Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/20/2002
Publication Date: 7/16/2002
Citation: SINGH,S., BROWN GUEDIRA,G.L., GREWAL,T.S., DHALIWAL,H.S., NELSON,J.C., SINGH,H., GILL,B.S., MAPPING OF A RESISTANCE GENE EFFECTIVE AGAINST KARNAL BUNT PATHOGEN OF WHEAT, CROP SCIENCE, 2002. 106:287-292. Interpretive Summary: Karnal bunt (KB), caused by Tilletia indica Mitra (Syn. Neovossia indica (Mitra) Mundkar), is a disease of wheat (Triticum aestivum L.) that was first reported at Karnal in northern India in 1931. This disease was first detected in the U.S. in 1996 and was reported in the major wheat production area of the Southern Great Plains in 2001. Genetic resistance of the host plant is the most effective means of disease control. In this study, we have used molecular markers to analyze a population of wheat plants that segregate for resistance to Karnal bunt. Testing of lines with the disease was done at Punjab Agricultural University in the India and molecular marker analysis was performed in the U.S.. A chromosomal region that reduces disease by half was detected in the analysis. The molecular markers in this region may be used to develop Karnal bunt resistant wheat varieties.
Technical Abstract: A set of 130 wheat recombinant inbred lines (RILs) developed from a cross between parents susceptible (WL711) and resistant (HD29) to Karnal bunt (caused by Tilletia indica), were screened for three years with the pathogen populations prevalent in northern India. When 90 simple sequences repeats (SSR) and 81 amplified fragment length polymorphism (AFLP) loci were mapped on the RILs, markers on chromosomes 2A, 3B, 4B, and 7B accounted collectively for about one third of the variation in disease reaction. The genomic region of largest effect, identified on the long arm of chromosome 4B, reduced Karnal bunt disease by half in three different experiments and accounting for up to 25% of the phenotypic variation for KB reaction. A closely linked SSR marker, GWM538, may be useful in marker-assisted selection for Karnal bunt resistance in wheat.