QTL Analysis Of Cold Tolerance For Physiological Traits In Winter Rapeseed (Brassica Rapa L.)

The different cold resistance Brassica rapa L. variety “Longyou7” and“Longyou9” were used as parents hybridized F2population, and molecular tagging ofQTLs for cold resistance traits in B. rapa will provide a basis for study on molecularmarker-assisted selection and cloning of cold resistance related genes. The resultsprovide theoretic and substance basis for development cold resistant varieties. Themain result summarized follow.1.The superior cold resistance B. rapa variety “Longyou7” and general coldvariety “Longyou9” were used as parents and a F2mapping population with103individuals was constructed. The results of material analysis showed that thephenotype data of population in the F2populations was approximately normallydistributed with slight skew, embodies a characteristic of quantitative genes control.That suggested that the constructed F2population was an ideal population for linkagemapping analysis.2. A molecular linkage map was constructed. Screening pairs of51SSR and264InDel primers from different sources for the parents, and15SSR and24InDelprimers were selected for further analysis103of F2lines by using the39primers.Referenced for the existing map of B. rapa and QTL software to found out the geneticdistance. A genetic map which is included39makers was constracted. The39QTLswere detected from10chromosomes.3. Based on molecular marker genetic map and QTL software ICIM QTLIciMapping, a total of24QTLs were detected for SOD activity, POD activity, CATactivity, MDA content, free proline content and soluble protein content from10chromosomes. Those QTLs were able to explain11.1783%～81.1753%of phenotypic variation. The dominant effects of10QTLs were positive effects, LOD values werebetween3.2787-163.7958.4. The data showed that the regions BrID90127-BrID10421， BrID10421-BrID10709and BrID10709-BrID101165on2A, BRMS034(R5)-Ra3-H10on5A,Ra1-F06-Ra2-D04on6A, BrID10839-Ra2-E12on8A, BrID90115-Ra2-E07on10A were common regions shared by multi-traits. They were crucial regions forfurther elucidating genetic analysis of cold-tolerant traits.