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GM bananas to fight wilt in Africa

There is no doubt that farmers and governments have tried to make the most use of available methods to fight banana wilt (see 'Uganda 'needs biotech law' to save banana sector').

But these efforts need to be supported with additional alternatives — developing transgenic banana varieties resistant to banana xanthomonas wilt (BXW) would boost the available arsenal to fight the disease and save livelihoods in the Great Lakes region.

The incomes of millions of farmers in East Africa are threatened by continuing outbreaks of BXW. The disease has been reported in Burundi, DR Congo, Kenya, Rwanda, Tanzania and Uganda, which make up the largest banana producing and consuming African region.

Banana wilt attacks all banana varieties resulting in absolute crop loss. According to a recent impact assessment by the International Institute of Tropical Agriculture (IITA) in Uganda, letting BXW spread uncontrolled could cost the country's economy up to $200 million per year.

The most commonly recommended measures for managing BXW involve a set of practices that include removing the male flowers, disinfecting farming tools and using healthy planting materials. When well practiced these methods have succeeded in reducing the disease's spread.

But although over 85 per cent of Ugandan farmers are aware of these measures, a recent study shows that less than 35 per cent carry them out. Thus these practices alone might slow but not stop the spread of BXW, a goal that requires developing other options to be integrated into ongoing disease management efforts across East Africa.

For diseases like BXW that spread rapidly with total yield loss, developing resistant varieties is an economical and more sustainable option.

It is also one that faces challenges. To date, no useful source of resistance has been identified in banana genetic material and conventional breeding of the crops remains a difficult and lengthy process.

One approach being explored is to transform farmer-preferred banana cultivars by introducing a resistance gene from sweet pepper. Such an initiative is spearheaded by the IITA in collaboration with Uganda's National Agricultural Research Organisation, the Kenya-based African Agricultural Technology Foundation and Academia Sinica in Taiwan.

Priority has been given to the major farmer-preferred banana varieties, including Kayinja. The improved varieties will be tested rigorously for efficacy against BXW and for environmental and food safety in compliance with regulations of each of the countries where such bananas could be grown and consumed.