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5.1 Cassava varietal improvement

Before 1985, the most popular cassava varieties grown in Viet Nam were Gon, H34 and Xanh Vinh Phu. During the period of 1986–1993 (Table 8), three cassava varieties, HL20, HL23 and HL24, were selected from local cassava collections and released by Hung Loc Agricultural Research Center (HARC). In 1994 they were grown in about 70 000 ha in South Viet Nam (Tran Ngoc Ngoan et ah.,1995).

The Viet Nam Root Crops Program, with strong support from CIAT, has made considerable progress since 1988. The CIAT collaboration with Viet Nam started much later than that with national programs in other countries; yet, the rate of progress in increasing the yield potential of breeding populations has been the fastest (Figure 9). During the period 1993–1995, two new cassava varieties, KM 60 (Rayong 60) and KM 94 (Kasetsart 50), were selected and then named and released for production by the Ministry of Agriculture and Rural Development (MARD) in 1994/95. Among these, KM 94 has been the best variety in all standard yield trials (SYT) at HARC from 1991–1993; it was also evaluated in regional yield trials (RYT) in 25 locations in several provinces in 1994. The variety was released for production in 1994/95 (Hoang Kim et al, 1998). The two varieties, especially KM 94, are now widely grown, covering an area of about 60 000 ha in 1997/98 (Hoang Kim et al., 1999). Profit comparisons between KM 60 and HL20 in Dong Nai (Table 9) in 1995 showed that KM60 gave a profit of 7.71 million dong/ha9, while HL20 only gave 4.19 million dong/ha (Ao Van Thinh, 1997).

In South Viet Nam the new cultivars have gained a large acreage, already generating additional economic benefits in the order of US$5 million shared by the processors, production organizers and small farmers, according to their size of operation (Figure 10). In North Viet Nam, the total economic scale is much smaller, yet, new cultivars are spreading thin and wide. Here the additional cassava production is converted mainly into additional pig sales per family. This appears to be the most equitable contribution of crop breeding. Cassava, with the immediate possibility of yield increases, will play an increasingly important role as an income generator to upland farmers in Viet Nam (Kawano, 1999). Advanced farmers, who obtained good yields and high profits by growing improved cassava varieties, became models for other cassava growers, resulting in the expansion of new varieties. In Tay Ninh province, for example, before 1990, Gon, H34 and Binh Duong varieties occupied 100% of the production area.

9US$l = 11 000dong

Table 8. Cultivar distribution in representative cassava growing regions in Viet Nam (% in each region), 1991.

(Local name)
Northern Mountain RegionRed River DeltaNorth Central CoastSouth Central CoastCentral HighlandSouth-eastern Region
Mi Xanh (Vinh Phu)
Mi Trang16.092.727.5000
Ha Bac1.102.5000
Gon (Mi Do)
H 34009.628.277.06.8
HL 200000033.6
HL 2300036.308.2
HL 240000.721.030.9

Source: Tran Ngoc Ngoan et al., 1995

The total cassava area was 3 350 ha with an average yield of 10.8 t/ha and production of 36 000 tonnes in 1990. However, in 1998, new high-yielding cassava varieties rapidly replaced the local ones. The new varieties KM 94, KM 60, SM 937-26 and KM 95 soon covered 80–90% of the total cassava area (about 15 000 ha) of Tay Ninh with an average yield of 20.5 t/ha (Pham Thi La, 1999). Economic analyses (Table 10) showed that KM 60 could give a profit of 4.71 million dong/ha (Tran Vien Thong, 1997).

Root crops germplasm collection and maintenance were also considered. Project KN 01–07 (1991–1995), with cooperation and support from IDRC, CIAT and CIP, surveyed and explored 270 sites in 43 provinces of Viet Nam. 1 208 root crops accessions were collected, including 12 local cassava varieties. In vitro maintenance techniques were also established. Some root crops germplasm is being maintained in vitro, including 86 cassava accessions (Truong Van Ho, 1997).

5.2 Agronomic research

The National Root Crops Program cooperated with CIAT in conducting a survey on cassava cultural techniques at the national level, interviewing 1076 farmers households in 20 provinces of six ecological regions during 1991–1992. The survey provided a general picture of cassava cultural techniques in Viet Nam (Pham Van Bien et al., 1996; Hoang Kim and PhamVanBien, 1996).

Figure 9

Figure 9. Change in the mean of breeding population (all entry mean in yield trials) in fresh root yield and root dry matter content at Hung Loc Research Center, South Viet Nam. Source: Kawano, 1999.

Table 9. Comparison of on-farm earnings between old and new cassava cultivars planted in Dong Nai province, 1995/96.

Economic item or indicatorUnitHL 20 (old cultivar)KM 60 (new cultivar)
Unit price
('000 d)
Total cost
('000 d/ha)
AmountUnit price
('000 d)
Total cost
('000 d/ha)
Land taxha12502501250250
Land preparationha15005001500500
Planting materiallong stake15000.1522515000.5750
Labour for plantingmanday715105715105
Fertilizer - Ureakg1002.82801602.8448
- Phosphorus
- Potassium
Total production cost   2 560  3 545
Total income (sale)t154506 7502545011 250
Net profit   4 190  7 705
Figure 10

Figure 10. Additional economic effects generated by the adoption of new cassava cultivars in South Viet Nam from 1992 to 1996. Source: Kawano, 1999

Table 10. Cost analysis for a new cassava production scheme using cultivar KM 60 in Tay Ninh province in 1995, assuming the yield of 20 t/ha fresh roots.

(per ha)
Unit price
('000 d)
Total cost or income
('000 d/ha)
1. Total cost   3 687
 Other land preparation 1150150
 Planting stakesbundle5010500
 Chemical   72
 Ammonium Sulfatebag375225
 Potassium Chloridebag390270
 Farm yard manuret250100
2. Income   8 400
 Root harvestt203006 000
 Planting stakesbundle40062400
3. Net profit   4713

US$1 = 11.000 d;

Source: Ao Van Thinh, 1996 (Dong Nai Agric. Office)

The Agricultural Planning Institute, studying the characteristics of cassava growing lands, showed that: 1) the Southeastern Region has various kinds of soils with the best fertility compared with other mountainous and hilly regions; 2) the Southeastern Region has great potential for cassava production; and 3) present cassava growing soils have very low fertility in the Southeastern Region (Pham Quang Khanh, 1997).

In recent years the National Root and Tuber Crops Program of Viet Nam, with the cooperation and assistance of CIAT, has drawn up a plan for strengthening the research and development capacity, with the objective of improving cassava production in Viet Nam. In the area of cassava agronomy (Nguyen Huu Hy et al, 1998), the program has obtained the following results:

5.3 Farmer participatory research in soil management and varietal dissemination

Farmer Participatory Research (FPR) in Viet Nam has been carried out since 1994 in collaboration with CIAT, with the objective of improving the adoption of soil conservation practices in cassava fields (Nguyen The Dang et al, 1998).Three districts were selected (two villages in Pho Yen district, Bac Thai province, one in Thanh Hoa district, Vinh Phu province and one in Luong Son district of Hoa Binh province) as pilot sites for implementing the FPR methodology.

In 1994 by using RRA and PRA methods in conducting diagnostic surveys, the main limiting factors in cassava production have been identified: lack of suitable planting methods and materials for soil erosion control, lack of knowledge about balanced fertilizer application and about high-yielding varieties. Therefore, demonstration plots with 17 treatments involving NPK applications and various methods to control soil erosion were established at the Agro-forestry College in Thai Nguyen, Thai Nguyen. Farmers' field days were held to show the demonstration plots to farmers and extensionists from the two selected districts in mid Nov, 1994. Based on the results and discussion, seven treatments were identified by farmers as promising practices; they also discussed how to test these in simple FPR trials in their own fields.

In 1995, 35 farmers of two villages in PhoYen district participated in the research conducted on their own fields. At time of harvest, a farmers' field day was held in Thanh Hoa and Pho Yen districts in mid November 1995. Farmers and researchers joined in the harvest and the discussion of the results. Some best treatments were identified. The treatments of cassava intercropped with peanut and vetiver grass grown as contour hedgerows, combined with balanced NPK application, was considered as the most promising practice at both pilot sites, where soil losses were reduced by 20–40% compared to the check plot of cassava grown in monoculture and without hedgerows. In Pho Yen district cassava yields remained about the same, while net income increased 9–36%. In Thanh Hoa cassava yields increased about 9% compared to the check plot, while net income increased by 23%. In this location cassava intercropped with peanut increased net income from 131 to 273% over cassava monoculture. Farmers who tested new promising clones considered KM 60 and CM 4995–7 as the most suitable for their conditions; these increased yields from 1.66 to 4.07 t/ha over the check variety Vinh Phu. These initial results are encouraging more and more farmers to participate in the FPR trials. In 1996, the number of farmers participating increased and some of them can conduct now the trials by themselves.

The University of Agriculture and Forestry of Ho Chi Minh city collaborated with HARC and CIAT in the study of application of new cassava varieties and new cultural techniques suitable for the Southeastern Region. The results show that intercropping peanut with cassava gave higher economic benefits than cassava monoculture (Nguyen Thi Sam et al., 1997). On-farm trials on balanced fertilizer applications, herbicide applications and the production of cassava on sloping lands are continuing (Nguyen Huu Hybrid, 1997).

Cassava extension activities concerning the dissemination of new varieties, the establishment of high profit models for cassava production and the maintenance of soil fertility, were conducted in many provinces, particularly Tay Ninh (Tran Van Cau, 1997), Dong Nai (Tran Nhu Do, 1998; Nguyen Viet Bo, 1997), Quang Ngai (Vo Thanh Thuy and Nguyen Van Lai, 1997), Daklak (Y Ghinie, 1997), Quang Nam Da Nang (Le Muon and Pham Dinh Thanh, 1997), Binh Dinh (Bui Van Nhieu and Do Tan Tien, 1997), Khanh Hoa (Dinh Thi Duc, 1997) and Binh Thuan (Le Thanh Diep and Tran Dinh Khoa, 1997).

5.4 Root storage and processing

We have seen above that there are basically three types of cassava processing systems in Viet Nam (Quach Nghiem, 1996): 1) family-scale or on-site processing in cassava growing areas; 2) communal-scale or “village enterprise” processing; and 3) industrial-scale processing. During the last ten years, small-scale cassava processing has developed well. The experiences obtained have shown that in those villages where farmers are involved in agro-product processing, the income is much higher than in villages where farmers deal only with cassava production. The report presents some recently developed processing technologies appropriate for rural conditions, such as fresh cassava processing into starch without the necessity of drying cassava after harvest, HCN- free pellets of fermented animal feed, maltose, noodles and chips. These technologies have been effectively used at the village level.

A survey on the cassava production, processing and marketing in the Southeastern Region was conducted by IAS in 1992 (Tran The Thong et al., 1992). The main products of cassava processing at the village level in South Viet Nam were cassava starch, cassava strips (bot khoai), cassava pearls, noodles and cakes. In addition, cassava was an important component of ingredients used for making candies, many kinds of foods and instant noodles (Nguyen Dang Mai et al., 1992). HARC, in collaboration with the Institute of Post Harvest Technology, successfully conducted a “Study on the utilization of local strains of Aspergillus orizae for production of sauce “TUONG” from sweet potato, cassava and soybean in south Viet Nam” (Nguyen Dang Mai et al., 1994).

The recently established cassava processing industry is playing an important role in the improvement of cassava production.

5.5 Economic and marketing research

A study on cassava economics and markets in Viet Nam was conducted during 1991–1992 (Pham Thanh Binh et al., 1996). Another study on the present situation of cassava starch and its potential was also published (Dang Thanh Ha et al., 1996). Other information on technical and economic aspects of cassava production and processing in the principal present and future consuming regions have been analyzed (Ao Van Thinh,1997; Tran Vien Thong, 1997; Doan Huu Lich,1997; Tran Ngoc Quang, 1997; Nguyen Thi Bong, 1997).


6.1 Establishment of a National cassava research and extension network

A chart on cassava research and extension activities is shown in Figure 11. It is essential to build up a national cassava research and extension network, including advanced cassava farmers, researchers, extensionists, managers of cassava research and development projects, cassava trade and processing companies. The network was established in 1991 and workshops have been organized annually at HARC. Objectives, responsibilities, subjects and methods are discussed and adapted to Vietnamese production conditions in the process of operation and development (Hoang Kim et al., 1995).

6.2 Establishment of demonstration fields and FPR

On-farm research and transfer of technologies were particularly emphasized: HARC is conducting three related research topics, including breeding, cultivation techniques and transfer of technologies (Figure 12). Cropping systems research in IRRI (Zandstra et al., 1981; Carangal, 1990), agro-ecosystem analysis (Conway, 1986), and farmer participatory research (Howeler, 1997) methodologies were used in cassava research and development programs.

6.3 Ten mutual link-up extension activities 10Ts)

The extension methodology used by the Institute of Agricultural Science of South Viet Nam (IAS) are summarized in the following 10 letters T (in Vietnamese)

(1)Thu nghiemTrials
(2)Trinh dienDemonstrations
(3)Tap huanTraining
(4)Trao doiExchange
(5)Tham viengFarmer tours
(6)Tham quan, hoi nghi dau boFarmer field days
(7)Thong tin tuyen truyenInformation, propaganda
(8)Thi duaCompetition
(9)Tong ket khen thuongRecognition, praise and reward
(10)Thanh lap mang luoi nguoi nong dan gioiEstablish good farmers' network

Provinces'000 ha (1991)Figure 11
1.Ha Noi-
2.Ho Chi Minh0.7
3.Hai Phong(0.3)
4.Ha Giang(5.5)
5.Tuyen Quang(7.0)
6.Cao Bang1.9
7.Lang Son3.8
8.Lai Chau7.5
9.Lao Cai4.5
10.Yen Bai10.5
11.Bac Thai4.9
12.Son La12.7
13.Vinh Phu12.5
14.Ha Bac8.1
15.Quang Ninh(3.3)
16.Ha Tay4.3
17.Hoa Binh8.7
18.Hai Hung(0.3)
19.Thai Binh(0.1)
20.Nam Ha(0.5)
21.Ninh Hoa(1.6)
22.Thanh Hoa14.4
23.Nghe An11.8
24.Ha Tinh2.8
25.Quang Binh4.0
26.Quang Tri3.5
27.Thua Thien-Hue6.2
28.Quang Nam-Da Nang17.5
29.Quang Ngai12.0
30.Binh Dinh10.9
31.Phu Yen4.7
32.Khanh Hoa8.2
33.Ninh Thuan(2.8)
34.Binh Thuan(3.5)
35.Kon Tum(6.0)
36.Gia Lai(8.0)
37.Dac Lac4.8
38.Lam Dong2.1
39.Song Be4.9
40.Tay Ninh3.3
41.Dong Nai(12.0)
42.Long An(2.5)
43.Dong Thap(0.1)
44.An Giang(0.9)
45.Tien Giang(0.8)
46.Ben Tre(0.7)
47.Vinh Long(1.0)
48.Tra Vinh(2.0)
49.Can Tho(0.3)
50.Soc Trang(0.2)
51.Kien Giang(2.3)
52.Minh Hai(0.9)
53.Ba Ria-Vung Tau(3.0)

Figure 11. The research and technology transfer network for current cassava production in Viet Nam.

Figure 12

Figure 12. Strategy for on-farm research and transfer of technology for cassava production in the Southeastern Region: A case study conducted by Hung Loc Agricultural Research Center.

6.4 Six essential conditions (6Ms) for a successful cassava R&D program


7.1 Direction for the future

In the assessment and planning of agricultural and rural development of Viet Nam up to the year 2000, food production will still be the most important and strongest production branch. The Vietnamese government has chosen a strategy of increasing rice and maize production, and at the same time of attaching great importance to the production of cassava, sweet potato and Irish potatoes in those areas and in those seasons having appropriate conditions for their development (Nguyen Cong Tan, 1993). The cassava planting area in Viet Nam during the coming years will not be increased, but will remain within the range of 200 000 to 300 000 ha; however, cassava yields will increase by the adoption of new cassava varieties and more intensive cultural practices. On-farm research and transfer of technology for cassava production are key factors for cassava development. They are an important bridge linking science with production. Another priority problem is to link small cassava farmers and processors to regional and international growth markets of cassava starch-based products by expanding existing cassava markets, and by process and product analyses in Southeast Asia. This will serve as a basis to develop an action plan for the integrated R&D of cassava production, processing and marketing.

7.2 Recommendations

Strengthening cooperation between the Viet Nam Cassava Program and IFAD/CIAT, not only in cassava varietal improvement but also in the area of on-farm research and transfer of technology (varietal dissemination; fertilizer supply; intercropping/or rotation of grain legumes and cassava; erosion control; chemical weed control, etc.)

Development and value-adding of cassava products for rural small-scale processors in Viet Nam.

Obtaining financial support from the International Fund for Agricultural Development (IFAD), cassava processing and trade companies (Vedan, etc) and International Agricultural Research Organizations (CIAT, ACIAR), Viet Nam Government and non-governmental organizations.


This review of “Status of Cassava in Viet Nam: Implication for Future Research and Development” was completed with friendly and helpful cooperation from many scientific institutions and individuals in Viet Nam.

The authors wish to thank the personnel from all those organizations who cooperated in the compilation of this report. Special thanks are extended to Dr. Kazuo Kawano, Dr. Guy Henry (CIAT scientists), Dr. Tran Ngoc Ngoan, Dr. Nguyen The Dang (Thai Nguyen University, Agro-Forestry College), Dr. Pham Thanh Binh, Dr. Dang Thanh Ha (University of Agriculture and Forestry in Ho Chi Minh City). The authors are also grateful to Mr. Nguyen Thanh Binh for his editorial and technical advise. Appreciation is also extended to Mr. Abdou Ciss and Dr. Mattia Prayer Galletti and IFAD who gave the author the opportunity to contribute towards a closer liaison between IFAD and Viet Nam in cassava research.


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