The transition to gender dimorphism on an evolutionary background of self-incompatibility: An example from Lycium (Solanaceae)

Jill S. Miller, D. Lawrence Venable

Research output: Contribution to journalArticle

30 Scopus citations

Abstract

Populations of three North American species of Lycium (Solanaceae) are morphologically gynodioecious and consist of male-sterile (i.e., female) and hermaphroditic plants. Marked individuals were consistent in sexual expression across years and male sterility was present throughout much of the species' ranges. Controlled pollinations reveal that L. californicum, L. exsertum, and L. fremontii are functionally dioecious. Fruit production in females ranged from 36 to 63%, whereas hermaphrodites functioned essentially as males. Though hermaphrodites were mostly male, investigation of pollen tube growth reveals that hermaphrodites of all dimorphic species were self-compatible. Self-fertilization and consequent inbreeding depression are commonly invoked as important selective forces promoting the invasion of male-sterile mutants into cosexual populations. A corollary prediction of these models is that gender dimorphism evolves from self-compatible ancestors. However, fruit production, seed production, and pollen tube number following outcross pollination were significantly higher than following self-pollination for three diploid, cosexual species that are closely related to the dimorphic species. The data presented here on incompatibility systems are consistent with the hypothesis that polyploidy disrupted the self-incompatibility system in the gynodioecious species leading to the evolution of gender dimorphism.

Original languageEnglish (US)
Pages (from-to)1907-1915
Number of pages9
JournalAmerican journal of botany
Volume89
Issue number12
DOIs
StatePublished - Dec 1 2002

Keywords

  • Breeding systems
  • Dioecy
  • Gynodioecy
  • Lycium
  • Polyploidy
  • Self-compatibility
  • Self-incompatibility
  • Solanaceae

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Genetics
  • Plant Science

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