The aim of this study was to investigate whether key agronomic traits of tall fescue synthetic progeny could be improved by using genetically diverse parents selected from a large breeding pool. Two polycrosses of six parental plants each with contrasting levels of diversity based on phenotypic traits and two polycrosses of six parental plants with contrasting levels of molecular marker diversity as determined using EST-SSR markers were composed. A fifth polycross was composed using six genotypes with highest general combining ability. Syn1 and Syn2 progeny from parents with high general combining ability generally showed lower values for most traits investigated when compared to progenies derived from other polycrosses. Progeny from parents selected for high molecular genetic diversity showed comparable or higher values than the other progenies for all traits investigated. The assessment of phenotypic and molecular genetic diversity of the five population progenies showed high congruence with the diversity observed among the respective parental plants. Our results demonstrate that EST-SSR markers provide a reliable means to predict genetic diversity in progenies which may allow for efficiently selecting parental genotypes and enhancing tall fescue breeding programs. Key words: tall fescue, polycross breeding, synthetic cultivar, molecular markers, phenotypic traits.
