Virtually all bananas traded internationally are of a single variety - the Cavendish - the genetic roots of which lie in India.

The Cavendish crop has been threatened by pandemics of diseases such as that caused by the black sigatoka fungus, the New Scientist reported in its latest issue.

The main hope for survival of the variety lies in developing new hybrids resistant to the fungus, but this is a difficult and time-consuming task because the seedless modern fruit does not reproduce sexually and has to be bred from cuttings, the report said.

The Food and Agriculture Organisation (FAO) has warned that wild banana species are rapidly going extinct as Indian forests are destroyed, while many traditional farmers’ varieties are also disappearing.

And now it could take a global effort to save the bananas’ gene pool.

In fact, many of the genes that could save the Cavendish may already have been lost, said NeBambi Lutaladio, a plant scientist at the FAO’s headquarters in Rome.

One variety that contains genes that resist black sigatoka survives as a single plant in the botanical gardens of Kolkata, he said.

Damage to banana fruit by banana rust thrips

The mist blower being used to spray leaf spot diseases of bananas

Technologies have been developed for banana transformation at the John Innes Centre (Norwich, UK). Shoot tip cultures were used for the production of AAA highland Ugandan banana plants and immature inflorescences at the Centre. Embryogenic calli and cell suspension cultures have been successfully produced from immature flowers. Banana plants were regenerated from these embryogenic cell suspension (ECS) at very high frequency. Transformed banana plants were produced and transgene structure and expression have been monitored in these plants. Such technology will be used to support publicly funded research on banana improvement.