The grant would enable NDSU to continue the process of developing glyphosate-tolerant soybean cultivars. This project will significantly reduce seed costs to soybean growers and provide a mechanism for weed management. Glyphosate-tolerant experimental lines in the NDSU breeding program are being tested in a range of maturity that varies from MG 00.6-1.3, and are properly adapted throughout the entirety of North Dakota. New experimental lines are developed each year. NDSU has a very large breeding program devoted to development of glyphosate-tolerant cultivars and will continue to expand this year. This project is also working to acquire the glufosinate tolerant trait and breeding would be begin as soon as possible.

The objective is to continue the process of developing glyphosate-tolerant experimental lines with a goal of releasing additional cultivars of varying maturities that are developed by NDSU. In addition, other herbicide resistance traits are being explored to incorporate into this project.

The first high yielding glyphosate tolerant (GT) variety that is also tolerant to IDC and soybean cyst nematode is expected to be evaluated for release in 2022/ 2023. In addition, NDSU has released 4 GT varieties. In 2021, two new GT lines were released: ND21008GT20 and ND2108GT73. ND21008GT20 is an improvement on ND17009GT with increased IDC tolerance. ND2108GT73 is the first later maturing line at MG 0.8. This variety
allows NDSU soybean to be grown in new areas of the states and even in South Dakota, expanding the market area for NDSU. The first GT cultivar (ND17009GT) was released in January of 2017. ND17009GT is a 00.9 maturity, GT variety with high yield, excellent phytophthora root rot resistance that is moderately tolerant to IDC. ND18008GT is a 00.7 maturity, GT NDSU variety that was released in January of 2018. ND18008GT is resistant to soybean aphid, has an excellent gene for phytophthora root rot resistance, good IDC tolerance and lodging resistance as well as yield that is equal to a private-company RR2 variety. The NDSU Soybean Breeding
program has a past history of producing new cultivars that are very competitive with private company products.

Updated January 5, 2024:
Breeding of Glyphosate-Tolerant Soybean Cultivars (2023)- Miranda

Objectives of the research: The objective is to continue the process of developing glyphosate-tolerant experimental lines with a goal of releasing cultivars of varying maturities that are developed by NDSU.

Deliverables: Development of soybean cultivars for commercial release. Training graduate students to be skilled plant breeders.

Milestones: A complete field season is May-October. This includes planting in mid-May through early June. Fields are maintained weed free from planting until canopy closure in August. In-field crossing occurs in July. Maturity notes, plot evaluation, and line purification/roguing occur in September. Harvest is completed in October. Data evaluation is done immediately following harvest. Decisions/selections about planting the following season are done in November. Experiments are designed and envelopes printed in December and seed packing and cleaning occurs December-April.

Key performance indicators: The most important key performance indicator is the collection of useful data. It is not always possible to see yield and trait improvements every year, however if the data collected at harvest are useful and have low error, then the season is viewed as successful. In addition, the initiation of new populations creates new materials for the program. Successful crosses (F1s) are determined in October during harvest.

Completed work: The glyphosate tolerant program is half of the NDSU soybean breeding program in 2023. The first SCN resistant, glyphosate tolerant variety will be considered for prerelease in April 2024. 600 pounds of breeder seed of the potential cultivar was handed over to Foundation Seedstock in fall 2023 for foundation seed increase.

Sixteen glyphosate tolerant populations were initiated in the field in July 2023. Ten additional populations were created in the greenhouse using North Dakota by Nebraska or Illinois parents. All early generation seed is being advanced in the Costa Rica winter nursery to speed up generation advancement.

In an effort to reduce unfavorable phenotypes such as dark brown pod, long internode, and thin stem, heavy selection against those traits was performed on F5 plant rows. The glyphosate tolerant project is also being reduced as the program transitions to conventional germplasm with an herbicide trait introgression pipeline. Only 50 glyphosate tolerant plant rows are being tested in 2024 preliminary trials.

Yield data was considered useful for the season, with only one location being lost due to insufficient rainfall and late season weed pressure. Twenty five glyphosate tolerant lines will be tested in second year yield trials in 2024. Early maturing lines that are selected for advancement did not have a yield advantage compared to checks, but may have disease resistance improvement based on pedigree. Mid and late maturing lines showed a yield improvement compared to the mid maturing check.

Selections for 2024 third year yield trials were successful. Two lines were selected for advancement based on yield exceeding checks and stacked disease resistance including phytophthora and SCN resistance based on pedigree.

No new glyphosate tolerant line will be added into fourth year yield testing although the line being evaluated for prerelease will be tested for another year in this trial.

The season was considered successful due to quality of data at harvest. Early generation seed was created and is advancing in the Costa Rica winter nursery. During 2024 the program will begin transitioning to majority conventional germplasm and an herbicide trait introgression pipeline which will shrink the size of the glyphosate tolerant project. This will allow more resources to be available to improve yield and acquire newer herbicide technology.

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The intent is that growers will be able to reduce their input costs by purchasing high-yielding, very competitive, GT cultivars developed at NDSU. Monsanto has stated that starting in 2015 growers will be able to save their own seed for planting the following year. However, the private company cultivars are also protected under a Variety Patent. Varieties developed at NDSU are not patented. Currently, four GT varieties that were developed by NDSU are available to soybean growers. Continual yield and trait improvement is occurring within the program which includes introducing new materials from other successful breeding programs.