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Triticale (× TriticosecaleWittmack) is a commercial hybrid harboring wheat (Triticumsp.) and rye (Secale cerealeL.) genomes. The limited genetic diversity of this crop resulted in the collapse of fungal disease resistance. Leaf rust disease, caused by Puccinia triticinaEriks., is reported to reduce the triticale yield significantly (more than 30%). There is a need to enlarge the genetic variability of this crop including leaf resistance genes. The main aim of this research was to evaluate the leaf rust resistance of the offspring of translocation lines of triticale carrying chromatin of Ae. tauschiiand Ae. kotschyi. A reaction of seedlings of 200 plants of two triticale-Aegilopstranslocation lines (Bogo-2Dt.2R and Sekundo-2Sk.2R) was compared after inoculation with a natural mixture of P. triticinaraces, specific to triticale in controlled condition. Before inoculation, each plant was screened using molecular cytogenetics and molecular markers linked to leaf rust resistance genes. The presence of Aegilopschromosome segments was confirmed using genomic in situ hybridization (GISH). Lr39and Lr54leaf rust resistance genes were identified using Xgdm35and S14molecular markers, respectively. After inoculation, a significant improvement of resistance severity was observed in Sekundo-2Sk.2R in comparison with triticale cv. Sekundo plants. The resistance level of Bogo-2Dt.2R did not differ compared with triticale cv. Bogo plants. It was shown that Lr39gene did not increase the leaf rust resistance level of triticale cv. Bogo.

This paper shows the results of effective uses of a molecular cytogenetics toolbox and molecular marker to transfer leaf rust resistance genes from Aegilops tauschii× Secale cereale(DDRR, 2n = 4x = 28) amphiploid forms to triticale cv. Bogo (AABBRR, 2n = 6x = 42). The molecular markers of resistance genes and in situ hybridization analysis of mitotic metaphase of root meristems confirmed the stable inheritance of chromosome 3D segments carrying Lr32from the BC2F2to the BC2F5generation of (Ae. tauschii× S. cereale) × triticale hybrids. The chromosome pairing analysis during metaphase I of meiosis of BC2F4and BC2F5hybrids showed increasing regular bivalent formation of 3D chromosome pairs and decreasing number of univalents in subsequent generations. The results indicate that using amphiploid forms as a bridge between wild and cultivated forms can be a successful technology to transfer the D-genome chromatin carrying leaf rust resistance genes into triticale.