Impact of Allopurinol on Sunlfower Rust, Puccinia Helianthi.

A greenhouse study was conducted to study the effect of allopurinol on incompatible and compatible sunflower- Puccinia helianthi interactions. The use of allopurinol does not show the significant impact in incompatible sunflower- rust interactions, with only the size and number of lesions reduced. In contrast, allopurinol has significant impact on compatible sunflower – rust interactions. Use of any concentration of allopurinol either in drenching (20 – 200 µM) or through spray (100 – 400 µM) significantly changed the reaction type from compatible to the hypersensitive type reactions.