In this study, variability in pathogenicity among Fusarium graminearum isolates from different locations in Ohio was determined. The most virulent isolates from these locations were chosen and used in segregation studies to evaluate the resistance of some resistant by resistant winter wheat crosses to Fusarium head scab. | Turk J Agric For 25 (2001) 37-43 © TÜB‹TAK Screening of Wheat Varieties for Resistance to Head Scab Caused by Fusarium graminearum Schwabe Sibel DERV‹fi Mustafa Kemal Üniversitesi, Ziraat Fakültesi, Bitki Koruma Bölümü, 31043 Hatay - TÜRK‹YE Received: Abstract : In this study, variability in pathogenicity among Fusarium graminearum isolates from different locations in Ohio was determined. The most virulent isolates from these locations were chosen and used in segregation studies to evaluate the resistance of some resistant by resistant winter wheat crosses to Fusarium head scab. Differences in pathogenicity levels were significant among isolates even from the same location. Several generalizations can be made about the segregating generations in this study. The results indicated that Ning 7840 carries multiple genes for resistance. In addition, we found that Freedom and Ning 7840 have at least one resistance gene different. Although the level of resistance observed in the resistant by resistant cross appear to be adequate to protect the cultivar against head scab damage, higher levels of resistance would be useful in the future. As more resistant cultivars are identified, some popular but Fusarium scab suscebtible cultivars, may be replaced. Key Words: wheat varieties, Fusarium graminearum, head scab, resistance Fusarium graminearum Schwabe’un Neden Oldu¤u Baflak Uyuzuna Karfl› Dayan›kl› Bu¤day Varyetelerinin Belirlenmesi Özet : Bu çal›flmada Ohio’da çeflitli bölgelerden elde edilen Fusarium graminearum Schwabe izolatlar›n›n patojenisiteleri aras›ndaki farkl›l›klar saptand›. Bu izolatlardan en virulent olanlar seçildi ve baz› dayan›kl› X dayan›kl› k›fll›k bu¤day varyetelerinin Fusarium baflak uyuzuna karfl› dayan›kl›l›klar›n› de¤erlendirmek için yap›lan segregasyon çal›flmalar›nda kullan›ld›. Patojenisite düzeylerinde, ayn› bölgeden al›nan izolatlar aras›nda bile önemli derecede farkl›l›klar görüldü. Bu çal›flmada segregasyon yapan hatlar hakk›nda .
