Impact of UV-B radiation on aspects of germination and epidemiological components of three major physiological races of Puccinia striiformis f. sp. tritici

Effects of UV-B radiation intensity and timing on epidemiological components of wheat stripe rust

“…When healthy wheat seedlings were inoculated using urediospores collected from wheat leaves irradiated with UV-B only post inoculation, the incubation period was prolonged and the infection efficiency, sporulation quantity, and disease index decreased. Post-inoculation UV-B radiation reduced infectivity of Pst, which may be related to reduction of Pst vitality due to UV-B radiation (Jing et al 1993;Cheng et al 2014). When healthy wheat seedlings were inoculated using the urediospores collected from the wheat leaves irradiated both pre-and post-inoculation, Pst pathogenicity was influenced and wheat stripe rust was reduced.…”

“…Mingxian 169, a wheat cultivar susceptible to all known physiological races of Pst in China, was grown as the experimental host material. Using methods previously described by Cheng et al (2014), urediospores of CYR33 were multiplied on wheat seedlings grown in a climate-controlled growth chamber at a temperature of 11-13°C and 60-70% relative humidity under 12 h light at 10 000 lux per day. UV-B radiation was performed with 36 W UV313 lamps (Beijing Lighting Research Institute, Beijing, China) in the growth chamber described above.…”

“…The epidemiological components, including incubation period, infection efficiency, sporulation quantity and disease index, were investigated using methods previously described by Cheng et al (2014). To assess the incubation period, after chlorotic spots appeared on the inoculated wheat leaves, leaves were observed daily or after UV-B radiation at 16:00 every day, and the day on which the first uredinium ruptured was recorded.…”

“…The total sporulation quantity under certain UV-B intensity or the control in each treatment was calculated by summing the average sporulation quantities across the entire sporulation period. Plants were surveyed for disease incidence and severity every 5 days post symptom appearance, and the disease index was calculated, all according to Cheng et al (2014). In this study, all statistical analyses of the significant differences at the 0.05 level were performed.…”

“…Jing et al (1993) investigated the effects of UV radiation on Pst using artificial inoculation of UV-irradiated urediospores of two Chinese physiological races of Pst (CYR19 and CYR29) on the highly susceptible wheat cultivar Huixianhong, and found that UV radiation could severely reduce the germinability of the urediospores and weaken the pathogenicity of Pst. Cheng et al (2014) looked at effects of UV-B radiation on epidemiological components of wheat stripe rust caused by three physiological races of Pst (CYR31, CYR32 and CYR33). The results demonstrated that UV-B radiation prolonged the incubation period, reduced the germination rate and infection efficiency of each physiological race, and caused the decreases in the lesion expansion rate, sporulation quantity and area under disease progress curve (AUDPC).…”