Hexaploid seeds are produced by predominantly tetraploid populations of Hypericum perforatum, but the fate of hexaploid seedlings and their reproductive behavior have not been closely examined. We used flow cytometry to analyze single seeds and individual plant samples of three accessions of H. perforatum to determine ploidy levels and reproductive pathways. Seed samples of all three accessions...

Senecio carniolicus (Asteraceae) is an intricate polyploid complex distributed in the European Alps (di-, tetra- and hexaploids) and Carpathians (hexaploids only). Molecular genetic, ecological, and crossing data allowed four evolutionary groups within S. carniolicus to be identified. Here, we establish that these four groups (two vicariant diploid lineages, tetraploids and hexaploids) are also...

Allopolyploidization in plants is an important event that enhances heterosis and environmental adaptation. Common wheat, Triticum aestivum (AABBDD), which is an allohexaploid that evolved from an allopolyploidization event between T. turgidum (AABB) and Aegilops tauschii (DD), shows more growth vigor and wider adaptation than tetraploid wheats. To better understand the molecular basis for the h...

Evolutionary trajectory and occurrence history of polyploidy have been extensively studied in plants, but they remain quite elusive in vertebrates. Here, we sampled and gathered 4,159 specimens of polyploid Carassius species complex including 1,336 tetraploids and 2,823 hexaploids from a large geographic scale (49 localities) across East Asia, and identified a huge number of 427 diverse haploty...

—Andropogon gerardii populations are comprised of two (or more) polyploid forms over much of the range of the species. To understand the impact of intraspecific polyploidy, polyploid cytotypes were compared over 4 y in native grasslands in Boulder, Colorado. Boulder A. gerardii populations averaged 59.6% hexaploids (60 chromosomes), 35.3% enneaploids (90 chromosomes) and 5.1% intermediate (aneu...

Chromosome numbers are reported here for the first time from 117 individuals of Solidago rugosa and S. fistulosa. Including 178 previously published reports two species plus latissimifolia, chromosome have been determined 295 269 locations. Only diploids (2n = 18) were found throughout range fistulosa on coastal plain in eastern U.S.A. (44 counts). Diploids northern portion tetraploids 36) hexa...

Abstract Polyploids with odd-ploidy levels may play an important evolutionary role as they enable backcrosses their parental cytotypes. We chose the ploidy-variable Senecio carniolicus species group to address overarching question if pentaploid individuals, which occur at high frequencies in immediate contact zones of tetraploids and hexaploids, mediate effective interploidy gene flow. employed...

N an earlier paper (GEIRINGER 1948) the author has investigated the matheI matical genetics of autopolyploids if one locus is considered and chromosome segregation is assumed. A paper on the linkage theory of autopolyploids (m loci), under the same assumption, is in press (GEIRINGER 1949). However, while chromosome segregation might be assumed as an approximation theory, the study of polyploids...

Interspecific hybridization is recognized as a potentially destructive process that represents a major threat to biodiversity. The rate of population displacement by hybridization can be rapid, but underlying mechanisms are often obscure. One hypothesis is that a species may be driven to extinction by interspecific gene flow, or pollen swamping, when hybrids are inviable or sterile. Here, we do...