Performance of Nitrogen-Use Efficient Nerica4 Rice Lines in Indonesian Rain-Fed Ecosystems

Rice absorbs only 30-40% of N fertilizer application. Therefore, one of the solutions is using a variety of rice that absorbs N more efficiently. This experiment is aimed at determining the yield parameters, NUE performance, and nitrous oxide flux of NERICA4 transgenic lines and NERICA4-wild type in rain-fed agro-ecosystems at different doses of N fertilizer during a confined field trial. The experiment was conducted in Central Java, Indonesia, during the 2017/2018 rainy season. The experiment used a factorial randomized block design with four replications. Three transgenic lines of NERICA4 (NUE2, NUE9, NUE12) and NERICA4-WT were used as the main plot and N fertilizer rates (60, 120, and 180 kg N/ha) were used as the subplot. The results showed that an increase in the N fertilizer rate generally improved the plant height and the tiller number of NERICA4-NUE lines. The tiller numbers of NERICA4 NUE lines were higher than NERICA4-WT on high N dosages. There was a strong correlation between the N uptake and the grain yield. The analysis showed that all NERICA4-NUE lines use N more efficiently than NERICA4-WT, significantly at 60 kg N/ha with higher total grain than NERICA4-WT. NERICA4 NUE9 tended to emit lower nitrous oxide flux than other NERICA4-NUE and NERICA4-WT.