Assessing the genetic diversity of Bulgarian maize germplasm using microsatellite markers

Maize (Zea mays L.) is traditionally an important crop for Bulgaria. As a part of European Corn belt, Bulgaria has a rich collection of local varieties and exotic germplasm. The gene bank collections (IPGR-Sadovo and MRI-Kneja) contain more than 4500 accessions possessing valuable agronomic traits. In addition several Synthetic populations were initiated to develop new Bulgarian maize germplasm and inbreds with high general and specific combining ability for use in the breeding programs that are focused on hybrids with high heterosis effect. For rational use of maize genetic resources and selection of parental genotypes for hybridization, a program for characterization and assessment of genetic diversity in Bulgarian maize germplasm collections, and creation of molecular marker database was initiated. Genetic diversity was measured with SSR analysis. The set of SSR markers detected in average 9.1 different allelic variants per locus for Bulgarian and US inbreds, with mean expected heterozygosity (He)=0.713 in Bulgarian, and 0.693 in US inbreds. Cluster analysis indicated that almost all of the inbreds could be distinguished from each other and Bulgarian inbreds were present in all clusters formed. In this study SSR markers proved to be fast and powerful tool for genotyping and discrimination of closely related inbreds.