Screening of Indonesian rice cultivars against bacterial leaf blight disease under acidic soil condition

Abstract Marginal lands, which often have poor soil, are largerlyfound in North Sumatra, Indonesia. Acidic soil, one of margial lands, become an obstacle for agiculture including rice growing. Additionally, bacterial leaf blight disease which is caused by Xanthomonas oryzae pv oryzae, is also the main problem for rice production in Indonesia and worldwide. This study was aimed to screen rice cultivars that were tolerant to acidic soils and showed resistance to bacterial leaf blight (X. oryzae pv. oryzae).This research was conducted at the Screenhouse in Faculty of Agriculture, Universitas Sumatera Utara from July to November 2020. This experiment was designedas factorial Randomized Block Design (RBD) by 3 factors, i.e. Factor 1:rice cultivars (Inpari 30, Inpara 5, Inpago 9 and InpagoUnsoed 1); Factor 2: soil pH (control (pH 6.8) and pH 4.0); Factor 3:isolate of X.oryzae pv oryzae (Xoo 1) with three replications. The results showed that all cultivars grown in acidic soil were susceptible to bacterial leaf blight diseases, while all cultivars grown in control soil pH were moderately susceptible. Disease incidence for all cultivars were 100% starting from the fifth week after planting. Plant growth in acidic soil was affected more severely than that of on neutral soil, while the highest disease severity was 75 % (Inpari 30).