Genetic improvement of US soybean in maturity groups V, VI, and VII

Authors: BOEHM JR., JEFFERY - University Of Georgia; Abdel-Haleem, Hussein; SCHAPAUGH JR., WILLIAM - Kansas State University; RAINEY, KATY - Purdue University; PANTALONE, VINCENT - University Of Tennessee; SHANNON, GROVER - University Of Missouri; KLEIN, JIM - Southern Illinois University; Carter Jr, Thomas; CARDINAL, ANDREA - Syngenta Seeds, Inc; SHIPE, EMERSON - Clemson University; Gillen, Anne; CHEN, PENGYIN - University Of Mississippi; Smith, James - Rusty; WEAVER, DAVID - Auburn University; BOERMA, ROGER - University Of Georgia; LI, ZENGLU - University Of Georgia

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/23/2019
Publication Date: 9/5/2019
Publication URL: https://handle.nal.usda.gov/10113/6771636
Citation: Boehm Jr., J., Abdel-Haleem, H.A., Schapaugh Jr., W., Rainey, K., Pantalone, V.R., Shannon, G., Klein, J., Carter Jr, T.E., Cardinal, A.J., Shipe, E.R., Gillen, A.M., Chen, P., Smith, J.R., Weaver, D.B., Boerma, R., Li, Z. 2019. Genetic improvement of US soybean in maturity groups V, VI, and VII. Crop Science. 59(5):1838-1852. https://doi.org/10.2135/cropsci2018.10.0627.
DOI: https://doi.org/10.2135/cropsci2018.10.0627

Interpretive Summary: Soybean is an important source of protein and vegetable oil. Genetic improvement of soybean yield and seed composition is an ultimate breeding goal. Over past 80 years, breeders have worked diligently to select for high yield and other desired traits over time to make genetic improvements. The objectives of the present study were to evaluate 93 soybean cultivars selected from Maturity Groups (MG) V, VI, and VII that were released by breeders from 1928 – 2008 for genetic changes to seed yield, yield stability, and other important agronomic and end-use quality traits that may have occurred over an 80 yr period due to breeder selection. The results indicate that a yield plateau has not yet been reached in these southeastern soybean production areas. Furthermore, resistance to lodging improved by nearly a single lodging score point over eight decades within each MG.

Technical Abstract: Soybean [Glycine max (L.) Merr.] is an important source of protein and vegetable oil. Genetic improvement of soybean seed yield and composition are ultimate breeding goals. During the past 80 yr, breeders have selected for high yield and other desired traits to make genetic improvements. To quantify the genetic changes to seed yield, yield stability, and other important agronomic and end-use quality traits, we evaluated 93 soybean cultivars in Maturity Groups (MG) V, VI, and VII that were released from 1928 to 2008. Replicated yield trials specific for each MG set of cultivars were conducted during 2010 to 2011 in a total of 27 southeastern US year-location environments. A mixed linear model was used to calculate best linear unbiased predictors (BLUPs) for each cultivar for each measured trait within each MG. Regressed cultivar effect BLUPs of each trait by year of cultivar release revealed positive linear trends for annualized genetic yield gains of 17.6, 13.5, and 10.3 kg ha-1 yr-1 for MG V, VI, and VII, respectively. Averaged across MGs, the annualized rate of genetic gain was estimated to be 13.7 kg ha-1 yr-1. Yield stability analyses revealed significant differences in regression coefficients (b), which were >1.0 for newer cultivars but <1.0 for older cultivars. Overall, the average annualized rate of genetic gains for seed yield reported herein are equivalent to those previously reported, indicating that a yield plateau has not been reached for MG V, VI or VII soybean cultivars.