Modelling potential range expansion of an underutilised food security crop in Sub-Saharan Africa

Koch, Olef; Mengesha, Wendawek Abebe; Pironon, Samuel; Tim, Pagella; Ondo, Ian; Rosa, Isabel M.D.; Wilkin, Paul; Borrell, James S.

doi:10.1088/1748-9326/ac40b2

Cited by 22 publications

(20 citation statements)

References 79 publications

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“…Increased genetic load, which remains hidden in heterozygotes during clonal reproduction, could also be one of the factors maintaining clonal propagation as the preferred agronomic system. Whilst this strategy may have been optimal in the recent Holocene, a period of relative climate stability, we know that Ethiopia is already experiencing a warming climate, and that climate impacts are projected to become more severe throughout this century (Koch et al, 2022;McSweeney, New, & Lizcano, 2010). We suggest that for enset, and clonal crops more widely, the trade-off between clonal propagation and sexual recombination may shift further towards the latter under climate change.…”

Section: Discussionmentioning

confidence: 95%

Maintenance and expansion of genetic and trait variation following domestication in a clonal crop

White¹,

Biswas²,

Abebe³

et al. 2022

Preprint

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Clonal propagation enables favourable crop genotypes to be rapidly selected and multiplied. However, the absence of sexual propagation can lead to low genetic diversity and accumulation of deleterious mutations, which may eventually render crops less resilient to pathogens or environmental change. To better understand this trade-off, we characterise the domestication and contemporary genetic diversity of Enset (Ensete ventricosum), an indigenous African relative of bananas (Musa) and principal starch staple for 20 million Ethiopians. Wild enset is strictly sexually outcrossing, but in cultivation is exclusively propagated clonally and associated with diversification and specialisation into hundreds of named landraces. We applied tGBS sequencing to generate genome-wide genotypes for 192 accessions from across enset’s cultivated distribution, and surveyed 1340 farmers on enset agronomic traits. Overall, reduced heterozygosity in the domesticated lineage was consistent with a domestication bottleneck that retained 37% of wild diversity. However, excess low frequency putatively deleterious missense mutations present as heterozygotes suggested accumulation of mutational load in clonal domesticated lineages. Our evidence indicates that the major domesticated lineages initially arose through historic sexual recombination associated with a domestication bottleneck, followed by amplification of favourable genotypes through an extended period of clonal propagation. Among domesticated lineages we found significant phylogenetic signal for multiple farmer identified food, nutrition and disease resistance traits and little evidence of contemporary recombination. Development of future-climate adapted genotypes may require crop breeding, but outcrossing risks exposing deleterious alleles as homozygotes. This trade-off may partly explain the ubiquity and persistence of clonal propagation over recent centuries of comparative climate stability.

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Section: Discussionmentioning

confidence: 95%

Maintenance and expansion of genetic and trait variation following domestication in a clonal crop

White¹,

Biswas²,

Abebe³

et al. 2022

Preprint

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show abstract

“…In the future, emerging climate and demographic pressures may require the relatively rapid shift and rearrangement of current crop distributions (Sloat et al ., 2020; Koch et al ., 2022), as well as adoption of new and better adapted species and agrisystems (Pironon et al ., 2019; Borrell et al ., 2020). In Ethiopia, the long-term maintenance of crop diversity over multiple periods of origin, combined with rapid integration of novel species suggests that these agrisystems may be relatively adaptable and resilient.…”

Section: Discussionmentioning

confidence: 99%

Introduced crops supplement rather than replace indigenous crops in an African center of agrobiodiversity

Rampersad

Geto

Samuel

et al. 2022

Preprint

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Crop diversity plays a major role in underpinning food security. It is especially important to smallholder and subsistence farmers, who often rely on crop diversity for stable and resilient production. Despite this, global expansion of a small pool of major crops and the associated homogenisation of global agricultural systems may decrease on-farm crop diversity. We surveyed 1,369 subsistence farms stratified across climate gradients in the Ethiopian Highlands, to characterise the richness and cultivated area of the 83 edible crops they contained. We further categorise these crops by their period of introduction to Ethiopia. We apply non-metric multidimensional scaling and mixed effects modelling to characterise agrisystem composition and test the impact of crop introductions. We find a significant positive relationship between introduced and indigenous crop richness, suggesting that crop introductions have tended to supplement rather than replace or reduce indigenous crop diversity. Geographically matched farms with higher proportions of introduced crops, had significantly higher overall crop richness. Analysis of socio-economic drivers indicates that both poverty and low accessibility are associated with reduced cultivation of modern introductions. We conclude that global patterns of major crop expansion do not necessarily result in agrobiodiversity loss for subsistence farmers, in our Ethiopian case study. Importantly, socioeconomic factors may strongly influence the farmers propensity to adopt novel species, suggesting targets for agricultural extension policies. Given the rapid climatic, economic and demographic changes impacting global food systems and the threats to food security these entail, robust indigenous agricultural systems supplemented with diverse introduced crops may enhance resilience.

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“…It has cultural significance and helps to stabilize soils and microclimates [74] . According to recent research, enset, an Ethiopian plant related to the banana, has the potential to feed more than 100 million people in warmer climates if its production has extended [75] .…”

Section: Ensetmentioning

confidence: 99%

Review of the Role of Orphan Crops in Food Security

Feyisa¹

2022

Res. World Agric. Econ.

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Ethiopia is one of the most populated countries in Africa. Agriculture employs over 70% of the population. It is dominated by small-scale farmers who practice rain-fed mixed farming by using traditional technology, adopting a low input and low output production system. As a result, it is vulnerable to adverse weather conditions. Cereal crops provide food for majority Ethiopians, so most agricultural transformation plans prioritize increasing cereal crop productivity. However, about five million people experience food insecurity each year and require support. Population growth, environmental degradation, conflict, and climate change are the most serious threats to nation’s food security. In a time when the food supply cannot keep up with population expansion, there is a need for holistic solutions to development-related issues such as food insecurity, malnutrition, and poverty. Despite Ethiopia being a center of origin and diversity for several food crops, the potential benefits of underutilized indigenous crops are yet not exploited. However, they can play a significant part in human nutrition, income, and medicinal value. As a result, crop diversification may be the best choice for achieving household food security. One way to help nation’s food systems diversify is to include more orphan crops. Even though a small portion of the country’s land is dedicated to underused crops, more than 20% of the population relies on them for food. Orphan crops, such as enset, which can feed 100 million people, can help to attain food security in Ethiopia. As a result, promoting and researching these crops is the most sustainable strategy for lowering and managing poverty and food insecurity in Ethiopia.

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Modelling potential range expansion of an underutilised food security crop in Sub-Saharan Africa

Cited by 22 publications

References 79 publications

Maintenance and expansion of genetic and trait variation following domestication in a clonal crop

Maintenance and expansion of genetic and trait variation following domestication in a clonal crop

Introduced crops supplement rather than replace indigenous crops in an African center of agrobiodiversity

Review of the Role of Orphan Crops in Food Security

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