrivenella were recorded on Parkia biglobosa (Jacq.) Benth. and ...

    • Identification of a defective molecule derived from DNAA of the bipartite begomovirus of East African Cassava Mosaic Virus 

      Ndunguru, J.; Legg, J.; Fofana, B.; Aveling, T.; Thompson, G.; Fauquet, C. (2006)
      Geminivirus defective interfering DNAs arise spontaneously in mechanically inoculated test plants, and have previously been found with DNA‐B of the bipartite cassava mosaic geminiviruses, but not DNA‐A. Reported here for the first time is the cloning and characterization of a naturally occurring truncated form of cassava mosaic geminivirus DNA‐A, which at 1525 nt is around half the expected full size. Sequence analysis has shown it to be a defective (df) form of East African cassava mosaic virus ...

    • Spatial distribution of and sampling plans for Mussidia nigrivenella (Lepidoptera: Pyralidae) on cultivated and wild host plants in Benin 

      Sétamou, M.; Schulthess, F.; Poehling, H.; Borgemeister, C. (2000)
      The spatial distribution of Mussidia nigrivenella Ragonot was studied in maize fields and on four major wild host plants in the Republic of Benin, West Africa. Maize ears were sampled at harvest in 1994 and 1995, and fruits of the wild host plants were collected monthly from January 1996 to December 1997 during the fruiting periods of the respective host species. The spatial distribution was analyzed using the variance-to-mean ratio (s2/m), an index of departure from Poisson distribution, Iwao's ...

    • Monitoring and modeling of field infestations and damage by the maize ear borer Mussidia nigrivenella Ragonot (Lepidoptera: Pyralidae) in Benin, West Africa 

      Sétamou, M.; Schulthess, F.; Poehling, H.; Borgemeister, C. (2000)
      In many countries in West Africa, the pyralid ear borer Mussidia nigrivenella Ragonot occasionally causes severe damage to pre- and postharvest maize. Between 1992 and 1995, the distribution of and damage caused by M. nigrivenella were studied in Benin using survey data and an on-station field experiment. The borer was distributed across the whole country, and at maturity an average 25% of the ears sampled in maize fields were infested. Damage levels varied with agro-ecological zones and were ...

    • Parisitisme des Loranthaceae sur lavocatier (Persea americana, Lauraceae) dans la region de Yaounde (Cameroun) 

      Sonke, B.; Kenfack, D.; Tindo, M. (2000)
      In Cameroon, parasitism by Loranthaceae is a limiting factor of the avocado tree cultivation as well as the many diseases and pests which have been better studied. Inventories were carried out in the agroecosystems of five localities around Yaounde, Cameroon. In each one of these localities, all the avocado trees likely to produce and located within a perimeter 2000 m×50 m were observed and characterized by the circumference of the trunk, the number of tufts of Loranthaceae present on the tree and ...

    • Genetics of rough seed coat texture in cowpea 

      Singh, B.B.; Ishiyaku, M. (2000)
      Seed coat texture is an important trait in determining the acceptability of cowpea varieties in different regions. A rough seed coat is preferred in western and central Africa, since it permits easy removal of the seed coat which is essential for indigenous food preparations. On the other hand, a smooth seed coat is preferred in eastern and southern Africa as well as in parts of South America where cowpea is consumed as boiled beans without removing the seed coats. This study was undertaken to ...

    • Variability of Peronosclerospora sorghi isolates from different geographic locations and hosts in Africa 

      Bock, C.H.; Jeger, M.J.; Mughogho, L.K.; Cardwell, K.; Mtisi, E.; Kaula, G.; Mukansabimana, D. (2000)
      Nine isolates of Peronosclerospora sorghi from maize, sorghum and wild sorghum were sampled from Zimbabwe, Zambia, Rwanda, Mozambique and Kenya. They were compared for variation in conidium and conidiophore morphology, temperature requirements for sporulation, germination and germ-tube growth and for pathogenicity on different sorghum and maize cultivars. Although there were significant differences in isolate morphology, all conformed to the known range for P. sorghi. Mean conidial length×width ...

    • West African yam seeds stored under desiccated and cold storage conditions are orthodox 

      Daniel, I.; Ng, N.Q.; Tayo, T.; Togun, A. (2000)
      Yam (Dioscorea spp., family Dioscoreaceae) is one of the most important food crops cultivated in the West African yam zone comprising the forest and savannah areas of Nigeria, Ghana, Cote d'Ivoire, Republic of Benin, and Togo, which account for more than 90% of the 4.59 million ha of yam cultivation worldwide (1). A survey was conducted in 2005 to document viruses in yams in Ghana, Togo, and the Republic of Benin. Samples (1,405) from five species of yam showing mosaic, chlorosis, and stunting as ...

    • Remote sensing and GIS modeling for selection of a benchmark research area in the inland valley agroecosytems of West and Central Africa 

      Thenkabail, P.; Nolte, C.; Lyon, J. (2000)
      This paper presents and illustrates a methodology for rational selection of benchmark research areas (or benchmark watersheds) for technology development research activities in the inland valley (IV) agroecosystems of West and Central Africa. This was done through a two-tier characterization approach. The Level 1 characterization involved macro-scale sub-continental- level secondary agroclimatic and soil datasets to produce 18 agroecological and soil zones (AESZ), each of over 10 million hectares, ...

    • Control of sorghum downy mildew of maize and sorghum in Africa 

      Bock, C.H.; Jeger, M.J.; Cardwell, K.F.; Mughogho, L.K.; Sherington, J. (2000)
      In Africa, sorghum downy mildew (SDM), caused by Peronosclerospora sorghi, infects both sorghum and maize. Systemic infection can result in severe yield loss. The effects of seed treatments and foliar sprays of metalaxyl on the disease were determined on maize in Nigeria (1992) and sorghum in Zimbabwe (1993/4). Seed treatment at 1.0 g a.i/kg or a foliar spray at 0.96 g a.i./l significantly reduced the incidence of the disease, although the latter was less consistent. The effect on yield was less ...

    • Mucuna spp. suppresses speargrass (Imperata cylindrica) and increases maize yield 

      Akobundu, I.O.; Udensi, U.E.; Chikoye, D. (2000)
      Speargrass, Imperata cylindrica (L.) Raeuschel, is a serious weed, threatening crop productivity in smallholder farms in West Africa. Since the use of more effective practices such as deep tillage and chemical control is beyond the means of resource-poor farmers who carry out most agricultural activities in this region, low-input alternative technology needs to be developed. Field studies were conducted during the 1993/1994 and 1995/1996 growing seasons to investigate the influence of three ...

    • Efficiency of Gryon fulviventris (Hymenoptera: Scelionidae) as an egg parasitoid of Clavigralla tomentosicollis Stal. (Hemiptera: Coreidae) in northern Nigeria 

      Asante, Stephen K.; Jackai, L.E.N.; Tamo, M. (2000)
      Field surveys were conducted on cowpea and pigeon pea in 1995 and 1996 to assess the effect of indigenous egg parasitoids on populations of Clavigralla tomentosicollis Stål in northern Nigeria. From the egg masses of C. tomentosicollis, three species of Hymenoptera belonging to three families, namel Anastatus sp. (Eupelmidae), Ooencyrtus utetheisae (Risbec) (Encyrtidae), and Gryon fulviventris (Crawford) (Scelionidae), were recorded. Among them, G. fulviventris was found to be the most abundant ...

    • Cultural characteristics, morphology, and variation within Claviceps africana and C. sorghi from India 

      Muthusubramanian, V.; Bandyopadhyay, Ranajit; Rajaram Reddy, D.; Tooley, P. (2006)
      Sorghum ergot in India is caused by Claviceps africana and C. sorghi. The distributions of these two species in India is not known. Eighty-nine sorghum ergot isolates were cultured from young sphacelia obtained from male sterile sorghum plants artificially inoculated using inoculum collected in the field. Based on cultural characteristics, the isolates were separated into two groups which differed distinctly in the morphology of their sphacelia, conidia, and sclerotia. Marked differences also were ...