حساسية بعض أصناف الذرة الصفراء لمرض تعفن الجذور المتسبب عن الفطر Rhizoctonia solani Kühn

الملخص EN

Abstract This study was aimed to isolate and diagnosis the causal agent of the root rot diseases of corn ( Zea mays L.) from infected plants in the fields of Babylon province and test the sensitivity of some varieties for Rhizoctonia solani pathogen.

The results showed the disease appeared in all the samples with the disease incidence 20 – 100%.

It was isolated and identified six isolates of R.

solani fungus These isolates showed high pathogenicity and prevent the germination of radish seeds compared to control which was 93.33% .

the results of sensitivity of 15 varieties of corn used in Iraq were that all varieties was susceptible to infection by R.

solani, the disease incidence was 20-80% and severity 4-64% .

Sun-6, 5683, Fajer -1 and Drc24 varieties was most resistant and tolerant for the infection and have low disease incidence 20% and severity 5.33-12.0%, the plant height was 23.33-30.60 cm , fresh weight 2.70-3.40g and dry weight was 0.60- 0.92g.

whereas, the high disease incidence and severity appeared in the Bohoth 106, W.F.C 24 and 5012 varieties which was 100% and 84-93.33% respectively.

this effect and reduced the corn growth parameters.

This results showed for the first time sensitive of corn varieties used in Iraq to infection by R.

solani causing agent of corn root rot disease.