Development and Molecular Cytogenetic Identification of a New Wheat- Keng Translocation Line Resistant to Powdery Mildew.

Keng, a wild relative of common wheat with many desirable traits, is an invaluable source of genetic material for wheat improvement. Few wheat- translocation lines resistant to powdery mildew have been reported. In this study, a wheat- line, E24-3-1-6-2-1, was generated distant hybridization, ethyl methanesulfonate (EMS) mutagenesis, and backcross breeding. A chromosome karyotype of 2 = 44 was observed at the mitotic stage in E24-3-1-6-2-1. Genomic hybridization (GISH) analysis revealed four translocated chromosomes in E24-3-1-6-2-1, and chromosome-specific marker analysis showed that the alien chromosome fragment was from the 4Ns chromosome. Moreover, fluorescence hybridization (FISH) analysis demonstrated that reciprocal translocation had occurred between the 4Ns chromosome and the wheat 3D chromosome; thus, E24-3-1-6-2-1 carried two translocations: T3DS·3DL-4NsL and T3DL-4NsS. Translocation also occurred between wheat chromosomes 2A and 4A. At the adult stage, E24-3-1-6-2-1 was highly resistant to powdery mildew, caused by prevalent pathotypes in China. Further, the spike length, numbers of fertile spikelets, kernels per spike, thousand-kernel weight, and grain yield of E24-3-1-6-2-1 were significantly higher than those of its wheat parent 7182 and addition line 24-6-3-1. Thus, this translocation line that is highly resistant to powdery mildew and has excellent agronomic traits can be used as a novel promising germplasm for breeding resistant and high-yielding cultivars.