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 conditions of low (18/5-degrees-C) and high (24/15-degrees-C) post-inoculation temperature. Twenty cultivars differed in their response to P. striiformis f. sp. tritici at high and low post-inoculation temperatures, and in all of these cases a shift toward resistance at higher temperatures was recorded. Detailed studies made on a selection of 13 cultivars confirmed these results and further indicated that the high temperature treatment used did not adversely affect pathogen development in susceptible cultivars. The resistance observed in the wheat cultivars Cook, Timgalen, and Suneca at higher post-inoculation temperatures was not affected by pre-inoculation temperature.