Scientists have since the 1920s tried to breed bananas that are resistant to pests and diseases. They have had limited success because very little is known about the wild types of bananas, and the asexual (seedless) nature of banana reproduction.
As research into the wild relatives of bananas continues, banana producers are increasing looking to tissue culture as a reliable source of healthy planting materials that could boost production.
Tissue culture, also referred to as micro-propagation, is a way of helping plants that do not produce seeds such as the banana to reproduce. It involves taking a small piece of a shoot tip, leaf or other parts of the plant, cutting it up into tiny pieces that are then germinated in a sterile medium (culture) containing nutrients required for growth such as glucose and vitamins.
Different hormones are added to the new plantlets at different stages of growth to induce vigor, hasten growth, to enhance prolific shoot formation and induce root development.
Tissue culture is undertaken in specialized laboratories where high standards of sterility are enforced to ensure new plantlets are completely free of pests and disease agents like bacteria and fungi.
In the case of bananas, tissue culture effectively eliminates weevils and nematodes, bacterial diseases such as the Bacterial Xanthomonas Wilt (BXW) and fungal diseases like Fusarium Wilt and Sigatoka. Tissue culture has been shown to bring down the cost of controlling foliar diseases by half.
It however does not eliminate viruses that cause diseases like the banana streak and banana bunchy top disease.
Once the new banana plantlets sprout, they are nurtured in the laboratory for couple of weeks or so before being taken to a green house for hardening. After two months and at 30cm high, the plantlets are ready for planting on-farm.
In comparison with the conventional use of suckers, the tissue culture technique dramatically speeds up the multiplication process. In Kenya, about 2,000 healthy plantlets are produced from a single shoot compared to ten suckers from a single banana plant within six months.
Tissue culture banana grows faster, fruiting within 340 days compared to 420 days for conventional bananas. They produce fruit within the first year, subsequent crops also maturing earlier, and therefore easily doubling yields of from conventional bananas. As farmers are trained on better crop management, tissue culture banana have a better on-farm survive rate.

For more information on banana diseases, visit: http://bananas.bioversityinterantional.org