ARS | Publication request: Genome analysis of biomass heterosis and other functionally important perennial grass traits in hybrid leymus wildryes

Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: November 15, 2010
Publication Date: January 15, 2011
Citation: Larson, S.R., Jensen, K.B., Robins, J.G. 2011. Genome analysis of biomass heterosis and other functionally important perennial grass traits in hybrid leymus wildryes. Plant and Animal Genome XXIX Conference in San Diego, January 15-19, 2011.

Technical Abstract: Leymus is an allopolyploid perennial Triticeae genus with about 30 species that display remarkable adaptations to extreme cold, saline, and many other harsh growing environments throughout temperature regions of the World. Caespitose basin wildrye (Leymus cinereus) grows up to 3 m tall and is considered one of the largest native perennial grasses in western North America. Creeping wildrye (Leymus triticoides) is relatively short (about 1.5 m) but strongly rhizomatous grass that is particularly well adapted to saline habitats. Creeping x basin wildrye hybrids display a combination of tall plant height and rhizome proliferation traits that may contribute to superior biomass production. Thus, creeping x basin wildrye hybrids were used to make experimental genetic mapping populations, DNA libraries, and genetic maps with more than 450 EST markers. Two mapping populations, TTC1 and TTC2, derived from crosses of two creeping x basin wildrye hybrids crossed with one creeping wildrye tester plant have been used for genome analysis of biomass heterosis and many other important perennial grass traits including plant height and rhizome spreading; leaf and culm size; flowering and reproductive traits; seed shattering and seed dormancy; salinity tolerance; fiber, lignin, mineral, and protein content. The creeping x basin wildrye hybrids, parents, and mapping populations were also evaluated for low-input biomass production over three years at two agricultural research farms representative of productive, high-elevation, semiarid, cold-growing environments in the western U.S. The creeping x basin wildrye hybrids show significant high-parent heterosis and generated significant QTL effets in the TTC1 and TTC2 mapping populations. However, the biomass QTLs were population specific and could not be explained by a simple combination of plant height and rhizome QTLs as was initially hypothesized.