IN VITRO MICROPROPAGATION OF NAUCLEA DIDERRICHII (DE WILD &T. DURAND) MERRILL: EFFECT OF NODES POSITION ON PLANTLETS GROWTH AND ROOTING

In tissue culture, the reactivity of explants in culture depends on their position on mother –plant or their physiological development level. This study aims to determine the regenerative potentialities of nodes according to their position for suitable in vitro micropropagation of N. diderrichii’s seedlings. Thus the effect of uninodal explants position of Nauclea diderrichii on seedling growth and rooting was studied in vitro. Three types of nodes (apical, middle and basal node) excised from two months old seedlings were tested using Woody Plant Medium (WPM) containing 30 g/L of sucrose and solidified with agar-agar at 8 g/L. The mean number of roots and shoots per plant was scored as well as the shoots and roots length was measured after six weeks of culture. Apical nodes produced seedlings with highest number of roots (6.80 ± 2.44 roots / plant) followed by basal (5.70 ± 2.68 roots / plant) and middle nodes (4.50 ± 2.12 roots / plant). But middle and basal nodes produced the best number of shoots (1.90 ±0.31 shoots / plantlet) than that obtained with apical nodes (1.30 ±0.57 shoots / plantlet). Seedlings obtained from apical nodes expressed efficient growth (4.70 ± 1.70 cm) compared to the middle (2.18 ± 0.97 cm) and basal nodes (2.33 ± 1.08 cm). So, for a rapid in vitro production of N. diderrichii’s seedlings, apical nodes of in vitro plants are more suitable

IN VITRO MICROPROPAGATION OF NAUCLEA DIDERRICHII (DE WILD &T. DURAND) MERRILL: EFFECT OF NODES POSITION ON PLANTLETS GROWTH AND ROOTING

In tissue culture, the reactivity of explants in culture depends on their position on mother –plant or their physiological development level. This study aims to determine the regenerative potentialities of nodes according to their position for suitable in vitro micropropagation of N. diderrichii’s seedlings. Thus the effect of uninodal explants position of Nauclea diderrichii on seedling growth and rooting was studied in vitro. Three types of nodes (apical, middle and basal node) excised from two months old seedlings were tested using Woody Plant Medium (WPM) containing 30 g/L of sucrose and solidified with agar-agar at 8 g/L. The mean number of roots and shoots per plant was scored as well as the shoots and roots length was measured after six weeks of culture. Apical nodes produced seedlings with highest number of roots (6.80 ± 2.44 roots / plant) followed by basal (5.70 ± 2.68 roots / plant) and middle nodes (4.50 ± 2.12 roots / plant). But middle and basal nodes produced the best number of shoots (1.90 ±0.31 shoots / plantlet) than that obtained with apical nodes (1.30 ±0.57 shoots / plantlet). Seedlings obtained from apical nodes expressed efficient growth (4.70 ± 1.70 cm) compared to the middle (2.18 ± 0.97 cm) and basal nodes (2.33 ± 1.08 cm). So, for a rapid in vitro production of N. diderrichii’s seedlings, apical nodes of in vitro plants are more suitable

Comparison of in vitro morphogenetic capacities of different clones of three local cultivars of sweet potato (Ipomoea batatas) from Togo

Sweet potato (Ipomoea batatas) is an hexaploide plant with complex incompatibility that reduces chances of self-fertilization. In vitro culture of sweet potato by means of biotechnological approaches is an advantage for its study and variety improvement. Three sweet potato cultivars from Togo: Damadoami, Tombolo, Nagohé were grown on Murashige and Skoog (MS) medium with or without indole-3-butyric acid (IBA), and the morphogenetic properties of the plantlets obtained were compared. Uninodal stem explants were used. The reactivity of explants grown on MS differed according to the cultivar and the clone. Addition of IBA induced embryogenesis and root neoformations. The growth depended on the genotype, the clone, and the cultivar. The cultivar Damadoami was the most reactive on MS medium. Plantlets were acclimated easily and can be transferred to the fieldKeywords: Tuberous root, in vitro, morphogenesis, neoformations, indole-3-butyric acid (IBA), Togo.African Journal of Biotechnology Vol. 12(29), pp. 4648-465

CONTRIBUTION À L’ÉVALUATION ET À LA CARTOGRAPHIE DE LA SENSIBILITÉ À L’ÉROSION HYDRIQUE DES SOLS DU SOUS BASSIN VERSANT DE L’OUED DE SAIDA (OUEST DE L’ALGÉRIE)

The sub-watershed of WadiSaidawich is a part of Macta watershed is characterized by a semiarid climate. Erratic rains, usually in stormy character, combined with anthropozoogenic pressure (deforestation, urbanization, overgrazing) cause a severe erosion. According to the National Agency of water resources, sediment yield (sediment from erosion) is estimated at 29667 t / year, which contribute to the siltation of the dam of Ouizert. This study was conducted using a Geographic Information System (GIS), allowed to characterize different areas of the sub-watershed, producing a synthetic map of the distribution of degrees of susceptibility to erosion. Indeed, Three classes of multifactorial vulnerability to water erosion were distinguished, areas with low vulnerability 40.18%; areas with medium vulnerability 24.93% and 34.88% highly vulnerable areas. Thus, classes with medium and high multifactorialvulnerability represent 60% of the area. This first mapping study is a tool to help decision makers to better manage water resources and soil and taking into account the expectations and needs of the rural populatio

Modalites et mecanismes de l'accumulation des acides amines dans les cotyledons des jeunes graines de Phaseolus vulgaris L

SIGLECNRS T 56599 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Structure of sweet potato (Ipomoea batatas) diversity in West Africa covaries with a climatic gradient.

Sub-Saharan agriculture has been identified as vulnerable to ongoing climate change. Adaptation of agriculture has been suggested as a way to maintain productivity. Better knowledge of intra-specific diversity of varieties is prerequisites for the successful management of such adaptation. Among crops, root and tubers play important roles in food security and economic growth for the most vulnerable populations in Africa. Here, we focus on the sweet potato. The Sweet potato (Ipomoea batatas) was domesticated in Central and South America and was later introduced into Africa and is now cultivated throughout tropical Africa. We evaluated its diversity in West Africa by sampling a region extending from the coastal area of Togo to the northern Sahelian region of Senegal that represents a range of climatic conditions. Using 12 microsatellite markers, we evaluated 132 varieties along this gradient. Phenotypic data from field trials conducted in three seasons was also obtained. Genetic diversity in West Africa was found to be 18% lower than in America. Genetic diversity in West Africa is structured into five groups, with some groups found in very specific climatic areas, e.g. under a tropical humid climate, or under a Sahelian climate. We also observed genetic groups that occur in a wider range of climates. The genetic groups were also associated with morphological differentiation, mainly the shape of the leaves and the color of the stem or root. This particular structure of diversity along a climatic gradient with association to phenotypic variability can be used for conservation strategies. If such structure is proved to be associated with specific climatic adaptation, it will also allow developing strategies to adapt agriculture to ongoing climate variation in West Africa

Dendrogram of NJ cluster analysis of 132 sweet potato accessions.

<p>A represents Tropical-Sahelian accessions group 1; B Tropical accessions, C Tropical arid accessions, D Sahelian accessions, and E Tropical-Sahelian accessions group 2. The number indicates the number of accessions. The bootstrap value is given on the branch of the tree.</p

Polymorphic Index Content (PIC) of SSR markers.

<p>The values indicate the PIC of the loci used to analyze our 132 African accessions. Each locus value corresponds to the mean PIC of all the alleles of the corresponding markers. The last bar represents the mean PIC of the 12 markers.</p

Mean number of alleles in the different regions.

<p>America has the highest number of alleles, approximately 11, followed by Oceania with 9 and Africa with 7.</p

Distribution of the genetic group per village.

<p>Distribution of the genetic group per village.</p