Document Detail


Eco-geographically divergent diploids, Caucasian clover (Trifolium ambiguum) and western clover (T. occidentale), retain most requirements for hybridization.
MedLine Citation:
PMID:  21880661     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND AND AIMS: DNA sequence similarities and hybridization patterns in Trifolium (clovers) section Trifoliastrum suggest that rapid radiation from a common ancestral source led to this complex of diverse species distributed across Europe, western Asia and North Africa. Two of the most geographically and ecologically divergent of these species are the rhizomatous T. ambiguum from high altitudes in eastern Europe and western Asia and the stoloniferous T. occidentale from sea level in western Europe. Attempts were made to hybridize these species to ascertain whether, despite this separation, gene flow could be achieved, indicating the retention of the genetic factors necessary for hybridization.
METHODS: Three F(1) hybrids formed after embryo rescue were described, characterized by conventional and molecular cytogenetics, subjected to fertility tests and progeny generations were developed.
RESULTS AND CONCLUSIONS: Partially fertile hybrids between Trifolium ambiguum and T. occidentale were obtained for the first time. The F(1) hybrids produced seeds after open-pollination, and also produced triploid progeny in backcrosses to T. occidentale from the functioning of unreduced gametes in the hybrids. These plants were fertile and produced progeny with T. occidentale and with T. repens. Meiotic chromosome pairing in the F(1) showed six to eight bivalents per pollen mother cell, indicating pairing between the parental genomes. A chromosome-doubled form of one hybrid, produced using colchicine, showed some multivalents, indicative of interspecific chromosome pairing. The hybrid plants were robust and combined phenotypic characteristics of both species, having stolons, thick roots and a few rhizomes. Results show that despite separation by the entire breadth of Europe, the speciation process is incomplete, and these taxa have partially retained most of the genetic compatibilities needed for hybridization (possibly except for endosperm development, which was not tested). The fertile progeny populations could lead to new clover breeding strategies based on new hybrid forms.
Authors:
Warren M Williams; Isabelle M Verry; Helal A Ansari; S Wajid Hussain; Ihsan Ullah; Michelle L Williamson; Nicholas W Ellison
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2011-08-31
Journal Detail:
Title:  Annals of botany     Volume:  108     ISSN:  1095-8290     ISO Abbreviation:  Ann. Bot.     Publication Date:  2011 Nov 
Date Detail:
Created Date:  2011-10-21     Completed Date:  2012-03-22     Revised Date:  2013-05-23    
Medline Journal Info:
Nlm Unique ID:  0372347     Medline TA:  Ann Bot     Country:  England    
Other Details:
Languages:  eng     Pagination:  1269-77     Citation Subset:  IM    
Affiliation:
AgResearch Grasslands Research Centre, Private Bag 11008, Palmerston North 4442, New Zealand. warren.williams@agresearch.co.nz
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MeSH Terms
Descriptor/Qualifier:
Chimera / genetics*
Chromosome Pairing
Diploidy*
Europe
Gene Flow
Gene Transfer, Horizontal
Genetic Speciation
Genome, Plant
Hybridization, Genetic
Trifolium / genetics*
Triploidy
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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