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Journal and Journal Articles: Recent submissions
Now showing items 1581-1600 of 5157
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Factors affecting the adoption of fertilizers by rice farmers in Cote dIvoire
(1996)This paper analyzed the factors that affect the adoption of chemical fertilizers by rice farmers in Côte d'lvoire using a Tobit model. The results show that the major factors that positively influence farmers' use of fertilizers in rice fields are cultivation of lowlands, use of mechanization, farm size, land pressure and availability of non-farm income. Factors found to negatively affect the use of fertilizer in rice fields are the distance of the field to the village, distance of the village to ... -
A land management based approach to integrated Striga hermonthica control in subSaharan Africa
(1996)Striga hermonthica, an obligate root parasite of grasses, is one of the most severe constraints to cereal production in sub-Saharan Africa. In the recent past, prior to increased production pressure on land, S. hermonthica was controlled in African farming systems by prolonged crop rotations with bush fallow. Because of increasing need for food and concomitant changes in land management practices, however, these fallow rotations are no longer extensively used. Shorter crop rotations and fallow ... -
Effect of some food sources associated with cassava in Africa on development success, fecundity, and longevity of Euseius fustis (Pritchard and Baker) (Acari: Phytoseiidae)
(1996)Various foods associated with cassava were tested for their effect on the development, fecundity and longevity of Euseius fustis, the most common phytoseiid species found on cassava in Africa. Euseius Justis developed successfully to adulthood on the spider mite prey species Mononychellus tanajoa (Bondar) and Oligonychus gossypii (Zacher) and on pollen from maize, castor bean and cassava. Euseius Justis also completed development on water-diluted phloem exudate from cassava, diluted honeydew from ... -
Competition between Gyranusoidea tebygi and Anagyrus mangicola, parasitoids of the mango mealybug, Rastrococcus invadens: interspecific host discrimination and larval competition
(1996)The competition between Gyranusoidea tebygi Noyes and Anagyrus mangicola Noyes (both Hymenoptera: Encyrtidae), exotic parasitoids of the mango mealybug, Rastrococcus invadens Williams (Homoptera: Pseudococcidae) was studied in the laboratory. No significant differences were found in the way each parasitoid species examined, attacked, stung, and oviposited into hosts, unparasitized, or previously parasitized by the other species. This suggests that neither species discriminates against each other. ... -
Effect of the black sigatoka resistance locus bs1 and ploidy level on fruit and bunch traits of plantain-banana hybrids
(1996)Plantain (Musa spp., AAB group) cultivation is threatened by black sigatoka, an airborne fungal (Mycosphaerella jijiensis Morelet) leaf spot disease. Several traits in plantains and bananas are mainly affected by major genes. The host resistance response to black sigatoka is under the control of at least three different genes, one major recessive gene bSI and two other independent additive alleles. Diploid and tetraploid plantain hybrids were evaluated for bunch weight, fruit weight, fruit length ... -
Mycotoxins in foods in Africa
(1996) -
Resistance to the legume pod borer, Maruca vitrata Fabricius and the probable modalities involve in wild Vigna
(1996)A large number of accessions belonging to selected wild Vigna species namely V. unguiculata subspecies dekindtiana, V. oblongifolia, and V. vexillata were evaluated using choice (DCAT) and no-choice (NCFT) laboratory feeding bioassays to determine their resistance to the pod borer, Maruca vitrata Fabricius. The most resistant accessions belonged to V. vexillata, followed by those from V. oblongifolia, with a few outstanding exceptions from V. unguiculata. Even though the latter were the least ... -
The effect of nitrogen on the growth and development of giant witchweed, Striga hermonthica Benth: effect on cultured germinated seedlings in host absence
(1996)For the first time in sterile nutrient media in the absence of the host plant, different forms and rates of nitrogen compounds were screened for their effect on S. hermonthica Benth. shoot development beyond seed germination. There was no shoot formation beyond the inoculation stages when S. hermonthica germlings were grown in media devoid of nitrogen source. In culture media containing some nitrogen sources, healthy shoots were formed. Increasing concentrations ofKN03, NaN03, Ca(N03h, Mg(N03h and ... -
Variation in the genome of rice tungro bacilliform virus: molecular characterization of six isolates
(1996)The DNA genomes of isolates of rice tungro bacilliform virus from Bangladesh, India, Indonesia, Malaysia and Thailand were cloned and compared with that of the type isolate from the Philippines. Restriction endonuclease maps revealed differences between the isolates and cross-hybridization showed that they fell into two groups, those from the Indian subcontinent and those from south-east Asian countries. The genomes of isolates from the Indian subcontinent contained a deletion of 64 bp when compared ... -
Some biological and genomic properties of rice tungro bacilliform badnavirus and rice tungro spherical waikavirus from Nepal
(1996)A survey of rice fields during the main growing seasons in 81 locations from 21 districts of the southern Terai region of Nepal indicated that rice tungro was primarily restricted to the Hardinath (Janakpur) and (Parwanipur (Bara) regions. The tungro incidence in Hardinath ranged from 17% to 51% and in Parwanipur from 6% -61% causing about 89% grain yield loss in Hardinath. Both rice tungro bacilliform badnavirus RTBV) and rice tungro spherical picornavirus(RTSV) were found in tungro isolates ... -
Control of Zonocerus variegatus with ULV formulation of Metarhizium flavoviride conidia
(1996)An oil-based formulation of Metarhizium flavoviride conidia, applied at 2 1012 spores ha-1 in 1 l ha-1 gave good control of Zonocerus variegatus in 1-ha plots in southern Benin. In a three-replicate, randomized, complete block (RCB) trial in Mono province, a significant reduction in insect counts between treated and control plots was observed 10-15 days after application; treatment reduced the population by about 90%. A four-replicate RCB trial in Oue me province also gave high mortality. Although ... -
Apparent male fertility in Musa germplasm
(1996)Current efforts to produce improved genotypes of plantain and banana (Musa spp.) depend on crossing female-fertile clones with accessions that produce viable pollen. Musa accessions (168) were screened for production of viable pollen based on staining with acetocarmine glycerol jelly. Diploid hybrids and landraces produced significantly more pollen than triploids and tetraploids, suggesting more successful crosses when using diploid accessions as male parents. There was a positive correlation ... -
Combining ability of tropical maize germplasm in West Africa II. Troppical vs temperate x tropical origins
(1996)Grain yield of maize (Zea mays L.) in the tropics are generally low and information on combining ability among tropical maize inbred lines has not been reported for West Africa. This study was conducted to estimate combining abilities of maize inbred lines developed for West Africa. Crosses obtained from ten inbreds including five of tropical origin (A) and five of temperate x tropical origin (B) were evaluated in three environments of forest-first and -second seasons, and the savanna. For the ... -
Leucaena + maize alley cropping in Malawi: Part 1: Effects of N, P, and leaf application on maize yields and soil properties
(1996)Yields under alley cropping might be improved if the most limiting nutrients not adequately supplied or cycled by the leaves could be added as an inorganic fertilizer supplement. Three historic leaf management strategies had been in effect for 3 years in a Leucaena leucocephala alley cropping trial on the Lilongwe Plain of central Malawi: I) leaves returned; 2) leaves removed; and 3) leaves removed, with 100 kg inorganic N ha-I added. An initial soil analysis showed P status to be suboptimal under ... -
Screening woody and shrub legumes for growth, nodulation and nitrogen-fixation potential in two contrasting soils
(1996)In order to identify for alley cropping new candidate species with high biomass and nitrogen-fixing potential, a screening study was conducted on ten woody and shrub legumes (Acacia auriculiJormis, Albizia lebbeck, Gliricidia sepium, Leucaena diversifolia, L. leucocephala cv. K28 and cv. K636, Lonchocarpus sericeus, Cajanus cajan, Crotalaria juncea and Tephrosia candida) for 6 months using an acid Ultisol and a non-acid Alfisol. A wide interspecific variability of legumes appeared within soil ... -
Time course of biological nitrogen fixation, nitrogen absorption and biomass accumulation in three woody legumes
(1996)In order to determine how dependent a woody legume can be upon potential N sources, the time course of N2 fixation and N absorption was studied on Gliricidia sepium cv. ILG50, Leucaena leucocephala cv. K28, and Albizia lebbeck in a screenhouse for 16 months using Senna siamea as a reference tree. Dry matter and N yield in all four species increased steadily with time. The numbers and dry weight of nodules also increased with tree age. N-difference and N dilution methods correlated well (r = ... -
Dynamics of nodulation, nitrogen fixation, nitrogen use and biomass yield over time in potgrown Leucaena leucocephala (Lam.) de Wit
(1996)The dynamics of nodulation, N2-fixation and N use in Leucaena leucocephala cv. K28 over time was investigated in a screenhouse at 4, 8, 12 and 16 months after planting (MAP) using the 15N-labelling method. Leucaena had a consistently increasing pattern of nodulation, dry biomass and nitrogen yield. A sharp rise in nodulation was observed between 12 and 16 MAP, whereas for biomass, N accumulation and N2-fixation, and N2-fixation, an upward surge occurred between 4 and 12 months. Nodulation, N ... -
Nutrient availability of earthworm casts collected from under selected woody agroforestry species
(1996)Pot experiments were carried out to assess the nutrient availability of earthworm casts (wormcasts) of Hyperiodrilus africanus that were collected from plots of Dactyladenia barteri, Leucaena leucocephala and Treculia africana grown on an Alfisol (Oxic paleustalf) as affected by drying and grinding, different periods of pre-incubation of ground wormcasts, and fertilizer application. Experiments were carried out using a double pot technique and rice (Oryza sativa) was used as test crop. Wormcasts ...
