Journal and Journal Articles: Recent submissions

Now showing items 1661-1680 of 5157

    • The role of technology in agricultural intensification: the evolution of maize production in the northern Guinea savanna of Nigeria 

      Smith, J.; Barau, A.D.; Goldman, A.; Mareck, J.H. (1994)

    • Quantitative methods for assessing the severity of anthracnose on yam (Dioscorea alata) 

      Simons, S.A.; Green, K. (1994)
      Two methods (the individual leaf method and whole plant method) for the quantitative assessment of the incidence and severity of anthracnose (Colletotrichum gloeosporioides on yam were developed and evaluated in the field over 3 growing seasons and are proposed for use in epidemiological studies. The percentage leaf/plant area affected by anthracnose and therefore unable to photosynthesize was used to produce disease assessment keys.

    • The effects of alley cropping and fertilizer application on continuously cropped maize 

      Shannon, D.A.; Vogel, W.O.; Kabaluapa, K.N. (1994)
      A trial was conducted to study the long-term effects of alley cropping on maize under continuous cropping with and without fertilizer. Maize was planted twice a year for four years. Maize yields were higher with alley cropping than without alley cropping from the fourth crop onward. Fertilizer application increased yield for each crop. Average yields over the eight crops were highest for the combination of alley cropping and fertilizer application. The long-term effects of the treatments on maize ...

    • PYrenophora triticirepentis as a component of the fungal flora of winter wheat seed in New York 

      Schilder, A.M.; Bergstrom, G.C. (1994)
      The occurrence of P. tritici-repentis among the fungal flora of soft white winter wheat seed in New York, USA, was assessed during 1990-91. The fungus was recovered from 54% of the seed lots in 1990 and from 36% of the seed lots in 1991, infecting an av. of 2.1 and 0.6% of the seeds, respectively. Seed infection by fungal pathogens was generally low in 1991. Alternaria spp. were the fungi most commonly associated with soft white winter wheat seed in both years. Stagonospora [Leptosphaeria] nodorum, ...

    • Infection of wheat seed by Pyrenophora triticirepentis 

      Schilder, A.M.; Bergstrom, G.C. (1994)
      The seed infection process of Pyrenophora tritici-repentis, incitant of tan spot of wheat, was investigated, as were several influencing factors. Following inoculation of the wheat spike, P. tritici-repentis gained access to the seed by first colonizing the glume, lemma, or d after inoculation, and palea. Seed infection was first observed 3 infection incidence increased with time and with inoculum concentration. Wheat seeds were susceptible to infection by this fungus throughout most of their ...

    • Alley farming research at the International Institute of Tropical Agriculture (IITA) 

      Osiname, O.; Tonye, J. (1994)
      Alley agriculture in Africa. In Alley cropping, food crops are grown in alleys formed by hedgerows of trees or shrubs, preferably legumes. The hedgerows are cut back at planting and at intervals during cropping to provide mulch and manure for crops growing in the alleys, and to prevent shading and to reduce competition with associated food crops. The incorporation of small ruminants production by the International Livestock Center in Africa (ILCA) (Okali and Sumberg, 1985) into the alley cropping ...

    • Importation, releases, and establishment of Neochetina spp. (col., curculionidae) for the biological control of water hyacinth, Eichhomia crassipes CLil., Pontederiaceae), Benin, West Africa 

      Thielen, R.; Ajuonu, O.; Schade, V.; Neuenschwander, P.; Adite, A.; Lomer, C. (1994)
      Water hyacinth,Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae) was first reported in Bénin in 1977 and about 10 years later became the major floating water weed in the south east, obstructing boat traffic and fisheries. Water hyacinth multiplies in permanently fresh water in the swampy upper reaches of the Sô River and in tributaries of the Ouémé River. From there it is moved by wind and water flow to the coastal lagoons. The coastal lagoons are brackish during the dry season and ...

    • Stepwise approach to alley cropping technology development and transfer in the forest zone of Cameroon 

      Tonye, J.; Duguma, B.; Tiki-Manga, T. (1994)
      Two projects on alley cropping research and development have been implemented in the Forest zone of Cameroon (FZC) since 1988. Their goal was to identify the main agricultural constraints in the FZC and to introduce alley cropping in the farming systems to improve soil fertility and crop yields. The first step in the implementation process was the participatory surveys which revealed that (a) the main agricultural constraint in the FZC is low soil fertility; (b) alley cropping is an agroforestry ...

    • Effect of agroforestry woody species on earthwarm activities and physicochemical properties of warm casts 

      Kang, B.; Akinnifesi, F.K.; Pleysier, J.L. (1994)
      The effects of five agroforestry woody species (Dactyladenia barteri, Gliricidia sepium, Leucaena leucocephala, Senna siamea andTreculia africana) on the surface aasting activity ofHyperiodrilus africanus were studied in an Alfisol (Oxic Paleustalf) in southwestern Nigeria. Casting activity under the woody species decreased in the following order:Dactyladenia sp. (26.4 Mg ha-1 year-1)>Gliricidia sp. (24.4 Mg ha-1 year-1)>Treculia sp. (22.9 Mg ha-1 year-1)>Leucaena sp. (18.6 Mg ha-1 year-1)>Senna ...

    • Residue fractionation and decomposition: the significance of the active fraction 

      Vanlauwe, Bernard; Dendooven, L.; Merckx, R. (1994)
      This paper describes an incubation experiment with homogeneously 14C labeled maize-straw and its insoluble fraction. The role of the soluble fraction in the decomposition process was assessed, using three independently measured characteristics: (1) fractionation of the maize-straw, resulting in kinetically different fractions; (2) microbial biomass C and its 14C activity determined by a fumigation extraction method, and (3) the 14C activity of the released CO2-C. The fumigation extraction method ...

    • Availability and use of CDROM products in Nigerian libraries and information centers 

      Adeniran, O.R.; Adigun, T.A.; Okoh, M.I.; Eyitayo, O.T. (1994)
      A study was conducted to find out the types of CD products in Nigerian libraries and information centres, and the uses to which they are being put. The study also tried to find out the sources of funding of such products, information about users, hardware configuration, and training facilities available in the country. Of the 157 questionnaires sent out, 85 usable returns (a 54% response rate) were received. The analysis revealed that 44 libraries had at least one PC with only nine of such centres ...

    • Diploid potato germplasm derived from wild and landrace genetic resources 

      Watanabe, K.; Orillo, M.; Iwanaga, Masaru; Ortiz, R.; Freyre, R.; Perez, S. (1994)
      Diploid cultivated species, haploids derived from tetraploid cultivars, and their wildSolanum relatives were used to generate various diploid potato genetic stocks. These stocks have significant value in potato breeding because: 1) genetic diversity in the potato population can be kept variable with the diploid germplasm which confers genetic variation from wild and cultivated species; 2) crossability of this diploid germplasm is facilitated by the function of 2n gametes; and 3) high levels of ...

    • Relative roles of wind, crop seeds, and cattle in the dispersal of Striga species 

      Berner, D.K.; Cardwell, K.; Faturoti, B.; Ikie, F.; Williams, O. (1994)
      In field trials conducted in Nigeria during 1991-92, the factors affecting the seed dispersal of Striga spp. were evaluated. Petrolatum-coated microscope slides placed at regular intervals from S. hermonthica plants and suspended from trees at 1-, 2- and 3-m above-ground heights within and around infested fields indicated that distribution of seeds of this weed by wind was not extensive. The max. horizontal distance away from S. hermonthica plants that seeds were caught was 12 m, and the max. ...

    • Preliminary evaluation of secondary Musa polyploids at IITA breeding station 

      Ortiz, R.; Vuylsteke, D. (1994)
      Secondary triploids were produced by crossing primary tetraploids with selected diploid partners and the parthenocarpic banana (Galeo). Comparisons between secondary tetraploids and secondary triploids showed that the secondary tetraploids generally had lower yields than secondary triploids. The percentage of clones selected was also higher in the secondary triploids than for secondary tetraploids, which demonstrates the more efficient breeding potential of the former. Nevertheless some resistant ...

    • Impacts of agricultural management practices on soybean and corn crops evident in groundtruth data and thematic mapper vegetation indices 

      Thenkabail, P.; Ward, A.D.; Lyon, J. (1994)
      Vegetation indices from Landsat-5 Thematic Mapper (TM) observations on single dates in August 1988, a drought year, and August 1989, a year with wet early season conditions, were used to study the impact of agricultural management and cultural practices on soybean (Glycine max) and corn (Zea mays) crop growth and yield. Management and cultural practices studied included date of planting, tillage, soil association, drainage, plant density, and stress factors. Crop ground-truth information consisted ...

    • Thematic mapper vegetation indices for determining soybean and corn growth parameters 

      Thenkabail, P.; Ward, A.D.; Lyon, J.; Merry, C.J. (1994-04)
      The use of thematic mapper data to study crop growth parameters has primarily been conducted with hand-held and truck-mounted radiometers. In addition, most studies have not used mid-infrared bands to develop vegetation indices. This study used Landsat thematic mapper data and crop parameter data from corn and soybean fields in northern Ohio (1) to develop plant-water sensitive vegetation indices that included the mid-infrared, near-infrared, and red bands; and (2) to compare the ability of different ...

    • Landsat 5 thematic mapper models of soybean and corn crop characteristics 

      Thenkabail, P.; Ward, A.D.; Lyon, J. (1994)
      This study used Landsat-5 Thematic Mapper (TM) data to develop empirical models for determining soybean and corn crop yield, leaf area index, wet biomass, dry biomass and plant height. Ground-truth data was obtained from more than 50 commercial farms in Ohio, USA, during 1988 and 1989. Several significant linear, non-linear, logarithmic, exponential, and power models were developed. The best soybean models generally comprised of information from the commonly-used bands 3 and 4. TM data for the ...

    • Biological control of the cassava mealybug, Phenacoccus manihoti (Homoptera: Pseudococcidae), in Zambia 

      Chakupurakal, J.; Markham, R.H.; Neuenschwander, P.; Sakala, M.; Malambo, C.; Mulwanda, D.; Banda, E.; Chalabesa, A.; Bird, T.; Haug, T.M. (1994)
      Surveys were carried out in Zambia twice yearly from 1986 to 1990, to assess the impact of a biological control campaign against the cassava mealybug (CM), Phenacoccus manihoti Mat.-Ferr., throughout the infested area. From 1984 onward, the exotic parasitoid Epidinocarsis lopezi (De Santis) (Hym., Encyrtidae) and some exotic coccinellid predators were released on 54 occasions along the spreading front of CM infestation. E. lopezi established in every release site, spread, and covered the entire ...

    • Variability of chloroplast DNA and nuclear ribosomal DNA in cassava (Manihot esculenta Crantz) and its wild relatives 

      Fregene, M.; Vargas, J.; Ikea, J.; Angel, F.; Thome, J.; Asiedu, Robert; Akoroda, M.; Roca, W. (1994)
      Chloroplast DNA (cp) and nuclear ribosomal DNA (rDNA) variation was investigated in 45 accessions of cultivated and wild Manihot species. Ten independent mutations, 8 point mutations and 2 length mutations were identified, using eight restriction enzymes and 12 heterologous cpDNA probes from mungbean. Restriction fragment length polymorphism analysis defined nine distinct chloroplast types, three of which were found among the cultivated accessions and six among the wild species. Cladistic analysis ...

    • Influence of leaf age, soil moisture, VPD and time of day on leaf conductance of various Musa genotypes in a Humid Forest Moist Savanna transition site 

      Ekanayake, I.J.; Ortiz, R.; Vuylsteke, D.R. (1994)
      Leaf age effects on the leaf conductance to water vapour diffusion of the adaxial and abaxial leaf surfaces were measured in the morning and in the afternoon on 17 different plantain and banana (Musa spp.) genotypes. The irradiance levels increased three-fold while leaf to air vapour pressure deficit levels increased two- to four-fold from morning to afternoon during the sampling period in a field site located in the humid forest-moist savanna transition zone of Nigeria. Conductance values were ...