Native Grasses for Biomass Production at High Elevations - Industrial Crops: Breeding for BioEnergy and Bioproducts - page 106

Major Breeding Achievements

The octoploid (2 n 56) basin wildrye cultivar “Magnar,” released in 1979 [ 11 ], is

believed to have originated from southeastern British Columbia. The tetraploid
(2 n

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28) basin wildrye cultivar “Trailhead,” originally collected near Roundup,
Montana, was released in 1991 [ 12 ]. Cultivars Magnar and Trailhead represent the
two most widespread and important genetic races, the Columbia race and Rocky
Mountain race, respectively [ 44 ]. Magnar and Trailhead can be visually distin-
guished by the presence or absence of glaucous cuticle wax, which appears to be
controlled by a single dominant gene orthologous to the wheat Inhibitor wax ( Iw )
gene [ 46 ]. Both Magnar and Trailhead have been widely used in seed mixtures with
other grass species on public and privately owned rangelands of the western USA.
“Continental” is a cultivar [ 50 ]) derived from a chromosome-doubled Trailhead
pollinated by the natural octoploid, Magnar, which shows increased seed mass and
seedling vigor compared to the parental cultivars [ 50 ]. The cultivar Continental
segregates for the glaucous trait [ 50 ] and presumably segregates for other genes that
distinguish its Columbia and Rocky Mountain parental races. The basin wildrye
cultivar “Washoe” was collected from a natural population growing on phytotoxic
soils near the now defunct Washoe smelter stack in western Montana, which is
contaminated with arsenic, cadmium, copper, lead, and zinc [ 13 ].
The only creeping wildrye cultivar Rio, released in 1991, was originally col-
lected in Kings Valley, California, and is used for soil stabilization in riparian areas,
forage production, and reclamation of saline, irrigated croplands and pasturelands
[ 14 , 32 ]. Another cultivar, “Shoshone,” was originally released as creeping wildrye,
but morphological characters [ 21 ] and chloroplast DNA sequences [ 51 ] of Sho-
shone are similar to Eurasian Leymus multicaulis [ 14 ].

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Breeding Strategies, Traits, and Goals

Growing up to 3 m tall [ 7 , 10 ], basin wildrye has relatively high biomass accumu-
lation potential, with up to 13,300 kg ha 1 observed with no irrigation or fertilizer
in Cache Co., UT. Basin wildrye has a deep and extensive root system [ 52 , 53 ]; high
photosynthetic capacity, nitrogen-use efficiency, and intrinsic water-use efficiency
[ 54 ]; and salt tolerance [ 24 - 26 ] that enable basin wildrye to maintain growth and
physiological activity during dry summer periods when many other perennial
grasses are dormant [ 54 ]. Basin wildrye tends to begin spring growth early, flower
later, and stay green longer than other cool-season native perennial grasses, which
extends the vegetative growth of this species [ 54 , 55 ]. Biomass production can be
enhanced from low levels of fertilization and irrigation, but once established it is a
low-maintenance plant requiring little additional treatment or care [ 23 ]. These traits
of basin wildrye can be useful for low-input biomass production in high-elevation
environments of the Mountain West that are often favored by winter-precipitation