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Introduction: Oat (Avena sativa L.) is an important cereal crop grown worldwide for grain and forage, owing to its high adaptability to diverse environments. However, the genetic and genomics research of oat is lagging behind that of other staple cereal crops. Methods: In this study, a collection of 288 oat lines originating worldwide was evaluated using 2,213 single nucleotide polymorphism (SNP) markers obtained from an oat iSelect 6K-beadchip array to study its genetic diversity, population structure, and linkage disequilibrium (LD) as well as the genotype-phenotype association for hullessness and lemma color. Results: The average gene diversity and polymorphic information content (PIC) were 0.324 and 0.262, respectively. The first three principal components (PCs) accounted for 30.33% of the genetic variation, indicating that the population structure of this panel of oat lines was stronger than that reported in most previous studies. In addition, accessions could be classified into two subpopulations using a Bayesian clustering approach, and the clustering pattern of accessions was closely associated with their region of origin. Additionally, evaluation of LD decay using 2,143 mapped markers revealed that the intrachromosomal whole-genome LD decayed rapidly to a critical r² value of 0.156 for marker pairs separated by a genetic distance of 1.41 cM. Genome-wide association study (GWAS) detected six significant associations with the hullessness trait. Four of these six markers were located on the Mrg21 linkage group between 194.0 and 205.7 cM, while the other two significant markers mapped to Mrg05 and Mrg09. Three significant SNPs, showing strong association with lemma color, were located on linkage groups Mrg17, Mrg18, and Mrg20. Discussion: Our results discerned relevant patterns of genetic diversity, population structure, and LD among members of a worldwide collection of oat landraces and cultivars proposed to be 'typical' of the Qinghai-Tibetan Plateau. These results have important implications for further studies on association mapping and practical breeding in high-altitude oat. [ABSTRACT FROM AUTHOR]

The white-oat cultivar Barbarasul was developed by the Universidade Federal de Pelotas. It resulted from across between UPF18 and CTC5. It is adapted to the southern region of Brazil, with excellent grain yield potential, shortstature and high lodging tolerance.

O aumento da utilização dos grãos de aveia na alimentação humana tem estimulado os melhoristas a selecionar genótipos com alta qualidade de grãos. O presente trabalho foi realizado com o objetivo de identificar e caracterizar a variabilidade genética para o caráter teor de proteína bruta de grãos em genótipos cultivados de aveia, introduções silvestres de A. fatua L., A. sterilis L. e em populações híbridas de A. sativa L. x A. sterilis L. Os resultados revelaram uma ampla variabilidade genética para o caráter dentro dos grupos estudados. As diferenças observadas entre os genótipos cultivados parecem ocorrer devido a constituição genotípica diferenciada. O grupo silvestre de A. sterilis L. foi, em média, superior aos demais, sendo que a introdução I-325 se destacou pelo alto teor de proteína. O comportamento similar entre as introduções de A. fatua L. pode ser atribuído a coleta de introduções de apenas uma região, o que reduziu a variabilidade genética. Foram encontrados híbridos artificiais entre A. sativa L. x A. sterilis L. com alto teor de proteína e características desejáveis do grupo cultivado.The increased use of oat grains as human food has stimulated plant breeders to select genotypes with high grain quality. This work aimed to identify and characterize genetic variability for total grain protein in cultivated oat and introductions of A. fatua L., A. sterilis L. and hybrid populations from A. sativa L. x A. sterilis L.. The results showed a large genetic variability for the trait in the studied groups. Differences among cultivated oat genotypes may be attributed to different genetic constitution. A. sterilis L. group showed high protein content specially with the introduction of I-325. Genotypes from A. fatua L. showed similar low levels of protein probably because the narrow range of regions sampled in this study. Some hybrids from A. sativa L. x A. sterilis L. showed high protein content and acceptable agronomic traits.

Nove genótipos de aveia foram cultivados in vitro com o objetivo de formação de calos e posterior avaliação de embriogênese somática. Os calos foram testados em três protocolos (meio MS- MURASHIGE & SKOOG (1962) com diferentes dosagens de hormônios). Após um mês em meio de subcultivo, os calos foram avaliados quanto à porcentagem de embriogênese somática. Os protocolos testados revelaram respostas diferentes na indução de embrióides, proporcionando a escolha do que fosse mais adequado para esta função. No primeiro experimento não foi obtida diferença entre os genótipos, por outro lado, no experimento 2, a UFRGS 7 e UFRGS 8 possuíram médias significativamente maiores. A análise de covariância realizada com o objetivo de verificar se o tamanho de embrião estava envolvido na indução de embriogênese evidenciou que para alguns genótipos esta medida é importante.Nine oat genotypes were cultivated in vitro to evaluate callus initiaton and subsequent somatic embryogenesis. The immature embryo were submited to different protocola (MURASHIGE & SKOOG (1962) médium with differents hormones dosages). The protocols tested caused differences in somatic embryogenesis, and the best of them was selected to continue the research. After a month in subculture médium the cali were evaluated concerning embryoid porcentage, and showed differences according to genotype in experiment 2, UFRGS 7 and UFRGS 8 presented superior means. The covariance analysis revealed that in some genotypes this parameter is important.

Further understanding of the origin of cultivated oat would accelerate its genetic improvement. In particular, it would be useful to clarify which diploid progenitor contributed the D genome of this allohexaploid species. In this study, we demonstrate that the landmarks produced by fluorescence in situ hybridization (FISH) of species of Avena using probes derived from Avena sativa can be used to explore the origin of the D genome. Selected sets of probes were hybridized in several sequential experiments performed on exactly the same chromosome spreads, with multiple probes of cytological preparations. Probes pITS and A3-19 showed there might be a similar distribution of pITS between the Ac and D genomes. These results indicated that the Ac genome is closely related to the D genome, and that Avena canariensis (AcAc) could be the D-genome donor of cultivated oat. [ABSTRACT FROM AUTHOR]

We have sequenced, assembled, and characterized a set of complexity-reduced genomic clones derived from a chromosome 18D-specific library from hexaploid oat ( L.). Sequences from 314 clones were assembled into 99 contigs of identical or nearly identical sequence. The Censor tool was used to identify similarity to known and characterized repeat sequences in RepBase. Eight repeat classes were scattered throughout 50 contigs, with most repeats belonging to seven transposon and retrotransposon classes. After accounting for known repeats, additional matches to orthologous genes from other species were identified in 24 regions of 22 contigs, and an additional 47 regions matched genomic sequences from oat and other related species. These results provide information about the types and density of transposable elements in the oat genome, as well as the potential for identifying unique or chromosome-specific sequence elements in oat. Overall, these results predict a low success rate in identifying chromosome-specific coding regions in oat through chromosome isolation and genome complexity reduction. [ABSTRACT FROM AUTHOR]