Dormancy-breaking treatments in two potential forage crop legumes from the semi-arid rangelands of South Africa

Abstract

Native forages have been proposed as a plausible alternative to the use of exotic forage germplasm due to their adaptation to the surrounding bioclimatic and edaphic conditions, and the reduced risk of becoming weedy or invasive. Calobota sericea and Lessertia frutescens are two perennial legume species from the semi-arid rangelands of Namaqualand and are currently under investigation as fodder crops for use within these agro-ecosystems. These species display physical seed dormancy, and therefore, we aimed to investigate methods to break their dormancy to ensure fast and uniform seed germination and establishment. After collection, C. sericea and L. frutescens seeds were subjected to three dormancy breaking treatments, namely, mechanical scarification, boiling the seeds for 5min, and placing the seeds in boiled water and leaving them until the water has cooled to room temperature. The seeds were thereafter germinated in petri-dishes. Mechanical scarification was the most effective method to break dormancy, and once the dormancy was removed, germination commenced rapidly. However, further research is needed to determine more efficient means to scarifying larger quantities of seeds.