Dynamics of high-yielding maize genotypes under intensive management across multiple environments

The growing demand for food, fuel, and other agricultural products is reached to be met by increasing production on the land currently under cultivation. To tackle this challenge, we conducted 468 plots containing 263 maize hybrids during 2010-2021. Plots were divided into three yield bands: < 17.7, 17.7-21.0, and > 21.0 Mg/ha. The average yield was 19.2 Mg/ha, with a range of 9.8-24.9 Mg/ha. Dry matter (DM) accumulation and harvest index (HI) are key factors that determine the final grain yield. From < 17.7 Mg/ha to > 21.0 Mg/ha, mean yield increased by 40.8 %, dry matter (DM) accumulation, post-silking DM and HI increased by 13.2 %, 14.7 % and 10.4 %, respectively. Yield increased from the lowest to the highest yield band, the proportion of dry grains weight to post-silking DM and grain leaf ratio increased, while the remobilization efficiency of pre-silking DM decreased. The contribution of pre-silking DM to yield decreased as yield increased, whereas the contributions of post-silking DM to yield increased. When the yield was > 21.0 Mg/ha, the proportion of pre- and post-silking DM was about 4:6. HI increased with the increase of yield. When the yield was >= 18.08 Mg/ha, the HI was stable at 0.53. In conclusion, under high plant density conditions, increased yield requires higher post-silking DM and HI. Our results are crucial to identify methods of enhancing yield at the population level and meet the food demands of the growing human population.