Desert Parsley (Lomatium spp.) Seed Production Challenges

About 80 species of desert parsleys (Lomatium spp.) are native to the western United States. They are important parts of the natural plant diversity and include edible and medicinal species. Mechanized cultivation and seed production technology is virtually unknown for these species. Fernleaf biscuitroot or fernleaf desert parsley (Lomatium dissectum) has been a specie of concern, since it has been dug for medicinal use without replacement. Commercial seed production is necessary to provide the quantity of seed needed for rangeland restoration efforts and any sustainable commercial root production activities. Over the last four years,  we have sought means to mechanically produce Lomatium and its seed at the Malheur Experiment Station in eastern Oregon.  Seed of Nineleaf desert parsley (L. triternatum), Gray's desert parsley (L. grayi), and fernleaf desert parsley (Lomatium dissectum) were drilled in rows 30 inches apart. The seed production response of desert parsley to irrigation was tested in 2006, 2007, and 2008. Irrigation treatments were applied to plots four rows wide and 30 feet long arranged in a randomized complete block design with four replicates. Irrigation was applied using drip tape installed at 12 inch depth between two rows of plants spaced 30 inches apart. The drip tapes were installed on alternating inter-row spaces (5 feet apart). Desert parsley was submitted to three irrigation rates: 0, 1, and 2 inches of water applied starting at the beginning of flowering four times for a total of 0, 4, and 8 inches/year.  Seed was harvested by hand. Mechanical combine harvest would have been possible if substantial development investment had been possible to reduce the ventilation and still separate seed from chaff. In 2007, seed yield for Gray's and nineleaf desert parsleys were low and increased with increasing water applied up to the highest amount evaluated, 8 inches. In 2008, seed yields showed a quadratic response to irrigation rate. Seed yields of nineleaf desert parsley were maximized by 8.4 inches of water applied. Seed yields of Gray's desert parsley were maximized by 6.9 inches of water applied in 2008.  While both of these species produced over 1000 lb/acre of seed in the fourth year, fernleaf desert parsley failed to prosper and produce seed, because the selection planted was highly susceptible to infection by Alternaria arborescens.