1. Professor, Faculty of Agriculture, Kyushu Univ., Fukuoka, JP 812-8581, e-mail: ohtsubo@bpes.kyushu-u.ac.jp
2. Graduate Student, Graduate School of Bioresource and Environment, Kyushu Univ., Fukuoka, JP 812-8581.
3. Associate Professor, Faculty of Agriculture, Kyushu Univ., Fukuoka, JP 812-8581, e-mail: higashi@bpes.kyushu-u.ac.jp
4. Assistant Professor, Faculty of Agriculture, Kyushu Univ., Fukuoka, JP 812-8581, e-mail: motohei@bpes.kyushu-u.ac.jp