Updated July 18, 2022:
July 1, 2021 – June 30, 2022 Annual Report: Visual ratings for iron-deficiency chlorosis
Principal Investigator: Dr. Carrie Miranda, Department of Plant Sciences, North Dakota State University
Soybean growers with fields that have a past history of IDC, need information to aid them in comparing varieties from many different companies for iron-deficiency chlorosis (IDC) in side-by-side comparisons. There are genetic differences among cultivars for tolerance to IDC. We measure the tolerance to IDC by the amount of yellowing in the leaves at sites with a past history of IDC. Visual yellowing that is caused by IDC has been shown to be closely correlated to yield for fields that have IDC. This data provides unbiased information that enables growers to choose the best variety for their IDC prone fields. This data enabled growers to compare varieties from many different companies. Comparing soybean varieties from different companies requires that the varieties of both companies are evaluated, averaged across the same fields. Otherwise, a fair comparison is not possible.
The objective was to screen 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 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 advanced NDSU breeding lines.
In 2021, three locations on farmer-cooperator fields with a past history of IDC symptoms had been identified and were later planted with hill-plots. Unfortunately, one location had poor emergence and another did not show IDC symptoms, so data from only one location was utilized. There were 215 GMO company varieties tested and 38 Liberty Link and non-GMO company varieties tested. A total of 1,012 hill-plots were rated for IDC. Each hill was hand planted with eight seeds and later thinned to three seeds per hill to provide a uniform plant density. The sites were either sprayed with glyphosate or hoed to eliminate weeds.
Each hill was rated three different times at different soybean growth stages to record the visual IDC score at the three-leaf stage and later as the plants recover from the IDC symptoms. The rating scale is 1- green, 2- slight yellowing between leaf veins, 3- extensive yellowing, 4- growing point is dead, 5- plants are dead. Each hill is rated to the nearest one-half rating value. Also, the NDSU soybean breeder evaluated 113 advanced NDSU breeding lines for visual IDC symptoms.
The 2021 data was very good and the check varieties performed as expected. The extent of IDC symptoms at a specific site is dependent on having sufficient rainfall at early vegetative growth stages. Each variety was averaged across four replicates within each of the four sites. Data was analyzed and reported in the NDSU bulletin entitled ‘North Dakota Soybean Performance’ and was posted online.
This is the largest data set with the most comparisons of many different company varieties, both Roundup Ready, Liberty Link and non-GMO for North Dakota and western Minnesota. Because the data is averaged across three scoring dates and with four replications per location, the data is quite reliable in aiding growers to select the best varieties for their IDC prone fields. 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.
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July 1, 2021 – June 30, 2022
Final Project Results: Visual ratings for iron-deficiency chlorosis
Principal Investigator: Dr. Carrie Miranda, Department of Plant Sciences, North Dakota State University
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 all the different companies in the same locations. This proposal permitted 253 different GMO company varieties and non-GMO varieties to be evaluated for IDC tolerance. An additional 113 NDSU breeding lines were evaluated. All private company varieties that were entered into the Langdon Research and Extension Center (REC), Carrington REC, Minot REC, and Fargo Main Station yield trials were evaluated for visual ratings of IDC at multiple field locations. These data provided independent confirmation of the IDC tolerance of company products and enable growers to compare varieties from different companies. This project provides an unbiased comparison of yield data in the same environment for growers to select tolerant cultivars to increase yield on fields that have a past history of IDC.
In 2021, 215 GMO company varieties were tested and 38 Liberty Link and non-GMO company varieties were planted in three locations. Those locations included Leonard, Colfax, Erie, ND. One location successfully showed IDC symptoms and three scoring dates were recorded. Data was analyzed and reported in the NDSU bulletin entitled ‘North Dakota Soybean Performance’ and was posted online.
The goal of this work is to give growers additional data so they can make the best decisions when choosing varieties, especially on IDC affected soils. Support for this project is high among private companies as well, as 253 varieties were entered in 2021. Fields infected with IDC were selected for the 2022 season during 2021. Due to the usefulness of the data collected, this project will continue into 2022.