Solutions discussed for sustainable cassava development

According to the Department of Agriculture and Rural Development of Tay Ninh province, the province currently has the second-largest cassava growing area in Vietnam after Gia Lai but the highest cassava yield in the country. The province’s cassava growing area is now about 59,000 ha, accounting for 22.1 per cent of its total agricultural production area.

As of March 18, 2022, the total cassava production area is 46,613 ha. The area infected with leaf mosaic disease is 36,968 ha, accounting for 79.3 per cent of the cassava area of the province.

This year, Tay Ninh province has implemented an intensive cultivation model of cassava, with a total area of ​​6 hectares, using HN3 and HN5 resistant varieties, implemented in Chau Thanh, Tan Chau, and Duong Minh Chau districts.

The province co-operated with Hung Loc Agricultural Research Centre to test seven new varieties of cassava resistant to leaf mosaic disease. Until now, cassava is nearly 4 months old, in the development stage of tubers. The province coordinated with the Institute of Genetics to assess the adaptability of cassava varieties HN1 and implemented rapid propagation of cassava varieties HN3 and HN5 by propagation method in greenhouses to replace severely ill cassava varieties.

Nguyen Dinh Xuan - Director of the Department of Agriculture and Rural Development of Tay Ninh province said that Tay Ninh farmers have adapted very quickly since the cassava mosaic disease appeared and broke out.

As soon as cassava mosaic disease appeared in 2017, Tay Ninh authorities and farmers agreed to drastically implement the "zero diseases" policy. However, cassava leaf mosaic is a new, dangerous, and rapidly spreading disease. Tay Ninh province has found a solution to cope with the epidemic.

“ We deployed solutions synchronously to respond to the disease and search for disease-free cassava varieties,” he said.

“Besides the two varieties that have been recognised by the Ministry of Agriculture and Rural Development - HN3 and HN5, four more varieties are about to be recognized. Among them, the HN1 variety is very promising as it can achieve a tuber yield of up to 50 tonnes per ha with a high content of starch," said Xuan.

Xuan added that these cassava varieties still needed further studies on other indicators. For example, in addition to resistance to cassava leaf mosaic disease, these varieties are also resistant to other diseases such as dragon broom disease, stem pus disease, and root rot disease.

“Once the results are very good, agricultural authorities will introduce them to people, not only in Tay Ninh but also the whole country,” he said.

Speaking at the workshop, Nguyen Hoan - Chairman of the VAC  Association of Tay Ninh province said that leaf mosaic disease was caused by powdery mildew virus,  sp besides research on the hybridisation of mosaic resistant varieties, it was necessary to have effective disease prevention measures.

A representative of the Plant Protection Department of the Ministry of Agriculture and Rural Development said that, up to now, people had not been able to control the mosaic epidemic but just identified some problems including backward farming, and improper attention to disease prevention measures. Moreover, seed trading has not been strictly controlled, resulting in substandard seeds being sold widely.

Few mosaic-resistant varieties have been found so research units need to transfer to reputable and capable enterprises for rapid propagation. Local authorities should help raise awareness for farmers while the department will strengthen domestic quarantine and join hands with farmers on safe farming techniques to step by step repel the disease.

According to Prof. Dr. Le Huy Ham - Director of the Institute of Agricultural Genetics, creating a new variety usually takes 7-10 years. However, it only took us three years to find new varieties that reached record speeds.

 “In the joint effort, the direction of international cooperation in production, research on cassava breeding has made an important contribution to the creation of disease-resistant varieties today.

Tran Van Chien, Vice Chairman of Tay Ninh Provincial People's Committee said that cassava was a traditional crop that brings high economic efficiency compared to many other crops in the locality. The emergence of cassava leaf mosaic has severely affected the cassava industry in the country.

“Creating a breakthrough in productivity, output, and sustainable benefits for cassava in the future is an urgent issue,” he said.

“This workshop is a meaningful activity to evaluate the genome of cassava varieties resistant to leaf mosaic disease; develop research activities to respond to more dangerous diseases in the future and then, propose solutions for sustainable development of cassava for the Southern region", Chien said.

Previously, the People's Committee of Tay Ninh province in collaboration with the International Centre for Tropical Agriculture (CIAT) organised a visit to the successful new mosaic resistant cassava varieties and the propagation model by the greenhouse method in Tan Chau district.

According to CIAT, this activity is aimed at evaluating the genome of cassava varieties resistant to leaf mosaic disease, creating a basis to continue building research activities to respond to more dangerous diseases on cassava plants that may occur. It also introduced rapid propagation technology and proposed solutions for sustainable cassava development for the Southern region.

Activities within the framework of the project to establish solutions to treat cassava diseases in Southeast Asian countries, funded by the Australian Center for International Agricultural Research (ACIAR) in the period 2019-2023.