Technical Abstract: Recent innovations in tall fescue breeding and selection allow for the generation of dihaploid tall fescue lines. During the dihaploid generation process, two possible products can be generated. These being tall fescue hybrids generated from outcrossing and homozygous dihaploid tall fescue lines. As a means to rapidly differentiate between these two types of products, an automated Advanced Analytical CE capillary electrophoresis system was employed to evaluate various EST-SSR marker profiles for selected individuals. Thirty lines were submitted for the analysis which included two well characterized open-pollinated checks. Of these, twenty individuals were identified as dihaploid and eight were identified as outcrosses hybrids. The 2-5 bp fragment separation resolution for smaller EST-SSR fragments (100-250bp) was found to provide an acceptable level for discriminating between dihaploid and outcross lines. The use of a an automated capillary electrophoresis device can be efficiently utilized to enhance selection of tall fescue dihaploid lines. The analysis also provided valuable information with regard to the viability and receptivity of embryos to fertilization by cross or open-pollination and the necessity for plant isolation during the dihaploid generation process.