Characterization of Vernonia galamensis germplasm for seed oil content, fatty acid composition, seed weight, and chromosome number

Abstract

Vernonia galamensis (Cass.) Less. has potential for domestication as a new industrial oilseed source of natural epoxy fatty acids. Thirty-four accessions from the six subspecies of the Vernonia galamensis complex were characterized for seed weight, seed oil content, and fatty acid composition. The mean seed weight of the six subspecies was 3.42 g/1000 seeds, with a range of 2.46 g to 5.43 g for ssp. mutomensis and ssp. afromontana, respectively. The mean seed oil content for the six subspecies was 30.8%, ranging from 25.1% to 39.2% for ssp. mutomoensis and ssp. lushotoensis, respectively. The 18:1 epoxy fatty acid (vernolic acid) was predominant. The mean vernolic acid content for the six subspecies was 72.5%, and ranged from 66.9% to 76.6% for ssp. mutomoensis and ssp. lushotoensis, respectively. Within the four varieties of ssp. galamensis, in which most of the current domestication effort is centered, oil contents ranged from 31.8% to 38.4%, and 18:1 epoxy fatty acid ranged from 68.0% to 77.0%. Mean levels of other fatty acids within the species were about 14% for linoleic acid (18:2), 7% for oleic acid (18:1), and from 2 to 3% for both palmitic acid (16:0) and stearic acid (18:0). The basic chromosome number for Vernonia galamensis was found to be n = 9. It was concluded that selection for improved levels of both oil and vernolic acid contents should be possible within a germplasm enhancement and plant breeding program.