Evaluation of Partial Resistance Components in some Promising Wheat Lines of Cold Climate Zone to Yellow Rust Disease in Field Condition in Ardebil, Iran

A set of 21 bread wheat lines of cold climate zone of Iran, along with two susceptible check cultivars were studied to determine their partial resistance to yellow rust. Different components of partial resistance including coefficient of infection (CI), final rust severity (FRS), relative area under disease progress curve (rAUDPC), and apparent infection rate (r) were evaluated at both seedling and adult plant stages under field conditions. Lines C-91-9, C-91-20 and susceptible checks had the highest values of rAUDPC, FRS, CI, r, pustule density and pustule size. Lines C-91-1, C-91-7, C-91-8, C-91-15 and C-91-18 were resistant or had low infection at both seedling and adult plant stages. Lines C-91-12 and C-91-21 were susceptible at seedling stage, but showed resistance reaction or low infection at adult plant stage. These lines seem to have slow rusting (partial) resistance. Lines C-91-13 and C-91-14 were moderately resistant at seedling and resistant at adult plant stage, while lines C-91-3, C-91-4, C-91-16 and C-91-17 had moderate level of partial resistance and C-91-2, C-91-5, C-91-6, C-91-9, C-91-10, C-91-11, C-91-19 and C-91-20 were susceptible. Positive and significant correlations were observed between FRS and CI and also between rAUDPC and apparent infection rate. The highest coefficient of correlation (r) was observed between FRS with CI (r = 0.99).