Development and molecular cytogenetic identification of a new wheat-Psathyrostachys huashanica Keng translocation line with resistances to stripe rust

Psathyrostachys huashanica Keng (2n = 14, NsNs), a wild relative of common wheat, is an excellent gene source for wheat improvement because of its strong disease resistance, drought tolerance, and high tillering capacity. In this study, one additional line E3-6-4 (2n = 44) and E3-6-4 with high resistance to stripe rust were used in the hybrid progeny of common wheat parent 7182 and P. huashanica Keng, and the BC1F3 offspring of the wheat parent 7182 were used as research objects. We revealed nine distinct chromosome composition types through Genome in situ hybridization analysis. Among these, two homozygous translocation lines were identified: 2 L (2n = 42) and 2 S# (2n = 44). Fluorescence in situ hybridization analysis, together with expressed sequence tag–sequence-tagged site markers, simple sequence repeats, and a wheat liquid-phase microarray, revealed that 2 L carries a 3DS·3DL-2NsL translocation. Similarly, the 2 S# type was identified as 3DL·2NsL-2NsS. Results of the 55 K single-nucleotide polymorphism microarray analysis indicated that the translocation breakpoints were located between 445.63 and 451.69 Mb on wheat chromosome 3DL. The translocation line 3DS·3DL-2NsL demonstrated superior performance and stronger resistance to stripe rust than 7182, whereas 3DL·2NsL-2NsS showed characteristics more similar to E3-6-4 but was moderately susceptible. Overall, our results suggest that the 2Ns chromosome of P. huashanica likely harbors stripe rust resistance gene located on the 2NsL segment in the 3DS·3DL-2NsL translocation line. This line provides a promising parental resource for breeding stripe rust–resistant wheat and may contribute to improved yield-related traits, pending multi-environment yield evaluation.