丽江新团黑谷近等基因系抗稻瘟病分析

利用31个稻瘟病菌株对由国际水稻研究所育成以不具有主效抗性基因的丽江新团黑谷为轮回亲本的一套单基因近等基因系和8个抗性基因组合进行接种鉴定，结果表明，不同抗性基因的抗谱存在显著差异，其中IRBLZ-Fu(Pi-z)、IRBLZ5-CA(Pi-z-5)、IRBLZt-T(Pi-z-t)、IRBL9-W(Pi-9(t))的抗性频率分别为93%、97％、90％和96％，可初步认为Pi-z、 Pi-z-5、 Pi-z-t、Pi-9(t)为广谱抗性基因；不同抗性基因组合的抗谱均较其亲本宽，主要表现为抗性基因间的互补效应和积加效应，本研究为基因聚合培育广谱持久的抗性品种提供了理论依据。

Identification of IRBL Near-isogenic Lines for Rice Blast Resistance

To elucidate the resistance spectra of resistance genes and the feasibility of breeding the cultivar with durable and broad-spectrum resistance by integrating resistance genes,the monogenic NILs bred by IRRI with the background of LTH,a native variety in Yunnan without any major resistance gene and their eight combinations were identified by inoculating 31 Magnaporthe grisea isolates.The results indicated that the resistance spectra were remarkably different among the lines,and the resistance frequencies of IRBLZ-Fu(Pi-z),IRBLZ5-CA(Pi-z-5),IRBLZt-T(Pi-z-t),IRBL9-W(Pi-9(t)) were 93%,97%,90% and 96%,respectively,showing that the four genes Pi-z,Pi-z-5,Pi-z-t and Pi-9(t) were perceived preliminarily to be broad-spectrum resistance genes.At the same time,to avoid to the linkage,the resistance genes in different chromosomes were accumulated except for Pi-k-s and Pi-k-p.The resistance spectra of the combinations were broader than those of their parents because of complement effect and additive effect.Namely,on the one hand,the lines with single resistance gene were susceptible to some isolates,or some was susceptible,and some resistant,but the combination was resistant.On the other hand,some lines with single resistance gene and some combinations were susceptible to some isolates,but the size and the number of the lesion of the combinations were less than those of the lines with single resistance genes.Integrating several resistance genes into a cultivar would be useful for expanding resistance spectrum and durability.Pi-z,Pi-z-5,Pi-z-t and Pi-9(t) had great potential in resistance breeding,in spite of that the mechanism of their broad spectrum was not known.In addition,the resistance spectrum of the combination was broader than those of Pi-k-s and Pi-k-p.It's not clear whether the mechanism of the broader spectrum was similar or same to the relation between EDS1 and PAD4 in Arabidopsis thaliana.