PARENT SESSION
Poster Session #4: Invasions.
Monday, August 6, 2001. Presentation from 10:30 AM to 12:00 PM. Exhibition Hall

The genetic variation of an invasive perennial, Lepidium latifolium L.(Cruciferae), across the western United States.

Printz, Lisa¹, Hoelzer, Guy², Taylor, George³, ^{1 2 3}

ABSTRACT- I surveyed variation in randomly amplified polymorphic DNA (RAPD) profiles to estimate the genetic diversity of Lepidium latifolium L., an aggressive, clonal, invasive plant introduced from Eurasia in the early 1900's. Samples from the Truckee River in Nevada, the Susan River in California, and 10 sites across the western United States were collected and analyzed. Significant mean within site genetic diversity for the Susan River (H_W=0.3984+0.14), Truckee River (H_W=0.4163+0.12), both rivers combined (H_W=0.4082+0.06), and across the west (H_W=0.3603+0.09), was detected. Sufficient genetic variation was detected within sites (Susan River, H_B=0.0326+0.03; Truckee River, H_B=0.0307+0.02) to reveal population subdivision if it existed at this scale (F_ST =0.1053+0.06 and 0.0695+0.04). However, there is population subdivision between the two river systems (F_ST =0.1216+0.06) and among the 10 western sites (F_ST = 0.2267+0.08). The genetic variation of L. latifolium in the western United States is high, both within and between populations, indicating sexual reproduction and gene flow among riverine sites and the accumulation of site specific loci at larger geographical scales, once gene flow is limited.

KEY WORDS: invasive, lepidium, mustard, genetics