Research On Resistance Identification Of Tobacco To Wildfire And RAPD Marker Of The Resistant Gene And Its Application In Marker-assisted Selection

Tobacco wildfire, caused by Pseudomonas syringae pv. tabaci, hasbecome a serious disease in tobacco production. When the climate is sutiablefor its occurrence, it will break out and badly destroy the tobacco cultivation.There are several measures including planting the resistant cultivars,appplying good agricultural practice and chemical control to control thedisease, but application of resistant varieties is the most cheap and effectiveone. Molecular marker-assisted selection can shorten the process to breed theresistant varieties because it avoids some troublesome procedures such asinoculation and promotes the accuracy of selection. The study mainly relatedto four parts. (1)Establishing a good inoculation method to identify theresistance of tobacco germplasm in greenhouse. (2)Testing the hereditaryrule of the wildfire resistant gene from Nicotiana longiflora. (3)EstablishingF2 population of the cross of Speight G-140 and Ky14 and using bulkedsegregant analysis to seek RAPD makers linked to the wildfire resistant gene.(4)Applying the RAPD makers to select the resistant plants in BC1population of Speight G-140 and Ky14 and to verify the markers further. Themain results are as follows.(1)A good inoculation method in greenhouse was developed, whichwas first slightly pricking the leaf with the needle of an injector, then injectingthe tiny wound with the injector without needle. Stabbing the leaf surfacemade inoculation easy, and injecting the tiny wound with an injector withoutneedle easily controlled the amount of bacterial suspension and made itconvenient to observe the diameter of disease spots. Keeping optimum...