Random cuttings of each plant variety are grafted to an "Ipomoea Setosa," used for indexing.  The Setosa is a very fragile plant which has to be grown in sealed cages for protection from insects which could be fatal to it.  It is a type of Brazilian Morning Glory which is susceptible to nearly everything and readily shows virus and disease symptoms. Setosa looks like a hairy version of the common sweetpotato.

Sweetpotato cuttings being grafted to the Setosa for indexing. 

A successful graft of the O'Henry variety of sweetpotato being logged and read for future verification.

A neatly knit graft showing healthy, green leaves having no marks or streaks in the leaves of the Setosa below the graft line, indicates a virus and disease free plant.  Meristemming was successful here. This plant will become a mother plant to be propagated by the tens of  thousands.