Fifty years of collecting wild Helianthus species for cultivated sunflower improvement

Authors: Seiler, Gerald; MAREK, LAURA - Iowa State University; GULYA, THOMAS - Retired ARS Employee

Submitted to: Sunflower International Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/20/2022
Publication Date: 6/20/2022
Citation: Seiler, G.J., Marek, L.F., Gulya, T. 2022. Fifty years of collecting wild Helianthus species for cultivated sunflower improvement. In: Proceeding of the 20th International Sunflower Conference, June 20-23, 2022, Novi Sad, Serbia. p.197-200.

Interpretive Summary: One of the missions of the USDA is to collect and preserve wild relatives of crop species for crop improvement. Given the tenuous situation of wild sunflower species in nature, seed banks may provide the only way to preserve them for posterity. Since the sunflower crop wild relatives (CWR) are native to North America, this has provided an opportunity to collect and preserve them in gene banks for current and future use. The sunflower CWR have evolved where they are adapted to a wide range of diverse habitats, developing resistance to various pests and abiotic stress that offers sunflower breeders the opportunity to use potentially useful traits for sunflower improvement. Over the last half century, the USDA, National Plant Germplasm System (NPGS) has undertaken 32 explorations covering over 200,000 miles to collect samples of the various wild species in the conterminous US and Canada. This has resulted in a gene bank collection at the USDA, NPGS, North Central Regional Plant Introduction Station, Ames, Iowa that contains 2,591 active accessions of 53 annual and perennial species. This collection is the largest and most genetically diverse ex situ sunflower collection in the world and is vital to the conservation of wild sunflower species for the global sunflower community, preserving them for future generations.

Technical Abstract: Wild Helianthus species have been undeniably beneficial in sustaining the sunflower crop by providing plant breeders with a diverse genetic pool of potentially useful traits. Exploration to collect populations of wild sunflowers is one of the more difficult and challenging activities in the conservation and utilization of these valuable genetic resources. The logistics of collecting requires careful planning, locating the target species, obtaining permission to access and collect, and timing the exploration to ensure the availability of mature seed. The U.S. Department of Agriculture, Agricultural Research Service established the wild Helianthus seed collection in 1976 with the goal of collecting and conserving the broadest representative genetic diversity possible, serving as a central repository of germplasm and related information. Over the last half century, 32 explorations were undertaken covering 125,000 km to collect the 53 Helianthus species from their distributional ranges in the forty-eight conterminous states in the USA. One exploration was undertaken in the Prairie Provinces of Canada. Additionally, naturalized Helianthus species have been collected in Australia. The exploration collecting the most accessions occurred in 1980 in the USA when representative populations of 33 species from 20 southwestern and southeastern states were sampled over a two-and-a-half-month period jointly with an international collaborator. This collection trip added over 380 accessions to the USDA wild species gene bank collection. The many explorations have added over 2,590 accessions to the USDA wild species gene bank collection. The current wild sunflower gene bank collection at the USDA, ARS, North Central Regional Plant 6.Introduction Station (NCRPIS), Ames, Iowa contains 2,591 active accessions of 53 species with 1,056 wild H. annuus accessions (41%), 636 accessions representing populations of 13 other wild annual species (24%), and 899 accessions representing 39 perennial species (35%). This collection is the largest and most genetically diverse ex situ sunflower collection in the world and is vital to the conservation of wild sunflower species for the global sunflower community.