Seed invigoration by osmohardening in coarse and fine rice

The effects of seed hardening treatments using different salt solutions on the germination, emergence and seedling vigor in coarse and fine rice were investigated in a laboratory trial. Seeds were hardened both using tap water (referred to as hardening) and with CaCl₂, KNO₃, KCl, NaCl solution (osmohardening) in such way that osmotic potential of all the solutions was - 1.25 MPa. In both coarse and fine rice, osmohardening with CaCl₂ performed the best compared with all other treatments as indicated by lower values of time to start germination, MGT, T₅₀ and MET and higher values of final germination and emergence, speed and energy of germination, root and shoot length and seedling fresh and dry weight. Simple hardening and osmo-hardening with KCl were next best treatments.