Taxonomic study of entomopathogenic nematodes (Nematoda : Steinernematidae, Heterorhabditidae) from Benin

A study on the biodiversity of entomopathogenic nematodes was conducted during 2010 and 2011 in South Benin. Soil samples from eight sites production of annual and perennial crops were analysed. We obtained 13.21 % of positive soil samples out of 280. We here report on the identification of six of these isolates. Molecular, morphometrical and morphological observations classified the isolates within the genus Heterorhabditis ; one isolate was conspecific with H. indica and two other isolates with H. sonorensis. More information is needed for effective identification of the remaining three isolates. Phylogenic analysis based on sequences of ITS regions of rDNA grouped our isolates with H. sonorensis and H. taysearae with bootstrap support values of 94 and 99 % in Maximum Parsimony and Neighbour Joining trees, respectively. Morphological characters of the infective juveniles and males did not correspond to those of H. taysearae, but were close to H. sonorensis. In contrast, the female of the H. sonorensis populations did show some minor differences with the originally described one. No progeny was obtained from the crossbreeding of Beninese isolates and H. taysearae. Crossing with an isolate of H. sonorensis would have been more conclusive, but no isolates were available even for specimen’s morphological comparison.Keywords : Survey, identification, Molecular, cross-hybridization, Heterorhabditis.Etude taxonomique desnematodes entomopathogenes (Nematoda : Steinernematidae, Heterorhabditidae) du BeninUne étude diagnostique réalisée sur les nématodes entomopathogènes (NEP) en 2010 et 2011 dans le Sud- Bénin sur huit sites de production de cultures annuelles et pérennes a conduit à 13,21 % d’échantillons de sols positifs sur 280. Le présent travail a porté sur l’identification de six des isolats de NEP extraits. Les études moléculaires, morphologiques, morphométriques et d’hybridation effectuées utilisant les stades développementaux des nématodes ont révélé un isolat d’H. indica, deux d’H. sonorensis. Pour les autres isolats, des informations complémentaires sont nécessaires pour une identification complète. Le séquençage et l’analyse phylogénétique de la région interspécifique de l’ADN ribosomal ont groupé nos isolats avec H. sonorensis et H. Taysearae dans les arbres de parcimonie maximale et de Neighbour Joining avec les supports respectifs 94 et 99 %. Les caractères morphologiques des juvéniles infectieux et des mâles ne correspondent pas à ceux de la première description d’H. taysearae, mais sont proches d’H. sonorensis. Cependant, certaines femelles avec bouchon copulatoire ne correspondent pas à H. sonorensis. Nos isolats n’ont pas été féconds avec H. taysearae. Un croisement avec H. sonorensis population type serait plus concluant, mais il n’y avait aucun isolat disponible dans la base de gènes.Mots-clés : Etude, identification, moléculaire, hybridation-croisée, Heterorhabditis

Structures, Deformation Mechanisms and Tectonic Phases, Recorded in Paleoproterozoic Granitoids of West African Craton, Southern Part: Example of Kan’s Complex (Central of Côte d’Ivoire)

The granito-gneissic complex of Kan is located in the central part of the Paleoproterozoic domain of Côte d’Ivoire. It consists essentially of migmatitic and mylonitic gneisses with basic intrusions and xenoliths. This Proterozoic domain belongs to the Man Leo shield, southern part of West African craton (WAC). The present study, essentially based on a structural analysis at outcrop scale, aims to identify deformation mechanisms and tectonic phasesrecorded in the granito-gneissic complex of Kan. Deformation mechanisms include: (1) flattening, (2) constriction, (3) simple shear (4), rotation (5), brittle shear, and (6) extension. The Kan complex deformation occurred during four major tectonic phases named D1, D2, D3 and D4. D1 corresponds to WNW-ESE compression. It led to the formation of NS to NNE-SSW foliation, of stretching lineation, and of folds with sub-horizontal axes. It is accompanied by N170° and N10° sinistral shear zones, which constitute globally a NS major transcurrent shear zone in the central part of Côte d’Ivoire. D1 is also marked by N90° dextral shear zones. Tectonic phase D2 is associated with EW compression. It is marked by N50° dextral and N110° sinistral transcurents shear zones. D3 corresponds to NNE-SSW compressive phase and is responsible of N110° crenulation cleavage formation. (D4) constitutes a brittle deformation phase. It correspondsto posteburnean deformation in the Proterozoic crust of Côte d'Ivoire. Generally, these deformation phases are similar to D2 and D3 reported in the Man-Leo shield and that are part of regional collisional phase referred to as Eburnean orogeny in the WAC

Valuation of rice postharvest losses in Sub-Saharan Africa and its mitigation strategies

Data on rice harvest and postharvest loss in Sub-Sahara Africa (SSA) is scanty making it difficult for stakeholders to appreciate the loss and set priority areas for loss reduction along the value chain. To address this problem, a protocol was developed and validated for postharvest loss (PHL) quantification in SSA. Quantitative losses at each segment were determined by field measurements. Interactive effect of origin of rice (domestic versus imported) and type of processing (white versus parboiled milled) on rice price in 33 markets in Africa was used to estimate qualitative loss for both white and parboiled milled rice. Total PHL for rice in SSA in 2018 is estimated at about US$ 10.24 billion, representing 47.63% of the expected total production. The highest loss recorded was quantitative loss before and during harvesting, followed by qualitative loss along the entire value chain, quantitative loss during milling, parboiling, threshing in that order, with the lowest being quantitative loss during drying. Priority areas to be targeted for PHL reduction in SSA and some loss mitigation tools and technologies piloted or suitable for SSA are proposed

Animal traction in Ghana

Non-PRGSSP; IFPRI5DSG

Can smallholder farmers grow? Perspectives from the rise of indigenous small-scale farmers in Ghana

This paper examines the process of growth and the drivers of transition using a quantitative survey of Ghanaian medium- and large-scale farmers. The paper departs from the competing visions on whether to promote small-scale or large-scale farms in Sub-Saharan Africa (SSA) primarily by arguing that an important transition of onetime small-scale farmers is taking place in Ghanaian agriculture and potentially in other SSA countries. This transition is largely unresearched, although it is a critical feature of agricultural transformation with implications for agricultural development strategies in the SSA sub-region. Acknowledgement : We would like to thank the United States Agency for International Development for providing financial support for this study through the IFPRI s Ghana Strategy Support Program. We thank Shashidhara Kolavalli and Xinshen Diao for their insightful comments on this research. This research also benefited from comments by Xiaobo Zhang, Guush Berhane Tesfay and numerous other IFPRI staff during the IFPRI s Retreat for IFPRI Staff Everywhere (RISE). We are solely responsible for any errors and omissions

Animal traction- potential and constraints

Non-PRGSSPDSG