Uredospore density of Puccinia triticina races on infection efficiency in wheat

Abstract

Wheat leaf rust caused by the fungus Puccinia triticina may lead to damage of up to 62%. This study aimed to test the effect of different uredospore concentrations on the infectious process of four physiological races. The races MFJ-MN, MFT-MT 4002 S, TPT-HT and TDP-HT were inoculated, when the first leaf was expanded in the seedling stage, on cultivars Ônix, Abalone, Morocco and Quartzo, respectively. The tested concentrations were 0.0; 5 x 103; 10 x 103; 20 x 103 and 40 x 103 uredospores/mL mineral oil (Soltrol). After inoculation, seedlings were kept in a growth chamber at 20°C ± 2, near 100% humidity, in the dark, for 20 hours. Fifteen days after inoculation, the density of uredia/leaf was evaluated. The concentration of 40 x 103 uredospores/mL resulted in a disease intensity that allows safe differentiation between susceptible and resistant cultivars in the seedling stage, without causing leaf senescence due to high uredinium density.

Quantificação de parâmetros monocíclicos da antracnose (>i<Colletotrichum lindemuthianum>/i<) e da mancha angular (>i<Phaeoisariopsis griseola>/i<) do feijoeiro

“…A quantificação dos parâmetros período de incubação e período latente tem sido feita, de uma maneira prática, considerando-se o período de tempo entre a inoculação e o aparecimento de 50% dos sintomas ou lesões esporulantes, respectivamente (Parlevliet, 1975;Mehta & Igarashi, 1979;Mendes & Bergamin Filho, 1986).…”