Chromosome numbers of new Ulmus (elm) taxa introduced from China

4 Pages·1997·1.6 MB·English

by  F S Santamour

RHODORA,
No. 148-151, 1997
Vol. 99, 898,
pp.
NEW
CHROMOSOME NUMBERS OF ULMUS
(ELM)
TAXA INTRODUCED FROM CHINA
Frank S antamour,
S. Jr.
U.S. National Arboretum, Agricultural Research Service,
New
U.S. Department of Agriculture, 3501 York Ave., NE,
DC
Washington, 20002
Ware
George
H.
Morton Arboretum, IL 60532
Lisle,
= =
abstract. Diploid chromosome counts (2x In 28) are reported for
the first time in 12 elm taxa newly introduced into the United States from
China. These are Ulmus bergmanniana, U. bergmanniana var. lasiophylla,
U. castaneifolia, U. changii, U. chenmoui, U. elongata, U. gaussenii, U.
glaucescens, U. lamellosa, U. lanceaefolia, U. szechuanica, and U. taihang-
shanensis.
Key
Words: cytotaxonomy
cytology,
The most recent account of chromosome numbers Ulmus
in
=
=
(Santamour showed 24 were 2n
1993) that taxa diploid (2x
28) and that only U. americana L. (American elm) was a tetra-
= =
may
The
ploid (4x 2n 56). tetraploid nature of U. americana
be
a barrier to interspecific hybridization with diploid species but
Santamour (1970) reported on a natural triploid hybrid between
A
americana and pumila and
U. U. L. natural triploid involving
resembling americana was name
U. given the cultivar 'Jefferson'
by
Sherald and
(1994) another
et similar natural triploid
al.
"Washington") was
(called reported by Santamour and Bentz
Although Santamour was
(1995). (1972) unsuccessful crossing
in
the diploid, fall-flowering Chinese elm with
parvifolia Jacq.)
(£/.
americana, Smalley
U. (1993) reported of nu-
et the creation
al.
merous hybrids between these two taxa, but no chromosome
on may
counts these progenies have been made. Thus, while
it
not be impossible to utilize diploid taxa in hybridization programs
with American some may
the tetraploid elm, be en-
difficulties
may
countered and these be related chromosome numbers.
to
number "new"
of elm
and
the
ji
program
148
—
Santamour and Ware Ulmus Chromosome Numbers 149
1997]
listed 24 species and four varieties of Ulmus growing in China,
Of
which 24 were
of taxa native to that country. these taxa, dip-
chromosome
loid counts have been reported for U. davidiana
Planch., U. glaucescens lasiocarpa Rehd., U. laciniata
var.
pum-
Mayr, macrocarpa Hance, and
(Trautv.) U. U. parvifolia U.
Fu
(1980) did not recognize U. japonica (Rehd.) Sarg. or U.
ila.
synonymy
wilsoniana Schneid., but placed both in the of U. dav-
propinqua
idiana japonica (Rehd.) Nakai, along with U.
var.
com-
Koidz. Thus, likely that any taxon in the U. davidiana
is
it
number
plex would be remained a rather large
diploid. there
Still,
unknown
United
of Chinese were the States.
taxa that virtually in
Some of these taxa may have that could be important in
traits
been
breeding programs and Ulmus szechuanica has already
shown be feeding by the elm leaf beetle
to highly resistant to
(Miller and Ware 1994). Resistance of several other taxa to in-
sects and diseases suspected but many accessions have not been
is
young. Likewise,
widely tested because they are relatively
still
and
most introductions have not yet reached sexual maturity thus
hybrid-
have not been available for experiments in interspecific
ization.
would be desirable to
Preliminary such experimentation,
to it
new
know any of these
chromosome numbers of these taxa. If
the
more
might be
Chinese proved be tetraploid, they
introductions to
we made
have chro-
American Therefore,
crossable with elm.
mosome none of which, to our knowl-
on
counts of these taxa,
all
edge, have been reported previously.
Fu
Ulmus taihangshanensis are listed in
All of the taxa except
Ulmus
40 species of
Fu recognized
(1980). In 1980 paper, ca.
his
The
genus.
and new for the
classification
outlined a infrageneric
of the species,
was only for eight
subgeneric category indicated
was
placed
elongata in
however. For The Chinese U.
instance,
American but
species,
Mexicanae Fu with two North
series G.
L.
Ulmus
lanceaefolia
Fu
species.
failed to identify those additional
4*1
9 1 1 t-A. axon
Lanceaefoliae
bearing
made
(Santamour
150 Rhodora
99
[Vol.
MATERIALS AND METHODS
erminated
Morton Arboretum
Arboretum and chromosome numbers
determined
mitotic
at
me
unambiguous
three cour
each Herbarium
f taxon.
and
fruiting characteri
g,
he Morton Arboretum
ai
na
and mor.
ited
at
RESULTS
= =
Diploid (2x 2n 28) chromosome counts were made
for
each
of the following
taxa, listed in alphabetical order, with avail-
are
Morton
Arboretum: Ulmus bergmanniana
Schneid.
(R
castaneifolia
no
94-11) source data; U. changii Cheng (R 94-23) no source
chenmoui Cheng
data; U. (R 93-117) Anhui
Province; U. elon-
&
Fu
gata G. Ding
L. C. S. (R 94-6) Zhejiang Province;
U.
Cheng
gaussenii (R Anhui
94-8)
Province; glaucescens
U.
Wang
Shanxi
Province; U. lamellosa C.
lanceaefolia
Wall
source Wang
data; U. taihangshanensis
S. Y.
i)
DISCUSSION
These new
12 chromosome
diploid
counts
indicate that the
American elm may
tetraploid be
truly unique the genus Ulmus.
in
As we
know,
far as there are probably only Chinese
five or six
taxa that have not been studied Although
cytologically. un-
is
it
any of would
likely that these taxa be and perhaps be
tetraploid,
more crossable with American we
elm, endeavor
will obtain
to
seed of these taxa in the near future
—
Santamour and Ware Ulmus Chromosome Numbers
1997] 151
LITERATURE
CITED
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in China). Jour. North-Eastern Forestry 1-40. Chinese, En-
Inst. 3: (In
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G. and
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luteola Coleoptera: Chrysomelidae). Environm. 231-235.
Hort. 12:
J.
A
Santamour,
F. S., Jr. 1970. natural hybrid between American and Siberian
elms. Forest 149-153.
Sci. 16:
1972. Interspecific hybridization with and spring-flowering
fall-
•.
—elms. Forest 283-289.
Sci. 18:
1993. Cytological and biochemical aspects of elm improvement,
pp.
.
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New
Research: Cellular and Molecular Approaches. Springer- Verlag,
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—
and S. E. Bentz. 1995. Updated checklist of elm {Ulmus) cultivars
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J.
Sherald, Santamour, R. K. Hajela, N. Hajela, and M. B.
L., S. Jr.,
J. F.
A
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Forest Res. 24:
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E. B., R. Guries, D. T. Lester. 1993. Liberty
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New
Cellular and Molecular Approaches. Springer- Verlag, York.
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R. 1955. Alcoholic hydrochloric acid-carmine as a stain for chro-
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in