Rust — Hybrid Ryegrass

The causal agent of crown rust, Puccinia coronata, infects hybrid ryegrass, manifesting as characteristic uredinia with urediniospores on the surface of leaf blades. Pathogen development is most often observed in the second half of the growing season and during the autumn period, especially in the presence of plant stress factors or insufficient mineral nutrition.

In breeding practice and variety testing, the degree of crop infection is assessed on a nine-point scale, where 1 point corresponds to an immune or highly resistant state, and 9 points to high susceptibility with numerous pustules. Due to the lack of specific resistance genes, ryegrass breeding is aimed at achieving field resistance of populations, which is recorded in variety characteristics as a quantitative indicator.