Changing maize hybrids helps adapt to climate change in Northeast China: revealed by field experiment and crop modelling

Adopting new cultivars is an effective strategy to partially offset the negative effects of climate change on crop yields. We integrated the regional agro-meteorological observations, site-level field experiment data, and a process-based crop model to assess the effects of maize hybrid management on grain yield at meteorological sites across Northeast China. On a regional scale, for per 1 celcius increase in Tmin (Tmax) at the agro-meteorological stations, the length of the entire actual growing period for maize was shortened by 3.6 (2.3) days per year. Without changing maize hybrids, maize grain yield could be in jeopardy. Adopting hybrids with relatively longer growing period could take full advantage of the regional warming trend and hence improve the maize grain yield. In this study, we found that adopting novel hybrids (bred through trait selection and propagation during the past four decades) could improve maize grain yield in Northeast China. This conclusion was supported by the two-year field experiment that used nine prevailing newly-bred hybrids and the well-validated crop modeling at 74 locations covering a 60-year period (from 1961 to 2020). Compared with using the same hybrid, changing hybrid adapted the maize production to climate change in Northeast China; and the regional maize grain yield was increased by 5.4%, 7.4%, 6.8%, and 10.3%, respectively, due to changes in, respectively, solar radiation, Tmax, Tmin, and precipitation. The improvement in maize grain yield became more evident as latitude increased, especially at locations to the north of 42.5oN. In the future, changing hybrid may increase the region-simulated maize grain yield by 6.2 and 7.2% under the scenarios of SSP-126 and SSP-585, respectively. In sum, adopting newly-bred maize hybrids, especially those with relatively long growing periods, would be an effective measure to adapt regional maize production to climate change in Northeast China.