Inventaire des variétés, des méthodes locales de stockage et de protection contre les ravageurs de la patate douce (Ipomea batatas L.) dans la bande Ouest du Niger

La patate douce (Ipomoea batatas Lam.) est une culture de subsistance par excellence en Afrique. Comme aliment de soudure, elle joue un rôle majeur dans plusieurs ménages tant urbains que ruraux et sa consommation par habitant est d’environ 84 kg/an. A cet effet, la valorisation de cette culture représente une des meilleures alternatives pour assurer la sécurité alimentaire d’une population en constante croissance et également face à la baisse de la production des cultures vivrières comme le mil, sorgho ou le blé. Pour atteindre cet objectif, une meilleure connaissance de la diversité génétique et la maîtrise des problèmes phytosanitaires s’avère plus que primordiales. Pour cela, des enquêtes ont été menées auprès des producteurs des principales zones de culture en vue d’inventorier les variétés couramment utilisées et les connaissances locales en matière de stockage et de maîtrise des problèmes phytosanitaires de cette plante. Les résultats obtenus ont permis de montrer qu’une diversité de variétés de patate douce est cultivée au Niger. Cependant, le nombre de variétés locales utilisées dépend de la zone d’étude. C’est ainsi que dans la zone d’Ayorou, huit (8) variétés de patate douce ont été recensées contre douze (12) à Balleyara et seize (16) dans la zone de Bengou. Pour lutter contre les ennemis de la culture, les producteurs pratiquent la méthode chimique avec une utilisation abusive de pesticides chimiques qui représentent un danger pour l’environnement. Plusieurs méthodes locales de stockage sont aussi utilisées pour la conservation des tubercules de patate douce (Stockage à l’ombre des arbres, la conservation sur pied, conservation dans de grenier) mais avec des résultats non satisfaisants car les pertes liées au stockage des tubercules restent très élevées.© 2015 International Formulae Group. All rights reserved.Mots clés: patate douce, diversité génétique, connaissances locales, méthodes de lutte, méthodes de stockage, Niger

Revitalizing cultivation and strengthening the seed systems of fonio and Bambara groundnut in Mali through a community biodiversity management approach

Fonio (Digitaria exilis(Kippist)Stapf) and Bambara groundnut (Vigna subterranea(L.)Verdc.) are native crops grown at a small scale in Mali that have potential to support agricultural productivity under climate change. A community biodiversity management approach was explored in this study as a means to reinforce the cultivation of these crops by increasing farmers’ access to intraspecific diversity and developing capacities of community institutions for their management. The research involved six communities in Ségou and Sikasso regions. Multiple varieties of fonio (10–12) and Bambaragroundnut (8–12) were established indiversity fields in each site over 2 years where farmers engaged in experiential learning over the crop cycle. Significant adoption of fonio and Bambara groundnut was detected in several study sites.The precise drivers of adoption cannot be definitively determined but likely include increased seed access and awareness gained through the diversity field fora, seed fairs and community seed banks. No significant yield advantage was detected for any of the varieties in the diversity fields, which showed variable performance by site and year. The number of varieties registered and managed by community seed banks in each site increased from 1–5 varieties of each crop to 11–12 varieties following the interventions. The number of Bambara groundnut varieties cultivated in farmer as light decline in fonio diversity in some communities.The results of this study can inform efforts to strengthen seed systems and cultivation of neglected and underutilized species in Africa

Prospection, Enquête et Collectes des Accessions de Poivron (Capsicum annuum L.) Cultivés dans la Région de Diffa, Niger

Au Niger, particulièrement dans la région de Diffa, le poivron est la spéculation la plus cultivée et la plus commercialisée, représentant ainsi le poumon économique de la région. Pour accroitre la production et prévenir toute érosion génétique, des connaissances sur la diversité génétique et les pratiques paysannes de la gestion du poivron sont nécessaires. C’est ainsi qu’une prospection suivie de collecte de graines a été effectuées dans toute la région de Diffa. La méthode d’obtention des données et de collecte des accessions à consister en des entretiens directs avec les paysans et les commerçants du poivron aléatoirement choisis dans les villages ou sites d’exploitations.  Le géo référencement de tous les sites/villages visités a été effectué et une carte est établie. Dix-neuf (19) sites (ou villages) ont été prospectés à travers la région et cinquante un (51) accessions collectées. L’étude révèle que la culture du poivron est plus pratiquée par la classe d’âge moins avancée (18-45 ans) avec une fréquence qui varie de 50% (Diffa) à 77% (Nguigmi). Cette culture est pratiquée majoritairement par les hommes dans toutes les zones prospectées. Les résultats montrent également que les « kanuri » sont majoritairement producteurs de cette spéculation avec une fréquence qui varie de 84% (Nguigmi) à 100% (Bosso et Diffa). La culture est en régression dans certaines localités (Département de Diffa, de Bosso et de Maine Soroa) compte tenu des certaines contraintes biotiques (ravageurs) et abiotiques (inondation, insécurité). A la fin, du matériel pour les programmes d’amélioration du poivron est disponible au Niger.   In Niger, particularly in the Diffa region, bell pepper is the most cultivated and marketed  crop, thus representing the economic lung of the region. To increase production and prevent genetic erosion, knowledge of genetic diversity and farmers’ practices  is needed. Thus, a survey  followed by seed collection was  conducted throughout the Diffa region. The method of obtaining data and collecting accessions consisted of direct interviews with farmers and bell pepper traders randomly selected in the villages or farmers sites. Geo-referencing of all the sites/villages visited has been carried out and a map  was established. Nineteen (19) sites (or villages) were surveyed across the region and fifty-one (51) accessions collected. The study revealed that bell pepper cultivation is more common among  the younger age group (18-45 years) with a frequency that varies from 50% (Diffa) to 77% (Nguigmi). This crop is grown mainly by men in all the zones surveyed . The results also showed that the "kanuri" are the main producers of this crop with a frequency that varies from 84% (Nguigmi) to 100% (Bosso and Diffa). Production is declining in some localities (Departments of Diffa, Bosso and Maine Soroa) due to certain biotic (pests) and abiotic (flooding, insecurity) constraints.  Finally, materials for bell pepper improvement programs are available in Niger

Prospection, Enquête et Collectes des Accessions de Poivron (Capsicum Annuum L.) Cultivés dans la Région de Diffa, Niger

Le poivron est une plante polyvalente utilisé soit comme épice, soit comme légume-fruit dans la plupart des mets. Sa poudre communément appelé paprika est un condiment largement consommé dans le monde. Au Niger, particulièrement dans la région de Diffa, le poivron est la spéculation la plus cultivée et la plus commercialisée, représentant ainsi le poumon économique de la région. Une prospection suivie d’une enquête et d’une collecte des accessions de poivron a été effectuée dans cinq (5) départements de production de la région de Diffa. Dix-neuf (19) sites/villages ont été prospectés à travers la région. Tous les sites/villages visités ont été géo référencées et une carte a été établie. Au total cinquante un (51) accessions ont été collectées. Il ressort de l’entretien que la culture du poivron est plus pratiquée par la classe d’âge moins avancée avec une fréquence qui varie de 77% (Nguigmi) à 50% (Diffa). Cette culture est pratiquée majoritairement par les hommes dans toutes les zones prospectées. Les résultats montrent également que les kanuri sont majoritairement producteurs de cette spéculation avec une fréquence qui varie de 100% (Bosso et Diffa) à 84% (Nguigmi). La culture est en régression dans certaines localité compte tenu des certaines contraintes biotiques (ravageurs) et abiotiques (inondation, insécurité). Apres les récoltes les fruits sont commercialisés dans les marchés locaux ou régionaux, majoritairement dans le département de Diffa (87%) et en moindre importance dans le département de Bosso (32%). Le prix d’un sac de poivron sec de 17 kg varie de 11 000 à 44 000 FCFA selon les périodes et la disponibilité en quantité et en qualité des fruits.   The pepper is a versatile plant used either as a spice or as a fruit vegetable in most dishes. Its powder commonly called paprika is a widely consumed condiment in the world. In Niger, particularly in the Diffa region, the pepper is the most cultivated and most marketed speculation, thus representing the economic lung of the region. A survey followed by a survey and a collection of pepper accessions was carried out in five (5) production departments of the Diffa region. Nineteen (19) sites/villages were surveyed across the region. All the sites/villages visited have been geo-referenced and a map has been drawn up. A total of fifty one (51) accessions were collected. It appears from the interview that pepper cultivation is more practiced by the younger age group with a frequency that varies from 77% (N’guigmi) to 50% (Diffa). This culture is practiced mainly by men in all surveyed areas. The results also show that the kanuri are mainly producers of this speculation with a frequency that varies from 100% (Bosso and Diffa) to 84% (N’guigmi). Cultivation is declining in some localities due to certain biotic (pests) and abiotic (flooding, insecurity) constraints. After the harvest, the fruits are marketed in local or regional markets, mainly in the department of Diffa (87%) and to a lesser extent in the department of Bosso (32%). The price of a 17 kg bag of dry peppers varies from 11,000 to 44,000 FCFA depending on the period and the availability in quantity and quality of the fruits

Prospection, Enquête et Collectes des Accessions de Poivron (Capsicum Annuum L.) Cultivés dans la Région de Diffa, Niger

Le poivron est une plante polyvalente utilisé soit comme épice, soit comme légume-fruit dans la plupart des mets. Sa poudre communément appelé paprika est un condiment largement consommé dans le monde. Au Niger, particulièrement dans la région de Diffa, le poivron est la spéculation la plus cultivée et la plus commercialisée, représentant ainsi le poumon économique de la région. Une prospection suivie d’une enquête et d’une collecte des accessions de poivron a été effectuée dans cinq (5) départements de production de la région de Diffa. Dix-neuf (19) sites/villages ont été prospectés à travers la région. Tous les sites/villages visités ont été géo référencées et une carte a été établie. Au total cinquante un (51) accessions ont été collectées. Il ressort de l’entretien que la culture du poivron est plus pratiquée par la classe d’âge moins avancée avec une fréquence qui varie de 77% (Nguigmi) à 50% (Diffa). Cette culture est pratiquée majoritairement par les hommes dans toutes les zones prospectées. Les résultats montrent également que les kanuri sont majoritairement producteurs de cette spéculation avec une fréquence qui varie de 100% (Bosso et Diffa) à 84% (Nguigmi). La culture est en régression dans certaines localité compte tenu des certaines contraintes biotiques (ravageurs) et abiotiques (inondation, insécurité). Apres les récoltes les fruits sont commercialisés dans les marchés locaux ou régionaux, majoritairement dans le département de Diffa (87%) et en moindre importance dans le département de Bosso (32%). Le prix d’un sac de poivron sec de 17 kg varie de 11 000 à 44 000 FCFA selon les périodes et la disponibilité en quantité et en qualité des fruits.   The pepper is a versatile plant used either as a spice or as a fruit vegetable in most dishes. Its powder commonly called paprika is a widely consumed condiment in the world. In Niger, particularly in the Diffa region, the pepper is the most cultivated and most marketed speculation, thus representing the economic lung of the region. A survey followed by a survey and a collection of pepper accessions was carried out in five (5) production departments of the Diffa region. Nineteen (19) sites/villages were surveyed across the region. All the sites/villages visited have been geo-referenced and a map has been drawn up. A total of fifty one (51) accessions were collected. It appears from the interview that pepper cultivation is more practiced by the younger age group with a frequency that varies from 77% (N’guigmi) to 50% (Diffa). This culture is practiced mainly by men in all surveyed areas. The results also show that the kanuri are mainly producers of this speculation with a frequency that varies from 100% (Bosso and Diffa) to 84% (N’guigmi). Cultivation is declining in some localities due to certain biotic (pests) and abiotic (flooding, insecurity) constraints. After the harvest, the fruits are marketed in local or regional markets, mainly in the department of Diffa (87%) and to a lesser extent in the department of Bosso (32%). The price of a 17 kg bag of dry peppers varies from 11,000 to 44,000 FCFA depending on the period and the availability in quantity and quality of the fruits

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Genetic analysis in near - isogenic lines of durum wheat: triticum turgidum L. var. durum

The effects of specific plant characteristics on grain yield and others agronomic traits of durum wheat are measurable only by using isogenic lines, which, however, were not usually available. The objective of this thesis was to elucidate the effects of the genes for long glume (P), hairy glume (Hg), non-glaucousness (W/), black glume (Bg), purple culm (Pc) and semidwarfhess (Rht-Alb) on heading date, grain yield and different plant characteristics in near-isogenic lines of durum wheat cv. LD222 (Triticum turgidum L. var. durum). Seven near-isogenic lines (NIL(s)) of durum wheat and the recurrent parent LD222 were grown m three different environmental conditions. A randomized block design was applied. There were four replicates and in each plot the plants were sown in a 30x30cm and its were lined up. The data obtained suggest no yield advantage for all the six genes introduced in the LD222 genetic background. The P gene for long glume (818B) was associated with an increase in heading date, rachis length and the number of non-fertile spikelets per spike. It decreased significantly the number of fertile spikelets per spike, kernels per spike, spikes per m², over all grain yield, harvest index and test weight and we concluded that the P gene has a deterious effects on yield and yield components. However the gene Hg for hairy glume showed a stability in all the characteristics studied and in all environments. The differential responses of the two source of black glume (Bg) indicated that the method employed herein determines the effect of short chromosomal regions rather than those of single gene. Despite, the reduction of kernel weight per spike the genes for non-glaucousness (W/) and purple culm (Pc) did not affect the yield. As expected, the semidwarfhess gene (Rht-Alb) significantly reduced plant height and culm length. It increased the number of days to heading, however significantly decreased the grain yield and harvest index due to the reduction of the 100-kemel weight and tillers per m².Χρησιμοποιήθηκαν επτά σχεδόν ισογονιδιακές σειρές της ποικιλίας LD222 με σκοπό τη μελέτη της επίδρασης των γονιδίων που κωδικοποιούν την παρουσία του μακριού λεπύρου (Ρ), την απουσία γλαυκοπράσινου χρώματος (W/), του τριχωτού λεπύρου (Hg), του μαύρου λεπύρου (Bg), του ιώδους στελέχους (Pc) και του ημινανισμού (Rht-Alb), στην πρωιμότητα, στην απόδοση και στα χαρακτηριστικά που σχετίζονται με αυτή και στο εκατολιτρικό βάρος στο σκληρό σιτάρι. Το πείραμα έγινε σε τρία διαφορετικά περιβάλλοντα. Χρησιμοποιήθηκε το σχέδιο των τυχαιοποιημένων πλήρων ομάδων με τέσσερις επαναλήψεις. Κάθε πειραματικό τεμάχιο περιλάμβανε 24 φυτά που είχαν σπαρθεί σε αποστάσεις 30x30 εκ. Το γονίδιο Ρ προκάλεσε οψίμηση. Μείωσε σημαντικά την απόδοση σε καρπό, τον δείκτη συγκομιδής και το εκατολιτρικό βάρος. Τα γονίδια για το τριχωτό λέπυρο (Hg) και το μαύρο λέπυρο (Bg) δεν παρουσίασαν οποιαδήποτε σημαντική επίδραση στην απόδοση και στο εκατολιτρικό βάρος. Παρά τη σημαντική μείωση του βάρους των κόκκων ανά στάχυ που προκάλεσαν τα γονίδια για το μη γλαυκοπράσινο (W/) και ιώδες στέλεχος (Pc), δεν είχαν επιπτώσεις στην απόδοση και στο εκατολιτρικό βάρος. Το γονίδιο ημινανισμού (Rht-Alb) προκάλεσε οψιμότητα στο ξεστάχυασμα και μείωσε σημαντικά το ύψος του φυτού και την απόδοση σε σπόρο

Variabilité Morphologique Et Agronomique Des Morphotypes De Voandzou (Vigna Subterranea (L.) Cultivés Dans La Zone Sahélienne Du Niger

In Niger, Bambara groundnut is mainly grown by women in pure culture on small areas and without improved technics. However, improving the production of this crop can help to ensure food security. Knowledge of Bambara groundnut's diversity will allow its use in breeding programs. This study concerns the agro-morphological characterization in the Sahelian agroclimatic zone of fourteen (14) morphotypes of Bambara groundnut identified in the Nigerien accessions collection. The data used are collected through an agronomic test using a complete random block design, with four repetitions. Twelve (12) characters including 01 phenological, 08 morphological and 03 related to the yield components at harvest were evaluated. Descriptive statistical analysis showed that the coefficients of variation ranged from 10.3% (early flowering) to 72% (seeds weight per plant). Significantly high values (CV> 20%) were observed for 07 characters out of 12 analyzed. Agromorphological characterization revealed significant differences between the 09 parameters of the morphotypes. It was found that the Ne-10 and Ne-14 morphotypes are more efficient in grain yield, with 10.8 and 9.6 g / plant, respectively. Late-flowering morphotype (Ne-01) had the lowest yield. Strong correlations were observed in the morphological parameters, with r = 0.82 between the petiole length and the width of the terminal leaflet. A correlation of the same order was obtained between the wingspan of the plant and the width of the terminal leaflet, with r = 0.76. For yield parameters, strong correlations were observed between seed weight per plant and pod weight per plant (r = 0.96), and between same seed weight and number of pods per plant (r = 0.87). The dendrogram classified the morphotypes into 4 groups, with the Ne-14 and Ne-01 morphotypes each forming two isolated groups, the Ne-04 and Ne-08 morphotypes forming the third group and the 10 others together constituting the fourth group

Age-based targeting of biannual azithromycin distribution for child survival in Niger: an adaptive cluster-randomized trial protocol (AVENIR)

Background: biannual distribution of azithromycin to children 1–59 months old reduced mortality by 14% in a cluster-randomized trial. The World Health Organization has proposed targeting this intervention to the subgroup of children 1–11 months old to reduce selection for antimicrobial resistance. Here, we describe a trial designed to determine the impact of age-based targeting of biannual azithromycin on mortality and antimicrobial resistance. Methods: AVENIR is a cluster-randomized, placebo-controlled, double-masked, response-adaptive large simple trial in Niger. During the 2.5-year study period, 3350 communities are targeted for enrollment. In the first year, communities in the Dosso region will be randomized 1:1:1 to 1) azithromycin 1–11: biannual azithromycin to children 1–11 months old with placebo to children 12–59 months old, 2) azithromycin 1–59: biannual azithromycin to children 1–59 months old, or 3) placebo: biannual placebo to children 1–59 months old. Regions enrolled after the first year will be randomized with an updated allocation based on the probability of mortality in children 1–59 months in each arm during the preceding study period. A biannual door-to-door census will be conducted to enumerate the population, distribute azithromycin and placebo, and monitor vital status. Primary mortality outcomes are defined as all-cause mortality rate (deaths per 1000 person-years) after 2.5 years from the first enrollment in 1) children 1–59 months old comparing the azithromycin 1–59 and placebo arms, 2) children 1–11 months old comparing the azithromycin 1–11 and placebo arm, and 3) children 12–59 months in the azithromycin 1–11 and azithromycin 1–59 arms. In the Dosso region, 50 communities from each arm will be followed to monitor antimicrobial resistance. Primary resistance outcomes will be assessed after 2 years of distributions and include 1) prevalence of genetic determinants of macrolide resistance in nasopharyngeal samples from children 1–59 months old, and 2) load of genetic determinants of macrolide resistance in rectal samples from children 1–59 months old. Discussion: as high-mortality settings consider this intervention, the results of this trial will provide evidence to support programmatic and policy decision-making on age-based strategies for azithromycin distribution to promote child survival. Trial registration: This trial was registered on January 13, 2020 (clinicaltrials.gov: NCT04224987).</p