Fusarium wilt (aka Panama Disease) tropical race 4 (TR4) is the greatest threat to the ongoing viability of the commercial Cavendish banana industry in many parts of the world, including Australia, and particularly the export industries based in Central and South America. TR4 also poses a major threat to small holder production as it has the capacity to kill more than 50% of the bananas grown worldwide. TR4 originated in southeast Asia and is continuing its movement inexorably through the banana growing continents.
The distribution of TR4 at Jun 2021 image available from https://www.promusa.org/Tropical+race+4+-+TR4
The Banana Biotechnology program has developed transgenic Cavendish bananas resistant to this devastating soil-borne fungus. These TR4-resistant bananas are currently near the end of their second round of field trial evaluation at our trial site in the Northern Territory of Australia. The results describing the development of these plants and their performance in the initial field trial have been published in Nature Communications. One line has been identified with near immunity to TR4 and virtually no negative impact on yield. This line is being progressed through to deregulation in Australia.
The recent detection in Colombia and Peru demonstrates the serious threat of TR4 to the global banana export trade which is based primarily in South and Central America. We have now moved into Phase 2 of our TR4 Cavendish resistance program. In collaboration with Fresh Del Monte and Hort Innovation, we are using gene editing (CRISPR-Cas9) to generate Cavendish with resistance to TR4 and we expect that the first of these lines will be in field trials commencing in 2023.