dep1 improves rice grain yield and nitrogen use efficiency simultaneously by enhancing nitrogen and dry matter translocation
Liying Huang, Xiao-xiao LI, Yun-bo ZHANG, Shah Fahad, Fei Wang
Abstract
The rice cultivars carrying the dep1 (dense and erect panicle 1) have the potential to achieve both high grain yield and high nitrogen use efficiency (NUE). However, few studies have focused on the agronomic and physiological performance of those cultivars associated with high yield and high NUE under field condition. That’s why, we evaluated two near-isogenic lines (NILs) carrying DEP1 (NIL-DEP1) and dep1-1 (NIL-dep1) gene under the Nanjing 6 background at 0 and 120 kg N ha-1 for yield performance and NUE. Grain yield and NUE for grain production (NUEg) were 25.5 and 21.9% higher in NIL-dep1 in comparison with NIL-DEP1 averaged across N treatments and planting years, respectively. The yield advantage of NIL-dep1 over NIL-DEP1 was mainly due to larger sink size (i.e., higher total spikelet number), grain filling percentage, total dry matter production and harvest index. N utilization rather than N uptake contributed to high yield of NIL-dep1. Significantly higher NUEg in NIL-dep1 was associated with higher N and dry matter translocation efficiency, lower leaf and stem N concentration at maturity, and higher glutamine synthetase (GS) activity in leaves. In conclusion, the dep1 improved grain yield and NUE by increasing N and dry matter transport due to higher leaf GS activity during grain filling period under field condition.