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Journal and Journal Articles: Recent submissions
Now showing items 2061-2080 of 5273
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Simulation model for maize crop growth based on acquisition and allocation processes for carbohydrate and nitrogen
(1999)A population model for maize growth and development driven by temperature, solar radiation, soil water and soil nitrogen is presented. A time-varying distributed delay model is used to describe the dynamics of the attributes number, biomass and nitrogen belonging to leaf, root, stem, grain, rachys and husk populations. Photosynthate production as well as water and nitrogen acquisition was simulated with a demand-driven ratio-dependent functional response model. Carbohydrate, water and nitrogen ... -
Dependency of promiscuous soybean and herbaceous legumes on arbuscular mycorrhizal fungi and their response to bradyrhizobial inoculation in low P soils
(1999)As the production of grain and herbaceous legumes is often limited by low levels of available P in moist savanna soils, the potential for managing arbuscular mycorrhizal fungi (AMF) by selecting lines or accessions dependent on AMF as a strategy to improve plant P nutrition and productivity is required. The interactions between AMF and Bradyrhizobia sp. and their effects on growth and mycorrhizal colonization of ten recent selections of promiscuous soybean breeding lines and two herbaceous legumes ... -
Studies on predation of Prostephanus truncatus (Horn) (Col., Bostrichidae) and Sitophilus zeamais Mots. (Col., Curculionidae) at different densities on maize by Teretriosoma nigrescens Lewis (Col., Histeridae)
(1999)Laboratory experiments using whole cobs were conducted to examine the effect of varying densities of the larger grain borer, Prostephanus truncatus and the maize weevil, Sitophilus zeamais on rate of population increase by the histerid beetle, Teretriosoma nigrescens, a predator primarily of P. truncatus. Densities of all species of insects were determined at the end of the experiment, and an electrophoretic analysis of gut content was conducted on larval and adult T. nigrescens sampled during the ... -
Population simulation model of Sitophilus zeamais (Coleoptera: Curculionidae) in grain stores in West Africa
(1999)The biology of Sitophilus zeamais Motschulsky, an important pest of stored commodities, is well described in the literature. To integrate current knowledge and to understand better the population dynamics of this species in rural maize, Zea mays L., stores, we developed a distributed-delay, demographic simulation model. Published equations describing the effects of temperature, humidity, and density effects on fecundity, juvenile survivorship and development and emigration were used or equations ... -
Two mechanisms of drought tolerance in cowpea
(1999)Twelve cowpea (Vigna unguiculata) varieties were planted in wooden boxes of 130 cm length, 65 cm width, and 15 cm depth filled with sand and soil mixture (1:1) at 10 cm row to row and 5 cm plant-to-plant distances. The boxes were watered daily until the unifoliate leaves had fully expanded and the first trifoliates were beginning to emerge. Watering was then stopped to impose moisture stress, and effects of drought on the unifoliate and trifoliate leaves as well as growing tips were studied. Two ... -
Development of strategies for the incorporation of microbial pesticides into the integrated management of migratory pests
(1999)1 Effective biological pesticides based on oil formulation of deuteromycete fungal spores have been developed for use against locusts and grasshoppers. The isolate IMI 330189 of Metarhizium anisopliae (¯avoviride) var. acridum has been registered, extensively ®eld tested and its operating characteristics explored. It should form an powerful component technology in the integrated management of locust and grasshopper pests. 2 The particular advantages of Metarhizium anisopliae were found to be ef®cacy ... -
Geographic variation in growing season rainfall
(1999)Reports of changes in the seasonal and annual rainfall in Nigeria suggests that a more detailed analyses of the geographic extent of these changes and of their impact on agriculture could be of value. Variation in the growing season (April to September) rainfall from stations across Nigeria was analysed over the 30-yr period, 1960–90. Regression analyses were used to examine long-term trends. Principal component and cluster analyses were used to group stations with similar trends in standardised ... -
Cassava Manihot esculenta Crantz growth indices, root yield and its components in upland and inland valley agroecologies of Sierra Leone
(1999)Cassava is predominantly an upland crop that is also cultivated in inland valley swamps (IVS). Identifying physiological traits that can withstand excess moisture stress can aid in the selection and use of stable cassava cultivars in IVS. Three cassava cultivars were evaluated for growth and yield in the upland and IVS ecologies in the 1993–94 crop seasons using a randomized complete block design. In the upland, 80/40 outyielded 87/29 and ‘coco', while in the IVS, 87/29 had the highest yield. ... -
Differences in the effects of temperature and photoperiod on progress to flowering among diverse Mucuna spp
(1999)The use of Mucuna spp. in cover crop and green manure technologies is proving to be successful in the tropics and subtropics following intensive efforts in technology transfer to farmers by NGOs (Non‐Governmental Organizations). This includes the transfer of seeds of Mucuna spp. for which the range of adaptation and the effect of environment on crop phenology are poorly understood. A selection of Mucuna spp. germplasm was evaluated over a range of contrasting photothermal conditions in ... -
Alley cropping in the moist savanna of West Africa I. Restoration and maintenance of soil fertility on terre de barre soils in Benin Republic
(1999)The potential of alley cropping systems supplied with a limited amount of fertilizer to restore crop productivity on a degraded site and to maintain crop productivity on a recently cleared, non-degraded site on ‘terre de barre' soils in Southern Bénin was investigated from 1994 to 1996. Leucaena leucocephala, Senna siamea and Gliricidia sepium were used as hedgerow species. Maize yields of the no-tree control plots dropped from the initial (1990) 401 kg ha–1 and 2181 kg ha–1 on the degraded and ... -
Intraspecific competition in larvae of the larger grain borer, Prostephanus truncatus (Horn) with maize grains
(1998)The effects of egg clutch size on development and survivorship of the larger grain borer, Prostephanus truncatus (Horn) (Col.: Bostrichidae) on maize were measured in the laboratory using single grains of the white maize variety, TZSR-W, at 30 ± 2°C and 70 ± 5% RH. Varying numbers of P. truncatus eggs (1, 2, 4, 8, or 16) were introduced into a hole drilled into a single maize grain. Destructive sampling was used at regular intervals to obtain data on immature developmental parameters, the location ... -
Economic evaluation of using mulch from multipurpose trees in maizebased production systems in southwestern Nigeria
(1999)Cutting and carrying of mulch from established tree plots is an alternative to in situ mulch in agroforestry systems. Through the cut-and-carry method, the undesirable e ects of tree-crop competition characterized by in situ mulching can be avoided. An economic evaluation of the cut-and-carry method of providing nutrients for maize production was carried out based on investigations in south-western Nigeria. The results showed that the use of mulch from multipurpose trees (MPTs) through the ... -
Longterm alley cropping with four hedgerow species on an Alfisol in southwestern Nigeria effect on crop performance, soil chemical properties and nematode population
(1999)A longterm alley cropping trial was undertaken on an eroded Oxic paleustalf in the forest-savanna transition zone of southwestern Nigeria from 1981–1993. Two nitrogen fixing hedgerow species (Gliricidia sepium and Leucaena leucocephala) and two non legume hedgerow species (Alchornea cordifolia and Dactyladenia barteri) were used in the trial compared to a control (with no hedgerow) treatment. Plots were sequentially cropped with maize (main season) followed by cowpea (minor season). With 4 m ... -
Weed seed bank size and composition in an arable crop mulched with pruning from three multipurpose trees in southwestern Nigeria
(1999)Weed seed bank size and composition were analysed in 1995 and 1996 in maize fields mulched with pruning from Gliricidia sepium, Leucaena leucocephala, and Senna siamea in South Western Nigeria. Plots mulched with pruning from the three trees had a lower weed seed bank in the first year of cropping than unmulched plots. In the second year of cropping, the weed seed bank was higher than in the first year in the Gliricidia sepium, and Leucaena leucocephala mulch treatments by 41 and 65% respectively. ... -
Differences in weed seed banks in planted tree fallows in southwestern Nigeria
(1999)The weed seed bank under seven fallow tree species was analysed in size and composition five years after tree establishment. The seed bank was lower in Enterolobium cyclocarpum fallows than in the other tree fallows at both 0-5 and 5-10 cm depths. Nuclea latifolia and Terminalia superba tree fallows had the highest seed banks despite the fact that they had the highest floor litter cover. There was no correlation between light transmission and seed bank suggesting that other factors than shade were ... -
Analysis of potential duplicates in barley gene bank collections using resampling of microsatellite data
(2003)Redundant duplication among putative Nordic spring barley material held at 12 gene banks worldwide was studied using 35 microsatellite primer pairs covering the entire barley genome. These microsatellite markers revealed an average of 7.1 alleles per locus, and a range of 1 to 17 different alleles per locus. Similarity of accession name was initially used to partition the 174 repatriated accessions into 36 potential duplicate groups, and one group containing 36 apparently unique or unrelated ... -
iMap: a databasedriven utility to integrate and access the genetic and physical maps of maize
(2003)Motivation: Because of the unique biological features, a bioinformatic platform for the integrated genetic and physical map of maize is required for storing, integrating, accessing and visualizing the underlying data. Results: The goal of the Maize Mapping Project is to develop a fully integrated genetic and physical map for maize. To display this integrated map, we have developed iMap. iMap has three main components: a relational database (iMapDB), a map graphic browser (iMap Viewer) and a search ... -
Relationship between dormancy and its release and external factors in tubers of water yam (Dioscorea alata L.)
(2003)To analyze the mechanism of dormancy in tubers of water yam (Dioscorea alata L.), we studied the relationship between external factors and dormancy and its release in tubers. Several strains of water yam that have been introduced into Japan from Southeast Asia and Oceania were grown in Kagoshima, Japan. Dormancy period ranging from 2 to 4 months in length (from harvest to sprouting), has been observed in 48 strains that were tested at 25 ℃. It was found that the duration of the dormancy period ... -
Breeding gains and changes in morphotypes of Nordic spring wheat (19011993) under contrasting environments
(2003)Phenotypic diversity among 75 Nordic spring wheat cultivars was assessed in a glasshouse experiment, in which plots had no fertilizer or received 14-3-23 NPK plus Mg. On average, the fertilizer application delayed flowering by one day, shortened plant height (PH), as well as enhanced the number of fertile tillers (NFT), fresh and dry straw weight (FSW and DSW, respectively), but influenced negatively the dry matter content in the straw (DMCS) and the number of kernels per spike (K/S). The ...
