Assessment of virus eradication methods from infected in vitro-grown apricot cultures

In vitro culture of apricot cultivars 'Qaysi', 'Shams', and 'Ordubad', infected with Apple chlorotic leaf spot virus (ACLSV), Apple mosaic virus (ApMV), and Tobacco ring spot virus (TRSV) was used in this study. We investigated whether electrotherapy (0, 30, 40, 50, and 100 mA for 15 min), combining thermotherapy (38 degrees C for 7 days) with shoot tip culture, chemotherapy (ribavirin at 0, 25, 50, 75, and 100 mg L-1 for 30 days) with shoot-tip culture, or cryotherapy (incubating shoot-tips in plant vitrification solution-2 (PVS2) for 40 min) could effectively eradicate ACLSV, ApMV, and TRSV from virus-infected cultures. After treatments, shoot tips were cultured in vitro for 4 months before testing for the presence of viruses, and virus-free plants were grown in greenhouse for 18 months prior to retesting for the presence of the viruses. The highest virus elimination rates of 90-100% were obtained in combining thermotherapy with shoot tip culture (1.1-2.0 mm). Chemo (25 mg L-1)-and electro (40 mA)-treatments were also effective for producing virus-free planting material with frequencies of 75-100% and 40-60%, respectively. Cryotherapy treatment resulted in rates of 60-80%.The highest efficiency of virus eradication was detected in chemotherapy (58.6-93.3%), cryotherapy (60-80%), and thermotherapy (54-80%), respectively. According to our results, production of virus-free regenerants would be feasible in Prunus armeniaca L. providing proper therapeutic methods are adopted as regards the type of infecting virus and the host variety.