Viral pathogens significantly affect pear growth and reduce annual production across the world. This study aimed to examine whether conventional virus elimination methods, including thermotherapy (0, 7, 14 and 21 d at 38 °C), meristem culture (less than 0.2 mm, between 0.2 to 0.7 mm and larger than 0.7 mm) and adventitious shoot regeneration from leaf explants can lead to virus-free pear seedlings when compared to chemotherapy (sodium nitroprusside (SNP); 0, 10, 17, 25, 50 and 70 μM). Five pear cultivars (“Abate Fetel”, “Beiruti”, “Dargazi”, “Coscia” and “Louise Bonne”) were investigated to check if those treatments are capable of eliminating three key viruses in pear, namely Apple chlorotic leaf spot virus (ACLSV), Apple stem pitting virus (ASPV) and Apple stem grooving virus (ASGV). The plant’s infection to the viruses was examined using reverse transcription polymerase chain reaction (RT-PCR), followed by applying the treatments, meristem culture and in vitro cultivation. Results surprisingly showed a direct relationship between an increase in duration of thermotherapy and virus elimination. Moreover, it was shown that small size of the cultivated meristem increased the rate of virus elimination, even though the responses were different in terms of the cultivars and viruses. Shoot regeneration had very low efficiency in leaf explants as it could only eliminate ASPV from pear explants. Interestingly, the experiment demonstrated that nitric oxide treatments were more effective in virus elimination than the other treatments. A year later, samples that were diagnosed virus-free were proliferated, rooted and transferred into pots to be used for later propagation and establishment of a mother orchard.

病毒病原体会严重影响梨的生长并降低全世界的年产量。这项研究旨在检查常规的病毒清除方法，包括热疗（在38°C时为0、7、14和21 d），分生组织培养（小于0.2 mm，0.2到0.7 mm之间且大于0.7 mm）和不定芽与化学疗法（硝普钠（SNP）； 0、10、17、25、50和70μM）相比，叶外植体的再生可产生不含病毒的梨苗。对五个梨品种（“ Abate Fetel”，“ Beiruti”，“ Dargazi”，“ Coscia”和“ Louise Bonne”）进行了研究，以检查这些处理方法是否能够消除梨中的三种关键病毒，即苹果褪绿叶斑病毒（ ACLSV），苹果茎点病毒（ASPV）和苹果茎切槽病毒（ASGV）。使用逆转录聚合酶链反应（RT-PCR）检查植物对病毒的感染，然后进行处理，分生组织培养和体外培养。结果出乎意料地显示出热疗时间的增加和病毒清除之间的直接关系。而且，已经表明，即使在栽培品种和病毒方面的反应不同，小尺寸的培养的分生组织也增加了病毒的清除率。芽再生在叶片外植体中的效率非常低，因为它只能消除梨外植体中的ASPV。有趣的是，实验证明一氧化氮处理比其他处理更有效地消除病毒。一年后，被诊断为无病毒的样本激增，