Phosphorus Accumulation Characteristics of Medium-maturity Yongyou japonica/indica Hybrid Rice After Transplanting and Its Modeling

【Objective】This study was conducted to quantitatively describe the dynamic changes of phosphorus accumulation of medium-maturity japonica/indica hybrids (MJIH) after transplanting based on simulation equations. 【Method】Yongyou 2640 and Yongyou 1640 were used as the test materials, and the japonica conventional rice (JC) cultivar Yangjing 4038 and Yangjing 4227, and indica hybrid rice (IH) Xinliangyou 6380 and Yangliangyou 6 were used as controls to study phosphorus accumulation characteristics after transplanting, and the differences in phosphorus uptake and utilization characteristics after transplanting among different rice types were compared. 【Result】Grain yield and total phosphorus accumulation at maturity of MJIH were both significantly higher than JC and IH. Compared with JC and IH, MJIH had higher grain phosphorus accumulation, while lower phosphorus grain productivity. MJIH showed lower phosphorus translocation from leaf after heading compared with JC and IH, and its phosphorus translocation from stem after heading fell in between. Gompertz equation was used to simulate phosphorus accumulation after transplanting of MJIH, while logistic equations for JC and IH. MJIH showed higher maximum nitrogen accumulation rate than JC and IH. The maximum phosphorus accumulation rate of MJIH was observed at 50－52 d after transplanting, 59－60 d after transplanting for JC, and 61－63 d for IH, respectively. Compared with JC and IH, MJIH had higher phosphorus accumulation at the middle and late stages, while lower phosphorus accumulation at the early stage. The higher phosphorus accumulation at the middle and late stages of MJIH was attributed to its longer duration and higher accumulation rate, relative to JC and IH. 【Conclusion】Our results indicated that compared with JC and IH, MJIH had superior grain yield and total phosphorus accumulation. The advantage in phosphorus accumulation of MIJH over JC and IH was seen at the middle and late stages, mainly owing to its longer duration and higher accumulation rate.