Articles
GERMPLASM DEVELOPMENT AND PRELIMINARY INTERSPECIFIC HYBRIDIZATION IN PHLOX
Article number
953_9
Pages
71 – 78
Language
English
Abstract
The genus Phlox consists of approximately 65 species native mainly to continental USA and some parts of Mexico and Canada.
An important genus in the greenhouse and nursery industry, Phlox has a long history of cultivation in gardens because of showy flowers and variable habit.
Although numerous cultivars are available in the trade, the potential for improvement of existing forms as well as for novel traits and habits is enormous.
Because of its economic importance and potential for improvement, Phlox has been designated as a priority genus for the Ornamental Plant Germplasm Center in Columbus, Ohio, USA. A germplasm collection has been developed that now consists of more than 200 accessions and that is continuing to expand; this collection includes wild species as well as cultivated forms and is being characterized and evaluated for various traits, but of particular interest is the potential for genetic exchange between the various species of Phlox. Studies in the 1960s that focused on ecological adaptation and speciation in the genus suggest that barriers to interspecific exchange of genes may be weak, but the boundaries have not been delineated.
We have been examining the potential for improvement of horticultural traits by interspecific hybridization and have been attempting a series of crosses mainly between the 20 or so species native to the eastern USA. Over 5000 pollinations comprising more than 300 parental combinations have been completed thus far.
We have noted that crosses between long- and short-styled taxa fail to produce seeds; that crosses between species within subsections produce equivalent numbers of capsules and seeds as pollinations within species; and that some crosses are only possible in one direction.
In crosses between Phlox paniculata and P. carolina, only the former can function as the female parent.
Attempts at recreating the putative naturally occurring hybrids Phlox ×rugelii and Phlox ×glutinosa suggest that these may indeed be true hybrids as we have been able to produce seeds on both parental taxa.
Additional results of analysis with microsatellite markers as well as DNA content will be presented.
An important genus in the greenhouse and nursery industry, Phlox has a long history of cultivation in gardens because of showy flowers and variable habit.
Although numerous cultivars are available in the trade, the potential for improvement of existing forms as well as for novel traits and habits is enormous.
Because of its economic importance and potential for improvement, Phlox has been designated as a priority genus for the Ornamental Plant Germplasm Center in Columbus, Ohio, USA. A germplasm collection has been developed that now consists of more than 200 accessions and that is continuing to expand; this collection includes wild species as well as cultivated forms and is being characterized and evaluated for various traits, but of particular interest is the potential for genetic exchange between the various species of Phlox. Studies in the 1960s that focused on ecological adaptation and speciation in the genus suggest that barriers to interspecific exchange of genes may be weak, but the boundaries have not been delineated.
We have been examining the potential for improvement of horticultural traits by interspecific hybridization and have been attempting a series of crosses mainly between the 20 or so species native to the eastern USA. Over 5000 pollinations comprising more than 300 parental combinations have been completed thus far.
We have noted that crosses between long- and short-styled taxa fail to produce seeds; that crosses between species within subsections produce equivalent numbers of capsules and seeds as pollinations within species; and that some crosses are only possible in one direction.
In crosses between Phlox paniculata and P. carolina, only the former can function as the female parent.
Attempts at recreating the putative naturally occurring hybrids Phlox ×rugelii and Phlox ×glutinosa suggest that these may indeed be true hybrids as we have been able to produce seeds on both parental taxa.
Additional results of analysis with microsatellite markers as well as DNA content will be presented.
Publication
Authors
P. Zale , P. Jourdan
Keywords
germplasm, interspecific hybridization, Phlox, ornamental plants
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