| Abstract: | In this investigation,maize heterotic groups and patterns were analyzed based on the planting areas from 1992 to 2001 using 84 parent lines of 71 widely extended hybrids and classification results by SSR markers,in which these lines were assigned into seven heterotic groups based on Ni-LI's genetic distances.The results indicated that a certain extent change for major heterotic groups of maize took place during past decade in China.The majorheterotic groups were Lancaster,Reid,Tang SPT,Zi330 and E28 in the early 1990s,while they became Reid,Tem-tropic Ⅰ,Zi330,Tang SPT and Lancaster in the early 21st century.Tem-tropic Ⅰ was a new heterotic group,which contained tropic maize germplasm.The changes for heterotic patterns also occurred.Some new heterotic patterns combining with Tem-tropic Ⅰ appeared,such as Reid × Tam-tropic Ⅰ,Zi330 × Tem-tropic Ⅰ,Tang SPT × Tem-tropic Ⅰ,etc..Another change was the order of heterotic patterns.In the early and middle 1990s,the top five heterotic patterns were Reid×Tang SPT,Zi330 ×Lancaster,Lancaster× Tang SPT,Lancaster × E28 and Reid × Zi330,while they became Reid × Temtropic Ⅰ,Reid×Zi330,Reid×Tang SPT,Zi330 ×Tem-tropic Ⅰ and Lancaster×Tang SPT in the early 21 century.Reid×Tem-tropic Ⅰ and Zi330 × Tem-tropic Ⅰ were laid on the first and forth Chinese heterotic patterns respectively in 2001.These results provided significant information to understand the maize heterotic groups and patterns in China at molecular level. |
