VARIOUS GROWTH INHIBITORS AND RETARDANTS THEIR ROLE IN YIELD AND QUALITY OF VEGETABLE CROPS

VARIOUS GROWTH INHIBITORS AND RETARDANTS THEIR ROLE IN YIELD AND QUALITY OF VEGETABLE CROPS

2. SUBMITTED BY:
ID No.15MSASS009
15MSASS042
15MSASS038
M.Sc. (Ag.) SOIL SCIENCE
VARIOUS GROWTH INHIBITORS AND RETARDANTS THEIR ROLE
IN YIELD AND QUALITY OF VEGETABLE CROPS
SUBMITTED TO: 2016
Dr. S. SARAVANAN
ASSOCIATE PROF.
DEPT. OF HORTICULTURE
DEPARTMENT OF HORTICUTURE
ALLAHABAD SCHOOL OF AGRICULTURE
SAM HIGGINBOTTOM INSTITUTE OF AGRICULTURE, TECHNOLOGY &
SCIENCES
[Formerly-Allahabad Agricultural Institute]
Deemed-to-be-University
ALLAHABAD-211 007, U.P., INDIA

3. PlantGrowthRegulator(PGR)alsocalledasbio-stimulantsorbio-
inhibitors,areorganiccompounds,otherthanplantnutrients,that
modifyphysiologicalprocessesinplant.PGRactsinsideplantcellsto
stimulateorinhibitspecificenzymeorenzymesystemsandhelp
regulateplantmetabolism.
PGRnaturallyproducedinplantswhichcontrolthegrowthandother
physiologicalfunctions,slightlyawayfromitsplaceofproductionand
activeinveryminutequantities.
Introduction

4. Growthregulatingsubstancesmaybeclassified
intofollowingcategories-
1.Auxins,e.g.Indoleaceticacid(IAA)
2.Gibberellins,e.g.Gibberellicacid(GA)
3.Cytokinins,e.g.Kinetin,Zeatinetc
4.Ethylene
5.Dormins,e.g.Abscissicacid(ABA),Phaseicacid,Xanthoxin
6.Floweringhormones,e.g.Florigen,Anthesin,Vernelin
7.Phenolicsubstances,e.g.Coumarin.
8.Syntheticgrowthretardants,e.g.CCC,AMO1618,Phosphon
D,Morphactins,Malformins,Maleichydrazide(MH)etc.
9.Miscellaneoussyntheticsubstances,e.g.Syntheticauxins
(IBA,NAA,2,4-Dand2,4,5-T),Syntheticcytokinins(6-BA,
6-BAP)etc.

5. Plant growth inhibitors-
Natural inhibitors –Benzoic acid, Caumaricacid
Synthetic –MH, TIBA, Dormin(ABA)
Growth retardant-
Organic chemical which retard the stem elongation &
increase the green colourof the leaves. They make the dwarf.
Increase chlorophyll in lvs.
Synthetic retardant:CCC, Phosphon-D, AMO-1618, Ancimedol
ABA normal condition –decrease ABA, Stress condition-
increase ABA

6. Role of
Plant Growth Inhibitors

7. 1.Succinate-dehydrogenase:forextendingShelflife&storage
stabilityofvegetables&fruits.Applicationpriortotheharvest.
2. Senescence is inhibited by cytokinins .
3.Chlormequatinhibitsgibberellinsynthesis&leadstoreduced
extensiongrowth.
4. (MH)60 : for field application to prevent
sprouting in storages

8. 5. Formation of an abscission layer at the base of petiole or
pedicel result in shedding of leaves , flower or fruits. But auxin
inhibit Abscision as they prevent formation of abscission layer.
.
AuxinSpray Prevent Premature Fruit Abscission and Increase in Yield.
a)AuxinSprayed;
b)b) Auxinnot Sprayed

9. 6.In higher concentration inhibit the growth
& exert toxic effect on plant .
7. MH-is also used as a pre-harvest treatment for onion,
potato & other crops to inhibit sprouting of the tuber or bulbs
while in store.
8. CCC (chloromequat) :
. Promote branching
E.g. Geranium, bouganvellia.
.chemical pruning
eg. Apple –enhance size and colour

10. .
9. Selective weed killers and herbicides
2, 4 -D (2, 4 dichloro phenoxy acetic acid) is used to
destroy broad leaved weeds. It does not affect mature
monocotyledonous plants.

11. .
10. Spraying of Beta Naphoxy Acetic Acid for
uniform size of tomato.

12. 11.Abscisic acid
In 1940s, scientists started searching for hormones that would inhibit growth
and development, what Hemberg called dormins.
In the early 1960s, Philip Wareing confirmed that application of a dormin to
a bud would induce dormancy.
F.T. Addicott discovered that this substance stimulated abscission of cotton
fruit. he named this substance abscisin. (Subsequent research showed that
ethylene and not abscisin controls abscission).
Abscisin is made from carotenoids and moves nonpolarly through plant
tissue.

13. ROLE
Abscisic acid is produced chiefly in mature green leaves
and in fruits.
suppresses bud growth and promotes leaf senescence
also plays important role in controlling stomatal opening
and closing

14. 12.Ethylene
In1901,DimitryNeljubowidentifiedthatabyproductof
gascombustionwasethylenegasandthatthisgascould
affectplantgrowth.Heobservedthatdarkgrownseed
lingsgrowinginthelaboratoryexhibitedsymptomsthat
werelatertermedastripleresponses.
Denny(1924), reported that ethylene is highly effective in
inducing fruit ripening.

15. Role of ethylene
§Gaseousinformandrapidlydiffusing.
§Gasproducedbyoneplantwillaffectnearbyplants.
§Fruitripening.
§Epinasty–downwardcurvatureofleaves.
§Encouragessenescenceandabscission.
§Initiationofstemelongationandbuddevelopment.
§Flowering-Ethyleneinhibitsfloweringinmostspecies,but
promotesitinafewplantssuchaspineapple,bromeliads,and
mango.
§SexExpression-Cucumberbudstreatedwithethylenebecome
carpellate(female)flowers,whereasthosetreatedwith
gibberellinsbecomestaminate(male)flowers.

16. Horticultural uses of growth inhibitors
Rooting of cutting-SADH
Inhibition of sprouting of
tuber-MH
Promotion of flowering-
SADH ( Succinic acid 2,2
dimethyl hydrazide)
Sex expression
Fruit set
Promotion of fruit ripening
•Delay senescence
•Increase vase life
•Retarding growth of plant
•Prevent pre harvest drop
•Prevention logging-CCC
•Increase drought resist -SADH

17. Role of
growth retardant

18. Growth retardant-
Organic chemical which retard the stem elongation &
increase the green colour of the leaves. They make the dwarf.
Increase chlorophyll in lvs.
Synthetic retardant:CCC, Phosphon-D, AMO-1618, Ancimedol
ABA normal condition –decrease ABA, Stress condition-
increase ABA

19. Synthetic Growth Retardants
1.Morphactins
It acts as antiauxin.
It inhibits stem growth and bring about several
morphological abnormalities in leaves, buds and flowers
so known as morphactins.
It inhibit seed germination and cause dwarfisom at high
concentrarion.
Bud dormancy in potato can be prolonged by applying it.
With 2,4-D it is a good weed killar.

20. Morphactins are two types-
flurenol
Chloroflurenol methyl

21. 2 . Maleic hydrazide
Most widely use.
E.g. Succinamic acid ,B-9.
All the growth retardant are readily soluble in water and can be
applied to roots as soil drench or to foliage by spraying.

22. Cont….
Itreducessproutinginpotatoandonion.
MHinhibitscelldivisionandelongation
ofcell,flowerinitiationandfruitset.
Effect can be antagonist by GA.
It is a good weed killar at high
concentration.

23. 3. phosphons:-
Decreases cell division and cell elongation in stem so also
known as anti gibberelins.
It is two type-
a)Phosphon-D
b)Phosphon-S
e.
Effective on a wider range of species.
Eg. Phosphon-D(II), phosphons,cycocel .

24. 4. AMO-1618
Anti gibeerelin
Blocks the biosynthsis of the gibberelin when sprayed on plant tissues.
It reduces stem elongation without hindering cell division in the apical
meristem.
5. CCC (Chlormequat Chloride)
6.Nicotinium:firstgrowthretardanttobetestedonplants(Mitchell
et.al.1949).
Eg.2,4-dichlrobenzylnicotiniumchloride.
7.Quaternaryammoniumcarbamates:
Inhibitsthestemgrowth
Eg.AMO-1618(I)

25. 1.Inpotatotheapplicationofgrowthretardantbeforetuber
sproutingproduceshorter,greener&morenumeroussprouts.
2.Flowering:Phosphon-Dsuppressionofvegetativegrowthleading
toflowerformationinwoodplant.AfterapplicationofPhosphon-D
floweringisinitiatedwithin3weeksofperiod.
3.Daminozide-(Alar,B-9)
Retardgrowth
Stimulateflowering
E.g.Chrysanthemum.

26. 4.B-9delaysthesenescenceofexcisedleavesofbeansevidenced
bygreaterretentionofchlorophyllthereforeduetoapplicationof
retardantsplantappeardarkgreen.
5.Toincreasetheresistanceofplanttowaterstress&draught.
6.Commercialapplicationofthisretardantforpreventingthe
lodgingincitrusplant

27. 7.TheherbicideGlyphosateisusedasagrowthretardantin
sugarcanetostopextensiongrowth.
8.Thegrowthretardant(2-CLOROETHYL) tri-methyl
ammoniumchlorideappliedasasoildrenchtoyoung
tomatoplantwaseffectiveinreducingtheabortionofflower
budsthatoccurredunderwinterconditionintheglasshouse.

28. Role in vegetable production

29. TheapplicationofGA
3at200ppmincreasedthevinelength.
Whereas,MHat400ppmwasfoundtobethemosteffectivein
enhancingthenumberofbranchespervine,numberof
pistillateflowers,fruitlength,fruitdiameter,numberoffruits
pervineandthehighestfruityieldinbittergourdcv.Priya.
(Chovatia et. al., 2010)

30. Chovatia et. al., 2006, Junagadh
Indian J. Hort. 67(Special Issue), November 2010: 254-258

31. Chovatia et. al., 2006, Junagadh
Indian J. Hort. 67(Special Issue), November 2010: 254-258

32. Theapplicationof100ppmmaleichydrazideand100
ppmethephoninducedearlydevelopment,maximizedsex
ratio,yieldandhighernetreturnincucumber.
(Thappaet.al.2011)