This experiment evaluated grain yield and anthocyanin content in the grain of two purple glutinous
rice varieties grown under two levels of nitrogen (N) fertilizer and two water management conditions. Two purple
glutinous rice varieties, Kum Doi Saket (KDK) and CMU122, were grown in Sansai soil in a pot experiment. Two
levels of N fertilizer, 70 (N70, low N) and 210 (N210, high N) mg N/kg soil, and two water regimes, submerged
and aerobic, were applied. The results showed that increasing N from N70 to N210 increased grain yield in both
varieties. In KDK, high N in submerged soil had twice higher grain yield than that with low N while there was only
a slight effect of N on grain yield in aerobic soil. In CMU122, high N rate had about twice higher grain yield than
that with low N in both water conditions. Interactions between varieties of rice and nitrogen also affected the purple