Table 2 Effect of growth regulators and thermal regimes on net photosynthetic rate-Pn (µ mol m−2 sec−1), fiber quality components, number of sympodial branches per plant and boll weight (g) under glass house conditions.

From: Exogenously applied growth regulators protect the cotton crop from heat-induced injury by modulating plant defense mechanism

Thermal regimes

Regulators

Pn

Fiber fineness (micronaire)

Fiber length (mm)

Fiber strength (g/tex)

No. of sympodial branches per plant

Boll weight (g)

32/20 °C

H2O2 (30 ppm)

28.4 ± 0.53 a

4.0 a ± 0.20

28.7 a ± 1.5

30.9 a ± 1.7

23.3 a ± 0.56

3.7 a ± 0.19

SA (70 ppm)

25.6 ± 0.50 b

3.9 a ± 0.19

27.8 a ± 1.3

30.1 a ± 1.6

22.8 a ± 0.44

3.8 a ± 0.20

MLE (30 times diluted)

24.9 ± 0.50 b

4.2 a ± 0.23

27.8 a ± 1.6

29.7 a ± 1.4

23.2 a ± 0.41

3.8 a ± 0.21

ASA (70 ppm)

25.1 ± 0.41 b

4.1 a ± 0.21

28.1 a ± 1.4

29.8 a ± 1.5

22.9 a ± 0.40

3.7 a ± 0.18

45/30 °C

Control

21.5 ± 0.52 c

3.2 b ± 0.16

18.6 b ± 1.0

21.8 b ± 1.1

14.8 b ± 0.31

2.6 b ± 0.17

H2O2 (30 ppm)

26.1 ± 0.49 a

3.8 a ± 0.19

23.0 a ± 1.1

26.9 a ± 1.3

17.6 a ± 0.37

3.4 a ± 0.14

SA (70 ppm)

21.9 ± 0.46 c

3.2 b ± 0.16

18.8 b ± 0.9

20.7 b ± 1.0

14.5 b ± 0.33

2.7 b ± 0.16

MLE (30 times diluted)

23.7 ± 0.49 b

3.7 a ± 0.18

21.6 a ± 1.2

26.8 a ± 1.2

17.4 a ± 0.43

3.2 a ± 0.13

ASA (70 ppm)

24.0 ± 0.39 b

3.7 a ± 0.17

21.8 a ± 1.3

25.7 a ± 1.3

17.3 a ± 0.31

3.1 a ± 0.15

38/24 °C

Control

15.9 ± 0.31 c

3.5 b ± 0.18

23.9 c ± 1.4

25.2 b ± 1.1

19.7 b ± 0.50

3.2 a ± 0.17

H2O2 (30 ppm)

21.6 ± 0.36 a

4.0 a ± 0.21

27.1 a ± 1.5

29.0 a ± 1.5

22.1 a ± 0.45

3.6 b ± 0.18

SA (70 ppm)

15.0 ± 0.29 c

3.4 b ± 0.17

22.6 c ± 1.1

24.1 b ± 1.2

19.7 b ± 0.39

3.3 a ± 0.19

MLE (30 times diluted)

17.8 ± 0.32 b

3.9 a ± 0.23

25.8 b ± 1.2

27.7 a ± 1.4

22.9 a ± 0.53

3.3 b ± 0.16

ASA (70 ppm)

17.9 ± 0.37 b

3.9 a ± 0.20

26.0 a ± 1.4

28.6 a ± 1.6

22.8 a ± 0.52

3.7 a ± 0.19

LSD

1.42

0.21

1.43

1.51

1.02

0.20

  1. Mean of three replications (n = 3) ± SE and variants having same alphabets are not statistically significant at P˂ 0.05. Main factors and interaction are significant at P˂ 0.01. By using the LSD of the interaction between growth regulators and thermal regimes, lettering is done separately for each thermal regime.
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