Inheritance Of Resistance Potato Virus Y In Tobacco And Molecular Marker Inhentification

Tobacco (Nicotiana tabacum L.) is one of the most important cash crops, and tobacco potato virus Y disease, also known as vein spot disease caused by the potato virus Y (Potato virus Y; PVY) frequently cause the yield and quality losses. The lack of disease-resistant germplasm of main cultivars is one of the key PVY serious harm. In order to breed disease-resistant germplasm, lots of anti-PVY germplasm resources have been identified at home and abroad such as VAM, V.SCR, as well as the disease-resistant burley tobacco germplasm TN86, TN90and flue-cured tobacco germplasm RY5, NC102and so on. Resistance to genetic characteristics, disease mechanism and the resistance to molecular markers were studied, resistance of most of the PVY resistance sources was controlled by the recessive loci (va) with the linkage drag, such as short blade, a lower yield, the lack of foliage discharge. PVY resistance molecular markers can accelerate the transfer of resistant varieties, such as Randomly Amplified polymorphic DNA (RAPD) and Sequence Characterized amplified region (SCAR) marker. The germplasm RY5, Flue-cured tobacco, has good resistance on PVY necrosis strain (PVYN), but no researches on PVY resistance genetic characteristics and relevant molecular markers have been reported yet. In order to evaluate the breeding potential and utilization of the PVY resistance source RY5, in this study, the resistance genetic characteristics was studied as well as the molecular markers linked to PVY resistance was screened by constructing an F2population and using the method of artificial inoculation.1. The study was carried out using F1, F2, BC1populations from a cross between PVY resistant varieties RY5and PVY susceptible varieties Cokerl76. They were identified by artificial inoculation on seedling stage in greenhouse and the inheritance of resistance was analyzed. The disease severity data collected in21days postinnoculated (dpi) fit the single recessive gene Mendelian model. The disease severity data collected in28dpi shift the single recessive gene Mendelian model.2. To screen the molecular markers linked to PVY resistance of RY5, DNAs of F2population were extracted. Lots of RAPD primers (about600) and a SCAR primer pairs were used for molecular marker analysis. Two tightly linked molecular markers were obtained, and the genetic distance between the RAPD marker O12V3695and the SCAR marker PVYME1and the resistant gene alleles Va locus were2.10cM and2.52cM, respectively. These two markers could be used in PVY resistance breeding assistant selection.3. The marker assisted selection (MAS) for the early materials of the tobacco breeding for disease resistance were carried out by PVY resistance RAPD markers O12V3695and SCAR marker PVYME1, and resistance to black shank Ph gene RAPD markers OPZ-5. These three markers have good prospects in tobacco resistance gene pyramiding breeding.