Caracterisation des performances de croissance et de resistances aux maladies et aux ravageurs de sept (7) varietes de patate douce (Ipomoea Batatas (l), Lam., 1793) dans la region de bouake, Cote d’Ivoire

La production de la patate douce, Ipomoea batatas (L.) Lam., reste confrontée à de nombreuses contraintes agronomiques. Pour mieux faire face à ces contraintes, une étude a été réalisée dans le but de déterminer les caractères agronomiques de sept (7) variétés de patate douce cultivée au centre de la Côte d’Ivoire (Bouaké) afin de sélectionner les variétés les plus adaptées.  Dans cette étude, le taux de survie, la biomasse aérienne, la résistance aux insectes et ravageurs ont été évalués. Les résultats obtenus ont montré que les variétés Covington, CIP et Irène ont enregistré les meilleurs taux de survie. Au niveau de la biomasse aérienne la variété Irène s’est distinguée des autres variétés. La variété Fadanga a été moins sensibles pour l’ensemble des nuisibles influençant la patate douce.   The production of the sweet potato, Ipomoea batatas (L.) Lam., still faces many agronomic constraints. To better face these constraints, a study was carried out in order to determine the agronomic characteristics of seven (7) varieties of sweet potato cultivated in the center of Côte d'Ivoire (Bouaké) in order to select the most suitable varieties. In this study, survival rate, aboveground biomass, resistance to insects and pests were assessed. The results obtained show that the Covington, CIP, and Irene varieties recorded the best survival rates. In terms of aerial biomass, the Irene variety stood out from other varieties. The Fadanga variety was less susceptible to all the pests influencing the sweet potato

Etat Phytosanitaire Dans Les Plantations Industrielles De Bananiers Dans La Lutte Contre La Cercosporiose Noire En Côte d’Ivoire

La cercosporiose noire causée par le champignon Mycosphaerella fijiensis détruit le feuillage du bananier. Cette maladie apparaît sous forme de petits tirets noirs allongés sur les feuilles qui évoluent très rapidement en nécroses généralisées qui peuvent aboutir à la destruction totale des feuilles du bananier avant la récolte du régime. Elle entraîne ainsi une diminution des rendements et une maturation précoce des fruits. Les stratégies de lutte raisonnée pour le contrôle de la maladie qui s’appuient sur les méthodes d’avertissement, reposent sur le suivi de la maladie en bananeraie et sur l’observation de descripteurs climatiques (pluies, humidité, etc.). Cette étude portant sur l’environnement de production et sur l’organisation des équipes phytosanitaires, a été menée de 2008 à 2012 dans douze plantations industrielles de bananiers de Côte d’Ivoire. L’évaluation de l’état phytosanitaire a porté sur les caractéristiques environnementales (contrôle de l’enherbement, gestion de l’humidité et bordures des parcelles) et sur l’organisation des équipes phytosanitaires. Les résultats ont montré que les plantations Eglin à Agboville, à Azaguié et à Motobé ; WANITA Dabou ont présenté un état sanitaire acceptable, avec une nette progression des paramètres environnementaux observés. Quant aux plantations TIABAM, Rouchard Tagbadié, CDBCI Azaguié et SAKJ Aboisso, elles présentent des inquiétudes dans le redressement de l’état sanitaire de leurs parcelles. Dès 2010, toutesles plantations avaient la présence des équipes phytosanitaires qui numérisaient les observations de la maladie et faisaient le suivi régulier de l’évolution de la maladie. L’ensemble des plantations a montré une évolution positive dans la prise en compte des paramètres essentiels pour une gestion efficiente de la cercosporiose noire. Black Sigatoka caused by the fungus Mycosphaerella fijiensis, destroys the foliage of banana. This disease appears as small elongated black dashes on the leaves which develop very rapidly into widespread necrosis which can lead to total destruction of banana leaves before the harvest of the bunch. It thus leads to reduced yields and early fruit ripening. Rational disease control strategies based on warning methods are based on monitoring the disease in banana plantations and on the observation of climatic descriptors (rainfall, humidity, etc.). This study on the production environment and the organization of phytosanitary teams was carried out from 2008 to 2012 in twelve industrial banana plantations in Ivory Coast. The evaluation of the phytosanitary status focused on the environmental characteristics (grassing control, moisture management and plot borders) and on the organization of the phytosanitary teams. The results showed that the Eglin plantations in Agboville, Azaguié and Motobé; WANITA Dabou presented an acceptable sanitary state, with a clear progression of the observed environmental parameters. As for the TIABAM, Rouchard Tagbadié, CDBCI Azaguié and SAKJ Aboisso plantations, they showed concern in the recovery of the sanitary state of their plots. As of 2010, all plantations had the presence of phytosanitary teams who digitized the observations of the disease and regularly monitored the evolution of the disease. All the plantations showed a positive evolution in taking into account the essential parameters for an efficient management of black Sigatoka

Effet de Différentes Doses d’Engrais Minéraux sur le Rendement de deux Variétés de Patate Douce [Ipomoea batatas (L) Lam] à Bouaké, Centre de la Côte d'Ivoire

L'étude a été conduite sur deux campagnes (2015/2016 et 2016/2017) afin d’évaluer l’effet de l’apport d’engrais minéraux (NPK 15-15-15 et 12-22- 22) sur le rendement de deux variétés de patate douce à Bouaké. L’essai a été conduit selon un dispositif expérimental split-plot comportant deux variétés de patate douce (Tib-440060 et Irene) et cinq niveaux de fertilisation (0, 200, 300, 400, 500 kg/ha) en trois répétitions. Les résultats ont montré que les engrais minéraux ont eu un effet positif sur les composantes du rendement des racines tubéreuses. Les résultats de l'étude ont également montré que l'apport d'engrais minéraux n’a pas modifié les paramètres organoleptiques mesurés à savoir le goût, l’aspect, la cuisson et la contenance en eau de la patate douce. La variété Irene semble plus s’accommoder à la fertilisation minérale par rapport à la variété Tib-440060. The study was conducted over two seasons (2015/2016 and 2016/2017) to assess the effect of mineral fertilizer inputs (NPK 15-15-15 and 12-22-22) on the yield of two sweet potato varieties in Bouaké. The test was conducted using a split-plot experimental design with two varieties of sweet potato (Tib-440060 and Irene) and five levels of fertilization (0, 200, 300, 400, 400, 500 kg/ha) in three repetitions. The results showed that mineral fertilizers had a positive effect on the yield components of tuberous roots. The results of the study also showed that the use of mineral fertilizers did not modify the organoleptic parameters measured, namely the taste, appearance, cooking and water content of the sweet potato. Irene variety seems to be more suited to mineral fertilization than the Tib-440060 variety

Effet de la Période de Pollinisation Manuelle sur la Fructification de l’igname (Dioscorea rotundata Poir; Dioscoreaceae) en Côte d’Ivoire

D. rotundata is the most popular species among consumers in Côte d'Ivoire. However, its production is stagnating due to the many constraints associated with its cultivation, particularly virus diseases. The use of improved varieties from sexual reproduction could effectively contribute to sustainable production. This work aimed to evaluate the crossing period in order to increase fruiting rates in this species. A total of 28 intra-specific crosses were carried out using 4 female and 7 male clones from the CNRA-Bouaké yam collection. Two time slots H1 (from 7:30 to 11:00) and H2 (from 11:00 to 13:30), selected for crossings, were compared to determine the optimal pollination period. Out of 30061 pollinated flowers, 2249 fruits were obtained i.e 7.48% with a variation range from 1.16 to 51.06% as the average fruiting rate depending on the clone combinations. Fruiting rates were significantly higher in H1 (8.53%) compared to 6.22% in H2. The female clone, Cnraigr09/00001, has recorded the highest fruiting rate especially in H1 (18.10%). Similarly, the male clones CIVCDr072, TDr00/00380 and TDr95/18555 have got the highest rates in H1 with 9.3; 9.8 and 16.3% respectively compared to those in H2. The couple Cnraigr09/00001 x TDr99/18555 recorded fruiting rates of 35.41% and 8.78% statistically different at schedule H1 and H2, respectively. A strong variation in the fruiting rate in favor of the H1 schedule was obtained between the different clone combinations.L’igname D. rotundata est l’espèce la plus appréciée des consommateurs en Côte d’Ivoire. Cependant, sa production stagne du fait des nombreuses contraintes liées à sa culture notamment les viroses. L’utilisation de variétés améliorées issues de reproduction sexuelle, pourrait contribuer efficacement à une production durable. Ce travail visait à évaluer la période des croisements afin d’accroitre les taux de fructifications chez cette espèce. Au total, 28 croisements intra-spécifiques ont été réalisés en utilisant 4 clones femelles et 7 clones mâles issus de la collection d’ignames du CNRA-Bouaké. Deux plages horaires H1 (de 7h30 à 11h) et H2 (de 11h à 13h30), retenues pour les croisements ont été comparées en vue de déterminer la période optimale de pollinisation. Sur 30061 fleurs pollinisées, 2249 fruits ont été obtenus soit 7,48% avec une variation allant de 1,16 à 51,06% de taux moyen de fructification selon les combinaisons de clones. Les taux de fructifications ont été significativement plus élevés en H1 (8,53%) contre 6,22% en H2. Le clone femelle, Cnraigr09/00001 a eu le taux de fructification le plus élevé et spécialement en H1 (18,10%). De même les clones mâles CIVCDr072, TDr00/00380 et TDr95/18555 ont eu les meilleurs taux en H1 avec respectivement 9,3 ; 9,8 et 16,3% par rapport à H2. Le couple Cnraigr09/00001 x TDr99/18555 a donné des taux de fructifications 35,41% et 8,78% statistiquement différents aux horaires H1 et H2, respectivement. Une forte variation du taux de fructification en faveur de l’horaire H1 a été obtenue entre les différentes combinaisons de clones

Yam Cropping System in Cote d’Ivoire: Current Practices and Constraints

Yam is the first food crop in Côte d'Ivoire. It is being cultivated under a traditional technique system with low output. Detailed profiling of the current practices and opportunities for improvement is essential to increase the benefits of yam for food security and income in the country. This study diagnosed the current practices, constraints, and requirements in order to gain insight on the yam cropping system for research and development in Côte d'Ivoire. The surveys were conducted in seven (7) regions in the main yam production area. Groups of 60 producers per region were investigated. Individual surveys were also conducted on-farm, particularly for diagnosing the physical environment and yam-based production systems. As results, yambased production systems are characterized by mixed cropping (cassava, corn and vegetable crops) and/or rotation with various other crops (rice, groundnut, vegetable crops, …). Preferred plots for yam cultivation are forest, savannah or fallow areas. The major constraints in yam cultivation were the effects of environmental stresses, labor scarcity, pest damage, tuber and seed storage difficulties as well as the low market value of yam. The most cultivated yam varieties are Bètè-Bètè and Florido for Dioscorea alata and Lokpa for Dioscorea rotundata. The cropping system, the species and varieties vary according to the region, the topo sequence and the type of soil. Knowledgebuilding that take into account constraints related to yam cultivation, for each production area, can serve as guidance for variety breeding and cultivation environment redefinition

Participatory selection of orange-fleshed sweetpotato varieties in north and north-east Côte d’Ivoire

Sweetpotato is cultivated in all the regions of Côte d’Ivoire for consumption and as a source of income. Only varieties with white or yellow flesh are grown. Production of nutritious orange-fleshed sweetpotato (OFSP) is hampered by the lack of genetic resources and planting material. To evaluate and release OFSP varieties, on-farm demonstration tests were conducted with women farmer groups in Bondoukou, Nassian, Korhogo and Bondiali in the north and northeast Côte d’Ivoire. Six varieties- ‘Kabode’, ‘Kakamega7’ (‘Irene’), ‘Tacha’, ‘Bela Bela’, ‘Vita’ and TIB-440060-were evaluated in comparison with locally grown varieties. The on-farm demonstration was laid out in a randomised complete block design with replicated three times per location. Assessments were made on yield, disease and pests; and consumer preference on attractiveness of skin color and flesh of the root (fresh and boiled), taste, texture and starchiness. Results showed that introduced varieties have generally recorded higher yields than the local varieties: Yields of about 25 t/ha have been recorded on the sites. The best average yield of about 15 t/ha, was recorded for TIB-440060 and ‘Irene’ varieties. Farmers’ acceptance of OFSP varieties based on the attraction of their color, the dry matter content and taste was more than 90%. At the end of the sensory tests, ‘Irene’, which achieved the best compromise between all observed and measured parameters, was most appreciated and was the farmers’ first choice, followed by varieties TIB-440060 and ‘Bela bela’

Starch granule size and shape characterization of yam ( Dioscorea alata L.) flour using automated image analysis

International audienceAbstract BACKGROUND Roots, tubers and bananas (RTB) play an essential role as staple foods, particularly in Africa. Consumer acceptance for RTB products relies strongly on the functional properties of, which may be affected by the size and shape of its granules. Classically, these are characterized either using manual measurements on microscopic photographs of starch colored with iodine, or using a laser light‐scattering granulometer (LLSG). While the former is tedious and only allows the analysis of a small number of granules, the latter only provides limited information on the shape of the starch granule. RESULTS In this study, an open‐source solution was developed allowing the automated measurement of the characteristic parameters of the size and shape of yam starch granules by applying thresholding and object identification on microscopic photographs. A random forest (RF) model was used to predict the starch granule shape class. This analysis pipeline was successfully applied to a yam diversity panel of 47 genotypes, leading to the characterization of more than 205 000 starch granules. Comparison between the classical and automated method shows a very strong correlation ( R 2 = 0.99) and an absence of bias for granule size. The RF model predicted shape class with an accuracy of 83%. With heritability equal to 0.85, the median projected area of the granules varied from 381 to 1115 μm 2 and their observed shapes were ellipsoidal, polyhedral, round and triangular. CONCLUSION The results obtained in this study show that the proposed open‐source pipeline offers an accurate, robust and discriminating solution for medium‐throughput phenotyping of yam starch granule size distribution and shape classification. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry

Advancing breeding for climate‐resilient yam production in Côte d'Ivoire

International audienceThe anticipated twofold increase in C & ocirc;te d'Ivoire's population within the next three decades poses a significant challenge for agricultural research to sustain food security. Despite being an under-researched and often neglected crop, yam remains the primary staple food and a crucial source of income in the country. With an annual estimated market value of over 2000 billion CFA francs, yam ranks among the top five most economically valuable crops in C & ocirc;te d'Ivoire. For the past 15 years, yam production has experienced a decline in productivity, which has been compensated for by expanding the cropped area. Unfortunately, this approach exacerbates the risk of deforestation and soil degradation. Additionally, the impact of climate change on yam production, coupled with a lack of financial resources to address it, has rendered this unsustainable mode of production even more precarious. The purpose of this study is to provide an overview of the effects of climate change on yam production in C & ocirc;te d'Ivoire. We investigated the reasons for the productivity decline and described the risks on food security. Furthermore, we explained how varietal innovation of Dioscorea alata could play a critical role in mitigating these effects and outlined related research avenues that need to be explored. To help policymakers and research programme directors justify the importance of this agenda, this article presents the main arguments in favour of a substantial investment in adapting yam production to the global changes affecting Cote d'Ivoire

Sweetpotato cultivation: characteristics, constraints and preferred traits of producers and consumers in Côte d'Ivoire

International audienceAbstract Background In an environment where the adoption of improved varieties resulting from plant breeding programs is limited, it is essential to identify end‐user preferences beforehand. A participatory survey was conducted in eight localities in Korhogo and Bouaké regions (central and northern Cote d'Ivoire respectively) to identify producers' preferences and increase the adoption of improved varieties. The study involved 160 producers and consumers through focus group discussions and individual interviews. Results Sweetpotato is mostly grown on small plots (<1 ha) of land (89.2%), with women (66%) as the main producers. In the Bouaké region, sweetpotatoes are grown on mounds (100%), whereas in Korhogo they are grown on ridges (86.2%). The main food products or forms of preparation from roots are fries (34.7%), boiled (34.3%), mashed (12.4%), and sweetpotato stew (9.1%). Major constraints, including low price of roots (26.3%), low productivity (16.2%), and post‐harvest storage issues (14.5%), were identified as affecting sweetpotato production. Conclusions The selection of new varieties should be oriented towards high‐yielding varieties with high dry matter content, deployed stems, and roots of round, oblong, or elliptical shape with good culinary characteristics (dry matter, sweet taste, dry texture, absence of fiber). Plants must be drought resistant, be tolerant to poor soil, diseases, and pests, and have a good yield. The color of skin and flesh of the sweetpotato, although constituting criteria of choice, are not essential for the acceptance or the rejection of a variety by users. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry

Diversity of Water Yam (<i>Dioscorea alata</i> L.) Accessions from Côte d’Ivoire Based on SNP Markers and Agronomic Traits

Dioscorea alata (L.), also referred to as water, winged, or greater yam, is one of the most economically important staple food crops in tropical and subtropical areas. In Côte d’Ivoire, it represents, along with other yam species, the largest food crop and significantly contributes to food security. However, studies focusing on better understanding the structure and extent of genetic diversity among D. alata accessions, using molecular and phenotypic traits, are limited. This study was, therefore, conducted to assess the pattern of genetic variability in a set of 188 D. alata accessions from the National Agronomic Research Centre (CNRA) genebank using 11,722 SNP markers (generated by the Diversity Arrays Technology) and nine agronomic traits. Phylogenetic analyses using hierarchical clustering, admixture, kinship, and Discriminant analysis of principal component (DAPC) all assigned the accessions into four main clusters. Genetic diversity assessment using molecular-based SNP markers showed a high proportion of polymorphic SNPs (87.81%). The analysis of molecular variance (AMOVA) showed low molecular variability within genetic groups. In addition, the agronomic traits evaluated for two years in field conditions showed a high heritability and high variability among D. alata accessions. This study provides insights into the genetic diversity among accessions in the CNRA genebank and opens an avenue for sustainable resource management and the identification of promising parental clones for water yam breeding programs in Côte d’Ivoire