Tz test of seeds is done for testing the

TZ is Tetrazolim Chloride seed test is a rapid germination test, the result is out within 24 hours. It is a chemical test used to determine seed viability.
TZ test is used to detect seed weaknesses before they become evident in germination tests and it also provides timely guidance in quality control programs.
But TZ test requires specialized training and experience and is more laborious and tedious to perform than a germination test. Moreover, TZ tests do not reflect dormancy as well as fungal or chemical damage.