| Bacterial leaf spot has been increasing for the last few years and is an important disease on Hamimelon, causing serious losses in Inner Mongolia. In the fields, the symptoms of Hamimelon bacterial leaf spot and bacterial fruit blotch were similar and difficult to be identified. The infection of both pathogens was dominance in alternation. In order to further define the pathogen of Hamimelon bacterial leaf spot and provide a scientific basis for guiding the actual production and breeding for disease resistance, pathogen of the bacterial leaf spot in the Bayannaoer City, Inner Mongolia, was identified. At the same time, resistance of different Hamimelon varieties to bacterial leaf spot was determinate.The strain was isolated from diseased leaves of Hamimelon, back inoculation on young Hamimelon leaves with the isolate produced the same symptom as naturally infected plants. It was identified that Pseudomonas syringae pv. lachrymans was pathogen of local bacterial leaf spot of Hamimelon Leaves, by G-stain reaction, morphological characterization, physiological and biochemical reactions, DNA of pathogenic bacteria strain of bacterial leaf spot were extracted for PCR amplification and sequencing.In order to understand the disease resistance difference and screen varieties of disease resistance, resistance of thirty five kinds of Hamimelons varieties to bacterial leaf spot were identification. According to the statistical results of disease index, there were ten high sensitive varieties, twenty three middle sensitive varieties, and two middle resistant varieties (zaomi 1 and keqimibao). There was no immune and high resistant variety. |
