Fuente: WIPO "tobacco agriculture" The invention discloses a codominant SSR (Simple Sequence Repeat) marker closely linked with a tobacco leaf number gene qLN and application of the codominant SSR marker closely linked with the tobacco leaf number gene qLN, the serial numbers of the codominant SSR marker closely linked with the tobacco leaf number gene qLN are PT51248 and TM51844, and the nucleotide sequences of PCR (Polymerase Chain Reaction) amplification products of the codominant SSR marker closely linked with the tobacco leaf number gene qLN are respectively shown as SEQ ID No.1, SEQ ID No.2, SEQ ID No.3 and SEQ ID No.4. The application is the application of the codominant SSR marker closely linked with the tobacco leaf number gene qLN in detecting whether the tobacco leaf number gene qLN exists in tobacco genome DNA (Deoxyribose Nucleic Acid) or not. The codominant SSR marker disclosed by the invention has the characteristics of stability, reliability, simplicity, convenience, rapidness and low cost, so that the molecular marker can be applied to auxiliary selection of the leaf number gene qLN molecular marker in tobacco yield breeding.