Annual Progress Report on Malting Barley Research March, 2002

106
GERMPLASM ENHANCEMENT FOR RWA RESISTANCE
D.W. Mornhinweg, D.R. Porter, J.A. Webster
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 with intermittent screening with 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. This is an
ongoing process involving various resistant lines and adapted cultivars currently in all
phases of the program. Field testing was preformed in cooperation with Phil Bregitzer
(spring barley) and Darrell Wesenberg/Charles Ericksen (winter barley) all scientists with
the USDA-ARS in Aberdeen, Idaho; Bob Hammon and Frank Piears, Colorado State
University; and David Baltensberger, University of Nebraska. In the summer of 2001,
ten advanced generation RWA-resistant spring barley lines were evaluated in replicated
yield trials at 4 locations in Idaho, 2 locations in Nebraska and 2 locations in Colorado.
Five of these lines involved six, 6-row backrounds and five lines involved five, 2-row
backgrounds with RWA resistance in all ten lines derived from STARS-9301B.
Preliminary Yield Trials were conducted at one location in Idaho on a total of 33 adapted
RWA-resistant winter barley germplasm lines involving three susceptible winter barley
backgrounds and 9 RWA-resistant sources. Preliminary yield trials were conducted at 4
locations in Idaho for 187 advanced generation adapted spring barley germplasm lines
involving 14 susceptible backgrounds and 23 RWA-resistant sources. A preliminary
yield trial was conducted in Stoneham, Colorado on 114 adapted advanced generation
RWA-resistant spring barley germplasm lines in an Otis background involving 3 different
sources of RWA resistance. A 30 entry subset of these lines was also evaluated in a
Preliminary yield trial in Aberdeen, Idaho. Five hundred and sixty advanced generation
adapted winter RWA-resistant barley germplasm lines were evaluated in headrows at
Aberdeen, Idaho and rows selected for future yield testing in 2002. These lines
involved one susceptible background and 9 RWA-resistant sources. 1,000 adapted
BC3F3/4 winter barley germplasm lines were evaluated in observation rows in Western
Colorado involving 3 susceptible backgrounds and 7 RWA-resistant backgrounds and
600 adapted BC3F3/4 winter barley germplasm lines were evaluated in observation rows
in Aberdeen, Idaho involving 2 susceptible background and 7 RWA-resistant
backgrounds. Rows were selected for preliminary yield testing in 2002 and heads were
selected for evaluation in headrows in 2002 in both Idaho and Colorado. 1,000 BC3F3/4
adapted spring RWA -resistant barley lines were evaluated in observation rows in Idaho.
Selections were made for preliminary yield trials in 2002. Numerous adapted RWAresistant
spring barley germplasm lines were increased for pure seed in the field in Idaho
and in the greenhouse in Stillwater, OK. Eight spring BC3F2 populations involving 6
susceptible backgrounds and 2 RWA-resistant sources and 11 winter BC3F1 populations