Genetic and Cytological Investigations in Sexual Erigeron compositus (Asteraceae)

Publisher Website
Google Scholar
Abstract
Erigeron compositus is an agamospermous species complex comprising sexual and agamospermous elements. Five subspecies were informally proposed by Beaman for sexual E. compositus: "anticus," "compositus," "pectinipetiolatus," "penicillatus," and "posticus." Chromosome counts reported herein show that sexual E. compositus is predominantly diploid, 2n = 18. Sexual tetraploids, 2n = 36, and an aneuploid, 2n = 35, were also observed. Genetic variation was examined in all of the proposed subspecies, with the exception of E. compositus "anticus," and in closely related E. vagus. The four proposed subspecies investigated are allozymically very similar with a mean genetic identity value (I) of 0.847. Likewise, comparisons between populations of E. vagus and E. compositus yield an I value of 0.889. Fixation indices derived from allozyme data also show that sexual E. compositus and E. vagus are strongly outcrossing. Allozyme markers, genetic similarity values, and patterns of morphological variation suggest that sexual tetraploid E. compositus is derived from a cross between diploid E. compositus "compositus" and one or more other sexual "subspecies" of E. compositus. These results represent the first phase in the chromosomal and genetic analysis of the E. compositus agamospermous complex.

This publication has 0 references indexed in Scilit: