Improved polycross breeding of tall fescue through marker-based parental selection

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. Syn1 progeny of four polycrosses composed using six parental plants with contrasting levels of diversity based on phenotypic and expressed sequence tag (EST)-simple sequence repeat (SSR) markers were investigated together with the progeny of a fifth polycross composed using six genotypes with highest general combining ability. Syn1 progeny from parents with high general combining ability generally showed lower values for most traits investigated when compared to progeny derived from other polycrosses. Progeny from parents selected for high molecular genetic diversity showed comparable or higher values than the other progeny for all traits investigated. The assessment of phenotypic and molecular genetic diversity of the five Syn1 populations showed high congruence with the diversity observed among the respective parental plants and decreased from parents to Syn1 as expected. Our results demonstrate that EST-SSR markers provide a reliable means to predict genetic diversity in Syn1 progeny that may allow for efficiently selecting parental genotypes and enhancing tall fescue breeding programmes.