P-21
Molecular breeding to improve grain yield in high quality two-row malting
barley. Production of high-quality malting barley is limited by competition from
higher-yielding feed barley cultivars in the Northwest USA. This persistent
problem has not been overcome by conventional barley breeding. The availability
of high-quality malting barley cultivars that are competitive in yield with the
best feed barley cultivars would benefit barley growers and the malting and
brewing industries. The objectives of this study were to use molecular breeding
technology to improve two-row malting barley and to verify specific genetic
effects. Introgression of two putative yield quantitative trait loci (QTLs) on
chromosome 2HL and one on chromosome 3HL from 'Baronesse' into 'Harrington' was
attempted via molecular marker assisted backcrossing (BC). The intended result
is the development of lines with yield equal to or greater than Baronesse and
malting quality equal to or greater than Harrington; that is lines with
Baronesse yield QTLs in a Harrington genetic background. Sixty-four of 112 or 57
percent of the BC lines equaled or bettered the yield of Baronesse in the 2000
field tests. Over three locations in the 2001 tests, 17 of 28 or 61 percent of
the BC lines advanced equaled the yield of Baronesse. Considering all tests the
highest-yielding BC lines averaged 97 to 105 percent of Baronesse. All but one
of the highest-yielding BC lines have at least one of the three yield QTLs from
Baronesse. Twenty-one of 28 or 75 percent of the BC lines advanced to the 2001
field trials had malt quality scores higher than Harrington. The five lines
advanced to 2002 state yield trials had malt extracts ranging from 80.7 to 81.4
percent vs 80.7 and 78.1 percent for Harrington and Baronesse, respectively. The
high proportion of high-yielding and high-quality lines is expected in molecular
breeding, whereas it is not in conventional breeding. Genotypic selection is
expected to be more precise than phenotypic selection. Extent of the Harrington
genetic background in the BC lines partially explains variation among the lines.
The interaction or epistasis among the genes of both quantitative characters,
yield and malting quality, also play a role in the variation observed. Tests
thus far are very encouraging for developing a breakthrough two-row malting
cultivar with high yield and high quality by molecular breeding.
Steve Ullrich is a Professor in the Dept. of Crop and Soil Sciences at
Washington State University. He came to WSU in 1978 after obtaining the Ph.D.
degree from Montana State University. Current research includes molecular
genetics study of barley adaptation and quality traits and cultivar development.
He also teaches and advises undergraduate and graduate students. He has been
active in the North American Barley Genome Mapping Project, formally as a
Steering Committee member and currently as a researcher. He is a Northwest
representative of the National Barley Improvement Committee and the
NBIC/USDA-ARS Barley Crop Germplasm Committee.
S.E. ULLRICH (1), A. Kleinhofs (1), D. Schmierer (1), D.A. Kudrna (1), V.A.
Jitkov (1), and B.L. Jones (2). (1) Washington State University, Pullman, and
(2) USDA-ARS, Madison, WI.