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, other diseases, and acceptable agronomic and end-use characteristics.

2) Investigate and implement marker-assisted selection for Fusarium head blight resistance as a compliment to field-based selection.

Progress on Objective 1, HRS Germplasm, Varieties -- (note: several other funding sources contribute to this objective, including the Minnesota Wheat Research and Promotion Council and the U.S. Wheat and Barley Scab Initiative)

•  One hard red spring wheat line, MN95002 was released as ‘Oklee’ in January 2003.  This line has high grain yield, test weight, and grain protein and is moderately resistant to FHB, similar to the variety 2375. One other advanced experimental line, MN97803, was increased by the Minnesota Crop Improvement Association on 12 acres in 2003.  This line is similar to HJ98, but has higher grain protein and test weight.

•  Field nurseries to evaluate reaction to septoria and tan spot, important leaf spotting pathogens, were established to screen varieties and advanced breeding materials in 2003.  The septoria nursery was in collaboration with Char Hollings-worth in Crookston and the tan spot nursery with Ruth Dill-Macky on the St. Paul campus. These nurseries will be continued in the future to better characterize varietal response to these diseases and aid in selections.

•  Five new experimental lines were grown in the 2003 Uniform Regional Scab Nursery.  These lines were identified in previous testing as having improved levels of FHB resistance.   These lines combine FHB resistance from different sources and are candidates for germplasm release.

•  During the 2003 growing season, 385 and 161 experimental lines were evaluated in preliminary and advanced yield trials, respectively.  FHB-inoculated, misted replicated nurseries were established at Crookston, Morris, and St. Paul.  These nurseries involve collaboration with agronomists at Crookston and Morris, and personnel from the Plant Pathology Department.  Data on FHB severity (spread of disease symptoms within the spike) was collected for all materials.  At least 50 spikes of grain were harvested from all nurseries except Scab1 and Scab2 from St. Paul that were badly lodged.  Threshing of grain for determination of VSK (visually scab-damaged kernels) and DON are in progress.  Entries from the 2003 Scab1 nursery are being tested in the greenhouse for reaction to point inoculation with FHB.

Progress Objective 2, Marker-assisted Selection -- In 2003, 38 parents of F4’s (advanced crosses) were screened for the presence of multiple QTLs (quantitative trait locus, or genetic location where a resistance trait is expressed) for FHB resistance. This information aided our selection among the F4 families. Several hundred F5 selections will be screened individually for presence of these expressed traits during the winter of 2003/2004.  Emily Wennerlind, assistant scientist, is responsible for this work and also provides overall coordination of lab-based activities as well as training of all personnel, including one to two undergraduate student workers.

Dr. Sixin Liu’s major effort has been to identify DNA markers more closely linked with the QTL for FHB resistance on chromosome 3BS.  He has analyzed genetic linkages between rice and wheat in this chromosome region, leading to genetic markers used to create a high density genetic map.  The Liu and Anderson (2003) Genome paper demonstrates how the genomic resources of rice can be leveraged for genetic mapping in wheat and other grasses.

This research is an important step in the wheat breeding process.  Once a gene has been marked, we can test for its presence in different breeding lines. Molecular markers allow breeders to bypass the need for screening hundreds of plants for the absence or inclusion of a desired or undesired gene, thus bringing greater efficiency (and less expense) to the process of developing improved spring wheat varieties.

Marker-assisted selection is not the same as biotechnology; it is not taking the genes of one organism and inserting them into another. Rather, it is identifying where a particular trait is located within a plant’s genetic makeup. Molecular markers are essentially a tremendously accurate means of “fingerprinting” germplasm, enabling us to follow traits or genetic makeup in the course of wheat breeding – similar to marking a trail to navigate through the woods.

– Dr James A. Anderson, University of Minnesota wheat breeder