PLANT GROWTH REGULATORS IN MANGO

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INTRODUCTION

• Plant growth regulators are organic substances which are produced

in a one part of plant and it translocate to other parts of plant.

• It also available in synthetic form.

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MANGO MALFORMATION

Different methods of checking malformation like pruning of

diseased portions, use of fungicides, plant growth regulators

and de blossoming have been tried with some success. To

control this malady, the affected shoots should be removed

every month and destroyed.

One spray of 200 ppm NAA in October (dissolve 110 g NAA in

some alcohol and make up to 550 litre) is effective in reducing

the incidence of malformation.

Spray of NAA (100 to 200 ppm) during the first week of

October has been worked out to reduce floral malformation.

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CONT..

• Later, four sprays of 250 ppm NAA at weekly intervals from 20th

October onwards have been suggested to reduce the intensity of

malformation to the maximum possible.

• Hence spray of 100 ppm NAA has been suggested instead of 200

ppm NAA.

• Also observed that spraying 200 ppm NAA in first week of October

followed by spraying of 500 ppm of ethrel at bud inception stage

during February was highly effective in reducing floral malformation.

• Spray of 400 ppm of Ethephon at bud inception stage reduced the

floral malformation significantly.

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CONT.

• Increase in floral branches and yield was observed by the

spraying of ethrel (250 or 500 ppm) or uniconazole 500 ppm

in the month of December.

• The gibberellic acid at 50 ppm causes delayed panicle

emergence, increased number of perfect flowers and

increased pollen viability.

• Sprays in the months of October and November cause 50%

reduction in malformation.

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FRUIT DROP

• Fruit drop may be controlled to some extent by

the spray of 20 ppm of 2, 4-D (2g in 100 litres of

water) in the last week of April or in the first week

of May in Langra and Dusehari cultivars.

• Post harvest treatment with GA3 at 200 ppm has

been found highly effective in retarding ripening of

Mallika, Alphonso and Kesar mangoes.

• GA3 treatment retarded the total loss in weight,

chlorophyll and ascorbic acid content and

reduced amylase and peroxidase activity during

ripening.

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CONT.• Similarly pre harvest application of GA3 also

influenced the post harvest ripening behavior

of mango.

• Embryo abortion, climatic factors , disturbed

water relation, lack of nutrition, attack of

disease and pest, hormonal imbalances are

the major factors that lead to fruit drop.

• A spray of Alar (B-Nine) @ 100 ppm or 20 ppm

2,4-D (2g. in 100 l. water) in the last week of

April or in the last week of May will control to

some extent the summer fruit drop in Langra &

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CONT.

• Application of plant growth substances like NAA@ 25

ppm or 2,4-D @ 10-15 ppm during pea stage of fruit are

helpful in reducing fruit drop.

• Studies on the use of plant growth substances for fruit

retention in mango cv. Dashehri were conducted at pant

nagar. Growth regulators were applied at 3 different

stage to 12 year old trees. NAA@ 40 ppm gave the best

fruit retention when applied at the pre bloom stage. At

the pea stage CCC @ 200 ppm gave the best results

and the marble stage AgNo3 @ 200 ppm gave the best

results.

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CONT.

• 2,4-D (30 ppm) has given good results in controlling fruit drop in var.

Neelum, without having any adverse effect on fruit size or TSS.

• Flower and fruit drop is a problem in many fruit crops. Application of

NAA 10- 50 ppm in mango reduce fruit drop by preventing formation

of abscission layer.

• Early Ripening and Colour Development, Fruits like mango, banana,

papaya ripes after harvest.

• Dipping of fruits in 20-50 ppm Ethrel solution induces golden yellow

colour to fruit induces early maturity.

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CONT.

• NAA @ 20 ppm is sprayed at flowering to increase the fruit

retention. 

• During February 0.5% Urea (5 g/lit.) or 1% Potassium Nitrate

(10g/lit.) may be sprayed to induce flowering, if trees do not flower

by that time.

• Spraying of 2% KNO3 at mustard size will increase the fruit set and

retention of fruits.

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ALTERNATE BEARING

• To control alternate bearing using an ethylene releasing compound,

ethepon inducing flowers several year.

• In mango, application of ethepon 200 ppm coupled with 0.1 per

cent urea was found effective in inducing regular flowering over the

year.

• Five sprays all recommended to be made beginning from middle of

September at monthly interval.

• Proper cultural practices like addition of fertilizers and control of

diseases and insect pests may be adopted to regulate growth and

bearing

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• Regular bearing varieties viz. Dashehari and Amrapalli may be

grown. Deblossoming of the panicles with NAA @ 200ppm. (20 g.

/100 l. water) during ‘on’ year may help to regulate the bearing.

Application of paclobutrazol

• Growth retardant called ‘Paclobutrazol’ is used to induce flowering

in mango.

• Application of Paclobutrazol @ 10 g a.i. for non-bearing trees during

first fortnight of September will induce flowering and fruitset yield

during off years

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APPLICATION OF PACLOBUTRAZOL

• Spraying of 1000 ppm

Paclobutrazol (10-60 gm/tree),

prior to FBD, during the first

week of October reduced

malformation, increased

number of healthy flowers and

increased the yield.

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PARTHENOARPY

• Induce parthenocarpy through the application of NAA@ 10 ppm at

anthesis followed by a combination of NAA @ 10 ppm & GA3 @

250 ppm at fortnightly intervals. Such fruit could not attain normal

size rather remained smaller in size, but were superior in taste as

compared to normal seeded fruit.

• Natural parthenocarpy is not reported to occur in mango. However,

exogenous applications of N6 – Banzyladenine (250 ppm) at

fortnightly intervals, resulted in the production of seedless fruits in

Dashehiri

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SMUDGING

• Induction of flowering in mango through smudging is an age old

practice in the Philippines.

• Some attribute the flowering to heat whereas the others hold CO2

responsible for this. However, these have not been found to be

helpful in India.

• In recent years, Ethrel has also been tried to induce flowering in

mango during the off year and some success has also been claimed

in this regard.

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RIPENING

• Fully developed green Langra and Dusehari mangoes can be artificially ripened by treating with 800 ppm @ 1.5 g/kg of fruit. The time for ripening reduces to 4 days as compared to 8 days untreated by conventional method.

• Post harvest treatment with GA3 at 200 ppm has been found highly effective in retarding ripening of Mallika, Alphonso and Kesar mangoes.

• GA3 treatment retarded the total loss in weight, chlorophyll and ascorbic acid content and reduced amylase and peroxidase activity during ripening.

• Similarly pre harvest application of GA3 also influenced the post harvest ripening behavior of mango. The post harvest dipping treatment of Alphonso mango with cycocel, alar at 500 ppm significantly retarded ripening process.

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