Molecular cytogenetic evidence for a high level of chromosome pairing among different genomes in Triticum aestivum : Thinopyrum intermedium hybrids

• Published in: Theoretical and applied genetics Vol. 102; no. 6-7; pp. 847 - 852
• Main Authors: CHEN, Q, CONNER, R. L, LAROCHE, A, AHMAD, F
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-05-2001; Berlin Springer Nature B.V
• Subjects: Biological and medical sciences; Chromosomes; Cytogenetics; Fundamental and applied biological sciences. Psychology; Genetics of eukaryotes. Biological and molecular evolution; Genomes; Hybridization; Pseudoroegneria libanotica; Pteridophyta, spermatophyta; Seeds; Thinopyrum intermedium; Triticum; Triticum aestivum; Vegetals and fungi; Monocotyledones; Gramineae; Chromosome pairing; Intergeneric hybridization; Angiospermae; Fluorescence in situ hybridization; Cytogenetics; Spermatophyta; Genome; Cereal crop; Triticum aestivum
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s001220000496

Intergeneric hybrids (ABDJJ^sup s^S genomes) were made between Triticum aestivum cv. Chinese Spring (CS) and Thinopyrum intermedium. Genomic in situ hybridization (GISH) using genomic DNA probes from Pseudoroegneria libanotica (Hackel) D.R. Dewey (genome S, 2n = 14) was used to study chromosome pairing among J, J^sup s^, S and wheat ABD genomes in the hybrids. It was shown that in the hexaploid (ABDJJ^sup s^S) hybrids, high pairing occurred among wheat chromosomes and among Thinopyrum chromosomes. A closer relationship was observed among the three genomes of Th. intermedium than among the three genomes of T. aestivum. It was further discerned that S genome chromosomes paired with J- and J^sup s^-genome chromosomes at a high frequency. The frequency of heterologous pairing between S and J or S and J^sup s^ chromosomes was higher than those between J and J^sup s^ chromosomes, indicating that the S-genome was more closely related with these two genomes. Our results provided direct molecular cytogenetic evidence for the hypothesis that S-genome chromosomes are genetically similar to the J-genome chromosomes and, therefore, genetic exchange between these genomes is possible. The discovery of a close relationship among S, J and J^sup s^ genomes provides valuable markers for molecular cytogenetic analyses using S-genomic DNA probes in monitoring the transfer of useful traits from Thinopyrum species into wheat.[PUBLICATION ABSTRACT]