## 2 Materials and Methods  
### Materials  
Samples of white rice (_Oryza sativa_ L. subsp. _Japonica_) cultivated in 2014 to 2016 were collected from South Korea (\(n=159\)) and China (\(n=182\)). Table 1 shows the cultivation regions of the samples. The South Korean rice samples were cultivated in Gyonggi-do, Gangwon-do, Chungcheongbuk-do, Chungcheongnam-do, Jeollabuk-do, Jeiollanam-do, Gyeongsangbuk-do, and Gyeongsangnam-do. The Chinese rice samples were cultivated in Heilongjiang, Jilin, Liaoning, and Jiangsu, all in Northeast China. The cultivation regions of the South Korean rice samples were in the 34-37\({}^{\circ}\) N latitude and an accumulated temperature range of 2500-4000 \({}^{\circ}\)C. The cultivation regions of the Chinese rice samples were in continental climates with the latitude of 33-47\({}^{\circ}\) N and an accumulated temperature range of 1700-2900 \({}^{\circ}\)C.  
All rice samples were stored in a \(-80\)\({}^{\circ}\)C ultra-low temperature freezer until completely used during the experiment to prevent quality deterioration caused by temperature and humidity changes. The experiment was carried out in 2017. Two days before the experiment, the samples were tempered by maintaining a \(-20\)\({}^{\circ}\)C storage temperature for 24 h, and then stored at 5 \({}^{\circ}\)C for an additional 24 h. The temperature was stabilized for 2 h at room temperature (20 \({}^{\circ}\)C) before acquisition of the hyperspectral fluorescence images. Approximately 50 g of rice was used as the samples in the experiment. Based on the results of previous experiments [23], a black acrylic rectangular sample cell with dimensions of 50 mm \(\times\) 50 mm \(\times\) 5 mm, which did not express fluorescence, was used to obtain the hyperspectral fluorescence images (Figure 1).  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{3}{*}{Nation} & \multirow{3}{*}{Region} & \multicolumn{3}{c}{**2014**} & \multicolumn{3}{c}{**2015**} & \multicolumn{3}{c}{**2016**} \\ \cline{3-10}  & & \multicolumn{3}{c}{**Number of Samples**} & \multicolumn{3}{c}{**Number of Samples**} & \multicolumn{3}{c}{**Number of Samples**} \\ \cline{3-10}  & & \multicolumn{2}{c}{**Short-Medium**} & \multicolumn{1}{c}{**Long**} & \multirow{2}{*}{**Total**} & \multicolumn{2}{c}{**Short-Medium**} & \multicolumn{1}{c}{**Long**} & \multirow{2}{*}{**Total**} & \multicolumn{2}{c}{**Short-Medium**} & \multicolumn{1}{c}{**Long**} & \multirow{2}{*}{**Total**} \\  & & **Grain** & & **Grain** & & & & & & & \\ \hline \multirow{8}{*}{**Sooth Korea Korea**} & Gyonggi-do & 12 & 0 & 12 & 17 & 0 & 17 & 13 & 0 & 13 \\  & Gangwon-do & 7 & 0 & 7 & 8 & 0 & 8 & 6 & 0 & 6 \\  & Chungcheongbuk-do & 3 & 0 & 3 & 4 & 0 & 4 & 1 & 0 & 1 \\  & Chungcheongnam-do & 4 & 0 & 4 & 4 & 0 & 4 & 5 & 0 & 5 \\  & Jeollabuk-do & 6 & 0 & 6 & 5 & 0 & 5 & 12 & 0 & 12 \\  & Jeiollan-do & 11 & 0 & 11 & 6 & 0 & 6 & 14 & 0 & 14 \\  & Gyeongsangbuk-do & 6 & 0 & 6 & 1 & 0 & 1 & 8 & 0 & 8 \\  & Gyeongsangnam-do & 1 & 0 & 1 & 2 & 0 & 2 & 0 & 0 & 0 \\  & Etc. & - & 0 & - & 1 & 0 & 1 & 0 & 0 & 0 \\ \hline \multirow{8}{*}{**China**} & Heilongjiang & 9 & 23 & 32 & 14 & 17 & 31 & 15 & 4 & 19 \\  & Jilin & 4 & 4 & 8 & 7 & 3 & 10 & 13 & 8 & 21 \\ \cline{1-1}  & Liaoning & 6 & 0 & 6 & 26 & 0 & 26 & 21 & 0 & 21 \\ \cline{1-1}  & Jiangsu & 2 & 2 & 4 & 1 & 1 & 2 & 2 & 0 & 0 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Cultivation regions of domestic (South Korean) and imported (Chinese) rice.