Pereliminary Study On DUS Testing Of Non-Heading Chinese Cabbage

In order to screen characters for DUS testing, it was studied the botanical characters, quality characters and heat resistance in non-heading Chinese cabbage and then formed the preliminary DUS testing guidelines. results were as follows:1. Four qualitative binary characters, nine qualitative polymorphic characters and eleven quantitative characters of 27 main non-heading Chinese cabbage cultivars were observed in the field. The distinctness, uniformity and stability of these cultivars were analyzed by using coefficient of variation, T-test.The results showed that the uniformity of all qualitative binary characters and most qualitative polymorphic characters were good for all cultivars, while those quantitative characters were influenced by the environment significantly .The stability of qualitative binary characters were best and qualitative polymorphic characters were relatively good, while quantitative characters were bad. 27 cultivars are obviously Distinctness. On the basis of analysis, it was screened 18 pre-requisite characters and 5 assistant characters.2. It was studied Quality characters of 27 non-heading Chinese cabbages. The results showed that the content of dry matter is between 4486.72～9095.26 mg/100g.FW, "Maertou" has the highest and "Gaobaigeng" the lowest content of dry matter; The content of Cellulose is between 254.14～1126.98 mg/100g.FW; The content of organic acid is between 755.1～1915.9mg/100g.FW; The content of Soluble sugars is between 463.51～5191.13mg/100g.FW; The content of Soluble protein is between 679～3650mg/100g.FW; The content of Vc is between 15.44～32.45 mg/100g.FW.3. It was studied the effects of heat stress on leaf membrane liquid peroxidation and endogenous protective enzymes in two non-heading Chinese cabbage seedlings. The results showed that as the time went on and the stress gradually increased , leaf membrane liquid peroxidation ascended ,the malondialdehyde content increased evidently. The activities of the peroxidase enzyme ( POD) and the superoxide dismutase ( SOD) in the two cultivars varied under heat stress. The activities of SOD, CAT and POD turned out to ascend in the beginning and then descend. The activities of the heat-resistant seedlings turned out to change gently, the others...