Breeding system, gene dispersal and small-scale spatial genetic structure of a threatened food tree species, Pentadesma butyracea (Clusiaceae) in Benin

Pentadesma butyracea Sabine, a rain forest food tree species, plays a vital role in the socio-economic livelihood of some West African rural communities due to its various products. However, its scattered populations are threatened in Benin. Defining appropriate conservation strategies requires a good knowledge of mating patterns and their consequences for population genetics. The outcrossing rate, levels of correlated paternity and fine-scale spatial genetic structure of adults and maternal sibships were estimated for one small population and three large populations in Benin using microsatellite markers. Similar outcrossing rates (88 - 95%) were found in all populations, showing that P. butyracea is mainly an outbreeding species. We found no evidence of inbreeding depression from a decay of inbreeding with age. The spatial genetic structure within the large populations (Sp statisticSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Reproductive biology of Pentadesma butyracea (Clusiaceae), source of a valuable non timber forest product in Benin

Background and aims – The main reproductive traits of the native African food tree species, Pentadesma butyracea Sabine (Clusiaceae), which is threatened in Benin and Togo, were examined in Benin to gather basic data necessary to develop conservation strategies in these countries. Methodology – Data were collected on phenological pattern, floral morphology, pollinator assemblage, seed production and germination conditions on 77 adult individuals from three natural populations occurring in the Sudanian phytogeographical zone. Key results – In Benin, Pentadesma butyracea flowers once a year during the dry season from September to December. Flowering entry displayed less variation among populations than among individuals within populations. However, a high synchrony of different floral stages between trees due to a long flowering period (c. 2 months per tree), might still facilitate pollen exchange. Pollen-ovule ratio was 577 ± 213 suggesting facultative xenogamy. The apical position of inflore scences, the yellowish to white greenish flowers and the high quantity of pollen and nectar per flower (1042 ± 117 μL) represent floral attractants that predispose the species to animal-pollination. The main pollinators were two sunbirds ( Cyanomitra verticalis, Cinnyris coccinigastrus ) and three Hymenoptera ( Apis mellifera, Meliponula togoensis, Hypotrigona sp.). Mean fruit set reached 49%, and absolute fruit production increased with tree size. Seeds were desiccation-sensitive (i.e. recalcitrant) with a maximum duration of hydrated storage of three months. Germination of seeds was most successful and rapid at 30°C (50% after nine days). Conclusions – Our results indicate that the natural reproduction of P. butyracea is not limited by its ecology so that we hypothesize anthropogenic activities to be the reason for the threatened status of P. butyracea in Benin and Togo. However, due to its recalcitrant seeds, the conservation of its genetic resources is not feasible through ex situ conservation of seed banks but in situ strategies and/or ex situ conservation in orchards should be successful

Reproductive biology of Pentadesma butyracea (Clusiaceae), source of a valuable non timber forest product in Benin

Background and aims – The main reproductive traits of the native African food tree species, Pentadesma butyracea Sabine (Clusiaceae), which is threatened in Benin and Togo, were examined in Benin to gather basic data necessary to develop conservation strategies in these countries. Methodology – Data were collected on phenological pattern, floral morphology, pollinator assemblage, seed production and germination conditions on 77 adult individuals from three natural populations occurring in the Sudanian phytogeographical zone. Key results – In Benin, Pentadesma butyracea flowers once a year during the dry season from September to December. Flowering entry displayed less variation among populations than among individuals within populations. However, a high synchrony of different floral stages between trees due to a long flowering period (c. 2 months per tree), might still facilitate pollen exchange. Pollen-ovule ratio was 577 ± 213 suggesting facultative xenogamy. The apical position of inflore scences, the yellowish to white greenish flowers and the high quantity of pollen and nectar per flower (1042 ± 117 μL) represent floral attractants that predispose the species to animal-pollination. The main pollinators were two sunbirds ( Cyanomitra verticalis, Cinnyris coccinigastrus ) and three Hymenoptera ( Apis mellifera, Meliponula togoensis, Hypotrigona sp.). Mean fruit set reached 49%, and absolute fruit production increased with tree size. Seeds were desiccation-sensitive (i.e. recalcitrant) with a maximum duration of hydrated storage of three months. Germination of seeds was most successful and rapid at 30°C (50% after nine days). Conclusions – Our results indicate that the natural reproduction of P. butyracea is not limited by its ecology so that we hypothesize anthropogenic activities to be the reason for the threatened status of P. butyracea in Benin and Togo. However, due to its recalcitrant seeds, the conservation of its genetic resources is not feasible through ex situ conservation of seed banks but in situ strategies and/or ex situ conservation in orchards should be successful

Farmer’s Knowledge and Perception of Diversified Farming Systems in Sub-Humid and Semi-Arid Areas in Benin

Building on farmer’s agroecological knowledge to design environmental-friendly agricultural systems is crucial given the environmental impact of industrial agriculture. We investigated the drivers of farmers’ knowledge of agrobiodiversity management and analyzed how farmers’ knowledge and their current farming contexts may guide future farming systems in sub-humid (Bassila) and semi-arid (Boukoumbé) areas of Benin. We conducted structured interviews with 180 farmers and used generalized linear models and correlation analyses to understand the spatio-temporal dynamics of farmers’ knowledge and perception. Land tenure, ecological conditions and sociolinguistic membership were the main drivers of farmers’ knowledge of agroforestry systems, practices, species diversity and current farming systems. Sociolinguistic membership also significantly predicted farmers’ knowledge of livestock management. Farmers in the semi-arid area were more involved in integrated crop-tree-livestock systems than those in the sub-humid area. However, all farmers indicated a willingness to adopt this integrated farming system regardless of socioeconomic and ecological factors. Farmer’s knowledge of agrobiodiversity (crops, agroforestry species and livestock diversity) management was correlated with the involvement in integrated crop-livestock-tree and agroforestry systems. These findings provide insights into how farmers’ knowledge can serve as basis in optimizing agricultural and livelihoods systems. Investigating the ecological, economic and social performance of the most desired integration/diversification options using a system approach involving a co-innovation process can further our mechanistic understanding of farmers decision making process

Indigenous cowpea production and protection practices in Benin

A survey involving more than 129 farmers was carried out in 1998 and 1999 in Ouémé, Benin, to investigate the importance of pests and diseases as constraints to cowpea (Vigna unguiculata (L.) Walp.) production. Results indicated that in the Ouémé valley Sclerotium rolfsii Sacc. and Aphis craccivora Koch are specific concerns. Weeds such as Justicia anselliana (Nees) T. Anders, Ipomoea aquatica Forsskal and Commelina erecta L. were also reported as being troublesome. On the Ouémé plateau Imperata cylindrica L. Beauv. was reported to be a major weed. Callosobruchus maculatus Fab. and Bruchidius atrolineatus Fab. may cause up to 100% loss within a few months in storage. Birds and rodents were also reported. In certain areas on the plateau, farmers have developed pest control methods based on indigenous knowledge. In the valley the population density of Eichhorniacrassipes (Mart) Solms. during flooding is used by farmers to predict aphid infestation. A number of plant species used to protect cowpea were reported. In Gbékandji village, natural enemies such as Rhabdepyris sp., Evania sp., and Chelonus sp., were observed. They were rare in the valley, where farmers rely on chemical control. Farmers reported alternative hosts of cowpea pests from the families Fabaceae (eight species), Mimosaceae (two species), Ceasalpiniaceae (five species), Capparidaceae (two species) and Pontederiaceae (one species). Based on the hierarchy of constraints, sustainable integrated pest management technologies are being developed with farmers using a participatory approach. RÉSUMÉ Bien que des options de lutte existent, les ravageurs et les maladies demeurent la principale contrainte à la production du niébé (Vigna unguiculata (L.) Walp.). Les problèmes phytosanitaires du niébé ont fait l'objet d'enquêtes menées en 1998 et 1999 auprès de plus de 129 paysans dans la vallée et sur le plateau du département de l'Ouémé au Sud Bénin. Les résultats montrent que dans la vallée, Sclerotium rolfsii Sacc. et Aphis craccivora Kock sont des préoccupations spécifiques. Les mauvaises herbes: Justicia anselliana (Nees) T. Anders, Ipomoea aquatica Forsskal et Commelina erecta L. y sont préoccupantes. Imperata cylindrica L. Beauv. est la plus nuisible sur le plateau. Callosobruchus maculatus Fab. et Bruchidius atrolineatus Fab. peuvent occasionner 100% de perte en quelques mois de stockage. Les oiseaux et les rongeurs ont été signalés. Dans certaines zones du plateau, des paysans ont développé des méthodes de protection basées sur des connaissances endogènes. Selon les paysans de la vallée, la densité de peuplement d'Eichhornia crassipes (Mart) Solms. pendant l'inondation permet de prédire l'infestation de pucerons. Des plantes à effet insecticide ont été signalées. Dans le village de Gbékandji, des ennemis naturels: Rhabdepyris sp., Evania sp., et Chelonus sp., etc. ont été observés. Ils étaient rares dans la vallée où l'utilisation de produits chimiques est prononcée. Les paysans ont rapporté des hôtes alternatifs des déprédateurs de niébé de la famille des Fabaceae (08 espèces), Mimosaceae (02 espèces), Ceasalpiniaceae (05 espèces), Capparidaceae (02 espèces) et Pontederiaceae (01 espèce). Se basant sur la hiérarchisation des contraintes, des méthodes participatives de mise au point de technologies durables de lutte intégrée sont en cours d'élaboration

Genetic Improvement of Iron Toxicity Tolerance in Rice-Progress, Challenges and Prospects in West Africa

In sub-Saharan Africa, the demand for higher rice production continues to grow rapidly. Although there is a huge potential for increasing rice production through expansion of the rice cultivation area in wetlands, iron (Fe) toxicity tends to occur and consequently results in low rice yield. Development and deployment of varieties tolerant to Fe toxicity is one of the practical options to overcome this constraint. Several tolerant varieties have been developed through conventional breeding but progress in breeding has been generally slow mainly due to large genotype × environment interaction and field heterogeneity, which make rice selection ineffective. In addition, there are no valid managed-stress screening protocols which are highly efficient and that can predict rice performance in the diverse target environments of West Africa. Many O. glaberrima accessions have superior tolerance, but only a few of them have been utilized in breeding programs. The known quantitative trait loci (QTLs) related to Fe toxicity, have not been used for marker-assisted selection (MAS), as they gave small effects with a large confidence interval. Accelerating rice breeding efficiency for tolerance to Fe toxicity requires establishment of reliable screening protocols, use of O. glaberrima accessions as donors, identification of large-effect QTLs and MAS using such QTLs. This paper reviews the past and current efforts in West Africa to develop new varieties with superior tolerance to Fe toxicity

Soil-based screening for iron toxicity tolerance in rice using pots

The objective of this study was to assess the reliability of pot-based screening method for iron (Fe) toxicity tolerance in rice using soils from hot spots. Five lowland rice varieties with known reaction to Fe toxicity were grown in pots in a screen house for three seasons. Fe-toxic soils from two hot spot fields – Edozighi, Nigeria and Niaouli, Benin were used and soil from Africa Rice Center (AfricaRice) experimental farm, Cotonou, Benin was included as control. Leaf bronzing score (LBS) was determined at different stages, and grain yield was determined at maturity. Heritability was estimated using data across the three seasons. High heritability was recorded for LBS and grain yield. Grain yield reduction in stress treatment relative to control varied from 15 to 56% depending on the variety and soil. Bao Thai, Suakoko 8, and WITA 4 had better performance under Fe toxicity in terms of LBS, yield and relative yield reduction, whereas Bouake 189 and IR64 had poorer performance. Grain yield and LBS were significantly correlated but negatively at 60 days after sowing (DAS). Overall, the results found in this experiment were consistent with previous field studies. Therefore, pot screening using soils from hot spots can be used by rice breeding programs to reliably assess Fe toxicity tolerance ex situ

Enhancing germination and seedling growth in

Introduction. Many fruit trees with a hard seed coat exhibit seed dormancy, posing problems for their regeneration. Vitex doniana, an indigenous multipurpose but threatened fruit and vegetable tree that supports the livelihoods of many households in West Africa, is a typical example. Materials and methods. In our research, we evaluated five dormancy-breaking treatments. We tested the effects of sulphuric acid at 95% concentration (T1); 3 d sun-drying + 48 h soaking in tap water (T2); 3 d alternation of 8 h sun-drying + 1 h soaking in tap water (T3); 2 weeks sun-drying with regular watering in the daytime (T4); and physical shock (T5). These treatments were compared with two controls (T0 and Tc), with seeds from two different sources. The germination percentage, mean germination time, time to first germination and time to threshold germination (20%) were compared; the seedling height, diameter and biomass produced were monitored for 15 weeks. We used generalised linear models and correlation tests to compare the effects of the various treatments on germination and seedling growth. Results and discussion. T3 significantly enhanced seed germination in V. doniana (72% after 12 months). T4 best promoted homogeneity in germination (p < 0.01), followed by T3. The best seedling growth was obtained with T4 and T3. Alternation of sun-drying followed by soaking of seeds, a technique with almost no cost, improved seed germination in V. doniana and, in 33 d, just over 1 month, 20% germination can be achieved. Vitex doniana is a fast-growing species (at the nursery stage), in contrast to the common opinion. Conclusion. Our method should be further investigated to assess the adequate soaking and drying length so as to speed up germination and reach homogenous cohorts

Farmers’ Knowledge and Management Practices of Fall Armyworm, Spodoptera frugiperda (J.E. Smith) in Benin, West Africa

Spodoptera frugiperda has caused significant losses of farmer income in sub-Saharan countries since 2016. This study assessed farmers&rsquo; knowledge of S. frugiperda, their perceptions and management practices in Benin. Data were collected through a national survey of 1237 maize farmers. Ninety-one point eight percent of farmers recognized S. frugiperda damage, 78.9% of them were able to identify its larvae, and 93.9% of the maize fields were infested. According to farmers, the perceived yield losses amounted to 797.2 kg/ha of maize, representing 49% of the average maize yield commonly obtained by farmers. Chi-square tests revealed that the severity of the pest attacks was significantly associated with cropping practices and types of grown maize varieties. About 16% of farmers identified francolin (Francolinus bicalcaratus), village weaver (Ploceus cucullatus), and common wasp (Vespula vulgaris) as natural enemies and 5% of them identified yellow nutsedge, chan, shea tree, neem, tamarind, and soybean as repellent plants of S. frugiperda. Most farmers (91.4%) used synthetic pesticides and 1.9% of them used botanical pesticides, which they found more effective than synthetic pesticides. Significant relationships exist between farmers&rsquo; management practices, their knowledge, organization membership, and contact with research and extension services. More research is required to further understand the effectiveness of botanical pesticides made by farmers against S. frugiperda and to refine them for scaling-up