Abstract
The authors developed new inoculation methods and evaluated approximately five thousand barley verieties for screening resistant varieti.es to Fusarium head blight or scab. For the first mass selection, the 'cut-spike' inoculation method was applied: At the time of flowering, spikes were taken off frorn the plants at the second internodes, arranged in pans with overflowing water and were inoculated with an ascospore suspension of Gibberella zeae. Spikes were kept at 25°C and at 100% humidity for two days after inoculation, and then transferred to a growth chamber where the temperature and humidity were controlled at 23-13°C (with a sine curve) and about 95%, respectively. Illumination was 5, 000-10, 000 lux during 14 hours a day. Eight days after inoculation, the reaction of the varieties to the causal fungus was scored from 0 to 8 according to the infected spikelet percentage (Tables 1 and 2). Varietal differences in the scores were highly siguificant, indicating the efficiency of the inoculation method (Table 4). Varieties with the score of less than 4 were resistant and those with more than 4 were susceptible in the field conditions (Table 5).
