Use of SSR data to determine relationships and potential heterotic groupings within medium to late maturing Iranian maize inbred lines

Information on germplasm diversity and relationships among elite materials is fundamentally important in crop improvement. The main objectives of our study were to: (1) determine the level of genetic diversity within and relationships among the most commonly used medium to late maturing Iranian maize inbred lines using simple sequence repeat (SSR) markers, and to (2) suggest heterotic groups among the lines using genetic distance as measured by the SSR markers. Fifty-six inbred lines, which are the most commonly used in maize breeding programs in Iran, and two lines from CIMMYT, Mexico (used as checks) were fingerprinted with 46 SSR markers. A total of 225 alleles were detected. The UPGMA clustering grouped the Iranian inbreds into four clusters (in addition to one group which included only the CIMMYT control lines), which were consistent with the pedigrees or known information about source materials. The highest distance was found between the cluster of Reid Yellow Dent related lines and the cluster of Lancaster Sure Crop related lines, and this pattern has produced some of the highest yielding hybrids in Iran. Other heterotic patterns based on the SSR markers are suggested, but must be field tested to confirm what appears to be promising alternative heterotic patterns. (c) 2005 Elsevier B.V. All rights reserved.