Heterotic groups of 29 inbreds were classified by using SSR markers in this study. The materials were included 4 temperate inbreds (B73, Mo17, Dan340 and Huangzaosi), which represented four main heterotic groups of Reid, Lancaster, Luda Red Cob, and Sipingtou in China, and 25 typical tropical inbreds, which were derived from 5 main tropical maize population and land races (Suwan 1, POP21, POP32, POP28 and Antigua). A total of 39 polymorphic SSR primers were selected from 70 SSR primers, which detected 127 a...