Common bunt (CB), caused by Tilletia caries and T. foetida, and dwarf bunt (DB), caused by T. controversa, are particularly destructive diseases of wheat grown under organic (low-input) production conditions and negatively affect both grain yield and quality. A total of 16 race specific bunt resistance genes have been proposed to date. Thereof, only Bt9 and Bt10 have been mapped so far. A mapping and two validation populations comprising 176 recombinant inbred lines were evaluated for CB and DB in artificially inoculated field trials. The mapping population was derived from the cross of the Bt12 carrier PI119333 and the susceptible cultivar ‘Rainer’. The population was genotyped with the Illumina 15 K SNP chip and the major QTL QBt.ifa-7DS representing Bt12 was identified on chromosome 7DS, explaining 39% and 14% of the phenotypic variation for CB and DB resistance, respectively. Selected SNP markers were turned into Kompetitive Allele-Specific (KASP) markers and used to validate Bt12 in two independent validation populations. These markers can be used for introgressing Bt12 into regionally adapted elite breeding material.

中文翻译：

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小麦地方品种 PI119333 的普通和矮短短打抗性基因 Bt12 的遗传定位

由 Tilletia 龋病和 T. foetida 引起的普通短打 (CB) 和由 T. controversa 引起的矮短打 (DB) 是在有机（低投入）生产条件下生长的小麦特别具有破坏性的病害，并对谷物产量产生负面影响和质量。迄今为止，总共提出了 16 个种族特异性短打抗性基因。其中，目前仅映射了 Bt9 和 Bt10。在人工接种的田间试验中，对包含 176 个重组自交系的作图和两个验证群体的 CB 和 DB 进行了评估。定位群体来自 Bt12 载体 PI119333 和易感品种“Rainer”的杂交。使用 Illumina 15 K SNP 芯片对群体进行基因分型，并在染色体 7DS 上鉴定了代表 Bt12 的主要 QTL QBt.ifa-7DS，分别解释了 CB 和 DB 抗性表型变异的 39% 和 14%。选定的 SNP 标记被转化为竞争性等位基因特异性 (KASP) 标记，并用于在两个独立的验证群体中验证 Bt12。这些标记可用于将 Bt12 渗入区域适应的优良育种材料中。