The detection of Panama disease TR4 in Ecuador in September 2025 renewed global concern for the Cavendish banana, which accounts for around half of global production and more than 90 per cent of exports. TR4 is a soil-borne fungus with no known cure. Symptoms often become visible only after the pathogen is established in the soil, limiting intervention options.
Taiwan has been managing TR4 since 1967, when infected banana plants were identified in Pingtung County. According to Su Yu-yen of the Taiwan Banana Research Institute, infected plants show yellowing along leaf edges followed by wilting, while fruit becomes small and misshapen. Early responses included removing infected plants and replanting lateral buds from affected fields, which contributed to further spread.
"Over 80 per cent of banana farms [in Taiwan] are still infected with TR4 today," Su said.
The Taiwan Banana Research Institute adopted a selection-based strategy. Lateral buds from trees showing lower symptom expression were collected and cultivated in laboratory conditions. Large numbers of plantlets were produced and screened. Candidates that appeared resistant were planted in contaminated soil to assess survival under field conditions.
This process led to the identification of the first resistant Giant Cavendish strain, Taiwan Banana No. 1, planted commercially in 1992. Subsequently, seven variants demonstrated resistance while co-existing with TR4. These include Tai-Chiao No. 1 with 80 to 90 per cent resistance, No. 4, No. 5 with 80 per cent resistance, and No. 7.
In 2025, the institute used the Williams variety, also susceptible to TR4, to develop a new variant with 70 per cent resistance to Panama disease.
Taiwan's long-term exposure to TR4 has shaped its breeding and propagation strategies, focusing on resistance selection and field validation. While infection levels remain high across plantations, resistant cultivars have enabled continued production under pathogen pressure.
Source: Focus Taiwan
