Studies On Resistance Index Of Hamimelon Varieties To Acidovora Avenae Subsp. Citrulli

Fifteen varieties of Hamimelon were identified by the methods of artificial inoculation .It was found that the difference was obvious among varieties. The immune varieties were not found ,the high resistance varieties accounted for 26.67%,the middle resistance was 33.33%,the middle sense was 13.33%,the sense was 26.67 %. The leaves of Hamimelon with different resistance were inoculated to Acidovorax avenae subsp. citrulli , then the change in the defendant enzyme activities the content of lignins and the wax. The results that there was no relation between the activities of SOD ,wax content of leaves and Hamimelon resistance to Acidovorax avenae subsp. Citrulli after inoculation. In the resistant variety and the susceptible variety, the maximum value of the activitiy of PPO were appeared in 2d after inoculation, there was negative relation between the activities of PPO and the resistance of Hamimelon to Acidovorax avenae subsp. Citrulli. The activities peak of POD and PAL in the leaves of resistant cultivars were much earlier than that insusceptible cultivars After inoculation, the activity of PAL was correlated with resistant tolerance. So, the peak of PAL in leaves could be used as the criterion to evaluate the resistance to the disease. The contents of lignin in the resistant host was higher than that in the susceptible one before and after inoculation, the resistant varieties appeared dominance. There was significant difference between wax content of seed-coat of the resistance variety and the susceptible variety, wax content of the resistant variety was higher than that of the susceptible variety. So, wax content of seed-coat can be used as the referenced criterion to evaluate the resistance to the disease.