Construction Of A Genetic Map Based On SSR Markers And The Primary QTLs Mapping Of The Resistance To Phytophthpra Infestans In Tetraploid Potato

With the planting area enlarging and the yield increasing in potato, which has been the fourth important crop following wheat, rice and maize. While the developing of potato planting, potato has been threatened by a variety of plant diseases and insect pests, in which late blight is the most. Late blight has caused the yield and quality of potato fall rapidly, and impacted the healthy development of potato industry seriously. It is an important strategy for late blight management by breeding variety of resistance to P. infestans. Quantitative trait locus(QTL) is an effective method to study the resistance to P. infestans. This method could identify the relative location of each minor gene in chromosomes and the rate of contribution of resistance to P. infestans. To achieve this goal, choosing the parents on purpose and aggregating the identified gene of resistance to P. infestans. In this study, F1 population including 190 lines derived from two cultivated potato parents(female parent is ‘Atlantic’ and male parent is ‘Longshu No.6’)was used for genetic linkage map construction based on 122 SSR markers, and detected the QTLs of resistance for P. infestans by interval mapping.The primary consequence in this study:1. The result shows that there has significant difference in the resistance to P. infestans. of parents from the t-test. So it is possible to use the cross population from the parent combination to identify the QTL loci. 2. 122 SSR primers selected from 240 SSR primers of combination show high polymorphism, which could be used for linkage map construction. 3. Genetic linkage map construction: 122 SSR primers were used as a genetic linkage map, which consisted of 12 linkage groups with 171 SSR markers. 4. 7 QTLs of resistance to P. infestans. were identified and named as pi05, pi06-1, pi06-2, pi07-1, pi07-2, pi10 and pi11 respectively, which were located on L5, L6, L7, L10 and L11. The distance from QTLs to nearest SSR markers were 1~13 c M. The max distance is between pi05 located on L5 and the SSR primer STGOOO7-271; the min distance between pi06-2 located on L6 and the SSR marker S183-210 and between pi07-1 located on L7 and the nearest SSR marker S48-460 is 1 c M. 7 QTLs explained the genetic variance of 17.37%, 34.87%, 31.13%, 29.31%, 65.68% and 28.70% respectively.Genetic linkage map of tetraploid potato construction in this study could integerate genetic linkage map of potato ulteriorly. 7 QTLs not only provide reasonable theoretical foundation and derection for refined location of objective genes, but also offer guiding significance for molecular marker assisted selection in potato.