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United States Department of Agriculture

Agricultural Research Service

Title: Production and Meiotic Analyses of Intergeneric Hybrids Between Durum Wheat and Thinopyrum Species.

Authors
item Jauhar, Prem
item Almouslem, A. - UNIV OF ALEPPO, SYRIA

Submitted to: International Triticeae Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 19, 1998
Publication Date: N/A

Interpretive Summary: Several of the wheat grasses, the wild relatives of wheat, have a host of genes for superior agronomic traits such as resistance to stem and leaf rusts, barley yellow dwarf virus, and Fusarium head blight. These grasses were crossed with Langdon, a superior cultivar of durum wheat, as female parent, and several hybrids were synthesized. Durum wheat has a gene called Ph1, located on chromosome 5B, that suppresses pairing between wheat chromosomes and grass chromosomes. Hybrids without Ph1 were produced using a Langdon substitution line LDN-5D(5B) (in which chromosome 5B carrying the Ph1 gene was substituted by chromosome 5D) as the female parent. The hybrids were perennial and phenotypically intermediate between the parental species. The hybrids lacking Ph1 showed extensive pairing between the chromosomes of the parental species. This pairing should facilitate the transfer of desirable alien genes into durum wheat. We have raised backcross progeny of some of the hybrids for further work on alien gene introgression.

Technical Abstract: Thinopyrum bessarabicum (2n=2x=14;JJ genome) and Th. curvifolium (2n=4x=28;J1J1J2J2) have a host of genes for superior agronomic traits such as resistance to stem and leaf rusts, barley yellow dwarf virus, and Fusarium head blight. These grass species (used as males) were crossed with Langdon (LDN), a superior cultivar of durum wheat (Triticum turgidum L., 2n=4x=28;AABB genomes). Several hybrids with and without the homoeologous pairing suppressor gene, Ph1, were synthesized. Hybrids without Ph1 were produced by using a Langdon substitution line LDN-5D(5B) (in which chromosome 5B carrying the Ph1 gene was substituted by chromosome 5D) as the female parent. The F1 hybrids were perennial and phenotypically intermediate between the parental species. The hybrids lacking Ph1 showed extensive homoeologous chromosome pairing. Thus, in two triploid F1 hybrids (2n=3x=21;ABJ) between LDN-5D(5B) and Th. bessarabicum, 60% of the chromosome complement showed chiasmatic association, a welcome feature from the breeding standpoint. Similarly, in hybrids between LDN-5D(5B) and Th. curvifolium 48% of the complement showed pairing. Relatively high pairing (31.4 to 36.1%) was also observed in the presence of Ph1 in some durum x Th. curvifolium hybrids, presumably because of the partial inactivation of Ph1. Data on chromosome pairing are presented, intergenomic relationships briefly described, and possibility of gene transfer into durum wheat discussed.

Last Modified: 7/22/2014
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