Mechanism And Inheritance Of Resistance To Turnip Mosaic Virus In Non-Heading Chinese Cabbage

The objective of this paper was to study the mechanism and inheritance of resistance to Turnip Mosaic Virus in non-heading Chinese cabbage. The results were as follows:1. 8 Non-heading Chinese Cabbage varieties or lines for resistance response to TuMV were evaluated by disease nursery artificial induction in the field and the greenhouse.The results showed that the resistance response during the seedling stage can be used as the field resistance response, the right inoculation time is trifoil-wholehearted stage ,the inoculating concentration is 150μg/mL.2. Four inbred lines of different resistance to turnip mosaic virus of non-heading Chinese cabbage 003-R-5,Y₃-R-2,109-S-8 and 003-S-13 were conducted in studying the relationship between the resistance and the activity of SOD,CAT,PAL,PPO.Test the activity of SOD,CAT,PAL,PPO after the inoculation at seeding stage and made a simple linear regression analysis associated with the disease index. The results were showed as follows: the resistance varieties had higher values of CAT,PAL,PPO and lower SOD than the susceptible varieties in uninfected plants, these four protective enzyme activities increased significantly after inoculation and the resistance varieties were more sensitive than the susceptible varieties. Correlative analysis revealed that SOD,CAT,PAL,PPO were positive correlated to the resistance to turnip mosaic virus of non-heading Chinese cabbage inbred lines, the correlate coefficient were 0.776,0.9591^*,0.9774^*,0.9991^**;respectively. The activity of PPO correlated very significantly with the resistance , the activity of PAL of 8th day leaves after inoculation correlated significantly with the resistance (r=0.9575^*) .3. Two sets of data (003-R-5×003-S-4 and 014-R-4×109-S-8)for the P₁,P₂,F₁,BC₁,BC₂ and F₂ populations derived from four parent inbred lines with different resistance to turnip mosaic virus were used to investigate the inheritance of resistance in non-heading Chinese cabbage using mixed major gene plus polygenes inheritance model in 2005 and 2006.. The results from the joint segregation analysis of the six generations showed that the resistance in two sets was controlled by one pair of additive-dominant genes plus additive-dominant polygene(D-1). The dominant effect controled by major gene was partly negative dominant. The major gene was given prior to the improvement of resistance in Non-heading Chinese cabbage , and the negative effect of dominant gene was given attentions synchronously. The major gene heritability is lower than the polygenes heritability. Variance of environment is high in total variance. It is easy to be affected by environment.