Preliminary Observations on Resistance to Rust Diseases of Kentucky Bluegrass Ecotypes from Poland

Four hundred and forty-four ecotypes of Kentucky bluegrass (Poa pratensis L.) collected from Poland were screened for rust resistance. A ®eld experiment was established at Hof Steimke, DSV (Deutschen Saatve- redelung), Germany. The ecotypes originated from the Polish Gene Bank, IHAR ± Botanical Garden, Bydgoszcz. Sixty-two (13.9%) ecotypes that scored on average more than 5 were included in a group with high resistance. Ecotypes scored on average less than 5 were either included in a susceptible group (average scores 4.0±4.9) or a very susceptible group (average scores 2.0±3.9). There were 181 ecotypes in the susceptible group (40.8%) and 201 (45.3%) in the very susceptible group. Thirty-three (7.4%) ecotypes were more resistant and 29 (6.5%) ecotypes had resistance on the level of the most resistant control variety Ottos (score of resistance 5.3). Eight ecotypes (1.8%) with the highest level of resistance (score 7 or higher) were identi®ed as especially promising sources of rust resistance. One ecotype (141858) showed reaction type 9 in both years and another one (141903) showed reaction type 9 in one year and reaction type 8 in another year (mean 8.5). Six ecotypes were scored on average 7 or 7.5. For 17 di€erent habitats from which the tested ecotypes were collected only those ecotypes originating from 10 habitats (meadow, peat meadow, forest meadow, pasture, ®eld, lakeside, waterside, ditch, roadside and gravel pit) showed high levels of resist- ance to rust. The value of newly identi®ed resistant ecotypes for control of rusts on Kentucky bluegrass is discussed.