SEED INVIGORATION TECHNIQUES IMPROVE CROP ESTABLISHMENT AND PRODUCTIVITY IN DRY DIRECT SEEDED RICE

Abstract

Dry direct-seeded rice (DSR) is an alternative to conventional puddled transplanted rice because of its lower labour and water requirements. However, poor and non-uniform crop establishment under aerobic soil conditions remains a major constraint. A field experiment was conducted during the Kharif seasons of 2023 and 2024 at the Department of Rice, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, to evaluate different seed invigoration techniques for improving seedling vigour and productivity of dry DSR. The experiment was laid out in a randomized block design with seven treatments and three replications. The treatments comprised hydropriming, seed hardening with 1% potassium chloride (KCl), priming with 1% sodium chloride (NaCl) solution, seed treatment with CPB-1 (chitinolytic bacterium), Trichoderma asperellum, Bacillus subtilis and an untreated control. Seedling vigour index at 14 and 21 days after sowing (DAS), yield attributes, grain yield and straw yield were recorded. Priming with 1% NaCl recorded the highest seedling vigour index at 14 DAS (1094.32) and 21 DAS (2682.11), whereas CPB-1 recorded the highest productive tillers (332 m⁻²), panicle weight (2.75 g), grain yield (5406 kg ha⁻¹) and straw yield (7658 kg ha⁻¹). Although NaCl priming produced the highest early seedling vigour, CPB-1 resulted in superior yield performance, indicating that early vigour alone did not directly determine final productivity. The higher grain yield under CPB-1 was associated with improved productive tiller production and panicle weight. Overall, the results suggest that CPB-1 and seed hardening with 1% KCl have potential as practical seed invigoration techniques for improving crop establishment and productivity of dry DSR.