Analysis of Maize Heterotic Groups and Patterns During Past Decade in China

In this investigation, maize heterotic groups and patterns were analyzed based on theplanting areas from 1992 to 2001 using 84 parent lines of 71 widely extended hybrids andclassification results by SSR markers, in which these lines were assigned into sevenheterotic groups based on Ni-LIs genetic distances. The results indicated that acertain extent change for major heterotic groups of maize took place during past decadein China. The major heterotic groups were Lancaster, Reid, Tang SPT, Zi330 and E28 in theearly 1990s, while they became Reid, Tem-tropicⅠ, Zi330, Tang SPT and Lancaster in theearly 21st century. Tem-tropicⅠwas a new heterotic group, which contained tropic maizegermplasm. The changes for heterotic patterns also occurred. Some new heterotic patternscombining with Tem-tropicⅠappeared, such as ReidTem-tropicⅠ, Zi330Tem-tropicⅠ,Tang SPTTem-tropicⅠ, etc.. Another change was the order of heterotic patterns. In theearly and middle 1990s, the top five heterotic patterns were ReidTang SPT, Zi330Lancaster, LancasterTang SPT, LancasterE28 and ReidZi330, while they became ReidTem-tropicⅠ, ReidZi330, ReidTang SPT, Zi330Tem-tropicⅠand LancasterTang SPT inthe early 21 century. ReidTem-tropicⅠand Zi330Tem-tropicⅠwere laid on the firstand forth Chinese heterotic patterns respectively in 2001. These results providedsignificant information to understand the maize heterotic groups and patterns in Chinaat molecular level.