M Harati - Seed and plant registration and certification research institute- Shahrood-Iran
S Osroosh - Seed and plant registration and certification research institute - Karaj-Iran
L Zare - Seed and plant registration and certification research institute - Karaj-Iran
S Hashemi Fesharaki - Seed and plant registration and certification research institute - Karaj-Iran

In order of importance of seed and its role in spread and transmission of threatening pathogens,seed health tests are unavoidable. When inoculums borne internally in seeds, the transmissionpotential of the infected seed which is operative and can be defined as the number of seeds in asample capable of transmitting infection. Loose smut of barley is one of the most important seedborne diseases that cause heavy damage. In the study ١٠ seed samples of Reyhan ٠٣, Kavir andNosrat varieties from Semnan and Damghan seed production fields collected and base on ISTArules, embryo test was done. Average seed infection in certified category was recorded as ٠.٤,١.٢and ٠.٤% respectively for Nosrat, Kavir and Reyhan ٠٣. Average infection percentage of certifiedseed category in Semnan province was ٠.٦ with range of ٠ – ١.٦%. This amount of infection ascompare to study carried in the year ١٣٨٨, recorded as ١.٦% showed ٣٧.٥% reduction of infection.But to reach to barley national seed standard, is necessary to observe phytosanitary measures suchas selection of healthy seed, seed treatment with chemical poisons, isolation distance and etc.

seed, test, infection, varieties, loose smut