Dear Hiroshi, I am not acquainted with maize cultivar NC+4616, but when I was still at CIMMY, we determined from some tropical lowland maize cultivars an average duration of the linear grain filling phase of about 31.5 days, which corresponds with your 800/25=32. During this phase, about 85% of the final grain weight was accumulated. The other 15% was accumulated during the lag and terminal phases. Adding 15% to your 9500 kg ha-1 would bring you close to 11 t ha-1. The maximum grain filling rate during the linear phase may be higher than your 8 mg kernel-1 d-1. We, for instance, determined an average close to 10 mg kernel d-1. If you add another 20%, you reach about 13 t ha-1. Do you have any experimental data? What are usual grain yields? Regards, Anne Elings ---------------------------------------------------------------------------- ------------ Anne Elings Department of Crop Production and Ecology Research Institute for Agrobiology and Soil Fertility Wageningen University and Research Centre Bornsesteeg 65, 6708 PD Wageningen P.O. Box 14, 6700 AA Wageningen tel. +31 - 317 - 475826 fax + 31 - 317 - 423110 email [log in to unmask] internet http://www.ab.wageningen-ur.nl/ ---------------------------------------------------------------------------- ------------