Effects of climate change on the yield potentials and resource use efficiencies of mid-season indica rice cultivars in Eastern China

Abstract

Abstract 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 ℃ 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.