تقويم قابلية بعض أصناف القطن السورية للإصابة بمرض ذبول الفيرتيسليوم المتسبب عن الفطر Verticillium dahliae Kleb.

Abstract EN

Five Syrian cotton cultivars (Aleppo 33, Aleppo 90, Aleppo 188, Deir Ezzor 22, Raqqah 5) were evaluated for their susceptibility to V.

dahliae (isolate V11) infection in an outdoor pot experiment during the growing season 2010.

Results showed that all cultivars were damaged by V.

dahliae infection, to different degrees.

The average infection rate ranged between 62.5 and 100%.

Cultivar Deir Ezzor 22 was the most susceptible and cultivar Raqqah 5 was the least susceptible.

Two groups of varieties showed different levels of resistance.

The first group were Raqqah 5 and Aleppo 90 varieties that showed less susceptibility to infection.

The disease index of cross-section discoloration was 15 and 27.5, respectively, without significant difference with the moderately resistant variety Paymaster 792 (37.5).

By contrast, the second group which included the varieties Deir Ezzor 22, Aleppo 33, and Aleppo 118 demonstrated higher susceptibility with high degree of stem discoloration of 80, 65 and 57.5, respectively, with no significant difference with the susceptible variety Deltapine 16 (72.5).

Results of this study also showed similarity in the values of cross and longitudinal stem section discoloration indices when compared with leaf infection index.

Accordingly, disease evaluation can be made on both stems and leaves of infected plants.

Keywords: Local cultivars, Verticilium wilt, cotton, Syria.