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ARS Home » Midwest Area » St. Paul, Minnesota » Cereal Disease Lab » Research » Publications at this Location » Publication #352482

Research Project: Cereal Rust: Pathogen Biology and Host Resistance

Location: Cereal Disease Lab

Title: Adult plant leaf rust resistance derived from Toropi wheat is conditioned by Lr78 and three minor QTL

Author
item Kolmer, James - Jim
item Bernardo, Amy - Kansas State University
item Bai, Guihua
item Hayden, Matthew - La Trobe University
item Chao, Shiaoman

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/2017
Publication Date: 1/15/2018
Citation: Kolmer, J.A., Bernardo, A.N., Bai, G., Hayden, M.J., Chao, S. 2018. Adult plant leaf rust resistance derived from Toropi wheat is conditioned by Lr78 and three minor QTL. Phytopathology. 108:246-253.

Interpretive Summary: Wheat is attacked by the leaf rust fungus, Puccinia triticina. Genes in wheat can provide resistance to this important pathogen and disease of wheat. The wheat cultivar Toropi, which was developed in Brazil, has had long lasting resistance to leaf rust for many years. The objective of this research was to determine on what chromosomes the leaf rust resistance genes in Toropi are found. Toropi had a major gene for leaf rust resistance on chromosome 5DS. Other genes with smaller effects on resistance were found on chromosomes 1BL, 3BS, and 4BS. The resistance gene on 5DS was a new gene and was designated as Lr78. Toropi can be used as a parent by wheat breeders and plant pathologists to improve the leaf rust resistance in wheat improvement programs.

Technical Abstract: Brazil, was noted to have long lasting leaf rust resistance that was effective only in adult plants. The objectives of this study were to determine the chromosome location of the leaf rust resistance genes derived from Toropi in two populations of recombinant inbred lines in a partial Thatcher wheat background. In the first population, a single gene with major effects on chromosome 5DS that mapped 2.2 cM distal to IWA6289, strongly reduced leaf rust severity in all three years of field plot tests. This gene for adult plant leaf rust resistance was designated as Lr78. In the second population, QTL with small effects on chromosomes 1BL, 3BS, and 4BS were found. These QTL expressed inconsistently over four years of field plot tests. The adult plant leaf rust resistance derived from Toropi involved a complex combination of QTL with large and small effects.