Fuente: WIPO "tobacco agriculture" The invention discloses a co-dominant marker primer capable of distinguishing homozygous genotype and heterozygous genotype of a tobacco locus RTSW with resistance to spotted wilt, a distinguishing method and application of the co-dominant marker primer capable of distinguishing the homozygous genotype and the heterozygous genotype of the tobacco locus RTSW with resistance to spotted wilt. The primer is composed of two strands of single-stranded DNA of a primer 1 and a primer 2. The co-dominant marker primer can specifically mark and identify tobacco genome DNA to detect the type of an alleleof the RTSW in the tobacco material genome DNA, and not only can whether or not the locus RTSW with resistance to spotted wilt is contained be identified, but also the homozygous genotype and the heterozygous genotype of the tobacco locus RTSW with resistance to spotted wilt can be distinguished, so that the co-dominant marker primer is reliable and convenient to use, compared with prior markers with resistance to spotted wilt, the co-dominant marker primer has the advantages that the co-dominant marker primer is in close linkage with the target gene RTSW, the accuracy is high, the cost is low, the detection efficiency is high, and the like, the efficiency of screening a variety with the gene RTSW with resistance to spotted wilt of tobacco can be greatly improved, a breeding cycle of the disease-resistant tobacco variety is greatly shortened, and the breeding efficiency is improved.