1. Faculty of Agriculture, Iwate University, Morioka 020-8550, Japan1
2. Department of Citriculture, National Institute of Fruit Tree Science, Kuchinotsu 859-2501, Japan2
3. Apple Research Center, National Institute of Fruit Tree Science, Morioka 020-0123, Japan3
4. Shikoku National Agricultural Experiment Station, Zentsuji 765-8508, Japan4