Evaluation Of Resistant Varieties On Kiwifruit Bacterial Canker And Cluster Analysis Of Genetic Relations By ISSR Markers

In recent years the world-wide-outbreaking of kiwifruit bacterial canker had extremely serious impact on the kiwifruit industry.41 kiwifruit varieties(strains)from Sichuan Province Natural Resources Research Institute were used as experimental material in order to know the resistance to bacterial canker in common kiwifruit varieties in Sichuan and the relationship between the resistance and genetic diversity.In this study,some investigations of field resistance and experiments of indoor resistance on kiwifruit varieties against to bacterial canker were made and then the resistance degrees were sorted.After that,the genetic diversity of 25 female kiwifruit varieties and 16 male varieties was analyzed by using inter-simple suquence repeat markers(ISSR),and the relationship between ISSR molecular markers and the resistance was established.The main results were as follows:1.In the study of field resistance survey,Spring and autumn were high-incidence seasons of kiwifruit bacterial disease,summer and winter were low-frequency seasons.The onset period,onset vatieties and onset regional were all concentrated.’Hongshi 2’、’79-3’、’04270’、’04137’ were all susceptible cultivars.2.Experiments of resistance in laboratory showed that the resistance to bacterial disease were different in varieties of kiwifruits.Relative resistance index ranged from 0.35 to 0.82.In the view of species,A.callosa var henryi,A.deliciosa,A.tetramera,A.arguta and A.polygama were more resistant.A.chinensis,A.latifolia and A.eriantha were more susceptible to disease.For varieties,All A.chinensis species were in moderately susceptible group or susceptible group except ’79-1(M)’、’SF0808(F)’、’Jinshi 1(M)’.3.Screened from 100 primers,10 primers were used for ISSR amplification.A total of 172 bands were generated,of which 172 bands were polymorphic bands(the percentage of polymorphic band,PPB=100%).The genetic similarity of female cultivars varied from 0.51 to 0.87,and the genetic similarity of male cultivars varied from 0.60 to 0.90.4.The cluster analysis showed that the females were divided into 2 major groups.Classlwas made up of Sect.Stellatae and Sect.Maculatae,Class 2was made up of ser.Lamellatae and ser.Solidae of Sect.Leiocarpae.Then,Class 1 was divided into 4 groups.Group A was A.callosa var henryi.Group B was A.eliciosa(diploid).Group C included A.eriantha.’Soreli’ and A.latifolia.Group D included the A.chinensises and the A.delicisaes.The males were divided into 3 major groups.Class 1 was made up of 14 cultivars of Sect.Stellatae.Class 2 was ’Kuilv’ and Class 3 was A.tetramera.Then,Class 1 was divided into 4 groups.Group A was.A.latifolia and A.eriantha.Group B was’Hongyang’,’Hongshi2’,’Jinshi2’.’Soreli’,’04137’,’Jinyan’ and ’Hortl6A’.Group C included ’79-1’,’Qinmei’,’Hongmei’.Group D was ’Hayward’.The test showed that A.callosa var henryi,A.deliciosa,A.tetramera,A.arguta and A.polygama were more resistant.A.chinensis,A.latifolia and A.eriantha were more susceptible to disease.which related to hereditary.Kiwifruit bacterial disease were largely-area-outbreaking in spring and autumn and the resistance was connected with inheritance.It was obvious that resistance grouping and ISSR clustering had significant correlation.The researches revealed that IS SR markers can be used as an effective means on anti-PSA-varieties in early screening of kiwifruit breeding.