A selection technology for density tolerance and high resistance was proposed in this project, and then was used to create Zhongdan 808 and Zhongdan 909 and established an efficient system of seed production and promotion. The cultivated area of these hybrids was about 6,693,333.3 hm2 by 2018, which contributed to an increase of 5.31 billion kilograms of grain and significant social and economic benefits.

The field display of maize hybrids for Zhongdan 808 and Zhongdan 909