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

Drivers of conservation and utilization of pineapple genetic resources in Benin

Valuation of farmer knowledge has been seen as a route to promote sustainable use of plant genetic resources. In pineapple production systems in Benin, inadequate knowledge of cultivation practices can lead to a number of inconveniences including abandon of some varieties and cultivars. To understand how farmers' knowledge and cultivation practices impact the sustainable utilization of pineapple genetic resources, we surveyed 177 pineapple farmers in southern Benin. We assessed farmers' knowledge and analyzed the relationship between their knowledge and factors such as age, education, and locality of provenance. Pineapple production system was dominated by men (96% respondents). According to farmers, Smooth cayenne is international market-oriented while Sugarloaf mainly targets domestic and regional markets. All farmers recognized that Smooth cayenne provided more income (USD 5,750/ha) than sugarloaf (USD 3,950/ha) in the production systems of southern Benin. The high value of median scores in comparison with the range of possible score showed that most farmers agreed and shared relatively similar knowledge. Correlation matrix and multiple linear regressions showed a significant relationship between farmers'practices and their knowledge of the plant; their knowledge of pineapple varieties is based on fruits traits. Also, farmers' knowledge was associated with locality of provenance. Constraints and options for genetic resources conservation and utilization in the pineapple production systems in Southern Benin were discussed based on current knowledg

Sustainable use and conservation of Vitex doniana Sweet: unlocking the propagation ability using stem cuttings

One of the major constraints for domesticating widely used wild tree resources by local communities is the lack of adequate propagation techniques. In the case of Vitex doniana, seed propagation has usually been reported difficult and vegetative regeneration is rarely explored. To understand how stem cutting size or hormone application affect the regeneration and early growth ability in that species we used two categories of cutting diameter (1cmVitex doniana to reduce the pressure on wild tree population in Benin

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

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, researchersand 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 on24 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 fourprimers. 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 ninegroups 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 RAPDproved 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

Modelling socioeconomic determinants for cultivation and in-situ conservation of Vitex doniana Sweet (black plum), a wild-harvested economic plant in Benin

Background: Cultivation is the most appropriate management option when both demand and harvesting of wild plant species increase beyond natural production levels. In the current study we made the assumption that, besides the intrinsic biological and ecological characteristics of the species, the decision to cultivate and/or to conserve an overharvested wild plant species is triggered by the socioeconomic factors such as land tenure and size, origin of respondents, gender, and users’ knowledge of the plant phenology. Methods: We carried out semi-structured interviews with 178 informants involved in V. doniana exploitation. The data collected were related to socio-demographic characteristics of informants’ household situation, knowledge of the biology and propagation of the species, willingness to cultivate the species, in-situ maintenance of populations, and costs associated with management of the species. According to data types we used Student’s t, Spearman correlation, Kruskal-Wallis, Fisher’s exact and χ2 tests to test the effects of land tenure, origin of respondents, gender and users’ knowledge of plant phenology on the decision making process. Conditional inference tree models and generalized additive models were also used to identify variables which were significantly determinant in the decision to cultivate and/or to conserve the species in-situ. Results: We found that men were more willing to cultivate the species than women and this is conditioned by land area available. The willingness to conserve the species in-situ depends mainly on the total land area available, the number of trees within the landscape, accessibility of the trees, land tenure, gender, location, seedling cost, and trade-off cost for conservation. People who offered more than one US dollar to acquire a seedling of V. doniana, landowners, and those who own a total land area in excess of 6.5 ha were most willing to conserve the species in-situ. Conclusions: From our findings we conclude that future management and conservation initiatives for V. doniana should first target specific user groups for sustainable exploitation of the species. Also, the Cultivation Opportunity Ratio is an important indicator for quick determination of the likelihood of farmers to engage into cultivation and conservation of the species

Selection of sites for the in situ conservation of four traditional leafy vegetables consumed in Benin

Acmella uliginosa, Ceratotheca sesamoides, Justicia tenella and Sesamum radiatum are four traditional leafy vegetables which are widely consumed in Benin. In order to document their origin, folk nomenclature, geographical distribution and ecology and to select adequate zones for in situ conservation of their genetic resources, 118 villages were randomly selected and surveyed throughout the country using a participatory research approach. All the species apart from Ceratotheca sesamoides were reported by farmers as introduced in Benin at different periods. The folk nomenclature comprising 93 different names is based on nine key criteria of variable frequencies according to the species. The geographical distribution maps revealed that the species under study are unequally distributed. Indeed, A. uliginosa is found exclusively in the northwest, J. tenella in the northeast and partially in the centre while S. radiatum and Ceratotheca sesamoides were found almost everywhere in Benin. Results from multivariate analysis combined with geographical distribution maps of the species and the soil and climate maps of Benin, leaded to the selection of the Northwest and of the Northeast regions as the appropriate conservation zones for the four species. Molecular analysis was recommended as it can help in describing genetic diversity and consequently in identifying additional sites for the widely spread species Sesamum radiatum and Ceratotheca sesamoides. Keywords: Folk nomenclature, biodiversity, geographical distribution, site selection, in situ conservation, Benin