Switching varieties helps banana plants overcome Panama TR4 epidemic

Bananas are currently a major fruit crop and also belong to the group of Vietnam's most important exported fruits. The global market for Vietnamese bananas is wide open, creating great expectations for this industry. However, the development of the banana industry still faces many challenges, especially Fusarium wilt - Panama disease. Within the framework of the Forum 'Solutions for Preventing and Controlling Fusarium Wilt in Bananas', Dr. Chih-Ping Chao, former Director of the Taiwan Banana Research Institute, shared experiences in controlling the disease from the Philippines.

According to Dr. Chih-Ping Chao, TR4 is a soilborne fungal strain capable of surviving for decades, spreading through planting material, soil, irrigation water, vehicles, and people. Once it appears, chemical measures are virtually ineffective, and destroying the farm only helps contain the area but cannot sterilize the soil.

In the Philippines, TR4 was recorded on Cavendish bananas starting in 2000, quickly spreading to low-lying areas. By 2013, thousands of hectares had become unusable for cultivation, with smallholders suffering the heaviest impact. Instead of continuing to expand into new areas to offset losses, a path that increases the risk of pathogen dispersal, the Philippines decided to rehabilitate infected areas using resistant varieties.

The Formosana variety (GCTCV-218), developed from somaclonal variation (changes in genetic characteristics or morphology that occur in the vegetative cells of a plant, often associated with tissue culture and possessing genetic stability) of Cavendish, was created and developed by the Taiwan Banana Research Institute (TBRI). Data shows that GCTCV-218 and GCTCV-219 have a very low TR4 infection rate in heavily infected commercial planting blocks. During the 2012-2015 period, many GCTCV-219 blocks were almost infection-free, while the common Cavendish variety like Grand Naine had an infection rate of up to 87% under the same conditions.

"Although yields and some agronomic parameters have not yet reached the level of susceptible varieties, the new varieties are assessed to be capable enough to restore production, especially in areas where crop rotation is not feasible. By 2025, the total area of Cavendish bananas infected with TR4 that has been rehabilitated using the Formosana variety in the Philippines has exceeded 10,000 hectares. This result was also partly achieved thanks to plant health management measures. Primarily, this involves biological control and the technique of destroying diseased plants at 'hotspots,' combined with treating plant tissues after cutting to limit the source of infection. Measures to prevent microbial re-entry are also applied, such as biological barriers, vehicle disinfection, and surface drainage.

Another crucial point is the planting material. The varieties used are tissue-cultured, which helps to cut off the most common transmission route of TR4 through uncontrolled planting material. Scientists also recommend that growers consider integrating banana cultivation with paddy rice or taro crop rotation to reduce fungal density in the soil, amending the soil with organic materials, or using mulching and intercropping to limit erosion and spread via runoff," the former Director of the Taiwan Banana Research Institute shared.

Compared to the Philippines, Viet Nam faces similar challenges but on a smaller and more decentralized scale. The domestic banana industry is growing, but its reliance on susceptible varieties like Cavendish is quite large, posing a risk in the long term.

To cope with the disease situation, Viet Nam has actively participated in training conferences and activities of international organizations such as BAPNET (Banana Asia Pacific Network) and Bioversity to seek common countermeasures. Scientific research has been enhanced through the publication of in-depth reports on the disease, while personnel have been sent to study and exchange experiences at international research institutes.

Domestic research has successfully selected several lines with moderate resistance, such as GL3-5 from the somaclonal variation of Williams, which was assessed to meet agronomic and quality requirements after trials in the Northern region.

In addition, U&I Agriculture Joint Stock Company (Unifarm) has successfully developed the UNI 126 banana variety. This variety exhibits over 95% resistance to Panama TR4 disease, achieves a yield of 50-65 tons/hectare/crop, and has now been expanded to more than 1,500 hectares at Unifarm and its affiliated units.