An assessment of the transmission rate of four pospiviroid species through tomato seeds

Greenhouse experiments were conducted to investigate the importance of tomato seeds as a route of pospiviroid dissemination. More than 7000 seeds were collected from tomato plants mechanically inoculated with Tomato apical stunt viroid , Citrus exocortis viroid , Columnea latent viroid and Potato spindle tuber viroid . Fruits and part of the seeds were found to be 100 % infected by the inoculated pospiviroid by means of RT-PCR testing. Much of the rest of the seeds were sown and produced about 4700 seedlings. None of the seedlings were found positive for the respective pospiviroid. This shows that pospiviroid seed transmission in tomato is very rare.