Introduction. Shea tree (V.paradoxa C.F. Gaertn.), a species endemic to the Sudaniansavanna woodlands, is dominant in the parklands of West Africa whereit is of great socioeconomic importance. However, shea tree hasbeen reported in recent decades to be threatened by plant parasites,Loranthaceae. Our study aimed to assess possible variation of theimpact of these parasites on shea tree fruit yield in two contrastinghabitats. Materials and methods. We selected 41 weaklyand 41 heavily infected shea tree individuals, of similar size,in a protected area as well as in its adjacent parklands. Shea treetraits such as diameter at breast height, canopy diameter, treeheight, canopy height, number of fruit yielded, number of parasite stumpsper tree and an impact index ratio were assessed on each shea treeindividual. Two-way ANOVA was performed to compare parasite impacton shea tree fruit yield in relation to habitat. Hierarchical cluster, canonicaldiscriminant and one-way ANOVA analyses were used to show quantitativetraits that characterize shea tree groups from habitats. Results.Loranthaceae did not reduce fruit yield significantly either inthe parklands or in the protected area. Quantitative traits tendedto discriminate all pooled shea trees in relation to habitats. Sheatree individuals in parklands were characterized mostly by the highestvalue of number of infected stumps per tree and of the impact index ratio,suggesting that many shea tree individuals in parklands were sensitiveto Loranthaceae impact on their fruit yield. Conclusion.These findings were helpful for implementing some shea tree conservationplans.

In Cameroon, the demand for hive products is growing. Honey and pollen yields are low in the country, partly because of the poor knowledge of the apicultural value of the flora. To determine the apicultural value of Dichrostachys cinerea (L.), Vitellaria paradoxa Gaertn. F., Persea americana Mill. and Securidaca longepedunculata Fres., Apis mellifera adansonii Latreille activity was observed on the flowers of these plants in Ngaoundéré, from December 2001 to May 2002 and from December 2002 to May 2003. The flowers of each plant species were prospected at least 4 days per month, between 0700 and 1800 h, for recording of the nectar and/or pollen foraging behaviour of A. m. adansonii workers. Results show that A. m. adansonii harvest nectar and pollen of V. paradoxa, P. americana and S. longepedunculata. The flowers of D. cinerea were visited for pollen only. The greatest number of workers foraging simultaneously on a plant varied from 34 (D. cinerea) to 1640 (P. americana). A. m. adansonii workers that visited flowers of a given plant species once remained with this nectar source throughout the observation period. Thus V. paradoxa, P. americana and S. longepedunculata could be cultivated and protected to increase honey production, whereas D. cinerea could enable bee-keepers to increase their pollen production as a hive product. During foraging, A. m. adansonii workers increased pollination possibilities of each of the plant species.

Introduction. The widely recognised dietary and socio-economic value of the shea nut and its butter extract seems to have diminished the usefulness attached to the shea fruit pulp, which is also very important. This is evident from the dearth of scientific information on the nutritional content of the pulp. Materials and methods. We determined the nutritional composition of shea fruit pulp of fruits collected in seven locations spread in the southern Guinea savanna, northern Guinea savanna and the Sudan savanna of Nigeria. Results. Analysis of variance revealed a significant effect of agro-ecological zones on carbohydrate, protein, fibre and energy. The southern Guinea savanna zone recorded comparatively more carbohydrate and energy content than the other two zones, while maintaining lower values for protein and fibre. Conversely, all nutritional traits varied significantly across the fruit pulps for fruits collected in the individual locations surveyed in the three zones. Values for carbohydrate, protein and fat ranged from 29.3–45.3%, 2.6–7.0% and 0.7–1.7%, respectively. Correlation analysis established a positive significant relationship between carbohydrate and energy, but its relationship with fibre and protein was negative and significant. Fibre content maintained a negative relationship with energy while being positively correlated with protein. Principal component analysis identified fibre, energy, ash, protein and moisture as nutritional traits that could be used in classifying shea fruit pulp. Discussion. Our study showed that the Nigerian Vitellaria fruit pulp has adequate nutritional content that is comparable with that of other species. The strong statistical linkage between fibre and protein in shea fruits presents an attractive combination, particularly for children of the rural zones with restricted access to the more conventional and expensive food sources.

For recalcitrant seeds, mortality curves of germination versus water content typically imply a wide range of desiccation sensitivities within a seed population. However, seed to seed differences in water content, during desiccation, may confound our interpretation of these mortality plots. Here, we illustrate this problem for two batches of Vitellaria paradoxa (Sapotaceae) seeds collected in 1996 and 2002. Whole seeds were desiccated to various target water contents (TWCs) using silica gel. During desiccation, smaller seeds in the population dried most rapidly. Consequently, there was a significant linear relationship between whole-seed water content and seed mass during the drying process. In addition, following desiccation to low TWCs, only the largest seeds in the population retained viability. Taken together, this suggests that the larger seeds survived, not as a consequence of great relative desiccation tolerance, but as a result of taking longer to desiccate. Subsequently, the critical water content (CWC) for viability loss was calculated, based on the assumptions that in the seed population whole-seed water content during desiccation was normally distributed and the smallest, and hence driest, seeds were killed first. Using this approach, the driest seeds in the population that were killed, at each TWC, were always below a single CWC (c. 20% and 26% in 1996 and 2002, respectively). In subsequent experiments the effect of seed size variation on the response to desiccation was confirmed by conducting desiccation screens on seeds sorted into two discrete size classes, i.e. the seed-lot heterogeneity in mass was reduced. Using this approach, the mortality curves had a steeper slope. Furthermore, data for 24 tropical tree species from the Database of Tropical Tree Seed Research (DABATTS) revealed that seed lots with less variability in mass had steeper mortality curves. Thus, taken together, the data suggest that, at least for whole seeds, the wide range of desiccation sensitivities typically inferred is an artefact of seed to seed variation in mass, and hence water contents, during drying.

Introduction. Le karité a une fructification aléatoire. L’objectif de notre étude a été de tester la technique d’incision annulaire comme outil de contrôle de cette fructification irrégulière. Matériel et méthodes. En août 2003, une incision annulaire portant sur les trois quarts du pourtour d’une branche a été effectuée, jusqu’à l’aubier, sur 29 karités du terroir de Bondoukuy (Burkina Faso) ; une branche de chacun de ces mêmes arbres a servi de témoin. En 2004, un essai factoriel d’incision a été entrepris ; il a porté sur deux sites de ce même terroir, deux périodes de traitement (fin août et fin novembre), trois ampleurs d’incisions (50 %, 75 % et 100 %) et cinq karités utilisés par traitement. Ce sont donc 60 karités multicaules qui ont été étudiés, un des troncs de chacun d’eux servant de témoin. La proportion de rameaux florifères (%rFl) et le nombre de fleurs (nFl) et de fruits (nFr) formés par rameaux traités et témoins ont été comptabilisés puis analysés. Résultats. Par rapport aux branches témoins, l’incision annulaire a accru de 17 % le (%rFl), 54 % le (nFl) et 100 % le (nFr) par rameau. Les périodes et ampleurs d’incision testées n’ont pas montré de différences entre elles, mais elles ont permis aux branches traitées d’obtenir un (%rFl) supérieur à celle des branches témoins. Quelle que soit la variable considérée, il est apparu une différence de performances de reproduction entre les karités des sites testés ; l’efficacité de l’incision annulaire serait donc liée aux conditions édaphiques de développement de l’arbre. Discussion et conclusion. La technique d’’incision annulaire peut donc être utilisée pour contrôler l’irrégularité de la fructification du karité. Néanmoins, des études complémentaires se révèlent indispensables pour déterminer l’effet de la période de l’incision sur le grossissement et la composition chimique des fruits.

Introduction. Notre étude a eu pour objectif de comparer la production fruitière des karités de parcs agroforestiers à celle d’arbres présents dans les formations naturelles. Matériel et méthodes. La production fruitière de karités a été évaluée à l’aide d’un inventaire systématique effectué en 2002 sur trois transects établis à cheval sur deux types de peuplements : un parc agroforestier et une formation naturelle. Cet inventaire a permis de prélever dix fruits par arbre, qui ont été mesurés et pesés. Le rendement en amandes sèches a été évalué sur la production de deux lots de 25 arbres localisés l’un dans un parc agroforestier et l’autre dans une formation naturelle. Résultats. Nos résultats ont montré que 94 % des arbres des parcs agroforestiers avaient fructifié pendant la période d’étude contre 56 % des arbres présents dans les formations naturelles. Le rendement moyen en amandes des arbres des parcs, d’environ 4 kg·arbre–1, a été statistiquement supérieur à celui des arbres des formations naturelles (1,5 kg·arbre–1 environ). Il en a été de même pour les longueurs moyennes (3,7 cm contre 2,9 cm) et les largeurs moyennes (3,0 cm contre 2,3 cm) des fruits des arbres analysés dans l’un et l’autre des deux types de peuplements échantillonnés. Le poids moyen d’une amande sèche des arbres des parcs agroforestiers, de 4,5 g environ, a différé significativement de celui des arbres des formations naturelles (2,6 g). Discussion et conclusion. Les karités des parcs agroforestiers peuvent donc être considérés comme des « arbres-plus » par rapport à ceux des formations naturelles.