Submitted to: Plant Species Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 9, 2011
Publication Date: May 1, 2012
Citation: Swoboda, K.A., Cane, J.H. 2012. Breeding biology and incremental benefits of outcrossing for the restoration wildflower, Hedysarum boreale (Fabaceae). Plant Species Biology. 27(2): 138-46. Interpretive Summary: Northern sweetvetch, Hedysarum boreale, is a pink flowered herbaceous legume found throughout the Rocky Mountains, from high in subalpine habitats down to dry sagebrush canyons. Private growers are producing its seed for restoration applications, particularly on public lands and highway right-of-ways. We evaluated the pollination needs of sweetvetch, finding that it requires bees for fruit and seed set. The species proved to be self fertile, although more mature and germinable seed does result from crossing between plants. Like alfalfa and many other cultivated legumes, fruit set maximized at about 50% even with thorough bee pollination. The mechanics of the floral stigma that apparently prevent autopollination in the bud also necessitate several bees visits to realize pollination potential.
Technical Abstract: Northern sweetvetch, Hedysarum boreale, is an herbaceous perennial of the Rocky Mountains whose seed is desired for rehabilitating degraded plant communities. Through experimental manual pollinations, the necessity of pollinators was shown by the failures of autopollination and wind pollination, even though its stigmas, like those of soybean and common bean, first becoming receptive in the bud amid the dehiscing anthers. The species proved to be self-fertile, initiating as many fruits through selfing as outcrossing either within or between populations. Incremental outcrossing benefits only later manifested in superior fruit development, seed maturation and seed germination. Farming of H. boreale can yield abundant viable seed if adequately visited by pollinating bees.