Collections of Tilletia species are commonly maintained in the form of
sori harvested from smutted heads. This has been a convenient and eff
ective storage method because teliospores enclosed in a sorus remain v
iable for over 20 years. However, mycelial cultures derived from germi
nated teliospores are genetically mixed because of meiotic segregation
among sporidia. For the purposes of genetic analysis and establishing
strain identity, it is necessary to maintain haploid sporidial cultur
es that can be readily retrieved for manipulations. We found that spor
idial cultures of Tilletia tritici and Tilletia controversa can be pre
served for at least 1 year by suspending a mixture of mycelia and spor
idia in 15% glycerol and storing at -70 degrees C. Approximately 80% o
f the stored cultures were viable after 12 months in storage. Five out
of nine monosporidial cultures of T. tritici and T. controversa teste
d retained their sexual fertility in interspecific crosses. The glycer
ol storage method has advantages over serial transfer in the maintenan
ce of monosporidial cultures by reducing the accumulation of somatic m
utations; however, the technique should be used cautiously until great
er infectivity of stored cultures is demonstrated.