Leuven - the banana metropolis


Bananas are the world's most popular fruit. They are grown in Africa, Asia and Latin America. Belgium, however, (and yes, we do mean Belgium), is home to the largest collection of bananas in the world hosted at the KU Leuven's Laboratory of Tropical Crop Improvement. On 23 January 2017 our country will be celebrating the 30th anniversary of the banana genebank. It helps researchers and farmers across the world gain greater insights into banana cultivation.

A whole bunch of varieties

The banana, as we now find it in the shops, has a history spanning no less than 8,000 years. Indeed, this is how long it has taken mankind to reach a natural selection which meets the demands of consumers. Originally, the wild banana was a fruit of just a few centimetres in length and it was full of seeds with little flesh.

In fact, only one sort of banana is now exported: the Cavendish. This is a pity, in Swennen's opinion, as there are so many different varieties that taste far better. Why is that? Western consumers are rather fussy: bananas need to be a lovely yellow colour, have a sweet flavour, be a particular size, … In fact, bananas exist in all kinds of colours and formats. Such bananas are grown in the tropics by small-scale farmers. They use them for their own consumption, selling the rest on local markets.

The green gold of the South

Bananas are a vital food resource for over 500 million people. They are the world's fourth most important crop after rice, wheat and maize. The African population is particularly dependent on this fruit. Not only as food, but also as a source of income.

In addition to the sweet dessert banana that we are used to, bananas also exist for cooking, baking and beer-making. In the tropics nothing from the banana plant is wasted: the flowers and the trunk are used as vegetables, the large leaves are used to cover roofs and the fibres from the trunk are made into clothes. Women in East Africa turn cooking bananas into flour, which is then used as baby food. In Uganda they mash up the flesh of the fruit with the leaves: eaten with a piece of meat and some beans this is a typical national dish called Matoke.

Bananas are big business

Each year, over 145 million tons of bananas are cultivated. Only 15% of these are exported. This means that no less than 85% of all bananas produced in the world are used locally. India is the world's largest producer of bananas, Ecuador exports the most bananas and the United States is the biggest consumer. When it comes to Europe, Belgium takes the lead: we each eat an annual quantity of around 8 kg of bananas. Our country is also the world's second largest importer and exporter of bananas.

The genebank, a transit centre

The banana genebank in Leuven maintains 1,536 varieties of banana. Here, digital information is gathered on each variety and published on the internet, in order to encourage diversity and stimulate use of these plants to help ensure that the various types are not lost for future generations. Indeed, the banana is increasingly threatened with disease and deforestation. Material arriving in Leuven is first made ‘healthy’. Meanwhile, 70% of the collection is free of disease. The lab also carries out research into drought resistance.

The banana does not reproduce using seeds. That's why cuttings from the different varieties are kept in test tubes filled with soil. These are kept in growth rooms at a constant temperature of 15°C with a little light. Using their roots the required minerals, vitamins, proteins and sugars are absorbed. The cuttings are replaced each year.

Professor Swennen explains the daily activities: “We are constantly receiving requests for new varieties via our website. We send off 5 samples of each type for free. In the 30 years that we have been in operation we have sent material to over 109 countries. Our clients include NGOs, universities, research institutions, and, of course, the farmers themselves. How are they sent? Either in plastic bags, or in small plastic pots with a screw top. We encourage partners to set up their own laboratories and establish local plant trading. It is usually private companies who continue to reproduce the material, and then sell it cheaply to the local farmers. So it's a long way from the classic case of subsidies.”

There are around 2,000 varieties available across the globe. The aim is to collect them all in Leuven and to refine the genetic maps of each different variety. Each cutting has a barcode. When this is scanned, all kinds of information appears regarding the identity and the plant's characteristics. The entire collection has also been frozen (using liquid nitrogen at a temperature of -196°C), in order to preserve the diversity eternally. Once defrosted, the small plants remain viable and can continue to grow.

A collection for mankind

Belgium has been researching bananas ever since the year 1910. The fact that there is a historical link between our country and Central Africa, plus KU Leuven's expertise in in vitro culture together with our country's stability means it is not such an illogical choice to house the collection at the KU Leuven. Meanwhile, the collection is part of Bioversity International, a research institute focusing on the preservation of the diversity of agricultural crops. The Belgian Development Cooperation has been supporting banana research for over 40 years.

The genebank is under the auspices of the Food and Agriculture Organization of the United Nations (FAO). Indeed, it is assumed that the collection belongs to mankind. And more specifically to the farmers who originally supplied the material. Customers taking samples from the genebank may therefore not patent them. Should the material ever be commercialised then a part of the profit must be returned to the farmers via the UN.

Focus on farmers

Swennen believes it is important to immerse yourself in the local culture. “You may think that you have the perfect variety, but you also need to see how the farmers react to the plants. For example, if the leaves are too big then they create too much shade for other plants. Small bunches are sometimes preferred because they grow 5 times a year, compared to large bunches which only appear once a year. It is therefore important to offer sufficient choice.”

Following the genocide in Rwanda an enormous flood of refugees came to Tanzania from Rwanda and Burundi. In order to prevent a situation of extreme famine 70,000 plants (24 varieties) were taken from Leuven across to Tanzania. These were planted in the fields and judged by the farmers. They eventually selected 14 of the 24 varieties and produced 6 million plants. It was an enormous success: living conditions improved for half a million people and the farmers tripled their income! “This not only prevented starvation, it also generated considerable trading of both bananas and banana plants within the country itself.
We can inject knowledge, but we must also trust the farmers' traditional skills. That's the only way to achieve a win-win situation,”
confirms Swennen.

Stefanie Buyst

Bioversity International

Bioversity International is a global research-for-development organisation that delivers scientific evidence, management practices and policy options to use and safeguard agricultural and tree biodiversity to attain sustainable global food and nutrition security. The organisation works with partners in low-income countries where agricultural and tree biodiversity can contribute to improved nutrition, resilience, productivity and climate change adaptation. Bioversity International is a CGIAR Research Centre.

CGIAR is a global research partnership for a food-secure future. CGIAR science is dedicated to reducing poverty, enhancing food and nutrition security, and improving natural resources and ecosystem services. Its research is carried out by 15 CGIAR Centers in close collaboration with hundreds of partners across the globe.