Effects of nitrogen and water managements on yield and anthocyanin content in two purple glutinous rice varieties

Abstract

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 color in the pericarp of rice grain. Nitrogen also affected anthocyanin content in the rice grain of both varieties. In KDK, increasing N rate from N70 to N210 decreased anthocyanin content in the rice grain while the response was different in CMU122, with anthocyanin increasing with the N rate. The intensity of the purple color of the pericarp was, by visual observation, found to correlate with anthocyanin content in the rice grain. The results from this experiment will be useful for grain yield and quality control as well as the selection in the breeding program for the improvement of purple rice.