Komposisi dan Dominasi Patotipe Xanthomonas oryzae pv. oryzae Penyebab Hawar Daun Bakteri pada Tanaman Padi dengan Pola Tanam Tidak Serempak

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae ( Xoo ) is an important disease in rice crop. The objectives of this research was to determine the dynamic composition and the domination of the Xoo pathotypes in rice crop under unsynchronous planting pattern. The research was carried out in Klaten Regency, Central Java Province, during Wet Season (WS) of 2014/2015 and Dry Season (DS) of 2015. The research consisted of three steps, namely: observation and sampling of the diseased plants from the field, isolation of the pathogen in the laboratory, and pathotype identification in the greenhouse. Observations and samplings of the diseased plants from each growing season were conducted at three planting times, i.e.: early planting (I), mid planting (II), and late planting (III). The observation of BLB disease in the field showed that disease severity during WS 2014/2015 was higher than that during DS of 2015. The Xoo pathotype composition during wet season and dry season consisted of pathotype III, IV, and VIII with varying degrees of dominancy among the planting periods in the season, as well as among seasons, and between observation locations. The composition of Xoo pathotypes was dominated by pathotype IV during the early and mid season planting periods of the wet season, whereas at the end of planting period was dominated by pathotype III. Xoo composition during early, mid, and late season planting periods of the dry season was dominated by pathotype III. The recommendation for BLB disease control in an unsynchronous cropping pattern at early and mid season planting periods of the wet season is by growing varieties resistant to Xoo pathotype IV, while in late planting period it is suggested to grow varieties resistant to Xoo pathotype III and VIII. The BLB disease control in areas practicing early, mid, and late planting periods during the dry season is suggested to grow varieties resistant to Xoo pathotype III or VIII.