Occurrence of Banana bunchy top virus in banana and plantain (Musa sp.) in Benin

In July 2011, banana and plantain that displayed stunting and leaf symptoms typical of banana bunchy top disease were observed to be widespread in Dangbo Commune, Ouémé Department, Benin. To identify the cause of the disease, a roving survey was conducted in December 2011 in nine locations in Avrankou, Dangbo, Akpro-Missérété and Porto-Novo Communes, in Ouémé. In each location, the incidence of symptom-bearing plants was estimated from counts of 15 mats, and samples were collected for Banana bunchy top virus (BBTV) assessment. Approximately 60% of the 94 banana mats assessed had plants exhibiting typical symptoms of BBTV infection - chlorotic leaf margins, dark green streaks on petioles, narrow leaves that bunched at the top, and severe stunting. Total DNA was extracted from 25 leaf samples collected from plants with symptoms; they were then tested for BBTV by polymerase chain reaction. The sequences showed 100% nucleotide sequence identity with a BBTV isolate from Cameroon (FJ580970) and 99-100% identity with several other BBTV isolates from the GenBank database belonging to the South Pacific group, which consisted of BBTV isolates from Africa, Australia, India and South Pacific. This finding confirmed that the virus isolate associated with the diseased plants in Benin was of the BBTV South Pacific type. This is thought to be the first report of BBTV in Benin. The disease is widespread in all the four communes surveyed

Improving women's purchasing power through land-enhancing technologies: The case of bio-reclamation of degraded lands in Niger

In Niger, about 50% of the land surface is composed of degraded lateritic soils, and rural women farmers have limited access to productive land. Targeting largely marginalized rural women with bio-reclamation of degraded land (BDL) technologies restores their rights to earn a livelihood through agriculture. This study examines the determinants and impacts of land-enhancing technology on women farmers in Niger. Data were collected from 1,205 randomly selected women farmers in the Maradi and Zinder regions. The sample included 69% of participants into BDL program and 31% of non-participants. To account for selection bias from observable and unobservable factors, an endogenous switching regression (ESR) model was used to estimate the impact of BDL technology on women's household income. A simple probit model was used to analyze the determinants of participation. The results show that key determinants of participation in BDL include income level before participation in BDL, household size, age of participants, number of women in the household, number of children under 5 years old, sex of household head, age of household head, and institutional support. Participation in BDL positively influences participants' income (+14%); non-participants may not benefit from participating as they would probably lose 31% of their income, and the impact of participation in BDL varies widely across regions. Before the advent of BDL, the income of non-participants was higher than that of participants by 25%. It can be inferred that BDL is a pro-poor technology that is not beneficial to all women farmers. This study makes a critical contribution to the literature on land-enhancing technologies. It suggests that the impact of land-enhancing technologies, such as BDL, is closely linked to spatial, economic, environmental, temporal, and cultural contexts. Accordingly, land-enhancing technologies should target locations with large percentages of degraded farmlands and the poorest farmers. These results contribute to food security and poverty alleviation policies in rural dryland areas

Viabilité et performance de germination des semences de Acacia auriculiformis A. Cunn. ex Benth. (Fabaceae) issues du sol de la forêt classée de Pahou (Sud Bénin)

La récolte des semences de Acacia auriculiformis devient très difficile lorsque l’arbre prend de l’âge. Cette étude a évalué la viabilité et la performance de germination des semences de cette espèce éventuellement conservées dans le sol. À cet effet, une expérimentation a été faite sur une période de sept semaines pour dénombrer le nombre de plantules en émergence à partir des échantillons composites de sol collectés dans une vieille plantation de Acacia auriculiformis au Sud Bénin. L’échantillonnage est stratifié, aléatoire sur le plan horizontal (provenance), mais systématique sur le plan vertical (profondeur). Les échantillons ont été mis en conditions minimales de germination. La méthode de germination a été utilisée pour évaluer la viabilité et la performance de germination des semences. L’indépendance de ces paramètres vis-à-vis des facteurs considérés a été testée avec Khi-2. Enfin, les tendances observées ont été expliquées par les modèles GLM. La profondeur et la provenance se révèlent avoir des influences significatives sur les paramètres mesurés. Le sol de la plantation peut contenir jusqu’à 267 semences viables de Acacia auriculiformis par m² surtout à l’intérieur de la plantation dans la première couche du sol. Il est possible de faire recours à ces semences du sol pour pallier les difficultés liées à l’approvisionnement en plants au Bénin.The harvest of the seeds of Acacia auriculiformis becomes very difficult when the tree gets older. This study has assessed the viability, and the germination performance of the species’ seeds eventually conserved in the soil. For this purpose, an experiment was carried out over a period of seven weeks to count the number of seedlings emerging from the composite soil samples collected in an old plantation of Acacia auriculiformis in South Benin. Samples were randomly collected over a horizontally stratified scale (provenance), but systematically collected over a vertically stratified scale (depth). The samples have been set to minimum conditions of germination. Germination method was used to assess the viability and the germination performance of seeds. The independence of those parameters with regard to considered factors was tested with Khi-2. Finally, GLM models were used to explain the recorded trends. Depth and provenance seem both to significantly influence assessed parameters. Soil from the plantation can hold up to 267 viable seeds of Acacia auriculiformis per m² especially inside the plantation in the first layer of the ground. It is possible to rely on those soil’s seeds to alleviate the difficulties related to seedling supply in Benin

Functional stacking of three resistance genes against Phytophthora infestans in potato

Functional stacking of broad spectrum resistance (R) genes could potentially be an effective strategy for more durable disease resistance, for example, to potato late blight caused by Phytophthora infestans (Pi). For this reason, three broad spectrum potato R genes (Rpi), Rpi-sto1 (Solanum stoloniferum), Rpi-vnt1.1 (S. venturii) and Rpi-blb3 (S. bulbocastanum) were selected, combined into a single binary vector pBINPLUS and transformed into the susceptible cultivar Desiree. Among the 550 kanamycin resistant regenerants, 28 were further investigated by gene specific PCRs. All regenerants were positive for the nptII gene and 23 of them contained the three Rpi genes, referred to as triple Rpi gene transformants. Detached leaf assay and agro-infiltration of avirulence (Avr) genes showed that the 23 triple Rpi gene transformants were resistant to the selected isolates and showed HR with the three Avr effectors indicating functional stacking of all the three Rpi genes. It is concluded that Avr genes, corresponding to the R genes to be stacked, must be available in order to assay for functionality of each stack component. No indications were found for silencing or any other negative effects affecting the function of the inserted Rpi genes. The resistance spectrum of these 23 triple Rpi gene transformants was, as expected, a sum of the spectra from the three individual Rpi genes. This is the first example of a one-step approach for the simultaneous domestication of three natural R genes against a single disease by genetic transformation

Analysis of Adoption of Improved Groundnut Varieties in the Tropical Legume Project (TL III) States in Nigeria

Agricultural technologies and innovations play a great role in increasing productivity, alleviating and reducing poverty and contributing to economic development and this is made possible through adoption of improved technologies and innovations. This study centered on analysis of adoption of improved groundnut varieties in the Tropical Legume (TL III) States of Nigeria. Purposive and simple random sampling techniques were used to select 1476 groundnut farmers in the project States and from whom primary data were collected using electronic data capturing instrument containing the questionnaire. The data were analyzed using descriptive statistics and Average Treatment Effect (ATE) framework. The results showed that the breeding and promotion of improved groundnut varieties in Nigeria under the Tropical Legume Project and with the synergy of USAID groundnut up-scaling Project in Nigeria resulted in very high level of awareness of improved varieties, more than average level of access to the improved variety seeds, moderate level of utilization of the improved varieties among the groundnut farmers and the adoption rate of improved varieties increased from 8% at based line to 57% at the end of the project. The study recommends extension of the project to facilitate further access to these varieties and for state governments to take ownership of the projects in terms of financial commitments to promotional efforts for mass adoption by farmers

Differential household vulnerability to climatic and non-climatic stressors in semi-arid areas of Mali, West Africa

Semi-Arid Regions (SARs) of West Africa are considered climate change “hotspots” where strong ecological, economic and social impacts converge to make socio-ecological systems particularly vulnerable. While both climatic and non-climatic drivers interact across scales to influence vulnerability, traditionally, this inter-connectedness has received little attention in vulnerability assessments in the region. This study adopted the vulnerability patterns framework, operationalized using the Multidimensional Livelihood Vulnerability approach to include both climatic and nonclimatic stressors to analyze differential household vulnerability in SARs of Mali. Findings showed that while drought was the most mentioned climate-related stressor, households were also exposed to a diversity of environmental and socio-economic stressors, including food scarcity, livestock disease, labour unavailability, crop damage, and erratic rainfall patterns. The typology revealed three vulnerability archetypes differentiated by adaptive capacity and sensitivity. Availability of productive household members, household resource endowments, livelihood diversification and social networks were the main discriminant factors of household adaptive capacity, while challenges relating to food and water security make households more sensitive to stressors. The analysis highlighted the heterogeneity in household vulnerability patterns within and across communities. Failing to account for this heterogeneity in adaptation planning might result in a mismatch between adaptation needs and interventions, and potentially in maladaptation

Accelerated cloning of a potato late blight–resistance gene using RenSeq and SMRT sequencing

Global yields of potato and tomato crops are reduced owing to potato late blight disease, which is caused by Phytophthora infestans. Although most commercial potato varieties are susceptible to blight, wild potato relatives are not and are therefore a potential source of Resistance to P. infestans (Rpi) genes. Resistance breeding has exploited Rpi genes from closely related tuber-bearing potato relatives, but is laborious and slow 1–3. Here we report that the wild, diploid non-tuber-bearing Solanum americanum harbors multiple Rpi genes. We combine R gene sequence capture (RenSeq4) with single-molecule real-time SMRT sequencing (SMRT RenSeq) to clone Rpi-amr3i . This technology should enable de novo assembly of complete nucleotide-binding, leucine-rich repeat receptor (NLR) genes, their regulatory elements and complex multi-NLR loci from uncharacterized germplasm. SMRT RenSEQ can be applied to rapidly clone multiple R genes for engineering pathogen-resistant crops

Surgical Task Shifting in Sub-Saharan Africa

Kathryn Chu and colleagues discuss some of the experiences of surgical task shifting to date, and outline lessons from task shifting in the delivery of HIV/AIDS care