Germination des Graines et Croissance en Pépinière et en Champ des Plantules de Detarium senegalense au Bénin

La plantation ou le semis est une méthode certaine pour asseoir rapidement sur le sol une couverture végétale de protection. L’utilisation réussie des semences ne peut être examinée sans une compréhension parfaite de leur physiologie. La présente étude sur Detarium senegalense a pour objectif de déterminer les paramètres de germination et la croissance des plants en pépinière et en champ. Les graines utilisées pour la germination ont subi plusieurs traitements. Le suivi de la croissance des plantules en pépinière et d’autres mis en champ a été effectué. Les données des paramètres de germination et de croissance ont été collectées et analysées. Les résultats ont montré que les graines de Detarium senegalense ont une forte potentialité de germination sans traitement avec un taux de germination de 76 % et un temps de latence de 20 jours. Les résultats du test de Kruskal-Wallis et d’analyse de la variance (ANOVA) ont montré que la durée de trempage des graines dans l’eau froide à température ambiante a un effet négatif sur le taux de germination des graines. En ce qui concerne le suivi de la croissance des plants, les résultats ont montré que les plants de Detarium senegalense ont un accroissement assez rapide. Les plants en pépinière ont atteint en moyenne une hauteur de 83,8 ± 2,28 cm après huit mois en pépinière. Tandis que les plants en champs quant à eux ont atteint une hauteur moyenne de 137,33± 7,08 cm. Les plants en champ ont une vigueur de croissance assez élevée que les plants en pépinière. Detarium senegalense a l’aptitude d’être utilisée dans les programmes de reboisement et de restauration des forêts dégradées après quatre mois en pépinière. Planting or sowing is a sure method for quickly placing a protective plant cover on the ground. The successful use of seeds cannot be examined without a perfect understanding of their physiology. The present study on Detarium senegalense aims to determine the parameters of germination and growth of plants in the nursery and in the field. Different treatments have been carried out on the seeds used for germination. The growth of seedlings in the nursery and other field crops was monitored. Data on germination and growth parameters were collected and analyzed. The results showed that the seeds of Detarium senegalense have a strong potential for germination without treatment with a germination rate of 76% and a standby time of 20 days. The results of the Kruskal-Wallis test and analysis of variance (ANOVA) showed that the duration of soaking the seeds in cold water at room temperature has a negative effect on the germination rate of the seeds. With regard to monitoring the growth of the plants, the results showed that the plants of Detarium senegalense have a fairly rapid growth. Nursery plants reached an average height of 83.8 ± 2.28 cm after eight months in the nursery. While the field plants have reached an average height of 137.33 ± 7.08 cm. Plants in the field have a fairly high growth vigor than plants in the nursery. Detarium senegalense hasthe ability to be used in reforestation and restoration programs for degraded forests after four months in the nursery

Socioeconomic and Ethnobotanical Importance of the Breadfruit Tree (Artocarpus Communis J. G & G. Forster) in Benin

This study aims to evaluate ethnobotanical knowledge that populations hold and income from the exploitation of the breadfruit (Artocarpus communis) in southern Benin. The data collected by interview and focus group are related to the uses of Artocarpus communis, harvest methods and the habitat of specie. The results show that A. communis is used for: food, trade, artisanal, energetic, cultural and medicinal. Local populations know the species with unequal distribution among gender (Men ID = 0.75 and IE = 0.08) and Women (ID = 0.48 and IE = 0.06); and when it comes to age (Young ID = 0.56 and IE = 0.07; Adult ID = 0.606 and IE = 0.08; Old ID = 0.75 and IE = 0.1) suggesting that people make various uses of the species. The most used plant part was the fruit (VUT=11, 87). These organs (Fruits, Flowers, Leaf), are collected either by picking or collecting, (bark) by debarking and (root) by digging. 50.51% of people surveyed collected those organs on breadfruit trees present at homes, 14.65% on those present in fields, 11.62% in the dregs and 23.23% in fallow lands. The average fruit yield of an orchard is estimated at 17 tonnes/ha, which represents an average income of about 2817 USD/individual/year

Importance socio-économique de la prune rouge (Haematostaphis barteri Hook F.) au Bénin

L’importance socio-économique de H. barteri a été étudiée au Nord-Ouest du Bénin sur la base d’enquêtes ethnobotanique et socio-économique administrées respectivement sur 230 et 100 personnes des deux sexes et choisies au hasard dans les trois groupes socioculturels majoritaires du milieu d’étude à savoir les Waaba, les Bètammaribè et les Natimba. Le modèle de COBBDOUGLAS a été utilisé pour évaluer les déterminants du profit net annuel obtenu de la vente des fruits de H. barteri. L’étude a montré que les principaux organes de l’espèce à savoir les feuilles, les racines et les écorces sont employés dans le traitement de plusieurs maladies alors que les fruits sont essentiellement utilisés comme aliment. Ces différentes formes d’utilisations de H. barteri varient d’un groupe ethnique à un autre. Le revenu moyen annuel obtenu de la vente des fruits de H. barteri est faible (10 077 FCFA) et est significativement (P < 0,001) influencé par la quantité totale de mains d’oeuvre employée et la quantité de capital total utilisée. La conservation in situ des arbres de H. barteri et la valorisation de ses fruits à travers leur transformation pourraient contribuer à la préservation future de l’espèce.© 2016 International Formulae Group. All rights reserved.Mots clés: Bénin, conservation, ethnobotanique, Haematostaphis barteri, rentabilité économiqueEnglish Title: Socio-economic importance of Blood plum (Haematostaphis barteri Hook F.) in BeninEnglish AbstractThe socioeconomic importance of H. barteri has been studied in North West Benin on the basis of ethnobotanical and socioeconomic investigations respectively administered to 230 and 100 people of both sexes and randomly selected from the three majority sociocultural groups of study area namely Waaba, Bètammaribé and Natimba. The COBB-DOUGLAS model has been used to assess the determinants of annual net profit obtained from the sale of H. barteri fruits. The study shows that the main organs of the species namely the leaves, roots and barks are used in the treatment of many diseases while fruits are mainly used as food. These different uses of H. barteri vary from one ethnic group to another. The average annual income obtained from the sale of H. barteri fruits is low (10 077 FCFA) and is significantly (P < 0.001) influenced by the total workforce and the amount of total capital used. In situ conservation of H. barteri trees and the valorization of its fruits through their transformation could contribute to the future preservation of the species.© 2016 International Formulae Group. All rights reserved.Keywords: Benin, conservation, ethnobotany, Haematostaphis barteri, economic profitabilit

Effets De l’Acide Naphtalène Acétique, Du Type De Substrat Et De La Grosseur Des Boutures Sur Le Bouturage De Tige De Pterocarpus Erinaceus Poir. (Fabaceae)

This study, conducted in south-east Benin, aims to provide practical information on the optimal conditions for successful propagation of stem cuttings of Pterocarpus erinaceus Poir. (Fabaceae), a real alternative to its regeneration and domestication. A trial was conducted to evaluate the effect of different doses of Acid Naphthalene Acetate (ANA) (0; 500; 750; 1000 and 1500 mg/l), the type of substrate (black forest sand and fine sand) and the size of the cuttings used ([1.5-2] and [2.5-3] cm of diameter) on the recovery of these cuttings. To evaluate the effect of different treatments on budding rate, bud burst rate and degenerate cuttings rate, Generalized Linear Mixed Models and Generalized Linear Models of the binomial family with the lme4 and nlme packages were used with the R.3.2.4 statistical software. The results showed that the application of ANA does not significantly improve the cuttings recovery. The probability of budding and budding with 0 mg / l of ANA is similar to that of 500 mg/l, and 750 mg/l of ANA ; doses of 1000 and 1500 mg/l of ANA significantly reduce the probability of budding and bud burst. The diameter of the stems of Pterocarpus erinaceus does not affect the recovery of the cuttings while the substrate has a marginal effect. Levels of degenerate cuttings during the trial do not vary with the treatments

Evaluation des Dégâts de Eteoryctis gemoniella (Lepidoptera: Gracillariidae) dans les Plantations d’anacardier au Bénin

The leafminer Eteoryctis gemoniella is a pest that causes damage to the cashew tree. This study accessed the damage of Eteoryctis gemoniella in the propitious areas for cashew tree in Benin. Data were collected between December and April during the agricultural campaign 2015-2016 and 2016- 2017 within 21 cashew plantations. Three age classes were considered to select the plantations sampled. The percent of cashew’s leave infested by E. gemoniella was counted in each 1 m² plots. The results showed that in 2017 the average number of plants infested was significant (6.73, p<0.05) in contrary to 2016 year (4.73). The number of leaves infested by E. gemoniella varies significantly (P <0.001) from an agro-ecological zone to another and from an age class to another. The cashew trees in agro-ecological zone 5 were most infested by E. gemoniella. 20% of plants were infested in this agroecological zone in contrary to the agro-ecological zone 3 with 16% plants infested. The majority of farmers surveyed (92.67%) perceived that the damage from E. gemoniella is low. Despite that the damage caused by E. gemoniella is low, it is important to warn the actors of the sector so that preventive measures are taken to avoid, in the future, thresholds of nuisance economically disastrous. La mineuse de feuille Eteoryctis gemoniella est l’un des ravageurs qui crée des dommages à l’anacardier. L’objectif de la présente étude est d’évaluer les dégâts de Eteoryctis gemoniella dans les zones favorables de l’anacardier au Bénin. Les données ont été collectées de Décembre à Avril au cours des campagnes 2015-2016 et 2016-2017 dans 21 plantations d’anacardier. Trois classes d’âge ont été prises en compte dans le choix des plantations. Dans les quadrants de 1 m², le pourcentage de feuilles infestées par E. gemoniella a été déterminé par comptage et rapporté au nombre total de feuilles dans les quadrants. Les résultats ont montré que l’année 2017 a significativement (P < 0,05) connu un nombre plus important de plants attaqués (6,73 en moyenne) par E. gemoniella comparativement à l’année 2016 (4,73 en moyenne). Le nombre de feuilles attaquées par E. gemoniella varie trèssignificativement (P<0,001) d’une zone agro-écologique à une autre et d’une classe d’âge à une autre. La zone agro-écologique 5 a été la plus attaquée par E. gemoniella. soit 20% d’attaque comparativement à la zone agro-écologique 3 qui a été la moins attaquée (16%). La majorité des producteurs enquêtés (92,67%) a perçu que les dégâts de l’insecte sont très faibles. Malgré que les dégâts soient faibles, il faut attirer l’attention des acteurs de la filière afin que des mesures préventives soient prises pour éviter à l’avenir, des seuils de nuisance économiquement désastreux

Structural Characterization of Prosopis africana

The structural characterization of Prosopis africana of Benin was studied on the basis of forest inventory conducted in three different vegetation types (savannah, fallow, and field) and three climate zones. The data collected in 139 plots of 1000 m2 each related to the diameter at breast (1.3 m above ground), total height, identification, and measurement of DBH related P. africana species height. Tree-ring parameters such as Blackman and Green indices, basal area, average diameter, height of Lorey, and density were calculated and interpreted. Dendrometric settings of vegetation type and climate zone (Guinea, Sudan-Guinea, and Sudan) were compared through analysis of variance (ANOVA). There is a significant difference in dendrometric settings according to the type of vegetation and climate zone. Basal area, density, and average diameter are, respectively, 4.47 m2/ha, 34.95 stems/ha, and 37.02 cm in the fields; 3.01 m2/ha, 34.74 stems/ha, and 33.66 cm in fallows; 3.31 m2/ha, 52.39 stems/ha, and 29.61 cm in the savannahs. The diameter distribution and height observed at the theoretical Weibull distribution show that the diameter and height of the populations of the species are present in all positively skewed distributions or asymmetric left, a characteristic of single-species stands with predominance of young individuals or small diameters or heights

Challenges of Conservation and Sustainable Management of African Rosewood (<em>Pterocarpus</em><em>erinaceus</em>) in West Africa

Pterocarpus erinaceus is an endemic and threatened plant species in arid and semiarid zones of West Africa and is highly exploited for timber, animal feeding, and various medicinal uses. The species is currently native to the Guinean forest-savannah mosaic ecoregion and reported from Senegal to Cameroon. The values of the main characteristics of the P. erinaceus forest stands (density, average diameter, average height and average stem height) vary significantly (P < 10−3) from the Guinean zone to the Sahelian zone. It has high technological performance and can be classified as heavy and very hard wood with a density of the order of 0.80 ± 0.07 g/cm3 and an average hardness of 12 ± 3.7 g/cm3. The species is the subject of large-scale international traffic between West Africa and Asia, which is by far the greatest threat to the species. The various uses induce repeated mutilation and increase pressures on the species resulting in a significant reduction in its natural populations. In response to this situation, measures are proposed, including large-scale plant production strategies, the definition of minimum felling diameters, policy measures, etc., to meet the restoration needs of natural stands of P. erinaceus and the fight against climate change

Morphological Variation and Ecological Structure of Iroko ( Milicia excelsa

Iroko (Milicia excelsa) is a commercially important timber tree species formerly known by local people in Benin. Because of the highly attractive technological properties of its wood and its multipurpose uses, the species was subjected to intensive human pressure. Apart from strong climate oscillation during the Pleistocene, human caused habitat fragmentation through continuous land clearing for agriculture, extensive forests exploitation and urbanization induced the occurrence of many isolated forest plots and trees species among which Milicia excelsa trees. As fragmentation was proved to have deleterious effects on genetic diversity within a species and its morphological structure, it was of interest to investigate the current demographic, morphological and genetic structure of M. excelsa before coming up with conservation strategies. In the current study, morphological variation and ecological structure of M. excelsa populations were assessed in Benin using transect sampling method and multivariate analyses including principal component, cluster and canonical discriminant analyses. On the basis of morphological parameters, M. excelsa individuals and populations were clustered into four and discrimination of groups indicated that most of variations were highly related to edaphic factors and annual rainfall. Erratic diameter distribution was found for many populations although most of them showed bell shaped diameter distribution

Facteurs déterminants de la fragmentation du bloc forêt classée-forêts sacrées au Sud-Bénin

Objectif: La présente étude vise à (i) identifier les types de groupement végétaux à l’origine de la création des forêts sacrées suivant la structuration de Juhe-Beaulaton (2006), (2) décrire les périodes probables de sacralisation des forêts sacrées et (3) analyser les déterminants de la nucléarisation des forêts sacrées.Méthodologie et résultats. Alors que les connaissances actuelles sur la fragmentation des massifs forestiers de la région proviennent surtout d’études botaniques, palynologiques et archéologiques, la présente étude identifie à partir des perceptions des populations riveraines des forêts sacrées, les facteurs déterminants la fragmentation d’un bloc forestier afin de proposer des stratégies d’aménagement et de gestion durable en tenant compte des considérations culturelles et cultuelles. Des discussions de groupes et des enquêtes individuelles menés auprès de 120 personnes âgées riveraines des forêts sacrées ont permis de documenter leurs origines, les périodes et les raisons de sacralisation de ces forêts, les pratiques de gestion instituées, les perceptions sur la régression et ses causes, et les facteurs ayant favorisé la conservation de celles qui ont persistés. Il ressort des analyses que la majorité des forêts sacrées proviennent soit de massifs préexistants, soit de bois sacrés ou de sites historiques. Leur sacralisation s’était réalisée de pair avec l’installation des peuplements humains dans les zones forestières, surtout avant et pendant la période coloniale. La sacralisation des forêts reposant sur des interdits cultuels a renforcé leur conservation mais n’a pas empêché la régression de la superficie de la quasi totalité des massifs sacralisés. Aussi, la colonisation, l’orientation politique du Bénin et la poussée démographique sont apparues comme les facteurs aux effets prédominants et additifs dans cette régression des forêts, même après leur sacralisation.Conclusion et application des résultats. On retient que si la sacralisation des reliques forestières est souvent reconnue comme une solution indigène pionnière pour la sauvegarde du patrimoine forestier, le maintien d’un tissu social cohérent avec les valeurs endogènes qui sous-tendent la gestion des massifs est nécessaire pour la persistance de ce bénéfice. La stratégie de conservation et d’utilisation durable des forêts sacrées doit être inclusive au niveau local avec un renforcement de l’autorité traditionnelle dans la gestion et la dotation des forêts sacrées d’outil juridico-technique de gestion.Mots clés: fragmentation des forêts, déterminant, perceptions locales, valeurs endogènes, sud-BéninEnglish Title: Determinant factors of forests’ fragmentation: a case study of the sacred forests in South BeninEnglish AbstractObjective: The current study aimed at (1) identifying vegetation groups at origin of sacred groves creation using Juhe-Beaulaton (2006) approach (2) describe sacred groves creation periods and (3) analyze factors expressing their dynamic.Methodology and results: While current body of knowledge on forest fragmentation come from botanical, palynological and archaeological studies, this study seeks to identify from perceptions of riverine people of sacred groves, factors responsible of forest block fragmentation in order to propose their sustainable management and reclamation taking into account cultural considerations. Group and individual interviews were done with 120 old people. Data was collected on riverine to sacred groves documentation, their origin, period and reason of making them sacred groves, management practices, perceptions on forest decline and underlying causes and factors that have allowed conservation of persistent sacred groves. Results showed that most of the sacred groves originated from pre-existing large forests, trees made sacred or from historical sites. Their “consecration” took place at same time with human settlement in forest areas, especially before and in the colonial period. The “consecration” of the forests reinforced its conservation but did not prevent the regression of the area of almost all the sacred groves. In addition, colonization, political orientation of Benin and population growth appeared as factors with predominant and additive effects on forest regression, even after they had been made sacred.Conclusion and application of results: Even if “consecration ” of forest relic is often recognized as an endogenous solution to safeguard forest resources, the maintenance of social order along with endogenous values that sustain management of forest is necessary for persistent beneficial from those forests. That is why, the conservation strategy and sustainable use of sacred groves must be inclusive at the local level with a strengthening of traditional authority in the management and allocation of the sacred groves, a legal- technical management tools.Keywords: forest fragmentation, determinants, local perceptions, endogenous value

Genetic Diversity and Population Structure of a Threatened African Tree Species, Milicia excelsa, Using Nuclear Microsatellites DNA Markers

To accurately estimate the genetic diversity and population structure for improved conservation planning of Milicia excelsa tree, 212 individuals from twelve population samples covering the species' range in Benin were surveyed at seven specific microsatellite DNA loci. All loci were variable, with the mean number of alleles per locus ranging from 5.86 to 7.69. Considerable genetic variability was detected for all populations at the seven loci (AR=4.60; HE=0.811). Moderate but statistically significant genetic differentiation was found among populations considering both FST (0.112) and RST (0.342). All of the populations showed heterozygosity deficits in test of Hardy-Weinberg Equilibrium and significantly positive FIS values due to inbreeding occurring in the species. Pairwise FST values were positively and significantly correlated with geographical distances (r=0.432; P=.007, Mantel's test) indicating that populations are differentiated by “isolation by distance.” Bayesian analysis of population structure showed division of the genetic variation into four clusters revealing the existence of heterogeneity in population genetic structure. Altogether, these results indicate that genetic variation in Milicia excelsa is geographically structured. Information gained from this study also emphasized the need for in situ conservation of the relict populations and establishment of gene flow corridors through agroforestry systems for interconnecting these remnant populations