Research direction: Molecular identification of maize germplasm resources, a core technology in maize breeding. Background: In the past decade, China has cultivated many high stem, large panicle, sparse and late maturing varieties with high yield per plant, but the actual yield in production is relatively low. If maize continues to produce high yield, the only way out is through high density. More than 6000 plants/mu. However, the bottlenecks limiting density are plant height, density tolerance (low light tolerance), and plant leaf type. For more than a decade, our company has introduced a large number of excellent and characteristic (dwarf) maize germplasm resources from abroad, planted at a density of 7000 plants per acre, and achieved significantly higher yields than the control, laying the foundation for this study. Expected target technical parameter assessment objective: 1. Cultivate 6 backbone inbred lines. 2. Create 20 new maize breeding materials with excellent traits such as dwarf, density tolerance, lodging resistance, disease resistance, and high yield. 3. Publish 1 related paper. We have now met the conditions (equipment/personnel/funds) by introducing a large number of excellent and characteristic (dwarf) maize germplasm resources from abroad. We have bred 22 dominant dwarf inbred lines (1.5 meters), 12 non genetically modified insect resistant inbred lines, and 6 hybrid combinations of maize below 2 meters. Planting at a density of 7000 plants per acre, the yield is significantly higher than the control, laying the foundation for this study. Seven researchers participated in the project, including two doctoral students. I have a solid foundation and practical work ability, and the funds (200000 yuan) have been in place. Ensure the completion of the task.