Still Selecting Wheat Varieties?

Here’s Some Last-Minute Points

By Tracy Sayler

Still making last-minute decisions on what spring wheat varieties to plant? Here are some points to consider from University of Minnesota spring wheat breeder Jim Anderson.  This information is based on Minnesota research, so it would be most relevant to the Red River Valley (the graph numbers correspond with the numbers in the text below).

1. Leaf Rust Ratings
Don’t underestimate the yield impact that leaf rust can have – Anderson notes that a number of fields planted to Trooper in 2004 had a 20-25% yield reduction to stripe rust alone.  Also keep in mind that leaf rust ratings can change in just a few years as variety susceptibility to rust changes.  For example, the leaf rust ratings for Oxen and Parshall were downgraded this year.  The varieties marked with an asterisk means that (will need to clarify what exactly the asterisk means with Jim to finish this sentence). Anderson notes that any variety that’s not rated R or MR could be vulnerable to at least some rust damage, if rust spores blow in from the south and conditions are right for infection.

Variety	Disease Severity
Briggs	R
Banton*	R
Steele-ND*	R
Knudson	R
Trooper*	MR (MS-S stripe rust)
Granger*	MR
Mercury	MR
Alsen	MR
Norpro	MR
Oklee	MR-MS
Freyr*	MR-MS
Granite	MR-MS
Saturn*	MR-MS
Walworth	MS (MS stripe rust)
Reeder	MS
Hanna	MS
Polaris*	MS
Oxen	MS-S
Parshall	MS-S
Ingot	S

2. Scab Ratings
Unlike rust, varietal ratings for scab change very little, if at all.  “The scab fungus doesn’t change much from one year to another,” Anderson says. He likes what he sees from the new variety Freyr thus far but notes that while Alsen and Hanna have better scab tolerance than many other varieties, they will also yield less. 

While Ingot and Parshall are rated better than others for scab tolerance, “they are so susceptible to leaf rust that I wouldn’t recommend either of them,” says Anderson.  The scab tolerance level of Steele-ND isn’t rated as high by the U of M (MS) compared to NDSU, which rates Steele-ND as MR/MS, based on limited testing. “In the field, we have found it to be moderately susceptible.  The data is based on six environments in Minnesota, so I am pretty confident in that rating.”

Anderson says of Oxen: “Be ready with a fungicide, it is fairly susceptible if conditions are right for scab.”  Mercury, though it possesses a higher yield potential than many other varieties, is also highly vulnerable to scab. Anderson compares its scab susceptibility to Norm, often used as a scab-susceptible check in research plots.

The grain soundness score represents the variety’s ability to maintain plump, sound kernels under scab pressure, with 1 = good, 5 = poor.

Variety	Disease Severity	Grain Soundness
Alsen	MR	2.0
Freyr	MR	2.0
Hanna	MR	2.0
Ingot	MR-MS	2.0
Parshall	MR-MS	2.0
Banton	MR-MS	2.5
Briggs	MR-MS	2.5
Granger	MR-MS	2.5
Granite	MR-MS	2.5
Knudson	MR-MS	2.5
Oklee	MR-MS	2.5
Tropper	MR-MS	2.5
Walworth	MR-MS	2.5
Steele-ND	MS	2.5
Oxen	MS-S	3.0
Norpro	MS	3.5
Polaris	MS	3.5
Reeder	MS	3.5
Saturn	MS	3.5
Mercury	S	5.0

3. Straw Strength
Groupings of 20 hard red spring wheat varieties categorized by straw strength.  The different bar sizes in the graph (i.e. Parshall the tallest, Trooper the smallest) is an indication of plant height.  Consider at least one variety with strong or very strong straw strength if you’re concerned about standability.  Of course, consider yield, quality, and other agronomics as well, but standability is a key consideration in comparing between two varieties with all other information being the same.

4. Pre-Harvest Sprouting Rating
Anderson and the U of M have been evaluating HRSW varieties for their ability to resistant pre-harvest sprouting, which can be a problem in lingering wet conditions at harvest (like 2002 and 2004).  Pre-harvest sprouting is genetically correlated with kernel color: generally, white-seeded varieties are more susceptible; darker red more resistant. Pre-harvest germination is triggered when the mature kernels in the standing wheat head absorb water and generate enzymes (including alpha-amylase) that break down starch and protein in the endosperm that are used in the kernel’s growth. The germination process begins within the kernel before small shoots become visible. “That’s why you can have low falling numbers from wheat even if it’s not visibly sprouted.”

Alpha-amylase enzyme activity negatively affects breadmaking properties of flour made from sprout-damaged wheat.  The Falling Number instrument is used to measure this, recording the time in seconds required for a plunger to fall through a slurry of ground wheat and water. The more enzyme activity in this mix, the faster it takes the plunger to drop the measured distance.  A low falling numbers reading of 60 seconds would represent a highly damaged sample; 400 seconds would represent a very favorable, sound sample with a high falling numbers count.  A number of 250 is generally recognized as a minimum standard, though specifications can vary from that.

5. New Varieties, 2004 Releases

Anderson gives additional notes about these new varieties:

Banton – “There doesn’t appear to be any reason not to grow this variety.  There are no real significant weaknesses, it will be competitive.”

Freyr – “Worth a try. It looks like it will deliver”

Granger – “Very large seed, up to 50% larger than some varieties, so watch seed count/planter calibration with this variety at planting.”

Polaris, Saturn – “The genetic background of these two varieties comes from Germany.  Be aware that they are extremely late – I was getting worried about whether these two would come through last year.”

Steele-ND – “One of the higher test weights available.”

Trooper – “Powdery mildew might be something to watch with this variety. Generally powdery mildew is not much of a problem unless we have a cool season, and it is more likely to show up the further north you are.”

Name	Pluses	Minuses
Banton (Trigen)	Straw strength, leaf rust, test weight
Freyr (AgriPro)	Scab	Straw strength
Granger (SDSU)		Straw strength
Polaris (North Star Genetics)	Straw strength	Protein, leaf rust, scab
Saturn (North Star Genetics)	Protein, straw strength	Test weight, scab
Steele-ND (NDSU)	Scab, test weight, protein, leaf rust	Straw strength
Trooper (Westbred)	Straw strength	Protein, stripe rust, powdery mildew

6-7. Northern and Southern Valley Varieties

These are short lists of varieties that seem particularly well-suited for northern and southern ends of the Red River Valley, but by all means are not exclusive. The bottom line, says Anderson, is the variety that fits well on your farm.

Northern Valley (N. of Hwy 2)

Name	Pluses	Minuses
Knudson (2001 AgriPro)	Yield, leaf rust	Protein
Alsen (2000 NDSU)	Scab, protein, test weight	Yield
Briggs (2002 SDSU)	Leaf rust, yield	Straw strength
Oklee (2003 U of M)	Protein, test weight	Straw strength

Southern Valley (S. of Hwy 2)

Name	Pluses	Minuses
Knudson (2001 AgriPro)	Yield, leaf rust	Protein
Freyr (2004 AgriPro)	Scab	Straw strength, yield
Steele-ND (2004 NDSU)	Scab, protein, test weight	Straw strength
Briggs (2003 SDSU)	Leaf rust	Straw strength

8. Performance is Slipping
These are varieties that, while they may still have their merits or have performed well in the past, may be vulnerable to certain problems, weaknesses, or performance issues, based on last year’s observations in Minnesota.

Name	Minuses
Granite (2002 Westbred)	Falling numbers
Oxen (1995 SDSU)	Leaf rust
Parshall (1999 NDSU)	Leaf rust
Reeder (1999 NDSU)	Leaf rust
Walworth (2001 SDSU)	Stripe rust

Varietal Information Online

2005 Minnesota Varietal Trials publication with information on 18 crops: www.maes.umn.edu .

NDSU crop production guides for 2005, including variety trial performance data: www.ag.ndsu.nodak.edu/cropprod.htm .

South Dakota State University variety trial information:
 http://plantsci.sdstate.edu/varietytrials/vartrial.html .