OKLAHOMA
Germplasm Enhancement for RWA Resistance
D.W. Mornhinweg, and D.R. Porter
USDA-ARS Plant Science and Water Conservation Research Laboratory
Stillwater, Oklahoma
Prebreeding for adapted germplasm lines
The prebreeding program is designed to bring resistance genes from unadapted germplasm lines into adapted malting and feed barley backgrounds for all barley growing regions in the U.S. It involves repeated backcrossing of both spring and winter barleys with intermittent RWA screening and a time commitment of approximately seven years from the first cross until homozygous resistant BC3F3 lines can first be evaluated as observation lines in the field. Spring lines can be developed at an accelerated pace because of the potential for 2 generations per season. This is an ongoing process involving many resistant lines and adapted cultivars currently in all phases of the program. By 2002, the majority of crosses had been made and the emphasis had shifted to field testing of advanced lines and increase of pure homozygous resistant seed for germplasm release.
Field testing in 2002 was preformed in cooperation with Phil Bregitzer (spring barley) and Darrell Wesenberg/Charles Erickson (winter barley) all scientists with the USDA-ARS in Aberdeen, Idaho; Bob Hammon and Frank Piears, Colorado State University; Steve Ullrich, Washington State University, and David Baltensberger, University of Nebraska. Preliminary Yield Trials were conducted at one location in Idaho on a total of 37 adapted RWA-resistant winter barley germplasm lines involving 2 susceptible winter barley backgrounds and 10 RWA-resistant sources. Another winter preliminary yield trial was conducted on 75 advanced generation winter barley germplasm lines in Fruita, CO involving 2 susceptible backgrounds and 8 RWA-resistant sources. Preliminary yield trials were conducted at 4 locations in Idaho for 80 advanced generation adapted spring barley germplasm lines involving 14 susceptible backgrounds and 23 RWA-resistant sources. A dryland preliminary yield trial was conducted at 2 locations in CO and 1 location in NE on 20 advanced generation spring barley germplasm lines in an Otis background with resistance from 2 sources. A 27 entry subset of these lines was also evaluated in a Preliminary yield trial in Aberdeen, Idaho.
Six hundred and twenty advanced generation adapted winter RWA-resistant barley germplasm lines were evaluated in headrows at Aberdeen, Idaho and rows selected for future yield testing in 2003. Heads were selected from segregating rows for RWA screening and further field testing in 2003. These lines involved 3 susceptible backgrounds and 11 RWA-resistant sources. 300 adapted BC3F3/4 winter barley germplasm lines were evaluated in observation rows in Western Colorado involving 1 susceptible background and 5 RWA-resistant backgrounds. Rows were selected for preliminary yield testing in 2003 and heads were selected from segregating rows for further RWA screening and field testing in 2003. Three hundred and sixty-five advanced generation spring barley germplasm lines were evaluated by Steve Ullrich in Washington State involving 3 susceptible backgrounds and 6 RWA-resistant sources. Four hundred advanced generation spring barley germplasm lines were evaluated in observation rows in Aberdeen, Idaho involving 4 susceptible backgrounds and 2 RWA-resistant sources. Homozygous resistant rows were selected for preliminary yield testing in 2003 and heads were selected from segregating rows for evaluation in headrows in 2003 in Idaho. Numerous adapted RWA-resistant spring barley germplasm lines were increased for pure seed in the field in Idaho and in the greenhouse in Stillwater, OK.
Approximately 1,400 additional winter barley lines were increased in the greenhouse for possible inclusion as observation rows in 2003. These lines involved 2 susceptible parents and 11 RWA resistance sources. Another 489 winter barleys were also increased for possible inclusion as observation rows in 2003 involving 3 susceptible parents and 7 sources of RWA resistance. A total of 4,688 advanced generation spring barleys were increased for pure seed for potential release of 90 adapted germplasm lines. Six BC3F1 crosses were made involving 6 susceptible cultivars and 1 RWA-resistant source. A total of 2,730 winter barley lines and 3,492 spring barley lines were screened in support of the prebreeding effort.
Genetic Studies
Complete genetic analysis has been performed on nine out of a total of 108 RWA -resistant lines developed by the USDA-ARS in Stillwater. All nine lines showed multiple gene control for RWA resistance. Seed has been developed and future genetic studies planned for the remaining 99 lines. Genetic diversity studies are also planned for all resistant lines to determine if these lines carry different genes for resistance to RWA. This type of analysis requires 3 years for development of seed necessary for each test. TC1F1 were made for future genetic diversity studies. 6 TC1F1 winter barley populations were selfed and increased for future genetic diversity studies.
Cooperative screening
Sixty-four advanced lines were screened for resistance for 1 barley breeder.
Bird Cherry oat aphid
Morphological measurements were made to determine the effect of BCO aphid feeding on 10 barley accessions with 4 replications and 3 treatments. Additional measurements were made on 69 lines with 2 reps and 2 treatments towards an understanding of aphid/host interaction and the potential of a visual or measurable trait for future screening of barleys for BCOA resistance. Development of a greenhouse seedling screening test would make screening of large barley collections fast and effective for identification of BCOA-resistant barleys.
Six hundred and 30 BC3F3 lines in a Post 90 background, already determined to be homozygous resistant for RWA, were screened for resistance to GB biotype I. Lines with resistance to both aphids would be advantageous in several barley growing areas. Six F1 and 8 backcrosses were made for inheritance and genetic diversity studies of greenbug resistance.
Germplasm Enhancement
Dolores W. Mornhinweg, Geneticist
David R. Porter, Research Geneticist
Cooperators
Darrell Wesenberg, Research Agronomist, USDA-ARS, Aberdeen, ID
Phil Bregitzer, Research Geneticist, USDA-ARS, Aberdeen, ID
Berne Jones, Research Biochemist, USDA-ARS, Madison, WI
Frank Piears, Professor, Colorado State University
Bob Hammond, Professor, Colorado State University
Dave Blatsenberger, Professor, University of Nebraska
Steve Ullrich, Professor, Washington State University
Mornhinweg, D.W., D.R. Porter and J.A. Webster. 2002. Inheritance of Russian Wheat Aphid Resistance in Spring Barley Germplasm Line Stars-9577B. Crop Sci. (In Press).