Effect of hydro-, halo- and osmopriming on seed germination and seedling performance of Psophocarpus tetragonolobus (L.) DC. (winged bean)

Abstract

Psophocarpus tetragonolobus (L.) DC. (Fam. Fabaceae) popularly known as winged bean is an underutilised legume. One of the major problems in achieving rapid propagation of winged bean is the very low rate of germination of the stored seeds rather than seed dormancy. Different priming methods were tried to improve the winged bean seed germination. To find out the seed germinability of winged bean, conventional hydropriming method was used. For enhancing germination percentage and seedling vigour, halo (NaCl)- and osmopriming (mannitol and PEG 6000) methods were utilised. Physiological and biochemical analyses were undertaken to elucidate the priming effect on seedlings. Hydropriming treatment did not show improved germination up to 80% and overall performance of seedling was not satisfactory. However, Ha2 (125 mM for 48 h) improved the germination percentage up to 82.49%. In the present study, both the osmopriming treatments (mannitol and PEG) revealed that seed germination increases by increasing concentration, but after certain limits germination percentage declined. PEG solution with osmotic potential, OP6 (− 1.0 MPa for 24 h) treatment and mannitol solution of osmotic potential OM10 (− 1.5 MPa for 36 h) treatment showed best results and is considered the best priming treatment for the tested lot of seeds. In this experimental condition, mannitol gives better germination and seedling growth compared to PEG 6000. It was concluded that 125 mM for 48 h was the best priming treatment to enhance the germinability, antioxidant enzymes and biochemical activities in P. tetragonolobus.