Monosomes and their Influence on Meiosis in ‘Holdfast’ (Triticum aestivum L.)

Abstract

Like ‘Chinese Spring’, ‘Holdfast’ is a hexaploid wheat (2n=42), and can be used in building a set of monosomic lines just as conveniently, for meiosis in it is not as stable as is to be expected in a stable commercial variety. Monosomics are regularly thrown out as a result of meiotic instability and as such several lines can be built up within comparatively a short time. In this paper eleven apparently different monosomic lines have been studied cytologically. The morphological features of the individual monosomes have been described and an attempt has been made to compare and identify these with the chromosomes in ‘Chinese Spring’.
Meiotic irregularities have been described in these monosomic lines and at first appear substantial and significant but when they are assessed against the background of ‘Holdfast’ these irregularities no longer seem to be of much significance. However, it may be said that all these monosomic lines are not similar in the type and to the extent to which they exhibit aberrant features in meiosis. Some lines produce appreciably more aberrant features than others whereas some seem to be even more regular than the parent variety itself.