Economically efficient and environmentally friendly technology is essential for sustainable agricultural production. To optimize cowpea production through an economically profitable and environmentally friendly phytosanitary treatment technology, trials were conducted in a station based on Acarius 18 EC at a rate of 1 liter/ha against the main cowpea insect pests. A complete randomized block device with three replications of four objects each with two sub-trials: an early competition (EC) sub-trial and a late competition (LC) sub-trial were adopted. Seed yield and the critical period for phytosanitary treatment have been determined. The best yields were obtained on objects that received the first treatment 28 days after sowing (DAS) (2.13 t/ha on average) for EC and on objects that received the last treatment 42 DAS (2.23 t/ha on average) for LC. Under the conditions of our study, the critical period of phytosanitary treatment against cowpea pests (VITOCO) for optimum yield is then between 28 and 42 DAS.

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Objectif : La présente étude vise à évaluer et à prioriser le niveau de satisfaction des utilités attendues des cultivars d’igname auprès 1032 acteurs locaux de la filière igname au Sud-ouest des Savanes Sèches au Togo. Méthodologie et résultats: Le brainstorming, le scoring et les avis d’experts, ont permis la définition de quinze descripteurs d’utilités des cultivars, dont les notes d’appréciation ont révélé une corrélation positive significative entre attributs. L’ensemble des attributs a été priorisé en trois classes selon la loi 80/20 (la loi de Pareto). Valeur marchande, nom de cultivar à connotation d’image et gros et longs tubercules ont constitué la principale classe d’attributs avec des notes moyennes d’utilités significatives et respectivement de 9,52 ; 7,28 et 2,28. Ils ont satisfait à 63,91% des utilités cumulées attendues des attributs de tous les cultivars. De tous, le lieu de production à image de qualité (0,80) et la résilience aux divers stresseurs, (0,34) ont été faiblement apprécié. Les effets de l’âge et du sexe des participants sur les notes d’appréciation de l’utilité n‘ont pas été perçus. Conclusion et application des résultats: Les utilités cumulées attendues ont été satisfaites à 63,91% par 20% des attributs en culture d’igname et une faible atteinte d’utilité cumulée de 36,07% par 80% du reste des attributs. De futurs programmes d’amélioration variétale pourront prendre en compte la satisfaction des utilités attendues des ignames. Une piste de production labélisée des tubercules et de leurs transformations élargies aux potentialités de tous les cultivars peuvent constituer une application à envisager sur la base des présents résultats et limiter ainsi l’érosion génétique de la culture d’igname. Mots clés : ignames, attributs, priorisation, utilités attendues, Savanes Sèches, Togo. Gnon et al., J. Appl. Biosci. 2020 Evaluation d’utilités attendues des attributs de cultivars de l’igname : base d’une gestion locale de l’agrobiodiversité de Dioscorea spp au Sud-ouest des Savanes Sèches au Togo (Afrique de l’Ouest) 15765 Evaluation of expected utilities of yam cultivar attributes : a local base for agrobiodiversty management of Dioscorea spp in Southwest Dry Savannahs in Togo (West Africa) ABSTRACT Objectives: The present study aims to evaluate and prioritize the level of satisfaction of the expected utilities of yam cultivars by local actors of the yam sector in the South-West of Dry Savannah in Togo. Methodology and results: The scoring and the expert opinions, allowed the definition of fifteen cultivar attribute descriptors by 1032 actors of the yam sector followed by their prioritization in three distinct classes by the law 80/20. The average utilities of the main attributes: market value, cultivar name with image connotation and large and long tubers were respectively 9.52; 7.28 and 2.28. They represented 63.91% of the expected cumulative utilities of all attributes. The effects of age and sex on expected utility ratings were not seen in this study. Conclusion and application of the findings: 20% of the attributes fulfilled 63.91% of cumulative utilities expected in yam culture and posing the problem of the low cumulative utility of 36.07% by 80% of the attributes. Thus, future research to improve a satisfaction of utilities of the 80% of attributes is necessary. Future varietal improvement programs, may take into account the satisfaction of the expected utilities of yams. A path of labeled production of tubers and their transformations extended to the potential of all cultivars may constitute an application to be considered on the basis of the present results and thus limit the genetic erosion of the yam crop. Keywords: yams, attributes, prioritization, expected utilities, Dry Savannahs, Togo.

Extensive yam production by means of slash-and-burn cultivation practice holds a prominent place in the southwest of the dry savannahs of Togo cultivation systems. Like in West Africa, yam cultivation in Togo is subject to many constraints that have remained insufficiently known. These constraints lead to lower yields, and volumes of tubers in the field at postharvest, and affect the productivity of this sector. Seeking to identify the main causes of the decline in yam production or productivity in Togo, the present study has carried out a participatory diagnosis with producers and stakeholders in the yam sector in 27 villages in the dry savannah zone of Togo and has identified 15 main factors with severity levels between 0.03 and 3.32. Average losses of yam tubers, seed yield and market value in one cropping season represent 20.62 ± 1.86, 15.72 ± 3.13% and 45.42 ± 5.63% per hectare of 4000 mounds, respectively. The 80/20 law and the ABC analysis have revealed that the variability and instability of rainfall, the continuous decline of soil fertility and the insufficiency of seed are perceived by farmers as constraints to yam production. The study, therefore, indicates that mitigation of these major factors, which account for about 20% of causal factors affecting yam productivity, can improve yam tubers production. However, the high severity of rainfall anomalies mandates future work on local perceptions of the manifestations of climatic variability and the evaluation of local practices for improving the resilience of yam cultivation in the face of climate impacts in Togo.

Prévalence et diversité des spores des champignons mycorhiziens arbusculaires en culture de riz sous les différents systèmes de culture de riz au Togo.