|Kolmer, James - Jim|
Submitted to: Plant Disease
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/3/2004
Publication Date: 10/1/2004
Citation: Oelke, L.M., Kolmer, J.A. 2004. Characterization of leaf rust resistance in hard red spring wheat cultivars. Plant Disease. 88:1127-1133 Interpretive Summary: Leaf rust is a disease of wheat caused by the fungus Puccinia triticina. Hard red spring wheat cultivars grown in Minnesota and the Dakotas are attacked every year by this fungus. Wheat cultivars can be very resistant to the leaf rust fungus, if they have combinations of certain genes that give resistance to the fungus. The objective of this study was to determine which leaf rust resistance genes are likely present in a collection of hard red spring wheat cultivars. The wheat cultivars were tested for resistance in greenhouse and field plots with different races of the leaf rust fungus. Genes Lr1, Lr2a, Lr10, Lr16, Lr21, and Lr24 are likely present in the hard red spring wheat cultivars grown in Minnesota and the Dakotas. Wheat cultivars with combinations of Lr16, Lr21, and Lr24 had the best leaf rust resistance. This information will be directly useful to wheat breeders and plant pathologists to help develop wheat cultivars with high levels of leaf rust resistance.
Technical Abstract: Leaf rust, caused by Puccinia triticina Eriks, is the most common disease of wheat (Triticum aestivum L.) in the United States and worldwide. The objective of this study was to characterize seedling and adult leaf rust resistance in hard red spring wheat cultivars grown in Minnesota, North Dakota and South Dakota, and postulate the identity of the seedling leaf rust resistance genes in the cultivars. Twenty-six cultivars, near-isogenic lines of Thatcher wheat that differ for single leaf rust resistance genes, and three wheat cultivars with known leaf rust resistance genes were tested with 11 different isolates of leaf rust collected from the United States and Canada. The leaf rust infection types produced on seedling plants of the cultivars in greenhouse tests were compared to the infection types produced by the same isolates on the Thatcher near-isogenic lines to postulate which seedling leaf rust resistance genes were present. Seedling leaf rust resistance genes Lr1, Lr2a, Lr10, Lr16, Lr21 and Lr24 were postulated to be present in spring wheat cultivars. Seedling genes Lr3, Lr14a and Lr23 were likely present in some cultivars, but could not be clearly identified in this study. Most of the cultivars had some level of adult plant leaf rust resistance, most likely due to Lr34. Cultivars that had seedling resistance genes Lr1, Lr2a, Lr10, and / or Lr16, had poor to intermediate levels of leaf rust resistance in field plots, while cultivars with combinations of Lr16, Lr24 and adult plant resistance were highly resistant.