ARS | Publication request: CYTOLOGICAL AND MOLECULAR CHARACTERIZATION OF WHEAT LINES WITH THINOPYRUM INTERMEDIUM CHROMOSOME ADDITIONS, SUBSTITUTIONS RESISTANT TO BARLEY YELLOW DWARF VIRUS

Submitted to: Cytologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 14, 1998
Publication Date: N/A

Interpretive Summary: Barley yellow dwarf virus (BYDV) is the most serious viral disease affecting wheat, and genes for resistance to BYDV have not been found in wheat. BYDV-resistant wheat lines containing an additional chromosome from Thinopyrum intermedium, a related BYDV-resistant wheatgrass species, and wheat lines in which a wheatgrass chromosome has replaced a wheat chromosome, have been characterized. The wheatgrass chromosomes in these lines that confer BYDV resistance appear to be the same alien chromosome. However, the wheatgrass chromosome adversely affects other properties of wheat such as the grain yield, the milling and baking quality of the flour, and increases the time from planting to harvest. Therefore the lines containing this wheatgrass chromosome were treated to break this chromosome into smaller fragments. Following this treatment a wheat line was identified which was BYDV resistant and had a reduced amount of the wheatgrass chromosome. This line is currently being used to incorporate BYDV resistance into superior wheat cultivars.

Technical Abstract: Barley yellow dwarf virus (BYDV) is the most serious viral disease affecting wheat and genes for resistance to BYDV have not been found in wheat. BYDV-resistant alien addition and alien substitution lines from Triticum aestivum x Thinopyrum intermedium (species of Agropyron complex) crosses were characterized and the production and partial characterization of translocations derived from them described. Chromosome pairing between two substitution lines showed that they had the same Th. intermedium chromosome. Likewise, two addition lines involved the same alien chromosome. In situ hybridization, using Thinopyrum intermedium genomic DNA as a probe, conformed that line P29 is a homozygous substitution line. Double monosomic seeds and self- pollinated seeds from monosomic alien addition plants were irradiated. M2 families were selected on the basis of their segregation for BYDV resistance to identify putative translocations. Using a Thinopyrum specific probe and wheat group 7 chromosome markers a BYDV-resistant translocation was identified for use in the breeding program.