Effect of nitrogen fertilizer on grain yield and zinc concentration in local rice varieties

Abstract

Increasing of Zn in rice grain has been suggested as a way to alleviate Zn deficiency in human population who depend on rice as staple food. The effect of 3 different rates of nitrogen fertilizer at 0, 10 and 20 kg/rai on grain yield and zinc concentration in brown rice of 3 local rice varieties, Pa Ai Goal, Bue Sa Goal and Sang Yod was investigated under field experiment. Applying nitrogen fertilizer at 10 kg/rai increased grain yield in all rice varieties compared with those no nitrogen application with the difference of 19.7-47.3% among rice varieties. Applying nitrogen fertilizer at 20 kg/rai decreased grain yield of Bue Sa Goal at 24.2% from those no nitrogen application, but it was not found the difference in Pa Ai Goal and Sang Yod. Yield components excepting number of filled grain were increased when increasing nitrogen rate at 10 and 20 kg/rai in all varieties. Number of filled grain was highest at 10 kg/rai. Nitrogen rate and rice variety significantly affected on grain zinc concentration in brown rice but no interaction was observed. Song Yod and Bue Sa Goal had the highest grain zinc concentration, while the lowest was found in Pa Ai Goal. The highest grain zinc concentration was found when applying nitrogen fertilizer at 10 kg/rai followed by 20 kg/rai compared with no nitrogen application. There was no correlation between grain yield and zinc concentration in brown rice in all rice varieties. This study indicating that grain yield and zinc concentration could be improved by applying appropriate rate of nitrogen fertilizer with different magnitude of increasing among rice varieties. This information will be useful for the management of nitrogen fertilizer and breeding program to improve grain yield and zinc concentration in rice grain in the future.