The use of soybean [Glycine max (L.) Merrill] is widespread, with applications in food, fuel, livestock feed, and industrial products. We developed a soybean population of 239 F 4 -derived recombinant inbred lines (RIL) from the cross "5601T" × U99-310255 to estimate the heritability and genetic gain for seed protein, oil, and yield, and to assess the utility of making selections for these important traits. Heritability estimates on an entry means basis for protein (0.78), oil (0.65), seed yield (0.38) varied by trait with regard to genetic influence. Genetic gain was calculated for each trait at 5%, 10%, 15%, and 20% selection intensities. With the genetic gain that was obtained through the selections for each trait, some lines excelled above that of the checks and parents in this population. The second and third highest yielding selections (56U99-081 and 56U99-244) are notable in producing 50.2% and 49.8% meal protein, respectively, while maintain high yields above the high-yielding parent, 5601T. Seeking balance for these important soybean traits is essential for breeders looking to make optimal improvements for the wide variety of soybean uses. Further research on this population could prove to be of value to breeding programs wishing to increase seed yield, oil, and protein.

Phytate (myoinositol‐1,2,3,4,5,6‐hexa‐kisphosphate) in soybean (Glycine max (L.) Merr.) cannot be absorbed by livestock with monogastric digestive systems, and is often excreted in their waste. This can result in agricultural runoff pollution, as well as nutritional deficiencies in poultry (Gallus Gallus domesticus) and swine (Sus domesticus). The enzyme phytase is often applied to break the phytin‐salt bonds and allow for phosphorus (P) absorption, but is an added cost for animal producers. Therefore, we developed a low‐phytate BC4‐derived line TN09‐239 for comparison of agronomic and seed‐quality traits with the high‐yielding recurrent parent, 5601T. In a replicated, multienvironment field test in Tennessee, TN09‐239 was significantly higher for inorganic P (Pi) (P < 0.001), which is inversely correlated with the seed‐phytate concentration, but significantly lower for yield (P < 0.05) in comparison with the recurrent parent. These findings for increased Pi, but reduced yield, for TN09‐239 in comparison with 5601T were confirmed in the 2010 United States Department of Agriculture (USDA) Uniform Preliminary V Soybean Test grown in 10 southern US environments. 5601T and TN09‐239 differed in Pi stability across southern environments, with linear regression showing 5601T having stability across environments, while TN09‐239 showed variations based on the environments. However, in each environment TN09‐239 displayed nearly a 10‐fold increase in Pi compared to 5601T. Although the low‐phytate trait and much of the recurrent parent genome along with 85–90% of the yield have been captured, further backcrossing could help recover the remaining seed yield of 5601T and other traits desirable for southern US producers.