REGISTRATION OF 'DOUGLAS' CRESTED WHEATGRASS

REGISTRATION OF 'DOUGLAS' CRESTED WHEATGRASS
Crop Sci. 35: 1510-1511 (1995)

K. H. Asay, K. B. Jensen, D. A. Johnson, N. J. Chatterton, W. T. Hansen, W. H. Horton, and S. A. Young

DOUGLAS is the first hexaploid (2n=6x=42) cultivar of crested wheatgrass [Agropyron cristatum (L.) Gaertner sensu Rato] to be released in North America. It was developed by a research team at the USDA-ARS Forage and Range Research Laboratory, Utah State University, Logan, Utah and was released 1 July 1994 in cooperation with the Utah Agricultural Experiment Station and USDA-NRCS. Douglas was evaluated as 6X-BLR. It was named in honor of Douglas R. Dewey, who established the germplasm base for the USDA-ARS grass breeding program at Logan.

The breeding population was derived from hybrids between an accession from the former Soviet Union (PI 406442) and four other hexaploid accessions, three from Iran (PIs 401076, 401080 and 401085) and one from Turkey (PI 173622). Accession 406442 is characterized by exceptionally broad leaves; it was used as the female parent in all crosses to retain the cytoplasm of this accession in the breeding population.

Two cycles of selection for broad-leaf type, vegetative vigor, seed yield potential, and response to plant pests and drought were completed in spaced-plant nurseries. The C2 population was screened for seed size and emergence from a 7.6-cm seeding depth. Breeder's seed was produced from a composite of 10 selected open-pollinated progenies.

DOUGLAS has larger seed than diploid and tetraploid cultivars, and it exhibited excellent establishment vigor in field-evaluation trials. Based on emergence from 7.6-cm planting depth, seedling vigor of DOUGLAS was significantly greater than the cultivars Nordan, Fairway, and Ephraim and equivalent to the cultivar Hycrest. Although it produces less total forage yield than other crested wheatgrass cultivars, it is leafier and its leaves remain green for a longer period during the growing season than other cultivars. Grazing animals also have preferred Douglas over other crested wheatgrass cultivars under sward conditions. Results from a semiarid range site in western Utah indicated that the in vitro digestibility (IVDMD) of its forage was significantly higher than that of other crested wheatgrass cultivars, particularly later in the growing season.

DOUGLAS is not as resistant to drought as the cultivars Hycrest and Nordan and it is recommended for range sites receiving at least 250 mm of annual precipitation at altitudes below 2,100 m. Under dryland range conditions, a seeding rate of 8 kg ha^-1 is recommended. Douglas produced approximately 400 kg seed ha^-1 in seed-increase blocks on dryland sites receiving 35 cm of annual precipitation. With a single irrigation, seed yields of more than 750 kg ha^-1 have been obtained. This hexaploid cultivar will hybridize with other diploid and tetraploid forms of crested wheatgrass, although the fertility of the hybrid progenies is substantially reduced. Accordingly, isolation from all other crested wheatgrass plants, regardless of ploidy level, is required in seed production fields.

Breeder, Foundation, and Certified seed classes will be recognized. Breeder seed will be maintained by the USDA-ARS Forage and Range Research Laboratory at Logan, UT. Foundation seed will be produced by the USDA-ARS at Logan and distributed to seed growers by the Utah Crop Improvement Association. U.S. Plant variety protection has been applied for under the 1970 act as amended in 1994. Conditions of this license specify that seed of the cultivar DOUGLAS can be marketed only as a class of certified seed. For information regarding supplies of foundation seed, contact: Stanford Young; Utah Crop Improvement Association; Plants, Soils, and Biometeorology Department; Utah State University; Logan, UT 84322-4820.

References

K. H. Asay, K. B. Jensen, D. A. Johnson, N. J. Chatterton, W. T. Hansen, and W. H. Horton, USDA-ARS Forage and Range Research Laboratory, Utah State University, Logan, UT 84322-6300; and S. A. Young, Plants, Soils, and Biometerorology Department, Utah State University, Logan, Utah 84322-4820.