RESEARCH ARTICLE Structural patterns and genetic diversity among oat (Avena) landraces assessed by microsatellite markers and morphological analysis Nikolaos Nikoloudakis . Konstantinos Bladenopoulos . Andreas Katsiotis Received: 17 March 2015 / Accepted: 29 June 2015 Ó Springer Science+Business Media Dordrecht 2015 Abstract As a counterweight to genetic erosion, landraces could become important germplasm resources for breeding. In the present study the genetic diversity of 62 Greek and Eastern European oat accessions (seven cultivars and 55 common and red oat landraces collected from 1904 to 1960) was studied using simple sequence repeats and 31 mor- phological descriptors. High levels of polymorphism were detected and 209 distinctive alleles were iden- tified; on average 14.65 alleles per primer. Both, the principal component analysis derived from the mor- phological data, and the unweighted pair group method with arithmetic mean from the molecular analysis clustered the oat genotypes according to their type (common and red oats). In addition, the analysis of molecular variation showed that there were note- worthy differences within designated geographic regions. Moreover, a more discrete subpopulation structure was identified based on allele frequency using a Bayesian clustering approach. A clear distinc- tion was evident among the red and common oats suggesting that they should be considered as separate species. Keywords Avena. byzantina Á A. sativa Á Morphological traits Á Simple sequence repeats (SSR) Introduction Oat is a western Mediterranean cereal (Loskutov 2008) with a fairly recent agricultural history, since its cultivation began a few millennia later than the one of wheat and barley, and archaeological records docu- mented oats—along with rye—as weed contaminants (Newton et al. 2010). In more recent years, this grain was mainly used as hay or silage; but its’ main utilization has been as a livestock feed. Nowadays, oat is considered as one of the most important cereal crops in the world (being widely used for human consump- tion as a source of valuable nutrients; Boczkowska and Tarczyk 2013) and has received considerable attention with respect to collection and conservation. More than 200,000 accessions of wild and culti- vated Avena species are stored in seed gene banks worldwide (Diederichsen 2008). Landraces in partic- ular, made a significant contribution to the current oat germplasm, since several modern varieties trace their origin back to a restricted number of them. Different Electronic supplementary material The online version of this article (doi:10.1007/s10722-015-0284-9) contains supple- mentary material, which is available to authorized users. N. Nikoloudakis Á A. Katsiotis (&) Department of Agricultural Science, Biotechnology and FoodScience, Cyprus University of Technology, Athinon and Anexartisias 57, 3603 Limassol, Cyprus e-mail: andreas.katsiotis@cut.ac.cy K. Bladenopoulos Cereals Institute, National Agricultural Research Foundation, 570 01 Thermi, Greece 123 Genet Resour Crop Evol DOI 10.1007/s10722-015-0284-9