Inheritance and characterization of the new and rare gene Rph25 conferring seedling resistance in Hordeum vulgare against Puccinia hordei

In this study, we characterized and mapped a new and rare resistance gene (RphFT) in the Chinese barley variety Fong Tien'. RphFT, a dominant gene, was mapped to chromosome 5HL at a genetic position of 142.1 cM using DArT-seq markers. The gene was also confirmed to be present in Australian cultivar Yagan' based on allelic tests, and likely Lockyer' based on multipathotype tests. The genetic studies also confirmed the presence of Rph12 in Australian cultivar Baudin'. Rph12 is also located on chromosome 5HL close to RphFT, and the two loci were confirmed to be independent. Gene RphFT is of limited breeding value because it is effective to only one pathotype of P.hordei, 220P+ +Rph13 in Australia; nevertheless, it may play a role in controlling leaf rust if used in combination with other Rph genes. The locus symbol Rph25 is recommended for RphFT in accordance with the rules and numbering system of barley gene nomenclature.