Evaluation of wild sunflower species for tocopherol content and composition

Abstract

SUMMARY Wild Helianthus species are an important reservoir of useful genes for sunflower breeding. The objective of the present research was to evaluate the existing variability for tocopherol content and composition in a germplasm collection of wild sunflower species. The germplasm evaluated consisted of 257 accessions from 36 Helianthus species, including both annual and perennial species. Eight seeds per accession were randomly picked and bulked for tocopherol analysis conducted by HPLC with fluorescence detection. Tocopherol content averaged 328 mg kg -1 seed in the analyzed accessions, with an average profile of 99.0% alpha-tocopherol, 0.7% beta-tocopherol, and 0.3% gammatocopherol. In cultivated material, an average tocopherol content of 669.1 mg kg -1 seed have been reported, made up of 92.4% alpha-tocopherol, 5.6% betatocopherol, and 2.0% gamma-tocopherol. The maximum total tocopherol content in wild sunflower germplasm corresponded to an accession of H. maximilianii, with 673 mg kg -1 seed. Increased levels of beta-tocopherol were identified in one accession of H. praecox (11.2% of the total tocopherols) and one accession of H. debilis (11.8%). All other accessions contained less than 6.5% betatocopherol. Increased gamma-tocopherol levels were identified in one accession of H. exilis (7.4%) and two accessions of H. nutalii (11.0% and 14.6%, respectively). All other accessions contained less than 2% gamma-tocopherol. Although further research at an intrapopulation level is needed to confirm and isolate variants, the results of the present research indicated that wild Helianthus germplasm contains useful variability for tocopherol content and composition.