CSIRO Publishing blank image blank image blank image blank imageBooksblank image blank image blank image blank imageJournalsblank image blank image blank image blank imageAbout Usblank image blank image blank image blank imageShopping Cartblank image blank image blank image You are here: Journals > Australian Journal of Botany   
Australian Journal of Botany
Journal Banner
  Southern Hemisphere Botanical Ecosystems
 
blank image Search
 
blank image blank image
blank image
 
  Advanced Search
   

Journal Home
About the Journal
Editorial Board
Contacts
Content
Current Issue
Just Accepted
All Issues
Special Issues
Turner Review Series
Sample Issue
For Authors
General Information
Notice to Authors
Submit Article
Open Access
For Referees
Referee Guidelines
Review an Article
Annual Referee Index
For Subscribers
Subscription Prices
Customer Service
Print Publication Dates

blue arrow e-Alerts
blank image
Subscribe to our Email Alert or RSS feeds for the latest journal papers.

red arrow Connect with us
blank image
facebook twitter youtube

red arrow PrometheusWiki
blank image
PrometheusWiki
Protocols in ecological and environmental plant physiology

 

Article << Previous     |     Next >>   Contents Vol 39(6)

Polyploidy and Ribosomal-DNA Spacer Variability in Poa labillardieri

CE May and MH Campbell

Australian Journal of Botany 39(6) 567 - 574
Published: 1991

Abstract

With changing agricultural practices, poa tussock (Poa labillardieri Steud.) has become a serious weed of Australian tableland pastures. To determine whether there are any genetic differences within the species that might have a bearing on this problem, accessions of P. labillardieri from seven localities in south-eastern Australia were grown in a field nursery at Bathurst for comparison of their morphological attributes. Seeds from plants grown in this nursery were collected, and a further generation of plants was grown in a glasshouse for cytogenetic and molecular genetic studies. In adult plants of this generation, there were three karyotypic groups with chromosome numbers varying from 2n = 4x = 28, in nonglaucous tussocks of the Upper Hunter Valley, to 2n = 8x = 56, in glaucous tussocks from the Central and Southern Tablelands, to 2n = 12x = 84, in a Victorian coastal tussock. Because the number of chromosomes present in some seedlings from Cooma parents varied from 35 to 49 to 56, diploid or hexaploid plants must also have been present in the Bathurst nursery and contributed to the odd-ploidy seedling chromosome numbers.

Ribosomal spacer DNA fragments were investigated using the wheat probe pTa250.4 to label homologous DNA sequences in genomic DNA extracted from the leaves of individual plants of P. labillardieri. Although specific DNA fragments could not be linked to either localities or levels of ploidy, they did show evidence of cross-pollination between plants of the different accessions. These levels of cytogenetic and DNA sequence variability, and the evidence they provide of widespread outcrossing within plants of similar ploidy and of hybridisation between plants of differing ploidy, may well help to explain the success of this species as a weed and affect the control measures used to stop its spread.



Full text doi:10.1071/BT9910567

© CSIRO 1991

blank image
Subscriber Login
Username:
Password:  

 
PDF (488 KB) $25
 Export Citation
 Print
  
    
Legal & Privacy | Contact Us | Help

CSIRO

© CSIRO 1996-2014