Evaluation of gamma-linolenic acid composition of evening primrose (Oenothera) species native to Texas

Abstract

The oil of evening primrose (Oenothera sp.) is an important source of gamma- linolenic acid (GLA). GLA [C18:3Δ6,9,12] is an unsaturated fatty acid in demand for its nutritional and pharmaceutical application. Oenothera biennis L. is the primary commercial source of evening primrose oil. A study was conducted to determine if species of Oenothera, adapted to Texas, produce GLA levels comparable to O. biennis. This project identified and evaluated the fatty acid composition of eight species of evening primrose native to Texas. GLA levels of 54 accessions evaluated from collected seed ranged from 0.0% to 11.0%. Field experiments were then conducted to determine oil content, fatty acid composition, seed yield, and potential adaptation to commercial production of selected accessions. Mean GLA levels of cultivated seed from these accessions ranged from 0.0% to 10.1%. Mean seed oil content ranged from 7.3% to 21.7%. Of the species examined, O. elata subsp. hirsutissima (A. Gray ex S. Watson) W. Dietrich and O. jamesii (Torrey & Gray) demonstrated GLA levels and seed yields adequate for commercial production. Based on these results, O. elata subsp. hirsutissima and O. jamesii demonstrated sufficiently high GLA levels, oil content, and seed yields to be considered for commercial production.