|MAREK, LAURA - Iowa State University|
Submitted to: Crop Science
Publication Type: Review Article
Publication Acceptance Date: 10/12/2016
Publication Date: 2/9/2017
Citation: Seiler, G.J., Qi, L.L., Marek, L.F. 2017. Utilization of sunflower crop wild relatives for cultivated sunflower improvement. Crop Science. 57:1-19. https://doi.org/10.2135/cropsci2016.10.0856.
Interpretive Summary: Sunflower is one of the few crops native to the U.S. Its domestication dates back to 4625 B.P. in the eastern U.S., in the Mississippi River Valley in the vicinity of present-day Arkansas. The estimated world production of sunflower in 2014 was 61 million acres in 72 different countries; it is grown on every continent except Antarctica. The sunflower crop has a very narrow genetic base putting it at risk of a disaster as happened in corn in the late 1970s with leaf blight. Crop wild relatives of sunflower also evolved in the U.S. where they adapted to a wide range of diverse habitats, developing resistance to various pests and abiotic stress that offers us the opportunity to use them for the improvement of the sunflower crop. The current U.S. Department of Agriculture, Agricultural Research Service, National Plant Germplasm System crop wild relatives sunflower collection is the largest extant collection in the world, containing 2,519 accessions comprising 53 species; 39 perennial and 14 annual. The estimated annual economic contribution of the wild species for cultivated sunflower is between $267 to $384 million USD annually. The majority of the value is derived from the PET1 cytoplasm from the wild prairie sunflower used in hybrid seed production, disease resistance genes for rust, downy mildew, powdery mildew, Verticillium wilt, Phomopsis stem canker, Sclerotinia wilt, select insects, abiotic salt tolerance, parasitic broomrape, select viruses, and resistance to imidazolinone and sulfonylurea herbicides. Crop wild relatives of sunflower have played a vital role in the development of a viable sunflower crop, and will continue to do so in the future as one of the primary sources of genetic diversity for the sunflower crop, contributing specific traits to combat emerging pests and environmental challenges and at the same time being preserved for future generations.
Technical Abstract: Sunflower (Helianthus annuus L.) is one of the few crops native to the U.S. The current USDA-ARS-NPGS crop wild relatives sunflower collection is the largest extant collection in the world, containing 2,519 accessions comprised of 53 species; 39 perennial and 14 annual. To fully utilize gene bank collections, however, researchers need more detailed information about the amount of and distribution of genetic diversity present within the collection. The wild species are adapted to a wide range of habitats and possess considerable variability for most biotic and abiotic traits. This represents a substantial amount of genetic diversity available for many agronomic traits for cultivated sunflower, which has a very narrow genetic base. Sunflower ranked fifth highest among 13 crops of major importance to global food security surveyed from the mid-1980s to 2005 in the use of traits from crop wild relatives. The estimated annual economic contribution of the wild species for cultivated sunflower is between $267 to $384 million USD. Most of the value is derived from the PET1 cytoplasm from wild H. petiolaris, disease resistance genes, abiotic salt tolerance, and resistance to imidazolinone and sulfonylurea herbicides. Crop wild relatives provide a wide range of valuable attributes for traditional and molecular breeding, as well as for ecological experimentation, and have enabled rapid advances in ecological and evolutionary genetics. The wild species of Helianthus continue to contribute specific traits to combat emerging pests and environmental challenges and at the same time are preserved for future generations.