Diversity and conservation of traditional African vegetables: Priorities for action

Maarten Van Zonneveld,Ian K Dawson,Sognigbé N'Danikou,Svein Ø Solberg,Roeland Kindt,John Lambrinos

doi:10.1111/ddi.13188

Abstract

AbstractAimTraditional African vegetables have high potential to contribute to healthy diets and climate resilience in sub‐Saharan African food systems. However, their genetic resources are likely at threat because they are underutilized and under the radar of agricultural research. This paper aims to contribute to a conservation agenda for traditional African vegetables by examining the geographical diversity and conservation status of these species.LocationSub‐Saharan Africa.Methods126 traditional annual and perennial African vegetables were selected for their food and nutrition potential. Food uses and species’ areas of origin were recorded from literature. Species’ presence records were collected from open‐access databases of genebanks and herbaria. These records were used to determine geographical patterns of observed and modelled richness, to distinguish geographical clusters with different compositions of vegetables, to assess species’ ex situ and in situ conservation status and to prioritize countries for conservation actions.ResultsOf the 126 species, 79 originated in sub‐Saharan Africa. High levels of observed and modelled species richness were found in: (a) West Tropical Africa in Ghana, Togo and Benin; (b) West‐Central Tropical Africa in South Cameroon; (c) Northeast and East Tropical Africa in Ethiopia and Tanzania; and (d) Southern Africa in Eswatini. South Sudan, Angola and DR Congo are potential areas of high species richness that require further exploration. In general, ex situ conservation status of the selected species was poor compared to their in situ conservation status.Main conclusionsAreas of high species richness in West Tropical Africa, South Cameroon and Ethiopia coincide with centres of crop domestication and cultural diversity. Hotspots of diversity in Tanzania and Eswatini are especially rich in wild vegetables. Addressing the conservation of vegetable diversity in West Tropical Africa and South Cameroon is of most urgent concern as vegetable genetic resources from these locations are least represented in ex situ collections.

Highlights

Sub-Saharan Africa (SSA) has some of the areas of highest hidden hunger in the world, with these acute nutritional deficiencies exacerbated by climate change (von Grebmer et al, 2014)
Values in bold are the top-ten highest values; A75: upper quartile value of observed richness; Ar100: maximum value of observed richness corrected by resampling without replacement; Ar75: upper quartile value of observed richness corrected by resampling without replacement; Am100: maximum value of modelled richness; Am75: upper quartile value of modelled richness; ΔAb: differences between the number of observations of the selected species and genebank accessions collected per country; ΔA: number of observed species, for which germplasm is not yet collected in a country for ex situ conservation; cluster: the dominant cluster of vegetable composition in a country; region of crop diversity: region of crop diversity where the country is located following level two of the World Geographical Scheme for Recording Plant Distributions. nd: no data available
Our analysis shows that Madagascar has a similar vegetable composition to West and West-Central Tropical Africa and is rich in domesticated vegetables, while relatively poor in semi-domesticated and wild vegetables

Summary

| INTRODUCTION

Sub-Saharan Africa (SSA) has some of the areas of highest hidden hunger in the world, with these acute nutritional deficiencies exacerbated by climate change (von Grebmer et al, 2014). In a revised research and development agenda, traditional African vegetables have high potential to contribute to food production diversification and healthier diets in SSA. These vegetables are naturalized (introduced long ago and accepted as “traditional”) or indigenous to SSA and are adapted to local food and farm systems after generations of interactions with humans and the environment. These migrations result in reduced human populations in rural areas and drive the loss of traditional knowledge about these species, as well as the loss of local landraces and populations because of reduced use (Keller et al, 2005; Pilling et al, 2020) These losses are exacerbated by limited research. We propose ex situ and in situ conservation of a minimum of 50 populations per species (following Brown & Marshall, 1995), while at the same time maintaining diverse ex situ collections of at least 200 genebank accessions and ideally 1,000 or more accessions for those species with high cultivation and breeding potential; (c) Prioritized actions: countries and conservation actions will be prioritized with a focus on multiple-crop germplasm collecting missions for ex situ conservation; (d) Scoring rules: a clear rational is provided for the selection of the 126 species, and we apply a set of indicators to assess and compare the ex situ and in situ conservation status of each species and to prioritize countries for conservation actions; (e) Transparency: scoring is explained in detail and the R coding we use can be requested for verification of our results or to apply to other geographical regions or crop groups; and (f) Risks need to be managed by establishing standard operating procedures to ensure the safety of people when they implement conservation actions, and by establishing germplasm backups, such as at the Global Seed Vault in Svalbard

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Findings

| CONCLUSIONS