What is seed coat mottling?
Sometimes, seeds infected by SMV may have seed coat mottling, a dark discoloration from the hilum (the scar marking the attachment point of the ovule), and this symptom may be used to identify SMV. However, coat mottling should not be used as a main symptom for SMV identification because of inconsistency between coat mottling and SMV infections. An Iowa State University study shows that in some varieties, such as Williams, seed coat mottling is highly associated with SMV infection, but not for other varieties such as Corsoy. Some SMV-infected seeds do not have coat mottling symptoms. Physiological factors also can cause seed coat mottling. I have observed seed mottling from pods injured by insects, such as bean leaf beetles. The most reliable way to determine if seeds are infested with SMV is to send seed to the ISU Seed Science Center for a test at a reasonable price. The phone number of the Seed Science Center is 515-294-6821. What is the problem? A common concern from producers is t
