Resistance evaluation of rice varieties against Nigrospora oryzae（Berk.et Br.）Petch

The resistances of 77 rice varieties against Nigrospora oryzae（Berk.et Br.）Petch were evaluated in disease nursery in Baisha，Yangjiang，Guangdong. The disease index was used for evaluating the disease resistance of the tested entries. The results showed that there was significant difference of resistance against N. oryzae among different varieties. There were 0，1，7，17，15 and 37 varieties showed high resistance（HR）， resistance（R），moderately resistance（MR），moderately susceptivity（MS），susceptivity（S）and high susceptivity（HS）respectively. Some of the tested varieties showed more resistance with the disease index from 20 to 30，such as Wuyuezhan NO.2，Yueaozhan，Xiangyinong NO.1，Zhangyou 736，H Liangyouyezhan，Xinliangyou 117. However，some of the tested entries showed more susceptivity with the disease index over 50，such as Pengdao NO.2.，Zhanhuangzhan，Helisimiao，Yuebiao NO.5，Chanzengzhan，Zhenyou 21，Meiyoufengzhan， IIyou 916. The varietiy Pengdao NO.2 showed high susceptivity with the disease index of 100，and its whole plant were damaged seriously by N. oryzae.