The document summarizes the role of various bio-regulators (plant growth regulators) in vegetable production. It discusses the types of natural and synthetic bio-regulators and their major functions. Some key uses of bio-regulators in vegetables include enhancing seed germination and breaking dormancy, inducing flowering and fruit set, altering sex expression, stimulating parthenocarpy and hybrid seed production, and inducing fruit ripening and boosting yields. For example, treatments with auxins like IAA and IBA or gibberellins like GA3 have been shown to improve seed germination and yield in crops like okra, tomato and bell pepper.

2. Role of Bio-regulators in
Vegetable Production
Course title : Master’s seminar
Course No. : APV-600
Speaker : Sajal Debbarma
Id.No: 48052

3. INTRODUCTION
 Bio-regulators are endogenous or synthetically produced substances
that can control one or more specific biochemical and physiological
functions of many species probably by their influence on gene and
enzyme interactions (Olaiya, 2013).
 Other terms used for Bio–regulator are Plant growth regulator (PGR)
or Growth hormone.
 Account for 5-10% of the world agrichemical sales. (Mori, 2011)

4.  TYPES OF BIO-
REGULATOR
 Natural bio-regulator- Auxins,
Gibberellins, Cytokinins, Ethylene,
Abscisic acid
Fig : GA3
 Synthetic bio-regulator- IBA, 2,4-D,
NAA, 2,4,5-T, Alar, Morphactin,
Cycocel, Maleic hydrazide etc.
Fig : TIBA
Fig : GA3

5.  Major groups of bio-regulators
 Auxins
Gibberellins
Cytokinins
Ethylene
Abscisic acid

6. AUXINS
 Types of Auxins
Natural : Indole 3 acetic acid (IAA).
 Synthetic : IBA, NAA,2,4-D.
Fig : IBA powder
Fig: NAA

7.  FUNCTIONS OF AUXINS

10.  Functions of Gibberellins

11.  Functions of Cytokinins
1. Cell division :The most important biological effect
of kinetin on plants is to induce cell division especially
in carrot root tissue, pea callus etc.
2. Cell enlargement : Like auxins and gibberellins, the
kinetin may also induces cell enlargement in the leaves
of Phaseolus vulgaris, pumpkin cotyledons etc.
3. Flower induction: Cytokinins can be employed
successfully to induce flowering in short day plants.
4. Dormancy of seeds: Like gibberellins, the dormancy
of certain light sensitive seeds such as lettuce can also
be broken by kinetin treatment.
5. It delays leaf senescence.
Fig : Kinetin

12. Functions of Abscisic acid
Growth Inhibiters: ABA inhibits shoot growth but has
less effect on root growth.
Induces bud dormancy and seed dormancy.
Induces tuberisation.
Induces senescence of leaves , abscission of leaves, flowers
and fruits.
 Stomatal closing.

13.  Functions of Ethylene

14. CommerCial uses of
bio- regulators in
vegetable Crops

15.  Seed Germination
Pre-sowing treatment of seed with growth regulators has been reported to
enhance seed emergence.
 In tomato, pre sowing seed treatment with 100 ppm IAA, IBA and
NAA enhanced the seed germination ( Olaiya et al.,2009).
 Pre-sowing treatment of seed with GA3 and KNO3 @ 50 ppm
enhanced the germination of endive and chicory, respectively
(Tzortzakis, 2009).
In muskmelon, soaking of seeds in ethephon at 480 mg/liter of
water for 24 hours improves germination in muskmelon at low
temperature (Meena, 2015).

16. Effect of plant bioregulators on seed yield,
germination and vigour in okra [ Abelmoschus
esculentus (L.) Moench ]
SL. NO. TREATMENTS GERMINATION
%
SEEDLING
LENGH
( cm)
1 Control 79.50 29.05
2 NAA @ 50 ppm 85.00 28.39
3 NAA @ 100 ppm 94.67 27.39
4 NAA @ 150 ppm 89.83 27.07
5 GA3 @ 50 ppm 87.50 27.63
6 GA3@ 100 ppm 87.50 26.34
7 GA3 @ 150 ppm 84.83 25.41
CD at 5% 5.02 3.67
Source : Khan et al., 2013

17.  Seed dormancy
 Seed dormancy is main problem in potato and Lettuce.
Chemicals which have been reported to break the rest period are GA,
Ethylene chlorhydrin and Thiourea.
Soak the tubers in 1% aqueous solution of thiourea for 1 hour or solution
containing 5-10 ppm GA3 for 10- 20 minutes can be used to break the
dormancy of potato ( Byran , 1989)
Lettuce is another vegetable in which treatment with GA3 or Cytokinin has
been reported to break seed dormancy induced by high temperature.

18.  Flowering
 Induction of flowering which otherwise fails to flower has also been
reported with the use of various growth regulators.
 NAA 50 ppm has been reported to induce early flowering in paprika
( Kannan et al., 2009)
 Plants sprayed with 300 ppm GA3 were earliest to flower and
recorded highest number of fruits and yield per plant in
tomato ( Sharma et al.,1992)

19. Effect of Plant Growth Regulators on Yield Contributing
Characters and Yield of Bell Pepper (Capsicum annum) Varieties
VARIETIES TREATMENTS Days to 1st
flowering
No. of flowers
/plant
Days to 1st harvest
BARI Misti morich-1
Control 57.33 29.67 122.33
GA3 at 100 ppm 53.67 30.33 113.67
4-CPA at 2000 ppm 49.67 32.67 101.67
Litosen at 1000
ppm
50.33 31.33 109.67
Lamuyo
Control 52.67 31.67 119.33
GA3 at 100 ppm 51.67 32.67 109.33
4-CPA at 2000 ppm 48.67 33.33 103.67
Litosen at 1000
ppm
50.00 32.67 107.00
CD at 5% 2.623 1.838 0.896 9.976
Source: Das et al.,2015Source: Das et al.,2015

20.  Sex expression
 The treatment with growth regulators has been found to change sex expression
in cucurbits, okra and pepper.
 Female inducing hormones are Auxin and Ethylene whereas male inducing
hormone is Gibberellic acid.
 Application of ethephon at two true leaf stage to both bush and trailing forms
of Cucurbita maxima and C. pepo caused suppression of male flowers, earlier
production and increase in numbers of female flowers. Thus gave rise to an
increase in the ratio of female to male flowers per plant (Hume et al., 1983)

21. Altered sex expression by plant growth regulators:
An overview in medicinal vegetable bitter gourd
(Momordica charantia L.)
(Source : Mia et al.,2014)
Treatments Days to flower Node no. of first
flower
Flowers per plant Sex ratio
male:
femaleMale Female Male Female Male Female
Control 38 53 10.50 12.20 310 27.42 11.31
GA3@ 50
ppm
35 49 9.55 11.80 383 29.42 13.02
NAA@ 50
ppm
37 41 8.45 7.00 250 35.14 7.48
NAA@100
ppm
36 46 10.75 8.90 285 33.43 8.11
CEPA@100
ppm
40 42 8.50 6.50 210 38.33 5.48
CEPA@300
ppm
33 43 6.25 9.70 342 31.43 10.88
CD at 5% 0.95 0.75 0.35 0.85 12.45 1.65 0.55

22.  Parthenocarpy
Plant growth regulators helps to stimulate the fruit development
without fertilization ( Parthenocarpy).
2,4-D at 50 ppm when applied at anthesis showed better
performance over other in parthenocarpic fruit development in
kakrol ( Chowdhury et al ,2007).
Seed treatment with 2,4-D @ 2-5ppm gives early fruit set and
leads to parthenocarpy in tomato. ( Meena, 2015)
 At G.B.P.U.A.&T. Pantnagar, staminate flowers were induced in
parthenocarpic line of cucumber through use of plant growth
regulator GA3@1500 ppm and silver nitrate @200-300ppm by four
sprays at 4 days interval (Singh and Ram, 2004)

24.  Stimulation of fruit Set

25. Fruit Set and Yield Enhancement in Tomato (Lycopersicon
esculentum Mill.) Using Gibberellic Acid and 2,4-Dichlorophenoxy
Acetic Acid Spray
(Source
Treatments Fruit set (%) Total no. of
fruits /plant
Fruit weight
(g)
Fruit yield
/plant (g)
GA3@ 0 ppm 39.8 10.9 47.3 434.7
GA3@ 5 ppm 53.4 14.2 47.6 497.7
GA3@ 10 ppm 54.0 14.7 47.6 506.2
GA3@15 ppm 53.8 14.2 50.9 574.3
2,4-D@ 0 ppm 43.7 12.2 45.6 436.2
2,4-D@ 5 ppm 55.0 17.2 51.4 587.9
2,4-D@10 ppm 52.1 14.8 53.2 515.6

26. Contd….
fruit set in unsprayed (control) plant fruit setting in tomato after the
spray of 2,4 D @ 5ppm
(Source : Luitel et al., 2015)

27.  Hybrid seed production
Bioregulators have also been used for maintenance of gynoecious
lines in cucurbits.
Growth regulator like GA3 (1,500-2000ppm) and chemical like silver
nitrate (200-300ppm) induces the male flowers on gynoecious
cucumber (Meena, 2015).
Exogenous application of silver thiosulphate (300-400ppm) induces
the male flower in gynoecious muskmelon (Meena, 2015).

28.  Gametocides
Some PGR’s posseses gametocidal action to produce male sterility which can
be used for F1 hybrid seed production.
MH at 100 to 500 ppm appeared most effective in inducing a high level of male
sterility in eggplant, okra, peppers and tomato, without detrimental influence on
female fertility (Saimbhi et al., 1978).
 A high concentration of gibberellic acid (2%) was found to act as a gametocide
for the common onion (Allium cepa L.), when sprayed in the beginning of the
bolting process (Meer et al., 1973).

29. Gibberellic acid as gametocide for cole crops
Fig : Male sterility in cauliflower as induced by GA4.
Left : Male fertile flowers Right : Male sterile
flowers (Source : Meer and Dam, 1979)(Source : Meer and Dam, 1979)

30.  Fruit ripening
 Ethephon, an ethylene releasing compound, has been reported to induce
ripening in tomato and pepper.
 Application of ethephon at 1000 mg/L at turning stage of earliest fruits
induced early ripening of fruits thus increasing the early fruit yield by 30-
35%.
 Post-harvest dip treatment with ethephon at 500-2000 mg/L has also been
reported to induce ripening in mature green tomatoes. (Gould, 1992)

31. Effect of Post harvest Treatments on Shelf Life of Tomato (Lycopersicon
esculentum Mill.) Fruits during Storage
Treatments Physiological loss of
weight (%)
Decay (%) Storage life (Days)
T1 (GA3@0.1%) 6.50 8.89 18
T2 (GA3@0.3% 9.87 11.11 15
T3 (GA3@0.5%) 11.85 11.11 14
T4 (Cacl2@0.5%) 8.77 13.33 15
T5 (Cacl2@1%) 6.64 8.87 17
T6 (Cacl2@1.5%) 5.35 8.86 17
T7(SA@0.1mM) 11.56 11.11 13
T8 (SA0@0.2mM) 9.95 13.33 14
T9 (SA@0.4mM) 6.78 8.89 17
T10 (Control) 19.89 24.44 10
CD (5% level) 2.28 9.27
Source: Pila et al.,2010

32.  Fruit yield
1. TOMATO
 Spraying with 60 ppm GA3 10 days before transplanting increased the yield per ha
of variety Roma ( Naeem et al., 2001)
 Foliar sprays of 2,4-D @ 6 ppm gave highest yield of tomato ( Patel et al., 2014).
2. BRINJAL
 Foliar sprays of 4 ppm 2,4-D gave the highest yield of brinjal.( Patel et al, 2012)
 Seed treatment with 10ppm GA3 or IAA gave the highest yield in brinjal (Sharma
et al, 1992).
3. CHILLI
 Foliar sprays of 2 ppm 2,4-D, 40 ppm NAA and 10 ppm GA3 gave 28.75%, 13.61%
and 2.30% higher fruit yield over control, respectively. ( Chaudhoury et al., 2006).
 Spraying plants with 10 ppm NAA gave significantly highest fruit yield (277.8
g/plant). ( Sultana et al., 2006)

33. Effect of GA3 and NAA on growth and yield
of tomato
Treatments Percent
fruit
set
No. of
fruits/
plant
Fruit
weight
(g)
Fruit
length
(cm)
Fruit width
(cm)
Rind
thickness
(cm)
Fruit yield
(q/ha)
Control 30.6 13.2 80.5 4.3 4.4 0.40 380.7
GA3 20 ppm 35.4 18.7 85.1 4.8 4.92 0.45 396.2
GA3 40 ppm 40.2 22.7 120.2 5.06 5.21 0.48 418.6
GA3 60 ppm 47.3 26.2 125.7 5.92 6.20 0.52 446.5
GA3 80 ppm 51.6 30.2 130.8 6.46 6.86 0.56 483.6
NAA 25
ppm
32.1 18.5 84.1 4.6 4.72 0.44 390.5
NAA 50
ppm
37.7 21.7 118.2 4.82 4.90 0.45 402.7
NAA 75
ppm
44.5 23.4 121.8 5.78 6.11 0.50 433.6
NAA 100
ppm
49.1 24.7 128.6 6.08 6.38 0.55 474.2
CD (0.05) 3.42 9.50 6.48 1.01 NS 1.23 12.6
Source : Singh et al., 2013

34. Contd…
Fig : Plant height of tomato as affected by GA and NAA

35. Effect of GA3 and kinetin on growth, yield and quality of broccoli
(Brassica oleracea var. italica)
Treatments Plant height
(cm)
No. of
leaves
Days to
central
head
formation
Days to
secondary
head
formation
Head size
(cm3)
Total
yield /ha
(q)
GA3 20 ppm 60.73 13.73 61.40 70.93 1306.65 169.80
GA3 40 ppm 63.07 13.47 61.53 71.33 1369.48 175.29
GA3 60 ppm 60.93 14.53 57.86 66.20 1496.47 176.11
kinetin 20 ppm 55.40 14.80 59.86 69.60 1356.81 163.88
kinetin 40 ppm 61.47 15.67 59.87 69.93 1412.67 174.94
kinetin 60 ppm 60.80 14.53 60.40 71.60 1509.20 185.16
GA3 10 ppm +
kinetin 10 ppm
59.67 15.33 58.86 69.60 1272.16 170.58
GA3 20 ppm +
kinetin 20 ppm
57.843 15.20 61.13 71.53 1518.83 187.05
GA3 30 ppm +
kinetin 30 ppm
63.77 16.00 60.73 70.06 1542.66 189.67
control 58.27 13.33 63.60 74.53 884.64 145.15
C.D at 5% 5.09 2.01 2.62 2.94 481.70 42.24
Singh et al., 2010

36. Effect of bio-regulators on performance of tomato under naturally
ventilated polyhouse during off- season
Treatments
Plant height
(cm)
Days to 50%
flowering
Days to 50%
fruiting
Fruit setting (%)
July August July August July August July August
GA310 ppm 120.19 108.38 46.50 49.50 53.00 54.50 65.72 58.70
GA325 ppm 127.25 120.13 47.25 50.00 51.00 52.40 69.80 60.26
PCPA 50
ppm
113.50 80.38 41.75 44.50 48.25 49.30 61.74 54.87
NAA 10
ppm+ 1ppm
Boron
107.50 74.13 37.67 39.40 55.75 57.75 50.34 47.25
Control 70.67 54.13 35.65 37.60 68.40 70.20 29.24 20.92
CD (5%) 2.90 3.16 1.91 1.74 3.62 3.13 3.94 3.66
Source :Phukan et al.,

37. Contd….
Treatments
Number of
fruits per plant
Average fruit
weight
(g)
Fruit yield
(g/plant)
Fruit yield
(kg/m2)
July August July August July August July August
GA310 ppm 21.50 18.50 58.00 49.82 1247.09 679.66 4.61 2.51
GA325 ppm 23.00 21.00 68.00 62.27 1563.23 1307.36 5.79 4.84
PCPA 50
ppm
23.67 20.72 60.00 57.48 1421.64 1191.49 5.26 4.41
NAA 10
ppm+ 1ppm
Boron
20.54 16.00 51.00 43.96 1045.98 703.17 3.87 2.60
Control 11.25 10.00 45.00 39.72 507.57 397.32 1.88 1.47
CD (5%) 2.32 2.65 3.70 2.61 152.74 292.34 0.56 1.08

38. Effect of bio-regulators on Quality of
Vegetables
Growth
Regulators
Concentration
(ppm)
Method of
Application
Crops Effect on Quality
GA3 15 Foliar spray Muskmelon Improve rind
thickness
GA3 5-15 Foliar spray Cauliflower,
cabbage
Increases head or
curd size
GA3 50 Foliar spray Lettuce and
Chinese
cabbage
Increases dry
matter, protein and
ascorbic
acid content
PCPA 50 Foliar spray Tomato Increases sugar
and vitamin-C, but
reduces acidity

39. Contd….
CCC 250 Foliar spray Potato Increases TSS and
vitamin-C content in
tuber
MENA
(vapour) +
CIPA
5000 Post-harvest dip Potato Reduces sprouting
and rooting of tuber
in
storage
Cytozyme 1% Foliar spray Garden pea Increases vitamin-C,
reducing sugars and
total sugars
Ethephon 250 Foliar spray Tomato Increases TSS
NAA 50-70 Seed treatment Chilli Increases amino acid
and vitamin-C content
in fruits
Mixtallol 1-2 Foliar spray Potato Increases starch,
reducing sugars, non-
reducing
sugars, total sugars,
and protein
Bahadur and Singh, 2014

40. BIOREGULATORS FAVOURABLY AFFECT THE LEVELS
OF VITAMINS AND SUGARS IN TOMATO FRUIT TISSUES
Genotypes
Ascorbic acid (mg/100 g)
Control 100 ppm IAA 100 ppm IBA 100 ppm NAA Mean
NHLy 11 12.87 14.77 16.78 11.97 14.09
NHLy 12 20.06 20.16 20.23 19.67 20.08
NHLy 13 15.36 17.28 16.87 19.88 17.34
NHLy 15 16.67 18.23 19.61 17.97 18.12
NHLy 16 18.97 20.36 19.68 20.14 19.78
Mean 16.76 18.16 18.63 17.92
Source: Olaiya, 2011Source: Olaiya, 2011

41. Contd…..
Genotypes
Total sugar (g/100 ml juice)
Control 100 ppm IAA 100 ppm IBA 100
ppm
NAA
Mean
NHLy 11 3.02 3.11 3.26 2.67 3.01
NHLy 12 3.06 2.47 3.23 3.11 2.96
NHLy 13 2.27 2.46 2.30 2.22 2.31
NHLy 15 2.51 2.47 3.13 3.01 2.78
NHLy 16 2.61 2.81 3.22 2.76 2.85
Mean 2.69 2.66 3.02 2.75

42. Works at G.B.P.U.A&T.,
Pantnagar

43. Effect of plant bioregulators on
chilliPlant bioregulators
(ppm)
Total leaf area
per plant (cm)
Shoot fresh wt. (g) Root dry wt (g) Root fresh wt. (g)
NAA 20 2286.93 167.53 26.80 32.66
NAA 40 2970.90 210.20 28.40 39.06
NAA 60 2118.36 187.13 28.20 24.73
GA3 10 2239.00 153.06 24.00 27.26
GA3 20 2517.76 164.46 25.20 28.80
GA3 30 2749.83 172.66 26.00 29.93
Ethepon 50 2285.10 160.93 23.73 26.26
Ethepon 100 2594.33 198.86 24.80 27.86
Ethepon 150 2847.86 214.20 26.20 32.66
2 ,4- D 2 2061.43 200.93 24.20 25.27
2, 4- D 4 1583.36 221.33 31.80 47.26
2 ,4 -D 6 1351.73 156.06 25.66 26.20
PP333 100 1923. 45 158.46 26.73 35.93
PP333 200 1770.10 148.33 27.60 38.73
PP333 300 1552.63 133.73 28.00 41.53
Control 2040.93 158.53 24.86 26.20
CD at 5% 53.81 8.49 1.37 3.33
Source: Joshi et al., 2001

44. Contd….
Plant bioregulators (ppm) Shoot dry wt.
(g)
No. of seeds per
fruit
Weight of seed
(mg)
Fruit yield per
plant
NAA 20 61.00 40.66 194.66 232.73
NAA 40 63.26 43.13 196.66 274.03
NAA 60 65.60 45.00 200.66 246.46
GA3 10 47.40 36.60 160.33 231.80
GA3 20 52.13 30.46 150.00 234.53
GA3 30 57.13 25.80 123.33 240.73
Ethepon 50 42.26 35.73 176.66 229.26
Ethepon 100 45.20 34.13 153.33 233.73
Ethepon 150 72.86 33.20 160.00 240.80
2 ,4- D 2 44.66 41.46 173.33 276.80
2, 4- D 4 52.80 39.86 168.33 240.93
2 ,4 -D 6 67.46 36.13 165.66 228.66
PP333 100 43.13 41.53 200.00 265.20
PP333 200 35.13 43.46 203.33 271.13
PP333 300 27.46 43.86 208.33 282.20
Control 42.43 32.93 156.66 209.73
CD at 5% 8.49 3.67 7.01 10.023

45. EFFECT OF GROWTH REGULATORS ON SUMMER
TOMATO (Lycopersicon esculentum Mill.)
Treatments Days to
first set of
fruit
Percentag
e of fruit
set
Days to
first
harvest
Weight
of fruit
(g)
No. of
fruits per
plant
TSS
(%)
Ascorbic
acid
(mg/100 g
of fruit)
GA3@10 ppm 39.89 56.84 59.66 35.26 41.05 13.07 25.20
GA3@ 25
ppm
38.00 51.87 57.55 33.40 42.91 13.29 26.22
2,4-D @ 1
ppm
41.44 54.35 62.55 35.20 43.99 12.56 17.27
2,4-D @ 5
ppm
40.67 65.05 61.44 44.15 51.32 13.20 17.58
NAA @ 0.1
ppm
42.89 58.38 63.67 36.37 44.67 10.78 29.17
NAA @ 0.2
ppm
42.00 60.21 62.55 37.54 46.32 10.46 30.21
Control 42.89 50.18 63.67 32.52 35.67 11.99 22.67
CD at 5% 0.590 1.68 0.612 1.045 0.846 0.811 0.482
Source : Mehta ,1973

46.  Constraints in the Use of Growth Regulators
• The cost of developing new PGR is very high due to which they are very
much costly.
 Screening for PGR activities entails high costs and much difficult.
 Some synthetic plant growth regulators causes human health hazards.
 It is difficult in identification of proper stage of crop at which the growth
regulators should be applied.
 Lack of support from agricultural researchers in public and private
sectors.
 Lack of basic knowledge of toxicity and mechanism of action.

47. Precautions in Bio- regulator Application
Growth regulators should be sprayed preferably in the afternoon.
 Avoid spraying in windy hours.
 Spray should be uniform and wet both the surface of leaf.
 Add surfactant or adhesive materials like Teepol with growth regulators @ 0.5-
1.0 ml/l solution.
 Use growth substances at an appropriate stage of plant growth.
Chemical should be completely dissolved before use.
Use always fresh solution of plant growth regulators.
 Solution should be always being prepared in distilled water only..
 Wash the machine or pump after each spraying.
 Repeat the spray within 7-8 hours, if chemical is washed out due to rain.

48. Conclusion
Bio-regulators has an immense potential in vegetable production to increase
the yield and quality of vegetables to better meet the requirements of food
supply in general. But more research is needed to develop simple,
economical and technical viable production system of bio-regulator.
Bioregulators must be toxicologically and environmentally safe.