Molecular cytogenetic identification of newly synthetic Triticum kiharae with high resistance to stripe rust

Six new amphiploids, Triticum kiharae Dorof. et Migusch. (2n = 6x = 42, A(t)A(t)GGDD), are described in this study. They were developed by the chromosome doubling of F-1 hybrid crosses between Triticum timopheevii Zhuk. (A(t)A(t)GG) with high resistance to stripe rust and Aegilops tauschii Cosson (DD) by colchicine treatment. These amphiploids showed a high level of fertility of 68-80% and exhibited relatively normal chromosome pairing in meiotic metaphase I. Individual chromosomes of T. kiharae could be identified by multicolor fluorescence in situ hybridization using the combination of oligonucleotides probes Oligo-pSc119.2-1, Oligo-pTa535-1, and Oligo-pTa71-2. T. kiharae exhibited high resistance to predominant stripe rust races CYR34, CYR31, CYR32, CYR33, and SY11-4 both during the seedling and adult stages. However, high molecular weight glutenin subunits from Ae. tauschii parents were only partially expressed in the T. kiharae background. These T. kiharae lines provide novel materials to widen the genetic diversity of the common wheat gene pool.