Evaluation on the resistance to tobacco virus disease of tobacco dominating cultivars in Guangdong province

In order to evaluate the resistance to TMV and CMV of 7 main cultivars from Guangdong province，by using concentration grades（ 0，1∶10，1∶100，1∶1 000，1∶10 000，1∶100 000） of TMV-infected tobacco leaves as contrasts on Nicotiana glutinosa，the seedlings of 7 cultivars of tobacco（ K326，YUNYAN87，RG17，9601，9032，MSK326，MS96-7），were respectively inoculated at the concentration of 1∶10 000 by method of common friction inoculation. According to the results of agricultural product characters on the 70th day after inoculation，YUNYAN87，RG17 and 9601 were better in agricultural product characters；According to the DI（Disease index） on the 70th day after inoculation，MS96-7 was the lowest（ 81.06），and 9032 was the highest（95.46）；According to the incidence of disease on the 30th day after inoculation，MS96-7 was the lowest（71.21％），RG17 was the highest（ 100.00％）. There was no immune or high-resistant cultivar to TMV in Guangdong province，and MS96-7 was identified as middle-resistant cultivar to TMV，the others（ K326， YUNYAN87，RG17，9601，9032，MSK326） were identified as middle-susceptible cultivars. By using method of common friction inoculation，tobacco seedlings of 7 cultivars were respectively inoculated by CMV at the concentration of 1:40 dilution. From the results of DI on the 20th day after inoculation，the percentage of seedlings with classic symptom on the 9th day after inoculation，YUNYAN87 was identified as the most resistant to the movement of CMV among 7 cultivars，9601 was identified as the most susceptible cultivar among 7 cultivars. And RG17 was identified as the high-susceptible cultivar，the resistant levels of others were middle and high-susceptible to CMV. There was no immune，high-resistant cultivar to TMV in Guangdong province，and there was no immune， high-resistant or middle-resistant cultivar to CMV.