RESPONSE OF DIFFERENT GENOTYPES OF BORO RICE TO FOLIAR APPLICATION OF MICRONUTRIENTS UNDER SALINITY STRESS

Abstract

The field experiment was conducted at net house of the department of agronomy, Sher-e-Bangla Agricultural University during the period from November, 2019 to March, 2020 to evaluate the effect of foliar application of micronutrients for increasing salinity tolerance in rice plants. The experiment consisted of three factors. The factors were: factor A: Salinity level (2): S₁ = Control (No saline water) and S₂ = 150 mM NaCl; factor B: Micronutrients (4): M₁ = Control (No micronutrients), M₂ = Zinc (0.5%), M₃ = Boron (0.5%) and M₄ = Zinc (0.5%) + Boron (0.5%); factor C: Variety (5): V₁ = BINA dhan10, V₂ = BINA dhan8, V₃ = BRRI dhan29, V₄ = BRRI dhan47 and V₅ = BRRI dhan67. The experiment was laid out in a RCBD factorial design with three (3) replications. Results showed that the salinity stress-imposed plants S₂ (150 mM NaCl) were out-yielded by producing 58.23% lower grain yield than control plants S₁ (No saline water). The treatment S₂ (150 mM NaCl) also showed the shortest plant at harvest (78.69 cm), lowest tillers hill −1 (6.27), shortest leaf at harvest (28.50 cm), narrowest leaf at harvest (1.45 cm), shortest panicle length (18.56 cm), lowest filled grains panicle⁻¹ (52.04), highest unfilled grains panicle⁻¹ (17.07), maximum weight of 1000-grains (17.86 g), straw yield (21.69 g hill ), biological yield (42.40 g hill −1 ) and harvest index (48.84%) in compare to control or no salinity stress-imposed plants. Significant differences existed among different levels of micronutrient applications with respect to yield and yield attributing parameters. A yield advantages of 5.28 g, 5.31 g and 10.94 g hill −1 over M₁ (No micronutrients), M₃

[B (0.5%)] and M₂ [Zn (0.5%)] applied pot, respectively was found which was possibly aided by taller plant (86.24 cm), higher tillers hill −1 (7.94), longer panicle (22.21 cm), maximum filled grains panicle⁻¹ (67.79), lowest unfilled grains panicle⁻¹ (12.19), highest weight of 1000-grains (20.93 g), straw yield (26.07 g hill −1 ), biological yield (56.31 g hill −1 ) and harvest index (53.70%) in the M₄ [Zn + B (0.5%)] treatment. On the other hand, treatment M₃

[B (0.5%)] gave similar results to M₄

treatment in some parameters like—plant height, tillers number, leaf length, unfilled grains panicle⁻¹, panicle length, weight of 1000-grains, straw yield, biological yield and harvest index. M₃

[B (0.5%)] or M₄ [Zn + B (0.5%)] treatment seemed promising in mitigating salinity stress in rice field compared to individual application of zinc or boron. Results also showed that V₅ (BRRI dhan67) exhibited its superiority to other tested variety BINA dhan10, BINA dhan8 and BRRI dhan29 in terms of seed yield, the former out-yielded over V₁ (BINA dhan10) by 13.34%, V₂ (BINA dhan8) by 1.27% and V₃ (BRRI dhan29) by 1.20 % higher yield. Interaction of S₁V₂M₁ (No saline water × BINA dhan8 × No micronutrients) performed better in most of the studied parameters. The S₁V₂M₁ treatment combination also showed better performance in terms of grain yield. Taking together these results suggested that B (0.5%) or Zinc (0.5%) + Boron (0.5%) combined application along with variety BRRI dhan29 and BRRI dhan67 showed better performance under salinity stress condition.