Cassava varietal dissemination in Vietnam

Before 1985, Gon, H34 and Xanh Vinh Phu were the most popular cassava varieties in Vietnam. From 1986 to 1993, HL20, HL23 and HL24 were selected from the local variety collection by Hung Loc Agricultural Research Center (HARC) and were grown extensively in South Vietnam with annual areas of about 70,000 to 80,000 ha planted to these varieties. More recently (1993-1996) the Vietnam Root Crops Program in cooperation with CIAT, selected and recommended two new cassava varieties, KM60 (Rayong 60) and KM94 (MKUC 28- 77-3); these were recognized and released for production by the Ministry of Agriculture and Rural Development (MARD). The two varieties are now widely grown in an area of about 15,000 ha in 1996. The report presents the linkage between cassava research and extension activities in Vietnam. Experiences and methods of cassava varietal dissemination include ten mutual link-up activities (ten Ts). The most important one was the establishment of the Vietnam Cassava Research and Extension Network (including advanced cassava farmers, researchers, extensionists, managers of cassava research and development projects, cassava trade and processing companies), and the establishment of on-farm research and demonstration fields (Farmer Participatory Research- FPR). The Vietnam Cassava Research and Extension Network obtained good results during the period of 1993 1995. Advanced fanners who obtained high yields and high profits due to the growing of improved cassava varieties, became attractive models for other cassava growers, resulting in the expansion of new varieties. In Tay Ninh province, for example, in 1990 the cassava growing area was 3,350 ha, with an average yield of 10.8 t/ha and a total production of 36,200 tons. With the planting of new high-yielding varieties and new cultivation techniques, in 1995 the cassava growing areas had increased to 18,870 ha with an averaged yield of 20.5 t/ha and a total production of 386,900 tons. Six essential conditions for the successful cassava varietal dissemination in Vietnam include: Materials, Markets, Management, Method, Manpower and Money (six Ms). However, other problems should be taken into account: Crop competition (especially between cassava and sugarcane); soil fertility degradation and erosion; and decreasing varietal diversity