水稻近等基因系对白叶枯病、条斑病抗性的比较研究

 研究了水稻近等基因系对白叶枯病菌不同致病型12个菌株和20个细条病菌株的抗性差异及其对两种病原菌致病力分化的鉴别力。结果表明含xa－5，Xa－7，xa－13，Xa－17和Xa－21等5个抗性基因的品种（系）对绝大多数白叶枯病菌株表现为广谱高抗，其中xa－5，Xa－17抗性基因品种兼抗细条病，但携带xa－13，Xa－21基因的抗性基因品系则感细条病。进一步表明水稻对细条病和白叶枯病的抗性是受不同的抗性基因控制的。IRBB3，IRBB4，IRBB5，IRBB13，IRBB21和阿苏稔(Xa－17)，丰锦(Xa－18)等7个单基因品种对我国的白叶枯病菌致病型具有鉴别力，划分为5个小种。依据20个菌株在15个近等基因系上的致病力差异将水稻细条病菌株分为12个致病型，经聚类分析可划分为6个组。结果进一步表明我国的水稻细条病菌株致病性分化明显。

Study on Resistance of Rice Near-iso-lines (NILs) to Bacterial Blight and Leaf Streak of Rice

The different reaction pattern of a set NILs to strains representing different pathotypes of X.o. pv. oryzae (Xoo) and 20 strains of X.o. pv. oryzicola (Xooi). The results showed that rice NILs with xa-5,Xa-7,xa-13,Xa-17 and Xa-21 were higher resistant to almost tested pathotypes of Xoo, in which those with xa-5,Xa-17 were also high resistant to most strains of Xooi , But the others were susceptible to several strains of Xooi. Revealing different resistant mechanism among the two pathogens and rice NILS. Based on this study, seven NILs carrying Xa-3,Xa-4,xa-5,xa-13,Xa-17,Xa-18 and Xa-21,respectively were selected as differentials could divided Chinese Xoo isolates into 5 races. Twelve pathotypes(virulence phenotypes) of X.o. pv. oryzicola were identified using 15 near iso genic rice lines,each containing a single gene for resistance. The 12 pathotypes group into six clusters, these result further showed that the virulence of X.o. pv. oryzicol a strains was significantly different in China.