A Database for Triticeae and Avena
Ditelotetrasomics (2n=14+2 homologous telocentric chromosomes) have
been developed in barley. So far, ditelotetrasomics were obtained only
for short arms; ditelo 1S (Tsuchiya, 1969; Fedak and Helgason, 1970),
ditelo 3S, ditelo 5S, ditelo 6S, and ditelo 7S. Plants of ditelo 2S were
found several times, but were too weak to set seed after heading (Wang
and Tsuchiya, 1988). All the ditelotetrasomics found were derived from
the selfed progenies of monotelotrisomics, and the ratios were shown in
Ditelotetrasomic plants were also found for the long arms of
chromosome 2 (Riley and Tsuchiya, unpublished) and chromosome 4 (Wang and
Tsuchiya, unpublished; Tsuchiya, unpublished). However, ditelo 2L died at
early growing stage and ditelo 4L showed low seed fertility. No other
ditelotetrasomics for the long arms have been found or reported.
The frequency of ditelotetrasomic plants observed is different for
different telosomes. Furthermore, for telotrisomic 1S and 3S, no
ditelotetrasome was obtained in the progenies of two-rowed type
monotelosomes; all ditelotetrasomes were obtained in the six-rowed type.
Fedak, G., and S.B. Helgason. 1970. The cytogenetics of ditelotetrasomic
line in barley. Can. J. Genet. Cytol. 12:553-559.
Singh, R.J., and T. Tsuchiya. 1977. Morphology, fertility and
transmission in seven monotelotrisomics of barley. Z. Pflanzenzuchtg.
Tsuchiya, T. 1969. Status of studies of primary trisomics and other
aneuploids in barley. Genetica 40:216-232.
Wang, S., and T. Tsuchiya. 1988. Study of ditelotetrasomics for the
short arm of chromosome 2 (ditelo 2S) in barley. BGN 18:20-21.