A Database for Triticeae and Avena
V. 1. Linkage maps of barley, 1980*
T. Tsuchiya. Department of Agronomy, Colorado State University, Fort
Collins, Colorado 80523, U.S.A.
* Supported partly by Research Grant No. 12-14-5001-265 from USDA/SEA.
Results from the linkage analysis, conventional and translocation analysis,
have been published in recent volumes of Barley Genetics Newsletters and
some scientific journals. However, it has been rather difficult for this
author to locate many of those genes in the chromosome maps. Main causes
of the difficulties are:
1. Limited amount of information is based on the three point test, especially
with the back cross method with multiple recessive. Therefore, the information
may not be very reliable.
2. Some experiments have been carried out in the field where some homozygous
mutants could not survive. The data from this work may also not be very
3. Genetic markers which were well studied and rather precisely located
have not been included in the linkage analysis. Therefore, it is extremely
difficult to locate those genes adequately in the chromosome maps.
4. At present five of seven chromosomes have centromere located in the
chromosome map in relation to several marker genes based on the results
from telotrisomic analysis. Some 50 genes have been associated in 10 arms
of five chromosomes, 1 to 5. Under these circumstances, it is almost impossible
to locate some new mutant genes adequately in the chromosome map, because
it is extremely difficult to figure out with which arm these genes are
associated. Without arm location it is almost impossible to locate genes
in the chromosome maps of those five chromosomes.
The following are several aspects recognized in each chromosome:
Chromosome 1: There is a conflicting result on the arm location of ac2
in this chromosome (Søgaard, 1977b; Tsuchiya, 1972). The order of
three closely linked genes, br, gs3 and fc was established
as br-5.386-f 2.107-gs3 by three point test (Shahla,
1980). However, the telotrisomic analysis could not give a definite relationship
between centromere and these genes, (Shahla, 1980). The symbol (Rs)
for red stem should be changed. However, this will be maintained until
the whole system will be changed in the near future.
Chromosome 2: The symbol (Re 2) for the second gene for Purple
lemma and pericarp is also maintained as is the case of Rs. The
gene yst3 for yellow streak 3 was found not to be located either
2L or 2S (Tsuchiya and Hang, 1979), and eliminated from the map (Table
Chromosome 3: The symbol rnt for reduced number of tiller was
changed to lnt for lower number of tillers which was originally
suggested by the researcher (Nonaka, personal communication).
Chromosome 4: The gene i for deficiens has failed to show trisomic
ratio in the telotrisomic analysis with Triplo 4S (Tsuchiya and Hang, 1979).
However, it will remain at the same locus until more information is obtained.
Chromosome 5: A detailed map was presented by Jensen (1980). However,
there is some uncertainty for several genes in relation to the established
good markers. Thus the map has a rather limited number of genes located.
Other genes are listed in Table 1.
Chromosome 6: A necrotic leaf spot gene (nec) was reported to
be located on chromosome 6 (Kasha, 1980). Häuser and Fischbeck (1979)
also reported another necrotic gene on chromosome 6. However, these authors
did not show any results of allelism testing with necrotic genes on chromosome
6 reported by Jensen (1971). Therefore, it is difficult to even give a
symbol. I suggest J. Jensen, K. Kasha and G. Fischbeck communicate with
each other and solve the problem of this confusion. Based on the report
by Kasha (1980), alb,,q was eliminated from the map and placed in
Table 1. Centromere location in the linkage map is still not known.
Chromosome 7: No information on the definite centromere location is
available yet. Many genes associated with this chromosome have not been
located in the map without question.
Because of those problems discussed above the linkage maps have not
been improved very much this year. More information is needed from the
detailed linkage analysis with the use of multiple genetic marker stocks
including well known gene markers for further improvement of linkage maps
Figure 1 shows linkage maps with some revisions. Table 1 presents the
list of genes associated with each chromosome or chromosome arm.
Figure 1. Linkage maps of barley, 1980.
Table 1. List of genes associated but not located
definitely with respective chromosome/chromosome arm in barley, 1980.
1. Jensen, J. 1971. Mapping of 10 mutant genes for necrotic spotting
in barley by means of translocation. Barley Genetics II (Proceed. IInd
Intern. Barley Genet. Symp.):213-219.
2. Jensen, J. 1980. Coordinator's report: Chromosome 5. BGN 10:88-90.
3. Kasha, K.J. 1980. Coordinator's report: Chromosome 6. BGN 10:
4. Seip. L. and T. Tsuchiya. 1979. Trisomic analysis of a mutant gene
ovl for ovaryless or male in barley. BGN 9:89-90.
5. Shahla, A. 1980. Physical localization of genes in the short arm
of chromosome 1 (1S) in barley. Ph.D. Thesis. Colorado State Univ., Fort
Collins, Colorado, U.S.A. 91pp.
6. Søgaard, B. 1977a. The localization of eceriferum loci in
barley. IV. Three point tests of genes on chromosome 7 in barley. Carlsberg
Res. Commun. 42:35-43.
7. Søgaard, B. 1977b. Ibid. V. Three point tests of genes on
chromosome 1 and 3 in barley. Carlsberg Res. Commun. 42:67-75.
8. Tsuchiya, T. 1972. Cytogenetics of telotrisomics in barley. BGN 2:93-98.
9. Tsuchiya, T. and A. Hang. 1979. Telotrisomic analysis of yst3 and
i in barley. BGN 9:106-108.
BGN 10 toc
BGN Main Index