plant growth regulators in mango endnext. introduction plant growth regulators are organic...
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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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