Abstract
Robertsonian translocations (RobTs) in the progeny of triticale (×Triticosecale Wittmack) plants with monosomic substitution of Aegilops kotschyi chromosome 2Sk (2R) were investigated by fluorescence in-situ hybridization. Chromosome 2Sk of Ae. kotschyi is reported to possess many valuable loci, such as Lr54 + Yr37 leaf and stripe (yellow) rust resistance genes. We used a standard procedure to produce RobTs, which consisted of self-pollination of monosomic triticale plants, carrying 2R and 2Sk chromosomes in monosomic condition. This approach did not result in RobTs. Simultaneously, we succeeded in producing 11 plants carrying 2R.2Sk compensatory RobTs using an alternative approach that utilized ditelosomic lines of triticale carrying 2RS (short arm) and 2RL (long arm) telosomic chromosomes. Identification of molecular markers linked to Lr54 + Yr37 genes in the translocation plants confirmed that these resources can be exploited in current triticale breeding programmes.
Highlights
Hexaploid triticale (×Triticosecale Wittmack, 2n = 6x = 42, AABBRR) is one of the few artificial crops cultivated at a large scale
It was hypothesized that the presence of the 2R donor chromosomes in a telosomic condition would increase the frequency of Robertsonian translocations (RobTs) recovery (Figure 1b)
Many reports have shown that RobTs in wheat can arise by centromeric misdivision of univalents at AI, followed by segregation of the derived telocentric chromosomes to the same nucleus, and fusion of the broken parts [26,30,31]
Summary
Marais et al [20] identified the Lr54 and Yr37 leaf rust and stripe rust resistance genes, and developed aT2DS.2Sk L wheat-Ae. kotschyi translocation line. We postulated that the use of telosomic plants for cross-hybridization with plants carrying an alien-substitution will overcome the random process of centric break formation in the univalent (Figure 1b). This approach was used to transfer the Lr54 + Yr37 resistance genes into triticale cv. It was hypothesized that the presence of the 2R donor chromosomes in a telosomic condition would increase the frequency of RobTs recovery (Figure 1b). Ideogram of the two contrasting approaches for the recovery of Robertsonian translocations
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