International cooperation is key to solving disease-resistant cassava

On March 31, in Tay Ninh, the Institute of Agricultural Science for Southern Viet Nam (IAS), in collaboration with the Alliance of Bioversity International and CIAT and the Tay Ninh Department of Agriculture and Environment, hosted the 2026 International Workshop on Cassava Breeding and Disease Surveillance Network in Asia. The event drew a large number of scientists and experts from across the region, raising expectations for a more sustainable restructuring of the cassava sector.

The billion-dollar cassava industry faces a ‘disease storm

Dubbed the country’s “cassava capital,” Tay Ninh maintains a stable cultivation area of about 61,000 - 62,000 hectares, with annual output exceeding 2 million tons, accounting for nearly 20 percent of national cassava production. With more than 60 processing plants and a total capacity of over 6.4 million tons of fresh roots per year, the province plays a central role in the industry’s value chain.

However, growth momentum is being seriously threatened by disease outbreaks. As of March 2026, diseases such as cassava mosaic, root rot, stem base rot, and witches’ broom have spread widely, with infection rates reaching 33.4 percent of the cultivated area, or more than 12,500 hectares.

According to Nguyen Dinh Xuan, Deputy Director of the Tay Ninh Department of Agriculture and Environment, the core issue is not only disease pressure but also the degeneration of earlier generations of disease-resistant cassava varieties. Although seven resistant varieties have been introduced into production, practical results reveal significant limitations.

Some varieties, such as HN3 and HN5, have low starch content. HN97, while resistant to mosaic disease, is prone to root rot and is not accepted by processing factories. HN36 suffers from severe stem exudation, HN80 is difficult to cultivate, and HN1 is susceptible to red spider mites and witches’ broom disease. As a result, only about 10 percent of the area still maintains these varieties.

A rare bright spot is the HLRS-15 variety, officially recognized in early 2025, which has shown good disease resistance and no root rot. However, to meet large-scale production demands, the sector requires more “multi-functional” varieties.

Under pressure from disease and climate change, Tay Ninh has set out specific targets: by 2030, 75 - 90 percent of the area will use disease-free planting material; 80 percent will adopt high technology and mechanization; and 92 percent of output will undergo deep processing aligned with circular economy principles and emissions reduction.

To achieve these goals, the local agricultural sector is counting on support from international organizations to access new genetic resources. Requirements extend beyond resistance to cassava mosaic disease to include tolerance to multiple pests and diseases, adaptability to climate change, and starch content exceeding 27 percent.

“The Department of Agriculture and Environment is committed to creating the most favorable conditions for research results to be rapidly transferred from the laboratory to production,” Xuan emphasized.

International cooperation as the key to the future

At the workshop, the Hung Loc Agricultural Research Center (HARC), under IAS, announced several notable results in breeding new cassava varieties. The research process follows a rigorous four-step protocol: hybrid material creation, preliminary selection, multi-location trials, and comprehensive evaluation.

HARC currently manages a rich pool of breeding materials, with 20 lines under advanced trials, 80 lines under evaluation, and more than 1,500 lines being screened in Dong Nai and Tay Ninh.

Notably, new varieties in the HAC line demonstrate outstanding advantages. HAC-01 and HAC-02 have short growth cycles of 8 months and yields of 50-60 tons per hectare. HAC-03 and HAC-04 maintain a stable starch content of 25 - 28 percent and show strong drought tolerance. In particular, HAC-10 achieves a starch content of 29 - 31 percent, the highest among the introduced lines. These varieties are resistant to cassava mosaic disease and show strong tolerance to root rot and witches’ broom, offering promising replacements for less effective older varieties.

Speaking at the workshop, Dr. Truong Vinh Hai, Acting Deputy Director of IAS, noted that in 2025 Viet Nam’s cassava sector recorded significant milestones: cultivation area exceeded 500,000 hectares, production reached approximately 10.5 million tons, and export turnover hit $1.26 billion USD, maintaining its position as the world’s second-largest cassava exporter.

Cassava has transitioned from a “hunger-relief” crop to a key export commodity, supporting the livelihoods of more than 1.2 million farming households. However, challenges related to disease, soil degradation, and climate change are creating an urgent need for more sustainable sector restructuring.

“With the foundation of established cooperation and close coordination among IAS, the Alliance of Bioversity International and CIAT, and the Tay Ninh Department of Agriculture and Environment, this workshop will lay a solid groundwork for a new phase of collaboration, helping cassava farmers better cope with disease and climate change,” Dr. Truong Vinh Hai said.

Within the framework of the workshop, scientists and experts from across the region focused discussions on three strategic objectives: assessing the current state of the variety system; strengthening regional network connectivity; and guiding breeding toward market demand and biological threats. These efforts are expected to pave the way for a more sustainable restructuring of the cassava sector.