Details for: PI 701909, Leymus hybr., 'L-74X'


Summary Data
Taxonomy:
Leymus hybr.
Cultivar:
'L-74X'
Origin:
Developed – Utah, United States
Received by NPGS:
01 Feb 2023
Form Received:
Seed
Life Form:
Perennial
Availability
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Core Passport Data
Taxonomy:
Leymus hybr.
Cultivar:
'L-74X'
Origin:
Developed – Utah, United States
Received by NPGS:
01 Feb 2023
Form Received:
Seed
Life Form:
Perennial
Source History
Developed

Utah, United States

Developer(s):
Accession Names and Identifiers
'L-74X'
Type: Cultivar name

Narrative
Basin wildrye is somewhat indeterminate and shatters its seed. To avoid shattering losses, growers tend to harvest basin wildrye seed prior to maximal physiological maturity. To resolve the intersecting problems of floral indeterminacy and seed shattering, USDA-ARS released the L-74X basin wildrye X creeping wildrye germplasm on August 26, 2021. While L-74X has a narrow genetic base due to a biparental cross in its history, it can be used to introgress the non-shattering recessive sh6 allele of creeping wildrye (2n = 4x = 28) into 4x basin wildrye and closely related 4x Leymus species. L-74X originated with hybridization between 4x populations of basin wildrye and creeping wildrye, while eight generations of recombination and natural selection restored fertility to the interspecific hybrid. Intentional selection led to fixation of the sh6 allele. Averaged across two years, shattering genotypes (Sh6/sh6) averaged 19.4% greater (P < 0.05) seed yield per spike 23 days after pollination (DAP), but by 95 DAP non-shattering genotypes (sh6/sh6) averaged 167% greater (P < 0.05) seed yield per spike. Germination increased from 72.1% at 23 DAP to 86.4% at 95 DAP. The sh6 allele allows seed growers to delay seed harvest, concomitantly reducing shattering losses and improving physiological seed quality
Leymus hybr.
Genus:
Leymus
Family:
Poaceae (alt. Gramineae)
Subfamily:
Pooideae
Tribe:
Triticeae
Nomen number:

310513
Comment:
interim designation used in GRIN for Leymus hybrids which lack an acceptable binomial
Verified:
09/23/1986 by ARS Systematic Botanists.
Other conspecific taxa
Autonyms (not in current use), synonyms and invalid designations
Common names
Annotations
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Pedigree
Description:
L-74X traces to an initial 1998/1990 interspecific F1 cross (Leymus cinereus female x L. triticoides male) between multiple plants of M10 (USDA Acc:636), an L. cinereus population received from Sylvester Smoliak (Agriculture Canada, Lethbridge, AB), and A30 (PI 537359; USDA Acc:641), an L. triticoides population collected by Kay Asay (USDA-ARS, Logan, UT) near Jamieson, OR. In 1992, the F2 progeny of the cross were generated. Eight generations of recombination occurred following the initial hybridization, which facilitated the restoration of fertility in the interspecific hybrid population. Partway through this process, a controlled biparental cross of two individual L-57S plants, L-57S-491 (sh6/sh6) x L-57S-577 (SH6/sh6) was made to test and validate linkage of the Ltc096.158 marker and the sh6 seed retention gene. This created a genetic bottleneck, severely reducing genetic variation. and necessitating a germplasm rather than a cultivar release. In the final generation, 70 non-shattering (sh6/sh6) selections were intermated and harvested for seed, constituting L-74X.
Intellectual Property Rights
Journal of Plant Registration. GP-106, OTHER GRASSES. Issued: 01 May 2023.
  • Larson, S. R., T. A. Jones, & K. B. Jensen. 2023. Registration Of L-74x Non-Shattering Basin Wildrye X Creeping Wildrye. J. Pl. Registr. 17(2):397. DOI: 10.1002/plr2.20293.