Evaluation of resistance to the ordinary strain of Potato Virus Y (PVYO) in four potato cultivars under greenhouse condition

Potato virus Y (PVY) is the type species of the genus Potyvirus in Potyviridae، and is one of the most important potato infecting viruses which can cause severe crop loss in epidemics. This damage and reduction of yield depends on several factors including potato cultivar، time of infection and virus strain. Currently all tobacco and potato fields are sensitive to PVY and its infection is widespread in many potato fields in Golestan province. Use of resistant varieties is considered as the most effective and economic، and safest method to reduce damages of plant viruses. This study was performed to determine the reaction against PVYO of four prevalentpotato varieties cultivated in the potato fields of Golestan، including Banba، Boren، Marla and Satina، and to identify possible sources of resistance. Eight leaved plants from each cultivar were inoculated mechanically with extract of tobacco leaves infected by PVYO. Plants were kept in greenhouse and symptoms evaluated for four weeks. Statistical analysis was performed using the recorded ratings of the symptoms. Inoculated plants were tested by DAS-ELISA. PVY symptoms، with different severities، were observed in all varieties. Satina was the only variety which its symptom ratings was significantly lower than the total mean، but the maximum titer of virus was observed in DAS-ELISA experiments for Boren variety.