82 4.4.2 Number of tillers hill⁻¹
4.5 Interaction effect of salinity and variety on growth, yield attributes, yield and harvest index of boro rice
4.5.1 Plant height
Plant height of rice plants ranged from 42.18 cm (S₂V₃) to 60.51 cm (S₁V₂) at 60 DAT and 54.19 cm (S₂V₃) to 70.37 cm (S₁V₂) at 90 DAT (Figure 12). Generally, it decreased in salinity stress condition irrespective of the varieties. Thus, interaction effect of salinity and variety showed significant impact on plant height of rice plants. Similar trend of plant height was observed at harvest stage where plant height ranged from 66.30 cm (S₂V₃) to 101.38 cm (S₁V₂). The tallest plant (101.38 cm) was seen under control condition (S₁V₂) and gradual decrease of plant height from 101.38 cm to 66.30 cm was observed with the imposition of salinity stress on all the rice varieties.
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Figure 12. Interaction effect of salinity and variety on plant height of boro rice. [S₁ and S₂ indicate control and 150 mM NaCl, respectively. V₁, V₂, V₃, V₄ and V₅ indicate BINA dhan10, BINA dhan8, BRRI dhan29, BRRI dhan47 and BRRI dhan67, respectively. Mean was calculated from three replicates for each treatment and significance of values were tested at p ≤ 0.05 applying LSD test]
4.5.2 Number of tillers hill⁻¹
Interaction effects of salinity stress and varieties of rice was significant on number of tillers hill⁻¹ of rice plants at 60 DAT, 90 DAT and at harvest (Figure 13). At 60 DAT, number of tillers hill⁻¹ ranged from 9.01 (S₂V₂) to 11.63 (S₁V₅) and at 90 DAT, number of tillers hill⁻¹ ranged from 5.53 (S₁V₄) to 9.03 (S₁V₁) where control condition had more tillers than saline condition. At harvest, tiller number ranged from 6.19 (S₂V₂) to 10.51 (S₁V₁) where control treatment combined with rice variety showed higher number of tillers in compare to varieties under salinity stress.
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Plant height (cm)
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Plant height at 60 DAT Plant height at 90 DAT
Plant height at harvest
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Figure 13. Interaction effect of salinity and variety on number of tillers hill⁻¹ of boro rice. [S₁ and S₂ indicate control and 150 mM NaCl, respectively. V₁, V₂, V₃, V₄ and V₅ indicate BINA dhan10, BINA dhan8, BRRI dhan29, BRRI dhan47 and BRRI dhan67, respectively. Mean was calculated from three replicates for each treatment and significance of values were tested at p ≤ 0.05 applying LSD test]
4.5.3 Leaf length and leaf breadth
Interaction of salinity and variety exerted significant impact on leaf length and leaf breadth of boro rice plants. Leaf length ranged from 26.78 cm (S₁V₃) to 37.62 cm (S₂V₁) (Figure 14). At harvest stage, the impact of salinity and variety interaction on leaf breadth was significant where leaf breadth ranged from 1.37 cm (S₂V₃) to 1.71 cm (S₂V₁) (Figure 15).
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Tillers hill⁻¹
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Tiller number at harvest
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Figure 14. Interaction effect of salinity and variety on leaf length of boro rice. [S₁ and S₂ indicate control and 150 mM NaCl, respectively. V₁, V₂, V₃, V₄ and V₅ indicate BINA dhan10, BINA dhan8, BRRI dhan29, BRRI dhan47 and BRRI dhan67, respectively. Mean was calculated from three replicates for each treatment and significance of values were tested at p ≤ 0.05 applying LSD test]
Figure 15. Interaction effect of salinity and variety on leaf breadth of boro rice. [S₁ and S₂ indicate control and 150 mM NaCl, respectively. V₁, V₂, V₃, V₄ and V₅ indicate BINA dhan10, BINA dhan8, BRRI dhan29, BRRI dhan47 and BRRI dhan67, respectively. Mean was calculated from three replicates for each treatment and significance of values were tested at p ≤ 0.05 applying LSD test]
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Leaf breadth (cm)
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4.5.4 Filled grains panicle⁻¹ and Unfilled grains panicle⁻¹
Filled grains panicle⁻¹ of boro rice ranged from 23.86 (S₂V₁) to 103.32 (S₁V₄) which was significantly affected by interaction of salinity and variety (Figure 16). Control condition showed the maximum value for filled grains in compare to treatments with salinity stress condition irrespective of varieties. Similarly, unfilled grains panicle⁻¹ ranged from 2.36 (S₁V₂) to 34.20 (S₂V₃) where saline condition exerted significant impact resulting in higher number of unfilled grains in compare to control condition irrespective of rice varieties (Figure 16).
Figure 16. Interaction effect of salinity and variety on filled and unfilled grains panicle⁻¹ of boro rice. [S₁ and S₂ indicate control and 150 mM NaCl, respectively. V₁, V₂, V₃, V₄ and V₅ indicate BINA dhan10, BINA dhan8, BRRI dhan29, BRRI dhan47 and BRRI dhan67, respectively. Mean was calculated from three replicates for each treatment and significance of values were tested at p ≤ 0.05 applying LSD test]
4.5.5 Panicle length
Interaction of salinity and rive variety exerted significant impact on panicle length of rice (Figure 17). Panicle length ranged from 15.72 cm (S₂V₄) to 25.59
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cm (S₁V₅) where control condition had longer panicle in rice plants than salinity stressed condition irrespective of the varieties of rice.
Figure 17. Interaction effect of salinity and variety on panicle length of boro rice. [S₁ and S₂ indicate control and 150 mM NaCl, respectively. V₁, V₂, V₃, V₄ and V₅ indicate BINA dhan10, BINA dhan8, BRRI dhan29, BRRI dhan47 and BRRI dhan67, respectively. Mean was calculated from three replicates for each treatment and significance of values were tested at p ≤ 0.05 applying LSD test]
4.5.6 Weight of 1000-grains
Interaction of salinity and variety of rice exerted significant impact on weight of 1000-grains of rice (Figure 18). Weight of 1000-grains ranged from 13.18 g (S₂V₃) to 23.54 g (S₁V₄) where control condition had heavier weight of 1000- grains in rice plants than varieties under salinity stressed condition. Hossain (2011) concluded that at the highest (12 dS m⁻¹) level of salinity, significantly better performance for 1000-grains weight was given by Heera while BRRI dhan40 was the most badly affected one by salinity.
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Panicle length (cm)
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Figure 18. Interaction effect of salinity and variety on weight of 1000-grains of boro rice. [S₁ and S₂ indicate control and 150 mM NaCl, respectively. V₁, V₂, V₃, V₄ and V₅ indicate BINA dhan10, BINA dhan8, BRRI dhan29, BRRI dhan47 and BRRI dhan67, respectively. Mean was calculated from three replicates for each treatment and significance of values were tested at p ≤ 0.05 applying LSD test]
4.5.7 Grain yield
Interaction of salinity and rice variety exerted significant effect on grain yield of rice (Figure 19). Grain yield ranged from 20.53 g (S₂V₄) to 32.90 g (S₁V₂) where varieties under control condition had higher grain yield of rice than varieties salinity stressed condition. Hossain (2011) concluded that at the highest (12 dS m⁻¹) level of salinity, significantly better performance for grain yield hill⁻¹ was given by Heera while BRRI dhan40 was the most badly affected one by salinity.
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Weight of 1000-grains (gm)
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Figure 19. Interaction effect of salinity and variety on grain, straw and biological yield of boro rice. [S₁ and S₂ indicate control and 150 mM NaCl, respectively.
V₁, V₂, V₃, V₄ and V₅ indicate BINA dhan10, BINA dhan8, BRRI dhan29, BRRI dhan47 and BRRI dhan67, respectively. Mean was calculated from three replicates for each treatment and significance of values were tested at p ≤ 0.05 applying LSD test]
4.5.8 Straw yield
Interaction of salinity and rice variety exerted significant effect on straw yield of rice (Figure 19). Straw yield ranged from 19.28 g (S₂V₅) to 31.54 g (S₁V₅) where rice varieties under control condition had higher straw yield than rice varieties under salinity stressed condition.
4.5.9 Biological yield
Interaction of salinity and rice variety exerted significant effect on biological yield of rice (Figure 19). Biological yield ranged from 39.79 g (S₂V₄) to 63.52 g (S₁V₂) where varieties under control condition had higher biological yield of rice than varieties under salinity stressed condition.
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Figure 20. Interaction effect of salinity and variety on harvest index of boro rice. [S₁ and S₂ indicate control and 150 mM NaCl, respectively. V₁, V₂, V₃, V₄ and V₅ indicate BINA dhan10, BINA dhan8, BRRI dhan29, BRRI dhan47 and BRRI dhan67, respectively. Mean was calculated from three replicates for each treatment and significance of values were tested at p ≤ 0.05 applying LSD test]
4.5.10 Harvest index
Interaction of salinity and rice variety had significant effect on harvest index of rice (Figure 20). Harvest index ranged from 49.86% (S₁V₅) to 56.07% (S₁V₃).
Rice varieties under control condition had higher harvest index values than varieties under salinity stressed condition.
4.6 Interaction effect of micronutrients and variety on growth, yield