There are abundant examples of the utility of landraces and wild relatives as potential sources of new genes and alleles for crop breeding. In crops like barley, the genetic variability of landraces was not fully exploited at the beginning of modern breeding. Linkage drag is one major issue when considering introgression from exotic sources. Introgression of new alleles into elite cultivars is done more effectively from landraces than from wild relatives, as they are genetically closer. For these reasons, barley landraces should be thoroughly mined for new genes or alleles. The Spanish Barley Core Collection (SBCC) was conceived as a resource for research, and was assembled as a representative sample of the genetic variability present in the collection of over 2000 accessions held at the National repository for plant genetic resources (CRF-INIA). The objective of this study was to carry out a preliminary survey of the potential of the SBCC as a source of disease resistance genes or alleles, and to assess the possibility of detecting disease resistance QTLs via association mapping. In a companion paper (Yahiaoui et al., this volume), we tested the feasibility of carrying out association analysis for agronomic and morphological data.