Uromyces viciae-fabae inoculation under controlled conditions

Background/Objective. The objective was to evaluate incubation and post incubation temperatures, inoculum concentrations, and maleic acid effect to develop an efficient and reproducible method for U. viciae-fabae inoculation in broad bean genotypes. Materials and methods. The evaluated factors were inoculum concentration, incubation and post-incubation temperatures, maleic acid concentration, and the inoculation method validation. The variables evaluated were type of infection, number of pustules, percentage of severity, pustule size, and latency period. Analysis of variance and comparison of means were performed using the Tukey test (p ≤ 0.05). Results. Incubation temperatures of 7 and 18 °C showed no significant differences. A urediniospore concentration of 3 x 106 showed significant differences in the number of pustules and severity. No symptoms were observed in the uncontrolled environment, averaging 24 °C. U. viciae-fabae was able to develop at controlled temperatures of 18 and 22 °C, and at uncontrolled temperatures averaging 20 °C. Conclusions. Efficient inoculation was achieved with a concentration of 3 × 106 urediniospores per mL-1 at an incubation and post-incubation temperature of 18 °C.