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Water deficit in tropical countries is the main factor limiting agricultural production. This study aimed at evaluating the level of resistance to water deficiency of three local maize cultivars in Benin. The effects of water stress induced supply of 100 (control), 50 and 25 % of the Readily Usable Reserve (RUR) from the 40th day after sowing to the end of the production cycle were studied. The experimental design used was a split plot with 4 replicates. Phenological, agro-morphological and agro-physiological parameters of plants were evaluated. Water deficit reduced plants height, root volume, root dry matter and total leaf area during the flowering stage. The date of female inflorescence setting was extended by water deficiency. Water deficiency also reduced the mean number of cobs per plant from 0.855 ± 0.38 (100% RUR) to 0.64 ± 0.019 (50% RUR) and 0.58 ± 0.17 (25% RUR). Furthermore, 1000 grains weight dropped from 264.63 ± 53.58 g (100 % RUR) to 223.88 ± 37.9 g (50 % RUR) and 217.63 ± 42.66 g (25% RUR). The cultivar Bafogbali was the most resistant to water stress. The variety EV DT 97 and the cultivar Souantokoui were the most affected by the water deficiency.Keywords: Water pattern, drought, easily usable reserves, Zea mays, Benin.

Selection of Soybean Varieties for Resistance to Bacterial Pustule in Benin. Bacterial pustule caused by Xanthomonas axonopodis pv. glycines is a dreaded disease on soybeans inducing considerable yield losses worldwide. The aim of this study is to test 16 soybean varieties for resistance to bacterial pustule under natural infection and artificial inoculation. The study was conducted under greenhouse and field conditions at the experimental farm of the University of Parakou from July to October in 2013 and in 2014. The results show that the varieties JUPITER, ISRA25/72, TGX1985-77F, TGX1910-2F and TGX1985-11F are sensitive to moderately sensitive. The varieties TGX1448-2E, TGX1987-62F, TGX1990-15F, TGX1987-10F, TGX1835-10F, TGX1740-2F and TGX1440-1E are moderately resistant to resistant. The varieties TGX1988-5F, TGX1910-14F, TGX1989-21F and TGX1989-19F revealed moderately resistant in the greenhouse, but sensitive to moderately sensitive in the field. In 2013, yield losses from 2.7 to 28.1% were recorded with the varieties TGX1910-2F, ISRA25/72, JUPITER, TGX1910-2F, TGX1987-10F, TGX1835-10F and TGX1740-2F. Yield losses were calculated for each variety considering the yield difference between the natural infection and the artificial inoculation. The difference was than divided by the yield obtained in the natural infection. In 2014, varieties TGX1985-77F, TGX1740-2F, ISRA25/72, TGX1987-62F and TGX1910-14F showed losses ranging from 4.7 to 21.4%. The other varieties showed yield increases from 2.7 to 26% in 2013 and from 2.2 to 36.6% in 2014. With variety TGX1985-11F neither yield loss nor gain were observed over the two years. T For the 16 tested varieties, TGX1987-62F and TGX1990-15F are the most resistant; while TGX1989-19F, TGX1985-11F, TGX1440-1E, TGX1985-77F and TGX1910-14F are partial resistant. Those varieties have a high yield and could be recommended to the farmers. The two most resistant varieties could be integrated in a plant breeding program.

To improve soybean (Glycine max L.) production in Benin, knowledge of bacterial diseases is needed. The objective of this study was to establish the disease occurrence and to identify Xanthomonas axonopodis pv. glycines, the causal agent of soybean bacterial pustule. Soybean bacterial pustule disease was studied during the flowering and at pod maturation, in thirty four sites of the main soybean cultivation areas in eight districts of the Guinea Savanna in Benin. Twenty and 10 soybean plants were randomly inspected for incidence and severity, respectively, on two diagonals through the field. Seven isolates from 6 different locations with highest severity, were submitted for virulence tests. The most virulent was characterised by Polymerase Chain Reaction. Bacterial pustules were present in 33 of 34 sites. Incidence and severity per district ranged from 15.8 to 70%, and 6.0 to 26.14%, respectively. Severity was highest at Binassi (34.33%) in Perere and Baka (33.2%) in Parakou. Among the seven strains isolated, UP-PK-S3 from Baka (Parakou) was the most virulent, and was characterised as Xanthomonas axonopodis pv. glycines.Keywords: Glycine max, incidence, Xanthomonas axonopodis

Du fait de ses multiples problèmes, la culture du coton au Bénin est aujourd’hui de plus en plus négligée, bien qu’ayant contribué pendant plusieurs années à la croissance économique du pays. De nombreux paysans abandonnent la production au détriment des cultures céréalières. Le présent travail vise à analyser la rentabilité de la production du coton dans cette zone dans le cadre d‘une meilleure connaissance de la filière. A cet effet, une enquête à été conduite auprès de trente et un producteurs de coton de la Commune de Ouaké. Ceuxci ont été choisis de manière participative avec les agents du Centre Communal pour la Production Agricole (CeCPA) Ouaké. Les données sur les caractéristiques sociodémographiques, les prix et quantités des inputs et outputs utilisés dans la production du coton ont été collectées auprès des producteurs échantillonnés. L’analyse de la productivité moyenne du travail et du ratio bénéfice coûts, avec une superficie moyenne de 1,04 ha et une productivité moyenne de 1085,29 kg, montre que la production cotonnière n’est pas économiquement rentable pour 93,5 % des producteurs. Ces résultats indiquent la nécessité de la mise en oeuvre d’actions devant concourir à la relance de la production, par de meilleures stratégies dans le cadre d’une agriculture durable dans la zone d’étude et au Bénin.Mots clé : Culture d’exportation, indicateurs de rentabilité, Ouaké, Nord-ouest Bénin, Afrique de l’Ouest.Because of its multiple problems, the culture of cotton in Republic of Benin nowadays is more and more neglected, although having contributed during several years to the economic growth of the country. Many peasants are giving up the production for the cereal cultures. This work aims at analyzing the profitability of the production of cotton in this zone withinthe framework of the promotion of the culture. To this end, an investigation was undertaken with thirty one cotton producers, in the Commune of Ouaké. Those were selected in a participative way with the agents of Centre Communal pour la Production Agricole (CeCPA) of the study aera : Ouaké. Data concerning the sociodemographic characteristics, the prices and quantities of the inputs and outputs used in the production of cotton were collected from the sampled producers. The analysis of the average productivity of work and the ratio benefit costs, with an average surface of 1.04 ha and an average productivity of 1085.29 kg for the study site, showed that the cotton production is not economically profitable for 93.5 % of the producers. These results indicated the need for urgent actions implementation to contribute to the promotion of the production, throughout better strategies and for a sustainable agriculture in the study site.Keywords : Export cultures, indicators of profitability, Ouaké, North-west Benin, West Africa.

La typologie et la structure des parcs agroforestiers des communes Gogounou et de Ouaké dans la région soudanienne du Nord Bénin ont été investiguées. A partir de 180 relevés, divers paramètres floristiques et dendrométriques des ligneux ont été calculés. La typologie des parcs a été réalisée à travers l’analyse hiérarchique en considérant les paramètres tels que la richesse spécifique, la surface terrière et la densité des arbres. La structure en diamètre des ligneux a été ajustée à la distribution de Weibull à trois paramètres. Bien que les deux espèces caractéristiques (néré et karité) représentent 71 à 76 % de l’effectif total des ligneux épargnés dans les champs et jachères, les parcs agroforestiers du milieu d’étude ne sont pas uniformes. Quatre types de parcs agroforestiers, qui s’ordonnent suivant la maturité et les modes de gestion, ont été discriminés : à Gogounou, le parc à Vitellaria paradoxa, Parkia biglobosa et des ligneux fourragers dans les arrondissements de Gounarou et de Zougou ; le parc à Vitellaria paradoxa, Parkia biglobosa et Adansonia digitata dans l’arrondissement de Bagou ; à Ouaké, le parc à Parkia biglobosa et des essences exotiques dans les arrondissements de Badjoudè et Sèmèrè ; le parc constitué presque exclusivement de Parkia biglobosa dans l’arrondissement de Tchalinga. On note une différence hautement significative pour la plupart des variables floristiques et dendrométriques (richesse spécifique, diversité spécifique, Equitabilité de Pielou et surface terrière). La structure en diamètre des parcs agroforestiers est normale dans les deux parcs à karité et néré de Gogounou et dissymétrique gauche pour les deux parcs à dominance néré de Ouaké. Il est préconisé la promotion de la régénération naturelle assistée pour améliorer les taux de survie des jeunes plants des ligneux protégés ; et une meilleure gestion des parcs agroforestiers qui garantirait la multifonctionnalité des ligneux épargnés.Mots clés : Parc agroforestier, savanes, Nord Bénin.The typology and structural characteristics of agroforestry parklands from Gogounou and Ouaké districts in the soudanian zone of north Benin were studied through linear transects and dendrometric relevés. The typology was derived from hierarchical classification, basedon species richness, basal area and stem density. The diameter structure was adjusted to Weibull distribution with 3 parameters. The two characteristics species (i.e. Parkia biglobosa and Vitellaria paradoxa) represented 71 to 76% of the abundance of protected stems in these parklands. Four parklands types were discriminated, according to maturity and managements methods : - in Gogounou district, they were Parkia biglobosa and Vitellaria paradoxa parkland with fodder tree species at Gounarou and Zougou; Parkia biglobosa, Vitellaria paradoxa and Adansonia digitata parkland at Bagou ; - in Ouaké district, they were Parkia biglobosa parkland with exotic trees at Badjoudè and Sèmèrè; Parkia biglobosa dominated parkland at Tchalinga. Values of the floristic, dendrometric and structural parameters varied from one park to another; and the four parks were statistically different regarding species richness, Shannon diversity index, Pielou evenness index and basal area. The stem diameter structure showed a bell shape type for the two parks from Gogounou; and a left-dissymmetry type for those from Ouaké. To improve these parklands, we suggested assisted regeneration and a better management of Parkia biglobosa and Vitellaria paradoxa trees.Keywords : Agroforestry parkland, savannah, North Benin.

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