Stability of Oleic Acid Content in Higher Oleic Soybean Plant Introductions.

Soybean [Glycine max (L.) Merr] seed oil generally contains oleic (220 g kg^-1) acids. Soybean oil with higher oleic (> 500 g kg^-1) and lower linolenic (< 30 g kg^-1) acids is desirable for improved functionality in food and industrial applications. Oleic acid content in soybean seed oil is affected by temperature during the reproductive growth stage. Thus, it is important to select high oleic genotypes in which oleic concentration is more stable across growing environments. The objective of this study was to determine the stability of oleic acid concentration across environments for 18 soybean genotypes including 15 high oleic plant introductions (PI) in maturity groups II - V and three checks.  Soybeans were planted 16 different environments across five locations during three years 2005-2007.
Generally, higher oleic acid PIs in early maturity groups (MG II-III) were less stable than the latest maturity group (MG V) across environments. Among the 15 PIs with the highest oleic acid concentration, all were group II-III and showed over 400 g kg^-1 oleic acid concentration across 16 environments. Oleic acid concentration of the high oleic checks N98-4445A and M23 ranged from 383-694 g kg^-1 with an average 575 g kg^-1 and 428-572 g kg^-1 with an average 508 g kg^-1, respectively. PI379559D (MG III) ranged from 381 to 513 g kg^-1 with an average 449 g kg^-1 oleic acid concentration. and was the most stable in oleic acid concentration of the 15 PIs studied.  PI379559D was more stable than N98-4445A, and showed similar stability to M23 which has been more stable than high oleic lines in other studies. Of the MG V PIs, PI417360 and PI506852 were highest in oleic acid concentration (>330 g kg^-1) across environments. Combining higher oleic acid genes from PIs and other sources could be useful to develop soybeans with higher oleic acid content.