Establishing The Methods Of Pitaya Canker Disease Resistance Identification And Selection Of Resistance Resources

Pitaya was an important tropical and subtropical fruit trees. It was combines fruit, flowers, vegetables, health care, and tourism as a whole, which had a high economic value. In recent years, with the pitaya planting area was increased, pitaya canker disease was outbroke in a large area of Guangdong province. At present, pitaya canker disease was controlled mainly by chemical control strategy. With the pollution of chemicals on the environment was becoming increasingly, the screening and application of resistant varieties was a reasonable way to solve the problem. It is important to establish an easy operation and reliability in test results for resistance identification system for disease resistance breeding. This study was through screened the inoculum concentration, inoculum temperature and inoculum bud-age experiment to establish the initial of the pitaya resistance evaluation method, then a convenient and feasible resistant-identification method to canker disease of pitaya was established, the resistance of 21 pitaya materials to pitaya canker disease were identified, and the change of SOD, POD, PAL, CAT enzyme activities in leaves after inoculation were also analyzed. The results were as follows:1 ? An artificial inoculation method for pitaya canker disease identification was established, the best inoculation concentration of pitaya was 1×105 spores/m L, the best bud-age was 10 days, the best temperature was 28?.2 ?According to disease index and incubation, enacting disease resistance classification standard of pitaya canker disease. On the basis of the classification standard, 21 pitaya materials were appraised for the resistance to pitaya canker disease, the result was that there were 1 resistant material, 4 medial-resistant materials. The medial-resistant materials to the above germplasm accounted for 23.8%, to carry out the ulcer disease resistance breeding is a valuable material.3? This study suggests that by looking at the stomatal density of pitaya and forms,The experimental results showed that the stomata density was significant different among cultivars and in negative correlation with the disease, the smaller stomata density, thestronger the resistance. It follows that stomatal density can be used as the auxiliary basis of disease resistance identification.4? The research of enzymatic activity shows that: After inoculation, SOD, POD, PAL,CAT activity have been increased, and the enzymatic activity in the medial-resistant material is higher than the enzymatic activity in the high-susceptible material, and the former also has faster increased speed and negative correlation with the disease index of the in vitro inoculation identification. After inoculated with different materials of SOD, POD, PAL activity and negatively correlated with disease index.