Seed Priming and Trichoderma Application: A Method for Improving Seedling Establishment and Yield of Dry Direct Seeded Boro (Winter) Rice in Bangladesh

Seedling mortality is the major barrier to optimum stand establishment in dry direct seeded boro (winter) rice. Two experiments were carried out at the Agronomy Field Laboratory, Bangladesh Agricultural University (BAU), Mymensingh, Bangladesh during January to June 2012 and 2013 to study the effect of seed priming, Trichoderma and fungicide application on seedling establishment and yield performance of dry direct seeded Boro rice. First experiment comprised three seed priming treatments, osmopriming with 3% ZnSO 4 solution, hydropriming and no priming. There were five treatment combinations of Trichoderma and fungicides. These were seed treatment with Trichoderma (T 1 ), spraying of rice seedling with sulphur fungicide (Thiovit) (T 2 ); propiconazole fungicide (Potent) (T 3 ), and combination of Thiovit and Potent (T 4 ) and a control treatment (T 5 ) where no fungicide or Trichoderma was applied. The treatment was applied at 20 days after sowing (DAS). In year 2013, the experiment comprised ten treatment combinations of Trichoderma and fungicides viz.seed treatment with Trichoderma (T 1 ), seed treatment with Trichoderma + spraying of Thiovit (T 2 ), seed treatment with Trichoderma + spraying of Potent (T 3 ), seed treatment with Trichoderma + spraying of Thiovit and Potent (T 4 ), spraying of Thiovit (T 5 ), spraying of Potent (T 6 ), seed treatment with Thiovit + spraying of Potent (T 7 ), seed treatment with Potent + spraying of Thiovit (T 8 ), spraying of mixture of Thiovit and Potent (T 9 ), and control (no fungicide or Trichoderma) (T 10 ). Both the experiments used Randomized Complete Block Design (RCBD) with three replications. Results showed that osmopriming gave higher number of seedling, length and dry matter of shoot and root and yield than hydropriming. All these attributes were highest with seed treatment by Trichoderma. Experiment 2 revealed that seed treatment with Trichoderma harzianum followed by spraying of Thiovit gave the highest yield of rice. The study concludes that sowing of seed after osmopriming with 3% ZnSO 4 and biopriming with Trichoderma and then application of sulphur fungicide at 20 days after sowing could be practiced for ensuring high seedling establishment and yield of rice under dry direct seeded system in boro season.