PG-II: PROGRESS IN DEVELOPING BREAD WHEAT RESISTANT TO BARLEY YELLOW DWARF VIRUSES USING SEROLOGICAL, MOLECULAR MARKER AND MOLECULAR CYTOGENETIC TECHNIQUES

Plant Genome II Conference

Town & Country Conference Center, San Diego, CA, January, 1994.

PROGRESS IN DEVELOPING BREAD WHEAT RESISTANT TO BARLEY YELLOW DWARF VIRUSES USING SEROLOGICAL, MOLECULAR MARKER AND MOLECULAR CYTOGENETIC TECHNIQUES

L. Bertschinger 1, M. D. H. M. William 1, N. Islam-Faridi 1, A. Cortes 1, D. Gonzalez de Leon 1, A. Mujeeb-Kazi 1, A. Comeau 2, K. M. Makkouk 3, H. Ohm 4, R. Appels 5. 1 CIMMYT, Apdo Postal 6-641, 06600 Mexico, D. F., Mexico; 2 Agriculture Canada, 2560 boul. Hochelaga, SteFoy Qc G1V 2J3, Canada; 3 JCARDA, P.0. Box 5466, Aleppo, Syria; 4 Dept. of Agronomy, Purdue University, West Lafayette, IN 47907, USA; 5 CSIRO, Division of Plant Industry, P.0. Box 1600, Canberra, ACT 2601, Australia.

Barley yellow dwarf viruses (BYDVS) are the most important viral pathogens in small grain cereals worldwide. Resistance to BYDVs (restricted infection and/or replication and/or invasion) [sensu J. 1. Cooper and A. T. Jones, Phytopathology 73:127-128 (1983)] has not been found in any true wheats. Recently, resistance has been transferred to bread wheat from 7hinopyrum intt@rmedium (Host) Barkworth & D. R. Dewey [Larkin, P. J. et a]. Acta Hort. 336 (in press) (1993)]. This germplasm is being characterized, genetically analyzed, and advanced at the International Maize and Wheat Improvement Center (CIMMYT). Genetic stocks are being developed for making the germplasm available to wheat improvement programs. In collaboration with other institutions, several innovative techniques are being exploited to characterize this germplasm and to develop tools for marker-assisted selection. Homozygous resistant lines were produced and identified by testing inoculated progenies with DAS-ELISA. It was confirmed by tissue-blot ELISA that the resistance of these lines to four BYDVs confers low virus concentrations but not immunity. Results of the detection of an RFLP (A600) in EcoRV-digested DNA of segregating, normally pairing hexaploid lines and of their parents correlated well with the presence of the resistance. A non-radioactive protocol was developed for the use of A600. Even if in most cases, resistant lines could be easily identified by using the A600, its slight cross-reaction with wheat DNA emphasizes the need for a more specific polymerase chain reaction-based marker assay for marker-assisted selection. DNA from the intermedium was physically mapped with fluorescent in-situ hybridization (FISH). Different translocation families were analyzed by FISH. Based on ELISA, A600 and FISH results, conclusions are drawn regarding the most appropriate way to transfer the resistance into a desired agronomic background.

Return to Previous Page or Intl-PAG Homepage