Diversity and conservation of traditional African vegetables: Priorities for action

© 2020 The Authors. Diversity and Distributions published by John Wiley & Sons Ltd.Aim: Traditional 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. Location: Sub-Saharan Africa. Methods: 126 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. Results: Of 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 conclusions: Areas 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.publishedVersio

Diversity and conservation of traditional African vegetables: Priorities for action

Aim: Traditional 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. Location: Sub-Saharan Africa. Methods: 126 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. Results: Of 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 conclusions: Areas 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

Comparative analysis of management practices and end-users' desired breeding traits in the miracle plant [Synsepalum dulcificum (Schumach & Thonn.) Daniell] across ecological zones and sociolinguistic groups in West Africa

Background: Understanding end-users' preferred breeding traits and plant management practices is fundamental in defining sound breeding objectives and implementing a successful plant improvement programme. Since such knowledge is lacking for Synsepalum dulcificum, a worldwide promising orphan fruit tree species, we assessed the interrelationships among socio-demography, ecology, management practices, diversity and ranking of desired breeding traits by end-users of the species (farmers, final consumers and processing companies) in West Africa. Methods: Semi-structured interviews, field-visits and focus groups were combined to interview a total of 300 farmers and final consumers belonging to six sociolinguistic groups sampled from three ecological zones of Benin and Ghana. One processing company in Ghana was also involved. Data collected included socio-demographic characteristics; crop management systems and practices; and preferences of farmers, final consumers and processing companies and ranking of breeding traits. Data were analysed using descriptive statistics, independence, and non-parametric tests, generalized linear models, multi-group similarity index and Kendall's concordance coefficient. Results: Men (86.33% of respondents) were the main holders of S. dulcificum in the study area. The three most frequent management practices observed in the species included weeding, fertilization and pruning, which were applied by 75.66%, 27.33% and 16.66% of respondents, respectively. The management intensity index varied significantly across ecological zones, sociolinguistic groups, and instruction level (p 0.05). General multigroup similarity indices (CTS ) for farmer-desired traits, on one hand, and final consumer-desired traits, on the other hand, were high across ecological zones (CTS ≥ 0.84) and sociolinguistic groups (CTS > 0.83). Nevertheless, respondents from the Guineo-Congolian (Benin) and the Deciduous forest (Ghana) zones expressed higher agreement in the ranking of desired breeding traits. Preference for breeding traits was 60% similar among farmers, final consumers, and processors. The key breeding traits desired by these end-users included in descending order of importance big fruit size, early fruiting, high fruit yielding (for farmers); big fruit size, high fruit miraculin content, fruit freshness (for final consumers); and high fruit miraculin content, big fruit size, high fruit edible ratio (for processing companies). Conclusion: This study revealed stronger variations in current management practices across ecological zones than across sociolinguistic groups. A high similarity was shown in end-users' preferences for breeding traits across the study area. Top key traits to consider in breeding varieties of S. dulcificum to meet various end-users' expectations in West Africa include fruit size and fruit miraculin content. These results constitute a strong signal for a region-wide promotion of the resource

The World Vegetable Center Amaranthus germplasm collection: Core collection development and evaluation of agronomic and nutritional traits

Amaranth (Amaranthus spp.) is an underutilized crop increasing in popularity as a grain and as a leafy vegetable. It is rich in protein, minerals, and vitamins, and adapts well to a range of production systems. Currently, the lack of improved cultivars limits the use of the crop. Breeding-improved cultivars requires access to large collections of amaranth biodiversity stored in genebanks. The task of searching such vast collections for traits of interest can be eased by generating core collections, which display the diversity of large collections in a much smaller germplasm set. The World Vegetable Center amaranth collection contains around 1,000 accessions of 13 species; among them, there are 281 accessions of four species important for use as vegetable amaranth in Africa (A. cruentus, A. hypochondriacus, A. caudatus, and A. dubius). Based on single nucleotide polymorphism (SNP) marker genotype diversity, a core collection (CC) of 76 accessions, cultivars, and selections was assembled. To a large extent, it represents the diversity of the whole collection. The CC was evaluated for yield and nutritional parameters during the cool and warm seasons in Tanzania and Taiwan and a pretest for variation of drought tolerance in the CC has been performed. Cultivar Madiira 2, an improved cultivar developed for vegetable production in Africa, outperformed all other tested cultivars in terms of yield stability, but several CC accessions had higher yield, lower wilting score, and higher nutrient content than Madiira 2. This indicates the core collection can be used for further improvement of amaranth cultivars