A primary trisomic for chromosome 3 in a 6-rowed barley

Abstract

The trisomic plant isolated from gamma-irradiated barley material was phenotypically different from the normal diploid. The leaves of the trisome were narrow, margins rolled and light green in colour. Ear heads were also short, narrow and irregular. Ovule sterility (42.88 per cent) was relatively higher than pollen sterility (23.47 per cent). Cytological examination at metaphase I revealed 6II+1III, 7II, +1I and 6II+3I. The trivalents were chains of 3 and V, Y, frying pan and Q shaped indicating it to be a primary trisomic. The trisome was crossed with a set of translocation homozygotes and the cytology of the F1 hybrids was studied. This revealed that it was a trisomic for chromosome 3. However, the present trisomic looked different from the pale trisomic for chromosome 3 described by Tsuchiya in 2-rowed barley. Trisomics occurred more frequently in the progeny of smaller seeds of trisomic plants. Transmission rate of the extra chromosome through ovule was high while it was nil through pollen. © 1973, Japan Mendel Society, International Society of Cytology. All rights reserved.