the "state of the art" in the genetic improvement of traditional forages plants in argentina, its diffusion and impact, will be based on analysis of two large areas, quantitative genetics and plant breeding. it is clear that to drive plant breeding programs is necessary to know and understand concepts of plant genetics and relationships between this and other agronomy disciplines, particularly animal production. the traditional forage species selection was based on the introduction of collections and using the mass selection methods in some of these populations. estimation and interpretation of heritability has presented numerous challenges to researchers in population genetics and quantitative genetics. these two disciplines of genetics, along with biometrics, allowed a development more precise of plant breeding methods. this paper illustrates about the development of cultivars of two forage species: tall fescue [lolium arundinaceum (schreb.)] darbysh. = festuca_arundinacea_schreb.] and prairie grass (bromus. catharticus vahl.). there is a need to assess in detail the objectives and characteristics of the species and its evaluation in our area and in recent years, which was real progress on the transfer of knowledge, application to the "art" of plant-breeding and developing of cultivars, without neglecting the last link in the goal to achieve: its adoption in the productive sector. with the possibility of developing new approach to breeding and to speculate about future applications of molecular tools, it is clear that improved cultivars will have a major role in the future.