THE USE OF BULK SEGREGANT ANALYSIS TO IDENTIFY A RAPD MARKER LINKED TO LEAF RUST RESISTANCE IN BARLEY

An F-2 population from a cross between barley accession Q21861 and the Australian barley variety 'Galleon' was used to develop RAPD markers for resistance to barley leaf rust (Puccinia hordei). Resistant and susceptible DNA bulks were constructed following the classification of F-2 plants by leaf rust infection type. Bulked segregant analysis was then used to identify a 2.7-kb marker, designated OU02(2700) and located approximately 12cM from RphQ, a leaf rust resistance gene in Q21861. The marker was generated by PCR with the oligonucleotide primer OPU-02 (Operon). Infection types of F-3 progeny were used to confirm assignment of F-2 genotypes. OU02(2700) was shown, retrospectively, to be useful in the identification of individual F-2 plants that had been originally misclassified as having susceptible infection types. Both the RAPD marker and RphQ will be potentially useful in the development of new barley cultivars.