Utilization of exotic tropical and subtropical maize germplasm

Maize is the third most important crop in the world and China.The average of maize production area in China is 24 5 million ha;the average maize yield is 4 96 ton per ha China ranks the second in the world in terms of total maize area and production.The rate of maize yield growth has being declining due to narrow genetic background and limited new heterotic patterns since 1970s.The role of tropical and subtropical maize germplasm in maize improvement was discussed in this paper.It was concluded that the Chinese maize germplasm background should be broaden by using the tropical and subtropical maize germplasm.The new heterotic patterns should be developed and new hybrids with super heterosis could be bred,the methods of using tropical and subtropical maize germplasm were pointed out in this paper.