No abstract

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).

Molecular mapping of cultivated oats was conducted to update the previous reference map constructed using a recombinant inbred (RI) population derived from Avena byzantina C. Koch cv. Kanota x Avena sativa L. cv. Ogle. In the current work, 607 new markers were scored, many on a larger set of RI lines (133 vs. 71) than previously reported. A robust, updated framework map was developed to resolve linkage associations among 286 markers. The remaining 880 markers were placed individually within the most likely framework interval using chi2 tests. This molecular framework incorporates and builds on previous studies, including physical mapping and linkage mapping in additional oat populations. The resulting map provides a common tool for use by oat researchers concerned with structural genomics, functional genomics, and molecular breeding.

All 10 chromosomes of maize (Zea mays, 2n ϭ 2x ϭ 20) were recovered as single additions to the haploid complement of oat (Avena sativa, 2n ϭ 6x ϭ 42) among F 1 plants generated from crosses involving three different lines of maize to eight different lines of oat. In vitro rescue culture of more than 4,300 immature F 1 embryos resulted in a germination frequency of 11% with recovery of 379 F 1 plantlets (8.7%) of moderately vigorous growth. Some F 1 plants were sectored with distinct chromosome constitutions among tillers of the same plant and also between root and shoot cells. Meiotic restitution facilitated development of un-reduced gametes in the F 1. Self-pollination of these partially fertile F 1 plants resulted in disomic additions (2n ϭ 6x ϩ 2 ϭ 44) for maize chromosomes 1, 2, 3, 4, 6, 7, and 9. Maize chromosome 8 was recovered as a monosomic addition (2n ϭ 6x ϩ 1 ϭ 43). Monosomic additions for maize chromosomes 5 and 10 to a haploid complement of oat (n ϭ 3x ϩ 1 ϭ 22) were recovered several times among the F 1 plants. Although partially fertile, these chromosome 5 and 10 addition plants have not yet transmitted the added maize chromosome to F 2 offspring. We discuss the development and general utility of this set of oat-maize addition lines as a novel tool for maize genomics and genetics.