Overcoming the hard seededness in Centrosema pubescens seeds

Abstract

In Centrosema pubescens, hard seed coat is the main problem impeding the germination by preventing water and gaseous exchange in the seed. Therefore, to improve the germination and other seed quality parameters, three different types of dormancy breaking treatments were employed. Accordingly physical dormancy breaking was done with hot water and hot air, mechanical scarification with sandpaper and chemical treatment with GA3 , KNO3 , H2 SO4 and Thiourea. Results obtained during the study revealed that control seeds showed very low germination (10.0%) and hot water treatment increased germination (66.67%). The complete and sharp increase in germination achieved by physical scarification with hot water shows that the dormancy originated by seed coat (hard seededness) whereas, acid scarification resulted in lowest germination (2.67%) due to charring. The hot water treated seeds performed better over other treatments under storage conditions with regards to higher and increased seed germination, reduced hard seeds percentage seedling vigour index. Whereas the control treatment exhibited large scale hard seed coat dormancy even after 12 months of storage (58.0%).