Evaluation of resistance to rice blast of japonica rice landrace resources in Yunnan

【Objective】Yunnan japonica rice blast resistant germplasm resources were obtained through identification and screening. Furthermore，the distribution of rice blast resistance genes in Yunnan japonica local rice resources were studied，which provided reference for rational utilization and distribution of rice blast resistance germplasm resources. 【Method】The blast resistance of Yunnan japonica local rice resources was identified by natural identification in nursery and artificial inoculation. Rice blast resistance of 150 Yunnan japonica local rice resources was identified. Nine cloned genes（Pid4，Pi25，Pi35，Pi36，Pikm，Pigm，Pi37，Pi56，Pi33）and two localized genes（Pi27，Pi23）were used to detect the genotypes of the tested rice germplasms to determine the distribution of resistance genes in rice blast resistance materials.【Result】A total of 45 rice materials resistant to rice blast（leaf blast or panicle neck blast）were identified from 150 rice materials. The numbers of resistant materials carrying resistance genes Pi25，Pi23，Pikm，Pi35，Pi36，Pi33，Pi27， Pi37，Pid4 and Pigm were 34（75.6%），25（55.6%），25（55.6%），22（48.9%），14（31.1%），14（31.1%），12（26.7%）， 10（22.2%），6（13.3%）and 5（11.1%）. No material containing Pi56 was detected. The number of resistance genes in 45 resistant materials ranged from 1 to 7，and most of them contained 3 to 5 resistance genes，including 13 materials carr-ying three resistance genes（28.9%），8 materials carrying 4 resistance genes（17.8%）and 11 materials carrying 5 resistance genes（24.4%）. Heikegu with strong disease resistance carried 6 resistance genes（Pi25，Pi35，Pi36，Pikm，Pi37 and Pi33），and Guangkehuanuo carried 5 resistance genes（Pi35，Pi36，Pikm，Pi37 and Pi33）.【Conclusion】In this study，45 japonica rice blast resistant materials in Yunnan were obtained. And 2 materials with resistance to leaf blast and neck blast were identified as Heikegu and Guangkehuanuo during the whole growth period they the gene combination of Pi35-Pi36-Pikm-Pi37-Pi33. This study can provide resistance source materials for molecular breeding and gene mapping of resistance to rice blast.