1. Center for Ecological ResearchKyoto University520‐2113OtsuShigaJapan
2. Lowland Crop Research DivisionNARO Western Region Agricultural Research Center721‐8514FukuyamaHiroshimaJapan
3. Department of Mathematical and Statistical MethodsWageningen University and Research, BiometrisP.O. Box 166700 AAWageningenThe Netherlands