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Roger R.B. Leakey Zacharie Tchoundjeu Rognvald I. Smith Robert C. Munro Jean-Marie Fondoun Joseph Kengue Paul O. Anegbeh Alain R. Atangana Annabelle N. Waruhiu Ebenezer Asaah Cecilia Usoro Victoria Ukafor 《Agroforestry Systems》2004,60(2):101-111
Ten fruit and kernel traits were measured in 152 Irvingia gabonensis and 293 Dacryodes edulis trees from 6 villages in Cameroon and Nigeria. Frequency distribution curves were used to examine the range of variation
of each trait of each species in each village and aggregated into national and regional populations. There were differences
between the village sub-populations, with regard to the normality (e.g., mean kernel mass of D. edulis) or skewness (e.g., mean flesh depth of D. edulis) of the distribution curves and in the degree of separation between the individual village populations along the x axis,
resulting in the development of a bimodal distribution in the regional population. For all traits, populations of both species
differed significantly between countries, but only in D. edulis were there significant differences between the Cameroon populations. On the basis of the results of this study, D. edulis can be said to be virtually wild in Nigeria but semi-domesticated in Cameroon, while I. gabonensis is wild in Cameroon and semi-domesticated in Nigeria. These results are discussed with regard to a hypothesis that the range
and frequency of variation in the different populations can be used to identify five stages of domestication. From a comparison
of the frequency distribution curves of desirable versus undesirable traits, and statistically identifyable changes in skewness and kurtosis, it is concluded that as a result of
the farmers’ own efforts by truncated selection, D. edulis is between Stages 2 and 3 of domestication (with a 67% relative gain in flesh depth) in Cameroon, while I. gabonensis in Nigeria is at Stage 2 (with a 44% relative gain in flesh depth). In this study, genetic diversity seems to have been increased,
and not reduced, by domestication.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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Ann Degrande Patrick Tadjo Bertin Takoutsing Ebenezar Asaah Alain Tsobeng Zac Tchoundjeu 《Small-Scale Forestry》2013,12(3):403-420
Availability of high quality tree planting material within proximity of farmers and at affordable prices is one of the prerequisites for larger uptake of tree cultivation. This study examines whether rural small-scale nurseries can produce a diversity of tree planting material and whether resource-poor farmers have access to it. Twelve nurseries supported by the tree domestication program in the West and North-west regions of Cameroon were compared to 12 nurseries in similar conditions, but not in contact with the program. Nurseries using the domestication approach were found to provide tree planting material that responds better to farmers’ needs in terms of quantities, species and propagation methods used. Their clientele is more diverse including farmers from the communities where the nurseries are located, but also from far beyond. However, prices of vegetatively propagated material were considered the most prohibitive factor. It is concluded that tree planting initiatives should refocus efforts towards technical training and business support to small-scale nurseries to increase efficiency. Research efforts should look for ways of reducing production costs and improving nursery productivity. 相似文献
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Bertin Takoutsing Zacharie Tchoundjeu Ann Degrande Ebenezar Asaah Amos Gyau Frederick Nkeumoe Alain Tsobeng 《Small-Scale Forestry》2014,13(1):65-77
In developing countries seedlings are often produced in small-scale nurseries as a means to raise tree planting materials and, provided they are of high quality, these can form the basis for successful forest plantation initiatives. This study uses morphological characteristics to assess the quality of seedlings of three tree species (Persea americana, Cola acuminata and Dacryodes edulis) in the Western Highlands of Cameroon. The growth characteristics and quality indicators of seedlings produced in two nursery categories were compared—three nurseries collaborating with the tree domestication program implemented by the World Agroforestry Centre (Category 1) and three nurseries collaborating with government and non-governmental projects (Category 2). Seedlings produced in nurseries in the first nursery category were found to be uniform in terms of growth characteristics and quality indicators. In the second category, there were relatively higher seedling proportions having measured parameters out of threshold standards for root to shoot ratio and for sturdiness quotient. Significant differences between nursery categories (at α = 0.05) were detected in root collar diameter of C. acuminata and D. edulis and in shoot dry weight of D. edulis. These differences could be attributed to better nursery management as a results of training and technical backstopping received by nursery operators in Category 1. The level of experience of nursery operators in both categories was found to be insufficient and greater exposure to skills and knowledge could enhance the production of high quality seedlings. 相似文献
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Divine Foundjem-Tita Zac Tchoundjeu Stijn Speelman Marijke D’Haese Ann Degrande Ebenezer Asaah Guido van Huylenbroeck Patrick van Damme Ousseynou Ndoye 《Small-Scale Forestry》2013,12(3):489-505
Agroforestry and planting trees on farmers’ fields have been reported as important elements in a strategy to meet the millennium development goals of poverty reduction and climate change improvement. However, their uptake seems to be constrained by factors both internal and external to the household and related to the policy and legislative environment. This paper examines the impact of these factors on farmers’ decisions to plant trees. Cameroon is used as a case to analyse whether existing policies and legislation governing trees support or discourage tree planting, using qualitative content analyses. Although their mission papers and statements suggest most national government policies in Cameroon address tree planting and agroforestry, actual legislation designed to follow up the policies mostly contradicts the poverty reduction goals. Often legislation and regulations are more conservation-oriented and do not provide a clear procedure to distinguish between products from trees found in the wild and those gathered from farmers’ fields. 相似文献
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Alain Tsobeng Ebenezar Asaah Roger Leakey Zacharie Tchoundjeu Van Damme Patrick Daniel Ofori Ramni Jamnadass 《New Forests》2019,50(3):505-517
New Forests - The rooting of Allanblackia stem cuttings is typically slow and with the formation of very few roots. Irradiance has positive effects on the relative growth of plants and rooting... 相似文献
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A. R. Atangana Z. Tchoundjeu J-M. Fondoun E. Asaah M. Ndoumbe R. R. B. Leakey 《Agroforestry Systems》2001,53(1):55-64
Twenty four fruits from each of 52 Irvingia gabonensis trees from two villages (Nko'ovos II and Elig Nkouma) of the humid lowland forest zone of Cameroon (West Africa) were assessed to determine the extent of variation in ten fruit, nut (endocarp), and kernel (cotyledon) characteristics. Highly significant differences were found in fruit length (Range = 46.2 to 77.3 mm), fruit width (45.1 to 72.5 mm), flesh (mesocarp) depth (11.2 to 21.8 mm), fruit mass (44.5 to 195.4 g), kernel mass (0.54 to 6.9 g) and shell mass (5.4 to 18.6 g). In each of these traits there was continuous variation. Differences were also observed in fruit taste and fibrosity. The most frequent skin and flesh color was yellow (Methuen Color Code 4A8). Mean fruit length, fruit width, fruit mass, shell mass and kernel mass differed significantly between villages, but did not differ between different landuses (homegardens, cocoa farms, crop fields or fallows). These results represent the first quantitative assessment of tree-to-tree variation in fruit traits for this species and are discussed with regard to the domestication potential of I. gabonensis.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
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Soil moisture depletion during dry seasons by planted hedgerows to lower levels than under natural fallow, would reduce drainage
and nutrient losses in the following rainy season when food crops are grown. The volumetric water content of the 0–150 cm
soil profile was measured under planted hedgerows (alternating Leucaena leucocephala and Gliricidia sepium) and natural fallow, both either annually cropped to sole maize or in a two-year crop/two-year fallow rotation, in the humid
forest zone (annual rainfall 1700 mm) of southern Cameroon during the 1995–1996 and 1996–1997 dry seasons. Hedgerows were
cut to 0.05 m height, largely eliminating trees’ water consumption during cropping phases. Differences in total soil water
content at 0–150 cm depth, between systems, occurred only in the early phases of the 1996–1997 dry season. In both dry seasons,
differences between systems in water content were found in some soil layers, all within 0–60 cm depth, yet, without consistent
advantage of any system in exploiting the topsoil water resources. Soil water content was lower under L. leucocephala than G. sepium at 20–40 cm depth only. Below 60 cm depth, no differences in water regimes between systems were found. Under southern Cameroonian
conditions it is unlikely that any of the systems has an advantage in accessing or recovering water and thus, if available,
nutrients from the sub-soil. None of the systems examined was capable of delaying drainage and thus it appears unlikely that
downward displacement of nutrients is delayed after the start of the rains. 相似文献
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Emily Kimathi Elfatih M. Abdel-Rahman Catherine Lukhoba Asaah Ndambi Bester Tawona Mudereri Saliou Niassy Henri E. Z. Tonnang Tobias Landmann 《Weed Research》2023,63(1):45-56
Striga hermonthica (Del.) Benth is a parasitic weed that is damaging major cereal crops in sub-Saharan Africa (SSA). Although Striga is recognised as an agricultural scourge, there is limited information available indicating the extent of its growth and spread as impacted by the changing climate in Kenya. This study investigated the impact of current climate conditions and projected future (2050) climate change on the infestation of Striga hermonthica in the western Kenya region. Specifically, the study aimed to predict Striga hermonthica habitat suitability in five counties in the western Kenya region through using the maximum entropy (MaxEnt) model and bioclimatic, soil, topographic and land use, and land cover (LULC) variables. Striga hermonthica geolocations were collected and collated and ecological niche models were developed to determine the habitat suitability. The results showed that approximately 1767 km2 (10% of the total study area) is currently highly suitable for Striga hermonthica occurrence. The future projections showed a range between 2106 km2 (19% of the total study area) and 2712 km2 (53% of the total study area) at the minimum carbon (RCP 2.6) and the maximum carbon emission scenarios (RCP 8.5) respectively. Elevation, annual precipitation, LULC, temperature seasonality and soil type were determined to be the most influential ecological predictor variables for Striga hermonthica establishment. The study revealed the importance of using climate, soil, topographic and LULC variables when evaluating agricultural production constraints such as Striga's prevalence. The methodology used in this study should be tested in other Striga affected areas. 相似文献
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Ebenezar Asaah Zac Tchoundjeu William Ngahane Alain Tsobeng Lazare Kouodiekong Ramni Jamnadass Anthony Simons 《New Forests》2011,41(3):389-398
Three Allanblackia species (A. floribunda, A. stuhlmannii and A. parviflora) with high nutritive, medicinal, cosmetic and economic values are currently being domesticated as new oil tree crops. Allanblackia seeds contain a hard white fat consisting mostly of stearic (52–58%) and oleic (39–49%) acids. This unusual fatty acid content
has the right properties for many different food and cosmetic products making them commercially interesting. Vegetative propagation
studies on A. floribunda, which grows naturally in the moist forest of Cameroon and Nigeria, were initiated aimed at evaluating its amenability to
grafting. Scions were grafted onto 18 month old rootstocks of A. floribunda using side tongue, top cleft, side veneer, whip-and-tongue methods under nursery conditions in Cameroon. In parallel, side
tongue and inverted ‘T’ budding methods were also tested in situ on young A. floribunda wildings growing under semi-deciduous and evergreen tree covers. In addition, the effects of protecting side tongue new grafts
with non perforated translucent plastic, perforated translucent plastic and aluminium foil were assessed. Under nursery conditions,
side tongue grafts were significantly more successful (80.0 ± 6.3%), than grafts of side veneer (52.5 ± 7.9%), top cleft (55.0 ± 7.9%)
and whip and tongue (50.0 ± 7.9%). The success of side tongue graft was further increased (86.7 ± 6.2%) under the shade of
evergreen trees when protected by non perforated translucent plastic. These results indicate the potential for in situ grafting
and ‘top working’ to promote cultivation of more productive germplasm of Allanblackia within multifunctional agricultural systems. 相似文献