EFFECTIVENESS OF PA GENES ON PARTIAL RESISTANCE TO BARLEY LEAF RUST AT ADULT STAGE

Screening two groups of barley genotypes for partial resistance in the adult stage against two virulent physiologic races of Puccinia hor­dei Otth, the causal organism of barley leaf rust was carried out under greenhouse conditions. The first group consisted of seventeen geno­types with known Pa genes, while the second group consisted of fifteen cultivars with unknown genes for resistance. Rust severity, area under disease progress Curve (AUDPC), latent period (LP), infection frequency (IF), infectious period (IP) and pustule size (PS) were estimated for all barley entries. Results indicated that cultivars Quinn (Pa2     Pa5), Gold (Pa4), Peruvian (Pa2 loucus) and Estate (Pa3) can be grouped as slow-rusting with longer (LP), less (IF), shorter (IP) and restricted (PS), in addition to the less ALJDPC. Cultivars which showed the same trend may carry these genes for partial resistance. These cultivars can be included in the breeding program.