Physiologic race identification method for Phytophthora parasitica var. nicotianae

Abstract

The invention relates to a physiologic race identification method for Phytophthora parasitica var. nicotianae. Aiming at tobacco black shank which is a soil-borne disease, field pathogen infection ways are simulated. The method includes: propagating the Phytophthora parasitica var. nicotianae; making bacterial discs, inoculating to wheat grains subjected to moist heat sterilization, well shaking, and culturing at 26DEG C until each wheat grain is uniformly covered with hyphae; inoculating to soil with seedlings of differential hosts NC 1071, L8 and Hick's or Mini Gold 1025 in 3-5-leaf stage, wherein each seedling is inoculated with two grains; checking death count of the differential hosts 12 days after inoculation, determining that the seedlings are susceptible if more than two of three differential hosts are dead, and otherwise, determining that the seedlings are resistant; determining corresponding physiologic races according to resistance and susceptibility reaction. The method has advantages of high operability, high accuracy, high speed, simple equipment and small floor area and can be used for physiologic race identification of large-scale Phytophthora parasitica var. nicotianae in a greenhouse in a short time.

Description

technical field [0001] The invention relates to the technical field of agricultural plant protection, in particular to a method for identifying physiological races of tobacco blackleg pathogen. Background technique [0002] Tobacco black shank (Tobacco Black Shank) is a worldwide devastating tobacco disease caused by Phytophthora parasitica var. -50%, up to 70% in severe cases, and even death in pieces. Practice has proved that only the comprehensive control with disease-resistant varieties as the core can effectively control the damage of tobacco black shank. According to reports at home and abroad, there is a phenomenon of physiological differentiation of tobacco black shank bacteria, which brings difficulties to disease-resistant breeding and application of disease-resistant varieties. Therefore, the identification of physiological races is the key to solving these problems, and provides a scientific basis for tobacco disease-resistant breeding and the rational distribu...

AI Technical Summary

Problems solved by technology

However, these inoculation methods, except the zoospore root irrigation method, are all man-made wounds, and the degree of disease is much heavier than the actual infection in the field. The zoospore irrigation method is cumbersome to prepare zoospore suspension, and the process is relatively complicated.

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