Combretum nigricans is a species of high socio-economic importance in West Africa and particularly in Burkina Faso. However, the strong anthropic pressure and the lack of knowledge on the different modes of regeneration constitute the main factors which hinder the stability of the stands of the species. The objective of this study was to evaluate the ability of C. nigricans for vegetative propagation. To do this, two modes of vegetative regeneration were tested, namely root and stem cuttings and air layering. The results show that C. nigricans does not respond to vegetative propagation by root cuttings. However, tests on aerial fragment cuttings show that time period has a highly significant effect (p< 0.001) on the ability of the cuttings to vegetatively recover. The survival of the cuttings is strongly influenced by the diameter of the fragments (p< 0.001) and also varies from one period to another. Air layering carried out in March (during vegetative rest) gave after 06 months of follow-up a success rate of 45% with a high success rate for branches 16 to 18 mm in diameter. These preliminary results show that it is possible to reproduce C. nigricans by stem cuttings and air layering. These results are promising and open interesting perspectives for the improvement of gum production in Burkina Faso.

This study was carried out to assess the seed-borne fungi of onion in Burkina Faso. Eighteen onion seed samples were collected from local farmers and wholesalers of vegetable seeds in the country and were investigated for fungi. The investigation was done using the “blotter method” on dry seeds and on seedlings. Fungal contamination was detected in all 18 tested samples. Seventeen fungal species belonging to 11 fungal genera were identified in the seed samples: Aspergillus was detected in 17 samples, Fusarium and Rhizopus in 15 samples, Cladosporium in 14 samples and Penicillium in 13 samples. Aspergillus niger and Fusarium oxysporum, known to be the causal agents of black mould and basal rot diseases, were detected in 17 and 11 samples, respectively, by seed analysis and in 10 and 9 samples, respectively, by seedling analysis. The infection rates by the fungal species varied from 0 to 90.3% for A. niger and from 0 to 13.5% for F. oxysporum. Alternaria porri, the causal agent of purple blotch disease was recorded lowly on two seed samples at infection rates of 0,5 and 1%. Exotic seed samples showed better health quality compared to local seed samples. These results indicated that the seeds locally produced by farmers in Burkina Faso are for low health quality and needs strong treatments before use to avoid diseases appearance in fields.