The genetic relationship between barley leaf rust resistance genes located on chromosome 2HS
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Four seedling leaf rust resistance genes (Rph14, Rph15, Rph16 and Rph17) described in barley are located on chromosome 2HS. A fifth, present in barley accession HOR 1063, was reported to map to the same region as Rph16. A comprehensive analysis of the allelic relationship between Rph14, Rph15, Rph17 and RphHOR1063 was undertaken. Two additional genotypes (HOR 15560 and Zhu 4) that were initially thought to carry Rph16 were also included. While no segregation was observed in F2 populations derived from crosses between PI 584760 (carrying Rph14), PI 355447 (carrying Rph15), Zhu 4 and HOR 1063, the lines did exhibit differential reactions across 10 Australian Puccinia hordei pathotypes. This suggests that the Rph14 locus may be complex. An evaluation of F3 populations confirmed that resistance genes in Zhu 4 and in HOR 1063 were allelic to both Rph14 and Rph15, however A susceptible line was found among F3 progeny of the cross PI 584760/PI 355447, suggesting that Rph14 and Rph15 may be independent. Rph17 and the gene present in HOR 15560 were shown to be independent of each other and of Rph14 and Rph15. The response of HOR 15560 across an array of P. hordei pathotypes revealed that it possesses the same specificity as Rph1. Because the resistance in Zhu 4 and HOR 1063 were shown to be allelic to Rph14, they should be designated Rph14.am and Rph14.an, respectively.
KeywordsHordeum vulgare Barley leaf rust Test of allelism Resistance
This research was supported by the Australian Grains and Research Development Corporation through a Postgraduate Research Scholarship (GRS139). The authors would also like to thank Mr Matthew Williams and Mr Paul Kavanagh for valuable technical support.
- Chicaiza O, Franckowiak JD, Steffenson B (1996) New sources of resistance to leaf rust in barley VIOC + VII International Barley Genetics Symposium, 706, Vol. Poster # 307Google Scholar
- Franckowiak JD, Jin Y, Steffenson BJ (1997) Recommended allele symbols for leaf rust resistance genes in barley. Barley Genet Newsl 27:36–44Google Scholar
- McIntosh RA, Wellings CR, Park RF (1995) Wheat rusts: an atlas of resistance genes. Kluwer Academic Publishers, LondonGoogle Scholar
- Roane CW, Starling TM (1967) Inheritance of reaction to Puccinia hordei in barley II. Gene symbols for loci in differential cultivars. Phytopathology 57:66–68Google Scholar
- Steffenson BJ, Jin Y (1996) A multi-allelic series at the Rph2 locus for leaf rust resistance in barley. Cereal Rusts Powdery Mildews Bull 24:74–75Google Scholar
- Tuleen IA, Mcdaniel ME (1971) Location of genes Pa and Pa5. Barley Newsl 15:106–107Google Scholar