Testing cassava varieties free from mosaic disease

This is a research product of the Institute of Agricultural Science and Technology South Central Coast (ASISOV) under the research project“Research on seed selection and development of a process for quickly multiplying cassava varieties free from mosaic disease by bud multiplication method in Binh Dinh province”.

HN1 cassava variety with good resistance to leaf mosaic disease, fresh tuber yield of 34.4 tons/ha and starch content of 25.1% is opening up new prospects for Binh Dinh cassava industry in the fight against the disease. is spreading.

Dr. Vu Van Khue, Deputy Director of ASISOV, said he and his colleagues tested 8 cassava varieties including HN1, HN3, HN5, C97, HLS14, KM505-54, KM94, KM94-1 at 3 points in the province with an area of ​​3,600 m2. . The testing sites were selected in key cassava growing areas: Binh Tan commune (Tay Son district), My Tai commune (Phu My district) and Hoai Hao commune (Hoai Nhon town) to evaluate the adaptability of the variety. under actual production conditions.

After 7 months of monitoring and evaluation, the research team has identified 4 promising varieties: HN1, HN3, HN5 and C97. In particular, the HN1 variety shows many outstanding advantages. “When intercropped with cassava plants infected with wilted leaf mosaic disease, the HN1 variety still grows healthily with lush dark green color, tall stems, and regular lush leaves. Actual inspection shows that each plant has 5-10 tubers arranged regularly, large, long tubers, smooth skin, ivory white flesh, firm and smooth – a sign of high starch content. This is a clear difference compared to infected plants 3-4 small tubers, short” – Dr. Khue shared.

Technical indicators also confirm the advantage of the HN1 variety: resistance to leaf mosaic disease at level 1 (highest resistance level), fresh tuber yield reaches 34.4 tons/ha (higher than the provincial average of 7.1 tons/ha). ha), and starch content reached 25.1%. In particular, this variety can also be used as fresh food from tubers to leaves – a rare feature in high-yield cassava varieties. With these advantages, HN1 variety can help people increase profits by over 10% compared to using old cassava varieties that are severely infected with mosaic disease.

In parallel with seed selection, the research team has developed a process for quickly multiplying disease-free varieties. The research was carried out systematically, starting with a survey of influencing factors such as type of cuttings (from 2-5 nodes), growing medium, density and fertilizer.

The model is implemented in two phases: the initial propagation phase in a nethouse with an area of ​​200 m2 and the transition phase to the field with a scale of 2 hectares. The results are especially impressive with the two varieties HN1 and C97, showing outstanding adaptability right from the cutting stage with sturdy plants, strong roots and good growth in the greenhouse. When transferred to the field, the survival rate reached 75%, the tree grew well with a height of 120 cm and especially demonstrated the highest level of resistance to leaf mosaic disease (level 1).

Currently, the project has expanded to a commercial production scale of 10 hectares in three locations: Binh Tan commune (Tay Son district), My Tai commune (Phu My district), and Hoai Hao commune (Hoai Nhon town). According to Dr. Khue, initial results show an increase in economic efficiency of over 10% compared to traditional farming, while meeting the criteria for productivity (over 32 tons/ha) and starch content (over 26%). . This process not only solves the problem of lack of disease-free varieties in production but also demonstrates high sustainability when suitable for local farming conditions and is capable of being replicated for mass production.

MSc. Nguyen Cong Bang, Head of the Crop Management and Plant Protection Department (Cultivation and Plant Protection Branch, Department of Agriculture and Rural Development of the province) commented that the success of this research not only helps control leaf mosaic disease but also opens up sustainable development for the province’s cassava industry. Having disease-resistant varieties and effective breeding processes will ensure a stable source of raw materials for the processing and export industries.

In the coming time, ASISOV will continue to research and optimize farming processes, and organize training for farmers. The goal is to establish a sustainable disease-free breeding system, contributing to improving the value of Binh Dinh cassava industry.

Cassava is one of Binh Dinh’s important industrial crops, playing a key role in the province’s agricultural economic structure. With an annual planting area ranging from 11,358-13,581 hectares and a productivity of 24.6-27.3 tons/ha, cassava not only serves food processing but is also an important raw material for industry and export. password. In particular, for many farming households in the main cassava growing areas of the province, cassava is the main source of income to ensure livelihoods.

However, the province’s cassava industry is facing a big challenge when leaf mosaic disease appeared in 2020 and spread rapidly. According to experts, the disease is caused by a virus of the Geminiviridae family, spread mainly through whiteflies and infected cuttings. Typical symptoms are yellow spots appearing on the leaves mixed with green parts, leaves are deformed, wrinkled and smaller than normal. When heavily infected, plants will be stunted and underdeveloped, seriously reducing productivity by 60-90% if infected from the seedling stage.

According to statistics from the Provincial Department of Agriculture and Rural Development, by May 2021, Binh Dinh had 264.1 hectares of infected cassava, accounting for 3.9% of the total planted area. Of these, there are 140 hectares infected with a rate of 15-30%, 53.1 hectares infected with 30-70% and 14 hectares infected with over 70%. The disease is concentrated mainly in the districts of Vinh Thanh (71 hectares), Hoai Nhon (41 hectares), Tay Son (34 hectares) and Van Canh (25 hectares). Damage was estimated at up to 3,600 tons of fresh cassava, equivalent to 6.5 billion VND. What is worrying is that there is currently no specific medicine, while the spread of the disease is increasingly rapid, directly threatening the sustainable development of the local cassava industry.