Everything you need to know about growing lemons and limes. Learn about:- 1. Introduction to Lemon and Lime 2. Origin and Distribution of Lemons and Limes 3. Uses 4. Climate and Soil 5. Varieties 6. Propagation 7. Cultivation 8. Training and Pruning 9. Manuring and Fertilization 10. Harvesting and Postharvest Management 11. Yielding 12. Storage and Shelf-Life.
Contents:
- Introduction to Lemon and Lime
- Origin and Distribution of Lemons and Limes
- Uses of Lemon and Lime
- Climate and Soil Required for Growing Lemon and Lime
- Varieties of Lemon and Lime
- Propagation of Lemon and Lime
- Cultivation of Lemon and Lime
- Training and Pruning of Lemon and Lime
- Manuring and Fertilization of Lemon and Lime
- Harvesting and Postharvest Management of Lemon and Lime
- Yielding of Lemon and Lime
- Storage and Shelf-Life of Lemon and Lime
1. Introduction to Lemon and Lime:
The lemon (C. limon) is an evergreen tree native to Indochina and cultivated there for thousands of years. Citrus is, in last consequence, derived from Greek kedromelon “apple of cedar” (Greek melon is cognate to Latin malum “apple”); this name, however, did not signify lemon, but citron whose cultivation in Egypt is reported by Greek travelers.
The Romans, then, shortened the Greek name to citrus. The lemon was later imported to the basin of the Mediterranean Sea, where it has been cultivated for at least 2,000 years.
Lemons were brought to Europe by the Crusades; medieval or even older sources referring to lemons always mean the very aromatic, but juice-free citron, which was, at different times, recognized as the biblical apple (sour, indeed; actually, the fruit meant in the Bible was most probably pomegranate, which is most common in the Middle East) or the Apples of the Hesperides. Today, citron has still retained some cultic importance in the Jewish religion, where it is seen as a symbol of fertility.
In antiquity, citron was more grown as an ornamental and medicine than for food usage; Romans preferred vinegar and occasionally sumac berries to set sour accents in their cuisine. To my knowledge, not even citron peel has been used Culinary in Rome, but the Apicius suggests wine flavoured with citrus leaves as a surrogate for rose wine.
Origin of all Citrus species is unclear because of their ancient cultivation; C. limon is thought native in Central Asia; there is rumor that some wild populations of citron can still be found in Iran. Today, lemons are cultivated in many tropic or subtropical countries.
The USA and Mexico are the main producers; Mexico, due to its tropic climate, mostly accounts for limes. In Europe, most lemons actually stem from Spain or Italy. Citron is of comparatively little economic value. It is mostly grown in Sicily, Greece and Corsica.
2. Origin and Distribution of Lemons and Limes:
Lemons were originally developed as a cross between the lime and the citron and are thought to have originated in China or India, having been cultivated in these regions for about 2,500 years. Their first introduction to Europe was by Arabs who brought them to Spain in the 11th century around the same time that they were introduced into Northern Africa.
The Crusaders, who found the fruit growing in Palestine, are credited with bringing the lemon to other countries across Europe. Like many other fruits and vegetables, lemons were brought to the Americas by Christopher Columbus in his second voyage to the New World in 1493, and have been grown in Florida since the 16th century.
Lemons, like other vitamin-C rich fruits, were highly prized by the miners and developers during the California Gold Rush in the mid-19th century, since they were used to protect against the development of scurvy.
They were in such demand that people were willing to pay up to $ 1 per lemon, a price that would still be considered costly today and was extremely expensive back in 1849. The major producers of lemons today are the United States, Italy, Spain, Greece, Israel and Turkey.
Limes are grown on trees that flourish in tropical and subtropical climates. They were thought to originate in Southeast Asia. Arab traders brought lime trees back from their journey to Asia and introduced them into Egypt and Northern Africa around the 10th century. The Arabian Moors brought them to Spain in the 13th century and then, like many fruits, they were spread throughout southern Europe during the Crusades.
Limes made their way to the New World with Columbus on his second voyage in 1493, and were subsequently planted in many Caribbean countries whose hot, humid climates supported the cultivation of this fruit. Centuries later, British explorers and traders, who were readily using the vitamin C-rich limes that grew in their West Indies colonies to prevent scurvy, earned the nickname “limey,” a word that is often still used colloquially for persons of British descent.
The introduction of limes to the United States began in the 16th century when Spanish Explorers brought the West Indies lime to the Florida Keys, beginning the advent of Key limes. In the following century, Spanish missionaries attempted to plant lime trees in California, but the climate did not support their growth.
In great demand by the miners and explorers during the California Gold Rush as a fruit that was known to prevent scurvy, limes began to be imported from Tahiti and Mexico at this time in the mid-19th century. Today, Brazil, Mexico and the United States are among the leading commercial producers of limes.
India ranks fifth among major lime and lemon-producing countries in the world. India is perhaps the largest producer of acid lime in the world. It is cultivated in almost all the states, Andhra Pradesh. Maharashtra, Tamil Nadu, Karnataka, Gujarat, Bihar and Himachal Pradesh being major producing states, Lemons are less popular than limes in India. They are cultivated to a considerable extent commercially in Punjab, Rajasthan, and Tarai region of Uttar Pradesh.
Besides acid lime, sweet lime (C. limettioides), Tahiti lime (C. latifolia) and Rangpur lime (C. limonia) are also cultivated on a limited scale in India. Sweet lime, indigenous to India, is an important citrus fruit in north India. Tahiti lime grows well in Karnataka and Tamil Nadu. However, Sweet and Tahiti limes could not replace acid lime under commercial cultivation.
Rangpur lime is mostly cultivated for rootstock purpose:
An evergreen shrub growing to 3 m by 1 m at a medium rate. It is in leaf all year, in flower all year. The scented flowers are hermaphrodite (have both male and female organs) and are pollinated by Apomictic (reproduce by seeds formed without sexual fusion) and insects. The plant is self-fertile. We rate it 3 out of 5 for usefulness.
Lime plant may be a small, bushy tree, rarely taller than 12 feet with slender branches armed with short spines. Its dense foliage consists of small, pale green, blunt-pointed leaves with narrowly winged petioles (leaf stalks). Spineless selections are more compact and upright in growth, have darker green foliage, and are characterized by low yields. The flowers are small and white, in axillary clusters (around the stalk). Flowering occurs throughout the year but mainly in the spring.
The fruit are very small (1 ½ to 2 in.), round to oval. Fruits have very thin, smooth and leathery rind, greenish yellow at maturity. Flesh greenish yellow, juicy, highly acid with distinctive aroma. Moderate number of seeds, which are highly poly-embryonic (two or more plants from one seed).
3. Uses of Lemon and Lime
:
The commercial lime industry is based on the Key lime. Most of the crop is used fresh in limeade, mixed drinks, pies, and iced tea, and is squeezed onto seafood or other foods to bring out the flavor. It is also used in bottled lime juice and carbonated beverages. The principle by-product is lime oil, used in cosmetics and flavoring. Lemon has a characteristic, refreshing and sour odour. The fruit juice mainly contains sugars and fruit acids, mainly citric acid.
Lemon, on the other side, is mostly valued for its juice. Lemon juice displays a unique, intensive acidity which is at the same time tart and fruity. There is hardly one single cuisine in the world that does not make use of lemon juice (or the similar, but more aromatic lime juice). Lemon juice is especially popular in the East Mediterranean, e.g., in Lebanese tabbouleh, and also in Italy.
Lemon peel consists of two layers – The outermost layer (pericarp, “zest”) contains an essential oil (6%), that is mostly composed of limonene (90%) and citral (5%) plus traces of citronellal, α-terpineol, linalyl and geranyl acetate. The inner layer (mesocarp), on the other hand, contains no essential oil but a variety of bitter flavone glycosides and coumarin derivatives.
In grams per 100 g weight of food contains Water (90), Calories (28), Protein (0.8), Fat (0.5), Carbohydrate (8.2), Fibre (0.6) and Ash (5.4). In milligrams per 100 g weight of food contains Calcium (33), Phosphorus (15), Iron (0.5), Sodium (3), Potassium (137), Vitamin A (12), Thiamine (0.5), Riboflavin (0.02), Niacin (0.1) and Vitamin C (52).
Lemons are an excellent preventative medicine and have a wide range of uses in the domestic medicine chest. The fruit is rich in vitamin C which helps the body to fight off infections and also to prevent or treat scurvy. It was at one time a legal requirement that sailors should be given an ounce of lemon each day in order to prevent scurvy.
Applied locally, the juice is a good astringent and is used as a gargle for sore throats etc. Lemon juice is also a very effective bactericide. It is also a good antiperiodic and has been used as a substitute for quinine in treating malaria and other fevers. Although the fruit is very acid, once eaten it has an alkalizing effect upon the body. This makes it useful in the treatment of rheumatic conditions. The skin of the ripe fruit is carminative and stomachic.
The essential oil from the skin of the fruit is strongly rubefacient and when taken internally in small doses has stimulating and carminative properties. The stem bark is bitter, stomachic and tonic. An essential oil from the fruit rind is used in aromatherapy. Its keyword is refreshing.
Citrus species contain a wide range of active ingredients and research is still underway in finding uses for them. They are rich in vitamin C, bioflavonoids, acids and volatile oils. Of special interest in limes have been flavonoids called flavonol glycosides, including many kaempferol-related molecules.
While these flavonoids have been shown to stop cell division in many cancer cell lines, they are perhaps most interesting for their antibiotic effects. They also contain coumarins such as bergapten which sensitizes the skin to sunlight.
Bergapten is sometimes added to tanning preparations since it promotes pigmentation in the skin, though it can cause dermatitis or allergic responses in some people. Some of the plants more recent applications are as sources of anti-oxidants and chemical exfoliants in specialized cosmetics.
The bioflavonoids in the fruit help to strengthen the inner lining of blood vessels, especially veins and capillaries, and help counter varicose veins and easy bruising.
Several other fascinating research studies on the healing properties of lemons and limes have shown that cell cycles-including the decision a cell makes about whether to divide (called mitosis) or die (apoptosis-are altered by lime juice, as are the activities of special immune cells called monocytes.
Lemon oil is cold-pressed from the rinds of organically grown lemons. It takes 3,000 lemons to produce one kilogram of oil. The key constituents in lemon oil are limonene, gamma-terpinene, beta-pinene, alpha-pinene and sabinene.
The vaporized essence of lemon can kill meningococcus bacteria in 15 minutes, typhoid bacilli in just one hour, Staphylococcus aureus in two hours, and Pneumococcus bacteria within three hours. A mere 0.2 per cent solution of lemon oil can eliminate diphtheria bacteria in 20 minutes and completely inactivate tuberculosis bacteria. Lemon oil has antiseptic-like properties and contains compounds that have been studied for their effects on immune function.
Lemon oil may also be beneficial for anxiety, blood pressure, digestive problems, sore throats, and respiratory infections. It helps promote leukocyte formation, improves memory, strengthens nails, promotes a sense of well- being, and cleans the skin. Lemon oil was shown to have antidepressant effects.
A semi-drying oil obtained from the seed is used in soap making. An essential oil from the peel is used as a food flavouring and also in perfumery and medicines. A higher quality essential oil is obtained from the flowers. The peel contains 0.4% essential oil. An essential oil obtained from the leaves and young twigs is called ‘petit-grain oil’.
Yields are around 0.4%. The dried fruit rind has been used as an insect repellent in the clothes cupboard and also in potpourri. The juice of the fruit is used for polishing bronze and other metals that have been neglected. It can also be used for removing ink stains. Wood – nicely veined, it takes a beautiful polish.
4. Climate and Soil
Required for Growing Lemon and Lime:
Acid lime is tropical in its climatic requirements. Being tenderest among the citrus fruits, it is cultivated in all parts of the country, which are free from frost. The principal centres of cultivation are the drier regions. The areas, which are warm, moderately humid, free from strong winds and frost, are ideally suited for its cultivation.
Dormant plants can withstand temperatures down to about -6° c so long as this is preceded by a spell of 2 – 3 weeks of cool weather to allow the plant to acclimatize. If the change from mild to cold weather is more sudden then the plant will still be in growth and will be much more susceptible to damage and can be harmed by temperatures below 0° C.
The young growth in spring, even on mature plants, is frost-tender and so it is best to grow the plants in a position sheltered from the early morning sun. It is best if in a winter, minimum of 4°c is maintained. The lemon is widely grown for its edible fruit in warm temperate and tropical zones, there are many named varieties.
In north India, where the temperature occasionally falls below freezing, commercial cultivation of acid lime is risky. In frost-free areas of central and south India where rainfall does not exceed 750 mm/annum, it performs well. It grows successfully even up to 1,000 m above mean sea level, provided humidity is low and favorable.
In more humid regions of Assam and West Bengal, where rainfall is above 1,250 mm, lime becomes highly susceptible to citrus canker and powdery mildew making its trees unproductive and short lived. Sweet lime can be grown under a wide range of climatic conditions. Since it is harder than acid lime, Rangpur lime is raised throughout the country, particularly in drier regions (optimum temperature 20°-30°C). In humid areas, it becomes more susceptible to scab.
Lemons are more liberal in their climatic requirements than acid lime. Lemons are hardier than limes to both heat and cold. They have wide adaptability, since they thrive both in humid and semi-humid region, plains and areas receiving high rainfall.
Acid lime adapts well to a variety of soils and is not very exacting in its soil requirement. It grows fairly well in black and light loamy soil of uniform texture with a depth of 2-2.5 m, well drained and rich in organic matter and fertility is ideal for lime.
Lemons are also adaptable to a wide range of soils. Sandy loams or loamy soils possessing adequate drainage are generally preferred for successful cultivation. Lemons grow well and produce satisfactorily even in shallow soils provided the water and air regime are satisfactory at least up to 1 m depth.
Sweet lime can be grown on a variety of soils and is rather tolerant to defective soil conditions. However, it grows well-drained, deep loam soils. Lime prefers a moderately heavy loam with a generous amount of compost and sand added and a very sunny position. It prefers a pH between 5 and 6. It can tolerate a pH in the range 4.8 to 8.3.
Plants are intolerant of water logging. When growing plants in pots, compost comprising equal quantities of loam and leaf mould plus a little charcoal should produce good results.
5. Varieties of Lemon
and Lime:
True lemons fall into 2 distinct groups-acid and sweet lemons. Acid lemons are most extensively grown in India, while sweet lemons in South America and Egypt. On the basis of fruit and tree characters, true lemons are divided into 4 groups – Eureka, Lisbon, Anomalous and Sweet Lemon.
1. Eureka:
Fruit color lemon-yellow, surface slightly rogues, pitted; shape obviate to elliptical or oblong, medium-sized, base rounded, frequently necked, segments 9-10; pulp fine grained, pale, greenish-yellow, juice abundant, vary acid; quality and flavour excellent; seeds a few (0-6). It is a heavy-yielder and it begins bearing early. It has a tendency to bear fruits at the end of the branches and is partly covered with foliage. In Punjab, its fruits mature from August onwards.
2. Kagzi kalan:
Fruits medium, spherical, yellow, with apex slightly nippled, base rounded; rind thin, smooth, flesh acidic, light yellow, juicy; seedy (8-13 seeds).
3. Lisbon:
Fruit lemon yellow, surface smooth, shape ellipsoid to oblong. Size medium, base tapering into short neck, apex rounded into a prominent nipple, rind finely pitted, thin, segments-7-10; pulp fine grained, pale greenish- yellow; juice abundant, very acid, quality excellent; seeds a few (0-10).
4. Lucknow Seedless:
Fruit oblong; lemon yellow, smooth, apex nippled, base rounded; rind thin, axis hollow; segments 10-13, pulp light yellow and coarse, juicy, flavor good and sour; seeds absent to a few. The fruits ripen from November to January.
5. Villafranca:
It belongs to Eureka lemon group. Fruit oval-oblong, size medium to large, color bright lemon yellow, apex pointed, base rounded, rind smooth and thin; segments 10-12, flesh fine grained, light grayish-yellow; juice colorless, abundant, pulp melting, acid, flavour good; seedy (25-30 seeds).
Varieties of Nepali Oblong (Assam Lemon):
1. Fruits are Oblong to Obviate:
Lemon-yellow; apex nippled and base rounded, rind medium thick, axis hollow; segments 11-13, pulp light yellow and fine, juicy, flavour good, sour, seeds absent to a few. The fruits ripen during December-January.
2. Nepali Round:
The fruits are roundish and juicy with nipple seen just as a secar.
3. Pant Lemon I:
It is a selection of Kagzi Kalan. Fruits medium (80-100 g), round and smooth; rind thin; juicy; tolerant to canker, tristeza and dieback, It is the best replacement for kagzi kalan in the tarai region of Uttar Pradesh, because Kagzi Kalan is susceptible to tristezea, canker and dieback. It is self- incompatible.
Varieties of Lime:
The 4 original wild species from which the main hybrid species are derived:
1. Citrus medica (Citron):
Citron is thought to be native to India and then to have spread prehistorically, through cultivation, to the Near East and China. By 300 BC it was known in Greece, and by 20 BC it was being cultivated in Italy. Fruit are yellow, ovoid-oblong and can be large, measuring up to 30 cm long. They have a very thick rind and sour juicy parts.
The rind is used in making candied confectionery but Citron is used predominantly for medicinal and ritual purposes rather than for food. It is also used as a scent. From a ritual point of view, Citron is used in Buddhist ceremonies, and since about 100 BC, Citron has played an important part in the Jewish Feast of the Tabernacles.
2. Citrus grandis (Pummelo, pamplemousses, Shaddock):
Thought to have originated in South East Asia. Varieties differ in fruit sweetness, size, shape, colour, seediness and amount and kinds of essential oils. By 300 BC, Citrus grandis was being grown commercially in China. It is important in Chinese medicine and trees are grown also for their beauty and fragrance.
Before 1200 AD, cultivation of Pummelo had spread westward to India, North Africa and Spain. Citrus grandis is not grown commercially these days but is still grown as a garden tree.
3. Citrus reticulata (Mandarin, Satsuma and Tangerine) Naartjie (Afrikaans):
The Mandarin was probably domesticated in tropical Southeast Asia. By 500 BC it was known in China and by 300 BC it was being grown commercially in central China. By 400 AD, grafting methods were being used to clone favourable varieties. They were also using tree- nesting Taylor Ants (Oecophylla smaragdina) to defend trees.
It appears that the Mandarin has and still is the most important citrus species in China, both commercially and in people’s gardens. It was introduced to Japan at an early stage, where it also became the most favoured of the citrus species, and it was here that the Satsuma variety was developed. Despite its popularity in Asia, it was only in the 1800’s that Citrus reticulata was established in Europe, North Africa, West Indies, North and South America, and Australia.
4. Citrus aurantifolia (Lime):
Originates from tropical Southeast Asia, where it can still be found wild. Cultivars have been developed based on sweetness (usually sour), size, shape (round or oblong) and colour (yellow or green). All varieties have relatively thin skins. Lime fruit are used for preserves, garnishes and juices. Citral oil is extracted for use in perfumes.
1. Citrus aurantium (Seville, bergamot or sour orange):
Hybrid between Pummelo Citrus grandis x Mandarin Citrus reticulate – Bergamot is sometimes placed in a separate species Citrus bergamia, but is otherwise considered to be a variety of Citrus aurantium. Citrus aurantium originated in China and seems to have entered the written record there by 300 BC. It is recorded from Japan by about 100 AD. By about 100 BC, Sour Orange seeds appear to have reached Rome.
In China and Japan, Sour Orange is not usually eaten raw but used for:
(1) Making marmalade and candied peel;
(2) Producing essential oils for use in soaps and perfume; and
(3) Scenting tea using the flower buds. Bergamot yields neroli oil from the flowers which is used in perfumery (e.g. in Eau de Cologne), and Bergamot oil which is the substance added to Earl Grey tea to give it that distinctive flavour.
Origin and Distribution:
The bergamot is a variety of sour orange (sour orange-native to Asia), but the exact origin is unknown. It has been grown in Southern Italy and parts of France for centuries, and is now commercially grown in these regions.
It is Medium sized, yellow/orange skinned orange with a strong acid flavor, and aromatic rind.
Uses:
Oil is extracted from the rind which is used in the fragrance industry. The juice can be squeezed and used somewhat like lemon juice.
Plant Cultivation:
Small to medium sized tree, usually only 20-30 ft high. Trees are somewhat sensitive to freezes and grow best in areas having only limited frosts and freezes. Grows in conditions suitable for the average citrus, water frequently except during cold months. Fertilize 2-4 times per year. Can be container grown.
Propagation:
Commonly by seed which usually produce trees very near in fruit quality to their parent. Also be grafts.
2. Citrus australasica (Microcitrus austraiasica) – Australian Finger Lime:
Origin and Distribution:
Understory tree native to rainforests of Southern Queensland and Northern New South Wales, Australia.
It is elongated, bumpy skinned citrus up to 5″ long. Skin color and pulp are green, yellow, or red. Flavor is good, and very strong.
Uses:
Eaten raw. Often used to flavor drinks, jellies, and a variety of foods.
Cultivation:
Shrub or tree to 15 ft. Slow growing.
Propagation:
By seed, grafting, and budding. Can take 5-10+ years to fruit from seed.
It is likely a hybrid of a sour orange and citron (Japanese Citron). It is yellow to orange skinned citrus, usually medium sized, with highly fragrant rind and flesh. Flavor is acidic and tart. The fruit is relatively rare, and highly prized.
Origin and Distribution:
Native to China. Cultivated in Japan.
Uses:
The juice and rind and used in drinks and flavorings. Fragrance is extracted for use in perfumes, lotions, and soaps.
Cultivation:
Small tree, from 6-25 ft. in height. The yuzu is one of the hardiest of citrus fruits, reportedly surviving to 10 F. Fruits usually ripen towards the end of Fall, earlier than many other citrus.
Propagation:
By seed and grafts.
It is hybrid between Citron Citrus medica x Lime Citrus aurantifolia. The place and date of origin of the Lemon is uncertain but it probably came from China. Lemon is used for making lemonade, it is used in drinks, and for flavouring a wide variety of foods. The essential oil from Lemon is known as cedro oil, and is used as flavouring in the food industry and is also used in soaps, detergents and perfumes.
5. Citrus limonia (Canton lemon or Rangpur lime):
It is hybrid between Mandarin Citrus reticulata x Lime Citrus aurantifolia.
Thought to have originated in Southeast Asia and spread to China and India in cultivation so that by 1000 AD it was in southern China. This species is evidently grown widely as a garden tree in subtropical regions.
6. Citrus maxima (Pummel, Pomelo):
The largest citrus in the world, the pummelo can reach 12″ in diameter. Skin is usually yellow, with white or pinkish colored flesh. Flavor is excellent, sweetish-acidic.
Origin and Distribution:
Native to Southeast Asia and a number of Pacific Islands. It is grown commercially in Asia, and on a small, but growing scale in the United States.
Uses:
Commonly eaten fresh much like the grapefruit. The fruit is also squeezed for its juice.
Cultivation:
Small to medium sized tree, usually only 10-20 ft high, but may grow to 50 ft under ideal conditions. The pummelo is frost hardy, but grows best in warmer climates with lots of rainfall. It is an ideal choice for tropical zones, but also grows well in subtropical climates. Pummelos do quite well in Florida and California. Trees also grow well in swampy damp soil and are often found growing wild along river banks and streams. Trees can flower up to four times a year.
Propagation:
Commonly by seed which usually produce trees very near in fruit quality to their parent, but named varieties are propagated through grafts.
7. Citrus medica var. etroga (Etrog Citron):
It is medium to large sized bumpy yellow skinned citrus having a very acidic flavor. Primarily the skin is used, and the fruit plays a role in the Jewish Feast of the Tabernacles.
Origin and Distribution:
The origin of the citron is unknown, but it was the first cultivated citrus fruit, with records dating back to 4000 B.C. It was a common fruit in the Mediterranean region, and today is cultivated primarily in Sicily, Corsica, and Crete, Greece, Israel, as well as a number of Central and South American countries. Fruits have been known to cost $10-$50 a pound in the United States, sold for religious purposes.
Cultivation:
Small to medium sized tree, usually only 10-20 ft high. Trees are somewhat sensitive to freezes and grow best in areas having only limited frosts and freezes. They will stand below freezing temperatures for short periods of time, although the fruit is damaged. Citrons for use in religious ceremonies must not be grafted or budded onto other citrus rootstock.
Propagation:
Commonly by seed which usually produce trees very near in fruit quality to their parent, but named varieties are propagated through grafts.
8. Citrus mitis (Calamondin Panama orange, scarlet lime, Golden lime):
It is small citrus fruit resembling a miniature tangerine. Fruits are very juicy, with a sweet but acidic flavor. Common in tropical zones, but lesser known elsewhere.
Origin and Distribution:
Native to China. Has now spread throughout much of the South Pacific and the Americas.
Uses:
Eaten raw, although the flavor is very acidic. Often used to flavor drinks, jellies, and a variety of foods.
Cultivation:
Small tree, from 6-25 ft in height. Leaves are smaller than most citrus. The calamondin is hardy to temperatures in the mid 20’s. It can be successfully grown outside throughout California, Florida, and the gulf coast. It makes an excellent container plant in colder areas.
Propagation:
Often by seed, (unlike many other citrus). Seeds are polyembryonic and may produce up to 3-5 seedlings each. Commercial growers propagate the calamondin by cuttings which bear fruit in just two years.
9. Citrus paradisii (Grapefruit):
Hybrid between Pummelo Citrus grandis and Sweet Orange Citrus sinensis. This hybrid species is thought to have originated on the island of Barbados in about 1750. Further varieties of Grapefruit were developed mainly in Florida and Texas, USA.
10. Citrus sinensis (Edible, Sweet, Valencia, Navel Orange):
Hybrid between Pummelo Citrus grandis x Mandarin Citrus reticulate- Although originating from the same parent species as Citrus aurantium, the actual parents were different varieties to those of Citrus aurantium. There are clear records of Citrus sinensis in China only by the 1100’s and in India by the 1300’s.
By the 1400’s it had spread to the Mediterranean. From the mid 1600’s onwards, European colonists spread it around the world’s tropical regions. The Navel variety originated in Bahia, Brazil in the 1800’s.
Lime has been cultivated in many centuries. There are not improved varieties of acid lime (kagzi lime). It is also known as sour lime, Mexican lime, key lime, West Indian lime. Limes are multiplied sexually, because of polyembryony (many embryos). There is a great variation in Maharashtra, Andhra Pradesh and Tamil Nadu varieties.
1. Pramalini:
It bears fruits in clusters of 3-7 and yields 30% more than the normal kagzi lime. The fruits have 57% juice, which is higher than Vikram (53%) and normal lime (52%). The variety is grown in Maharashtra. It was identified by clonal selection and released for commercial cultivation. It is resistant to canker-free and prolific-bearer.
2. Vikram:
This also bears fruits in clusters of 5-10 and some off-season fruits during September, May and June. It gives 30-32% more yield over the normal lime. The variety is grown in Maharashtra. It was identified by clonal selection and released for commercial cultivation. It is resistant to canker-free and prolific-bearer.
3. Chakradhar:
It is a seedless strain of acid lime. The plants are erect, compact and dense in habit. Fruits are round, with papery rind, containing 60- 66% juice and almost seedless compared with 52-62% juice and 6-8 seeds/fruit in others. Bearing starts by fourth year of planting. It bears fruits during January-February, June-July and September-October.
4. PKM 1:
Its fruits are round, medium to large-sized, with an attractive yellow skin, and 52.31% juice. It is high-yielder then the local strains.
5. Seedless Lime:
It is a new selection of lime. Fruits are oblong, skin thin, primrose colored, prolific-bearer, yields double that of normal lime but late.
6. Tahiti (Persian) Lime:
The large-fruited limes of Tahiti group are different in many characters from the true limes. The trees are larger, spreading and more resistant to cold, nearly thorn less, leaves much larger, and of different shapes; fruits much larger and almost seedless. It is a triploid. There are no varieties being grown in India.
The fruits are globose, lemon yellow, rind light, smooth; flesh yellowish-white, juicy and sweet, seeds have light colored inner seed coat and chalazal spot. The sweet lime is grown for rootstock purpose and commonly for its non-acid fruits. Its two varieties are under cultivation in India.
1. Mithachirkna:
Fruits spherical, globose, yellow colored, smooth, glossy surface with oil glands; rind thin, leathery; flesh medium coarse. Juicy, sweet; seeds few.
2. Mithotra:
Fruits large with depressed apex and necked back; lemon yellow colored; rind tough, thick with oil glands; flesh yellowish-white, juicy coarse, sweet and well flavored, more pleasantly flavored than Mithachikna.
It is indigenous to India. Trees evergreen, spreading in growth habit and highly productive. Rind and pulp orange-coloured, rind thin and readily separates from the pulp ball. It is commonly grown for rootstock purpose. To a limited extent it is also grown as an ornamental plant and for its fruits, whose juice is used for making lemonade. There are several strains of Rangpur lime, but no recognized varieties.
6.
Propagation of Lemon and Lime:
1. Propagation through Seeds:
Acid lime is propagated commercially through seeds, It can be propagated by cuttings, layering and budding owing to high intensity of polyembryony (90- 100%) and least chance of contamination of viral diseases. Besides, seed propagation is the cheapest and easiest method.
The seed is best sown in a greenhouse as soon as it ripe after thoroughly rinsing it. Sow stored seed in March in a greenhouse. Germination usually takes place within 2-3 weeks at 13 °C. Seedlings are liable to damp off so they must be watered with care and kept well ventilated.
The seed is usually polyembryonic, two or more seedlings arise from each seed and they are genetically identical to the parent but they do not usually carry any virus that might be present in the parent plant.
When large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for at least three growing seasons before trying them outdoors. Plant them out in the summer and give them some protection from the cold for their first few winters outdoors.
The overall performance of seedlings is better than bud lings. Seedlings have less mortality, precious and sturdy. They can withstand vagaries of nature better, tolerate diseases better are prolific and long-lived.
For seed elite mother tree which is free from diseases, producing large-sized quality fruits is selected in the month of June-July. Fully matured and ripe fruits are harvested from these elite trees. The seeds should be bold, well- developed, true-to shape and size of the variety.
Freshly extracted seeds are used for propagation. Maximum germination can be obtained by sowing freshly extracted seeds up to 2 days only. As the sowing of seeds is delayed, less germination takes place.
The seeds are first treated with a suitable fungicide to prevent damping off. They are sown with 15 cm x 2.5 cm spacing on the raised beds of sandy loam with well-rotten farmyard manure or compost during-June-July or November- December. The seedbeds are drenched with 1% Bordeaux mixture to control damping off. The seedbeds are watered regularly.
Seedlings are transplanted to a raised nursery bed (for hardening) prepared in well-drained, fairly deep and fertile soil. Seedlings are transplanted at 45-60 cm from row-to-row and 20-30 cm within the row. Nursery beds are frequently watered and fertilized with nitrogenous fertilizers and weeded for quick growth.
Acid lime seedlings are retained for-12 months in nursery beds and then lifted and disposed off in polybags or earthen pots, after immunization with mild strain of tristeza.
The seedlings of kagzi lime take about 12-14 months to become ready for transplanting in the main field. Spraying of urea (1-1.5%) at monthly intervals encourages their growth. Treating seeds with 40 ppm GA also helps enhance their growth.
2. Propagation through Layering:
Sweet lime is propagated by layering or hard woodcuttings. It takes lesser time to establish the plants than budlings. Sub terminal leafy cuttings with 3-4 leaves at the give 100% success in rooting if dipped in 50 and 100 ppm IBA for 24 hr or in 2, 000 ppm for 10 seconds. The plants raised from cuttings are shallow-rooted and are surface feeders. Tahiti lime is multiplied by ground and air layering, whereas Rangpur lime is propagate by seeds only.
Lemons are also propagated by budding, layering, marcutting, stems cuttings and seeds, budding is preferred, as budded plants are precocious, produce more uniform and root and trunk diseases can be avoided by using suitable rootstock.
Acid lime – Gajanimma (C. pennivesiculata) is most promising rootstock followed by rough lemon for acid lime. Rough lemon can be utilized as a rootstock for acid lime in Andhra Pradesh, Tamil Nadu and Maharashtra. Rootstocks for acid lime are sometimes used in arid zones against drought, saline, alkaline and calcareous soils. Otherwise under normal conditions, seedlings are more preferable in acid lime.
7. Cultivation of Lemon and Lime:
Field Preparation:
If the field is already been under cultivation and well maintained, nothing further may be required for preparation. If the field is a new and uncultivated then well dressing for planting is required. The existing vegetation should be cleared completely. Then thorough and deep ploughing twice or thrice is done and finally leveled a season in advance after harrowing and cultivating to a fine tilth.
Limes are planted at a distance-of 4-6 cm.
They should be planted as per spacing given below:
A close spacing of 3 m x 3 m can be adopted initially and after about 8-10 years, alternate rows can be removed for providing sufficient space for each tree as it advances in age and grows. Sweet lime and Tahiti lime are set at 6.0-7 m on fertile soils and at 5.0-5 5 m on low fertile soils. Rangpur lime is generally grown on bunds or on bunds or on either side of a drive or road or any at varying spacings.
Lemons require wider spacing than limes (6.0-8.0 m). It depends on variety, soil and rainfall. Square system of planting is usually followed for limes and lemons.
Pits of 90-100 cm3 size are prepared with recommend spacing in summer or at least 2-3 weeks before planting. The pits are exposed to weather for about 15- 20 days depending upon the locality, soil and climate.
Then the pits are burnt with trash for sterilization and refilled with the first half of the dug-up soil mixed with tank silt, red earth, farmyard manure, bone meal or super phosphate and pesticide against root grubs and termites, a fortnight before planting and watered for settlement of the soil.
Planting is done at the onset of the rainy season (June-August) or in light rains. In areas affected with heavy rainfall (Assam) the planting should be done at the end of the rainy season. This will avoid stagnation of water in pits, in areas of assured irrigation during summer, planting can also be done up to February.
Summer planting is not advised, because it requires frequent watering and protection from the hot and desiccating winds and high temperatures.
After Planting Care of Young Plants:
The newly planted young plants need protection during the initial 3-4 years from excessive heat, moisture and cold. Young trees may be trained to a single stem, with no branches up to 60-70 cm from the ground level. The bare trunks must be protected by white washing the trunks or covering the trunk with strain paper of gunny cloth.
In northern plains of India, the plants should be protected from frost and low temperatures. Therefore, frequent light irrigations or windbreaks should be provided. Young plants flush 4 or 5 times in a year. During flushing, there is an incidence of leaf miner, citrus butterfly and canker, which should be controlled promptly.
Before flushing, light manuring with nitrogenous fertilizer is required. Frequent watering of the newly set plants is also necessary. During the rain avoid water stagnation to protect the roots. Proper drainage should be available in field for this purpose.
8. Training and Pruning
of Lemon and Lime:
The young lemon trees produce long, rambling branches, and bear fruits at the tip of the laterals. This results in the drooping of the branches, except a few, which are necessary for the framework of the tree. The rest, particularly those in the centre, should be removed. Mature lemon trees require more pruning. Annual light pruning of shoots maintain production of high-quality fruits.
Young acid lime plants are trained by modified central leader system, with a smooth trunk up to 75-100 cm height from the ground level and 4-5 well- spaced and well-spread branches, as scaffolding branches. All sprouts appearing on the trunk up to a height of 75-100 cm should be removed. Once a young plant is trained to a desired shape, it requires very little pruning. Light pruning may be given during later years.
Lightly pruned young trees make greater development of roots and shoots, producing fruits earlier than those pruned heavily. Remove dead, diseased and broken, criss-cross branches. Removal of water suckers is also essential. Pruning may be done just after harvesting. Pruned cut ends may be smeared with Bordeaux paste or Blitox.
9. Manuring and Fertilization
of Lemon and Lime:
Use of fertilizer and manure depends on species and area. Organic manuring is more beneficial, especially for citrus than inorganic manures. It is always advantageous to give a liberal dressing of bulky organic manure, as it keeps the soil mellow and in a good physical condition besides supplying plant nutrients.
The N should be supplied in the form of farmyard manure (25%), oil cakes (25% and chemical fertilizer (50%), while P and K as super phosphate and sulphate of potash or muriate of potash respectively. In Andhra Pradesh, manuring is done twice a year-December-January (prior to main flowering) and June-July (during fruit development)-with equal quantities of manures and fertilize.
A fully-grown plant of acid lime should be given 50 kg farmyard manure. 900 g N, 250 g P2O and 500 g K2O/year. Total quantity of farmyard manure and P2O5 and half of N and K should be applied after rains, whereas the remaining half of N and K after flowering during March-April.
Lime application is also recommended for acid lime in Gujarat. Nitrogen (500 g/tree) increases the height and yield, while heavy doses of P and K are detrimental. Manures and fertilizers are generally applied through soil in tree basins by trench method.
Limes and lemons require more water than oranges. Under tropical conditions acid lime needs 875 mm water/year. At critical stages of growth and development sufficient moisture should be maintained. Water scarcity of water at critical growth and development phases will check the size and quality of fruits and yield and will increase fruit drop.
Therefore, it is necessary to provide adequate irrigation, especially during the fruiting and dry periods of the year.
Irrigation may be done using basin system or by drip irrigation. Drip irrigation gives highest fruit yield, with better fruit quality, besides saving water up to 22-50%.
In winter season, limes and lemons should be irrigated at 10-15 days, whereas in summer at 5-7 days interval. Highest yields can be obtained in acid lime at 50-60% of available soil moisture depletion. It is advisable to maintain soil moisture at 55-56% field capacity from bloom until the young fruits exceed 2-5 cm diameters, thereafter temporary wilting in leaves can be used as guide for irrigation.
Aftercare includes orchard management including soil condition, tillage, mulching and weed control. Soil should be weed free. For soil moisture and fertility conservation add green manure and provide aeration to the root system. The alleys may be ploughed at least twice a year, one just after the onset of the monsoon rains and next after the cessation of rains. Light hand digging or hoeing of the basin after every 3 or 4 irrigations is essential to avoid soil becoming hard.
In tropical areas, mulching plays a significant role for citrus. Mulching is essential for at least 6 months in a year. Mulching of tree basins is very necessary to check weed growth, conserve soil moisture, hinder soil temperature fluctuations and activate the biological properties of soil.
After weeding, basin in mulched with dry leaves, paddy husk, groundnut husk, sawdust, wood shavings, stubbles of cereal crops, coconut coir and dry grass. Mulching of basin to a thickness of 8 cm 100-120 Kg/ basin of 16 m2 is recommended for acid lime particularly from January to June. Green leaf mulch at 30 kg/tree is also effective.
In citrus orchards, weeds are controlled by using Monouron, Diuran and Gramoxone. Diuron @ 2-5 kg in 500 liters of water may be sprayed on soil, 30-40 cm away from the trunk as pre-emergence spray. It checks weeds for about 10 weeks.
Diuron as pre-emergence application and Gramoxone + Diuron as post-emergence application are effective in reducing divot weeds. Diuron (3 kg) + Gramoxons (1.5 kg) once in 3 months in effective to control weeds in acid lime gardens. Post-emergence application of Glyphosate (2.0 kg/ha) at fortnightly intervals is most effective.
Citrus plants when attain the age of 5 or 6 years the vacant interspaces may be used to cultivate legumes (berseem, lucerne, cowpea, groundnut, green gram and cluster bean) or vegetables like pumpkin, tinda, onion, mung, cluster-bean in summer and peas, turnip, carrot and cole crops in winter. Marigold flowers also be raised as intercrop.
10. Harvesting and Postharvest Management of Lemon and Lime:
Color break of fruits from green to yellow is ideal time for harvesting limes and lemons. However, they should be harvested when mature but still green so that their acidity at the peak may be utilized. In some areas, limes are picked when they turn from green to yellow. Lemons are frequently picked with size, without regard to maturity.
The fruits should neither be plucked nor torn off but cut off with clippers. Generally limes and lemons are harvested with a pole harvester, having an iron hook and a net at one end.
Quality Characteristics:
Color, size; shape; firmness; smoothness; freedom from decay; and freedom from defects including bruises, oil spotting, dryness, freezing injury, and stylar- end breakdown are the main quality parameters. High quality limes should be oval, firm, with smooth peel and deep green (Persian) or green and/or yellow (Key lime) color.
Limes should be turgid, and free from decay, splitting and blemishes. Juice content by volume of 30% or higher and color (mature-green limes have a much longer post-harvest-life than those picked when yellow; the latter must be marketed soon after harvest).
Color break of fruits from green to yellow is ideal time for harvesting limes and lemons. However, they should be harvested when mature but still green so that their acidity at the peak may be utilized. In some areas, limes are picked when they turn from green to yellow. Lemons are frequently picked with size, without regard to maturity.
i. Optimum Temperature:
10-13°C (50-55 °F) depending on cultivar, maturity-ripeness stage at harvest, and duration of storage + transport (up to 6- 8 weeks).
ii. Optimum Relative Humidity:
90-95%. 
To calculate heat productions multiply ml CO2 /kg. hr by 440 to get Btu/ton/day or by 122 to get kcal/metric ton/day.
Rates of Ethylene Production – <0.1 μl/kg. hr at 20° C (68° F)
iii. Responses to Ethylene:
Ethylene causes limes to lose their green color and unmask their yellow pigments, which is undesirable for marketing green limes. Removal of ethylene from lime storage facilities can be beneficial in retarding loss of green color and delaying decay incidence.
Responses to Controlled Atmospheres (CA):
A combination of 5-10% O2 and 0-10% CO2 retards senescence (loss of green color) of limes, but is inadequate for decay control. Exposure to > 10% CO2 and/ or < 5% O2 can result in scald-like injury, decreased juice content, off- flavors, and increased susceptibility to decay. Commercial use of CA on limes is very limited.
Maturity Standards, Grade Standards and Packing:
Persian limes must attain a size of 4.76 cm (1.87 in) in diameter and a juice content of 42% by volume. There are no size requirements for Key lime, but juice content must be 42% by volume. Persian limes are packed in 10 lb (4.5 kg), 20 lb (9.1 kg), and 40 lb (18.2 kg) cartons for storage and shipping.
Ethylene Production and Respiration:
Under optimal storage conditions, respiration rates of limes are < 10 mg CO2 kg-1 h-1. The rate of ethylene production is < 0.1 μL kg-1 h-1 at 20 °C.
11. Yielding of Lemon and Lime:
A good acid lime plant (7-year-old) 2,000-5,000 fruits annually, the average yield being 3,000-3,500 fruits/tree. A lemon tree on an average yields 600-800 fruits/tree. The yield may increase up to 1,000-1,200 fruits/tree under favorable conditions.
De-greening of citrus fruits in India is achieved with the aid of calcium carbide crystals in the ripening chambers. Calcium carbide releases ethylene gas, which destroys green color and allows the development of yellow color affecting the quality of fruits. A simple technique has been developed to de-green the Tahiti limes.
In this technique, fully matured limes are kept along with ripening bananas in airtight chambers in a 6:1 ratio of lime: banana. The ethylene gas released during ripening of banana, allows de-greening of limes within 24 hr.
Waxing is a method by which wilting and shriveling of fruits can be avoided and their shelf-life can be extended. Dipping fruits in 12% waxol extends their storage life both under common storage and cold storage. The wax emulsion reduces respiration and transpiration by sealing of the pores of the rind of fruits. Sealing fruits in polythene bag with ventilation is also helpful is extending the storage life of fruits.
12. Storage and Shelf-Life of Lemon and Lime:
Acid limes can be stored in cold storage for 6-8 weeks at 8.3°- 10.0°C and 85- 90% relative humidity, while lemons can be stored for 8-12 weeks at 7.2°-8.6°C and 85-90% relative humidity. Harvested fruits should be brought to packing sheds as soon as possible. They should never be allowed to stay under the sun for a long time.
At present, no grading system is followed in India, in spite of the legislative acts enacted. The citrus fruits in India are however, roughly graded by the vendors on the basis of size only. Limes should be cooled and stored at 10 °C with 95% RH. Under optimal conditions, limes can be stored up to 8 weeks. CA storage can retard senescence, but commercial use is very limited.
Shelf-Life:
Use of growth regulators-2, 4-D and 2, 4, 5-T-is also employed for extending the shelf-life of fruits. The shelf-life can be extended up to 25 days by dipping them in 2, 4-D (50 or 100 ppm) aqueous solution. Followed by waxing before packing. The GA3 (200 and 500 ppm) and Cytokinin (10 and 25 ppm) enhance their shelf-life, reducing decay and weight loss without affection quality.