Screening Wheat Cultivars with Genetic Similarity Using Molecular Markers

Wheat (Triticum aestivum L.) lines with similar traits are often found in the National Winter Wheat Regional Trials. Molecular markers have been regarded potential tools to efficiently and accurately identify wheat lines with genetic similarity. In this study, 681 wheat cultivars and lines were assessed using 63 genome-SSR, 21 EST-SSR, and 21 AFLP-SCAR markers. These markers were classified into core primer (21 pairs), first-grade standby primer (29 pairs), and second-grade standby primer (55 pairs). The cultivars and lines tested consisted of 134 released cultivars and 547 lines evaluated in the National Winter Wheat Regional Trials from 2005 to 2009. Cultivars and lines were primarily screened with the core primers, and those with similar fingerprint on 19–21 loci were further tested with the first-grade standby primers, and only the cultivars with genetic similarity (GS) larger than 0.90 were subjected to the detection by the second-grade standby primers. The molecular evaluation was based on at least 100 loci, and cultivars (lines) with total GS larger than 0.90 were suspected to be similar genotypes. These cultivars (lines) were continuously evaluated based on main morphological characteristics and agronomic traits before final decision. The GS of most cultivars and lines tested was larger than 0.90 according to molecular data. The molecular markers used in this study are effective in bulk screening similar cultivars and lines in wheat regional trials.