Singh Sukhwinder, Bockus William W, Sharma Indu, Bowden Robert L
Department of Plant Pathology, Kansas State University, Manhattan 66506.
Department of Plant Breeding, Genetics and Biotechnology, Punjab Agricultural University, Ludhiana, India.
Plant Dis. 2008 Jan;92(1):91-95. doi: 10.1094/PDIS-92-1-0091.
Tan spot, caused by the fungus Pyrenophora tritici-repentis, causes serious yield losses in wheat (Triticum aestivum) and many other grasses. Race 1 of the fungus, which produces the necrosis toxin Ptr ToxA and the chlorosis toxin Ptr ToxC, is the most prevalent race in the Great Plains of the United States. Wheat genotypes with useful levels of resistance to race 1 have been deployed, but this resistance reduces damage by only 50 to 75%. Therefore, new sources of resistance to P. tritici-repentis are needed. Recombinant inbred lines developed from a cross between the Indian spring wheat cvs. WH542 (resistant) and HD29 (moderately susceptible) were evaluated for reaction to race 1 of the fungus. Composite interval mapping revealed quantitative trait loci (QTL) on the short arm of chromosome 3A explaining 23% of the phenotypic variation, and the long arm of chromosome 5B explaining 27% of the variation. Both resistance alleles were contributed by the WH542 parent. The QTL on 5BL is probably tsn1, which was described previously. The 3AS QTL (QTs.ksu-3AS) on 3AS is a novel QTL for resistance to P. tritici-repentis race 1. The QTL region is located in the most distal bin of chromosome 3AS in a 2.2-centimorgan marker interval. Flanking markers Xbarc45 and Xbarc86 are suitable for marker-assisted selection for tan spot resistance.
小麦黄斑病由真菌小麦根腐离蠕孢（Pyrenophora tritici-repentis）引起，会给小麦（Triticum aestivum）和许多其他禾本科植物造成严重的产量损失。该真菌的1号生理小种能产生坏死毒素Ptr ToxA和褪绿毒素Ptr ToxC，是美国大平原地区最普遍的生理小种。已推广了对1号生理小种具有有效抗性水平的小麦基因型，但这种抗性仅能将损害降低50%至75%。因此，需要新的抗小麦根腐离蠕孢的抗性来源。对由印度春小麦品种WH542（抗病）和HD29（中度感病）杂交培育出的重组自交系进行了对该真菌1号生理小种反应的评估。复合区间作图揭示了位于3A染色体短臂上的数量性状位点（QTL），其解释了23%的表型变异，以及位于5B染色体长臂上的QTL，其解释了27%的变异。两个抗性等位基因均由亲本WH542提供。5BL上的QTL可能是先前描述过的tsn1。3AS上的3AS QTL（QTs.ksu-3AS）是一个抗小麦根腐离蠕孢1号生理小种的新QTL。该QTL区域位于3AS染色体最远端的 bins 中，处于一个2.2厘摩的标记区间内。侧翼标记Xbarc45和Xbarc86适用于小麦黄斑病抗性的标记辅助选择。
