Caractérisation botanique et agronomique de trois espèces de cucurbites consommées en sauce en Afrique de l'Ouest : Citrullus sp., Cucumeropsis mannii Naudin et Lagenaria siceraria (Molina) Standl

Botanical and agronomical characterisation of three species of cucurbit consumed as sauce in West Africa: Citrullus sp., Cucumeropsis mannii Naudin and Lagenaria siceraria (Molina) Standl. There are in Côte d'Ivoire at least five species of cucurbit incorrectly called ""pistaches"" in town and cultivated at small scale by women for their oleaginous seeds that are a great importance in the sociocultural live of several peoples. Nevertheless, few studies aimed at the improvement of these plants (related notably to taxonomy, genetic resources collecting missions, genetic characterisation, agronomic evaluation, and selection) have been carried out. In order to set up a list of reliable traits that should be examined easily during and after collecting missions, we carry out in the present study, for three species (Citrullus sp., Cucumeropsis mannii Naudin and Lagenaria siceraria (Molina) Standl) a botanic description and an analysis of eleven agronomic traits: 100-seeds weight, germination rate, seedlings emergence time, matured fruit weight, matured fruit decomposition time, mean number of seeds per fruit, seeds shape, fruit diameter, fruit interior cavity diameter, flowering time, and fruiting time. Statistical analyses using nine of these traits showed that the three species can be completely distinguished with six traits whereas the three other traits allowed partial distinction. Low yields have been observed for the three species: 11.41 kg/ha of decorticated seeds for C. mannii, 18.51 kg/ha for Citrullus sp. and 75.14 kg/ha for L. siceraria. From the observed yield components, the possibilities to improve the production of these cucurbits are discussed

Estimation du nombre de greffons produits par l’anacardier (Anacardium occidentale L.) : influence du genotype du porte-greffe et des parametres architecturaux

La demande en plants greffés des clones hauts producteurs d’anacardier (Anacardium occidentale L.), s’accroît au fil des années. Afin de mieux planifier la fourniture de plants greffés et satisfaire la demande, il s’avère nécessaire de mettre au point une méthode simple de détermination de la quantité maximale de greffons et de plants susceptibles d’être produits au cours d’une année. A cet effet, l’architecture des anacardiers issus du greffage du clone haut producteur LAX3264 sur trois porte-greffes a été étudiée. Les résultats ont révélé deux types d’architecture, semi-érigée ou érigéeouverte selon le génotype du porte-greffe. Ces deux types d’architecture n’influencent pas significativement la majorité des paramètres évalués. En revanche, le diamètre à 10 cm du sol et l’envergure moyenne de la plante greffée ont varié significativement selon le génotype du porte-greffe. Quel que soit le génotype du porte-greffe et le type d’architecture, l’envergure moyenne de la plante est un estimateur efficace du nombre de greffons produits par l’anacardier greffé. L’équation d’allométrie est de type : Y= 162,4755X-376,9773. Ainsi, cette étude a permis de mettre au point une méthode simple et fiable d’estimation du nombre de greffons par plante. Mots clés: Anacardier ; architecture ; envergure ; greffons, équation d’allométrie English Title: Estimate of the number of grafts produced by the cashew tree (Anacardium occidentale L.): influence of the genotype of the rootstock and architectural parameters English Abstract The demand for grafted seedlings of the high-producing clones of cashew tree (Anacardium occidentale L.), has increased over t he years. In order to better plan the supply of seedlings and meet the producer’s request, it proves to be necessary to develop a simple method for estimating the maximum quantity of scions and seedlings likely to be produced during one year. For this purpose the architecture of the cashew trees resulting from the grafting of the high-producing clone LA X3264 on three rootstocks was studied.The results showed two types of architecture, semi-erected or openerected, depending on the rootstock genotype.These two types of architecture did not influence significantly the parameters assessed. By contrast, the diameter at 10 cm from the ground and the average span of the grafted plant varied significantly according to the genotype of the rootstock. Whatever the genotype of the rootstock and the type of archi-tecture, the average plant span was an effective estimator of the scions produced by the grafted cashew tree. The allometric equation found was : Y=162.4755X-376.9773. Thus, this study provided a simple and reliable method for estimating the number of scions of grafted cashew tree. Keywords : Cashew tree ; architecture ; span ; scions, Allometric equatio

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)

peer reviewe

Genetic characterization of oleaginous bottle gourd (Lagenaria siceraria) germplasm from Côte d'Ivoire using agromorphological and molecular markers

Being difficult to regenerate and maintain the seeds, the oleaginous bottle gourd was investigated using nine agromorphological traits and 31 amplified fragment length polymorphism (AFLP) markers. Specifically, the study was conducted to determine the intra-specific variability of a total of 173 accessions, which were identified from five agro-ecological regions from Côte d'Ivoire (Centre, East, North and South). Then, the genetic diversity and relationships within accessions were studied using AFLP markers. This characterization using both morphological and AFLP markers was realized in order to ultimately build a reliable core collection. The discriminant analysis, using nine quantitative traits, reveals plant length and seeds number per fruit as discriminating characteristics. From the accessions used for the agromorphological study, 148 were able to be differentiated by the AFLP markers. A range of 52 to 113 bands were amplified per primer combination. As revealed by the analysis of molecular variance (AMOVA), 28% of the total variation resides among accessions and 72% occurs within populations. The AMOVA computed in order to differentiate cultivars, displayed the same trends when no prior grouping of accessions was considered. The differentiation within cultivar (97%) was more than that, among cultivars (3%). Tree topologies inferred by neighbour-joining analysis reflected no clear cut off grouping

Vermicompost utilization: A way to food security in rural area

The increase in agricultural production as well as its nutritional quality at a cost bearable by producers is today a challenge in rural areas. Vermicompost is a low-cost organic amendment known for its effectiveness on agricultural productivity increase but little is diffused about its efficacy on nutritional quality. This study aimed to evaluate the benefits of vermicompost from cattle dung on Lagenaria siceraria yield and its edible parts content in mineral and in heavy metal compared to raw dung. The study was carried out in the region of Mankono the biggest area for L. siceraria production in Côte d’Ivoire during three cycle seasons. The experiment consisted of three treatments arranged in a complete randomized block design with four replicates. The agronomic parameters as yield, number of leaves and flowers per plant were evaluated. Also, mineral nutrients and heavy metal concentrations in roots, leaves and seeds were measured. Results showed that yield, number of leaves and flowers per plant were higher with the vermicompost than with the cattle manure and the control. The yield obtained with the vermicompost was 2.5 times and 20 times higher respectively than that with the cattle manure and the control. Mineral concentrations in roots, leaves and seeds were the highest with the vermicompost when heavy metal contents were the lowest. The present study indicates that vermicompost utilization improves the yield and the nutritional quality of the edible parts of L. siceraria and hence could be recommended to producers for increasing productivity with keeping the health and safety of human

Microsatellite-based genetic diversity among accessions of Citrullus spp. collected from 36 countries

Watermelon (Citrullus lanatus) is one of the most economically important vegetable cucurbits. However, the genetic and taxonomic statuses of its closely related species remain scantly documented, limiting their full use for agronomic purposes. The genetic diversity and structure of 74 accessions covering 47 dessert type (C. lanatus subsp. vulgaris), 21 oilseed type (C. mucosospermus), and 6 citron melon (C. lanatus subsp. lanatus var citroides) collected from 36 countries throughout 4 continents, were analyzed using 18 polymorphic SSR markers. The mean values of proportion of polymorphic loci (P = 29.73), number of alleles per locus (A = 1.243), effective number of alleles per locus (Ae = 1.153) Shannon index (I = 0.191), observed and expected heterozygosities (Ho = 0.124; He = 0.149) confirmed the narrow genetic basis of C. lanatus. According to molecular variance analysis the most important component of the genetic variation was obtained among accessions (70%). On the contrary, lower genetic variation was noted among species (16%), countries (37%), and continents (14%). It is suggested that the cultivated forms of Citrullus spp. originated from or successive selection cycles aimed at few and/or common traits, in few ancestral populations. Clustering based on both Bayesian approach and an unweighted pair group method with arithmetic mean pointed out three groups of accessions corresponding to use types and collecting countries. Based on these results, future collecting missions could be focused mainly on representative ecological sites in Citrullus spp. distribution areas, and increasing the number of accessions and seeds per accession