UNIT 1
CHAPTER - 4
GLADIOLUS
Scientific name: Gladiolus spp
Family: Iridaceae
Gladiolus, commonly called ‘Sword Lilly’ or ‘Corn flag’ is one of the most important cut flower crops. Gladiolus is originated in South Africa. The term gladiolus is derived from a Latin word “gladius” meaning “sword”.
Gladiolus flower
In India it is becoming more
popular as a cut flower and for preparation of ‘Bouquets’. As a landscape
plant, it improves the aesthetic look of the garden. This could be grown in
formal or informal beds, as border plant and may be planted in groups also.
Gladiolus is mainly cultivated in Punjab, Haryana, Karnataka, West Bengal,
Andhra Pradesh and Uttar Pradesh.
Varieties
About 30000 varieties are developed in gladiolus. Important varieties are Friendship, White friendship, Dr. Fleming, Peter pears, Agnirekha, Arka Poonam, Arka apsara, Muktha, Archana, Manohar, Arka Gold, Arka Ranjini, Priyadarshini etc.
Climate
Subtropical and temperate climatic conditions are suitable. The crop performs well under a temperature range of 27-30°C. It requires full exposure to sunlight and performs well with long day conditions of 12 to 14 hours of photoperiod. Low winter temperature below 10oC can cause a loss in quality (blindness)
Soil
Ø
Well drained sandy loam soil rich in organic matter with pH of 5.5
– 6.5 is suitable.
Ø
It can be grown both in plains and hilly regions.
Ø
Highly acidic and alkaline soils should be avoided.
Ø
Clay soil is not suitable for gladiolus cultivation.
Ø
This crop requires open sunny locations; minimum 10 hours of
sunlight to overcome blindness. So season should be adjusted or light
substitution should be given.
Ø
The time of planting is important for gladiolus as it affects the post-harvest
life of cut flower. To obtain good
quality flowers, for commercial cut-flower production, late September, October
and November are very suitable.
Ø
Maximum cormel yield was obtained from June planting.
Propagation
Gladiolus can be propagated through
1. Seeds
2. Corms
3. Cormels
4. Tissue culture
Commercial method used is vegetative propagation
through corms
and cormels.
Cormels developing in a Gladiolus corm
Dormancy
Corms and cormels
of gladioli undergo a period of dormancy. Cold storage of corms at 3 to 7°C for
3 months or treatment with Ethrel (1000ppm) or GA3 (100ppm) or Thiourea (500
ppm) is adopted for breaking corm dormancy.
Seed treatment
Before storage,
corms are dipped in fungicide solution (Captan or Thiram 2 g/lit) to control fungal diseases.
Land preparation and planting
Ø
Dig the land 2-3 times about one month before planting.
Ø
Ridges are prepared 20 cm apart and corms are planted on the
ridges at 30 cm distance. (Spacing -
20cm X 30 cm).
Ø Corms are planted at a
depth of 5 cm.
Planting System
Ridges and furrows system is adopted.
Irrigation
Ø
Irrigation depends on soil type and climate.
Ø
Generally irrigation for gladiolus is practiced once in 2-3 days.
Ø
Irrigation should be withheld at least 4-6 weeks before lifting of
corms.
Manuring and fertilizer application
Ø
Around 25 t/ha well rotten FYM can be
applied as basal dose.
Ø
100 kg N, 60 kg P2O5 and 60 kg K2O per hectare is
recommended, of which 50 kg N and entire dose of P2O5 and K2O are applied as basal dose.
Ø
The remaining 50 kg N is given as top-dressing, at 45 days after planting.
Special horticultural
practices
1. Earthing up: is an important
operation and this has to be done at least once at the 3-5 leaf stage. In windy
localities a second earthing up at the 7- leaf stage, when the spike just start
emerging could be followed, so that the plants do not lodge with strong winds.
2. Staking: In case where spikes grow longer or stems are not strong enough
to bear the lodging or mild stroke of wind, they are supported with about 1.5
meters strong stakes. Strings instead of stakes may be used at the time of the
appearance of the spikes. Strings are stretched between the stakes along the
row to provide easy and adequate support.
Plant Protection
Insects Pests
1. Thrips :- These small insects feed on leaves, spikes and florets. Thrips can be controlled by Methyl demeton 25 EC , Acephate 0.05% or dimethoate 30 EC @ 2 ml/lit.
2. Leaf eating caterpillars:- Semilooper and Helicoverpa usually feed on foliage or flowers and can be controlled by neem seed extract 4% or Methyl demeton or Monocrotophos @ 2 ml/lit.
3. Aphids: - They suck sap from tender leaves, emerging spikes and as well as florets. Aphids(winged ones) are vector of cucumber mosaic virus and bean yellow mosaic virus. Spraying with Pongamia oil or Neem oil @ 1% can control the pests. Insecticides like Dimethoate can also be used.
Non - insect pests
1. Mites: - Present in soil and attack corms. They occur in hot season and damage leaves and buds which give a pale appearance. Spraying of Dicofol or Triazophos @ 0.06% or Kelthane 0.025% can control this non insect pest.
2. Nematodes: - Several species of nematodes are known to attack gladiolus. The root knot nematode is common. It can be controlled by hot water treatment at 53 0 C for 30 minutes. Soil fumigation and use of neem cake 1 kg/sq m also control nematodes.
Diseases
1. Fusarium rot: This is the most destructive fungus affecting gladiolus. Yellowing of older leaves and wilting are the symptoms. Use of healthy corms, clean cultivation and treatment of corms with Bavistin before planting are the management measures.
2. Botrytis soft rot: Both leaves and flowers are affected. Small brown or grey spots are developed on one side of leaves initially. Water soaked spots are seen on the petals. Clean cultivation, hot water treatment and chemical treatment with Carbendazim, Indofil M-45 or Kavach @ 0.2% at fortnightly intervals can manage disease.
3. Several viral diseases like cucumber mosaic, tobacco ring spot, tomato ring spot, aster yellow and bean yellow mosaic affect gladiolus. The symptoms are stunted plant growth, chlorosis and mottling of leaves and flower spike distortion and streaking of coloured florets. Plants should be destroyed as soon as the symptoms are detected. Insecticide spray against the vector is an effective method to check the spread of the disease.
Physiological Disorders
Gladiolus is an indicator plant for fluoride pollution because it expresses the effects of fluorine at very low level. Under high fluoride contents the leaf shows scorching and starts drying from tip.
Harvesting stage
Ø
The plant starts flowering
in 2-4 months after planting based on the variety and corm size.
Ø
The entire spike along with
two leaves is cut, when the basal flower bud starts opening (for local market).
Ø
For export or to distant
market spikes are harvested at bud stage when florets at the bottom show
color.
Ø
Spikes should be cut with sharp knives or secateures.
Ø
Immediately after cutting, spikes should be placed in water.
Ø
After harvest of flowers, the plants are
left undisturbed in the field.
Ø When they start yellowing, the plants are uprooted for harvest of corms
and cormels.
Post-Harvest Operations
Vase life
The opening of florets of gladiolus can be
improved by treatment with floral preservatives. Spikes cut at tight bud stage
(when basal florets show colour) can be pulse treated with sucrose plus 8-HQC
(200ppm), for improving vase life. Instead of 8-HQC, Aluminium sulphate is
used.
Grading
Ø
The grading is based on spike
length and number of florets present on them. Besides, the spike should be
straight and strong.
Ø
The florets should not be opened, should be symmetrically arranged
and well-spaced on spike.
Ø
Spikes should be free from pest and diseases.
Ø
Important grades of gladiolus are Fancy, Special, Standard, and
Utility.
Packaging
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The graded spikes are made into bunches of 10 or 12, loosely tied
with rubber band and tightly packed in non-returnable telescopic boxes made of
cardboard.
Ø
The different colors should not be mixed in a bunch.
Ø
Empty tube light boxes can be used for packing for domestic market
(127cm X 22cm X 22cm).
Ø
Each box can accommodate 250- 300 good quality spikes.
Ø
The packing boxes should be presentable and of good quality and
strength to withstand the shocks during transit.
Ø
The vents should be made in the side walls of the boxes to allow
circulation of air.
Ø
The spikes should be held erect to prevent negative geotropic
bending, and stored at 5-6 0 C till packing (pre-cooling).
Ø
The storage period should not exceed preferably for more than 24
hours.
Ø
In each carton, spikes may be wrapped in polythene, butter paper
or wax paper.
Ø
The spikes are transported both by air and surface transport.
Yield
The yield of flower spikes and corms in
gladiolus depends on variety, corm size, planting density and management
practices. Gladiolus planted at a spacing of 20 x 30 cm yields approximately
150,000 marketable spikes per hectare. Additional income can be obtained from
the sale of corms.
Harvesting and storage of
corms
Ø
After cutting spikes, reduce the frequency of irrigation (once in
10 days).
Ø
Six to eight weeks after flowering, lift the corms and cormels.
Ø
Clean them, treat with fungicide as done during planting, store
them in well ventilated cold storage.
Ø The corms are to be
inspected periodically and any disease infected corms should be removed and
burnt.
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