Giant bananas of the Ethiopian Highlands

Illustration by Eleanor Hammond-Hunt.

In highland Ethiopia, a giant banana relative provides staple food for 20 million people. Its versatility and resilience, in a country that unenviably is the world’s largest historic recipient of food aid, has earned it the title of ‘the Tree Against Hunger’. Yet outside of its narrow zone of cultivation in the South West Highlands, this remarkable plant is barely known.

The Ethiopian banana, or enset as it is commonly known in Ethiopia, is a giant herb that can grow to over 10 metres in height, with a pseudostem made of tightly overlapping leaf stalks a metre in diameter. Underground it invests energy into a large starchy corm that can weigh 100 kilograms.

Unlike the familiar bananas (Musa) that originated in Asia, it is not the fruits of enset that are consumed – instead the pseudostem is scraped for pulp, the corm pulverized and the whole mixture fermented for up to several months. The result is then made into a variety of foods, the most common being a type of chewy fibrous bread called kocho. The leaves are used for wrapping and the midribs and petioles for fodder or thatch, whilst a strong fibre is a co-product of processing. The fruit, surprisingly, is the only part that is not really used, as it is full of black bullet-like seeds and the plant is usually harvested before flowering.

Women harvesting enset. © James Borrell.

So why are we interested in enset? From a food security perspective, its mode of cultivation is unusual. Enset can be planted or harvested it at any time of the year, is clonally reproduced and tolerant of a wide range of environmental conditions. As a monocarpic perennial, enset will continue to grow over several years until eventually it will flower once (perhaps after 7–12 years), and then die. This multi-year flexibility in choosing when to harvest helps communities to buffer seasonal food insecurity. In South West Ethiopia, enset grows in a region with 48 ethnic groups and 88 recorded languages, making accumulating information about enset’s unusual agronomy rather challenging – and here we have relied on our long running collaboration with many researchers across Ethiopia and elsewhere. In our recent paper, we attempted to draw together disparate ethnobotanical information (as a baseline data resource) for the entire enset research community.

A small house completely surrounded by enset. © James Borrell.

We show that enset has a wide native distribution from East to Southern Africa, but that it has only ever been domesticated in Ethiopia. We collate for the first-time national statistics that show both yield and hectares in production have increased – though we highlight that though the trends are probably valid, these data should be treated with caution. And we show clearly that it is among the most productive crops in Ethiopia, with a heavy bias towards home consumption, use as fodder and for wages in kind. Farmers also reported that as a fermented product, it stores well in the ground without spoiling, providing yet more flexibility in the timing of consumption.

Houses surrounded by enset, viewed from above. © James Borrell.

Previous researchers have found it notoriously difficult to evaluate yield and production in enset when using methodologies developed for other field crops. Enset is transplanted up to five times, intercropped at various densities, harvested irregularly and the impact of pests and diseases (e.g. mealybug and bacterial wilt) are poorly known. Then, of course, there is the spectacular genetic and phenotypic diversity, very little of which has been described or understood. We know of more than 1500 named varieties, with many specialised for particular uses, with correspondingly different growth and maturation rates. Early indications suggest that this genetic diversity is also mirrored in diversity in nutritional and micronutrient composition. In addition to food, a host of red leaved varieties are used for traditional medicines.

A farmer uses part of an enset plant as fodder for his cattle. © James Borrell.

We are always cautious about touting one particular species as a new wonder-crop, especially as there is a huge diversity of underutilised species with potentially beneficial traits. Nevertheless, enset deserves more recognition for fulfilling an unusual trait space that can help enhance the resilience of communities.

Looking to the future, Ethiopia has already warmed by 1.3 °C and farmers are reporting the impacts of climate change. As a highland crop, how will this affect Enset? Will it lose out to a growing influx of introduced crops? Perhaps enset’s remarkable food security attributes could be applied elsewhere in Sub-Saharan Africa? After all, Asian bananas turned out to be quite successful.

Read the paper: Borrell, JS, Goodwin, M, Blomme, G, et al. Enset‐based agricultural systems in Ethiopia: A systematic review of production trends, agronomy, processing and the wider food security applications of a neglected banana relative. Plants, People, Planet. 2020; 2: 212– 228. doi: 10.1002/ppp3.10084

James Borrell
Research Fellow
Royal Botanic Gardens, Kew

Dr James Borrell is a conservation scientist, and science communicator with a passion for adventurous expeditions and conservation fieldwork. His research focuses on combining cutting edge genetic and genomic methods with high resolution environmental niche modeling to guide conservation and agricultural interventions.