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In view of the above, as
emphasized by us earlier (Gupta and Baum. 1986), we support the view
that Aegilops L. be recognized as a valid independent genus.
Therefore, the question remains whether the D genome diploid species
is Ae. tauschii Cosson or Ae. squarrosa L. Since Ae.
squarrosa L. is an illegitimate name for D genome diploid species
as pointed out by Yen et a]. (1997), Ae. tauschii Cosson
is the only correct name for D genome species, if Aegilops is
retained as an independent genus, and if D genome diploid species are
included in this genus. However, since in scientific literature and
also in text books, Ae. squarrosa is being used for a long
time as a popular name for the D genome diploid species, it will
again cause lot of confusion, if this popular name is replaced by the
botanically correct name Ae. tauschii Cosson. We, therefore, suggest
that for D genome diploid species, the name Ae. squarrosa with
a new type specimen be conserved and Ae. tauschii with its
type specimen be rejected. This should be possible under Article 14
of the code, which allows conservation against both homotypic as well
as against rejected heterotypic synonyms. Fortunately, in the Tokyo
code the scope of conservation of taxa at the species level has been
widened to allow conservation of even those species that are of no
economic value. Earlier, while conserving the name T. aestivum
for bread wheat, against T. hybernum, which had priority,
rules of nomenclature under ICBN were modified to allow for the
conservation of names of only the economically important species
(Karguelen 1980). The Tokyo code also provides for rejection of any
name (irrespective of rank), that would cause disadvantageous
nomenclatural change. Therefore, it should be possible to reject
Ae. tauschii Cosson, since its adoption as the valid name for
D genome diploid species will certainly cause disadvantageous
nomenclatural change. Actually. at the Tokyo congress, the
Nomenclature Section made it clear that 'Indulging in futile name
changes ( in the present case from Ae squarrosa to Ae.
tauschii) in the future is reprehensible unless the new
conservation/rejection avenues have previously been explored and
found to be unhelpful" (Nicolson and Greuter 1994).
While examining the question of nomenclature of the D genome diploid
species, we also need to address to the question of large scale
destabilization of generic names in the tribe Triticeae. We
recognized two main reasons for destabilization of names in the
Triticeae (Gupta and Baum 1989); the first is due to changing
taxonomy and the second is due to application of the rules laid down
'in ICBN. One would accept that continuous generation of information
and its desired input in taxonomy may require changes in
classification and therefore in the names of taxa.. Therefore, we
should strive for a stable classification that would require minimum
changes in the names of taxa. This is possible only when maximum
information from all disciplines is used for classification.
Unfortunately, this has not been done and cytogeneticists in the past
always suggested newer classifications with altered names of taxa.
The most conspicuous of these classifications are the genomic systems
of classification suggested by Love (1984) and Dewey (1984), who
suggested hat each taxon with a novel genomic constitution be
recognized as a separate genus. Consequently, Love (1984) defined 38
independent genera in the tribe Triticeae. In this classification,
Love (1984) grouped diploid wheats (A genome) into a separate
genus Crithodium Link, and tetraploid wheats (AB genomes) into
the new genus Gigachilon Seidl, thus leaving only hexaploid
wheats in the genus Triticum. The 38 genera of Triticeae
proposed in this genomic system of classification included 13 new
genera to accommodate the different species of the traditional genus
Aegilops L., which on the other extreme, was once merged
with Triticum. Under this new system, Ae. squarrosa L.,
the D genome diploid species, has been placed in a new genus
Patropyrum A. Love. However, we criticized earlier this
genomic system of classification (Baum et al. 1987), and fortunately
as a relief to the non-taxonomist users of these taxa, the new names
did not find any wide usage. It is, thus, obvious that major
destabilization in the common traditional names can sometimes be
caused by a new system of classification. It is, therefore, suggested
that changes in classification, if absolutely necessary, be proposed
on the basis of maximum information, and not on the basis of limited
information as done in genomic system of classification. Therefore,
any destabilization in the names due to changes in classification may
be difficult to control, but needs to be restricted by not using such
classifications.
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