New U of M Variety “Oklee” Moderately Resistant to FHB

The objectives of accelerated breeding of FHB-tolerant wheat at the U of M are to:

1) Develop high yielding, hard red spring wheat germplasm and varieties with improved resistance to FHB and acceptable agronomic and end-use characteristics.

2) Identify DNA markers for use in marker-assisted selection for FHB resistance in wheat.

One hard red spring wheat line, MN95002 was approved for release at the fall 2002 meeting of the Crop Variety Review Committee.  This line, called “Oklee,” has high grain yield, test weight, and grain protein and is moderately resistant to FHB, similar to the variety 2375.  It is one of the earliest maturing varieties ever released by the U of M. Oklee seed will be grown mostly by seed producers this year, with seed more widely available in 2004.

Another line, MN97803, was approved for preliminary increase in 2001 and continued increase by the Minnesota Crop Improvement Association in 2002.  This line is similar to HJ98, but has higher grain protein, test weight, and better FHB resistance, similar to 2375.

Five new experimental lines were grown in each of the 2001 and 2002 Uniform Regional Scab Nurseries. These lines were identified in previous testing as having improved levels of FHB resistance. Several of these lines combine FHB resistance from different sources and will be released as germplasm.

A total of 5,686 plots containing breeding material and FHB resistance sources (excludes mapping populations) were screened in inoculated, misted field FHB nurseries in Crookston, Morris, and St. Paul during the 2001 growing season.  These evaluations included 189 lines in advanced yield trials and 382 lines in preliminary yield trials.  A total of 2,972 plots containing breeding material (excludes mapping populations) were screened in inoculated, misted field FHB nurseries at Crookston and St. Paul during the 2002 growing season. These evaluations included 136 lines in advanced yield trials and 393 lines in preliminary yield trials.

Approximately 3,200 early generation breeding lines were screened during fall 2001, spring 2002, and fall 2002 greenhouse studies to assess reaction to FHB inoculation.  These results are used to choose lines for advancement to preliminary yield trials and introgression of new FHB resistance genes.

Based on FHB field screening data of 14 spring wheat cultivars evaluated in 10 Minnesota nurseries, protocols for developing more efficient early generation and advanced-generation materials have been derived.  The data showed that for initial evaluations, susceptible material could be reliably identified and discarded based on data from 2 replicates in three environments, and advanced generation material requires 5 to 7 environments of replicated testing to accurately assess FHB reaction.

Marker-assisted selection was used to screen approximately 500 F4 lines during the summer of 2001, with screening of F4 materials from 2002 nurseries in progress. Seventy-four FHB resistant and susceptible lines from throughout the world have been genotyped with four markers.  Resistant lines have been identified that may carry novel FHB resistance genes.  They warrant further study and should be used as parents in breeding for higher FHB resistance levels.

— James Anderson, U of M wheat breeder

Wheat Geneticist Helps Identify Promising Genes
As a wheat geneticist with the USDA’s Agricultural Research Service in St. Paul, David Garvin works in cooperation with U of M crop scientists, focusing in large part on genetic and molecular aspects of FHB resistance in wheat.  He evaluates the type, number and location of genes that code for desirable and undesirable genes that exist within different wheat lines. This information can then assist wheat breeders, including the U of M’s Jim Anderson, to develop new wheat varieties that possess desirable characteristics, without undesirable ones.

Garvin also coordinates the uniform regional scab nursery for spring wheat, begun in 1995 by USDA-ARS wheat geneticist Bob Busch, who is now retired.   The nursery, supported in part by the U.S. Wheat and Barley Scab Initiative, includes six different evaluation sites in Minnesota, North Dakota, South Dakota, and Canada.  About 40 wheat lines are evaluated each year, including hard red spring wheat, durum, and plant introductions from both public and private breeding programs. 

The benefits of the uniform regional nursery are two-fold, says Garvin: The coordinated sites provide a vehicle for obtaining multi-site scab resistance data, which is important given the large effect of environment on scab development and severity.  Secondly, the program provides a means of germplasm exchange among wheat breeding programs in the region. An additional benefit is that the coordinated effort provides a record of progress in enhancing scab resistance in wheat germplasm over time.

New Plant Pathologist at NWROC --Crookston
Inoculated, misted screening nurseries for spring wheat and barley were grown for the eighth consecutive year at Crookston during the summer of 2002.  A variety of inoculation and misting methods have been tested, and the objective throughout has been to provide an environment most suited to development of FHB to facilitate screening of breeding material for spring wheat and barley breeding programs. 

Charla Hollingsworth joined the staff at the Northwest Research and Outreach Center last year as a University of Minnesota extension plant pathologist. A graduate of the University of Wyoming, she welcomes grower questions and queries regarding diseases in small grains and other northern-grown crops.  She may be contacted at (218) 281-8627, (218) 280-8174 (cell) email holli030@umn.edu .

Nearly real time weather information continues to be offered on the Northwest Research and Outreach Center web page at http://nwroc.umn.edu/weather/weather.htm .   Historical weather information is also collected on the same web page, and development of a database is continuing to allow recovery of weather records spanning any desired timeframe.

– John Wiersma, associate professor of agronomy; Galen Thompson, agronomy research fellow, Northwest Research and Outreach Center, Crookston