Recent pathotype development of New Zealand cereal rust populations
Rust diseases are serious threats to New Zealand cereal crops. Beside the use of fungicides, resistant varieties are an important option for managing these diseases. Changes in rust pathotypes commonly occur due to mutations in existing populations or exotic incursions. Information on these changes is the basis of gene-based disease management. Rust-infected leaves were collected from cereal crops from 2012 to 2015. The pathotypes of these and some historic samples were determined in glasshouse studies, using specific differential host sets. Eight pathotypes of Puccinia triticina (Pt, causal agent of wheat leaf rust), five of P. striiformis f. sp. tritici (Pst, causal agent of wheat stripe rust) and two of P. hordei (Ph, causal agent of barley leaf rust) were identified. The Pst â€˜WAâ€™ pathotype was most frequently found. Wheat varieties â€˜Empressâ€™ and â€˜Torchâ€™, previously resistant to Pt, were found to be susceptible to leaf rust for the first time. The â€˜WAâ€™ pathotype of Pst is likely to have arrived in New Zealand from Australia, and is now widespread. The two Pt pathotypes could have overcome resistance gene Lr24 in â€˜Empressâ€™ and â€˜Torchâ€™.
Braithwaite M, Cromey MG, Saville DJ, Cookson T 1998. Effects of fungicide rates and timing on control of stripe rust in wheat. Proceedings of the 51st New Zealand Plant Protection Conference, Quality Hotel, Hamilton, New Zealand, 11â€“13 August, 1998: 66â€“70.
Cromey MG 1992. A new pathotype of Puccinia striiformis in New Zealand with increased pathogenicity to wheat cultivars with the adult plant resistance gene Yr14. Australasian Plant Pathology 21: 172â€“174.
Cromey MG 2013. New lineage of stripe rust is virulent on triticale. In: From the Ground Up, Templeton. The Foundation for Arable Research. Pp. 9.
Cromey MG, Viljanen-Rollinson SLH 1995. Virulence of Puccinia hordei on barley in New Zealand from 1990 to 1993. New Zealand Journal of Crop and Horticultural Science 23: 115â€“119.
Cuddy W 2016. The wheat stripe rust pathogen in Australia - pathogenic variation and pathotype designation. https://rustbust.com.au/wp-content/uploads/2013/10/Cereal-Rust-Report-2016-Vol-14-Issue-2.pdf (January 2018).
Doling DA, Doodson JK 1968. The effect of yellow rust on the yield of spring and winter wheat. Transactions of the Bristish Mycological Society 51: 427.
HovmÃ¸ller MS, Walter S, Bayles RA, Hubbard A, Flath K, Sommerfeldt N, Leconte M, Czembor P, Rodriguez-Algaba J, Thach T, Hansen JG, Lassen P, Justesen AF, Ali S, Vallavieille-Pope C 2016. Replacement of the European wheat yellow rust population by new races from the centre of diversity in the near-Himalayan region. Plant Pathology 65: 402â€“411.
Huerta-Espino J, Singh RP, German S, McCallum BD, Park RF, Chen WQ, Bhardwaj SC, Goyeau H 2011. Global status of wheat leaf rust caused by Puccinia triticina. Euphytica 179: 143â€“160.
McIntosh RA, Wellings CR, Park RF 1995. Wheat rusts: an atlas of resistance genes. CSIRO Publishing, Melbourne, Australia.
Murray GM, Ellison PJ, Watson A 1995. Effects of stripe rust on the wheat plant. Australasian Plant Pathology 24: 261â€“270.
National Institute of Water and Atomospheric Research 2018. Seasonal Climate Summaries. https://www.niwa.co.nz/climate/summaries/seasonal (April 2018).
Park RF 2013. Cereal rust report season 2013. New barley leaf rust pathotype detected in Western Australia. The University of Sydney, Plant Breeding Institute, Cobbity.
Park RF 2015. Long term surveys of pathogen populations underpin sustained control of the rust diseases of wheat in Australia. Journal and Proceedings of the Royal Society of New South Wales 148: 15â€“27.
Park RF, Wellings CR 1992. Pathogenic specialisation of wheat rusts in Australia and New Zealand in 1988 and 1989. Australasian Plant Pathology 21: 61â€“69.
Park RF, Mohler V, Nazari K, Singh D 2014. Characterisation and mapping of gene Lr73 conferring seedling resistance to Puccinia triticina in common wheat. Theoretical and Applied Genetics 127: 2041â€“2049.
Samborski D 1985. Wheat leaf rust. In: Roelfs AP, Bushnell WR eds. The Cereal Rusts. Academic Press, Florida, USA. Pp. 39â€“59.
Steele KA, Humphreys E, Wellings CR, Dickinson MJ 2001. Support for a stepwise mutation model for pathogen evolution in Australasian Puccinia striiformis f. sp. tritici by use of molecular markers. Plant Pathology 50: 174â€“180.
Wellings CR, McIntosh RA 1990. Puccinia striiformis f. sp. tritici in Australasia - pathogenic changes during the first 10 years. Plant Pathology 39: 316â€“325.
Wellings CR, Wright DG, Keiper F, Loughman R 2003. First detection of wheat stripe rust in Western Australia: evidence for a foreign incursion. Australasian Plant Pathology 32: 321â€“322.
Wellings CR 2007. Puccinia striiformis in Australia: a review of the incursion, evolution, and adaptation of stripe rust in the period 1976-2006. Australian Journal of Agricultural Research 58: 567â€“575.