Enhancing the performance of transplanted coarse rice by seed priming

Raising the rice seedlings in the nursery and its transplantation into the flooded fields is principal method of rice cultivation in the world. Traditional nursery raising method in Pakistan is tedious and produces week seedlings, which reduces the final yield due to high mortality. The potential of seed priming to improve the nursery seedlings and thus the transplanted rice was evaluated in the present study. Seed priming tools employed during the investigation included traditional soaking (pre-germination), hydropriming for 48 h, osmohardening (KCl or CaCl₂) (ψs-1.25 MPa) for 24 h (1 cycle), ascorbate priming (with 10 ppm ascorbate) for 48 h or seed hardening for 24 h. Priming improved nursery seedling vigor and resulted in improved growth, yield and quality of transplanted rice. Osmohardening (KCl) consequently resulted in the best performance, followed by osmohardening (CaCl ₂)_, hardening and ascorbate priming. Osmohardening (KCl) produced 4.28 t ha^-1 (vs. 3.51 t ha^-1 from untreated control) kernel yield, 10.27 t ha^-1 (vs. 9.34 t ha^-1 from untreated control) straw yield and 29.41% (vs. 27.31% from untreated control) harvest index. The improved yield was attributed to increase in number of fertile tillers.