Journal and Journal Articles: Recent submissions

Now showing items 2081-2100 of 5273

    • Genetic parameters for agronomic characteristics: 1: early and intermediate breeding populations of Open Access potato seed 

      Ortiz, R.; Golmirzaie, A.M. (2003)
      The original variation in the source population as well as the selection method may influence the genetic variation in further cycles of genetic improvement. Therefore, the objectives of this research were to determine genetic parameters (variance components and heritability) in source and intermediate stages of a true potato seed (TPS) breeding population and to calculate the genetic and phenotypic correlations in this breeding material developed by the Centro Internacional de la Papa (CIP). The ...

    • An international public partnership for genetic enhancement of cowpea using a holistic approach to biotechnology 

      Ortiz, R. (2003)
      Cowpea is the most important product in African dryland agriculture. Its protein-rich grains are the main product of the crop, which are commonly eaten in different forms by rural and urban peoples. African farmers growing cowpea in their fields often harvest low yields because many biotic and abiotic factors affect the crop. Cultural practices, together with genetic manipulation through breeding (including biotechnology), can ameliorate yield-limiting factors affecting the farming of cowpea in ...

    • Dynamics of refuge use: diurnal vertical migration of predatory and herbivorous mites within cassava plants 

      Onzo, A.; Hanna, R.; Zannou, I.; Sabelis, M.W.; Yaninek, J.S. (2003)

    • Can introduced and indigenous rhizobial strains compete for nodule formation by promiscuous soybean in the moist savanna agroecological zone of Nigeria? 

      Okogun, J.A; Sanginga, N. (2003)
      Promiscuous soybean lines have been bred on the basis that they would nodulate freely without artificial inoculation. However, our recent studies have demonstrated that the indigenous rhizobia are not able to meet their full nitrogen (N) requirement. Rhizobia inoculation might be necessary. We examined the competition for nodule formation among native Rhizobia spp. and two inoculated Bradyrhizobia strains (R25B indigenous strain and a mixture of R25B+IRj 2180A indigenous strain from soybean lines ...

    • Effects of cassava genotype, climate, and the Bemisia tabaci vector population on the development of African cassava mosaic geminivirus (ACMV) 

      Abdullahi, I.; Atiri, G.I.; Dixon, Alfred G.O.; Winter, S.; Thottappilly, G. (2003)
      A survey was carried out in the 1996/97 and 1997/98 growing seasons on a field planted in three replicates with five clones of cassava at the International Institute of Tropical Agriculture, Ibadan, located in a transition forest, to determine the effects of cassava genotype and climate on the development of African cassava mosaic geminivirus (ACMV) and changes in the Bemisia tabaci population. Cassava genotype, climate and their interactions have significant

    • Genotypic differences in concentration and bioavailability of kerneliron in tropical maize varieties grown under field conditions 

      Oikeh, S.O.; Menkir, A.; Maziya-Dixon, B.; Welch, R.; Glahn, R. (2003)
      Iron deficiency is estimated to affect over one-half the world population. Improving the nutritional quality of staple food crops through breeding for high bioavailable iron represents a sustainable and cost effective approach to alleviating iron malnutrition. Forty-nine late maturing tropical elite maize varieties were grown in a lattice design with two replications in

    • Stratification and synthesis of crop–livestock production systems using GIS 

      Jagtap, S.S.; Amissah-Arthur, A.A. (1999)
      Population increases, land-use changes and marketing opportunities are important factors affecting crop-livestock integra- tion particularly with respect to their effect on soil fertility and feed supply for ruminant livestock. As the human population density rises, crop farmers and grazers are finding it profitable to establish contracts for paddocking, and they are reaching agreement on equitable ways to make use of crop residues and take care of livestocks. As the processes of intensification ...

    • Les sols de lAsie topicale humide 

      Dudal, R.F.; Moormann, F.; Riquier, J. (1974)

    • Effects of residue management on earthworm cast production after Chromolaena odorata short fallow in the humid tropics 

      Norgrove, L.; Nkem, J.N.; Hauser, S. (2003)
      We aimed to quantify the relative impact of slashing, mulching, burning and cropping on surface casting by earthworms and whether effects were due to treatments per-se or to the changes in soil temperature and water content they may induce. Surface cast production was monitored during two maize cropping seasons and the subsequent fallow phase. Slashing the vegetation caused a severe decline in surface casting activity, whether or not the plot was cropped afterwards. There was a significant interaction ...

    • A physiologically based tritrophic metapopulation model of the African cassava food web 

      Gutiérrez, A.P.; Yaninek, J.S.; Neuenschwander, P.; Ellis, C.K. (1999)
      The metapopulation dynamics of the African cassava food web is explored using a physiologically based tritrophic model. The interacting species are cassava, cassava mealybug and its natural enemies (two parasitoids, a coccinellid predator and a fungal pathogen), and the cassava greenmite and its natural enemies (two predators and a fungal pathogen). The metapopulation model is based on a single patch age-structured population dynamics model reported by Gutierrez et al. (Gutierrez, A.P., Wermelinger, ...

    • Notillage effects on soil properties and maize (Zea mays L. ) production in western Nigeria 

      Lal, R. (1974)
      The grain yields in the no-tillage plots were equivalent to those of conventionally plowed treatments. No-tillage treatments had higher organic matter content and, by controlling soil erosion, the silt and clay content than the plowed plots. The water holding capacity and moisture release characteristics of the surface soil horizon were significantly different for the two tillage treatments. A decrase in the maximum soil temperature and favourable moisture regime in the no-tillage plots stimulated ...

    • Grouping locations for efficient cassava evaluation in Malawi 

      Mkumbira, J.; Mahungu, N.M.; Gullberg, U. (2003)
      Cassava, a crop widely adapted in the tropics, has the important attribute of withstanding adverse environmental conditions better than do many other staple crops. The performance of an individual genotype, however, is influenced by the environment in which it grows. In Malawi, the heterogeneity of agro-ecologies requires the cumbersome and costly assessment of new cassava genotypes at many sites. This study was conducted, therefore, to test the feasibility of selecting only a few locations for ...

    • Leaves metabolomic profiling of Musa acuminata accessions using UPLC–QTOF–MS/MS and their antioxidant activity 

      Sonibare, M.A.; Ayoola, I.O.; Gueye, B.; Abberton, M.T.; D'Souza, R.; Kuhnert, N. (2018-01-25)
      Musa acuminata (Musaceae) is a wild species native to South East Asia. In addition to its potential as a food crop, different non-food morphological parts of the plant have been investigated for various pharmacological activities, including anticholinesterase and antioxidant activity. This study aimed to characterize Musa leaf extracts based on their phenolic composition and their agro-morphological traits. A metabolomic approach was applied to discover biomarkers that can be used to separate eight ...

    • Effect of pre-reatment processes on physicochemical aspects of vacuum-fried banana chips 

      Udomkun, Patchimaporn; Innawong, B. (2018-09-27)
      The objective of this study was to investigate the influence of various pre‐treatments on the physicochemical and sensory characteristics of vacuum‐fried (VF) banana chips (120°C, 41.3 kPa) and consequently compare them to atmospheric‐fried (AF) banana chips (170°C). Pre‐treatments comprised of osmotic dehydration with sucrose solution (ODSu), osmotic dehydration with salt solution (ODSa), microwave heating (MV), and hot air‐drying (HD). The moisture content, oil content, L*, b*, and index of ...

    • Natural occurrence of Fusarium and subsequent fumonisin contamination in preharvest and stored maize in Benin, West Africa 

      Fandohan, P.; Gnonlonfin, B.; Hell, K.; Marasas, W.F.O.; Wingfield, M.J. (2005-03-15)
      The natural occurrence of Fusarium and fumonisin contamination was evaluated from 1999 to 2003 in both preharvest and stored maize produced by small-scale farmers in four agroecological zones of Benin. Mycological analyses revealed a predominance of both Fusarium and Aspergillus in maize samples compared to other genera. The two Fusarium species most commonly isolated from maize were Fusarium verticillioides (68%) and Fusarium proliferatum (31%). Atypical isolates of F. verticillioides with some ...

    • Cannibalism and interspecific predation in a phytoseiid predator guild from cassava fields in Africa: evidence from the laboratory 

      Zannou, I.D.; Hanna, R.; Moraes, G.J. de; Kreiter, S. (2005-10)
      Interspecific predation and cannibalism are common types of interaction in phytoseiid predator guilds, but the extent and nature of these interactions have not been determined yet in phytoseiid guilds composed of African native and neotropical exotic phytoseiid predators found in cassava habitat in southern Africa. We determined in laboratory experiments the level of cannibalism and interspecific predation among the three phytoseiid mite species Euseius fustis, Iphiseius degenerans, and Typhlodromalus ...

    • Screening maize for drought tolerance in the Guinea savanna of West and Central Africa 

      Badu-Apraku, B.; Fakorede, M.A.B.; Menkir, A.; Kamara, A.; Dapaah, S. (2005)
      Full-sib families derived from Pool 16 DT, a tropical maize ( Zea mays L.) population, were evaluated in the 1995/96 and 1997/98 dry seasons, using two sites each season in Côte d’Ivoire. In all sites, the crop was irrigated from planting to about 2 weeks before anthesis, irrigation was discontinued thereafter for the rest of the season in one site in 1995 and both sites in 1997. Irrigation was continued till maturity in the second site in 1995. The means and ranges showed that the induced stress ...

    • Efficacy and costs of handheld sprayers in the subhumid savanna for cogongrass control 

      Nielsen, O.K.; Chikoye, D.; Streibig, J.C. (2005-09)
      Cogongrass continues to be one of the most invasive weeds in the subhumid savanna. Herbicide application expenses depend on equipment costs, costs of water transport for spraying, and chemical costs. In three on-farm experiments on land heavily infested with cogongrass, the effectiveness of a knapsack sprayer (KS), a very low volume sprayer (VLV), and a rope wick (RW) applicator was tested at Ijaye, Nigeria, from 2000 to 2001. The sprayers differed in application method, price, and carrier volume ...

    • Biological control of three floating water weeds, Eichhornia crassipes, Pistia stratiotes, and Salvinia molesta in the Republic of Congo 

      Mbati, G.; Neuenschwander, P. (2005-08)
      Since 1999, four specific weevils (Coleoptera, Curculionidae) were released in the Republic of Congo against three exotic floating water weeds: Neochetina eichhorniae Warner and N. bruchi Hustache against water hyacinth, Neohydronomus affinis Hustache against water lettuce, and Cyrtobagous salviniae Calder and Sands against water fern. Recoveries of exotic weevils were made from all 24 release sites except one, and all four species have established and spread (up to 800 km for water hyacinth ...

    • The effects of artificial selection on the maize genome 

      Wright, S.I.; Bi, I.V.; Schroeder, S.G.; Yamasaki, M.; Doebley, J.F.; McMullen, M.D.; Gaut, B.S. (2005-05-27)
      Domestication promotes rapid phenotypic evolution through artificial selection. We investigated the genetic history by which the wild grass teosinte (Zea mays ssp. parviglumis) was domesticated into modern maize (Z. mays ssp. mays). Analysis of single-nucleotide polymorphisms in 774 genes indicates that 2 to 4% of these genes experienced artificial selection. The remaining genes retain evidence of a population bottleneck associated with domestication. Candidate selected genes with putative function ...