Resistance Durability Of Several Rice Cultivars Against Rice Tungro Disease In South Sulawesi, Indonesia

Tungro disease is one of the main obstacles to rice production in South and Southeast Asia. The cultivation of green leafhopper resistant rice and tungro virus-resistant rice is one of the ways to prevent tungro disease and has been successfully used to control the disease in the tropics. However, some of these varieties have been reported to have lost their resistance due to the adaptation of resistance in green leafhopper population against tungro resistant varieties. Until now, rice varieties that are resistant to green leafhoppers and rice tungro virus which are still frequently used by farmers in South Sulawesi are IR 64, Ciliwung, Inpari 9 Elo, and Inpari 7 Lanrang varieties. Thus, it is necessary to evaluate the durability of these varieties, whether they are still resistant to tungro disease or not. Variety resistance was evaluated by calculating the reduction in plant height (%), percentage of rice tungro virus infection (%) and detection of the presence of rice tungro virus using a PCR analysis for RTBV and an RT-PCR for RTSV after being inoculated with tungro virus isolates from South Sulawesi. Results showed that all resistant varieties were infected by tungro bacilliform virus (RTBV): 100, 100, 80, and 80% infections on IR-46, Ciliwung, IR-64, and IR- 66, respectively. For the RTV-resistant cultivars, only Inpari 9 Elo and Inpari 7 Lanrang were not infected by rice tungro spherical virus (RTSV). Therefore, it is concluded that to prevent transmission of the tungro virus, Inpari 9 Elo and Inpari 7 Lanrang can still be recommended for planting in South Sulawesi.