Diversité Floristique Et Variation Altitudinale De La Structure Des Formations A Gnidia Glauca (Fresen) Gilg. Dans Les Forêts Communautaires De KilumIjim (Nord-Ouest Cameroun)

In order to find strategies for sustainable management of resources, a study was carried out on the analysis and management of stands of Gnidia glauca in the Kilum-Ijim region (North-West Cameroon). All individuals were identified and counted in 33 plots of 40mx40m established between 1963 and 2785 m altitude in these Gnidia glauca formations. The height and diameter of each individual were measured. A quadrat of 1m² was established around the mature trees to evaluate the regeneration. ANOVA was used to compare the average density of the species in various plots and the DUNCAN test at the 5% significance level (SPSS software version 17.0) was used to separate these means. It emerges from this study that the Thymelaeaceae (G. glauca) family is mainly represented. The Asteraceae, Rubiaceae, Poaceae and Fabaceae are the most diverse families in these formations. The distribution of individuals of G. glauca in diameter classes shows a decreasing pattern. The low density of G. glauca is observed at low altitudes (166.66 stems / hectare), and the high density is between 2350 and 2450 m (778.18 stems / ha). The average standing densities of G. glauca varies between 64.58 and 459.37 stems per hectare; these values indicate a good regeneration of this species in the site. G. glauca can therefore be rationally exploited in a sustainable way for the well-being of the surrounding human populations

Agro-ecological distribution of the phenotypic diversity of aerial yam (Dioscorea bulbifera L.) in Cameroon using multivariate analysis : prospect for germplasm conservation and improvement

Aerial yam (Dioscorea bulbifera L.) is a crop of great economic importance and an excellent candidate for improving food security in developing countries. Understanding the genetic variability of any crop species is a decisive step for its improvement and requires characterization and evaluation of available germplasm. The objectives of this study were to determine the extent of genetic variability, estimate the association between agromorphological traits and clustering among 57 genotypes of aerial yam from three distinct agro-ecological zones in Cameroon using multivariate analysis. Thirty nine characters (23 qualitative and 16 quantitative) were used for the study. Significant differences in genetic diversity indices were found. Accessions from the bimodal humid forest zone (Na = 2.08, He = 0.27) showed significantly lower diversity compared to both western highland (Na = 2.30, He = 0.34) and humid monomodal forest zones (Na = 2.57, He = 0.32). Means values of most quantitative traits also showed significant differences between agro-ecological zones. Batingla-3 and Bawouwoua-1 had important bulbil yield, reaching 3500 g / plant. Significant associations were found between many traits. The use of the Unweighted Pair Group Method with Arithmetic Mean allowed the distribution of the 57 genotypes into six distinct clusters with the clustering pattern not showing any parallelism with location sites or agro-ecological zones. Mahalanobis D-2 statistics revealed the highest inter-cluster distance between cluster II and VI. Accessions of these clusters are potential parents for future breeding programs. This study showed that aerial yam from Cameroon has an enormous wealth of traits variation, indicating huge potential for its genetic improvement through selection and hybridization

Agro-ecological distribution of the phenotypic diversity of aerial yam (Dioscorea bulbifera L.) in Cameroon using multivariate analysis: prospect for germplasm conservation and improvement

Aerial yam (Dioscorea bulbifera L.) is a crop of great economic importance and an excellent candidate for improving food security in developing countries. Understanding the genetic variability of any crop species is a decisive step for its improvement and requires characterization and evaluation of available germplasm. The objectives of this study were to determine the extent of genetic variability, estimate the association between agromorphological traits and clustering among 57 genotypes of aerial yam from three distinct agro-ecological zones in Cameroon using multivariate analysis. Thirty nine characters (23 qualitative and 16 quantitative) were used for the study. Significant differences in genetic diversity indices were found. Accessions from the bimodal humid forest zone (Na = 2.08, He = 0.27) showed significantly lower diversity compared to both western highland (Na = 2.30, He = 0.34) and humid monomodal forest zones (Na = 2.57, He = 0.32). Means values of most quantitative traits also showed significant differences between agro-ecological zones. Batingla-3 and Bawouwoua-1 had important bulbil yield, reaching 3500 g / plant. Significant associations were found between many traits. The use of the Unweighted Pair Group Method with Arithmetic Mean allowed the distribution of the 57 genotypes into six distinct clusters with the clustering pattern not showing any parallelism with location sites or agro-ecological zones. Mahalanobis D2 statistics revealed the highest inter-cluster distance between cluster II and VI. Accessions of these clusters are potential parents for future breeding programs. This study showed that aerial yam from Cameroon has an enormous wealth of traits variation, indicating huge potential for its genetic improvement through selection and hybridization

The future of food: domestication and commercialization of indigenous food crops in Africa over the third decade (2012–2021)

This paper follows the transition from ethnobotany to a deeper scientific understanding of the food and medicinal properties of African agroforestry tree products as inputs into the start of domestication activities. It progresses on to the integration of these indigenous trees as new crops within diversified farming systems for multiple social, economic and environmental benefits. From its advent in the 1990s, the domestication of indigenous food and non-food tree species has become a global programme with a strong African focus. This review of progress in the third decade is restricted to progress in Africa, where multi-disciplinary research on over 59 species has been reported in 759 research papers in 318 science publications by scientists from over 833 research teams in 70 countries around the world (532 in Africa). The review spans 23 research topics presenting the recent research literature for tree species of high priority across the continent, as well as that in each of the four main ecological regions: the humid zone of West and Central Africa; the Sahel and North Africa; the East African highlands and drylands; and the woody savannas of Southern Africa. The main areas of growth have been the nutritional/medicinal value of non-timber forest products; the evaluation of the state of natural resources and their importance to local people; and the characterization of useful traits. However, the testing of putative cultivars; the implementation of participatory principles; the protection of traditional knowledge and intellectual property rights; and the selection of elite trees and ideotypes remain under-researched. To the probable detriment of the upscaling and impact in tropical agriculture, there has been, at the international level, a move away from decentralized, community-based tree domestication towards a laboratory-based, centralized approach. However, the rapid uptake of research by university departments and national agricultural research centres in Africa indicates a recognition of the importance of the indigenous crops for both the livelihoods of rural communities and the revitalization and enhanced outputs from agriculture in Africa, especially in West Africa. Thus, on a continental scale, there has been an uptake of research with policy relevance for the integration of indigenous trees in agroecosystems and their importance for the attainment of the UN Sustainable Development Goals. To progress this in the fourth decade, there will need to be a dedicated Centre in Africa to test and develop cultivars of indigenous crops. Finally, this review underpins a holistic approach to mitigating climate change, as well as other big global issues such as hunger, poverty and loss of wildlife habitat by reaping the benefits, or ‘profits’, from investment in the five forms of Capital, described as ‘land maxing’. However, policy and decision makers are not yet recognizing the potential for holistic and transformational adoption of these new indigenous food crop opportunities for African agriculture. Is ‘political will’ the missing sixth capital for sustainable development

Trees and their seed networks: The social dynamics of urban fruit trees and implications for genetic diversity

Trees are a traditional component of urban spaces where they provide ecosystem services critical to urban wellbeing. In the Tropics, urban trees’ seed origins have rarely been characterized. Yet, understanding the social dynamics linked to tree planting is critical given their influence on the distribution of associated genetic diversity. This study examines elements of these dynamics (seed exchange networks) in an emblematic indigenous fruit tree species from Central Africa, the African plum tree (Dacryodes edulis, Burseraceae), within the urban context of Yaoundé. We further evaluate the consequences of these social dynamics on the distribution of the genetic diversity of the species in the city. Urban trees were planted predominantly using seeds sourced from outside the city, resulting in a level of genetic diversity as high in Yaoundé as in a whole region of production of the species. Debating the different drivers that foster the genetic diversity in planted urban trees, the study argues that cities and urban dwellers can unconsciously act as effective guardians of indigenous tree genetic diversity