| Rice disease resistance is the result of interaction between host and pathogen. The knowledge of
differentiation of pathogenic strains is the prerequisite for disease resistance evaluation and its application. In this study,
the rice cultivars including JinGang30, IR24, IRBB21, IRBB14, IRBB5, IRBB4 and Wushansimiao were used as the host
differenials. The pathogenicity of 72 bacterial leaf streak strains from Guangdong area had been tested. Some of main varieties
from Guangdong were selected for their resistance evaluation with the predominant strain of bacterial leaf streak pathogen. The
results showed that the pathogenicity of bacterial streak strains from Guangdong area was obviously diversity. The tested strains
could be classified into 19 pathotypes, among which the predomni ant pathotypes were C18（ SSSSRSS）and C5（SRRRRRS）,
accounting for 25% and 23.61% respectively. The strong virulent strains which accounted for 27.78% of the tested strains,
including C17（SSSRSSS）, C18（SSSSRSS）, C19（SSSSSSS）, were mainly distributed in Guangzhou, Huizhou,
Yangchun, Maoming, Xinhui, Guangning, Leizhou area. Almost of eighteen main varieties from Guangdong were susceptible to
the tested strains, except that the Xinyinzhan variety show medium susceptible to the predominant strain of C18. （SSSSRSS）. |
