Formation of a hybrid triploid agamosperm on a sexual diploid plant: Evidence from progeny tests in Taraxacum platycarpum Dahlst.

Chika Mitsuyuki, Akihiko Hoya, Hiroyuki Shibaike, Mikio Watanabe, Tetsukazu Yahara

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6 Citations (Scopus)

Abstract

Agamospermous dandelions of hybrid origin between a native sexual diploid species (Taraxacum platycarpum Dahlst. or T. japonicum Koidz.) and an alien agamospermous triploid [T. officinale Weber and T. laevigatum (Willd.) DC.] are now widely distributed throughout mainland Japan. These hybrid dandelions are known to be genetically variable. We hypothesized that this variability is maintained by repeated ongoing hybridization, based on the fact that triploid dandelions not only produce seeds agamospermously, but also produce some functional pollen grains that are able to sire seeds of sexual dandelions. To test this hypothesis, we examined whether heads of Japanese diploid dandelions produce new hybrid seeds after fertilization by pollen from triploid agamosperms under field conditions. One of the 430 tested plants grown from sexual dandelion seeds had morphological and molecular characteristics, which are consistent with a hybrid origin. The plant formed a hybrid surrounded by many individuals having recurved involucral bracts, in which frequency of T. officinale was very low (3.5 %). Cytological data and bagging experiments demonstrate triploidy and asexual seed production of the hybrid. Taken together, these results supported that the new hybrid is probably derived from a backcross of a hybrid to the native sexual species. Our findings provide evidence for the evolution of a new agamosperm through interspecific hybridization as a contemporary population process.

Original languageEnglish
Pages (from-to)863-870
Number of pages8
JournalPlant Systematics and Evolution
Volume300
Issue number5
DOIs
Publication statusPublished - May 2014

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All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics
  • Plant Science

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