Date: Mon, 11 Aug 1997 15:00:12 +0100 From: steiger@iae.unibe.ch (Juerg Steiger) To: cp@opus.hpl.hp.com Message-Id: <aabcdefg3046$foo@default> Subject: Re: temp Ping identification
>Gilles
I have two e-mail addresses of you - which is the better one?
>If a P. vulgaris has undergone an "introgression" by another species, can
>it still be considered as P. vulgaris ?
If a hybridogene species is completely stable, i.e. if it is
morphologically distinct and if its F1, F2 etc. generations do not split
up into the parent species it may be considered as an autonomus species
(usually stable hybrids are polyploid). Most modern cereals are such
hybridogenic species, originating from 2-3 parent species. A CP example is
D. anglica (2n=40), beeing a polyploid hybrid of D. linearis (2n=20) and D.
rotundifolia (2n=20). The diploid hybrid (2n=20) is sterile, while the
tetraploid (D. anglica) behaves as a fertile, autonomous species.
Introgression is not necesserily based on a 1:1 relation of the parent
species. One parent species may be chromosomically prevailing. Also the
cytoplasmatic heredity factors may contribute their part.
P. vulgaris has a rather large horizontal and vertical distribution area
and varies considerably from site to site. 'Your' P. vulgaris from the
Savoyan Alps is certainly within the usual intraspecific variation range of
this species.
Kind regards Juerg
________________________________________________
Dr. Juerg Steiger, Institut fuer Aus-, Weiter- und Fortbildung IAWF
University of Bern, Inselspital 37a, CH-3010 Bern, Switzerland
Office: +41 (0)31 632 9887 Fax: +41 (0)31 632 9871
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