关键词: 萝卜, 叶片干枯, SSR标记, 基因定位

Abstract: The withered leaf directly influences plant growth and taproot formation，and affects the high-yield production in radish（Raphanus sativus L.）. Therefore，genetic analysis and molecular mapping of radish withered leaf gene are crucial for the discovery of withered leaf trait happening and its regulatory mechanism. Two radish inbred lines，‘pp12Q-4-2’and‘36-2’，were used as parents for F2 population development. Taproot thickness and weight were measured to analyze the effects of withered leaf trait on radish taproot development on the F2 population. Genetic analysis and gene mapping of withered leaf gene were conducted. Bulk segregation analysis（BSA）was performed on the samples from withered leaves and normal leaves respectively using SSR markers designed based on radish whole genome sequencing for primary gene mapping. More SSR primers were developed for searching closer-linked markers in the primary mapping region of withered leaf gene，and the genetic mapping was drawn. The result showed that withered leaf resulted in chlorophyll content reduction and severely affected taproot growth and developmentin radish. Genetic analysis suggested that withered leaf trait was qualitative and controlled by a single recessive nuclear gene. Normal leaf was dominant to withered leaf. Finally，the withered leaf gene was mapped between two flanking markers saffold89_21520 and scaffold89_21545 on chromosome 7，with a genetic distance of 0.8 cM and a physical distance of 211.63 kb. The predicted region contains a total of 43 candidate genes.

Key words: Raphanus sativus, withered leaf, SSR marker, gene mapping