EFFECTS OF TEMPERATURE ON THE RESPONSE OF SOME AUSTRALIAN WHEAT CULTIVARS TO PUCCINIA-STRIIFORMIS F-SP TRITICI

The response of 83 Australian wheat cultivars to Puccinia striiformis f. sp. tritici was tested at the seedling stage under controlled condi tions of low (18/5-degrees-C) and high (24/15-degrees-C) post-inoculat ion temperature. Twenty cultivars differed in their response to P. str iiformis f. sp. tritici at high and low post-inoculation temperatures, and in all of these cases a shift toward resistance at higher tempera tures was recorded. Detailed studies made on a selection of 13 cultiva rs confirmed these results and further indicated that the high tempera ture treatment used did not adversely affect pathogen development in s usceptible cultivars. The resistance observed in the wheat cultivars C ook, Timgalen, and Suneca at higher post-inoculation temperatures was not affected by pre-inoculation temperature.