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Wheat Information Service
Number 93: 27-31 (2001)
Research article
Third dominant male sterility gene in common
wheat
S. S. Maan and S. F. Kianian
Department of Plant Sciences, North Dakota State University,
Fargo, ND, U. S.A.
Summary
The mutants producing dominantly inherited male sterility
(Ms) survive in the polyploid species. Hexaploid wheat
(Triticum aestivum L.) has two Ms genes, Ms2 on
chromosome 4D and Ms3 on chromosome 5A. Our objective was to
determine the identity of a putative third Ms gene. First, we
crossed an euploid Msms plant to double-ditelosomic 5A (dDt;
2n=44; 20"+2t") of Chinese Spring (CS), a monoditelosomic 5A (mDt)
Msms F1 (2n=43; 20"+t1t''' 5A) to nullisomic
5A-tetrasomic 5D [(5A) 5D; 2n=42; 19"+1IV] of CS,
a 43-chromosome Msms plant (19"+1''' 5D+2t'5A) to CS, and
produced a 1: 1 ratio of fertile and sterile plants, showing that
Ms was not located on chromosome 5A. Second, we crossed an
euploid Msms plant to (4D)4A of CS, a tri 4A- mono 4D Msms
(2n=43; 19"+ l'''+ 1') plant to dDt 4D of CS, and produced
Msms plants (20 "+t1t'''4D) or dMt (20"+2t'4D) and fertile Dt
plants (20"+ 2t' ) or Mt (20"+t'), showing that Ms is located
on chromosome 4D. Third, a Msms dMt 4DL (20"+1t") plant was
crossed to CS and produced 21 sterile plants with 21", 21 fertile
plants with 20"+1t"4DL but no recombinants (msms with
21" or Msms with 20"+1t"), showing that Ms is
located in the short-arm of chromosome 4D (4DS). Fourth, two Msms
mDt 4D (20"+t1t''' ) plants (one with Ms in whole
chromosome 4D and the other with Ms in telo 4DS) were crossed
to CS and produced 1:1 ratios of fertile and sterile plants with 21"
as well as 20"+t1t", indicating that the new Ms (Ms4 )
gene is located in the distal portion of 4DS, while 4DS also has
Ms2 with 31.16 crossover units from the centromere.
Key words: Triticum, polyploidy, male sterility,
mutation, diploidized genes
Introduction
Common wheat has several male sterile mutants, but only three
have been located to specific chromosomes. One X-ray induced
ms1 recessive mutant is a null locus in the short arm of
chromosome 4A (previously chromosome 4B) (Sears 1954; Driscoll 1977).
Franckowiak et al. (1976) and Sasakuma et al. (1978) reported one
dominant (Ms3) and several recessive male sterile (ms)
mutants that were produced by EMS treatment of seed in the common
wheat cultivar, Chris, which has cytoplasm from Aegilops squarrosa
.L. The recessive msms gene pair produced male sterility
in the euplasmic as well as alloplasmic lines of common wheat.
Sasakuma et al. (1978) examined allelic 'relationships among the
Ms and ms mutants. Klindworth and coworkers (pers comm)
determined that two of those EMS-induced ms mutants studied by
Sasakuma et al. (1978) were allelic to ms1 located on
chromosome 4A.
The Ms3 mutant producing dominantly inherited male sterility
is closely linked to the centromere in the short-arm of chromosome 5A
of alloplasmic common wheat (Maan et al. 1987). Maan and Williams
(1984) transferred Ms3 to euplasmic common wheat by using
limited functional pollen in the male-sterile plants grown under
higher than normal greenhouse temperature conditions. The Ms3
gene is equally effective in producing dominantly inherited male
sterility in the euplasmic and alloplasmic common wheat cultivars and
can be maintained by backcrossing with common wheat or sib-mating
sterile and fertile segregants.
Genesis of the Ms2 gene is not known for certain. The
Ms2 gene is 31.16 crossover units from the centromere in the
short arm of chromosome 4D (4DS) and is presumably carried in the
euplasmic common wheat (Liu and Deng 1986a, b; Deng and Huang
1988).
The objective of this study was to determine the identity of a
putative third dominant Ms gene and to distinguish it from
those that are known to be located on chromosomes 5A, 4A and 4D of
common wheat.
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