Preliminary rust rankings released

The national rust research program has released preliminary disease response rankings for New South Wales varieties following the 2003 stripe rust outbreak.

Senior rust pathologist Dr Colin Wellings says that although the results are preliminary, they provide information on rust susceptibility, thus helping to decide which varieties to retain for seed.

Growing conditions in 2003 contributed to the most severe stripe rust outbreak for two decades in eastern Australia and saw the first ocurrence in the east of the new stripe rust strain that hit Western Australia in 2002. This resulted in many wheat varieties showing less than expected resistance to the disease.

“While the preliminary data give a basis for expected disease responses, the actual response of a variety will depend on many factors, including the strain of rust occurring at a particular location,” Dr Wellings says. “We’ve ranked the responses of NSW varieties to both the WA strain and the one associated with the variety H45Variety protected under the Plant Breeders Rights Act 1994 (110 E143 A+).

“While it is difficult to predict yield losses, it would be reasonable to expect that varieties with rankings of five or less will sustain loss when stripe rust is severe unless foliar fungicides are used.”

Growers are being encouraged to delete H45Variety protected under the Plant Breeders Rights Act 1994 from sowing options for 2004. The continued use of susceptible varieties, even with effective spray strategies in place, will form a considerable threat to those resistant wheats currently performing well. In the interests of the industry, rust susceptible wheats should be replaced as soon as possible.

Disease response rankings to stripe rust strains of NSW wheat varieties

For more information:
Dr Colin Wellings, 02 9351 8826, colinw@camden.usyd.edu.au

GRDC RESEARCH CODE US315, program 3