Performance of Varieties of Gboma ( Solanum Macrocarpon ) under Disease Pressure with Organic Amendment in Southern Benin

‘Gboma’, the African eggplant, is one of the traditional vegetables in Benin that has not been studied in terms of varietal differences and reaction to diseases. Colletotrichum stem rot of Solanum macrocarpon ‘Gboma’ is a  widespread disease in S. macrocarpon cultivated areas of South Benin. This study is focused on the disease diversity on S. macrocarpon and determines the behaviour of the varieties of S. macrocarpon to diseases using different doses of organic fertiliser. The appearance of disease symptoms was investigated in two locations (Cotonou and Seme) on six S. macrocarpon varieties fertilised with 20 t ha -1 and 40 t ha -1 of chicken manure in a completely randomised block design with 4 replications. The stem rot of S. macrocarpon caused by the fungus Colletotrichum capsici was the only recorded disease. The incidence of the disease was measured as area under the incidence progress curve. The disease incidence was significantly higher in Somalie Gboma variety and significantly lower in the Abidjan Gboma variety at both locations. Regarding the effect of amended manure, the disease incidence was low in plots amended with 40 t ha -1 and high in those amended with 20 t ha -1 , with significant differences (p = 0.0237) obtained in the Cotonou location. This is in Benin the first record of C. capsici as pathogen of S. macrocarpon with positive Koch postulate reaction and of the Abidjan Gboma as resistant variety of S. macrocarpon to C. capsici . For this disease reduction and yield increase, organic amendment of 40 t ha -1 chicken manure is recommended. Keywords : Traditional vegetable, Disease diversity, African eggplant, Solanum macrocarpon , Indigenous vegetable, Benin. ‘Gboman’, la grande morelle ( Solanum macrocarpon ), est l’un des legumes feuilles traditionnels du Benin qui n’ont pas fait l’objet d’une etude de comportement varietale aux maladies. La pourriture de tige de S. macrocarpon provoquee par Colletotrichum est repandue dans les zones de culture au sud du Benin. Cet article met en exergue la diversite des maladies infeodees a S. macrocarpon et etudie le comportement varietal de ce legume face aux maladies avec l’utilisation de doses variables de fertilisant organique. Les symptomes des maladies ont ete evalues dans deux localites (Cotonou et Seme) sur six varietes de S. macrocarpon fertilisees avec 20 t ha -1 et 40 t ha -1 dans un dispositif de bloc aleatoire complet a quatre repetitions. La pourriture de tige de S. macrocarpon causee par le champignon Colletotrichum capsici a ete la seule maladie observee. L’incidence de la maladie a ete mesuree comme l’aire sous la courbe de progression de l’incidence de la maladie. Elle a ete significativement elevee chez la variete Somalie Gboma et significativement faible chez la variete Abidjan Gboma dans les deux localites. En ce qui concerne l’effet de la matiere organique apportee aux plants de S. macrocarpon , l’incidence de la maladie a ete faible sur les parcelles amendees avec 40 t de fiente a l’hectare et elevee sur les parcelles amendees avec 20 t de fiente a l’hectare avec une difference significative dans la localite de Cotonou (p = 0,0237). Ce travail rapporte pour la premiere fois, l’infestation de S. macrocarpon par C. capsici et la variete Abidjan Gboma comme resistante a C. capsici . Pour reduire cette maladie et augmenter le rendement, un amendement organique de 40 t ha -1 de fiente de volaille est recommande. Mots cles : Legumes traditionnels, Solanum macrocarpon , diversite de maladies, Colletotrichum capsici , Benin