Variability of some biochemical traits of Sclerocarya birrea (A. Rich.) Hochst. fruits in Burkina Faso. Abstract-Introduction. Sclerocarya birrea (A. Rich.) Hochst. subsp. birrea is an indigenous fruit tree very widespread in Burkina Faso. Although very appreciated by the rural populations for its fruit, it remains not domesticated and underutilized. Until now, studies regarding fruit variation and quality have been focused on S. birrea subsp. caffra originating in Southern Africa. Materials and methods. Fruit biochemical composition of 106 Sclerocarya birrea trees was studied in Burkina Faso along a North-South transect (climatic gradient) starting from five quantitative characters of the fruit and seed. The reducing sugar and total sugar rate, the total free acidity content and the [total free acidity / total soluble sugars] ratio were defined for the pulp. The lipid content of seeds was measured. Results and discussion. For the studied characters, the analysis of the results highlighted a great inter-and intra-population variability. The inter-population variability is explained by the climatic gradient which characterizes the sampling zone. Conclusion. The highlighted variability of the S. birrea subsp. birrea fruit composition could be used as a basis for a breeding program. Burkina Faso / Sclerocarya birrea / fruits / proximate composition / chemical composition / site factors / agroclimatic zones Variabilité de quelques caractères biochimiques des fruits de Sclerocarya birrea (A. Rich.) Hochst. au Burkina Faso. Résumé-Introduction. Sclerocarya birrea (A. Rich.) Hochst. subsp. birrea est un fruitier sauvage très répandu au Burkina Faso. Bien que très apprécié par les populations rurales, il demeure non domestiqué et sous utilisé. Jusqu'à présent, les études sur la variation et la qualité des fruits se sont concentrées sur la sous espèce caffra, originaire de l'Afrique australe. Matériel et méthodes. La composition biochimique des fruits de 106 arbres de Sclerocarya birrea au Burkina Faso a été étudiée le long d'un transect Nord-Sud (gradient climatique) traversant le Burkina Faso à partir de cinq caractères quantitatifs du fruit et de la graine. Le taux en sucres totaux et en sucres réducteurs, la teneur en acidité libre totale et le rapport [acidité libre totale / sucres solubles totaux] ont été définis dans la pulpe. La teneur en lipides des graines a été déterminée. Résultats et discussion. Pour les caractères étudiés, l'analyse des résultats a mis en évidence une grande variabilité inter-et intra-population. La variabilité inter-population s'explique par le gradient climatique qui caractérise la zone d'échantillonnage. Conclusion. La variabilité de la composition des fruits de Sclerocarya birrea subsp. birrea mise en évidence pourra servir de base pour un programme d'amélioration. Burkina Faso / Sclerocarya birrea / fruits / composition globale / composition chimique / facteur lié au site/ zone agroclimatique 1 Lab. Génét. Biotechnol. Vég.

Evaluation of intra specific variability is a key step toward conservation and sustainable use of species.This study was carried out to describe the morphotypes of Solenostemon rotundifolius (Lamiaceae) based on quantitative traits. Three accessions (E02, E35 and E20), representing the morphotypes "A", "B" and "C" were characterised in Randomised Complete Block Design with three replications. Twentyfour (24) traits related to the cycle, the canopy size, the production and the tuber size were measured. Analysis of variance (ANOVA) revealed significant difference of the morphotypes (at level P = 0.05 or 0.01) in the traits related to the canopy and leaf size, the crop cycle, the production and the tuber size. The morphotype "A" was identified to be the most promising one. It was early maturing (107 to 113 days) and the most productive (134.98 g per plant). The cycle of the morphotypes "B" and "C" varied from 154 to 164 days and 118 to 149 days and tuber weight per plant was 46.03 and 45.17 g, respectively. This work is a step toward a full description of the morphotypes of S. rotundifolius. It provided a useful list of quantitative traits that can be used as descriptors for future description of genetic resources of S. rotundifolius and for breeding purposes.

Hibiscus cannabinus is a traditional leafy-vegetable consumed more and more in Burkina Faso. Its leaves and fruits are some good food supplement against nutritional deficiencies. Its fibers are also a source of income for households. Despite of its nutritional an economic potential, this species is underdeveloped in Burkina Faso. The study aims to determine genetic variability and level of heritability among agronomic interest traits of H. cannabinus using agro-morphological descriptors. This enable to identify outstanding accessions which could be involved in further breeding programs. A total of 70 accessions of H. cannabinus were characterized according randomized incomplete block, using 5 qualitative characters and 15 quantitative characters. The study showed great variability for most of the qualitative and quantitative characteristics studied. Several correlations were observed between characters related to the biomass, the fruits and the fibers production. These correlations are particularly interesting because the improvement of only one character induces improvement of the others. The study, moreover, shows high broad sense heritability (H 2) and weak differences between the phenotypic (PCV) and genotypic (GCV) coefficients of variation. These results indicate that the characters expression is under genetic control. So a direct selection method of H. cannabinus improvement is possible for these characters.

Rice is the basic cereal of the populations of the areas of Tandjilé and Western Mayo Kebbi, in the south of Chad. The rice productivity is, however, low: less than 1 t/ha. This is related to several factors, of which the strong infestation of rice plantation into adventitious and lack of improved varieties with high productivity. Among the bad frequent grasses, harmful for cultivated rice, the species like Oryza sativa, Oryza barthii and Oryza longistaminata show the strong dynamic ones of infestation in the rice plantations of flooded plains of the areas of Tandjilé and Western Mayo Kebbi. The agromorphological characterization of the samples of the prospection-collection from October 2005 to Mars 2006 revealed the existence of three types of rice in the zone: wild rice, adventitious rice and cultivated rice. The group of cultivated rice breaks up into three pennies groups on the basis of duration of sowing-heading cycle. The objective of this study was to characterize the agromorphological features of these groups.

Solenostemon rotundifolius or country potato is a tropical multipurpose tuber crop species. It has been one of the staple crops in West Africa but currently, its genetic resources are in a process of disappearing. Characterization of S. rotundifolius genetic variability is recognized as a prior intervention to support a sustainable conservation and use of its genetic resources. For identifying suitable descriptors for S. rotundifolius, a morphoagronomical characterization was carried out on 155 cultivars from Burkina Faso. A total of 50 morphological traits (16 qualitative and 34 quantitative) related to the foliage, the cycle and the tubers were scored. The results showed variability within cultivars for the foliage, the cycle and the potential yield (number and weight of tubers). However, no significant variability was found for tubers size. Cultivars from different geographical origin discriminated for the cycle and the potential yield. Significant correlations were found between the cycle, the foliage and the potential yield. Most of the qualitative morphological traits were shown to be varietal criteria. The studied morphological traits could be used as descriptors for S. rotundifolius germplasm characterization and for breeding purpose.