Table 4. Effects of CO2 concentrations (EC, elevated; AC, ambient) and Kinetin (KN, treat; CN, control) on percentage of unfilled spikelets sorted by different specific gravity (SG) solution for Koshihikari and Takanari in the 2016 growing season at the Tsukuba FACE site (n=4). 1% of spikelets that floated on the ethanol solution (SG < 0.86); 2% of spikelets that floated on the water but sank in the ethanol solution (0.86 < SG < 1.0); 3% of spikelets that floated on the ammonium sulfate solution but sank in the water (1.0 < SG < 1.06); 4CE: EC effect, (EC/AC-1) x 100; 5Kinetin effect: (KN/CN-1) x 100; 6Statistically significant effects are indicated ***, P < 0.001; **, P < 0.01; *, P < 0.05; The value indicates the probability between 0.05 and 0.1; ns, not significant.