Abstract: 【Objcetive】The purpose of this study is to analyze the heterotic pattern of maize hybrids used in Henan Province. 【Method】Simple sequence repeat (SSR) was used to study genetic diversity of the parents of some maize hybrids approved in China′s Henan Province and some other inbred lines. A total of 143 SSR primer pairs were tested, from which 95 primer pairs that evenly distributed on maize genome were selected for genotyping the inbred lines. Cluster analysis of the inbred lines was performed by using UPGMA method. The heterotic patterns of hybrids approved in Henan Province as well as introduced ones were also analyzed based on the planting areas of the hybrids in Henan Province from 1981 to 2003. 【Result】 The results showed that: (1) most of the inbred lines used for making hybrids approved in Henan could be divided into six groups, i.e. Reid, Tem-tropic, SiPT, LvDHG, Lancaster and Synthetic, based on Nei-Li's genetic distances, which agreed with the result from pedigree analysis; (2) there were 12 heterotic patterns employed for making of hybrids widely used in Henan for maize cultivation, among which Reid × SiPT and Lan × LvDHG were prominent patterns. The hybrids from the two patterns occupied 47 % of total cultivation in Henan Province, among which 26.47% was for Reid × SiPT and 20.62% for Lan × LvDHG. Other patterns like Reid × LvDHG was 9.41% and Tem-tropic × others (including Synthetic and Reid) 9.07%. The later is a new pattern with an increasing utilization and is worthwhile to be exploited. 【Conclusion】Of the 12 heterotic patterns, Reid × SiPT and Lan × LvDHG were mainly used ,which occupied about a half of the total planting areas in Henan in the past 23 years.

Key words: Maize (Zea mays L.), Inbred line, Molecular marker, Heterotic group, Heterotic pattern