Implications of the known wheat leaf rust pathotypes in WA

Please note: This content may be out of date and is currently under review.

This page provides information about known wheat leaf rust pathotypes in Western Australia (WA), including the new ones detected in 2013 and 2015. In the presence of the new pathotypes, several wheat varieties have had their disease resistance rating for leaf rust shifted towards greater susceptibility. As a result, disease management of these varieties will need to change, particularly in leaf rust prone areas. Growers and agronomists are encouraged to submit samples of any leaf rust finds to the Australian Cereal Rust Control Program for pathotype testing.

Leaf rust pathotypes detected in WA since 1990

In the past 25 years, since 1990, nine leaf rust pathotypes have been identified in Western Australia (WA) (Table 1). The dominant pathotypes over the last ten years have been stable and variety leaf rust rankings have not changed significantly in that time. Over that period statewide leaf rust epidemics occurred in WA in 1992 and in 1999. Regional outbreaks of leaf rust have developed regularly over that period.

In 2013, a new leaf rust pathotype was detected which was the first occurrence of virulence for the resistance genes Lr13, Lr17a, Lr17b, and Lr26 in WA. More information about this pathotype including where and when it was found is available on the 2013 New wheat leaf rust pathotype page and ACRCP Rust Report (Volume 11 Issue 6).

In 2015, another new leaf rust pathotype was detected in WA. The new pathotype differs from those detected previously in WA in being fully virulent on the complementary resistance genes Lr27+Lr31, the adult plant resistance gene Lr12, and in combining virulence for Lr1 with Lr13, Lr17a, and Lr26. More information about this pathotype including where and when it was found and the implications for wheat varieties is available on the 2015 New wheat leaf rust pathotype page and ACRCP Rust Report (Volume 13 Issue 4).

Table 1. Known wheat leaf rust pathotypes in WA (Source:Dr Robert Park, Australian Cereal Rust Control Program). Pathotype naming is a complicated system that does not relate to genes but to the rust response of four wheat genotypes that permit a standard race designation, and an additional 11 wheats used as Australian supplementary differentials.

Year

Pathotype name

Comments

1990

104-1,(2),3,(6),(7),11

Was common, less so now
1990

104-1,2,3,5,(6),(7),11

Rare
1993

122-1,2,3,(6),(7),11

Rare
1996

104-1,2,3,4,(6),(7),11

Rare
1998

104-1,2,3,(6),(7),11

Was common, less so now
2002

104-1,(2),3,(6),(7),11 +Lr37

Common (less since 2013 incursion)
2002

104-1,2,3,5,(6),(7),11

Rare
2013

76-1,3,5,7,9,10,12 +Lr37

New, introduced, becoming widespread
2015

104-1, 3, 4, 6, 7, 8, 10, 12 +Lr37

New, introduced, likely to become dominant eventually

What changes are there in wheat variety ratings to leaf rust?

Wheat varieties dependent on the resistance genes which are no longer effective are now expected to be more vulnerable to leaf rust infection by these strains.

  • After the 2013 pathotype incursion the following were rated moderately susceptible to susceptible (MSS): Mace, Wyalkatchem, Corack and Emu Rock. Bonnie Rock is now rated moderately resistant to moderately susceptible (MRMS). See wheat variety resistance ratings.
  • After the 2015 pathotype incursion there are expected to be further changes: Arrino, Binnu, Emu Rock, Envoy, Estoc, Grenade CL Plus, Mace, Tammarin Rock, and Zippy will be more vulnerable to leaf rust.

Current wheat variety resistance ratings to leaf rust are available (supersedes the tables in the 2015 wheat variety sowing guide). After further testing of varieties is conducted with the new 2015 pathotype this table will be updated and variety ratings will be available in the 2016 Wheat Variety Sowing Guide.

Contact information

Geoff.j Thomas
+61 (0)8 9368 3262
Ciara Beard
+61 (0)8 9956 8504
Kithsiri Jayasena
+61 (0)8 9892 8477
Andrea Hills
+61 (0)8 9083 1144
Page last updated: Tuesday, 22 November 2016 - 2:00pm