초록
사과 '홍로' 품종은 품질이 우수하여 재배면적이 증가되고 있는 중요한 품종으로 최근 일부 농가에서 과실 크기가 작아지면서 과육이 딱딱해지고 과즙이 거의 없어지는 소과증상이 발생되고 있어 재배현장에서 문제가 제기되고 있다. '홍로' 품종의 소과증상은 주요 재배지역에서 조사한 결과 조사농가당 홍로품종 재배주수의 평균 12%정도 발생되고 있었으며 ELISA에 의한 바이러스 진단 결과 소과 발생나무에서 고농도의 ACLSV가 100% 검출되었다. 즙액 접종한 C. quinoa에서 ACLSV가 분리되었으며, 접목 접종한 목본지표식물에서도 잎 상편생장 및 줄기괴사 병징을 나타내어 접목전염성이 확인되었다. 소과증상의 원인 구명을 위해 열처리와 생장점배양으로 육성된 바이러스 무독주에 인위적으로 ACLSV 등 바이러스를 접목접종 한 다음 결실된 과실의 특성을 조사한 결과 ACLSV 접종주에서 소과증상이 발생되는 것을 확인할 수 있었다. 결론적으로, 소과증상을 일으키는 주된 요인이 ACLSV 감염에 의한 것으로 판단되며 국내 육성종인 '홍로' 품종은 ACLSV에 대한 감수성 품종으로 분류될 수 있을 것으로 판단된다.
'Hongro' is one of the most important apple cultivars whose growing area is increasing because of its good quality. Recently fruit shrinking symptom causing decrease of fruit size, juice, and quality, appears in some commercial 'Hongro' orchards. The average frequency of occurrence of fruit shrinking symptom was 12 % of total trees investigated and Apple chlorotic leaf spot virus (ACLSV) was detected from all the trees showing fruit shrinking symptom by ELISA. A typical virus infection symptom of leaf epinasty and stem necrosis appeared on woody indicators, Spy227 and Virginia crab grafted with infected trees and all the grafted trees showed positive reaction to ACLSV antiserum by ELISA. It was proved that ACLSV can be easily transmitted by grafting. ACLSV was also isolated from the leaves of C. quinoa inoculated with sprouting leaf sap of infected trees. To prove that the fruit shrinking symptom was caused by ACLSV infection, ACLSV-infected scion was grafted on virus-free 'Hongro/M9' and the fruit characteristics were investigated. Consequently the same symptoms of fruit size and juice decreasing were observed from the trees grafted with ACLSV-infected scion. Therefore, it is suggested that the fruit shrinking symptom is caused by ACLSV infection and 'Hongro' can be classified as sensitive cultivar to ACLSV.
