University of Guilan Iranian Journal of Seed Sciences and Research 2476-3780 11 2 2024 06 21 Evaluation of the transmission rate and effect of loose smut disease on the some growth indicators of barley seedlings in the field Evaluation of the transmission rate and effect of loose smut disease on the some growth indicators of barley seedlings in the field 1 16 8660 10.22124/jms.2024.8660 FA Nima Khaledi Research Assistant professor, Seed and Plant Certification and Registration Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran Leila Zare Researcher, Seed and Plant Certification and Registration Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran Saman Sheidaei Research Assistant professor, Seed and Plant Certification and Registration Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran Journal Article 2024 05 06 Quick and accurate diagnosis of pathogenic agents associated with seeds is necessary for the prevention and control of seed-borne diseases. Loose smut disease is one of the most important seed-borne fungal diseases of barley throughout world, which causes a decrease in crop yield. The aim of this study was to compare different methods of the detection and diagnosis of the loose smut disease agents in seed samples, transmission rate to the next generation and to evaluate the effect of seeds infection on the growth indicators of seedlings in the field. In order to detect infection in seed samples and identify the fungus that causes loose smut disease, from different cultivars of barley produced in the some fields of Isfahan, Khuzestan, North Khorasan, South Khorasan, Alborz and Hamedan provinces were sampled according to the International Seed Testing Association rules (ISTA). The results of comparison of diagnosis methods showed that the modified embryo test compared to ICARDA method can be considered as a more reliable method for detect smut infection in seed samples based on sensitivity, time required, simplicity and cost. The results revealed that there is a strong positive correlation between level of seed infection detected in the modified embryo test and the disease incidence in the field. Infected seeds has significantly affected the growth indicators of seedlings in the field while increasing the mean emergence time, the causes decreasing the field emergence rate and final emergence percentage in field. The findings of this research provide new insights into the effect of seed infection on the growth indicators of seedlings and transmission rate of disease in the field, which can be used for the revision of the national standard for barley seed and the effective management of this disease. Quick and accurate diagnosis of pathogenic agents associated with seeds is necessary for the prevention and control of seed-borne diseases. Loose smut disease is one of the most important seed-borne fungal diseases of barley throughout world, which causes a decrease in crop yield. The aim of this study was to compare different methods of the detection and diagnosis of the loose smut disease agents in seed samples, transmission rate to the next generation and to evaluate the effect of seeds infection on the growth indicators of seedlings in the field. In order to detect infection in seed samples and identify the fungus that causes loose smut disease, from different cultivars of barley produced in the some fields of Isfahan, Khuzestan, North Khorasan, South Khorasan, Alborz and Hamedan provinces were sampled according to the International Seed Testing Association rules (ISTA). The results of comparison of diagnosis methods showed that the modified embryo test compared to ICARDA method can be considered as a more reliable method for detect smut infection in seed samples based on sensitivity, time required, simplicity and cost. The results revealed that there is a strong positive correlation between level of seed infection detected in the modified embryo test and the disease incidence in the field. Infected seeds has significantly affected the growth indicators of seedlings in the field while increasing the mean emergence time, the causes decreasing the field emergence rate and final emergence percentage in field. The findings of this research provide new insights into the effect of seed infection on the growth indicators of seedlings and transmission rate of disease in the field, which can be used for the revision of the national standard for barley seed and the effective management of this disease. https://jms.guilan.ac.ir/article_8660_232d82e03a7e6ebe078048e602157cbd.pdf