최근 벼 흰잎마름병의 레이스 분포양상 및 저항성 유전자원 검정을 위한 혼합 균주

Bacterial leaf blight(BLB) caused by Xanthomonas oryzae pv. oryzae(Xoo) is a major disease in Rice production. Even though the cultivation of resistant varieties to BLB has been considered one of the ways to control that disease, the problem of this strategy is that resistance can be broken because of new pathogen races being emerged against resistant varieties. Therefore, it is necessary to establish countermeasures to prevent breakdown of rice genetic resistance. Investigations on the distribution and discrimination of race and the first date of BLB incidence in rice fields were conducted as well as representative combinations of mixed-strains were selected for various resistant test to be used on IRBB germplasm for resistance to BLB. The first symptom of BLB spreading rapidly was founded on mid July in Jeonnam province and on early August in Jeonbuk province except for Buan where BLB observed on late July. The occurrence area was 2,345ha in 2012, 5,253 ha in 2013, and 11,677 ha in 2014, showing increasing in incidence over the year. K3 race was dominant from 2012 to 2014 and also showed increased dominance rate from 59.2% to 83.3% in 2012 and 2014, respectively. Most tested strains could infect IR24 and Milyang 23, but no strains could infect IRBB5 and IRBB7 known as resistant variety. Combination 2, 3, 5, 7, 8, and 9 showed strong infectivity on many genetic resources. IRBB 5 and IRBB 7 showed moderate resistance to Combination 12 and IRBB 5 and IRBB 21 showed moderate resistance to Combination 6 and 10.