Studies On Elimination Of Pathogen Of Citrus Huanglongbing And Citrus Tristeza Virus With Shoot-Tip Grafting And Molecular Determination

In this study, the shoot-tips of Citrus sutsuma Marc from Xinyu city of Jingxi province were used as explants to perform shoot-tip grafting (STG) , 169 STG plantlets were obtained; all the mother plants of Citrus sutsuma Marc cv Daoye,Citrus sutsuma Marc cv Shiwen,Citrus grandis osback cv Feicui,Citrus grandis osback cv Chuhong,Citrus Suavissima Hort ex Tanaka and 186 STG plants ever since 2003 have been determinated with PCR and RT-PCR. We evaluated the existence of pathogery of BLO and CTV. In addition, we studied the effect of Virazole treatment on the shoot-tip grafting survival rate, the main results are as following:1. 186 STG plants of 1-3 years old were identified by PCR technique, BLO pathogen was not found, the virus-free rate was 100%.2. We detected the five varieties citrus mother plants and STG plants with RT-PCR, as a result, all of the mother plants could amplified Tristeza bands, but the highest virus-free rate of grafting plants only was 61.1%, and the results may prove that not all shoot-tip grafting can remove the CTV completely.3. Contrasted the effect of different concentration virazole on grafting survival rate, and the optimum of viratole is 20mg/L.