Abstract:

The experiment primarily focused on obtaining sterile rootstocks and scions for citrus micro-grafting, and investigated the effects of shoot tip size and grafting methods on the survival rate of in vitro micro-grafting in Ougan citrus. Additionally, the effectiveness of Huanglongbing (HLB) pathogen elimination in grafted seedlings was detected using RT-PCR technology. The results showed that local Zhuluan seeds and Guangxi trifoliate orange seeds exhibited the highest germination rate in the current year. Using Guangxi trifoliate orange seeds as rootstocks, the optimal germination conditions were achieved by disinfecting the seeds with 50% Bijieshi disinfectant for 10-20 minutes and culturing them in a water + agar medium, yielding a sterile germination rate of 43.5%. The survival rates of micro-grafting varied significantly among different rootstock varieties. Among the four rootstock varieties tested, the ease of micro-grafting survival followed the order: Zhuluan>trifoliate orange>fragrant orange>red tangerine. Triangular bud grafting was performed using a stem tip diameter of 0.2-0.4 mm. The survival rate of the stem tip was 42.5% after 30 days grafting. The removal rate of Huanglongbing was 41.6%.

Key words: Ougan (Citrus suavissima Hort. ex Tanaka), micro bud grafting, germination rate, survival rate