Inheritance and genetic mapping of stem rust resistance of wheat line X117-1
Abstract
Wheat (Triticum aestivum L.) stem rust caused by Puccinia graminis f.sp. tritici (Pgt) is one of the main disease of wheat worldwide. A new Pgt virulence genotype, Ug99, identified in Uganda in 1999, has been recognized as a major threat to wheat production. A plant selection (-1) of the Chinese spring wheat line X117 exhibited a moderate level of stem rust resistance to Ug99 in a test carried out by Dr. Yue Jin in USDA-ARS Cereal Disease Lab, St. Paul, MN. A recombinant inbred population of random lines developed by single seed descent from the cross of ‘ Xing117-1 x OK3040’ were tested in the field for two years, 2009 & 2010, against local isolates of Pgt at Lafayette, Indiana. Genetic analyses in both tests indicated that resistance of spring wheat line Xing117-1 is controlled by a single dominant gene. A total of 432 SSR markers were used on the resistant and susceptible parents for polymorphism and 93 polymorphic markers were identified between the resistant and susceptible parents. Bulks of respectively, 8 resistant and 8 susceptible lines were constructed separately by mixing equal quantities of genomic DNA of the respective subset of 8 resistant lines and 8 susceptible lines. SSR markers that were polymorphic on the parent lines were screened on bulks of, respectively, 8 resistant and 8 susceptible lines. Two markers Xwmc169 and Xwmc322, located on the long arm of chromosome 3A, appeared to be associated with the resistance and were screened on the entire 190 F 6:7 lines for linkage analysis. Molecular mapping using MAPMAKER 3.0 revealed that the gene was located on the long arm of chromosome 3A linked to and flanked by two markers Xwmc169 and Xwmc322 at 9.44 & 5.26 cM, respectively.
Degree
M.S.
Advisors
Ohm, Purdue University.
Subject Area
Plant biology|Genetics|Agriculture
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