Abstract: The invention relates to the field of tobacco breeding, particularly to a tobacco plant resistant to TSWD without linkage drag and a method for breeding the same. Provided is a tobacco plant or germplasm resistant to TSWD, which comprises a short RTSW introgressed segment, wherein at least part or entire of the sequence set forth in SEQ ID No.34 is deleted in the short RTSW introgressed segment as compared to the RTSW introgressed segment of tobacco ‘Polalta’. Also provided is a method for screening said tobacco plant or germplasm, in which a tobacco plant or germplasm resistant to TSWD carrying a short RTSW introgressed segment is obtained by detecting NaChr4_2M, NaChr4_8M, NaChr3_62.6M and NaChr3_64.6M linkage drag locus markers. Compared with ‘Polalta’, the tobacco plant or germplasm provided by the invention not only has TSWD resistance, but also reduces or removes linkage drag.

Abstract: The invention relates to the field of tobacco breeding, particularly to a tobacco plant resistant to TSWD without linkage drag and a method for breeding the same. Provided is a tobacco plant or germplasm resistant to TSWD, which comprises a short RTSW introgressed segment, wherein at least part or entire of the sequence set forth in SEQ ID No. 34 is deleted in the short RTSW introgressed segment as compared to the RTSW introgressed segment of tobacco ‘Polata’. Also provided is a method for screening said tobacco plant or germplasm, in which a tobacco plant or germplasm resistant to TSWD carrying a short RTSW introgressed segment is obtained by detecting NaChr4_2M, NaChr4_8M, NaChr3_62.6M and NaChr3_64.6M linkage drag locus markers. Compared with ‘Polalta’, the tobacco plant or germplasm provided by the invention not only has TSWD resistance, but also reduces or removes linkage drag.

Abstract: A TMV resistant tobacco plant containing a short N introgressed segment and a method for breeding the same. A homozygous tobacco plant containing an N introgressed segment is hybridized with a tobacco plant of genotype nn to obtain an F1 progeny tobacco plant of genotype Nn. The F1 progeny tobacco plant is hybridized with the tobacco plant of genotype nn, to obtain population materials for screening to obtain the short N introgressed segment. TMV is inoculated at a seedling stage, and Nn genotype plants showing necrotic lesion are obtained by screening the population materials. The Nn genotype plants are genotyped using a molecular marker TN5.51 primer pair and an N gene-specific molecular marker N1N2 at the right end of the N introgressed segment. A plant found to be negative when tested by the TN5.51 primer pair and to be positive when tested by the N1N2 molecular marker is a plant comprising the short N introgressed segment.

Abstract: A TMV resistant tobacco plant containing a short N introgressed segment and a method for breeding the same. A homozygous tobacco plant containing an N introgressed segment is hybridized with a tobacco plant of genotype nn to obtain an F1 progeny tobacco plant of genotype Nn. The F1 progeny tobacco plant is hybridized with the tobacco plant of genotype nn, to obtain population materials for screening to obtain the short N introgressed segment. TMV is inoculated at a seedling stage, and Nn genotype plants showing necrotic lesion are obtained by screening the population materials. The Nn genotype plants are genotyped using a molecular marker TN5.51 primer pair and an N gene-specific molecular marker N1N2 at the right end of the N introgressed segment. A plant found to be negative when tested by the TN5.51 primer pair and to be positive when tested by the N1N2 molecular marker is a plant comprising the short N introgressed segment.

Abstract: The invention relates to the isolation and the cloning and breeding application of a tobacco mosaic virus (TMV) resistant N?au gene. The invention discloses the nucleotide sequence of the TMV resistant N?au gene shown as SEQ ID NO.1. The amino acids of polypeptide encoded by the TMV resistant N?au gene are shown as SEQ ID NO.2. A non-transgenic TMV resistant tobacco variety can be obtained by transferring an N?au gene which is contained by germplasm resources into a TMV infected popular tobacco variety by conventional breeding means. The N?au gene of the invention has a homologous sequence with high identity rate of nucleotides in the popular tobacco variety, so that it is easy to obtain a shorter introgression segment single plant carrying the N?au gene by conventional breeding, and thereby to obtain a TMV resistant variety with lower linkage drag. The gene can resist both U1 strain and Cg strain of TMV.

Abstract: The invention relates to the isolation and the cloning and breeding application of a tobacco mosaic virus (TMV) resistant N'au gene. The invention discloses the nucleotide sequence of the TMV resistant N'au gene shown as SEQ ID NO.1. The amino acids of polypeptide encoded by the TMV resistant N'au gene are shown as SEQ ID NO.2. A non-transgenic TMV resistant tobacco variety can be obtained by transferring an N'au gene which is contained by germplasm resources into a TMV infected popular tobacco variety by conventional breeding means. The N'au gene of the invention has a homologous sequence with high identity rate of nucleotides in the popular tobacco variety, so that it is easy to obtain a shorter introgression segment single plant carrying the N'au gene by conventional breeding, and thereby to obtain a TMV resistant variety with lower linkage drag. The gene can resist both U1 strain and Cg strain of TMV.