A Database for Triticeae and Avena
II. 17. Telotrisomic analysis of three genes with newly obtained
telotrisomic, Triplo 3S, in barley. (1)
R. J. Singh, A. Shahla and T. Tsuchiya, Department of Agronomy, Colorado
State University, Fort Collins, Colorado 80523, U.S.A.
(1) Supported by USDA/SEA Competitive Research Grant 5901-0410-9-0334-0
and USDA/SEA Cooperative Research Grant 12-14-5001-265 and CSU Hatch Project.
The first telocentric chromosome for chromosome 3 (Tsuchiya, 1971a)
was designated as telo 3A (Tsuchiya, 1971b). Telocentric chromosome 3A
was later identified as the long arm of chromosome 3 (telo 3L) based on
the morphological similarity of telotrisomic 3A (Triplo 3A) to its primary
trisomic (Triplo 3, Pale)(Tsuchiya and Singh, 1973). However, telotrisomic
analysis of many genes which were previously located in the short arm of
chromosome 3 (3S) by Robertson (1971) showed that these genes segregated
in the trisomic fashion (Singh and Tsuchiya, 1974; Tsuchiya and Singh,
1982). Based on these results, telo 3A was redesignated as telo 3S (Singh
and Tsuchiya, 1974, 1977, 1981c; Tsuchiya, 1974, 1980; Tsuchiya and Singh,
1982). However, recent results from Giemsa banding karyotype analysis (Singh
and Tsuchiya, 1982a) clearly showed that telocentric chromosome 3A was
actually the long arm (3L) (Singh and Tsuchiya, 1981b, 1982b).
Recently a new telocentric chromosome was obtained in chromosome 3 (Singh
and Tsuchiya, 1981a; Tsuchiya et al. 1982), and identified as the short
arm of chromosome 3 (3S) by Giemsa banding technique (Singh, 1981; Singh
and Tsuchiya, 1981, 1982a,b).
In this note the results of telotrisomic analysis of three genes with
the newly obtained telotrisomic for 3S (Triplo 3S) are reported. Three
genes used in this experiment are as follows:
BGS uz uzu or semi-brachytic, recessive
BGS al albino lemma, recessive
BGS ac albino seedling, recessive
Analysis of uz: The gene uz was previously located on
chromosome 3 (Robertson, 1971). By telotrisomic analysis this gene was
associated with a specific arm of chromosome 3 (Tsuchiya and Singh, 1982).
Further tests have been conducted to obtain the definite association of
uz with one arm of chromosome 3. The segregation ratios were observed
in the F2 generation (Table 1).
Table 1. Segregation ratios in F2 generation from
crosses between telotrisomic 3S and three marker genes.
The segregation ratios in diploid, telotrisomic and total population
fit to disomic 3:1 ratios and an appreciable number of recessive homozygotes
were found in trisomic portion. This clearly indicates that the gene uz
is not located in the short arm of chromosome 3 but located in the long
arm (3L). This is in agreement with recent results (Singh and Tsuchiya,
1982b; Tsuchiya, 1981).
Analysis of al: The gene al has also been associated with
chromosome 3 (Robertson, 1971). It was later studied by means of telotrisomic
analysis and was located in the presumed short arm (3S)* of chromosome
3 (Tsuchiya and Singh, 1982) [* This identification was changed to 3L (long
arm) by Singh and Tsuchiya 1982, TAG. (In press)]. In this study the gene
al was studied by telotrisomic analysis with Triplo 3S. As shown
in Table 1, the segregation ratios in the F2 generation did not fit a 3:1
disomic ratio and no recessive homozygotes were found in the trisomic portion.
This result confirms the association of al with the short arm of
chromosome 3 (3S).
Analysis of ac: The gene ac has
been reported to be located in the short arm of chromosome 3 with the following
linkage data (Robertson, 1963):
The telotrisomic analysis of this gene with the new Triplo 3S showed
disomic 3:1 segregation ratios in the total population as well as diploid
and trisomic portions with an appreciable number of homozygous recessives
the telotrisomic portion. These results clearly indicated that the gene
ac is not associated with the telocentric chromosome
(3S) used in this experlment but is located in the opposite arm (3L), or
the segment carrying ac in the 3S is deficient.
Robertson, D. W. 1963. Barley Genetics I (Proc. 1st Intern. Barley Genet.
Robertson, D. W. 1971. Barley Genetics II (Proc. IInd Intern. Barley
Singh, R. J. 1981. BGN 11:84-85.
Singh, R. J. and T. Tsuchiya. 1974. BGN 4:66-69.
Singh, R. J. and T. Tsuchiya. 1977. Z. Pflanzenzuchtg 78:327-340.
Singh, R. J. and T. Tsuchiya. 1981a. BGN 11:69.
BGN 12 toc
BGN Main Index