19 research outputs found

    Clonal Propagation of Khaya senegalensis

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    Khaya senegalensis is a multipurpose African timber species. The development of clonal propagation could improve plantation establishment, which is currently impeded by mahogany shoot borer. To examine its potential for clonal propagation, the effects of cutting length, leaf area, stockplant maturation, auxin, and smoke solution treatments were investigated. Leafy cuttings rooted well (up to 80%) compared to leafless cuttings (0%). Cuttings taken from seedlings rooted well (at least 95%), but cuttings obtained from older trees rooted poorly (5% maximum). The rooting ability of cuttings collected from older trees was improved (16% maximum) by pollarding. Auxin application enhanced root length and the number of roots while smoke solution did not improve cuttings' rooting ability. These results indicate that juvenile K. senegalensis is amenable to clonal propagation, but further work is required to improve the rooting of cuttings from mature trees

    Régénération assistée du karité (Vitellaria paradoxa C. F. Gaertn.) dans les parcs agroforestiers au Burkina Faso

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    Le karité (Vitellaria paradoxa C. F. Gaertn.) présente une importance sociale, culturelle, économique et alimentaire pour le Burkina Faso où il occupe la quatrième place dans les produits d’exportation. La pérennité de cette espèce dont les populations rurales sont tributaires, est compromise par de multiples phénomènes dont le manque de régénération, les pratiques culturales et la coupe abusive du bois pour satisfaire les besoins énergétiques. L’objectif de cette étude est de proposer des méthodes adéquates pour rajeunir les parcs à karité au Burkina Faso. Cinq sites de recherche ont été choisis suivant un gradient phytogéographique : Sobaka, Noumoudara et Kakoumana (secteur sud soudanien), Gonsé (secteur nord soudanien) et Bouria (secteur sub sahélien). Les essais effectués dans chaque parcelle choisie, ont comporté trois répétitions et 7 traitements, représentés par les différentes techniques de régénération (plantation, transplantation, semis direct libre, semis dans les buissons, régénération naturelle assistéeRNA-, induction de drageon, induction de pousse adventive). Les résultats indiquent que le taux de survie de la régénération naturelle assistée est audessus de 70% après deux années de suivi. Les plantations et les semis directs dans les buissons sont aussi des techniques efficaces pour la régénération/restauration des parcs à karité, avec respectivement des taux de survie de 13,33% et 6,67% dans le secteur sub sahélien, 12,22% et 6% dans le nord soudanien, et 55,56% et 25,33% dans le sud soudanien après la troisième année de suivi. En conclusion, la régénération assistée est la technique la plus efficiente pour restaurer les parcs à karité. The Shea (Vitellaria paradoxa C. F. Gaertn.) is of enormous social, cultural, economic and nutritional importance for Burkina Faso where it ranks fourth in exports. The sustainability of this species on which rural populations depend is compromised by multiple phenomena, including the lack of regeneration of shea tree and the abusive cutting of wood to meet energy needs. This work aimed to propose adequate methods for rejuvenating shea parkland in Burkina Faso. Five sites distributed along a phytogeographic gradient were selected for tests : Sobaka, Noumoudara and Kakoumana (South-Sudanian phytogeographic zone), Gonsé (NorthSudanian phytogeographic zone) and Bouria (sub-Sahelian phytogeographic zone). The field trials included three repetitions by regeneration technique (planting, transplanting, direct sowing free, sowing in bushes and assisted natural regeneration -ANR-, sucker induction, induction of adventitious growth). The results indicate that the survival rate of assisted natural regeneration is above 70% after two years of follow-up. Planting and direct seeding in bushes are also effective techniques for the regeneration / restoration of shea tree parks with respectively survival rates of 13.33% and 6.67% in the sub sahelian sector, 12.22% and 6% in north sudanian, and 55.56% and 25.33% in south sudanian, after the third year of monitoring. In conclusion, in order to restore the shea parks, all seedlings regardless of their origins, will need to be assisted i

    Méthodes de lutte contre les Loranthaceae

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    Les Loranthaceae posent un problème majeur à l’amélioration et à la pérennisation de la production fruitière du karité (Vitellaria paradoxa C. F. Gaertn) en Afrique de l’Ouest. Cet´article présente les resultats des investigations faites en vue d’identifier des méthodes de contrôle des parasites. Deux types d’essais ’’au champ’’ ont été effectués et ont donné des résultats prometteurs: la destruction mécanique et les traitements par herbicides. Additionellement ont été identifiées des variétés résistantes et quelques possibilités de la lutte biologique.The Loranthaceae pose a major problem to the improvement and to the perpetuation of the fruit production of the shea nut (Vitellaria paradoxa C. F. Gaertn) in West Africa. In this article, the results of some investigations made in order to identify methods of control of the parasites are presented. Two methodes were tested in the field and gave promising results: mechanical destruction, and application of herbicides. Additionally we looked for resistent varieties, and for possibilities of biological pest control.Die Loranthaceae stellen ein großes Problem bezüglich der Aufrechterhaltung und Verbesserung der Fruchtproduktion des Schibutterbaunmes (Vitellaria paradoxa C. F. Gaertn) dar. Dieser Arikel präsentiert die Ergebnisse von Untersuchungen zur Bekämpfung dieser Parasiten. Zwei Methoden wurden erfolgversprechend im Feld getestet: mechanische Bekämpfung und Einsatz von Herbiziden. Zusätzlich suchten wir nach resistenten Varietäten und nach Möglichkeiten der biologischen Schädlingsbekämpfung

    Influence of climatic factors and floristic diversity on the foraging activity of Apis mellifera adansonii Latreille in a West African Savannah

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    Abstract The foraging activities of pollinators depend on a variety of factors, such as the availability of pollen and nectar resources or the seasonality. We performed measurements on the activity patterns of Apis mellifera adansonii Latreille by focusing on different factors: (i) we counted the number of bees entering the hives during 10 min per hour starting from 05:00 AM to 06:00 PM, once a month and along the year, (ii) we measured the hive weights at different intervals during the study and (iii) we characterised the diversity of melliferous plants within a 1 km radius around the hives. Our results show that melliferous flora is composed of 83 species. During the dry season, the honey bees foraged on flowering trees and shrubs, whereas in the rainy season herbaceous plants provided forage for honey bees. The results revealed a significant correlation between foraging activity and the mean hive weights ( r  = 0.9) while relative humidity was negatively correlated but not significantly with, respectively, mean hive weights ( r  = −0.5) and foraging activity ( r  = −0.6). Thus, the combination of biotic and abiotic factors resulted in two distinct periods, namely a phase of honey flow followed by a phase of honey scarcity.info:eu-repo/semantics/publishe

    Variability and estimating in fruiting of shea tree (Vitellaria paradoxa C.F. Gaertn) associated to climatic conditions in West Africa: implications for sustainable management and development

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    Shea tree (Vitellaria paradoxa) is one of the main native oil plants with high economic value in Africa. Its fruits are used for food, medicinal, cultural and exportation purposes. However, the lack of efficient tools to assess annual fruit production of the species limits the sustainable management of its resources. Therefore, production statistics are useful to organize the activities of the shea sector. This study aimed to (i) assess the interannual variation in fruit production along a climatic gradient in Burkina Faso, (ii) examine fruit production patterns according to climatic zones and tree size, (iii) assess the contribution of high-yielding trees in the annual potential production and (iv) develop allometric equations for estimating fruit yields of the species. The yield of 212 trees distributed across three climatic zones was monitored over four successive years. Within each climatic zone, fruit production was significantly different among years. Fruit production was positively and significantly correlated with tree size. The interannual variation in fruit production at tree individual level was higher in drier climatic conditions. The mean interindividual synchrony was less than 50% in each zone, suggesting a large range in fruit production patterns of the species. Annually, more than 55% of the total fruit production was supported by high-yielding trees. The best regression models for estimating fruit yields had R2 values of 69–73% with prediction errors ranging from −7% to 4%. Our findings are useful tools for the planning of rational exploitation of shea tree’s resources and its sustainable management
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