Post-Harvest Fungi Associated with Cowpea (Vigna unguiculata L. Walp.) Seeds Produced in Burkina Faso

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Résumé

Cowpea is a very popular foodstuff among people in sub-Saharan Africa. In Burkina Faso, it is the main food legume, especially in rural areas. Its pro- duction is facing difficulties including post-harvest losses caused by fungi. Therefore, the objective of this study was to isolate and identify fungal strains associated with cowpea seeds produced in Burkina Faso. Thus, a total of 108 seed samples were collected in the three agro-ecological zones of Burkina Fa- so. The sanitary analysis of the seeds was carried out using the direct contact method. The isolation and purification of the isolates were performed on Po- tato Dextrose Agar medium while their identification was done through macroscopic and microscopic phenotypical characterization using different cul- ture media (Potato Dextrose Agar (PDA), Malt Extract Agar (MEA) and Cza- peck Dox Agar (CZA)) and different identification keys. A total of 10 fungal species were isolated, with predominance of Aspergillus flavus,Aspegillus niger, Macrophomina phaseolina,Fusarium oxysporium and Rhizopus sp. whose infection rates were 70.8% to 100% of seed samples. In addition to being present in all three zones, the infection rates ofAspergillus flavus (56.55%),
Aspergillus niger (20.35%) and Rhizopus (32.80%) were higher in the Sahelian zone. In the Sudano-Sahelian zone, Macrophomina (50.66%) and Fusarium (18.88%) presented the highest infection rates, while Penicillium sp. showed the highest infection rate (2.84%) in the Sudanian zone. This finding demonstrated the necessity to improve post-harvest and conservation tech-niques of cowpea to limit crop losses and preserve the sanitary quality of this important foodstuff.

Mots-clés

Cowpea, Seed-Borne Fungi, Agro-Ecological Zones, Burkina Faso