Journal and Journal Articles: Recent submissions

Now showing items 1501-1520 of 5157

    • First report of southern blight caused by Sclerotium rolfsii on soybeans in Nigeria 

      Akem, C.N.; Dashiell, Kenton E. (1991)
      Southern blight of soyabeans caused by S. [Corticium] rolfsii, was observed for the first time in Nigeria, in field nurseries at Bukuru, near Jos in the Plateau State, in 1989. Over 40% of plants in plots of the cultivar TGx 1025-12E were blighted 2 weeks after the plots had been rogued to eliminate plants infected by C. rolfsii. Symptoms included yellowing, browning and wilting of entire plants. A white mat of fungal mycelia and numerous tan to brown spherical sclerotia were present on stem bases, ...

    • Weeds in human affairs in subSaharan Africa: implications for sustainable food production 

      Akobundu, I. (1991)

    • Effect of tree legumes in hedgerows on soil fertility changes and crop performance in the semiarid highlands of Rwanda 

      Balasubramanian, V.; Sekayange, L. (1991)
      The soil fertility improvement potential of five tree legumes as alley hedges was studied on a Ultic Haplustox soil at a semi-arid highland site in Rwanda from 1983 to 1989. Tree species tested were C. calothyrsus Meissn., C. spectabilis DC, L. diversifolia (Lam.) de Wit., L. leucocephala (Lam.) de Wit. and S. sesban (L.) Merr.; they grew to a height of 1.01 to 2.15 m and 2.85 to 3.37 m, after 1 and 1.5 years respectively. S. sesban could not withstand intensive pruning (four times per year) and ...

    • Effects of Gliricidia sepium (Jacq) Steud and Leucaena leucocephala (Lam.) de Wit on growth and develoment of Imperata cylindrica (L.) Reuschel 

      Anoka, U.A.; Akobundu, I.O.; Okonkwo S.N.C. (1991)
      Field studies carried out in a forest transition site on a tropical Alfisol in southwestern Nigeria, show that shading by gliricidia (Gliricidia sepium (Jacq.) Steud) and leucaena (Leucaena leucocephala (Lam.) de Wit) hedgerow species reduced density of speargrass (Imperata cylindrica (L.) Raeuschel) by 67% and 51%, respectively. Shoot biomass of speargrass decreased by 81% and 78% in gliricidia and leucaena hedgerows, respectively. Reduction in speargrass rhizome biomass in gliricidia plots was ...

    • Resistance of tropical maize inbreds to major virus and viruslike diseases 

      Brewbaker, J.L.; Kim, S.K.; Logrono, M.L. (1991)
      Tropically-adapted maize inbreds of high combining ability were evaluated internationally for general resistance to seven virus and virus-like diseases, all insect-transmitted. Replicated trials under controlled viral epibiotics were conducted at five locations as part of the collaborative Maize Inbred Resistance project. The viruses and testing sites included CS (corn stunt mollicute complex) in Mexico, MBSDV (maize black-streaked dwarf virus) in Korea, MCDV (maize chlorotic dwarf machlovirus) ...

    • Complementarity of genes for resistance to greenbug [Schizaphis graminum (Rondani)], biotype E, in sorghum [Sorghum bicolor (L.) Moench] 

      Dixon, Alfred G.O.; Bramel-Cox, P.J.; Harvet, T.L. (1991)
      Gene complementarity among various sources of resistance to greenbug biotype E was assessed. Analysis of the F2 generation of crosses between susceptible and resistant parents (mating 1) and among sources of resistance (mating 2) suggested that resistance in sorghum to greenbug biotype E was complexly inherited and, to some extent, dependent on the nature of both the resistant and susceptible parents. Positive transgressive segregation in the F2 generations of both matings was found to be due to ...

    • Yield losses in soybeans from frogeye leaf spot caused by Cercospora sojina 

      Dashiell, Kenton E.; Akem, C.N. (1991)
      Three soybean [Glycine max (L.) Merr.]cultivars (Samsoy 1, TGx 1025-12E and TGx 996-26E) were evaluated for yield losses resulting from frogeye leaf spot caused by Cercospora sojina Hara. Replicated field plots were established at two locations in Nigeria that have a high natural infestation of C. sojina. The cultivars were either not sprayed, sprayed once or sprayed twice during the growing season with the fungicide benomyl. Disease spread early in the season was from border rows of a susceptible ...

    • Effect of stem borer Eldana saccharina (Lepidoptera: Pyralidae) on the yield of maize 

      Bosque-Pérez, N.A.; Mareck, J.H. (1991)
      Field experiments were conducted in the dry season of 1985–86 and the first and second rainy seasons of 1986 at Ibadan, Nigeria, to assess the level of damage and yield reductions caused by Eldana saccharina Walker to maize. Grain weight per plant in artificially infested plots was up to 36% lower than grain weight per plant in insecticide-protected plots. Artificially infested plots had significantly lower 100-grain weight than insecticide-protected ones. The regression coefficient obtained from ...

    • Methods of onfarm, diagnostic research on adoption potential of alley cropping 

      Dvořék, K.A. (1991)
      An approach to on-farm diagnostic research on alley cropping is described. The objective of economic assessment was to evaluate the adoption potential of the technology. Three activities were included. In the first research activity, cost-route surveys and field measurements were carried out for a small sample of farmers with recently established alleys. Although research-resource intensive, the cost-route studies and field measurements were necessary to develop a framework for analyzing alley ...

    • Tillage systems for the West African semiarid tropics 

      Hulugalle, N.R.; Maurya, P.R. (1991)
      The West African Semi-Arid Tropics (WASAT) is characterized by a monomodal rainfall pattern, and based on the amount of annual rainfall it can be divided into three ecologies: Sahel, Sudan and Northern Guinea savannahs. The major soil groups of the WASAT are Alfisols, Inceptisols and Entisols and Vertisols, with the former three predominating. The major soil constraints to crop growth are: soil compaction, low fertility, high temperature and low soil water retention, available water holding capacity ...

    • Effect of cassavabased cropping systems on physicochemical properties of soil and earthworm casts in a tropical Alfisol 

      Hulugalle, N.R.; Ezuma, H.C. (1991)
      The effects of cassava-based intercropping systems and rotations on physical and chemical properties of earthworm casts and the adjacent soil were studied on an Oxic Paleustalf in south-western Nigeria. Earthworm activity was greater with intercropping although it was not significantly affected by the number of component crops in a mixture. The particle size distribution, bulk density, exchangeable cations, Bray-1-P, pH and effective cation exchange capacity (CEC) of soil and earthworm casts did ...

    • Seed populations of Striga species in Nigeria 

      Hartman, G.L.; Tanimonure, O.A. (1991)
      Seeds of Striga asiatica and S. hermonthica were separated from soil using a wet sieve method with a 2.5 smallcap˜M sucrose flotation solution and 250- and 150-µm mesh screens. In 34 fields, the av. and range of seeds/100 g of soil were 8.2 and 0-75, resp. Seeds were recovered from 28 of the 34 fields sampled. Eighteen, six and four fields had 1-5, 6-20, and >21 seeds/100 g of soil, resp. The max. number of seeds/100 g of soil was 202, collected from one sample site in a field. Emerged S. asiatica, ...

    • Some analytical aspects of cassava/maize/okra/egusimelon complex mixture: 1. Soli temperature in relation to leaf area variation 

      Ikeorgu, J.E.G.; Ezumah, H.C. (1991)
      Afternoon soil temperature of about 39°C observed at 5 cm depth under sole cassava (Manihot esculenta Crantz) early in the growing season was reduced by respectively 1.0, 1.3, 3.0 and 4.4°C by intercropping with maize (Zea mays L.), maize/okra (Abelmoschus esculentus Moench), maize/ egusi melon (Citrullus lanatus Thunb.), and maize/okra/egusi melon. There was a negative but significant relationship between soil temperature and combined leaf area index (L) of crops grown in mixture with sparse-canopy ...

    • Laboratory and screenhouse assays for evaluating cowpea resistance to the legume pod borer 

      Jackai, L.E.N. (1991)
      Two resistance screening assays were developed for evaluating cowpea Vigna unguiculata (L.) Walp resistance to the legume pod borer (MPB), Maruca testulalis Geyer, one of the most intractable pest problems of this important food crop. The first assay, the dual-choice arena test (DCAT), provided a choice of two varieties to the MPB larva for 72 h. A preference hierarchy representing the resistance ranking of test varieties was obtained using a preference ratio. The relative resistance of a given ...

    • The potential of neem, Azadirachta indica A. Juss., for controlling postflowering pests of cowpea, Vigna unguiculata Walp. Maruca testulalis, the pod borer 

      Jackai, L.E.N.; Oyediran, I.O. (1991)
      Neem oil (NO), and different formulations of neem oil in a solution of Tetrapleura tetraptera as emulsifier, including neem oil emulsifiable concentrate (NOEC), neem oil slurry emulsifiable concentrate (NOSEC) and 5% NOEC obtained from the seeds of the neem plant, were tested for their efficacy in the control of Maruca testulalis Geyer, under laboratory conditions using flowers of Ife Brown, cowpea variety.

    • Relationships between coinfection with cowpea aphidborn mosaic and cucumber mosaic viruses and yield of cowpea lines with varying resistance to these viruses 

      Mih, A.M.; Atiri, G.I.; Thottappilly, G. (1991)
      The effect of mixed infection of cowpea aphid-borne mosaic (CAMV) and cucumber mosaic (CMV) viruses on cowpea yield varied with the resistance levels of cowpea lines, since there was a strong interaction between the latter and virus infection types atP ≤ 0.01. In cowpea line TVu 3629, with low resistance to both viruses, mixed infection significantly(P ≤ 0.05) reduced most yield components as compared with single infections and uninoculated controls. However, in line TVu 15656, which is highly ...

    • Evaluating the green and Ampt infiltration parameter values for tilled and crusted soils 

      Mohamoud, Y.M. (1991)
      Methods for determining Green—Ampt infiltration parameter values for tilled and crusted soils are not well established. A two-stage method is developed to determine the Green and Ampt parameter values for soils under different management practices. The first stage is aimed at calculating rainfall infiltration from rainfall and runoff data of small field plots which had different soil surface conditions (e.g. tillage, residue cover and crusting). To determine accurate rainfall infiltration rates ...

    • A selective review of research on Prostephanus truncatus (Horn) (Col.: Bostrichidae) with an annotated and updated bibliography 

      Markham, R.H.; Wright, V.F.; Rios Ibarra, R.M. (1991)
      A review is presented of worldwide research on the stored products pest Prostephanus truncatus, with an emphasis on recent (post-1986) and previously neglected work, particularly that published in languages other than English. Topics reviewed include distribution, pest status, biology, ecology, monitoring and control. An annotated bibliography is included.

    • The need for simple dynamic equations to describe plant competition 

      Mutsears, H.J.W. (1991)
      A dynamic single-equation model for plant interaction is compared with the competition mechanism implicit in larger simulation models. When light is the limiting factor, both mechanisms can be written in the same mathematical form containing a ‘driving force’ and a restriction factor. In the single-equation model the driving force is derived directly from the RGR of a competition-free plant. In more comprehensive models, detailed information on the growth of plant organs has to be generated by ...

    • Use of successional sowing in evaluating cowpea (Vigna unguiculata) adaptation to drought in the Sudan savannah zone. 2. Responseof reproductive traits 

      Muleba, N.; Mwanke, M.; Drabo, I. (1991)
      Two sets of experiments on cowpea sowing date were conducted in 1983–85 at Ouagadougou, Burkina Faso. One set tested six daylength-insensitive (DI) cultivars and the other compared four or five daylength-sensitive (DS) cultivars with one or two DI cultivars as controls. Sowing after inadequate rainfall, particularly when followed by drought stress, impeded seedling establishment and growth. Severe drought stress during the reproductive growth stages and prolonged drought stress throughout the crop ...