Komposisi Dan Penyebaran Patotipe Xanthomonas Oryzae Pv. Oryzae, Penyebab Penyakit Hawar Daun Bakteri Padi Di Jawa Timur

Abstract

The pathotype composition and distribution of Xanthomonas oryzae pv. oryzae (Xoo) in central of rice production in East Java. An experiment to study the pathotype composition and distribution of Xanthomonas oryzae pv. oryzae (Xoo) in central of rice production in East Java was conducted at the planting season of 2010. Three steps trial was conducted such as removed of leaves infected by bacterial leaf blight (BLB, isolation of Xoo in a laboratory, and tested pathotype in screen house. Rice leaves showing typical bacterial leaf blight symptom were collected from various farmers rice field. The samples were detached and put into the paper envelope, and then it taken in the laboratory for isolation process of Xoo. Isolation of Xoo was done in the Laboratory of Pythopathology, Indonesian Centre for Rice Research, Sukamandi. Pathotype identifications were done by inoculating the isolates of Xoo on differential varieties in the screen field ICRR in Sukamandi at wet season (WS) 2010. Resistance reaction was identified using the criteria of the disease severity. Disease severity ≥ 11% was considered resistant (R) and it >12% was considered susceptible (S). The result showed that leaves infected by BLB were obtained among 131 and it were collected 126 isolates of Xoo. Identification of pathotype indicated that in East Java, it were obtained 30 isolates (23.8% pathotype III), 43 isolates (34.1% ) pathotype IV, and 53 isolates (42.1%) pathotype VIII. Penelitian untuk mengetahui komposisi dan sebaran kelompok patotipe bakteri Xanthomonas oryzae pv. oryzae (Xoo) penyebab penyakit hawar daun bakteri (HDB) di beberapa daerah produksi padi di Jawa Timur telah dilaksanakan pada musim tanam 2010. Penelitian meliputi tiga tahap kegiatan, yaitu pengambilan sampel daun sakit HDB dilaksanakan dengan metode survei, isolasi bakteri Xoo di laboratorium, dan pengujian patotipe bakteri Xoo di rumah kaca. Daun padi bergejala HDB yang dikoleksi dari lapangan dimasukkan ke dalam amplop kertas kemudian dibawa ke laboratorium untuk keperluan isolasi bakteri Xoo. Isolasi bakteri Xoo dilakukan di laboratorium dan inokulasi bakteri Xoo pada tanaman padi diferensial dilakukan di screen field BB Padi. Isolasi bakteri Xoo menggunakan metode pencucian. Pengujian patotipe dilaksanakan dengan menginokulasikan isolat Xoo pada 5 varietas diferensial di rumah kaca dengan metode gunting. Reaksi ketahanan varietas diferensial dikelompokkan berdasarkan keparahan penyakit. Varietas tergolong tahan (T) bila keparahan penyakit kurang atau sama dengan 11%, tergolong rentan (R) bila keparahan lebih dari 12%. Pengelompokan patotipe berdasar pada nilai interaksi antara varietas diferensial dengan virulensi bakteri Xoo. Hasil pengumpulan daun sakit HDB diperoleh sebanyak 131 sampel. Hasil isolasi bakteri Xoo dari sampel tersebut diperoleh sebanyak 126 isolat bakteri Xoo. Hasil pengujian patotipe terhadap varietas diferensial dari isolat bakteri Xoo yang diperoleh menunjukkan sebanyak 30 isolat (23,8%) tergolong patotipe III, 43 isolat (34,1%) patotipe IV, dan 53 isolat (42,1%) patotipe VIII