PATHOGENIC SPECIALIZATION OF PUCCINIA-RECONDITA F-SP TRITICI IN AUSTRALIA AND NEW-ZEALAND IN 1990 AND 1991

Levels of leaf rust on wheat and triticale were generally low througho ut the 1990 and 1991 wheat-growing seasons. The most commonly isolated pathotypes (pts) of Puccinia recondita f. sp. tritici isolated from a ll eastern states in Australia during 1990 were pts 104-2,3,(6),(7),11 and 104-1,2,3,(6),(7),11. The latter was recorded in Western Australi a for the first time in 1990. The most commonly isolated pts from New Zealand were 76-1,3, 76-1,3,5, 104-1,3, and 104-2,3,(6),(7),11. In 199 1, dry conditions throughout Queensland, New South Wales and Victoria reduced levels of leaf rust greatly. The most commonly isolated pt in all mainland states was either pt 104-2,3,(6),(7),11 or 104-1,2,3,(6), (7),11. Four pts (viz. 53-1,(6),(7),10,11, 104-1,3, 104-1,3,5 and 104- 2,3,(6),(7),11) were isolated at approximately equal frequencies from New Zealand samples. Leaf rust pts isolated for the first time in Aust ralasia were 53-(6),(7),10,11, 53-6,(7),9,10,11+ Lr10, 64-11, 104-2,3, 5,(6),(7),11 and 104-1,2,3,5,(6),(7),11 (isolated during 1990), and 10 -1,2,3,4,8, and 122-1,2,3,(6),(7),11 (isolated during 1991).