Genetic variability of cultivated cowpea in Benin assessed by random amplified polymorphic DNA

Characterization of genetic diversity among cultivated cowpea [Vigna unguiculata (L.) Walp.] varieties is important to optimize the use of available genetic resources by farmers, local communities, researchers and breeders. Random amplified polymorphic DNA (RAPD) markers were used to evaluate the genetic diversity in 70 cowpea accessions collected throughout Benin. Nine random primers were screened on 24 accessions to assess their ability to reveal polymorphisms in cowpea and four of them were selected for use in characterizing the total sample. A total of 32 amplified bands were generated by the four primers. The number of loci detected varied from 5 to 11. RAPD profiles were analysed and amplified polymorphic DNA fragments were used to construct a dendrogram, clustering the accessions into nine groups at a similarity index of 71% based on the Unweighted Pair-Group Method using Arithmetic Averages. The genetic diversity among the cowpea cultivars investigated was large and the RAPD proved to be a useful technique to characterise it. Based on the molecular variance, the fixation index suggests a large differentiation of cowpea cultivars in Benin

Socio-economic, agronomic and molecular analysis of yam and cowpea diversity in the Guinea-Sudan transition zone of Benin

Keywords: Cowpea (Vigna unguiculata(L.) Walp.),yam ( Dioscorea spp. ), agro-biodiversity, farmer perception, market and consumer preferences, socio-cultural preferences, human and social capitals, genotype by environment interaction, socio-technical knowledge, domestication, inter-(trans)disciplinarity / Beta-gamma science.Management and use of yam and cowpea genetic resources analysed in this thesis are important to realize agricultural development inBenin, both on the short and long run. In this thesis the diversity of local varieties of yam and cowpea, often ignored by classical research, is analysed. Different meth­odological approaches, including technography, diagnostic study at village level, and joint farmer-researcher managed experimentation, have been combined with socio-cultural, market and consumer studies. Molecular tools have been used to assess the level of genetic diversity in these two crops.Socio-cultural determinants, market and consumers' preferences, and the morphological and agronomic characteristics of different varieties of these two crops are all relevant for social acceptability and adaptability, and for the adoption of new varieties by local subsistence farmers. Different yam and cowpea varieties are used for rituals each year. The yield performance varied from one variety to another, and within one variety, from one year to another (or one place to another) depending on variability in agro-climatic conditions. While any successful variety of yam or cowpea should be adapted to stressful agro-climatic or poor soil conditions, it should be also adapted to the often specific needs of the farmer and to his/her socio-cultural environment. Moreover, varieties need to satisfy consumer preferences and market demands. Often, one single variety of yam or cowpea cannot meet all these criteria. Given these multiple purposes and multiple objectives, adequate management of diversity of varieties is essential to farmers, as a strategy to cope with food security and income generation all year round.Prices of different varieties of yam and cowpea on the market reflect the food technological or taste characteristics perceived or recognized by consumers in these varieties. The market provides important information on diversity of varieties and on their characteristics.Based on the morphogenetic and physiological characteristics recognized by farmers as limitations, or as natural constraints in the proper use of seed tubers of different yam varieties, this thesis undertook a participatory technology development programme with farmers to improve the knowledge of both the researcher and the farmers of seed tuber propagation through induced sprouting, and through use of different parts of the tuber as planting materials. The thesis also pays attention to farmers' own experimentation in developing new yam varieties by domesticating wild yams, and shows that this activity - probably of ancient provenance inBenin- remains effective for farmers excluded by poverty from market participation. The improvement of the performance of these localvarieties remains a major future task for researchers and policy-makers inBenin.Two major conclusions can be drawn from this thesis. The first is that both social and natural sciences are necessary contributors to the understanding of diversity in yam and cowpea varieties as managed and maintained by farmers. This diversity is expressed at the molecular level and at farm level, but is also highly relevant on the market and in the socio-cultural life of the farmers. The second conclusion relates to findings concerning the possibility of engaging farmers and researchers in joint study of yam and cowpea diversity, with beneficial practical consequences. Joint experimentation focused on varietal characterization, and the joint participatory technology development, indicated that more effective research results can be obtained when farmers' perceptions and depth of experience is fully incorporated in research design. In this regard, technography and diagnosis remain continuously reviewed, allowing the incorporation of new ideas or innovations and new stakeholders in the experimentation process. The results assessment with and by farmers remains an essential aspect of judging work in farmer conditions to improve local livelihoods. In particular, the thesis emphasizes that - through domestication of yam - the poor show that they can contribute actively to development of scientific perspectives. These aspects of the Convergence of Sciences as focused upon yam and cowpea varietal management embrace both an inter-disciplinary and trans-disciplinary research perspective. Cooperation and co-knowledge generation with farmers needs follow-up, and a scaling-up to reach other farmers. Specifically, it needs to be incorporated in the curricula of national research training systems

Potentialités de l’acarien prédateur Amblyseius swirskii (Athias-Henriot) (Acari: Phytoséiidae) dans la lutte biologique contre la mouche blanche Bemisia tabaci (Genn.), vecteur de la mosaïque du manioc en Afrique

La mosaïque africaine du manioc est une maladie redoutable qui ravage les champs de manioc en Afrique. Elle est causée par un virus dont le vecteur principal est la mouche blanche Bemisia tabaci. Un des moyens de lutte contre cette maladie passe par la lutte contre le vecteur B. tabaci, réputé très résistant aux insecticides chimiques. L’acarien prédateur phytoséiide Amblyseius swirskii a été identifié en Europe comme un potentiel prédateur de B. tabaci. Dans une série d’études au laboratoire nous avons déterminé la capacité de deux populations (israélienne et béninoise) de A. swirskii à contrôler les populations de B. tabaci, réduisantainsi l’incidence de la mosaïque sur les plants de manioc. Pour chacune des deux populations du prédateur, les taux de prédation, d’oviposition et de survie des femelles adultes nourries aux larves de premier stade de B.tabaci, en présence ou en absence de pollen de maïs, étaient très faibles par rapport à ceux obtenus dans des études précédentes avec du pollen de la massette, Typha australis ou du maïs. Aussi, les paramètresbiologiques démographiques montrent que sur les larves de B. tabaci le niveau de population de A. swirskii a décru très rapidement pour s’annuler, attestant que B. tabaci n’est pas une proie idéale pour le prédateur. Autotal, ces résultats indiquent que A. swirskii ne serait pas un bon agent de lutte biologique contre B. tabaci sur les plants de manioc en Afrique.Mots clés : Manihot esculenta, aleurode, Aleyrodidae, paramètres démographiques, supplément nutritif

Genetic variability in yam cultivars from the Guinea- Sudan zone of Benin assessed by random amplified polymorphic DNA

Yam (Dioscorea spp.) is an important food and cash crop in the Guinea-Sudan zone of Benin. The genetic diversity of about 70 cultivars of Dioscorea cayenensis/Dioscorea rotundata (Guinea yam) andabout 20 cultivars of Dioscorea alata (water yam) was analysed using random amplified polymorphic DNA (RAPD). The amplified bands revealed high polymorphism. These polymorphic DNA fragmentswere used to construct dendrograms, clustering all accessions into 18 groups: 12 for D. cayenensis/D. rotundata and six for D. alata. The analysis of molecular variance revealed highly significant variationamong species, among groups within species, and among cultivars within groups. The study showed that the genetic diversity changed along a spatial gradient. In general, there was a tendency that mostof the varieties from the north-east and north-west of the zone investigated appeared to be distinctive from the ones of the centre. However, few varieties were distributed randomly and did not reflect anyspecific relation to their zone of collection. The current study suggests that the Guinea-Sudan zone of Benin has a large gene pool of yam varieties. Yam farmers may have played a significant role in theenrichment and the maintenance of the genetic diversity of yam

Efficacite technique des producteurs de mais participant au warrantage dans le nord-est du Benin

Face au bradage massif des productions agroalimentaires en période de récolte, le warrantage a été promu pour faciliter l’accès des producteurs au crédit agricole, aux marchés des facteurs de production et de produits agricoles afin d’améliorer leur efficacité technique et leurs revenus agricoles. La présente étude vise à mesurer le niveau d’efficacité technique des producteurs de maïs participants et non participants au warrantage dans une région du Bénin et à déterminer les facteurs qui influencent cette efficacité. L'approche d'estimation en une seule étape de la frontière stochastique de production et du modèle qui détermine les facteurs d'inefficacité technique a été appliquée à un échantillon aléatoire stratifié de 314 producteurs de maïs dont 157 producteurs participants au warrantage. Les résultats ont montré que les producteurs n’opèrent pas tous sur la frontière de production. Le niveau moyen d’efficacité technique a été de 74 % avec 78 % pour les bénéficiaires et 70 % pour les non bénéficiaires. Le niveau actuel moyen de leur production annuelle qui est de 16 014 kg pourrait être encore amélioré de 33 % avec les mêmes ressources productives. L’accès au warrantage, le sexe, l’utilisation de la semence améliorée de maïs, l’appartenance à un groupement de producteurs hors warrantage et la possession d’un moyen d’information sont les facteurs qui influencent positivement l’efficacité technique des producteurs. Ainsi, il est important que l’évaluation de l’impact du warrantage soit réalisée afin d’améliorer sa promotion. English title: TECHNICAL EFFICIENCY OF MAIZE PRODUCERS PARTICIPATING IN WARRANTAGE IN THE NORTHEASTERN OF BENIN Abstract Faced with the massive sell-off of agri-food production during the harvest period, warrantage was promoted to facilitate producers’ access to agricultural credit, production factors and agricultural products markets in order to improve their technical efficiency and farm income. This study aims to measure the level of technical efficiency of maize producers participating and not participating in warrantage in a region of Benin and to determine the factors that influence this efficiency. A one stage stochastic frontier production which incorporates a model for the technical ineffiency effects was applied to a stratified random sample of 314 maize producers, including 157 producers participating in warrantage. The results showed that the producers do not operate on the production frontier. The average level of technical efficiency is 74% with 78% for beneficiaries and 70% for non-beneficiaries. The current average level of their annual production, which is 16,014 kg, could be further improved by 33% with the same productive resources. Access to warrantage, gender, use of improved maize seed, membership in a non-warrantage producers’ group and possession of a means of information are the factors that positively influence the technical efficiency of producers. Thus, it is important that the impact of warrantage be evaluated in order to improve its promotion. Maize; technical efficiency; warrantage; stochastic production frontier; Beni

Adaptations of cowpea varieties (Vigna unguiculata (L.) Walp.) to the environmental variability in Benin

The study was realized in the context of farmer management of genotype by environment interaction. The objective was to determine the agronomic and morphological characteristics commonly used by farmers to assess farmer named cowpea varieties through a joint farmer researcher characterization. The trial design was a completely randomized block with 70 varieties as treatments, replicated four times. Data were analyzed using Shannon-Weaver diversity Index and the Analysis of Variance. These varieties varied in growth habit, in colours of leaves, stems, flowers, pods and seeds, and in seed shape and texture. The Shannon- Weaver diversity index revealed a high global mean of morphological diversity among the varieties (H’=1.23), ranging from 1.02 for pod pigmentation to 1.61 for seed coat colour. Within regions, this index varied from 0.33 to 1.57, depending on considered characteristic. Farmers used the photoperiodic response of the late varieties to distinguish early-maturing from late-maturing varieties. In a 3-year experiment, the variety by environment interactions, as expressed by variety-specific effects of planting date, season, and year on yield and yield components, were highly significant. The late-maturing varieties have shown longer reproductive period and more pods and seeds per plant, and higher yield than the early ones.Keywords: Diversity, Vigna unguiculata, photoperiodism, varieties, genotype by environment interaction, yield, Benin Adaptations des varietes de niebe (Vigna unguiculata (L.) Walp.) a la variabilite environnementale au BeninDans un contexte de gestion d’interaction génotype x environnement, l’objectif était de déterminer les caractéristiques agronomiques et morphologiques couramment utilisées par les paysans pour évaluer les variétés de niébé. Le dispositif a été un bloc aléatoire complet avec 70 variétés comme traitements, répétés quatre fois. Les données ont été analysées avec l’indice de diversité de Shannon-Weaver et l’analyse de variance. Ces variétés diffèrent par la croissance, les couleurs des feuilles, des tiges, des fleurs, des gousses et des graines, la forme et la texture de la graine. L’indice de diversité a révélé une grande diversité morphologique globale moyenne entre les variétés (H’= 1,23), allant de 1,02 pour la pigmentation des gousses à 1,61 pour la couleur du tégument de la graine. Pour une région donnée, cet indice a varié de 0,33 à 1,57, en fonction de la caractéristique considérée. A partir du photopériodisme, les paysans ont pu séparer les variétés stardives des variétés précoces. Sur 3 ans, les interactions génotype x milieu exprimées par des effets spécifiques de date de semis, de saison, et d’année sur le rendement et ses composantes étaient significatives. Les variétés tardives ont une période de fructification plus longue et ont significativement plus de gousses et graines par plante et de plus hauts rendements que les variétés précoces. Mots clés: Diversité, Vigna unguiculata, variétés, photopériodisme, interaction génotype x environnement, rendement, Bénin

Effectiveness of neem seed oil (Azadirachta indica A. Juss: Meliaceae) on Syllepte derogata Fabricius, Lepidoptera: Pyralidae

Objective: Synthetic insecticides have long been used for cotton protection,  resulting in pest resistance, toxicity and environmental pollution. Biopesticides have been suggested as alternatives to synthetic pesticides. Both field and laboratory experiments were conducted to evaluate the effectiveness of neem oil in controlling Syllepte derogata (Fabricius), a cotton phyllophagous pest.Methodology and Results: In the field trials, effect of neem oil was compared to that of conventional insecticides; while in the laboratory direct larval immersion and leaf dip method using EMA SUPER 56DC and neem oil were tested. Decrease in damage by S. derogata for about 63 and 86% was recorded with neem oil and synthetic insecticides. In the laboratory, the mortality of S. derogata after 24 hours exposure to neem oil and Ema Super was significantly higher (2.5 to 100%) than that of the control. The mortality of larvae of S. derogata was positively correlated with the concentration of neem oil and exposure time. Lethal Concentration (LC50) after 24 hours exposure of larvae was respectively 4.03 104 ml/l and 51.13 ml/l forleaf dipping method and larval immersion.Conclusion and application of results: Overall, these results showed the efficacy of neem oil in controlling S. derogata, as a biopesticide. This oil could also  constitute a successful alternative to synthetic pesticides. However, the  effectiveness of neem oil appeared to be weakened by the rapid degradation of the active substances, azadirachtin in particular. Indeed, azadirachtin, the main active ingredient of neem is photo and heat labile. It easily degrades under high solar radiations and high temperatures, hence the need for stabilization.Keywords: Phyllophagous pest, integrated pest management, leaf-dipping method, larval immersion, Lethal Concentration

Enhanced ultrasonically assisted extraction of bitter melon (Momordica charantia) leaf phenolic compounds using choline chloride-acetic acid–based natural deep eutectic solvent: an optimization approach and in vitro digestion

This is the final version. Available on open access from Springer via the DOI in this recordBitter melon (Momordica charantia) is a rich source of phytochemicals including phenolic compounds with diverse health-promoting benefits and potential food industry application due to their antioxidant potential. Bitter melon leaves have been limitedly investigated in comparison to bitter melon fruits. The current work explores the use of green extraction methodology to optimize enhanced extraction of phenolic compounds from bitter melon leaves using ultrasonically assisted extraction and choline chloride-acetic acid (CHAC)–based natural deep eutectic solvent. Extraction using CHAC significantly improved the extraction of total phenolic compounds, total flavonoids, and individual phenolic compounds (including gallic acid, chlorogenic acid, vanillic acid, epicatechin, and quercetin-3-glucoside) in comparison to water, ethanol, and methanol. The effect of molar ratio, water content, temperature, and time on the extraction efficiency of bitter melon leaf phenolic compounds by CHAC was explored and optimized with surface response methodology (central composite design). The optimum condition for the extraction of individual phenolic compounds is a molar ratio of 1:4.35 CHAC with 20.68% water content at 75 °C for 21.23 min. Evaluation of the bioaccessibility of individual phenolic compounds concluded that the most bioaccessible compound was vanillic acid (105.00 ± 2.52%) followed by salicylic acid, chlorogenic acid, syringic acid, gallic acid, epicatechin, and quercetin-3-glucoside.Ondokuz Mayis Universit

Drying date plum (Diospyros lotus L.) fruit: Assessing rehydration properties, antioxidant activity, and phenolic compounds

This is the final version. Available on open access from Wiley via the DOI in this recordDate plum (Diospyrus lotus L.) is an edible fruit from the Ebenaceae family, rich in nutrients, and having tremendous medicinal properties. This paper attempted to show the influence of different parameters of convective drying such as temperature (50, 60, 70, and 80°C) and air velocity (0.5, 1.0, and 1.5 m/s) on the shrinkage and microstructure, rehydration properties, antioxidant activity, and phenolic compounds of date plum. The drying caused significant changes in the color, actual size, and distribution of the fruit cells of date plum. The total phenolic content (TPC), total flavonoid content (TFC), ferric reducing antioxidant power (FRAP), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) of fresh date plum were 0.81 ± 0.00 mg GAE/g, 0.23 ± 0.10 mg ECE/g, 7.15 ± 1.09 mmol ISE/g, and 14.92 ± 0.88 mmol/TE, respectively. The drying at 70°C had the highest values of TPC, TFC, gallic acid, chlorogenic and syringic acids, catechin, quercetin-3-glucoside, resveratrol, and DPPH. The drying air velocities showed no significant effects on the antioxidant contents and the antioxidant activity. Of the models applied to the drying kinetics, the Midilli model was found as the best model to describe the drying kinetics of date plum. In addition, the Weibull model was found as the most successful among the models applied to the rehydration kinetics of date plum. According to the achieved findings, the convective drying temperature of 70°C is the optimum temperature to produce the dehydrated date plum. Practical Application This work has revealed the drying conditions responsible for preserving the phenolic compounds, total flavonoid content, and antioxidant features of D. lotus L. The study found the optimum drying conditions, and Midilli and Weibull models were the most fitted models to describe the drying and rehydration behaviors of D. lotus L. fruits, respectively. The drying provides a reasonable value of the possibility of continuous consumption of the fruits dried afforded on off-seasons. The dried fruits are widely used for multipurpose and have been extensively used in food industries due to their rich nutraceutical and antioxidant compounds