| 【Objective】In order to facilitate the research of melon blight and screen the blight-resistant cucurbit
varieties rapidly, a resistance-identification method for cucurbit phytophthora blight was established.【Method】The
seedlings of cucumber disease-resistant materials and disease-infected materials were inoculated by four inoculation
methods, such as root pouring, spore-spraying, root soaking and in vitro inoculation of mycelial pellet, and the most
convenient and effective identification method was determined by comparing the incidence rate, onset time and operation
procedures.【Result】All the four methods could be used to identify the resistance to cucumber phytophthora blight, but
the identification effects were different significantly. Root pouring, spraying, and root soaking are applicable to solution with
a concentration of 102 spores /mL. However, the operation of these methods was complex and the inoculation efficiency was low. As for in vitro inoculation of mycelial pellet, a piece of mycelial pellet with the diameter of 2 mm was directly inoculated
on the back of excised cotyledons and put in a petri dish with wet filter paper. Then the phenotype was observed after being
moisturized for 24h. And the resistance of cucumber materials was identified by calculating the size of the disease spot. By
using this method, 40 pieces of cucumber materials with different resistance were identified. It was found that only 4 cucumber
cultivars (PE40, PE119, PE120, PE185) were resistant to phytophthora blight, and 90% of them were susceptible or highly
susceptible.【Conclusion】The results showed that the inoculation of excised cotyledon of mycelial pellet is a fast and effective
method to identify cucurbit phytophthora blight. This method can identify hundreds of materials at one time without spores while
preserving susceptible materials or intermediate materials, thus improving the identification efficiency and laying a foundation
for resistance breeding to cucurbit phytophthora blight. |
