Fargo, North Dakota, USA
August 27, 2020
Tests NDSU researchers conducted this summer for iron-deficiency chlorosis show significant differences among soybean varieties. (NDSU photo)
This summer, researchers in NDSU’s soybean breeding program tested several soybean varieties for iron-deficiency chlorosis.
New North Dakota State University research can help producers select soybean varieties that are more tolerant to iron-deficiency chlorosis (IDC).
During the summer of 2020, the researchers in NDSU’s soybean breeding program tested 206 Enlist, LLGT27, Roundup Ready and Xtend soybean varieties, as well as 33 conventional and Liberty Link varieties, for IDC tolerance.
The test results are based on replicated trials conducted at two locations with a past history of IDC. Visual ratings were made on a 1 to 5 scale, with 1 representing no chlorosis and 5 being the most severe chlorosis. Ratings were taken twice at two different soybean growth stages.
The test results are available at https://www.ag.ndsu.edu/varietytrials/soybean.
“Soybean varieties differ in their tolerance to IDC,” says Hans Kandel, NDSU Extension agronomist. “Selecting a soybean variety with tolerance to IDC is the most important management decision producers can make in avoiding or reducing the negative yield effect of chlorosis.”
IDC was prevalent in many soybean fields in eastern North Dakota and northwestern Minnesota during the 2020 growing season, according to Kandel.
This summer’s tests showed significant differences among soybean varieties. For example, the average scores for the GMO group tested ranged from 1.6 (most tolerant) to 3.1 (the least tolerant variety).
“Producers can utilize the NDSU data to select an appropriate IDC-tolerant soybean variety for a field with known IDC issues,” Kandel says.
No soybean variety is immune to chlorosis, but differences in yellowing and subsequent plant stunting occur between the most tolerant and most susceptible varieties.
Plant leaves with IDC symptoms are yellow with green veins. Yellowing, browning and stunting of the plants during the early vegetative stages will result in less photosynthesis in these plants, compared with healthy green plants, resulting in reduced soybean yields.
Besides evaluating IDC tolerance in soybean varieties, growers are encouraged to look at the genetic yield potential of soybean varieties. Varieties with similar IDC tolerance can vary greatly in their yield potential. NDSU conducts soybean variety yield evaluations throughout the state and results are reported on the NDSU variety trial website (https://www.ag.ndsu.edu/varietytrials/soybean).
The North Dakota Soybean Council provided funding for the studies.
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