Crown rust (Puccinia coronata Cor. Var. avenae R.P. Fraser & Ledingham) is an important disease of oat (Avena sativa L.) in most oat production areas throughout the world. Single gene hypersensitive resistance has been repeatedly overcome within several years of wide deployment in oat cultivars by shifts in the pathogen's diverse virulence genes. Slow rusting, characterized by low receptivity, delayed latent period, and reduced fungal growth, is proposed to be a durable form of resistance, less prone to race selectivity and thought to be conditioned by a number of genes. Oat inbred line P8669 was crossed to the slow rusting inbred line P94163 that has slow crown rusting derived from A. sterilis L A recombinant inbred (RI) population of 192 lines was developed from this cross by single seed descent and progeny of single F9 plants were tested in replicated plots in the field at West Lafayette, Indiana in 2004 - 2006 and in a greenhouse in 2006. Continuous variation for characterization of slow rusting was identified in the population and there was consistency across field and greenhouse tests. QTL's associated with crown rust resistance will be located and mapped.