Six hundred thirty five oat (Avena sativa L.) lines and 4561 single-nucleotide polymorphism (SNP) loci were used to evaluate population structure, linkage disequilibrium (LD), and genotypephenotype association with heading date. The first five principal components (PCs) accounted for 25.3% of genetic variation. Neither the eigenvalues of the first 25 PCs nor the cross-validation errors from K = 1 to 20 model-based analyses suggested a structured population. However, the PC and K = 2 model-based analyses supported clustering of lines on spring oat vs. southern United States origin, accounting for 16% of genetic variation (p < 0.0001). Single-locus F-statistic (F ST ) in the highest 1% of the distribution suggested linkage groups that may be differentiated between the two population subgroups. Population structure and kinship-corrected LD of r 2 = 0.10 was observed at an average pairwise distance of 0.44 cM (0.71 and 2.64 cM within spring and southern oat, respectively). On most linkage groups LD decay was slower within southern lines than within the spring lines. A notable exception was found on linkage group Mrg28, where LD decay was substantially slower in the spring subpopulation. It is speculated that this may be caused by a heterogeneous translocation event on this chromosome. Association with heading date was most consistent across location-years on linkage groups Mrg02, Mrg12, Mrg13, and Mrg24. Core Ideas• An oat association-mapping panel contributed by active breeding programs worldwide.• Characterized population structure and found subdivisions related to adaptation• Characterized genome-wide and chromosomespecific linkage disequilibrium• Performed association-mapping and post hoc modeling of heading date• Found several consistently associated QTL

Marshall, A. H., Cowan, A. A., Edwards, S., Griffiths, I. M., Howarth, C. J., Langdon, T., White, E. (2013). Crops that feed the world 9. Oats- a cereal crop for human and livestock feed with industrial applications. Food Security, 5 (1), 13-33.Oats are a low input cereal widely grown across the world as both a grain and forage crop. Significant areas of production are in Northern Europe and North America and also in China and Australia. Although a traditional crop in many countries, in the last 50 years there has been a significant shift in oat production as a consequence of changing agricultural production and competition from other cereal crops. Oats are of significant economic importance for human consumption, for livestock feed and increasingly as a source of high value compounds with industrial applications as a consequence of the many unique properties of the oat grain. Traditional use in human diets in many countries has been boosted by the recent recognition of oats as a health food. This is attributed to the presence of ?-glucan, the major endospermic cell wall polysaccharide. As a result, there has been an increase in the use of oats and a broadening of oat based products. Increasing knowledge of the composition of the oat grain and its value for the various end-users is leading to new opportunities for the crop. While the value of oats as a break crop in cereal based rotations is widely recognised, maintaining the profitability of the crop whilst meeting the needs of end users is essential for future production. Opportunities exist for plant breeders and agronomists to introduce new oat varieties with tailored agronomic approaches to address this challenge and to ensure the sustainability of oats for the future.Peer reviewe

Sponsorhip: BBSRC RONO: BB/J004405/1; BB/H009582/1; BBS/E/W/10962A01CIn this study, genetic diversity among 177 oat (Avena sativa L.) accessions including both white and red oat landraces and 36 commercial cultivars was studied for simple sequence repeat (SSR) loci. Thirty-one genomic and expressed sequence tags (EST)-derived primer pairs were selected according to high polymorphism from an initial 66 SSR batch. Markers revealed a high level of polymorphism, detecting a total of 454 alleles. The average gene diversity for the whole sample was 0.29. Genetic similarity, calculated using the Dice coefficient, was used for cluster analysis, and principal component analysis was also applied. In addition, population structure using a Bayesian clustering approach identified discrete subpopulation based on allele frequency and showed similar clustering of oat genotypes in four groups. Accessions could be classified into four main clusters that clearly separated the commercial cultivars, the red oat landraces and two clusters of white oat landraces. Cultivars showed less diversity than the landraces indicating a reduction of genetic diversity during breeding, whereas white oat landraces showed higher diversity than red ones. The average polymorphic information content of 0.80 for the SSR loci indicated the usefulness of many of the SSR for genotype identification. In particular, two markers, MAMA5 and AM04, with a total of 50 alleles and a high discrimination power (>0.90), were sufficient to discriminate among all commercial cultivars studied highlighting their potential use for variety identification.Peer reviewe