Observations préliminaires de la variabilité entre quelques morphotypes de voandzou (Vigna subterranea L. Verdc., Fabaceae) de Côte d'Ivoire

Preliminary observations of variability between some morphotypes of bambara groundnut (Vigna subterranea L. Verdc., Fabaceae) from Côte d’Ivoire. Bambara groundnut (Vigna subterranea L. Verdc.), is a food legume mainly cultivated by women for whom it represents a source of income for the household. In Côte d’Ivoire, the cultivation of bambara groundnut is located in the western and northern parts of the country. These zones are characterised by contrasted agroecology including tropical rain forest and dry savanna. In these zones, bambara groundnut plays a key role in both food and culture of peoples. Four morphotypes of Côte d’Ivoire (ICU, BPR, RBU, NFU) were used in a preliminary study to assess the phenotypic variability between morphotypes. For each morphotype, 100 individuals were sampled to analyse 26 agromorphological traits selected from the list of bambara groundnut descriptors. Results of statistical analyses showed an important variability among morphotypes suggesting that 22 of these characters could be powerful to distinguish diversity among bambara groundnut morphotypes of Côte d’Ivoire. Three morphotypes (ICU, BPR and RBU) show a shorter reproductive cycle than the other (NFU). In our experimental conditions, morphotypes with a shorter reproductive cycle give a higher percentage of matured pods (87 to 95%), compared to morphotype NFU (60%). The morphotype ICU was particularly earlier, maturing 90 days after sowing (DAS), whereas the long reproductive cycle morphotype (NFU) required about 137 days. Based on the analysed agronomic traits, possibilities to improve bambara groundnut yield and to promote its cultivation in Côte d’Ivoire are discussed

Effet de la Saison de Culture et de la Densité des Plants sur les Adventices et la Production de la Cucurbite oléagineuse Citrullus lanatus (Thunberg) Matsum. & Nakai (Cucurbitaceae)

Citrullus lanatus a été cultivée sur 2 périodes de l’année (saison 1 : d’Avril à Juillet et saison 2 : de Septembre à Décembre 2006) à la ferme expérimentale de l’Université d’Abobo-Adjamé en Côte d’Ivoire. Ces études visaient à déterminer la densité de la cucurbite qui assure un contrôle biologique des adventices et celle qui permet une meilleure productivité de cette culture mineure. Le dispositif expérimental est un bloc complètement randomisé, subdivisé en parcelles élémentaires de 6 m × 6 m avec trois répétitions par traitement. Sept paramètres agronomiques chez la cucurbite et la densité d’adventices (estimée uniquement au cours de la 1ère saison) ont été analysés dans trois systèmes culturaux. L’analyse a été suivie de tests de comparaisons multiples. Il en ressort que l’augmentation de la densité de la cucurbite réduit le nombre d’adventices. Les résultats montrent également que les composantes de rendement de la cucurbite, excepté le nombre de fruits à l’hectare (NFHa), diminuent avec la densité de semis. Cette diminution est plus prononcée à la deuxième saison. Sur la base des résultats obtenus, il a été suggéré de cultiver C. lanatus, à forte densité pour lutter contre les adventices et à faible densité pour obtenir des effets bénéfiques au niveau de son rendement.Mots-clés : Citrullus lanatus – densité – adventives – rendement

Optimization of ISSR marker for African edible-seeded Cucurbitaceae species’ genetic diversity analysis

We applied a molecular approach using inter-simple sequence repeat (ISSR) markers on three African edible-seeded cucurbits (Citrullus lanatus L. Matsumura and Nakai, Cucumeropsis mannii L. Naudin and Cucumis melo var. agrestis L. Naudin). To obtain clear and reproducible bands on 1.5% agarose gels, we screened 21 ISSR primers and three parameters (annealing temperature, gel tray, and voltage and running time). The resolution of 11 ISSR markers was performed, with optimal annealing temperature (Ta) varying from 50 to 52°C. The best combination to obtain clear and well-distinguished band patterns was 1.5% agarose gel with a 20-lanes tray (6 mm width) at 80 V for 5 h. Applying the 11 ISSR primers on DNA extracted from an accession of C. lanatus, 66 bands with 4 to 11 bands per primer was observed.Keywords: ISSR, Cucurbits, genetic diversity, molecular markers, optimizatio

Evaluation de la diversité agromorphologique des descendances hybrides de cocotier (Cocos nucifera L.) Nain Jaune Malaisie x Grand Vanuatu en Côte d’Ivoire

Ce travail vise à évaluer la diversité agromorphologique des descendances hybrides de cocotier Nain Jaune Malaisie x Grand Vanuatu tolérants à la maladie du jaunissement. Les observations ont porté sur 30 descripteurs liés aux stipes, feuilles, inflorescences et fruits. Les résultats montrent que 12 descripteurs permettent de discriminer les individus au niveau inter et intra-descendance. La structuration de ces descendances a révélé deux groupes. Il s’agit des descendances d15 qui se sont distinguées des autres. Les arbres de la descendance d15 sont caractérisés par une Circonférence du stipe à 20 cm du sol (134,52 cm), un Epaisseur de Pétiole (3,25 cm), une Largeur de Foliole (6,42 cm), un Nombre d’Epillets (40), un Nombre d’Epillet Sans Fleur femelle (23), un Diamètre polaire de la noix (20,03 cm) et une masse de la bourre (291,82 g) supérieures à ceux des autres descendances. Le Géniteur G15 qui donne des descendances robustes et présentant des aptitudes favorables à une bonne production est à sélectionner pour produire des hybrides NJM x GVT tolérants et haut producteurs.Mots clés: Cocotier, hybride, jaunissement mortel, diversité agromorphologique

Bases génétiques et biochimiques de la capacité germinative des graines: implications pour les systèmes semenciers et la production alimentaire

Une bonne semence est essentielle pour une agriculture productive. Les attributs de qualité de la semence incluent les paramètres génétiques, physiques, physiologiques et les conditions sanitaires. Ces attributs donnent des informations utiles sur la capacité germinative de la semence, la rapidité de l’émergence des plantules et leur capacité à établir des plantes vigoureuses et productives. Une des qualités majeures de la semence, est sa capacité germinative ou le potentiel de la semence à germer et a produire des plantules vigoureuses dans les conditions favorables. La capacité germinative est sous le contrôle de plusieurs facteurs intrinsèques et environnementaux. Des travaux de recherche menés sur des graines de plusieurs espèces ont identifié, au titre des causes intrinsèques, des facteurs biochimiques et génétiques impliqués dans la capacité germinative de la graine. La connaissance de ces facteurs est utile pour la production agricole à travers l’amélioration des conditions de conservation des semences et la mise en place de systèmes semenciers efficaces. Cet article fait une synthèse de ces travaux de recherche et discute de la relation entre capacité germinative des graines et sécurité alimentaire.Mots clé: Semence, capacité germinative, facteurs biochimiques, gènes, systèmes semenciers, sécurité alimentair

Etude de la filière rotin dans le district d'Abidjan (Sud Côte d'Ivoire)

Study of rattan production-to-consumption system in the district of Abidjan (South Côte dIvoire). The domestication of Non-Wood Forest Products (NWFP) requires an evaluation of their social and economical potentials in the target zones. The present work deals with this problematic in the district of Abidjan (South Côte dIvoire) in order to suggest for this zone, a community-based forest management plan, allowing a conservation and sustainable exploitation of rattan, used as plant model. From interviews and printed forms addressed to 42 rural families composed of about 200 persons, 30 rattan collectors, 12 rattan raw stems traders, 187 craftsmen distributed among 60 workroom and ten urban families (about 70 persons) we determine the commercial channels and evaluate the economic profit of rattan exploitation for each social category involved. We also note the different problems encountered by rattan operators. Data show that rattan trade is profitable at both rural and urban levels, suggesting that this plant should be a NWFP biological model for the implementation of rural forests management and sustainable exploitation program. Then we showed that the exploitation of 250 bunches used for furniture production generated a global income equalled 2830 or 2877 US $according to harvester (farmer or collector from town). Of this global income, 375US$ (13.03%) are owned by farmers, 696 (24.59%) by harvesters, 929 (32.39%) or 561 (19.82%) by canes wholesalers, and 1573 (54.67 or 55.58%, according the case) by craftsmen. Nevertheless, many legislative, institutional, and logistic constraints threat presently the stability and expansion of rattan industry. From obtained data, suggestions are made either for forests management and sustainable exploitation strategies and a best organisation of rattan channels

Effet des dates de semis sur la performance agronomique de Lagenaria siceraria (Molina) Standl. (Cucurbitaceae) et Manihot esculenta Crantz (Euphorbiaceae) en culture associée

Effect of sowing dates on the agronomic performance of the intercrops: Lagenaria siceraria (Molina) Standl. (Cucurbitaceae) and Manihot esculenta Crantz (Euphorbiaceae). Description of the subject. The intercropping system is a beneficial method, which is widely used in tropical areas for sustainable soil fertility management, and has been found to improve both the yields of traditional agriculture and the income of small producers. Objectives. The aim of this study was to compare and evaluate the effect of associated culture and pure culture of cucurbit Lagenaria siceraria creeping plant and the variety of cassava Manihot esculenta var. 'Bonoua Blanc' upright plant on the agronomic performance of each crop. Method. An experiment was established in randomized complete block design with three replicates per treatment. The treatments compared were firstly, associated crops M. esculenta var. 'Bonoua Blanc' / L. siceraria with cucurbit seedlings at 0 days (CAT0), 15 days (CAT15), 30 days (CAT30) and 45 days (CAT45) after cassava; secondly, pure cultures of cucurbit on the same dates as for associated crops (CPT0, CPT15, CPT30 and CPT45), and thirdly, a pure culture of cassava at 0 days (CP). Nine agronomic characteristics were analyzed in cucurbit and eight in cassava. Results. The agronomic parameters evaluated were the yield components of cassava, which varied with the increase in seedling time of cucurbit. However, the performance of cucurbit decreased with the increase in seedlings either in the associated crop or in pure culture. Performance also decreased sharply for the same sowing dates in pure culture. Despite high productivity when cucurbit was simultaneously planted with cassava, it remained low compared to the cucurbit pure crop. Conclusions. Intercropping of cucurbit L. siceraria and cassava M. esculenta was not found to be beneficial to the yield of the individual crops. However, the use of cucurbit as an intercropping cover crop helps to conserve soil moisture and to manage arable land and weeds for the benefit of cassava crops

Determination of a Suitable Protocol for Indigenous Oilseed Cucurbits Plant Regeneration

The present work was carried out to establish rapid in vitro propagation of the indigenous oilseed Citrullus lanatus. Efficiency of 3 protocols for seed decontamination was investigated. High level of seed sterilization was obtained after removing seed coat and soaking the seeds in 1.6% sodium hypochlorite with a drop of Tween 20. Shoot tips, single node and cotyledon explants of 3 morphotypes have been screened for adventitious shoot formation in tissue culture. Best response in terms of multiple shoot induction was obtained from cotyledon proximal part with hypocotyl segment on Murashige and Skoog medium supplemented with 1 mg/l 6-Benzylaminopurine, 30 g/l sucrose and 8 g/l agar. After 3 weeks of culture, 90% of cotyledon proximal parts induced shoot. An average of 12.6 shoots per explant and a mean shoot length of 8 mm were obtained after multiplication stage. Shoot induction appeared to be strongly influenced by genotype and explant type. The percentage of shoot induction from cotyledon proximal parts ranged from 23.3% to 64.0% according to the genotype. Efficient rooting was achieved on half-solid MS medium containing 0.1 mg/l 1-Naphthaleneactic acid or without growth regulator. Acclimatised plantlets were transferred to greenhouse where they grew and flowered like seeded plantlets

Morphological and allozyme variation in a collection of Lagenaria siceraria (Molina) Standl. from Côte d'Ivoire

This study describes the intraspecific variation of 30 edible-seed Lagenaria siceraria germplasm accessions from the University of Abobo-Adjamé. These accessions were collected from three (Centre, East and South) geographical zones of Côte d’Ivoire. Selection based on seed size by the farmers has resulted in subdividing the species into two cultivars: large-seeded and smallseeded. The morphological diversity study of the collection included 18 accessions and 24 traits. The multivariate analysis of variance (MANOVA) showed a significant difference between the two groups of cultivars. Principal component analysis on 13 traits pointed out variations among individuals, mainly on the basis of flower, fruit, and seed size. Dendrogram with UPGMA method allowed clustering of the cultivars. The genetic structure analysis among accessions using allozyme markers showed the following values: 18.95% for the proportion of polymorphic loci (P), 1.21 for the number of alleles (A) and 0.053 for observed heterozygosity (Ho). The level of the within accessions genetic diversity (HS = 0.188) was higher than the genetic variation among accessions (DST = 0.082). The estimates of F-statistics indicated a low level of genetic differentiation between accessions (FST = 0.298). Such a value suggested that L. siceraria maintains about 30% of its genetic variation among accessions. Nei genetic distances between the two cultivars were also low (0.002), indicating that cultivars were genetically similar enough to belong to the same genetic group

Existing competitive indices in the intercropping system of Manihot esculenta

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