ABSTRAKPenelitian dilakukan untuk membedakan virulensi isolat Rice tungro virus (RTV) dari beberapa daerah endemis penyakit tungro di Indonesia berdasarkan reaksinya pada tanaman inang diferensial. Delapan isolat RTV dikumpulkan dari beberapa daerah endemis penyakit tungro di Indonesia, yaitu Bali (Denpasar), Kalimantan Selatan (Tanah Laut), Sulawesi Selatan (Lanrang), Jawa Barat (Subang dan Bogor), Jawa Tengah (Solo), Jawa Timur (Jember), dan Nusa Tenggara Barat (Mataram). Semua isolat dipelihara pada kultivar padi TN1 di rumah kaca melalui penularan serangga vektor Nephotettix virescens, selanjutnya masing-masing isolat ditularkan pada kultivar padi diferensial FK135 dan TN1. Empat minggu setelah inokulasi pada kultivar padi diferensial diamati gejala yang muncul dan infektifitas masing-masing isolat RTV. Tingkat virulensi isolat RTV dari beberapa daerah endemis penyakit tungro di Indonesia dapat dikelompokkan menjadi 3 tingkat. Virulensi paling tinggi ialah isolat RTV dari Jawa Barat; tingkat virulensi moderat ialah isolat RTV dari Jawa Timur, Kalimantan Selatan, Sulawesi Selatan dan Nusa Tenggara Barat; tingkat virulensi rendah ditunjukkan oleh isolat RTV dari Bali dan Jawa Tengah.Kata kunci: kultivar diferensial, Nephotettix virescens, padi, penyakit tungro
ABSTRACTThe research was conducted to distinguish the virulence of Rice tungro virus (RTV) isolates from several tungro disease endemic areas in Indonesia based on their response in differential cultivars of rice. Eight isolates of RTV were collected from several tungro endemic regions in Indonesia i.e. Bali (Denpasar), South Kalimantan (Tanah Laut), South Sulawesi (Lanrang), West Java (Subang and Bogor), Central Java (Solo), East Java (Jember), and West Nusa Tenggara (Mataram). The isolates were maintained on TN1 rice cultivar in greenhouse by successive transfers via Nephotettix virescens. Each isolate was subsequently passed on to FK135 and TN1 rice cultivars. Four week after inoculation, plants responses were observed to compare their symptom and infectivity on the differential cultivars. The results showed that the level of virulence of RTV isolate from tungro disease endemic areas in Indonesia can be classified into 3 levels. The highest virulence were RTV isolates from West Jawa, the moderate level of virulence were RTV isolates from East Java, South Kalimantan, South Sulawesi, and West Nusa Tenggara, the low level of virulence were RTV isolates from Bali and Central Java.