Unit – 7
Cultivation practices of Pomegranates
Pomegranate (Punica granatum)
Introduction
There is no other fruit crop that has high medicinal value compared to that of
pomegranate. The pomegranate plant comes in either a tree or a shrub. It is usually grown for its large fruit, but there are some dwarf cultivars used primarily for landscaping or bonsai trees.
Composition and uses
It is a rich source of Iron, Vitamin and minerals. Fruits are consumed fresh and also making juice, wine, squash etc. It possess medicinal value and used in increasing blood level during Leprosy. Its rind helps in controlling dysentery.
Origin and distribution
The pomegranate is native to Iran. The most important growing regions are Egypt,
China, Afghanistan, Pakistan, Bangladesh, Iran, Iraq, India, Burma and Saudi Arabia.
Variety
1. Paper Shell
It is round, medium to large; pale-yellow blushed with pink; with very thin
rind, fleshy, reddish or pink, sweet, very juicy pulp and soft seeds. Bears
heavily.
2. Bedana
It is medium to large, with brownish or whitish rind, pulp pinkish-white, sweet,
seeds soft. '
3. Kandhari
It is large, deep-red, with deep-pink or blood-red, subacid pulp and hard seeds.
4. Dholka
It is large, yellow-red, with patches of dark-pink and purple at base, or all-over
greenish-white; thick rind, fleshy, purplish-white or white, sweet, pulp; hard
seeds. The plant is evergreen and non-suckering.
5. Muscat Red
It is small to medium, with thin or fairly thick rind, fleshy, juicy, medium-
sweet pulp, and soft or medium-hard seeds. The plant is a moderately prolific
bearer.
6. Kabul
It is large, with dark-red and pale-yellow rind; fleshy, dark-red, sweet, slightly
bitter pulp.
Climate and soil
It can be cultivated between altitudes of 500-1850 masl. It requires temperature about 13-350°C but ideal temperature is 180°C which provides quality fruits having high juice level. It requires about 500-600mm annual rainfall. It can tolerate drought and frost condition. High humidity during fruiting stage decreases the quality of fruits. Loamy to sandy loam is best soil for its cultivation. Soil pH should be 5.5-7.5. The soil should have proper drainage facility. It can be cultivated in alkaline soil also.
Propagation
Pomegranate seeds germinate readily. Selected cultivars are usually reproduced by means of hardwood cuttings 10 to 20 in (25-50 cm) long. The cuttings are set in beds
with 1 or 2 buds above the soil for 1 year, and then transplanted to the field. Grafting
has never been successful but branches may be air-layered and suckers from a parent plant can be taken up and transplanted.
Planting
In a well prepared land sapling should be planted in a pit size of 60 cm x 60cm x 60 cm. The spacing should be maintained about 4-5m. It can be planted by adopting square or contour system before onset of monsoon or end of monsoon.
Irrigation
It requires more irrigation during its early years of planting. Irrigation is more essential during flowering and fruiting stage. Less soil moisture may cause flower and fruit dropand cracking of fruits. Generally, irrigation is done at 15-20 days interval depending upon the soil moisture condition. Heavy irrigation may cause less flowering.
Manure and fertilizer
The recommended dose of manure and fertilizer are:
Pomegranate is a hardy plant but it responds well to manure and fertilizers.
About 20 - 50 kg FYM/tree for bearing trees/year along with 400g N: 200g P:
200g K/tree.
For pre-bearing plants full dose of P , K and 3/4th of N should be given at the
time of bahar (flower induction), remaining 1/4th of N given at 1.5 months after fruit setting.
At the age of 8-10 years this dose should be doubled.
Training and pruning
The diseased, dried, unwanted and overlapped branches are removed. The suckers are also removed. The main trunk should be cut at the height of 1m which helps to develop lateral branches. 3-5 lateral branches are kept.
Intercropping
Pomegranate have short juvenile period. Plants are also planted closely and remain bushy and spreading in nature, hence, no intercrop should be grown. When planting distance is more than 4m x 4m then intercrops can be grown for the first two to three years. Growing of vegetables and pulses should be preferred over rabi crops and fodder crops. If wheat is to be grown prepare separate irrigation system for irrigation to pomegranate plants during March-April.
Intercultural operations
Pomegranate is closely planted; hence use of a tractor to inter-cultivate is not desirable.
Weeds should be manually removed by hoeing the basins once in December at the
time of fertilization and then again in May. The left out places may have some
weeds/grass growing. If so, spray Gramoxone (paraquat) @ 6 ml/l of water during july. Keep the nozzle of spray close to the weed growth to avoid drift of the chemical.
Flowering and pollination
Pomegranate bears three types of flowers i.e. pure male with rudimentary ovary;
hermaphrodite with medium style and hermaphrodite with well-developed style. The percentage of these flowers varies from cultivar to cultivar. There is no shortage of
pollen and pollinating agents. Sufficient number of fruits set from hermaphrodite (pin) flowers. Pollen is available at noon and stigma remains receptive for 2-3 days. Both cross and self-pollination take place.
Fruit set
This deciduous bush typically grows from 12 to 20 feet tall and nearly the same in
spread. Some patience is required when growing a pomegranate tree, as it takes five to seven months for fruit to become mature and the tree itself needs 2-3 years before it bears more than a couple of fruits. In addition, the pomegranate tree loses its vigor after 15 years or so, although some cultivars may live hundreds of years.
Fruit growth and development
Following fruit set, the colour of the sepals skin in the developing fruit changes
continuously from the prominent orange-red to green. In later stages of fruit
maturation, the color will change again until it reaches its final characteristic color as the fruit ripens. The external color ranges from yellow, green, or pink overlain with pink to deep red or indigo to fully red, pink or deep purple cover, depending on the variety and stage of ripening. The fruit ripens 5 to 8 months after fruit set, depending on the variety.
Bearing habits
Some pomegranates have a bearing habit with alternating high and low yields. A heavy crop of fruit tends to deplete carbohydrates and results in a small crop and increased vegetative growth the following year. Pruning after a light crop and before an expected heavy crop should help to reduce alternate bearing. The orientation of branches in space has a marked effect on growth and fruiting. Favouring horizontal branches over
upright ones should result in better growth control and more fruit production.
Insect pest of pomegranate
1. Fruit borer (Virachola isocrates)
It is a serious pest of pomegranate.
Newly hatched caterpillar bore into the fruit and feed on developing seed.
Hole is made by caterpillar which facilitates the entry of pathogen that leads
to fruit rot.
Control:
Collect and destroy infected fruits.
Bagging of fruits is done with butter paper after spraying Dimethoide@ 0.05%.
2. Fruit sucking moth (Othreis spp.)
Moth punctures the fruits and sucks the juice.
Pathogens may enter from puncturing part which cause fruit rot.
Control:
Collect and destroy the infected fruits.
Harvest matured fruits earlier.
Generate smoke in an orchard during night.
Keep poison bait (Malathion 50 EC @ 2 ml + molasses 200 g + 2 litres
of water).
3. Thrips (Scirtothrips dorsalis Hood)
They suck the cell sap from the tender parts of leaves, flowers and fruits which cause yellowing of leaves, fruit drop.
Flower drop and yield is reduced.
Control:
Adopt clean cultivation.
Spray Dimethoate 30%EC 2-3 ml/l of water or Fipronil 5 SC @ (50 ml
a.i./ha) @ 1 ml/l of water.
Disease of pomegranate
1. Leaf spot
C/O: Fungus
S.N: Cercospora punica
Symptoms:
Light brown to dark spots are seen on the leaves.
In severe infection leaf drop takes place.
Control:
Adopt clean cultivation.
Spray Captan @ 2g/l of water at 10-15 days interval.
2. Fruit Rot:
C/O: Fungus
S.N: Colletotrichum gloeosporioides
Symptoms:
Black spots are seen on the lower part of the fruit.
The spots cover about half portion of the fruit at 7-10 days of infection.
Finally the infected portion of fruit gets rot and the fruit drop takes place.
Control:
Apply Mencozeb @ 2g/l of water at 10-15 days interval.
Apply 2 g Kaucho and 1g Bevistin in 1 lit. of water and spray.
Physiological disorder
1. Fruit Cracking
It is more serious in arid zone. Cracked fruits get affected by fungi and fruits become unfit for consumption. Fruits crack due to wide variation in humidity and soil moisture.
Prolonged drought causes peel hardening and when rain comes or irrigation is applied the arils swells and peel cracks. Cracking can be controlled by supplying irrigation at regular intervals. Planting of wind break around the orchard also help in the reduction of fruit cracking. Spray of borax @ 0.1 to 0.2 percent is found effective in fruit cracking.
2. Internal Break Down of Arils
Blackening or dis-colouration of arils in ripened fruits is a serious malady throughout the pomegranate growing areas. No cause or remedial measure can be suggested at this stage. The fruit should be harvested at ripening stage without keeping it on the tree for more time than required.
Stage of maturity
Pomegranate fruits become ready for harvesting after 4-5 months of fruit set. Fruits are harvested when its colour turns from green to red. It gives metallic sound. The fruits are harvested at full maturity, when rind has developed a typical colour of the respective cultivar. At this stage calyx at the tips dries up.
Harvesting methods
Pomegranate is non climacteric fruit hence should be harvested when fully ripe. Fruits should be harvested with the help of secateurs.
Yield
It yields about 3-4 tons per hectare. Properly managed orchard of 3-4 years gives about 200-250 fruits per plant.
Grading and packaging
Generally pomegranates are graded according to their size, weight and
appearance. Fruits are packed as per their grade. Boxes are used for packaging and fruits are cushioned with paper strips/cut pieces. The fruit is transported to the markets.
For small markets fruits are packed in wooden boxes of 5 to 10 kg size.
Transport and storage
Pomegranates are generally transported by road. Use of shrink films for moisture loss control can be useful. The suitable temperature for cold storage of pomegranate fruits ranges between 5-10°C, with 90-95% relative humidity. Fruits stored at lower temperatures 0-3°C develop chilling injury.