General features of chromosome substitutions in Triticum aestivum x T. timopheevii hybrids

Abstract

Based on a C-banded chromosome analysis of Triticum aestivum x T. timopheevii hybrid lines, we developed a classification of the A(t) and G genome chromosomes that agrees with the standard genetic nomenclature of T. aestivum chromosomes. Transfer of genetic material from T. timopheevii to T. aestivum involved complete chromosomes, chromosome arms, or segments. Frequencies of chromosome substitution were highest for homoeologous group 2 and lowest for group 4. Moreover, B(G) substitutions were frequent compared to A(A(t)). The pattern of chromosome substitutions and rearrangements were unequal and depended on the genotype of the parental T. aestivum cultivar.

Tetraploid wheat species Triticum timopheevii and Triticum militinae in common wheat improvement

“…The A t and G genomes of timopheevii wheats can clearly be differentiated by the C-banding technique, the A t genome being only slightly banded by heterochromatin and the G genome, according to Badaeva et al (1991), containing more heterochromatin than any other wheat or Aegilops species. The assignment of individual A t and G genome chromosomes to homoeologous groups has been based on the similarity of chromosome banding patterns (Badaeva et al, 1986;Gill and Chen, 1987), chromosome pairing in interspecific hybrids with wheat (Gill and Chen, 1987) and compensating ability in spontaneous substitution lines (Badaeva et al, 1991;.…”

“…The assignment of individual A t and G genome chromosomes to homoeologous groups has been based on the similarity of chromosome banding patterns (Badaeva et al, 1986;Gill and Chen, 1987), chromosome pairing in interspecific hybrids with wheat (Gill and Chen, 1987) and compensating ability in spontaneous substitution lines (Badaeva et al, 1991;. Based on a C-banded chromosome analysis of T. aestivum × T. timopheevii hybrid lines, Badaeva et al (1991) developed a classification of the A t and G genome chromosomes in general use that agrees with the standard genetic nomenclature of T. aestivum chromosomes.…”

“…Badaeva et al (1991; analysed the general features of chromosome substitutions in T. aestivum × T. timopheevii hybrids obtained by different cross combinations and found that as a general rule A t genome chromosomes substituted for their A-genome counterparts, while G-genome chromosomes substituted for their B-genome homoeologues, the latter substitutions being more frequent.…”

“…The pattern and frequency of chromosomal substitutions is determined by the genotype of the parental common wheat cultivar (Shkutina et al,1988;Badaeva et al, 1991). Most frequently, substitutions involving 2B/2G, 6B/6G and 2A/2A t have been detected in T. aestivum × T. timopheevii hybrids with different wheat backgrounds (Badaeva et al, 1991;1995b;.…”

“…Most frequently, substitutions involving 2B/2G, 6B/6G and 2A/2A t have been detected in T. aestivum × T. timopheevii hybrids with different wheat backgrounds (Badaeva et al, 1991;1995b;.…”