A viability test for seeds of Townsville stylo using thiourea

Abstract

Thiourea stimulates the germination of dormant Townsville sty10 (Stylosanthes humilis) seed. The viability of seed lots may thus be assessed immediately after harvest by extracting seeds from pods, scarifying them and incubating at 30°C in 0.1 M or 0.2 M thiourea for 1-3 days and counting those with emerged radicles. This method is not proposed as a germination test because the seedlings so produced may be abnormal, but evidence to validate it for the purpose of establishing viability is given. Sensitivity to thiourea varies with variety and seed age, but not in any systematic fashion that would permit prediction of duration of dormancy.