Estimating the Evolutionary Change in Growth Trajectories in the Perennial Plant Lythrum salicaria

University Of New Orleans, New Orleans LA

Investigators

Abstract

This project will use a unique approach to investigate genetic variation for life-history traits, such as size, in the long-lived invasive plant species, Lythrum salicaria (purple loosestrife). Instead of analyzing individual size-related life history in each season as has been done by other researchers, this project will consider the change in each trait through time. Six years of census data from an experimental garden established in 1993 has demonstrated that there is genetic variation for the pattern growth in this species. The proposed research will use additional census data from the established experimental garden and apply new statistical techniques from the field of quantitative genetics to investigate how selection acts on growth and genetic constraints on growth. Tradeoffs (negative correlations) between growth and reproduction will be investigated using both quantitative genetics and experiments manipulating reproductive effort. A new experimental garden of three cohorts of plants of different ages will be established to to determine whether year to year variation in life-history traits is due to the intensity of selection varying with age. Lythrum salicaria is an invasive species that is a serious pest in this country yet we still know little about its life history. Basic information on life span, lifetime reproductive success, contribution of each reproductive episode to total reproduction, etc. will be extremely valuable to researchers studying the invasiveness of this species. Investigating genetic variation for growth in this species is relevant to the fields of both evolutionary ecology and conservation biology.