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.