Stability of fatty acid profile in soybean genotypes with modified seed oil composition

Genetic effects and temperature during the reproductive period for unsaturated fatty acids in soybean [Glycine max (L.) Merr.] seed oil affect oil composition. Increasing oleic and reducing linolenic acids are desirable to improve oil for food and other uses. The objective of this study was to access the environmental effect on fatty acids of seed oil for seventeen soybean genotypes with normal and modified fatty acid profiles. Stability coefficients (b values) were calculated from the regression of fatty acid level on average temperature over the final 30 d of the reproductive period across 10 environments. Mid-oleic acid genotypes were generally less stable for oleic acid content than genotypes with reduced oleic acid. Significant differences, however, were found for oleic acid stability among mid-oleic acid genotypes. Midoleic acid lines N98-4445A and N97-3363-4 were the most unstable among the 17 genotypes with stability coefficients of 3.28 and 2.53, respectively. However, the higher oleic acid line M23 was relatively stable in oleic acid with a stability coefficient of 0.13 over environments. IA 3017 at 10 g kg(-1) was the most stable in linolenic acid content across environments while progressively higher linolenic acid genotypes were less stable. Soybean lines similar to M23 and IA 3017 will be essential to develop increased oleic acid and reduced linolenic acid cultivars to ensure consistent production of soybean oil with the desired fatty acid levels.