Comparisons of grain yield and nutrient accumulation and translocation in high-yielding japonica/indica hybrids, indica hybrids, and japonica conventional varieties

In China, high-yielding rice varieties called “super rice” have been developed among indica hybrid (IHS), japonica conventional (JCS), and japonica/indica hybrid (JIHS), but yield differences among these three rice groups have not been documented. In this study, four IHS varieties, four JCS varieties, and four JIHS varieties were compared for their yield formation including utilization of nitrogen (N), phosphorus (P), and potassium (K), in field experiments in 2013 and 2014 at Ningbo, Zhejiang, China. The average grain yield of JIHS across varieties and years was 12.4 t ha−1, 11.3% and 15.3% higher than that of JCS and IHS, respectively. JIHS showed more spikelets per panicle and longer total growth duration compared with JCS and IHS. Compared with JCS and IHS, JIHS showed higher dry matter accumulation after stem elongation and higher leaf area index at heading and maturity stages. The higher grain yield produced by JIHS was accompanied by a higher total N, P, and K accumulation compared with JCS and IHS. Compared with JCS and IHS, JIHS showed higher N translocation from the stem and lower P translocation from the leaf during the period from heading to maturity.