تشخيص عزلات الفطر Fusarium oxysporum f. sp. lycopersici وتقييم امراضيتها تجاه الاصناف التفريقية لنبات الطماطه

Abstract

This experiment was conducted under glasshouse and laboratory conditions during spring season, 2013 to identify the isolates and evaluate the pathogenicity of the causal agents of tomato wilt disease using morphological and microscopy characteristics together with three differential varieties of tomato plant coded (2013 – 1, 2013 – 2 and 2013 – 3) that certified by seed production company (BHN) in California, USA. The isolates were collected from (Olla) c.v. of tomato fields infected with vesicular wilt disease from 3 provinces Karbala , Najaf and Babylon in the middle of Iraq.Ten isolates were identified, and distributed as following: (F4, F6, F13 and F17) from Babylon, (F2 and F8) from Karbala and (F1, F9, F22 and F20) from Najaf. Isolates F2, F6, F8, F17 and F20 were identified as Fusarium oxysporum f. sp. lycopersici whereas F1, F9, F22 were recognized to be from anther forma specials of this fungus while F20, F13 are do not belong to the another species of F. oxysporum. All isolates were virulence except isolates F17 and F22 that both of them are avirulence. Fol isolates were revealed different levels of growth in PDA medium. The results showed that isolates F 6 and F17 can classified as race 1 of Fol , while the F2 , F8 and F4 isolates were identified as race 3. in Karbala province while the isolates. This finding is related to the race 3 is the first record in Iraq.