Search

Description of the subject. Cashew was introduced to Côte d'Ivoire in 1951 to control erosion and reforest cutover lands. From 1972 to 1980, natural forest plantations were converted to fruit orchards and were supplemented by the ‘Jumbo’ cashew variety imported from Brazil. Germplasm expeditions conducted in 2010 and 2014–2015 identified 209 high-yielding cultivars in the major cashew growing areas of Côte d’Ivoire. Although the morphological characteristics of these cultivars have been assessed, little is known about the genetic diversity and genetic structure of the germplasm collection. Objectives. The objective of the study was to evaluate the genetic diversity of high-yielding cashew cultivars for better use in breeding programs. Method. We performed DNA isolation using Qiagen DNeasy Plant Mini Kits and PCR analysis with 18 SSR markers. Results. We identified the first two introduced populations of cashew in Côte d’Ivoire. The average allelic richness is 3.56 (± 1.45) alleles per locus, the fixation index (FIS) indicates an overall heterozygosity deficit of 0.332 (± 0.076), and the average population differentiation (FST) is 0.014 (± 0.004). Much of the total genetic variability occurs at the intra-population level (98.6%), compared to only 1.4% variability attributable to differences between populations. Average value of gene flow is 22.528. Conclusions. Gene flow within cashew populations maintains high intra-population genetic diversity. This flow rate reflects a long-term exploitable genetic variability for use in selection and conservation.

Cocoa Expansion Dynamics in the Forest-Savanna Contact Zones: Case Study of the Sub-prefecture of Kokumbo (Côte d'Ivoire). In Ivory Coast, forests-savannah transition areas have been considered from the 1970s as unfavorable to cocoa cultivation. In recent years, however, there has been a comeback to the cocoa economy in these areas. This study carried out in the sub-prefecture of Kokumbo, aimed to map and to follows the spatial and temporal evolution of this crop using Landsat images of 1990, 2002 and 2016. In order to better understand the fundamentals of the peasant practices, surveys were carried out in different villages in the area. Treatment shows that the influence of cocoa culture is becoming increasingly important in the region. This cocoa crop is set up to the detriment of forests and savannahs, which have lost 25% and 58.1% of their initial area respectively. The surveys identified four types of cocoa farms, of which 65% of the plots were created between 2002 and 2014. Facing this relatively recent expansion, the issue of the sustainability of cocoa production systems in this region arises. Their agronomic and economic performances and their value for biodiversity conservation should be analyzed in future studies.

Dynamics of Infestation in the Sanaimbo Protected Forest by Weeds from Surrounding Agro-ecosystems. The infestation dynamics of the Sanaimbo Protected Forest by weeds was evaluated with the aim to quantify the impact of weeds on the original flora of this locality. Floristic and phytosociological surveys samples were carried out on plots located inside and outside the forest. The frequency and proportion of biological types is different in plots located outside and within the classified forest. Chromolaena odorata (L.) King & H.E. Robins has a high degree of infestation whatever the plot location. Euphorbia heterophylla L., Ageratum conyzoides L. and Panicum laxum Sw. show high levels of infestation in the plots out of the forest and start invading slowly the plots within the forest.

Effects of the Association of Compost and Mineral Fertilizer on the Productivity of Cotton and Maize Cropping System in Burkina Faso. To improve the productivity of a cotton - maize rotation using organic and mineral fertilization, a study was carried out in experimental station from 2008 to 2010. Five levels of compost (0, 2, 6, 9 and 12 t of dry matter ha­1) combined to four rate of mineral fertilizer were compared in split­plot statistical design. The physical and chemical characteristics of soil, crop yields, as well as the mineral nutrition of maize and cotton plants were evaluated. The results show that the content of assimilable P and available K was significantly improved in amended soils by compost which had no significant effect on the carbon content. In amended soils, compost improved plants nutrition which was correct in nitrogen and potassium for cotton and deficient in nitrogen and phosphorus for maize. Compared to control soil, compost combined to mineral fertilizers increased significantly yields with a better efficacy for the recommended mineral manure. The application of 2 t ha­1 of compost per year was as effective as high doses of compost in the second year, and more effective than the latter in the third year. An economy on the recommended dose of mineral fertilizer could be considered, with an annual input of 2 t ha­1 of compost to the mineral fertilizers necessary to maintain the productivity of the cotton­cereal cropping systems.

Studies of some Parameters of Growth and Nutritive Values of Snail Varieties Archachatina marginata (Swainson) Bred in Natural Environment. Approximately two months old juvenile snails of from black and white body varieties Archachatina marginata obtained from indoor rearing were introduced in Banco forest of Nangui Abogoua University in order to study some growth and nutritive values parameters after 24 months. The result obtained showed that 12% of black body snails exhibited average shell length of 12.5 cm with 218.19 and 44.57 average live weight respectively. Concerning white body snails, only 3% exhibited average shell length of 12.5 cm with 231.1 and 50.96 g of average live and body weight respectively. Numbers of these white body snails were small with percentage of 22%, and average live and body weight of 128.5 and 30.2 g, respectively. This result suggests that snail A. marginata under breeding in this natural medium showed good performance of growth comparable to those from the original natural medium. Moreover, the study of nutritive value parameters revealed that body of both varieties of A. marginata had the similar ash content of 9.8% with important calcium contents of 17.38±0.37 and 20.34±2.94% for black and white body varieties, respectively. The shell ash content of both snail varieties showed identical value of 95% with calcium contents of 17.38±0.37 and 20.34±2.94% for black and white body varieties, respectively. Their body protein content was estimated at approximately 62%.

Statistical and Spatial Evaluation of the Belier Region (Ivory Coast) Hydromorphic Soils Fertility for Paddy Field Cultivation. In the region of Belier localized in the centre of Ivory Caost, the agricultural production can be increased and diversified thanks to hydromorphic soils, but these soils are deserted most of the times by farmers. So, it appears very important to evaluate the fertility of these soils, in particular their fertility for paddy field cultivation. The method we adopted is based on parametric method of soils evaluation using GIS. The results show that 40%, 50% and 10% of the whole studied soils which covers 474,06 km2, are, respectively, not favourable, little favourable and very favourable for paddy field cultivation.

Enzymatic synthesis of neoglucoconjugates by purified α-glucosidase from cockroach Periplaneta americana (Linnaeus). Cockroach Periplaneta americana (Linnaeus) contains in his digestive tract an acid (pH 5,0) and mesophile (50°C) α-glucosidase. This enzyme, purified to homogeneity, hydrolyses highly maltose, sucrose and p-nitrophenyl-α-Dglucopyranoside. The ability of α-glucosidase from cockroach purified to homogeneity to catalyse transglucosylation reactions was tested using maltose and saccharose as glucosyl donors and 2-phenylethanol and phenol as acceptors. The experimental conditions were optimized in relation to the time course of the reaction, pH and concentrations of glucosyl donors and acceptors. The yields in transglucosylation reactions at 37 °C were very high and could attain 67% and 48% with 2-phenylethanol and phenol respectively as glucosyl acceptors. This α-glucosidase hydrolyzed the products formed. It seems that the products formed were the phenylethyl-α-D-glucoside and phenyl-α-D-glucoside. These results suggest that α- glucosidase from cockroach is an exoglucosidase which catalyse the splitting of the α-glucosyl residue from the non reducing terminal of the substrate to liberate α-glucose. This comportment indicates that this enzyme operated by a mechanism involving the retention of the anomeric configuration. On the basis of this work, α-glucosidase from P. americana appears to be a valuable tool for the preparation of α-neoglucoconjugates.

Nutritional Values of Three Plantain Hybrids CRBP 39, FHIA 17 and FHIA 21 by Comparing them with that of Orishele Variety. This study is to estimate the nutritional values of plantain hybrids CRBP 39, FHIA 17 and FHIA 21 by comparing them with that of Orishele variety as control. For this purpose, Wistar rats weighing in average 82 ± 1.23 g were fed with these plantain diets. The results show good nutritional values of these plantain hybrids. Their daily ingestions by rats vary from 8.41 ± 0.08 to 9.41 ± 0.07 g/d; and an increase in rat weight ranging from 8.38 ± 0.16 to 8.74 ± 0.20 g/d is observed. Plantains used are digested well; their digestibilities vary from 98.43 ± 0.01% to 99.02 ± 0.01% for starch and from 95.38 ± 0.01 to 95.84 ± 0.13% for dry matter. Hybrids starch digestibilities are significantly different from that of the Orishele variety (P≤ 0.05). Rats fed with these plantain hybrids diets have a glycemia ranging from 0.7 to 1.2 g/l with no significant difference.

Nitrogen Balance of Dried Maggot's Meal in Growing Rats. Au Gabon, la chute secondaire des feuilles constitue le principal problème de la culture d'hévéas. Dans la plantation où le GT1 est le clone le plus abondant (55%), on enregistre chaque année pendant la grande saison des pluies (marsavril) un développement de l'anthracnose à Colletotrichum gloeosporioides. On observe des attaques très sévères sur les hévéas qui se traduisent par la chute des jeunes feuilles atteintes. De ce fait, la densité foliaire dépasse difficilement 50% tout au long de l'année. Des études antérieures réalisées sur le clone GT1 ont montré qu'on pouvait lutter contre cette anthracnose en réalisant une défoliation artificielle provoquant la chute des feuilles et une refoliation avant que les conditions favorables au développement du champignon ne s'établissent. Il faut toutefois deux à trois traitements successifs sur ce clone pour obtenir des résultats satisfaisants et cela s'avère assez coûteux. Par contre, notre étude montre qu'un seul traitement suffit pour lutter contre la chute secondaire des feuilles et améliorer substantiellement la production du caoutchouc, à condition qu'il y ait une association de clones. La présence, sur les mêmes parcelles, de clones sensibles et moins sensibles dans des proportions à peu près équivalentes empêche la propagation du champignon après la défoliation artificielle. Dans les conditions écologiques du Gabon, il est donc recommandé de ne pas planter un clone à plus de 25%.

Purifi cation and caracterization of two acid phosphatases from cocoyam tuber (Xanthosoma sp.) and its role on postharvesting preservation. Two forms of acid phosphatases (EC 3.1.3.2) were purifi ed from enzymatic crude extract of cocoyam tuber Xanthosoma sp., «atoumbou oronô» variety. This variety of cocoyam is cultivated and eaten in south and south-East areas of Côte dʼIvoire. These two phosphatases (PI and PII) exhibiting maximum activities at pH respectively 5.4 and 5.8 were purifi ed to homogeneous by polyacrylamide gel electrophoresis in native conditions. In SDS-PAGE, PI and PII showed each other one band with molecular weights of 25,000 and 22,000 respectively. In gel fi ltration, the molecular weights of the two acid phosphatases PI and PII were estimated to 30,000 and 25,000 respectively. These two acid phosphatases were inhibited by Hg2+ and Mo7+ ions and chemicals as DTNB (Dithionitrobenzoic acid), pCMB (4-Chloromercuribenzoic acid) and EDTA (Ethylenediaminetetraacetic acid). However they were activated by Mg2+ and Ca2+. The KM values were 0.72 and 0.30 mM respectively for PI and PII with pNPP (4-Nitrophenyl phosphate). These two acid phosphatases are also able to hydrolyze at different proportions other natural phosphorylated substrates like glucose-1-phosphate, galactose-1-phosphate, glucose-6- phosphate and NADP. PI hydrolyzed ATP but not PII. The two acid phosphatases hydrolyzed pyrophosphate. However, PI [KM = 0.61 mM and catalytic effi ciency (Vmax/KM = 213)] made it better than PII, it suggests that pyrophosphate should be one of the physiological substrates of this acid phosphatase involved in the metabolic process during the post-harvesting preservation of cocoyam tuber.

Research and Comparative Study of Proteasic Activities of Neutral Castes of Termite Macrotermes subhyalinus (Termitidae, Macrotermitinae) and its Symbiotic Fungus Termitomyces sp. Crude extracts from neutral castes of the termite Macrotermes subhyalinus, its symbiotic fungus Termitomyces sp. and its comb are not able to hydrolyze acyl-pNA tested on acid medium. However, these substrates on alkaline medium are hydrolysed, indicating that these enzymatic sources possess proteolytic activities. Hydrolyzed acyl-pNA are Gly-pNA, LeupNA, Met-pNA, Phe-pNA, Pro-pNA, Lys-pNA, ArgpNA and Asp-pNA. The highest proteolytic activities were obtained with Leu-pNA and BA-pNA with a Macrotermes subhyalinus termite worker. It is therefore more active than the soldier. Proteolytic activities were higher in small soldiers than in large ones. The proteolytic activities of the fungus are higher than those of the fungus comb, its growth backbone. Mutal competition studies among the best hydrolysed substrates by symbiotic fungus and worker have shown that trypsic activities (Arg-pNA, Lys-pNA and BA-pNA) are derived from the same enzyme. This enzymatic reaction has also been observed with Leu-pNA, MetpNA and Ala-pNA.