DIFFERENCES IN LEVEL OF TOLERANCE TO CEREAL APHIDS IN 5 WINTER-WHEAT CULTIVARS

Five winter wheat cultivars (Hana, Regina, Sparta, Viginta and Zdar) w ere analyzed for their level of tolerance to the cereal aphids Metopol ophium dirhodum, Rhopalosiphum padi and Sitobion avenae under greenhou se conditions. The individual aphid species differed in their effect o n seed weight of wheat cultivars. A joint evaluation of all cultivars proved the losses in seed weight caused by all aphid species to correl ate positively with aphid densities and dry mass production per tiller (ear). Comparison of losses in seed weight of individual cultivars re lated to 1 mg of aphid dry mass production showed differences in the l evel of tolerance (sensitivity) to aphid feeding among the cultivars t ested. A high level of tolerance to M. dirhodum and R. padi was found in Regina and Zdar and to S. avenae in Hana. Sparta was the only sensi tive (intolerant) cultivar to all aphid species. Tolerance as a compon ent of plant resistance to cereal aphids is discussed.