FACTORS CONDITIONING DOMINANCE OF RACE 276 OF PUCCINIA-CORONATA-AVENAE ON AVENA-STERILIS POPULATIONS IN ISRAEL

Isolates of Puccinia coronata avenae races 276 and 263 were collected from Avena sterilis in different ecological locations. Components of pathogen fitness of the isolates were compared in different temperatures in the greenhouse and in the field. The results obtained may help provide an explanation for factors that contribute to the dominance of race 276 over race 263. There results were found countrywide and over many years, despite the fact that race 263 had a wider host range in seedling populations of its main host, A. sterilis L., in greenhouse trials. The study revealed that isolates of race 276 showed advantages under different environmental conditions in producing higher yields of urediospores with preferential viability. Telial formation occurs later, and the period of urediospore productivity is thus prolonged.