(go to KOMUGI Home) (go to WIS List) (go to NO.80 Contents)

Wheat Information Service
Number 80: 26 - 31 (1995)

Spontaneous chromosome substitutions in hybrids of Triticum aestivum with T. araraticum detected by C-banding technique

E.D. Badaeva and B.S. Gill

Wheat Genetics Resource Center, Department of Plant Pathology, Kansas State University, Throckmorton Hall, Manhattan, KS 66506-5502, USA


Abstract

One hundred thirty-one plants representing twenty-nine families of Triticum aestivum cv. Wichita X T. araraticum hybrids were analyzed by the C-banding technique. Transfer of genetic material involved whole chromosome(s) or chromosome arms. Nine different types of chromosome substitution were found. The mean number of substitutions per karyotype was 1.86 (range 1-3). Substitutions involving G genome chromosomes occurred more frequently than A' genome chromosomes. Individual chromosomes also differed in the frequency of substitution. The most frequently substituted chromosome was 6G, while substitutions with 1At, 2At, 4At, 6At, 7At, 3G, and 7G were not recovered. A recombinant (rec) 7AS-7AtL chromosome was identified. The spectrum of substitutions was different from those in other T. aestivum x T. timopheevii hybrids, indicating that the genotype of the parental species determines the pattern of substitutions in their hybrids.


Introduction

Triticum araraticum Jakubz. is a wild tetraploid wheat with the genome formula AtAtGG. Morphologically similar to T. dicoccoides, T. araraticum differs from it in karyotype structure (Badaeva et al. 1986; Gill and Chen 1987; Jiang and Gill 1994). At present, there is no consensus opinion on the origin of these two wheat species. According to one hypothesis, T. dicoccoides and T. araraticum were derived from the common ancestor by introgressive hybridization with unknown diploid species (Gill and Chen 1987). On the other hand, there is much evidence that these species had independent origins (Jiang and Gill 1994).

Analysis of substitution types in common wheat x T. araraticum hybrids may provide an insight into genetic interrelationships between the A and B genomes of T. dicoccoides and the At and G genomes of T. araraticum. In addition, T. araraticum has agronomically valuable traits such as pest resistance and restorer genes for cytoplasmic male sterility and, as a consequence, may be used as a donor of these properties. The determination of chromosomal substitution patterns in the karyotypes of hybrids may be also useful in breeding work.

-->Next

(go to KOMUGI Home) (go to WIS List) (go to NO.80 Contents)