Identification of Fusarium Oxysporum F.SP. Niveum Races Causing Vascular Wilt Disease in Watermelon Plants in Western Iraq

This study aimed to identify and classify races of Fusarium oxysporum f.sp. niveum, the causal agent of Fusarium wilt in watermelon, using precise molecular methods. Nine fungal isolates were collected from different agricultural regions in Iraq and identified using Polymerase Chain Reaction (PCR) techniques with specialized primers targeting specific regions of the fungal DNA. After molecular confirmation, the pathogenicity of these isolates was tested on five hybrids of the Charleston Gray watermelon cultivar in a laboratory experiment, helping to assess the pathogenic effects of the isolates. The results showed significant variation in the pathogenic abilities of the isolates, with Race 3 being the most aggressive, displaying infection rates ranging from 80-100% and infection severity between 76.6-96.5%. This study highlights the importance of using molecular techniques for accurately and rapidly identifying pathogenic races, which can aid in developing effective disease management strategies and reducing agricultural crop losses.