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ARS Home » Midwest Area » Urbana, Illinois » Soybean/maize Germplasm, Pathology, and Genetics Research » Research » Publications at this Location » Publication #298791
Title: Genetic improvement of U.S. soybean in Maturity Groups II, III, and IV

Author
item RINCKER, KEITH - University Of Illinois
item Nelson, Randall
item SPECHT, JAMES - University Of Nebraska
item SLEPER, DAVID - University Of Missouri
item CARY, TROY - University Of Illinois
item CIANZIO, SILVIA - Iowa State University
item CASTEEL, SHAUN - Purdue University
item CONLEY, SHAWN - University Of Wisconsin
item Mian, Rouf
item DIERS, BRIAN - University Of Illinois

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/6/2014
Publication Date: 4/28/2015
Publication URL: http://handle.nal.usda.gov/10113/61840
Citation: Rincker, K., Nelson, R.L., Specht, J., Sleper, D., Cary, T., Cianzio, S., Casteel, S., Conley, S., Chen, P., Davis, V., Fox, C., Graef, G., Godsey, C., Holshouser, D., Jiang, G., Kantartzi, S., Kenworthy, W ., Lee, C., Mian, R.M., McHale, L., Naeve, S., Orf, J., Poysa, V., Schapaugh, W., Shannon, G., Uniatowski, R., Wang, D., Diers, B. 2015. Genetic improvement of U.S. soybean in Maturity Groups II, III, and IV. Crop Science. 54:1419-1432. doi: 10.2135/cropsci2013.10.0665.

Interpretive Summary: In the U.S., soybean breeding began in the 1930's. The purpose of this research was to evaluate the changes in soybean varieties that have occurred over the past 80 years by evaluating 168 soybean varieties in over 25 environments. These varieties are in maturity group II, III, and IV and were released between 1923 and 2008. We found that averaged over the entire period genetic improvement in yield has averaged approximately one third of a bushel per acre per year. However a more detailed statistical analysis showed a change in the rate of gain in more recent years and yield is now increasing at 0.4 bushels per acre per year. Newer cultivars always yielded more than the older cultivars and that difference was greatest in the highest yielding environments. Newer cultivars are shorter, mature later, lodge less, and have seeds with less protein and greater oil concentration. Comparing these data and long term production records indicates that most of the yield increases realized over the past 80 years are the result of genetic improvements. These results will be of interest to anyone concerned about soybean yield.

Technical Abstract: Soybean [Glycine max (L.) Merr.] improvement via plant breeding has been critical for the success of the crop. The objective of this study was to quantify genetic change in yield and other traits that occurred over the past 80 years of North American soybean breeding in maturity groups (MGs) II, III, and IV. Historic sets of 60 MG II, 59 MG III, or 49 MG IV soybean cultivars, released from 1923 to 2008, were evaluated in MG-specific field trials conducted in 17 states and one Canadian province during 2010-11. Averaged over ca. 27 site-years of data, the estimated rates of breeding-mediated yield improvement during the 80 years were 23 kg ha-1 yr-1 for MG II and III, and 20 kg ha-1 yr-1 for MG IV. However, a 2-segment linear regression model provided a better fit to the data and indicated that the average current rate of genetic yield gain across MG is 29 kg ha-1 yr-1. Modern cultivars yielded more than old cultivars in all environments, even more so in high yielding environments, which is indicative of a synergistic interaction between genetic-based and agronomic-based yield improvement. New cultivars in the historic sets are shorter, mature later, lodge less, and have seeds with less protein and greater oil concentration. Given the current genetic yield improvement rate of 29 kg ha-1 yr-1, one can infer that continual release of ever higher yielding cultivars has been a substantive driver of the USA on-farm realized yields of 29 kg ha-1 yr-1.