Global climate change affects crop yields and endangers food security. High yielding rice varieties adapted to climatic changes is a key breeding objective. However, little is known regarding the impact of climate change on the yield potentials and resource utilization efficiencies of modern rice cultivars in Eastern China. Using two-year field experiment, we investigated the biomass, nitrogen (N) uptake, and yield in relation to climatic resource use efficiencies of eight representative Chinese mid-season indica rice (Oryza sativa L.) cultivars grown in the Middle Lower Yangtze Area over the last fifty years. The yield potential of rice from 1961-2015 was simulated using the ORYZA (v3) model. The total thermal time (growing degree days) increased at a rate of 3.3 degrees C yr(-1), while sunshine hours decreased at a rate of 2.4 h yr(-1) over the past five decades during growth period. Compared with the average potential yield from 1961 to 1975, an average 5.65 % of reduction occurred across different cultivars from 2001 to 2015. However, the rice potential yield increased by 52.0 kg ha(-1) yr(-1) in the released cultivars with increasing years of release. The use efficiencies of sunshine hours and thermal time for the cultivar Yangliangyou6 released in 2001 increased by 68.5 % and 59.5 % compared with the cultivar Shenglixian released in 1938. The increase of potential yield in the released cultivar Yangliangyou6 was attributed to increase utilization efficiency of radiation. Modern cultivars (semi-dwarf and super rice) maintained greater leaf area index (LAI) during the filling period without modification in photosynthetic rate. Besides, the decrease in grain N concentration contributed to stay-green characteristic and to the efficient use of N in modern cultivars. Thus, modern indica rice cultivars tolerate the adverse climatic changes by optimizing plant productivity and increasing resource utilization efficiencies.
Zhang, YK; Zhu, D; Zhang, YP; Xiang, J; Wang, YL; Zhu, DF; Wang, L; Chen, HZ
Effects of climate change on the yield potentials and resource use efficiencies of mid-season indica rice cultivars in Eastern China
Field Crops Research