Evaluation of Seeds of Sunflower Species for Several Chemical and Morphological Characteristics1

Abstract

The genus Helianthus contains 50 species representing much genetic diversity. Wild sunflower species are important sources of disease and insect resistance, but several species have not been evaluated for oil and fatty acid concentration and morphological characteristics of the seeds. Evaluation of seeds for these characteristics would give a better idea of the potential value of these species when used in a sunflower breeding program. One problem in evaluating oil and fatty acid concentrations is that it varies greatly depending on the environmental conditions under which it develops. Growing plants at a common location can reduce the environmental variation and give a better idea of the genetic control of oil and fatty acid concentrations. The objectives of this study were (i) to evaluate seeds of 24 annual and perennial species of Helianthus for oil and fatty acid concentrations and morphological characteristics and (ii) to compare the oil and fatty acid concentrations of seeds from 22 perennial species sampled in their native habitats with those from the same species grown at a common location. Helianthus anomalus Blake had the highest average seed weight (7.3 mg/seed) and also the highest average oil concentration (344 g kg−l). The commercial ‘Hybrid8 96’ had a seed weight of 37.3 mg/seed and oil concentration of 398 g kg−l. Linoleic acid concentrations ranged from a high of 832 g kg−l in one collection of H. porteri (A. Gray) Heiser to a low of 473 g kg−l in one collection of H. arizonensis R. Jackson. Linoleic acid concentrations in excess of 680 g kg−l were found in 16 of 24 species evaluated. Oleic acid concentrations ranged from 411 g kg−l in one collection of H. arizonensis to 55 g kg−l in one collection of H. porteri. Accessions of H. hirsutus Raf., H, silphioides Nutt., and H. atrorubens L. had an average oleic acid concentration above 450 g kg−l. Commercial Hybrid 896 had a linoleic and oleic acid concentration of 488 g kg−l and 395 g kg−l, respectively. Seeds of 7 of the 22 perennial species grown at a common location had significantly different oil concentrations than seed from the original habitats. Oleic acid concentrations changed significantly in different environments in 10 of the 22 species, and linoleic acid concentrations were significantly affected in 5 of the 22 species. The species examined appear to contain variability in chemical and morphological characteristics that could be useful for enhancing sunflower germplasm.