1. Department of Horticulture, Sunchon National University, Suncheon 540-950, Korea
2. Apple Research Station, NARO Institute of Fruit Tree Science, 92-24 Shimokuriyagawa, Morioka, Iwate 020-0123, Japan
3. NARO Institute of Fruit Tree Science, 2-1 Fujimoto, Tsukuba, Ibaraki 305-8604, Japan