Preliminary Study On The Rosa Rootstock Resistance To Crown Gall

Crown gall disease caused by Agrobacterium spp. is important disease that decreases rose production severely. Propagation of rose is carried out in grafting generally. Using resistant rootstock is a good method for the control of this disease.Trial rootstock materials are cathayensis (Rose multiflora var. cathyensis), R. multiflora 'Inermis No.3', R. multiflora 'Inermis No.4', R. multiflora 'Inermis No.11'and their crossed progenes. needle-prick inoculation was used to evalute the ability of resistance to growngall. In vivo and in vitro tested methods had been applied in this study.11 strains of Agrobacterium spp. were isolated from 4 rose cultivars tumor tissue. By analysis of colony morphometries and sunflower inoculation, 4 stiains were identificated as Agrobacterium tumefaciens. They were used as the source of rose inoculation.Cathayensis is used in north China widely. In vivo method results indicate that No.3 (R. multiflora 'Inermis No.3') has stronger resistence to crown gall than cathayensis (R. multiflora var. cathyensis), and can be used as resistant disease rootstock in production.The traditional in vivo method to test resistance of rootstocks to grown gall disease is affected by enviromental conditions. In this study, In vitro test method was studied additionally. The results indicated that cathayensis tumors formed 7 days after inoculation, while in vivo test was several weeks. So in vivo method maybe used as a feasible method for testing resistance to crown gall disease.