Technical Session 05: Malts and Grain Session
Richard D Horsley, North Dakota State University, Department of Plant Sciences, Fargo, ND USA
Co-author(s): Magan Lewis, North Dakota State University, Department
of Plant Sciences, Fargo, ND, USA; Fabio Pedraza-Garcia, Seeds 2000,
Breckenridge, CO, USA; Ana Correa-Morales, North Dakota State
University, Department of Plant Sciences, Fargo, ND, USA; Shiaoman Chao,
USDA-ARS, Cereal Crops Research Unit, Fargo, ND, USA; Ronshuang Lin,
University of Maryland, College Park, MD, USA; Paul Schwarz, North
Dakota State University, Department of Plant Sciences, Fargo, ND, USA
ABSTRACT: Brewers in the United States who use six-rowed barley (Hordeum vulgare
L.) have historically used cultivars with similar malt quality
profiles. Around the year 2000 this changed, with some brewers
preferring cultivars that produce higher levels of alpha-amylase and
have increased protein modification during malting, while other brewers
prefer cultivars that have moderate levels of these two characters. Two
cultivars that meet these differing criteria are Stander, which produces
increased levels of alpha-amylase, soluble protein, and free amino
nitrogen (FAN); and Robust, which produces moderate levels of these malt
quality parameters. In addition, Robust and Stander differ in their
resistance to preharvest sprouting (PHS), with Stander being very
susceptible and Robust being moderately resistant to PHS. An interesting
characteristic of Stander and Robust is that they are very closely
related. This feature should make it possible for us to determine the
genetic basis for the dissimilarities in the two cultivars and to use
this information to design a marker assisted breeding strategy for
developing cultivars that meet specific brewers’ needs. The markers
associated with specific quality parameters in Robust or Stander can be
thought of as their “fingerprint.” Geneticists call this fingerprint a
haplotype. A doubled-haploid mapping population from the cross Robust ×
Stander was developed. A genetic map for this cross comprised of single
nucleotide polymorphism (SNP), simple sequence repeat (SSR), and
diversity array technology (DArT) markers was constructed. The
polymorphic markers were grouped into 19 linkage groups, which were
associated with six of the seven barley chromosomes. Chromosomes 2H, 4H,
and 6H had relatively large portions of the chromosomes mapped, while
chromosomes 1H, 3H, and 5H had many small segments mapped. Because of
the specific quality parameters required for malting barley, it is not
surprising that only portions of the chromosomes were mapped. Many of
the segments not mapped would be regions where genes controlling malt
quality are fixed in a favorable state. Additionally, the regions where a
map was constructed are likely to include the specific genes that
determine the quality differences observed in Robust and Stander. The
map constructed was used to identify quantitative trait loci (QTL)
controlling seedling dormancy, alpha-amylase activity, soluble protein
concentration, Kolbach index, FAN, wort beta-glucan, and concentrations
of wort carbohydrates. QTL controlling correlated traits often mapped to
similar sites. For example, QTL controlling alpha-amylase, Kolbach
index, FAN, and wort color mapped to a similar region in chromosome 6H. A
preliminary “fingerprint” or haplotype of markers that differentiate
Robust-type from Stander-type barley cultivars will be discussed.
Richard
Horsley is the barley breeder at North Dakota State University and head
of the Department of Plant Sciences. Richard earned his Ph.D. and M.S.
degrees in agronomy from North Dakota State University and his B.S.
degree in agronomy from the University of Minnesota. The primary goal of
his breeding project is to release and develop six-rowed and two-rowed
malting barley varieties acceptable to barley producers in North Dakota,
adjacent states, and the malting and brewing industry. Current research
efforts include the determination of DNA “fingerprints” that
differentiate varieties for specific brewer’s needs and identification
of genes for resistance to preharvest sprouting.
VIEW PRESENTATION 19
