167 maize hybrids have been approved by Shandong Provincial Committee of Crop Variety Certification since 1982.This article analyzed 125 ordinary maize varieties.The results showed that in 1980s the core germplasms were Lancaster,Sipingtou and Reid,the main heterotic models were Sipingtou×Reid and Lancaster×Local germplasm.The main lines were Huangzaosi and Mo17.Shandong Province took the lead in the use of foreign breeding materials,such as U8112.In 1990s,the germplasm background of maize hybrids was narro...