Iron-deficiency chlorosis (IDC) is common in North Dakota and reduces yield. The best way to reduce the yield losses associated with IDC is to select a tolerant cultivar. Growers need data that compares varieties from different private companies in the same environments using the same experimental method. This proposal would permit approximately 350 different GMO company varieties and non-GMO varieties to be evaluated for IDC tolerance. An additional 100 NDSU breeding lines would be evaluated. All private company varieties that have been entered into the Langdon Research and Extension Center (REC), Carrington REC, Minot REC, and Fargo Main Station yield trials will be evaluated for visual ratings of IDC at multiple field locations. In addition, the 100 NDSU lines will be tested genetically for known IDC molecular markers. These data will be contrasted against the field scores to determine accuracy of IDC prediction. The validation of these markers will allow for selection of IDC tolerant varieties in the NDSU program. Visual yellowing that is caused by IDC has been shown to be closely correlated to yield for fields that have IDC. This data will provide an independent confirmation of the IDC tolerance of company products and enable growers to compare varieties from different companies. This proposal will aid growers in selection of tolerant cultivars to increase yield on fields that have a past history of IDC.

The objective is to screen all private company varieties that have been entered into the Langdon Research and Extension Center (REC), Carrington REC, Minot REC, Williston REC and Fargo Main Station yield trials for visual ratings of IDC at multiple field locations with a past history of IDC symptoms. A second objective is to provide visual IDC screening of approximately 100 advanced NDSU breeding lines. The third objective is to evaluate known molecular markers for their accuracy at predicting IDC. These markers can be used to select for IDC tolerant varieties in the NDSU breeding program. Soybean growers need information to aid them in comparing varieties from many different companies for iron-deficiency chlorosis (IDC) in side-by-side comparisons. This data provides unbiased information that enables growers to choose the best variety for their IDC prone fields.

Growers will be provided with data that enables them to identify the best varieties for those fields that are susceptible to IDC. Data will be analyzed and reported in the NDSU bulletin entitled ‘North Dakota Soybean Performance (A -843)’ and posted online at https://www.ag.ndsu.edu/varietytrials/soybean. Validated markers will be used to select only IDC tolerant varieties in future variety development.

Update:
Visual rating for iron-deficiency chlorosis (2022) - Miranda

Objectives of the research: The objective is to screen all private company varieties that have been entered into the Langdon Research and Extension Center (REC), Carrington REC, Minot REC, Williston REC and Fargo Main Station yield trials for visual ratings of IDC at multiple field locations with a past history of IDC symptoms. A second objective is to provide visual IDC screening of approximately 100 advanced NDSU breeding lines. Soybean growers need information to aid them in comparing varieties from many different companies for iron-deficiency chlorosis (IDC) in side-by-side comparisons. This data provides unbiased information that enables growers to choose the best variety for their IDC prone fields.

Completed work: Hill plots were planted at two locations with a past history of IDC. One location was lost due to lack of IDC symptoms. Iron-deficiency chlorosis was observed at remaining site and IDC scores were taken at 3 different time points, two weeks apart. Two-hundred and thirty six Roundup Ready® and Xtend soybean varieties were evaluated for visual symptoms of IDC at one site where IDC was present. This is an increase in entries from 2021. Twenty nine Liberty Link or non-GMO cultivars were evaluated for IDC at one site where IDC was present which is the same amount as 2021. Seventy experimental lines or released cultivars that had been developed at NDSU were evaluated for visual IDC score. Each genotype was evaluated at three different growth stages on a 1-5 scale. At each site there were four replicates. Iron-deficiency chlorosis was evaluated at about the V3-V4 stage and again at the R1-R2 stage. The data was averaged across both of these rating growth stages. The data was of very good quality. The results were published online at https://www.ag.ndsu.edu/varietytrials/soybean and will be printed in the Soybean Variety Trials bulletin A-843.

Preliminary results: The data was of good quality and the known check varieties performed as expected.

In addition, the NDSU advanced lines were genotyped for IDC markers developed by Phil McClean at NDSU. These data still need to be analyzed in more detail, but preliminary analysis suggests that IDC tolerance is genetically fixed in a large majority of the NDSU lines developed from 2018. These markers will allow the breeding program to ensure that the genetic mechanisms that control IDC tolerance will continue to be selected for and carried on in future years. A publication about validation of these IDC markers in the NDSU breeding program is anticipated in 2023.

Work to be completed: This project is completed for the 2022 growing season. We have prepared an easier to use online application system for the 2023 season. Private companies will submit varieties into the state yield trials at any location in the state, seed of these will be packaged in preparation for planting in May or June of 2023. These entries will then be scored for visual IDC symptoms in June and July of 2023.

Update:
Visual rating for iron-deficiency chlorosis
Final Report June 2023
PI: Carrie Miranda

Objectives of the research: The objective is to screen all private company varieties that have been entered into the Langdon Research and Extension Center (REC), Carrington REC, Minot REC, Williston REC and Fargo Main Station yield trials for visual ratings of iron deficiency chlorosis (IDC) at multiple field locations with a past history of IDC symptoms. A second objective is to provide visual IDC screening of approximately 100 advanced NDSU breeding lines. Soybean growers need information to aid them in comparing varieties from many different companies for iron-deficiency chlorosis (IDC) in side-by-side comparisons. This data provides unbiased information that enables growers to choose the best variety for their IDC prone fields.

In July 2022, 157 GMO and 28 conventional private company varieties were tested in fields with previous IDC fields. One location was in Leonard and the other was at Colfax. Unfortunately, the Colfax location did not emerge and show IDC symptoms so that location was discarded. The Leonard location displayed ideal locations however the IDC symptoms were much stronger than in previous years and most lines performed poorly even with known IDC tolerance.

Three IDC scores were taken 1 month after planting, 2 weeks later, and 2 weeks after that. Scores were averaged and statistically analyzed using ANOVA. Results were reported in the A-843 bulletin and online in August 2022. The pdf of results is attached as a file in this report.

In the 2023 season, 193 GMO and 21 conventional private company varieties were entered for testing. To mitigate the risk of having only one useful field as in 2022 and additional field in Amenia was found and is being used. Planting was successfully completed in early June. Currently fields are being maintained weed free before the first IDC score can be taken.

Very gratefully, the soybean council recommended Dr. Jay Goos to consult with this project. He recommended to change our current testing plan to include more locations. First is to include three locations with previous season IDC symptoms as we are doing now. Then to wait until growers plant and see IDC symptoms in their field that year, locate an additional two locations, till, and plant our experiment exactly where the symptoms were seen. To mitigate the work of the extra locations he said we can do just two IDC scores instead of three. This is all profoundly useful advice and I am very grateful to have Dr. Goos on our IDC team even though he’s retired. This will ensure consistent useful data in following years.

View uploaded report 2

View uploaded report 3

In July 2022, 157 GMO and 28 conventional private company varieties were tested in fields with previous iron deficiency chlorosis (IDC) fields. One location was in Leonard and the other was at Colfax. Unfortunately, the Colfax location did not emerge and show IDC symptoms so that location was discarded. The Leonard location displayed ideal locations however the IDC symptoms were much stronger than in previous years and most lines performed poorly even with known IDC tolerance. The results of the IDC scores was published in August online at https://www.ag.ndsu.edu/varietytrials/fargo-main-station/2022-trial-results/2022-ndsu-enlist-gt27-rr-and-xtend-soybean-iron-deficiency-chlorosis-trial/view and https://www.ag.ndsu.edu/varietytrials/fargo-main-station/2022-trial-results/2022-ndsu-conventional-soybean-iron-deficiency-chlorosis-trial/view.
In the 2023 season, 193 GMO and 21 conventional private company varieties were entered for testing. To mitigate the risk of having only one useful field as in 2022 and additional field in Amenia was found and is being used. Planting was successfully completed in early June. Currently fields are being maintained weed free before the first IDC score can be taken.
We are very grateful to have Dr. Jay Goos consulting on this project. He has given us valuable advice to ensure we have multiple locations of useful data so that North Dakota farmers can make the right decisions for their fields.

This data will provide an independent confirmation of the IDC tolerance of company products and enable growers to compare varieties from many different companies with all of those varieties evaluated at the same locations. Comparing soybean varieties from different companies requires that the varieties of all companies are evaluated, averaged across the same fields, otherwise a fair comparison is not possible. This data enables growers to increase their yield on their IDC prone fields because those varieties with the least amount of yellow IDC symptoms will yield the best on those fields that have that problem.