1. Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma 630–0101, Japan (H.S., S.T., M.I., H.S., M.F., T.N., F.-S.C., A.I.);
2. Division of Natural Science, Osaka Kyoiku University, Osaka 582–8582, Japan (G.S.);
3. Faculty of Agriculture, Iwate University, Morioka 020–8550, Japan (M.W.); and
4. Research Institute of Seed Production Company, Sendai 989–3204, Japan (K.H.)