Annual Progress Report on Malting Barley Research March, 2007

Minnesota barley disease survey and collection of pathogen isolates.
Disease surveys are useful for identifying economically important pathogens of barley
and determining their impact on yield and quality. A survey was made in the
northwestern part of Minnesota (the primary barley production area in the state) to
ascertain the prevalence and importance of barley diseases in 2006. Nine fields were
visited during the survey conducted on July 12-14. FHB was the most common disease
and detected in 67% of surveyed fields, with observed severities ranging from 0% to
0.2% (Table 1). Net blotch was the next most common disease and was observed in
56% of fields. Net blotch severity ranged from trace to 30%. Other diseases identified
in the survey included bacterial blight, SSLB and crown rust. FHB continues to be a
major disease problem on six-rowed barley in the region as it has for the past 14 years.
However, the severity of FHB was among the lowest observed for this survey in many
years. This was likely due to the very dry weather in northwestern Minnesota. Net
blotch has and continues to be a common disease in barley. In 2005, bacterial blight
was widespread in Minnesota. In 2006, this disease was found again in a number of
fields. Crown rust can be a common disease in Upper Midwest barley fields—its
severity in any one year can vary dramatically.
Determine the virulence phenotype of pathogen isolates and maintain a
pathogen isolate collection. Pathogen isolates are an essential resource for
resistance breeding efforts and the identification of novel sources of disease resistance.
We have over 1000 isolates of various barley pathogens stored at the University of
Minnesota. Over the past year, we tested the viability of all isolates and are in the
process of compiling a database (place of collection, cultivar of origin, virulence pattern,
etc.) on them. We collected more pathogen isolates from the 2006 barley disease
survey. These isolates will be purified and stored for future virulence evaluations. We
conduct the leaf rust virulence surveys for the United States. In 2006, seven isolates of
P. hordei (leaf rust) were received from around the country. Our lab continues to serve
the barley community by testing germplasm for resistance to various diseases and
supplying cooperators with pathogen cultures and germplasm for their studies. As
coordinator for disease and pest resistance genes for the International Barley Genetics
Committee, I also supply information to cooperators on the genetics and mapping of
resistance genes.
Other barley research projects funded from other sources. We conduct a
number of other barley research projects in addition to those funded by AMBA. These
are listed below.
Other Barley Research Projects
Sub-cellular localization and functions of the barley stem rust resistance
receptor-like serine/threonine-specific protein kinase Rpg1. The Rpg1 gene
confers resistance to many pathotypes of the stem rust fungus Puccinia graminis f. sp.
tritici and has protected barley from serious disease losses for over 60 years. Rpg1
encodes a constitutively expressed protein with two tandem kinase domains.
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