Everything you need to know about growing and harvesting litchi! Learn about: 1. Botany of Litchi 2. Origin of Litchi 3. Climate and Soil 4. Orchard Cultural Practices 5. Propagation Techniques 6. Planting Operation 7. Flowering and Fruiting 8. Training and Pruning 9. Harvesting and Handling 10. Varieties.
Botany of Litchi:
The litchi is an evergreen tree belonging to the family Sapindaceae (Soap berry family) and sub-family Nepheleae. Rambutan (Nephelium lappaceum), Longan (Dimocerpus longan) and Pulasan (Nephelium mutabile) are other members of the sub-family. Rambutan bears fruits of good quality which are considered even superior to those of litchi.
This plant does well on the lower slopes of the Nilgiris. Longan (anshpal), sometimes called ‘Little brother of litchi’ bears edible fruits in which the aril does not separate readily from the seed. It is grown in Southern India, Assam and Bengal. Both can be used as a rootstock for litchi.
The genus Litchi has two species, Litchi philippinenis and Litchi chinensis. The former is a wild plant grown extensively in the Philippines. This species is not of commercial importance except being used as a rootstock.
The litchi (Litchi chinensis Sonn.) trees are medium to large, much branched, round- topped, handsome evergreen tree, reaching up 15 metres or more in height. The plants have alternate, pinnate and leathery leaves, having 5-7 opposite or alternate leaflets. The leaves are glossy green above and greyish green on the under surface. The bark is greyish brown and rough. The litchi plants bear three types of petal-less flowers. The first flowers to open are males.
The inflorescence is a compound raceme developing both from terminal and axillary buds. The first type flowers are the staminate flowers in which the pistil is aborted almost completely. After two to four days, the pistillate hermaphrodite flower appears. These flowers bear fruit. There is a transitional period of two to three days and then the staminate hermaphrodite flowers with united stigmas appear.
These flowers continue for 10 to 14 days. The flowers of different sexes on the panicles do not open simultaneously. The panicles on the same branch flower during the same period but flowers on panicles borne by different branches appear on different days.
So, for effective pollination and fruit set of litchi mixed planting, i.e., growing of several varieties together in an orchard is recommended. Pollination is done by insects, which include the honey bee and flies. The seedless varieties seem to be self or cross sterile, while those with normal seeds are probably self and cross fertile.
Origin of Litchi:
The Litchi, lychee, lici or licy is indigenous to the southern part of China and seems to have reached Eastern India by the year 1800. The cultivation of this fruit has become very popular in South Africa, especially in Natal and the Transvaal. South Africa exports litchi to the U.K. After China and South Africa, India is the next important country for litchi production.
This sub-tropical fruit is very fastidious about its climatic requirements. In India the state of Bihar, especially the Muzaffarpur district, has almost a monopoly of litchi production. A few trees are also found in humid parts on the hill-slopes in the Nilgiris up to a height of about 1,000 metres. In West Bengal, it is planted on a limited scale in wet lands along boundaries of fields. The water here is not stagnant and keeps moving constantly.
It occupies 1.4% of the total area and 0.8% of total production of fruits. The area and production of litchi is reported to be 0.58 lakh ha and 3.56 lakh tonnes. Bihar has the maximum area (27.7 lakh ha) with production of 221.7 lakh tonnes.
The litchi, litchi chinensis, belongs to the botanical family Sapindaceae, to which also belongs the soap-nut tree, found growing commonly in the lower Himalayas. The litchi is a delicious, juicy fruit, which comes to the market in May-June in North India, when no other fresh fruit is available except a few plums etc. Local mangoes are not ready at this time and litchi fetches a fancy price.
This sub-tropical fruit cannot tolerate frost in winter and dry heat in summer. It is advisable to plant suitable wind break trees around the boundary of litchi plantation. Its cultivation in the Indo-Gangetic plain is almost entirely limited by the presence of hot desiccating winds in summer.
It is not fastidious about its soil requirements and can stand almost any soil, but it makes best growth in deep loam. It requires good drainage of soil. In Bihar the litchi soils have high lime content. In the ancient Moghul garden at Pinjore on the way to Shimla, there is an excellent plantation of litchi at the foot of the Himalayas.
Litchi can be propagated vegetatively quite easily, but these plants do not have as good a root-system as the seedlings, and their survival after transplanting is a problem. The most widely established method of propagation in India is ground-layering. It is somewhat slow method and the plants are expensive, but very successful.
The handsome litchi tree with its shiny evergreen leaves is slow-growing, but finally it becomes quite large. Under normal conditions, it should be planted 10 metres apart. Where hot winds are serious, the trees should be planted only 8 metres apart. The planting distance in different parts of the world varies from 6 to 16 metres. The pits should be heavily manured before planting in order to hasten the growth of the young trees.
An interesting feature of the litchi plant is the symbiotic growth of mycorrhizal fungi on the roots of the trees. Just as bacteria live on the roots of the leguminous plants like the Egyptian clover and fix nitrogen from the air present in the soil, these fungi perform the same function in litchi. These fungi form nodules on the roots of litchi. The trees and the fungus live together to the benefit of each other.
To ensure that the new plants carry the fungi, they should be propagated or potted in soil taken from under old litchi trees. The young litchi plants are very sensitive to frost, especially when actively growing. They must be protected with a covering of thatch for several years in places where there is danger of frost. Litchi is a shallow-rooted tree and should not be given deep tillage. Use of a mulch or chemical weed control without tillage is likely to prove beneficial for litchi.
Climate and Soil Required for Growing Litchi:
Litchi, being a subtropical fruit, thrives best under moist subtropical climate. In China, where the litchi originated, the summer months are hot and humid and the winter months are cool and dry. The litchi usually likes low elevation but can be grown up to an altitude of 800 metres with varying degree of success. The site selected for litchi should be free from frost, have high humidity and abundant soil moisture.
Frost in winter and dry heat in summer are limiting factors for its successful cultivation. Under these conditions tree makes poor growth and fruit cracking is a very serious problem. The young trees require protection against frost and hot desiccating winds for several years till they are firmly established. The temperature during summer should be less than 41°C and during winter between 1.1°C to 4.4°C for successful litchi cultivation.
In Punjab and Haryana, litchi does well in sub-montane tract of Gurdaspur, Hoshiarpur, SAS Nagar, Ropar and Ambala. The litchi can also be grown in the districts of Amritsar, Jalandhar, Ludhiana and Patiala under protected conditions. In these areas summers are quite hot to encourage vegetative growth of plants and winters are cool enough to provide 200-300 hours of chilling temperatures to facilitate bud differentiation in litchi. Quite frequently, summer temperature rises above 40°C during the period of fruit growth and development. This is favourable for sun burning and cracking of fruits to varying intensities in all the cultivars.
In South India, litchi grows only on hill slopes upto an elevation of 1067 metres which are cooler than the plains. In Western Uttar Pradesh, where annual rainfall is not more than 89 cm, litchi grows successfully with artificial irrigation. Prolonged rain is not desirable, especially at the time of flowering, when it interferes with pollination.
Litchi grows best in a deep, fertile, well-drained loamy soil rich in organic matter. It is must that the soils do not have a hard pan within 2.5 metres of the surface. Litchi seems to do well under slightly acidic conditions. In acidic soils the roots are covered with tubercles containing mycorrhizal fungi which grow on the roots of the litchi to the mutual benefit of the fungus and the plant.
Preferably, the soil pH should be 7.5 to 8.0. In high pH and saline soils, litchi is difficult to establish and flourish. The litchi roots can stand immersion for a considerable length of time provided that the water is flowing. In no way it can stand in stagnant water as it causes root decay. The soils with adequate sub-surface drainage are suitable even if they remain wet for long periods.
Orchard Cultural Practices for Growing Litchi:
i. Irrigation:
Adequate soil moisture is considered essential for successful litchi cultivation. In areas, where annual rainfall is more than 125 cm and is well distributed throughout the year, litchi can be grown without irrigation. The young plants neither establish well nor do they make optimum growth if there is shortage of water. Copious and frequent watering is essential for the bearing litchi trees.
Litchi should be carefully irrigated at all stages of development. Their irrigational needs are especially more in summer. The young plants need irrigations twice a week during April- June. In winter, weekly irrigation would be sufficient.
Adequate frequent watering is essential for the bearing litchi trees. The development of litchi fruits takes place during March to May when the temperature starts rising in the plains of India and the atmospheric humidity remains very low. Evapo-transpiration consequently rises considerably.
If the litchi orchard is not frequently irrigated during the spring and summer months, there is chance of severe fruit drop. The fruit which remain, do not develop fully, often split and become unfit for consumption.
At fruit set, irrigation is given at three weeks’ interval which is reduced as the atmospheric temperature increases. During fruit development period i.e. from the second week of May to the end of June, irrigation should be given twice a week. Irrigating litchi tree twice a week during this period reduces cracking of fruits to a great extent and helps in proper size development.
After the withdrawal of monsoon bearing orchards should be irrigated at the end of November or first week of December to protect them from frost injury. Later on irrigation during winter should be applied depending upon rain and soil moisture conditions. Irrigation of young trees should be done by the basin system. As the trees grow, the basin should be gradually enlarged.
When the trees are fully grown and have occupied the entire soil with their root-system, then the flooding system of irrigation should be introduced.
ii. Intercropping:
The litchi is a slow growing tree and takes at least six years to come into bearing. During the early years, the vacant space in between the trees may be utilized profitably by growing intercrops. The choice of intercrops depends upon the climate and soil and also on the marketing facilities. The vegetables may be grown near the cities, while leguminous crops like pulses, guara and senji may be grown at places away from the market.
During karif season, vegetables like pumpkin, ridge gourd, bitter gourd, cucumber and leguminous crops such as moong, mash, moth and cowpeas may be grown. Guara may also be grown as a green manure crop which will protect the young litchi plants against hot desiccating winds in addition to enriching the soil. In winter season, radish, carrot, turnip, cauliflower, peas and gram may be grown as intercrops. Senji is also grown as fodder or as a green manure crop.
Beside vegetables and pulses, some quick-growing fruit plants can be grown in the early years. Phalsa and papaya are the excellent intercrops during the initial years. The phalsa bushes can be kept low by severe annual pruning and do not crowd around the litchi plants.
Papaya because of their upright growth, do well as an intercrop. The most productive period of the papaya plants would be over by the time the litchi trees comes into bearing and it can then be removed from the orchard. Peach, plum and kinnow are also good intercrops. The intercrops should be manured separately and protected from the attack of insect pests and diseases.
iii. Weed Control:
In the litchi orchard, cultivation should be kept to the minimum. The main objectives of tilling the orchard should be weed control or the mixing of manures and fertilizers with the soil. The litchi is a shallow-rooted plant and deep ploughing of the orchard soil should be avoided as it damages the root-system. Most of the persistent weeds in litchi orchards could be controlled by the application of post-emergence herbicides like glyphosate and paraquat.
Diuron @ 5 kg/ ha as pre-emergence herbicide can effectively check the weed flora in litchi plantation. Post- emergence herbicide glyphosate @ 1 – 2 a.i l/ha or paraquat @ 0.6 – 1.2 a.i l/ha are very useful for weed control in litchi orchard. Mulching the orchard with black polythene is very useful practice which preserves the soil moisture and controls the weed population.
iv. Mulching:
The moisture of the soil can be preserved by providing mulch over it. The use of mulch enhances the rate of penetration of rain-water or irrigation into the soil. Apart from this, it also checks the growth of weeds, thus eliminating the competition between the weeds and the fruit trees. The use of mulch in young litchi plants encourages the development of a better root system than in the case of the plants growing in a bare soil. The farmyard manure, compost or straw can be used as mulch.
The farmyard manure and compost are the excellent mulch material, because they enrich the soil in addition to conserve soil moisture. When straw is spread over the soil as mulch material, an additional dose of 2.5 – 3.5 kg of calcium ammonium nitrate per quintal of dry straw is given to hasten the rotting of straw.
The litchi plants will suffer from nitrogen starvation if additional dose of nitrogen is not given along with the straw mulch. Besides, cutting down of tall weeds growing in the orchard and leaving them spread over the orchard soil also provides good mulch. Polyethylene preferably black polythene can be used as best mulch material to maintain high moisture level and to control the growth of weeds.
v. Manuring and Fertilization:
The special attention should be given to maintain the optimum levels of NPK in the orchard soil. When nitrogen is present in the soil in sufficient quantities, the plants make luxuriant growth, have dark-green leaves and produce high yield. The trees growing under nitrogen deficient conditions remain stunted. The leaflets are rough in texture with curling margins.
The yellowing first appears in the old leaves and when the deficiency continues, the young leaves may also become yellow. When phosphorus is deficient the leaflets become abnormally large and dark green. The texture of the leaves is little rough and dark brown scorched areas appear in the old leaves.
The deficiency of potassium causes considerable stunting of the plants. The leaves are small and soft in texture. The scorching of leaf margin starts from the tip and progress gradually towards the base of a leaflet.
Propagation Techniques for Litchi:
Litchi can be propagated from seed or through vegetative means.
i. Seed Propagation:
The trees raised from seeds are very slow to come into bearing and may take ten years or even much longer time to come to bearing. The seedling trees do not produce true-to-type and often yield fruits of inferior quality. The litchi seed also loses its viability within 4-5 days of its extraction from the fruit.
However, seed propagation may be followed for raising rootstock. In such case, the seeds should not be allowed to become dry but should be sown fresh just after extraction. The seeds may be kept viable for about two months by leaving them in the fruits or keeping them in moist packing material. So, considering these problems, litchi is usually propagated vegetatively.
ii. Vegetative Propagation:
Litchi can be propagated through cutting, layering, budding and grafting. Layering is the common method of propagating litchi in most parts of the world. Air (gootee) layering is used commercially for raising litchi plants. This method being less tedious than inarching and due to high percentage of success is adopted by the nurserymen throughout of India for litchi propagation. The plants prepared by this method are ready for sale within a year and quarter, the date of layering.
A terminal branch, 45-60 cm long and 1.0-1.25 cm thick is selected. A 4 cm wide ring of bark is removed with a sharp knife. Place wet moss or roots of water hyacinth on the exposed portion and wrap it with polythene sheet. The ends of wrapped polythene sheet should be tied tightly. The rooting starts after about 4 weeks. However, the gootee should be severed from the mother tree, remove the polythene sheet and immediately plant the gootee in a nursery bed.
Although, layering in litchi can be done in February-March and July to October, yet the period from middle of August to September is the best for this operation.
Preparation of Nursery Beds:
The nursery beds should be prepared under partial shade- For this, raising the janter in between the nursery beds is quite useful. But care should be taken that jantar rows do not compete with the growth of nearby plants. So, root pruning of jantar plants which are near the litchi row is very necessary.
To the soil where the nursery beds are to be prepared should be added large quantity of organic matter. It is generally recommended that upper 22.5 cm soil should be added with 50 per cent of farmyard manure.
Planting of Layers:
After two or three months of layering, when adequate root system has developed, the layers are separated from the parent plants. Care should be taken that there is proper balance of the top with the root system. If need be, excess branches and leaves should be removed.
The roots of litchi in the beginning are very tender and break away very easily. The rooted layers should, therefore, be very carefully planted in the nursery. These layers in the nursery beds are planted in the rows which are 45-60 cm apart.
The plant to plant distance in the rows is kept 20 to 25 cm. After planting, the layers should be irrigated immediately. The subsequent irrigation should be given at week’s interval. The interval during irrigations can be decreased or increased according to the need of the plants.
Only thing which is kept in mind is that the soil remains in wet condition. The dry condition decreases the growth of the nursery plants considerably. Frost injury is very common in young litchi plants. So, these plants are protected by making thatches of sarkanda on the beds.
The layers after separating from the parent plants can be planted in the polythene bags. The bags should be 22.5 cm wide and about 20-25 cm in length. These are filled with soil and farmyard manure mixed in fifty, fifty ratio. This planting of layers in polythene bags helps in better transportation and thus enhances the success of litchi plants in the fields. Nursery plants of litchi also need some fertilization for its better growth. For this, the light dressing of nitrogenous fertilizers like calcium ammonium nitrate or ammonium sulphate or urea after 2- 3 weeks interval should be given.
Cutting, Budding and Grafting:
Soft wood cuttings may also be made to root with bottom heat and carefully controlled condition. However, soft-wood cuttings do not root well even with the use of growth regulators.
Budding and grafting have also been tried in many countries but the percentage of success with these methods has been very low, ranging between 10-20 per cent only. A method of splice grafting was developed in South Africa with considerable success. Propagation of litchi by inarching has also been tried by the Chinese. It is very tedious and time consuming method and takes several months before an inarched plant is severed from the mother plant. Longan as a rootstock gives quick growth but the bearing is uncertain.
Manuring and Irrigation:
Manuring and irrigation are the two most important considerations in the upkeep of a litchi orchard. In Bihar, generally no irrigation is given to bearing trees because of sufficient retention of moisture in the soil and high atmospheric humidity during the fruiting season. However, in other areas regular irrigation from February to June is necessary. The Chinese apply 250 kg of night soil per tree. In India litchi is grown on fertile soils and manuring is generally neglected, but an application of 10 to 25 kg of farmyard manure per annum per tree depending upon its age is recommended.
Apart from nitrogen, litchi also definitely requires potash and phosphorus. In general 6 to 8 year old bearing litchi plants require an application of 600 g N, 200 g P and 600 g K. The FYM, super phosphate and muriate of potash should be applied in autumn. Nitrogenous fertilizers should be divided into two equal parts and applied once in mid-February and again after harvest of fruit.
The deficiency of zinc is also experienced. It seems to turn the leaves bronze-coloured. It can be corrected by spraying 4 kg of zinc sulphate and 2 kg of hydrated lime dissolved in 500 litres of water. The evergreen litchi plant requires hardly any pruning. The bunches of fruit are harvested along with a part of the shoot. This promotes enough growth of the shoots for fruiting in the following year.
Vegetatively-propagated litchi trees start bearing after six years. Since the tree is slow-growing, the yield continues to increase for 20 years. The litchi fruit is covered with a thin hard skin, which is covered with sharply-pointed tubercles. The fruit is harvested for distant markets when its colour begins to turn pinkish and the tubercles become flattened.
For effective pollination and fruit set of litchi, planting of several cultivars in an orchard is suggested. It has been observed that if new flushes appear in autumn due to late rain, these shoots usually fail to flower.
Fruit drop in litchi usually occurs after fruit set and continues till maturity. Exogenous applications of NAA (5 to 15 ppm), 2, 4 D (10 to 20 ppm) or 0.5 to 1% ZnSo4 mixed with hydrated lime two to three times at weekly intervals considerably reduces fruit drop of litchi.
Fruit cracking in litchi usually occurs due to sharp fluctuation in the day and night temperature coupled with heavy irrigation or rain after dry spell. It can be minimized by the application of 2, 4-D (10 ppm), GA (20 ppm) and Boron 0.4 per cent. Spraying 50 ppm GA, 30 days before harvest at aril development stage enhances fruit growth and also improves fruit quality.
Litchi fruits are graded on the basis of colour, size and blemish. Cassia leaves as packaging material are effective in reducing PLW, spoilage and retaining fruit colour and quality.
Treatment of litchi fruits with 500 ppm KMS at pH of 2 is effective in reducing spoilage and retaining the skin colour at ambient conditions. Further, dipping of fruits in ethrel (250 ppm) markedly improves the fruit colour and fruit ripening is accelerated by 24 to 30 hours.
The fruit does not last more than a few days. It can be kept successfully in cold storage for three months at a temperature ranging from 30°F to 45°F. The Chinese also store it in salt solution inside bamboo stems. In China, the litchi is dried along with the skin. The dried flesh and the seed rattle inside the hard shell and the product is called litchi-nuts. Chinese all over the world are fond of these. In India litchi is not dried, but canning has been started.
Litchi does not suffer from any serious pest or disease in India. Protection from birds is the most serious problem. In vigorous growing young trees, the leaves may become thick and curl up due to an attack of a mite (Eriophyes sp). Apart from other insecticides 0.04% Dimethoate spray can control it. The bark-eating caterpillar (Indarbela sp.) and a scale (Parlatoria pseudopyri) have also been reported. In U.P, the caterpillar, Lymantria mathura which is a pest of mango, has been observed to damage litchi.
A type of the litchi which is more cold-hardy and found in the mountains belongs to the same species, L. chinensis. A few other minor fruits similar to litchi are also found in India. The longan or ‘ashphal’, Euphoria longana is indigenous to the Western Ghats and grows wild at elevations up to 1,600 metres.
Planting Operations for Litchi:
Planting:
Plantation of litchi in spring season has not proved to be a desirable practice because of the high rate of mortality during the hot dry spell of May-June. Litchi should be planted towards the end of the rainy season. During the rainy-season, the temperature in Northern plains becomes moderate and the atmosphere has high humidity. Considering this, litchi should be planted in September-October.
Litchi trees are usually planted 7.5 – 9.0 metres apart both ways i.e. in rows and between plants in a row, thus accommodating 180 – 123 plants per ha. The distance may be reduced to 8 metres when the climate is comparatively dry and the soil is not so fertile.
The success of an orchard depends upon the selection of a plant from the nursery. One should always go in for a healthy and true-to-type plant of a recommended variety. Two year old plants should be planted in the field. By doing so, the field mortality is considerably reduced. Preferably, the young litchi plants should be planted in the nursery and transplanted when they have attained good size.
Before planting, pits of one metre in diameter and one metre deep should be dug a few weeks before the actual planting. The pits are then allowed to remain open for a few days and then filled with top soil mixed with manures and fertilizer at the rate of 20-25 kg farmyard manure, 2 kg of bone meal and 300 g of muriate of potash.
If available, a basket of soil from litchi orchard which contains mycorrhizal fungi should be added to this mixture. The pits are then watered so that the soil settles down. At the planting time a small hole is made at the centre of the refilled pit and the desired plant is planted with the help of planting board. Water should be applied immediately after planting.
Planting of Windbreak:
Hot and desiccating winds in summer and cold winds in winter adversely affect the growth of litchi. The young litchi plants should be protected against these adverse conditions which can cause the uprooting of trees and drop of flowers and fruits. So, two to three years before the litchi trees are planted in the orchard, a windbreak should be planted at the orchard boundary. The windbreak should be at a right angle to the direction of the prevailing winds. A row of tall-growing trees such as jamun, seedling mango, eucalyptus, arjun and simbal alternating with low-headed trees, such as mulberry, ber and neem should be planted.
Protection of Young Plants:
The irrigated sub-montane areas of the Punjab and Haryana are ideally suitable for litchi cultivation. In spite of its being well suited to these areas, there is no headway in area under litchi. This is mainly because of its being a delicate plant which is subjected to high rate of mortality in the initial years due to frost and hot summer winds. After planting, the young litchi plants need protection against winter frost and summer hot winds (loo) up to four-five years.
This can be done by covering the plants with farm-waste materials like sarkanda, rice straw (parali), maize stalks, sugarcane trash, etc. Growing of Jantar (dhaincha) around the young litchi plants also provides good protection in summer and winter. The Jantar seed should be sown around the plant in the basin in the middle of February.
It grows sufficiently by the middle of April to provide shade to the plants. The tops of the Jantar can be tied in winter to act as protection against frost. The open spaces in Jantar can be plugged with locally available straw. Root pruning of Jantar plants is necessary to avoid competition with litchi roots. It should be done three to four times in a year.
Besides, a few weeks after planting 50 g of CAN (calcium ammonium nitrate) per plant should be added to the basins, leaving a width of about 15 cm around the stem. A light irrigation is given after mixing the fertilizer with the soil.
This dose of the fertilizer should be repeated every two months. This would help the young plants to make quick and vigorous growth. The diseased, dried or dead portions of a branch, if any, should be removed. The branches which tend to grow into the centre of the tree and crowds or crosses the framework branches may also be removed.
Flowering and Fruiting:
In North India, the flowering takes place in February. Opening of flowers starts in second or third week of March. Flowering period ranged from 26 to 35 days in different varieties. In Eastern India, the emergence of flower panicles starts during the second week of March and continues upto second week of April in different cultivars. The total duration of flowering in different varieties ranges from 25 to 40 days. The cultivar Shahi is early to flower followed by Rose Scented, Purbi and Bedana.
In litchi fruit, seeds develop initially at a high rate, followed by membranous mesocarp and aril which grow very fast towards the later stage of fruit development. In litchi, from fertilization upto the second week of May is the period of active seed growth and marked by a complete lack of flesh growth.
The increase in fruit diameter during this period is mainly due to the increase in seed diameters. The flesh growth commences from May 14 and increased rapidly upto the harvesting date. The period between the second week of May and first week of June is critical for fruit cracking.
The fruit of litchi is a one-seeded nuts, usually develop in bunches. The fruits tend to be 3-5 cm in diameter and usually oval in shape. The fruits have a thin leathery shell (pericarp) which turns pinkish red when the fruit is ripe. The aril or edible portion which separates easily, lies under the pericarp and completely surrounds the seed. The pulp is translucent, pearly white and soft in texture.
Training and Pruning of Litchi:
Training of litchi plants is done according to modified leader system. Training of plants should be completed upto fourth year of planting.
To give proper shape to the litchi plant, little pruning is often necessary after planting. Once the desired shape is achieved, no pruning is usually necessary, except the removal of dead, diseased and crisscrossed branches. Litchi flower are borne mostly on current year’s growth and old shoot rarely produces flowers. So, to promote new growth, snipping of old branches is desirable.
However, this is done indirectly when a part of the shoot bearing the cluster, the fruit is removed during harvesting. If litchi tree makes too much vegetative growth, both root and shoot pruning may be done. But, heavy pruning causes profuse vegetative growth which takes place at the expense of flowering and fruiting. When the trees become too old and produce fruits of small size, heavy pruning may be done.
Fruit Drop:
Maximum fruit drop occurred during second and third week after fruit set. Seedless Late and Calcutta cultivars are less prone to fruit drop than Dehradun and Muzzafarpur. Apart from the competition among fruits for water and nutrients and other physiological causes, strong wind significantly affects drop. Irrigation to bearing litchi trees twice a week from April onwards and good windbreak minimize fruit drop to a great extent.
Foliar spray with zinc sulphate at 0.5,1 and 1.5 per cent considerably increased the zinc content of the leaves and affectively reduced fruit drop in Dehradun cultivar. Higher level of zinc in the leaves might increase the endogenous production of auxins and thereby reduce the fruit drop.
Similarly, NAA and 2, 4-D at 15 ppm in combination with 1 per cent zinc sulphate resulted in more fruit retention till harvest. Foliar spray of NAA @ 40-50 ppm at pea stage and again 3 weeks later promote fruit set and reduce fruit drop.
Harvesting and Handling of Litchi:
Harvesting:
Layered litchi begins bearing fruit when they are about six years of age. The yield goes on increasing every year till the trees are 20 to 30 years old. Early varieties of litchi like Dehradun start ripening in early June, whereas the mid-season and late varieties ripen in the second fortnight of June. The fruit colour changes from greenish to attractive red or pink. Litchi is a non-climacteric fruit usually do not improve in quality after harvest. So the fruits should be allowed to ripen properly on the tree.
For the local market the fruits should be picked at complete ripening stage. However, when the fruits are to be shipped to a distant market, they should be harvested when they are still hard-ripe or have just turned pinkish and the sharply pointed tubercles on the skin have become flattened. The maturity of the fruit for harvesting is judged from the tubercles on it. When the fruit is mature, the tubercles become somewhat flattened and the epicarp becomes smooth.
The litchi fruit is picked in whole clusters with a portion of the leafy stalk attached to each of them. In this way, the fruit does not wilt soon after harvest. The fruit clusters are spot picked several times as they do not ripen on the tree at the same time.
The harvested fruits should be kept in shade because atmospheric temperature is very high at harvesting time. If allowed to remain exposed to the sun, the fruits lose their freshness, become dull in colour and deteriorate in quality.
Grading and Packing:
Litchi fruits should be graded and then packed in mulberry baskets of suitable size. Soft dry grass or banana leaves should be placed in the baskets before litchi clusters are piled up. The clusters should not be packed too deep or too high as the bottom fruit get crushed. The fruit clusters are covered with some more grass or banana leaves and a piece of moist gunny bags should be wrapped around the basket and tied securely.
Marketing:
A full grown litchi tree of different varieties bears about 80 to 150 kg of fruit. The average yield per adult tree is 4000 to 5000 fruits. After the litchi trees come into bearing, the yield goes on increasing till the trees are 30 years old.
With proper care and management and under suitable environmental conditions, a litchi tree may continue bearing economic crop for over 100 years of age. Litchi is a highly perishable fruit; its marketing should be done as early as possible. During transit, care should be taken to avoid crushing of fruit and damage of the skin.
Storage:
The bulk of the fruit is consumed in the fresh form. The fruit does not keep for more than a few days at room temperature. It loses its bright red colour and turns brown within 2-3 days after harvest. The availability of litchi can be prolonged by keeping the fruits in the cold storage. The most important post-harvest need of litchi is the retention of fruit colour and quality for longer period so that the marketing is phased out to avoid the glut and ensure better premium to the growers.
The shelf life of litchi fruits can be enhanced up to 35 days in cv. Seedless late by storing them in perforated polythene bags of 100 gauge thicknesses in the commercial cold storage (0-3.3°C and RH 85-90 per cent) after treating with 6 per cent wax-emulsion.
The fruits of litchi cv. Bombai packed in perforated polyethylene bags can stored for 18 days at 4°C. A storage temperature of 5-7°C further minimise the losses of litchi fruits. It is reported that litchi fruits of cv. Rose Scented treated with hot water at 55°C and 10 per cent oxalic acid for 15 min. stored well upto 18 days under cold storage condition (temp. 5°C and 85 ± 5% RH).
Varieties of Litchi:
While selecting litchi varieties for planting in an orchard, a few points should be kept in mind. The fruits of the variety should be bright red and the average fruit diameter should not be less than 4 cm. The fruits should not be prone to splitting. The customers prefer fruits which have smaller seeds and pleasant taste. In Bihar, which has the largest area under litchi in India, the important varieties are Shahi, China, Deshi, Dehra Rose, Purbi, Bedana, Mclean, Swarna Roopa and Muzzafarpur.
The varieties grown in Uttarakhand and Uttar Pradesh are Seedless Early, Seedless Late, Early Large Red, Late Large Red, Calcutta, Dehradun, Rose Scented, Khatti and Gulabi. The varieties recommended for growing in the Punjab and Haryana are Saharanpur, Dehradun, Calcutta, Muzzafarpur, Seedless Late and Rose Scented. In West Bengal, the varieties grown are Muzzafarpur, China, Deshi, Purbi, Elachi Early, Elachi Late, Bombai and Kasba.
The characteristics of the important litchi varieties are as follows:
i. Dehradun:
This variety is mainly grown in Uttarakhand, Punjab and Haryana. It is an early, regular and heavy bearing cultivar, with fruits ripening in the second week of June. Its fruits have an attractive colour. The fruit is susceptible to sunburn and cracking. The pulp is sweet, moderately juicy, medium soft in texture, TSS 17 per cent and acidity 0.48 per cent. The pulp/seed ratio is 3.75:1.
ii. Calcuttia:
This variety has proved very successful for growing in comparatively hot and dry areas. It is a heavy bearing cultivar with excellent fruit quality and yields 80-100 kg fruit per tree. Its fruits are large, attractive and mature in the third week of June. The fruit is less susceptible to sunburn and cracking. The pulp is sweet, soft in texture, moderately juicy with good flavour, TSS 18 per cent and acidity 0.49 per cent. The pulp/stone ratio is 4.78: 1.
iii. Seedless Late:
This is a descriptive name signifying a rather shrivelled seed and a much greater proportion of flesh in the fruit. Its fruit mature in the third week of June and are more prone to splitting than Calcutta. It is prone to irregular bearing. Fruits are deep, carmine red, pulp is soft, sweet and very juicy with an agreeable flavour. The juice has 18.7 per cent TSS and 0.53 per cent acidity. The pulp/stone ratio is 28:1. This variety comes into bearing rather late.
iv. Rose Scented:
The fruits of this variety have distinct rose aroma and hence called rose scented. The fruits have attractive pink skin. This is a medium yielding variety producing 80- 90 kg fruits per tree. Fruits are mostly heart shaped, pulp greyish white, soft and very sweet. The juice has 12.79 percent TSS and 0.33 per cent acidity. The pulp/stone ratio is 6.40:1. Fruits are moderately susceptible to sunburn and cracking.
v. Saharanpur:
This is an early variety ripening in the first week of June and yield heavily. The fruits are large, heart-shaped and deep orange to pink in colour. This variety resembles with Early Large Red and Pinjore Common and is considered to be a synonym of these varieties.
vi. Muzzafarpur:
This is one of the important litchi varieties mainly grown in Bihar. This variety bears profusely and yields around 80-100 kg fruit per tree. The fruits are deep orange to pink in colour and are less prone to splitting. The fruits of this variety generally mature in the first week of May in Eastern India and in the middle of June in Northern India. The juice has 18 per cent TSS and 0.48 per cent acidity. The pulp/stone ratio is 4.78: 1.
Some litchi cultivars were developed through selection and hybridization in India. Swarna Roopa is a selection made at Central Horticultural Experiment Station, Ranchi. It has attractive deep pink colour, small seed and high TSS/acid ratio. Its fruits are resistant to cracking.
Saharanpur Selection is a chance seedling selection. Its fruits ripen late in the third week of June. It has a very low percentage of fruit cracking. Two hybrids namely Madhu and H-73 have been released. Madhu (Purbi x Bedana) has higher number of fruits about 24 per panicles. H-73 is also a product of cross between Purbi x Bedana and has better fruit quality than Purbi.