Jeff Firestone

UC Davis Department of Plant Sciences
Weed Science Program
University of California
Davis, California 95616

Phone: (530) 752-8284

Email:["mailto:

firestone@ucdavis.edu">

firestone@ucdavis.edu</A><br /]

< My main research uses Lolium multiflorum, both as a model and an interesting weed in its own right. L. multiflorum, or annual ryegrass, is a common weed of orchards, vineyards and wheat, and found on most roadsides in Yolo County. It is also a desirable hay, pasture and cover crop species, and the subject of our herbicide resistance studies. It is wind pollinated and self-incompatible. I first located natural, small populations to determine if appear to suffer from decreased reproduction (i.e. Allee effects). The seeds collected from some of these populations are then the basis for a greenhouse / field experiment. A series of artificial, 'new invasions' are created, effectively isolated from each other while in similar conditions. In these created populations, I control the population size and putative genetic diversity independently. In natural, small populations, it is difficult or impossible to separate out the effect of having few individuals from having few alleles because there are so few individuals to carry them. This design should suggest the relative importance, in this system, of population size, genetic diversity (e.g. inbreeding), self-incompatibility and unexpected rabbit herbivory on the success of a small population of a plant species known to naturally increase.