Submitted to: International Triticeae Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2009
Publication Date: June 5, 2009
Citation: Larson, S.R., Bushman, B.S., Mott, I.W., Wang, R., Jensen, K.B., Robins, J.G., Jones, T.A. 2009. USDA-ARS gene, genomic, and trait discovery research in perennial triticeae grasses. International Triticeae Symposium Proceedings, "6th International Triticeae Symposium" May 30 - June 5, 2009. in Kyoto, Japan. Technical Abstract: Long-term grass breeding efforts at the USDA-ARS Forage and Range Research Laboratory, traditionally focused on perennital Triticeae range grasses, have been expanded to include the development of molecular markers and genetic maps that can be used to investigate the genetic control of functionally important perennial grass traits. Genetic maps constructed from tetraploid interspecific hybrids of tall caespitose Leymus triticoides and relatively short rhizomatous Leymus cinereus have been used to identify chromosome regions associated with plant height, growth habit, flowering, seasonal biomass accumulation, seed shattering, seed germination, biotic and abiotic stress resistance, inflorescence traits related to seed production, and forage quality (fiber, protein, and mineral content). A total of 27,273 expressed gene sequence tag (EST) unigenes have been isolated and sequenced from Pseudoroegneria (8780), Elymus (7212), and Leymus (11281). Moreover, 1375 Pseudoroegneria, 442 Elymus, and 1798 Leymus EST simple sequence repeat (SSR) have been identified. PCR primers flanking these EST-SSRs have been tested for amplification and polymorphism on parental genotypes of existing or proposed new mapping populations. A total of 375 Leymus EST-SSR markers amplified one or more segregating markers in the Leymus mapping populations. These Leymus EST markers were used to align the Leymus linkage groups to the rice genome sequence and identify homoeologous groups relative to wheat, barley, and other Triticeae genomes. Bacterial artificial chromosome (BAC) genomic DNA libraries representing approximately 6.1 haploid genome equivalents of tetraploid Leymus have also developed and used to compare homoeologous genomic DNA sequences containing the rice lax and maize barrenstalk1 orthogene. Likewise, genetic maps are being constructed from interspecific hybrids of caespitose Elymus lanceolatus and rhizomatous Elymus wawawaiensis. Other traits of interest in the Elymus mapping populations include resistance to billbug (Parvulus parvula) feeding.