Abstract: The present invention “A Molecular marker Nicotine Associated SNP 1 for identifying high or nicotine content of tobacco and its kit as well as use thereof” belongs to field of molecular biology technology. The molecular marker Nicotine Associated SNP 1 is a SNP Nitab4.5_0002539:95304 A/G at base No. 95304 of Genomic segment No. 0002539 in tobacco genome version of Nitab v4.5 Genome Scaffolds Edwards2017. The present invention can accurately identify and screen tobacco germplasm resources with high or low nicotine content, and the screened tobacco can be directly used for breeding new tobacco varieties without transgenic methods. At the same time, gene sequence where the SNP site is located can also significantly activate promoters of key enzyme genes in nicotine synthesis pathway.

Abstract: The disclosure provides a method of screening tobacco germplasm for resistance to Alternaria alternata by ripening seedling leaves. The method includes ripening seedling leaves, spray inoculation, disease induction, and evaluation of disease resistance. Dense planting, fertilizer control, and potassium increment were used to forcibly ripening seedling leaves. A hospitable environment was simulated to induce disease in the ripened leaves. These treatments reduce differences in leaf maturity and avoid environmental changes. The technique of the disclosure provides greater accuracy and repeatability than the current technique of screening brown spot resistance, and offers the advantages of simple operation, reduced cost, space requirement, and labor intensity, high selection efficiency, and an accurate screening of tobacco phenotypes with resistance to brown spot, etc., used for large-scale screening of tobacco varieties with resistance to brown spot.

Abstract: The disclosure provides a method of screening tobacco germplasm for resistance to Alternaria alternata by ripening seedling leaves. The method includes ripening seedling leaves, spray inoculation, disease induction, and evaluation of disease resistance. Dense planting, fertilizer control, and potassium increment were used to forcibly ripening seedling leaves. A hospitable environment was simulated to induce disease in the ripened leaves. These treatments reduce differences in leaf maturity and avoid environmental changes. The technique of the disclosure provides greater accuracy and repeatability than the current technique of screening brown spot resistance, and offers the advantages of simple operation, reduced cost, space requirement, and labor intensity, high selection efficiency, and an accurate screening of tobacco phenotypes with resistance to brown spot, etc., used for large-scale screening of tobacco varieties with resistance to brown spot.

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.