Agronomic performance of Ciherang near-isogenic lines for nitrogen use efficiency trait in irrigated lowland paddy field

Abstract

Nitrogen (N) is an essential nutrient that affects plant growth and productivity. The consumption of N fertilizer is continuously increasing with the rapid demand for agricultural production. However, the rise in N fertilizer utilization causes higher production costs and leads to a negative impact on the environment. Improvement in nitrogen use efficiency (NUE) of rice plants is therefore important for sustainable rice production to reduce N fertilizer consumption while maintaining high grain yield. To improve the NUE of Indonesian elite cultivars, near-isogenic lines (NILs) with Ciherang genetic background have been developed by introducing genes related to N use efficiency, qRL6.1, and actpk1 through backcross breeding. Preliminary yield trials were conducted to evaluate the agronomic performance of CiherangNILqRL6.1 and CiherangNILactpk1 rice lines under optimum N fertilizer conditions in irrigated lowland fields for two seasons, wet season 2021/2022 and dry season 2022. Observations were performed on flowering time, biomass, yield, and yield component of NILs and Ciherang. The result from this preliminary observation indicated that under optimum N fertilizer, the agronomic performance of the NILs was comparable to Ciherang as the genetic background. Some NILs showed higher grain yield compared to Ciherang and were selected for further experiments to evaluate their performance under different N fertilizer conditions.