Assessing the effect of inbreeding and long-distance gene flow on the invasive potential of Senecio pterophorus (Asteraceae)

• Published in: Australian journal of botany Vol. 56; no. 6; pp. 539 - 549
• Main Authors: Caño, Lidia, Escarré, Josep, Blanco-Moreno, José M, Sans, F. Xavier
• Format: Journal Article
• Language: English
• Published: Collingwood, Victoria: CSIRO Publishing 01.01.2008
• Subjects: flowering; gene flow; genetic bottlenecks; genetic variation; genotype; heterosis; inbreeding; inbreeding depression; introduced plants; invasive species; phenology; plant fertility; population genetics; seed germination; seed set; selfing; Senecio; Senecio pterophorus; vigor; South Africa; Spain
• ISSN: 0067-1924; 1444-9862
• DOI: 10.1071/BT07100

Alien invasive species undergo genetic bottlenecks during the colonisation of new areas that can lead to a loss of genetic variation within populations and to subsequent reproductive constraints. We analysed the self-compatibility and the effects of inbreeding and inter-population gene flow in the fitness of one native and one introduced population of the invasive Senecio pterophorus D.C. Plants were self-pollinated and outcrossed within families, within populations, between local populations and between populations located in the native and introduced range. Self-pollinated individuals from both populations produced almost no seeds, thus revealing self-incompatibility. High family-level variation was observed in the effect of pollination treatment on seed set and total fitness. Overall, in the Spanish population, related crosses produced fewer seeds and lower germination rates than unrelated crosses. In the South African population, inbreeding depression affected the probability of flowering. Heterosis was found to affect seed set in both populations and growth and mean pre-reproductive time in the Spanish population. We discuss the effects of the incompatibility system, inbreeding depression and long-distance gene flow within the introduced population with respect to the invasive potential of S. pterophorus in north-eastern Spain.