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Genome Designations in the Triticeae

Those attending the Second International Triticeae Consortium agreed to adopt a standard set of symbols for the individual haplomes of the Triticeae. A committee consisting of R.R.-C. Wang (Chair), R. von Bothmer, J. Dvorak, G. Fedak, I. Linde-Laursen, and M. Muramatsu met with two goals:

1) to develop a set of rules for designating haplome symbols for the Triticeae and

2) to develop a set of symbols that based on existing knowledge of the tribe.

The results of their deliberations were published in the Proceedings of the Symposium. The information presented here is based on that publication and subsequent discussions.

I have taken the liberty of proposing an additional rule. It is clearly identified as such in what follows. To my mind, preparation and citation of voucher specimens is essential if the designation of haplome symbols and publication of haplomic constitutions are to have the permanence and verifiability that is critical to scientific work.

Anyone wishing to propose changes or additions to the rules and symbols presented here should contact Dr. R.R.-C. Wang. For errors in the Web pages, contact Dr. Mary Barkworth.

Rules for Haplome Designation

  1. Haplome symbols should be written in bold face.

  2. Different basic haplomes in the Triticeae (with x = 7), defined as having less than 50% of complete meiotic pairing (i.e., c < 0.5) in a a diploid hybrid in the absence of the Ph or other pairing promoter/suppressor gene effect, should be designated with different symbols.

  3. Single upper case letters of the Roman alphabet (A-Z) should, as far as possible, be used as symbols for the basic haplomes.

  4. Additional basic haplomes should be designated by an upper case letter followed by a lower case letter.

  5. The haplome designation of a polyploid taxon should be given as a combination of the symbols of its constituent basic diploid haplomes.

  6. Unknown or unverified haplomes should be designated X followed by a lower case letter (e.g., Xu for Hordeum murinum). When a haplome has been sufficiently identified as distinct from all other established basic haplomes, it should be given its own haplome symbol.

  7. The letter Y has previously been used to designate unknown haplomes, but it has also been extensively used to designate on the haplomes present in species of Elymus sensu lato. It is now restricted to use in Elymus sensu lato.
  8. Modified versions of a basic haplome should be indicated by superscripts in lower case that are indicative of one of the species carrying such modified haplomes. Further modifications may be indicated by superscripted numerals.

  9. When a previously unrecognized basic haplome is identified, a symbol should be assigned to it in accordance with these rules.

  10. A haplome symbol may be underlined to indicate the origin of the cytoplasm of an alloploid species.

  11. From 1996 on, the haplome symbols designations presented here should have priority over subsequent proposals.

Proposed Addition to the Rules (no action has been taken on this proposal).

Any time the haplomic constitution of a taxon is determined, a herbarium specimen shall be prepared from a mature plant of the material used. This voucher specimen must be deposited in an internationally recognized herbarium. Publication of the haplomic constitution must include the code of this herbarium and sufficient additional information to enable the specimen concerned to be identified unequivocally.

Comment: Correct identification of the material used is essential if determinations of haplomic constitution are to be of value. Deposition of voucher material ensures that determinations can be verified at a later date and that, if the taxonomy of the group involved is changed, the haplomic information can be associated with the appropriate newly recognized or modified taxa.

A useful criterion for "internationally recognized herbarium" is listing in Index Herbariorum but the most critical aspect is that it should be a herbarium whose specimens are regularly consulted by taxonomists and one that is willing to loan specimens to other herbaria on request. Personal herbaria do not meet these criteria, nor do some research station herbaria.

Haplome Symbols

The table below is based on Wang et al. (1996), but I have a) changed the generic concepts adopted, b) listed the taxa alphabetically, c) eliminated the references to previous designations, and e) added a column for listing the accession code and number of herbarium specimens that document a particular report. The reason for adding the last column is given above.

I have also started a set of files for listing all taxa in the Triticeae in which the haplomic constitution of each taxon will be listed, if it has been determined directly rather than inferred from its morphology. This set of files will be built up slowly, as time permits.

Genera listed in the table: Aegilops, Agropyron, Australopyrum, Crithopsis, Dasypyrum, Elymus (includes Elytrigia), Eremopyrum, Festucopsis, Henrardia, Heteranthelium, Hordeleymus, Hordeum, Kengyilia, Leymus, Pascopyrum, Peridictyon, Psathyrostachys, Thinopyrum (includes Lophopyrum, Trichopyrum), Triticum. [This listing is repeated at the end of the table].

Taxon Haplomic Symbol or Constitution Reference Voucher Specimen
Aegilops bicornis Sb    
Aegilops biuncialis UM    
Aegilops caudata C    
Aegilops columnaris UM    
Aegilops comosa M    
Aegilops crassa (4x) DcXc Zhang et Dvorak 1992  
Aegilops crassa (6x) DDcXc Zhang et Dvorak 1992  
Aegilops cylindrica CD    
Aegilops juvenalis DcZcU McNeil et al. 1994  
Aegilops longissima Sl    
Aegilops mutica T Kimber et Tsunewaki 1988;  
Aegilops ovata UM    
Aegilops recta UMN, UMX Kimber et Tsunewaki 1988;; Yen et Kimber 1992  
Aegilops searsii Ss    
Aegilops sharonensis Sl    
Aegilops speltoides S. Proposal to change to B Jauhar et al. 1999. Journal of heredity 90:437-445.  
Aegilops tauschii D    
Aegilops triaristata UMN    
Aegilops triuncialis UC Kimber et Tsunewaki 1988;  
Aegilops umbellata U    
Aegilops uniaristata N    
Aegilops variabilis US USl Kimber et Tsunewaki 1988; Zhang et al. 1992  
Aegilops ventricosa DN Kimber et Tsunewaki 1988  
Agropyron P    
Australopyrum W    
Crithopsis K    
Dasypyrum villosum V    
Dasypyrum breviaristatum Vb Shoji Ohta & Miki Morishita (in press)  
Douglasdewey deweyi StP    
Douglasdeweya wangyii StP    
Elymus batalinii StPY Jensen 1990  
Elymus caucasicus StY Jensen et Wang 1991  
Elymus drobovii StHY Dewey 1980  
Elymus repens (Type species of Elytrigia) StStH Assadi et Runemark 1994; Vershinin et al. 1994  
Elymus scabrus StWY Torabinejad et Mueller 1993  
Elymus sibiricus (Type species of Elymus) StH    
Elymus transhyrcanus StStH Dewey 1972  
Eremopyrum FXe Sakamoto 1979; Frederiksen et Bothmer 1989  
Festucopsis L    
Henrardia O    
Heteranthelium Q    
Hordelymus XoXr Bothmer et al. 1994  
Hordeum bulbosum I    
Hordeum marinum Xa Bothmer et al. 1986  
Hordeum murinum Xu Bothmer et al. 1987, 1988a, 1998b  
Hordeum vulgare I    
Hordeum, other species H    
Kengyilia StPY Yen et Yang 1990  
Leymus NsXm Zhang et Dvorak 1991; Wang et Jensen 1994  
Pascopyrum smithii StHNsXm Zhang et Dvorak 1991  
Peridictyon sanctus Xp Seberg et al. 1991  
Psathyrostachys Ns    
Pseudoroegneria St    
Pseudoroegneria deweyi StP Jensen et al. 1992  
Pseudoroegneria geniculata subsp. scythica EeSt Liu et Wang 1992  
Pseudoroegneria pertenuis StP Wang et al. 1986; Assadi 1995
Secale R    
Taeniatherum Ta    
Thinopyrum bessarabicum Eb Wang 1985  
Thinopyrum caespitosum EeSt Liu et Wang 1989, 1993b  
Thinopyrum curvifolium Eb Eb Liu et Wang 1993a  
Thinopyrum distichum EbEe Liu et Wang 1993a  
Thinopyrum elongatum Ee Wang 1985  
Thinopyrum intermedium EeEeSt EbEeSt Liu et Wang 1993b Xu et Conner 1994  
Thinopyrum junceiforme EbE e Liu et Wang 1992  
Thinopyrum junceum EbEbEe Liu et Wang 1993a  
Thinopyrum nodosum EeSt Liu et Wang 1993b  
Thinopyrum sartorii EbE e Liu et Wang 1992  
Thinopyrum scirpeum EeEe Liu et Wang 1993a  
Triticum aestivum AuBD    
Triticum durum AuB Dvorak et al. 1993  
Triticum monococcum Am Dvorak et al. 1993  
Triticum recta UMN UMX Kimber et Tsunewaki 1988; Yen et Kimber 1992
Triticum syriacum DMS DcSsX Kimber et Tsunewaki 1988; Zhang et Dvorak 1992  
Triticum timopheevii AuG Dvorak et al. 1993  
Triticum zhukovskyi AmAuG Dvorak et al. 1993  
Triticum uartu Au Dvorak et al. 1993  

Genera listed in the table: Aegilops, Agropyron, Australopyrum, Crithopsis, Dasypyrum, Elymus (includes Elytrigia), Eremopyrum, Festucopsis, Henrardia, Heteranthelium, Hordeleymus, Hordeum, Kengyilia, Leymus, Pascopyrum, Peridictyon, Psathyrostachys, Thinopyrum (includes Lophopyrum, Trichopyrum), Triticum.