Agronomic performance of inbred and hybrid rice cultivars under simplified and reduced-input practices

Hybrid rice has higher yield potential than inbred rice under optimum growing conditions when large amount of resources are provided. However, little attention has been paid to the performance of inbred and hybrid rice cultivars under simplified and reduced-input practices (SRIP). Field experiments were conducted to evaluate the performance of widely grown inbred (Huanghuazhan, HHZ) and hybrid (Yangliangyou 6, YLY6) rice cultivars across farmers' practice (FP) and SRIP treatments in central China in 2014 and 2015. Compared with FP, reducing N input by 50.0% (SRIPN) caused maximum yield reduction of 12.8%, while reducing planting density by 33.3% (SRIPD) did not affect grain yield as much as SRIPN. The large reduction in resource inputs did not cause substantial yield losses because of compensation among yield components. The average yield of YLY6 was 1.38 t ha−1 higher than that of HHZ. Higher yield of YLY6 was mainly resulted from longer total growth duration, and higher total dry weight, leaf area index, and 1000-grain weight than HHZ. More importantly, the yield advantage of YLY6 over HHZ was greater in SRIP than in FP, which implies that YLY6 was less sensitive to reduced inputs than HHZ. Overall, the yield stability of YLY6 was significantly higher than that of HHZ across the crop management treatments and years. These results suggest that hybrid rice is more suitable to simplified crop management practices with reduced inputs than inbred rice.