EVALUATION OF RESISTANCE TO 5 ISOLATES OF PUCCINIA-CORONATA F-SP LOLII IN 19 PERENNIAL RYEGRASS CULTIVARS

This paper seeks to provide information on the differences in resistan ce to Puccinia coronata f. sp. lolii of the many perennial ryegrass (L olium perenne) cultivars available in Australia, and on the variation in resistance to this pathogen within these cultivars. This informatio n will help farmers to select crown rust resistant cultivars suited to their area, and indicate to perennial ryegrass breeders the diversity of crown rust resistance within the cultivars and lines screened. Twe nty genotypes of 14 cultivars and 5 advanced breeding lines of perenni al ryegrass were screened for their reaction to 5 isolates of P. coron ata f. sp. lolii. The isolates were collected from South Australia, so uthern Queensland, and 3 separate regions of Victoria. Tasdale, Victor ian, Martlet, Tasmanian No. 1, and D1 were significantly (P < 0 . 05) more susceptible to crown rust than all other cultivars and lines. Emb assy, D4, and D16 were the most resistant of the 19 cultivars and line s screened. Within all cultivars and lines there was significant (P < 0 . 05) difference between genotypes in their susceptibility to P. cor onata f. sp. lolii. This type of screening for genotype reaction could enable differential test plants to be selected for determining the pr esence of P. coronata f. sp. lolii pathotypes, an area that requires f urther research.