2015
Evaluation of South Carolina soybean breeding lines
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Contributor/Checkoff:
South Carolina Soybean Board
Category:
Sustainable Production
Keywords:
GeneticsGenomics
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Benjamin Fallen, Clemson University
Co-Principal Investigators:
Project Code:
Contributing Organization (Checkoff):
South Carolina Soybean Board
(n/a)
Institution Funded:
Clemson University
(n/a)
Brief Project Summary:

The primary objective of the Clemson University Soybean Breeding Program is to release high-yielding soybean varieties that are well adapted to the environmental conditions and biotic stresses throughout South Carolina. To do this, research focuses on incorporating genetic diversity to broaden and improve sources of pest resistance, seed composition and yield in soybean, using molecular markers to improve selection for important agronomic traits and releasing varieties and germplasm adapted to the southeast. Key areas of focus include reniform nematode resistance, drought tolerance, rust resistance, resistance to other nematodes, new herbicide resistant traits as they become available and disease resistance. Other efforts focus on selection and identification of soybean genes controlling protein synthesis and storage along with the development of markers for those genes.

Key Benefactors:
farmers, agronomists, extension agents, soybean breeders, seed companies

Information And Results
Final Project Results

Objective 1: Project Title: Develop new seeding-rate recommendations and determine cost-effective seeding populations for South Dakota soybean growers. The advent of biotechnology has led to an increased interest from crop growers in the associated costs of this new biotechnology since much of it will be delivered to the field via biotech seed. Consequently, soybean growers have become increasingly interested in knowing the lower limits of plant population or density following emergence that will reduce seed costs without resulting in a significant reduction in yield and profits.
The SDSU Crop Performance Testing Program has conducted a study from 2009 to 2012 to determine if there is a lower limit that growers can use without suffering a significant reduction in yield. In the study, the plots were seeded in 8- and 30-inch rows. The range in seeding populations differed between the row-space treatments imposed. The six target seeding densities for the 8-inch rows ranged from 75,000 (75K) to 200,000 (200K), in 25,000 increments. In contrast, the six target seeding densities for the 30-inch rows ranged from 50,000 (50K) to 175,000 (175K), again in 25,000 increments.
Three trials were initiated at Brown County, Brookings, and at Beresford. The yield response to changing plant densities when planted in 8-inch rows were quite variable over locations, years, and maturity group (MG-0, -I, and ?II). Over three years (2009 to 2011) the highest yield for the MG-0, -I, and ?II soybeans were 61, 66, and 67 bu. /acre, respectively.
In MG-0 soybeans, a 22% reduction in density from 200 to 157K PPA reduced yield to 58 bu. /acre or 5%. A In MG-I soybeans, a 19% reduction in density from 200 to 162K PPA reduced yield to 63 bu. /acre or 5%. In MG-II soybeans, a 17% reduction in density from 200 to 166K PPA reduced yield to 64 bu. /acre or 5%. Similarly, from 2009 to 2011, a 35% reduction in density from 200 to 129K PPA reduced yield to 55 bu. /acre or 10% in the MG-0 soybeans. Likewise, a 34% reduction in density from 200 to 132K PPA reduced yield to 59 bu. /acre or 10% in the MG-I soybeans. In turn, a 36% reduction in density from 200 to 128K PPA reduced to 61 bu. /acre or 10% in the MG-II soybeans. When averaged over all locations, years, and MGs, the highest yields for 8-inch rows were obtained at densities near 200K PPA. A 5% yield reduction was obtained at densities near 161K PPA. In turn, a yield reduction of 10% was obtained at plant densities near 130K PPA.
The yield response to changing plant densities when planted in 30-inch rows were again quite variable over locations, years, and maturity group (MG-0, -I, and ?II). Over three years (2009 to 2011) the highest yield for the MG-0, -I, and -II soybeans were 54, 58, and 60 bu. /acre, respectively. A 15% reduction in density from 175 to 148K PPA reduced to 52 bu. /acre or 5% in the MG-0 soybeans. In turn, a 21% reduction in density from 175 to 139K PPA reduced yield to 55 bu. /acre or 5% in the MG-I soybeans. Likewise, an 18% reduction in density from 175 to 144K PPA reduced to 57 bu. /acre or 5% in the MG-II soybeans. Similarly, from 2009 to 2011, a 35% reduction from 175 to 113K PPA in 30-inch rows reduced yield to 49 bu./acre or 10% in the MG-0 soybeans. Likewise, a 45% reduction from 175 to 96K PPA reduced yield to 52 bu./acre or 10% in the MG-I soybeans. In turn, a 42% reduction from 175 to 101K PPA reduced yield to 54 bu./acre or 10% in the MG-II soybeans. When averaged over all MGs, the highest yields for 30-inch rows were obtained at densities near 175K PPA. A 5% yield loss occurred when plant densities decreased to 143K PPA. In turn, yields losses of 10% occurred as plant densities decreased to about 103K PPA.

Objective 3: results missing. Objective 4: On-farm studies. Results missing. Objective 5: Assess the impact of weeds and timing on soybean yields and gene expression. Results missing. Objective 6: Yield limiting factors in soybeans. Results missing. Objective 7: the results provided a baseline for future study. Objective 8: Energy and Carbon budgets. results missing.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.