Abstract

This study was conducted to detect fungi associated with seed rot and seedling death of tomato in tomato growing areas in Najaf, where pathogenic fungi were isolated and purified from ten main tomato fields in the study area. The detection and isolation results showed that seed rot and seedling death of tomato in the detection areas were caused by the two pathogenic fungi Rhizoctonia solani and Fusarium oxysporum. The results showed a clear variation between the pathogenic isolates in terms of color and shape of the fungal hyphae, density and growth rate, in addition to a difference in the virulence of the fungus in causing the disease. Although R. solani showed faster growth on PDA medium, F. oxysporum showed higher pathogenicity and always resulted in higher rates of tomato seedling death. The molecular diagnosis and sequencing results showed that the isolated R. solani was completely identical to that those isolated and diagnosed in Pakistan (PQ304388.1), Turkey (PP339772.1), and Serbia (OP546633.1). Similarly, the NCBI data base showed that F. oxysporum in this study had a 100% similarity to those identified in China (PQ482025.1), USA (PQ443573.1), and India (PQ387094.1).