Oat production in Minnesota

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New DArT markers for oat provide enhanced map coverage and global germplasm characterization

BACKGROUND: Genomic discovery in oat and its application to oat improvement have been hindered by a lack of genetic markers common to different genetic maps, and by the difficulty of conducting whole-genome analysis using high-throughput markers. This study was intended to develop, characterize, and apply a large set of oat genetic markers based on Diversity Array Technology (DArT). RESULTS: Approximately 19,000 genomic clones were isolated from complexity-reduced genomic representations of pooled DNA samples from 60 oat varieties of global origin. These were screened on three discovery arrays, with more than 2000 polymorphic markers being identified for use in this study, and approximately 2700 potentially polymorphic markers being identified for use in future studies. DNA sequence was obtained for 2573 clones and assembled into a non-redundant set of 1770 contigs and singletons. Of these, 705 showed highly significant (Expectation < 10E-10) BLAST similarity to gene sequences in public databases. Based on marker scores in 80 recombinant inbred lines, 1010 new DArT markers were used to saturate and improve the 'Kanota' × 'Ogle' genetic map. DArT markers provided map coverage approximately equivalent to existing markers. After binning markers from similar clones, as well as those with 99% scoring similarity, a set of 1295 non-redundant markers was used to analyze genetic diversity in 182 accessions of cultivated oat of worldwide origin. Results of this analysis confirmed that major clusters of oat diversity are related to spring vs. winter type, and to the presence of major breeding programs within geographical regions. Secondary clusters revealed groups that were often related to known pedigree structure. CONCLUSION: These markers will provide a solid basis for future efforts in genomic discovery, comparative mapping, and the generation of an oat consensus map. They will also provide new opportunities for directed breeding of superior oat varieties, and guidance in the maintenance of oat genetic diversity

Selection for partial resistance to oat crown rust in two recurrent selection populations: a path analysis

Crown rust (Puccinia coronata) is the most devastating and widespread disease on oats (Avena sativa). Race specific resistance, conferring complete resistance, has proven to be nondurable. Partial resistance has been proposed as a more durable type of resistance. The objective of this work, which is part of a thesis (Pacheco, 2004), was to determine through path analysis which traits were associated with partial resistance to oat crown rust selected in two recurrent selection populations. The two studied recurrent selection populations are subpopulations derived from the same base population, started in 1968 as a closed system selected for grain yield. A subpopulation was opened twice, in 1988-1989, with introgression of four oat cultivars. Since 1996, six cycles of selection for partial resistance to crown rust were applied on the closed system rust and four cycles on the three-way cross system - rust . All selected parents from each population, and each selection cycle, were evaluated in two locations, in hill plots, sown with 30 seeds/hill, replicated four times. Path coefficient analysis revealed that later heading dates were associated with greater partial resistance, especially in the closed system, mainly because of an indirect effect via a longer time to reach 33% of maximum severity (T33-maxsev), which tended to reduce the maximum severity. In the three-way cross system later heading dates also resulted in longer epidemic durations, leading to an increase in the amount of disease in the end of the rust epidemic comparing to genotypes with shorter epidemic duration. Plant height seems to not be associated with partial resistance. Selection of partial resistant genotypes should be based on both AUDPC and maximum severity values and very late flowering genotypes should be avoided. Pacheco, M.T. 2004. Selection for resistance to oat crown rust in two recurrent selection populations. 133 p. Ph.D. Thesis.vokMyynti MTT tietopalvelu

Plant growth regulator and daylength effects on preanthesis main shoot and tiller growth in conventional and dwarf oat

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