A Database for Triticeae and Avena
II. 23. Induced asynapsis in barley.
G. Prasad*, S.N. Mathur**, and D.K. Tripathi*. *Department of Agricultural
Botany, S.D.J. Post Graduate College Chandesar, Azamgarh (U.P.) 276128;
and ** Gorakhpur University, Gorakhpur, India. "R"
An asynapsis mutant was isolated from the M2 generation of seeds of
barley cultivar DL 36 treated with 0.3 per cent diethylsulphate (DES).
No pairing of homologous chromosomes was observed at Pachytene, indicating
complete asynapsis. There was the presence of 14 univalents at diakinesis
(Fig. 1) and metaphase I. In 18.5 per cent of the metaphse I cells, the
univalents were scattered while in rest of the cells they were polar with
unequal distribution ranging from 0 to 14 towards each pole. In most of
the cases, there were unequal segregations at anaphase I, leading to the
formation of spores of unequal size (Fig. 2). Multipolar separations were
also observed with considerable frequencies.
Fig. 1. Diakinesis showing 14 univalents.
Fig. 2. Tetrad showing unequal size of microspores.
In barley, induced desynapsis of varying degrees has been reported by
Enns and Larter (1960), Sharma and Reinbergs (1974), Srivastava (1974)
and others. However, to the authors' knowledge, this may be the first report
of complete asynapsis in barley induced through chemical mutagen.
Enns, H. and E.N. Larter. 1960. Note on inheritance of Ds; A
gene governing meiotic chromosome behavior in barley. Can. J. Plant Sci.
Sharma, R.K. and E. Reinbergs. 1974. Cytogenetic analysis of a desynaptic
mutant in barley (Hordeum vulgare L.). Cytologia 39:77-81.
Srivastava, H.M. 1974. Radiation induced desynaptic mutants in barley.
BGN 10 toc
BGN Main Index