I. Acid treatment and mechanical scarification

Abstract Only about 30% of the Centrosema pubescens (centro) seed examined germinated under favourable conditions of moisture and temperature. Germination percentage increased to more than 80% after seed treatment with concentrated sulphuric acid or by mechanical scarification. Seeds could be treated with acid for up to 20 min without impairing germination capacity. Maximum normal seedlings with scarification were recorded when seeds were scarified at 22.5 psi or 25.0 psi for 5 min. As the pressure or duration of scarification or the duration of acid treatment was increased, the number of abnormal seedlings also increased. Furthermore, acid‐treated or scarified seeds produced more abnormal seedlings than untreated seeds.