Soybean [Glycine max (L.) Merr.] oil with oleic acid (18:1) content >500 g kg−1 is desirable for a broader role in food and industrial uses. Seed oil in commercially grown soybean genotypes averages about 230 g kg−1 oleic acid. Some maturity group (MG) II to V plant introductions (PIs) have elevated oleic concentrations of 300 to 500 g kg−1 Temperature of the growing environment during the reproductive growth stage affects oleic concentration in soybean oil. The objective of this study was to evaluate stability of oleic acid content among 15 PIs with elevated 18:1 and three checks grown in 16 environments. Oleic acid concentration of the high 18:1 checks N98‐4445A and M23 ranged from 383 to 694 g kg−1 and 428 to 572 g kg−1 with averages of 575 g kg−1 and 508 g kg−1, respectively. The PIs with the highest 18:1 were MG II to III, with most lines averaging >400 g kg−1 oleic acid concentration over 16 environments. Generally, PIs in MG II to III were less stable across environments than those in MG V. However, MG III PI 379559D ranged from 381 to 513 g kg−1 with an average 439 g kg−1 oleic acid concentration and was the most stable in oleic acid content of the 15 PIs studied. PI379559D was more stable than N98‐4445A or M23. PI417360 and PI506852 averaged highest in 18:1 (>330 g kg−1) among MG V PIs studied. Combining genes from these PIs and other sources with elevated 18:1 may be useful in developing higher oleic acid soybean genotypes.

Interest in soybean [Glycine max (L.) Merr.] isoflavones has increased in recent years owing to numerous reported health benefits. Consequently, quantitative trait loci (QTL) detection for marker‐assisted breeding for isoflavones is being examined for genetic gains. This study sought to detect QTL for soybean isoflavones in a population of 274 recombinant inbred lines derived from a cross between ‘Essex’ and ‘Williams 82’ that were subdivided and tested by maturity (early, mid, and late). The field tests were conducted in three environments in 2009 (Knoxville, TN; Harrisburg, IL; and Stuttgart, AR). The population was genotyped with 480 polymorphic single nucleotide polymorphism markers. Isoflavones for each replicate were analyzed by near infrared reflectance spectroscopy, whose prediction equation was based on high performance liquid chromatography. Each maturity test, containing 91 or 92 recombinant inbred lines, was analyzed separately for QTL. In total, 21 QTL were detected: 7 for genistein (chromosomes 5, 6, 9, 13, 17, and 19), 5 for daidzein (chromosomes 5, 6, 9, 13, and 19), 3 for glycitein (chromosomes 6, 9, and 20), and 6 for total isoflavone content (chromosomes 5, 6, 9, 13, and 19). Of these 21 QTL, 12 were confirmed or positional confirmations from other studies. Utilization of these QTL could potentially lead to marker‐assisted selection approaches for genetic gains in improving soybean isoflavones.