Hexaploid triticales from hybrids of 'Langdon' durum D-genome substitutions with 'Gazelle' rye

Abstract

The formation of unreduced gametes in some hybrids between disomic D-genome substitutions (DS) of durum wheat cv. Langdon' and rye provides a convenient approach for the rapid introduction of D-genome chromosomes into hexaploid triticale. Meiotic pairing at metaphase I and seed fertility in spontaneous and colchicine-induced amphidiploids derived from F, hybrids between a set of Langdon' DS and 'Gazelle' rye were analysed. The purpose was to determine the effects of the substitution of D-genome chromosomes for their A- and B-genome homoeologues on hexaploid triticale and to select stable disomic D-genome substitutions of hexaploid triticale. The results showed that the disomic substitutions with D-genome slightly increased the frequency of univalents (1.0-3.13) compared with the 'Langdon' control primary hexaploid triticale (0.76). Substitutions 2D(2A) and 3D(3B) were partly desynaptic. The substitutions 1D(1A), 1D(1B) and 7D(7B) exhibited high seed fertility but the others had decreased fertility. Except for 2D(2A), 5D(5A), 3D(3B) and 5D(5B), 10 of the 14 possible hexaploid triticale D-genome disomic substitutions have been obtained. The results suggest that the poor compensation ability of some D-genome, chromosomes for their homoeologous A- and B-genome chromosomes is a major factor affecting meiotic stability and fertility in the hexaploid triticale D-genome substitutions.