ARS | Publication request: BEE ASSOCIATES OF FLOWERING ASTRAGALUS AND ONOBRYCHIS GENEBANK ACCESSIONS AT A SNAKE RIVER SITE IN EASTERN WASHINGTON

Submitted to: Journal of Kansas Entomological Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 15, 2005
Publication Date: August 1, 2006
Citation: Clement, S.L., Griswold, T.L., Rust, R.W., Hellier, B.C., Stout, D.M. 2006. Bee associates of flowering Astragalus and Onobrychis genebank accessions at a Snake River site in Eastern Washington. Journal of Kansas Entomological Society. 79(3):254-260.

Interpretive Summary: The USDA-ARS Western Regional Plant Introduction Station is responsible for maintaining over 72,000 accessions of crop plant taxa that are important for sustaining American agriculture. Seed of these accessions are held in a cold storage facility (seedbank) in Pullman, Washington and are acquired by plant breeders and other scientists for crop improvement programs in the U.S. and abroad. Curators establish seed-regeneration field nurseries to replenish seed stocks low in supply in the Pullman seedbank. This paper reports research that found 52 species of pollinating bees in these nurseries, an important finding because these bees can effect inter-accession outcrossing and thus compromise the genetic integrity of the cross-pollinated accessions in these nurseries. This research supported a decision by Pullman curators to forego the use of open pollinated field nurseries to re-generate seed of bee mediated cross-pollinated accessions. The preferred method for multiplying seed of these accessions is to cage plants with suitable insect pollinators, thus maintaining the genetic integrity of individual accessions.

Technical Abstract: Technical Abstract: A 3 year survey of the bee associates of flowering accessions of Astragalus and Onobrychis species was conducted in open-pollinated field nurseries at Central Ferry, Washington to gain insight into the potential for bee-mediated inter-accession out-crossing in these nurseries. Such nurseries are used by genebank managers at the USDA-ARS Western Regional Plant Introduction Station (WRPIS), Pullman, Washington, to multiply seed of accessions low in viability and/or supply. Fifty-two species of bees (Hymenoptera) in the Andrenidae (4 species), Apidae (18), Colletidae (1), Halictidae (5), and Megachilidae (24) were recorded. Species-rich genera were Bombus (8 species) and Osmia (16). One undescribed species of Osmia was collected. The bee fauna was more diverse on Astragalus (45 bee species) compared to Onobrychis (29 species). Among the 24 Astragalus and 13 Onobrychis species censused, bee diversity was highest on A. bungeanus Boiss. (24 bee species), A. chaborasicus Boiss. & Hausskn. (24 species), A. miser var. serotinus (A. Gray ex J.G. Cooper) Barney (14 species), A. cicer L. (13 species), A. schistosus Boiss. & Hohen. (12 species), A. onobrychis L. (11 species), A. podolobus Boiss. & Hohen. (11 species), and Onobrychis viciifolia Scop. (10 species). The presence of a rich bee fauna in WRPIS nurseries at Central Ferry, including documented pollinators of the allogamous species A. cicer and O. viciifolia, could complicate efforts to prevent hybridization and maintain genetic integrity of genebank accessions of allogamous plant species. Our results supported a 1993 decision by WRPIS curators to discontinue the practice of clustering accessions of single species of Astragalus and Onobrychis in open-pollinated nurseries to regenerate seed.