Morphological Variability in Melampsora ciliata - the Incitant of Poplar Leaf Rust

Variation in the dimensions of urediniospores of Melampsora ciliata harvested from different Poplar species grown under different environmental conditions has been observed in the present investigations. Smallest urediniospores (20.88 x 15.43 µm) produced on P. ciliata were recorded at Rahla (Zone III) while largest (36.30 x 19.97 µm) were recorded at Raison (Zone II). Urediniospores produced on P. deltoides and P. nigra were smaller in size at Nauni and Raison (Zone II), while larger spores on these species were recorded at Shoghi and Tapri (Zone III). Spores produced in pustules of P. alba at Spillo were smaller as compared to those produced at Reckong Peo. Irrespective of the host genotype and climatic zone, smallest urediniospores were produced on P. alba.