Evaluation of resistance to bacterial canker disease of ‘Jinfeng’ kiwifruit seed offspring

<bold>Objective</bold> Bacterial canker is a serious disease of kiwifruit around the world.Screening resistant germplasm resources and improving disease resistance of kiwifruit are important means to control the spread of bacterial canker disease.‘Jinfeng’ kiwifruit is an excellent local cultivar bred by our research group.The resistance to bacterial canker disease of ‘Jinfeng’ kiwifruit seed offspring was evaluated and this can lay the material foundation for selecting resistant germplasm and improving varieties. <bold>Method</bold> The 171 seed offspring of ‘Jinfeng’ kiwifruit were used as materials.The resistance was evaluated and further verified by the methods of artificial inoculation of canker bacteria in isolated branches and leaf disc in vitro.11 seed offspring with significant resistance differences were determined resistance-related physiological and biochemical indices. <bold>Result</bold> Correlation analysis showed that the branch inoculation method was positively correlated with the leaf disc method.Based on the length of branch disease spots and the proportion of leaf disc disease spots，171 samples can be divided into four levels：disease resistance，disease tolerance，disease sensitivity and high sensitivity，among which 49 samples were disease resistance resources，62 samples were disease tolerance resources，49 samples were disease sensitivity resources and 11 samples were disease high sensitivity resources.From them，11 seed offspring with resistance differences were selected and further determined by physiological and biochemical indicators，and found that the total phenol，soluble sugar and lignin content in the leaf physiological indexes showed significantly positive correlations with the individual resistance. <bold>Conclusion</bold> The results of resistance evaluation in isolated branches and leaf disc method were significantly correlated，and the determination of leaf physiological indicators were significantly correlated with the results of resistance identification，which confirmed the manual inoculation method of isolated branches and isolated leaf discs is reliable.Three physiological indicators in leaves can be used as a rapid identification method of resistant germplasm.The selected disease-resistant germplasm laid the material foundation for bacterial canker disease breeding of kiwifruit.