PARENT SESSION
Poster Session #58: Invasive Species Control.
Thursday, August 8. Presentation from 8:00 AM to 9:30 AM. Exhibit Hall B & C, TCC

Apomixis and plant invasion: Avoiding the pitfalls of selfing and outcrossing.

Scofield, Douglas^*,1,2, ¹ University of Miami, Coral Gables, FL² d.scofield@umiami.edu

ABSTRACT- Because apomixis, like selfing, allows uniparental production of seed, it has long been considered to be a trait that may contribute to invasiveness in plants. However, asexual apomixis offers invading plants significant advantages over selfing that have not been widely appreciated. Apomictic invaders may avoid the perils of small populations that selfing and outcrossing invaders are likely to experience, including inbreeding depression and loss of heterozygosity. Furthermore, evolutionary disadvantages of asexual reproduction - the inability to produce new adaptive genotypes and the accumulation of deleterious mutations - may have little effect during the relatively short timescales which apomictic invaders may require to inflict great damage on alien ecosystems, particularly if parental genotypes have already experienced selection in the alien environment. In fact, selection can favor apomixis following invasion. If invaders have mixed apomixis-outcrossing breeding systems, as do a number of woody invaders, these disadvantages may not apply at all. Although many herbaceous invaders, such as Taraxacum, are widely recognized to be apomictic, a large number of woody invaders are apomictic as well, including some of the most invasive taxa in the families Melastomataceae and Rosaceae. Because of the recent explosion of research seeking to foster the "asexual revolution" - the genetic engineering of apomixis into crop plants - these implications should be considered.

KEY WORDS: invasive plants, apomixis, asexual reproduction