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Chromosome Number: 18
Taxonomic Classification
Class
:
Magnoliopsida
Order
:
Capparales
Family
:
Brassicaceae
Genus
:
Raphanus
 
Radish is cultivated throughout India. West Bengal, Bihar, Uttar Pradesh, Punjab, Assam, Haryana, Gujarat and Himachal Pradesh are major radish-producing states.
   
Climate and soil  

It grows well under mild to cool climate. However, Asiatic varieties can tolerate higher temperature. The temperature of 10°–15°C is optimum for proper development of roots, texture and flavour. Maximum root growth occurs initially at 20°–30°C but later at temperature of 10°–14°C. This is more applicable to European varieties than the Asiatic ones. More foliage growth is favoured at higher temperature above 25°C. The long acclimatized varieties grown in India can withstand heat and rain much better than the European types. In hot weather, roots become more tough and pungent before reaching the edible maturity. The optimum uptake of nutrients and rise in dry-matter content occurs at 20–25°C. Long photo-period and warm temperature favour early bolting even prior to proper development of roots. Normally plants bolt when days are 8–10hr long. At lower temperature, pungency is reduced and crop can easily withstand frost.

Radish can be grown almost in all kinds of soils but friable loam soil with high humus content is most suited. It can be grown in fairly acidic soils having a pH of 5.5–6.8. Sandy loam soils are best-suited for early harvesting. In heavy soils, deformed roots with fibrous laterals are produced. The roots become fibrous and forked when grown in soils having unrotten humus with hard and stony subsoil.
 
Varieties

Radish varieties are broadly classified into 2 types—Asiatic or tropical and European or temperate. The improved varieties grown in different parts are described below:

Asiatic or tropical

Arka Nishant

Its roots are medium-sized, 25cm long, 3–4cm in diameter, marble-white with crisp texture and mild pungency, resistant to pithiness, premature bolting, root branching and forking.

IHR 1-1

The roots are 30cm long, thin, free from premature bolting, pithiness, splitting and forking and flesh is mildly pungent. Average weight of root is 300g. The root surface is smooth and shining white. It is highly resistant to white rust. It becomes ready for harvesting 45 days after sowing.

Japanese White

Its roots are cylindrical, stumpy, 22–25cm long and 5cm in diameter, skin snow white, flesh crisp, solid and mildly flavoured. It matures in 45–50 days. It is suitable for sowing from October to December in plains and July to December in hills.

Jaunpuri Giant or Newari

Cultivated around Jaunpur in Uttar Pradesh, it grows up to 75–90cm in length and 50–60cm in girth weighing 5–15kg or more.

Kalyani White

The roots are 25–30cm long, uniform in size with a blunt end. The skin is pure white, and flesh mildly pungent. Plants are having light green top. It can be grown throughout the year except during summer. The edible maturity approaches in 45–50 days.

Nadauni

A popular variety in Himachal Pradesh, its roots are long, tapering, light pink in colour, top dark green with cut leaves.

Punjab Safed

Its roots are 30–40cm long, 3–5cm thick, white, tapering, smooth, mild pungency and free of forking. It is quick-growing with roots remaining edible for 10 days after attaining full size.

Pusa Chetki

A selection from exotic material, its roots are medium-large (25–30cm), stumpy, pure white, tender, smooth and mildly pungent. It matures in 40–45 days. Since it can tolerate high temperature, it is suitable for sowing from mid-March to August.

Pusa Desi

Its roots are pure white, 30–35cm long, tapering with green stem end, pungent and heavy yielder. It matures in 50–60 days. It is suitable for sowing during mid-August to October in northern plains.

Pusa Himani

The roots are 30–35cm long, medium thick, tapering white with green shoulders, flesh pure white, crisp, sweet flavoured with mild pungency. The top is short, leaves green having less hair than Japanese White. It takes 60–65 days from sowing to maturity. It has wide adaptability and is grown almost throughout India.

Pusa Reshmi

Its roots are 30–35cm long, white with green tinge on top portion. It is suitable for early sowing in cooler months but tolerant to slightly higher temperature. Good-sized roots become ready for harvesting in 55–60 days.

European or temperate varieties

Chinese Pink

The roots are 30–45cm long, cylindrical with blunt end. The skin is shining red and smooth, flesh is white, crisp solid and mild pungent. It matures in 45 days. It is most-suited for hills but grows well in plains with mild climate.

Rapid Red White Tipped

Its roots are smooth, small, round, bright red with white tip, flesh pure white, crisp and snappy. Extra early, it matures in 25–30 days.

Scarlet Globe

Its roots are round, small, 2cm in diameter, bright red in colour. The flesh is crisp and white. It takes 25–30 days from sowing to complete root formation. The delayed harvesting results in pithiness. The foliage height is 10–15cm.

White Icicle

The icicle-shaped roots are straight and tapering with small tops. Skin is pure white, flesh is icy-white, crisp, juicy and sweet flavoured. It becomes ready for harvesting 30 days after sowing.

   
Cultivation  

Preparation of land

The land should be prepared by thoroughly ploughing the field 4–6 times and levelling well by planking. All the stubles of previous crop should be removed. The surface of soil should be kept loose for proper growth and development of roots.

Sowing

This is mainly a cool season crop. However, it can be grown almost throughout the year depending upon the climatic conditions. Sowing is done from September to January in plains and March to August in hills. In mild climate, it is grown round the year but the best quality roots are produced from November and December sowings. April–June and October–December are best sowing time for Maharashtra, while March–August for Karnataka, Tamil Nadu and Andhra Pradesh. For a regular supply of fresh roots, sowing should by done at 10–15 days intervals. Bold seeds germinate better, producing vigorous and healthy plants.

About 5.5–11kg of seed is enough for a hectare crop. Radish can be sown on ridges or on flat beds. The distance between ridges and within the rows varies according to the variety. The temperate varieties which become ready for harvesting in 25–30 days are given closer spacing compared with tropical or Asiatic types which take longer time to mature. Seeds are sown on 23–25cm high ridges spaced 45cm apart. However for European varieties, ridges are spaced 20–30cm apart. The spacing within the rows is kept 4–8cm after thinning. Normally seeds are sown 1.5–3cm deep while surface sowing is done for round cultivars and immediately covered with soil. The young plants look pale when sown deeper than 3cm and the root maturity is also delayed. Seeds germinate within 5–10 days of sowing in properly moist soils.

Manuring and fertilization

Since radish is a fast-growing, short period crop, it requires sufficient readily available plant nutrients. Different doses of manures and fertilizers have been recommended for various regions of the country. Application of 25–40 tonnes of farmyard manure, 50–80kg of N, 50kg of P and 50kg of K/ha should be done. Farmyard manure should be applied at the time of land preparation. The complete doses of P and K and half of N should be added to the soil before sowing. The remaining half of N is topdressed in 2 split doses during early plant growth and root formation. Foliar application of urea (2%) enhances vegetative growth at initial stage. In the acid soils it should be properly used in combination with organic manures.

The B deficiency can be controlled by soil application of 15–20kg/ha of borax before sowing. Molybdenum deficient plants develop narrow and leathery leaves and growth is checked. Application of 1.2kg/ha of sodium or ammonium molybdate controls this disorder.

Interculture

Generally 2–3 weedings are required. First weeding should be done prior to thinning. After thinning, hoeing is done to facilitate proper soil aeration for fast development of roots. One earthing-up is necessary at early stage of plant growth. However, second hoeing and earthing-up are done when the roots pick up growth. In radish there is a tendency to bulge out of soil with increase in size, earthing-up helps in proper development of roots. After every irrigation light hoeing is done to break soil crust wherever it is formed. Pre-emergence application of TOK E 25 (Nitrofen) @ 2kg/ha effectively controls weeds.

Irrigation

Radish requires sufficient water right from germination to harvesting. The number of irrigations depends upon type of soil as well as climatic conditions. A light irrigation is given prior to sowing to provide sufficient moisture to facilitate germination under dry conditions. First irrigation can also be given immediately after sowing of seeds if not given earlier. Later on irrigate the field at 3–4 leaves stage or when plants attain height of 5–7cm. The subsequent irrigations are given at 5–7 days interval in summer and 10–15 days during winter depending on prevalent weather conditions. Care should be taken that the field should not become dry and compact which can check root development. Maximum water consumption occurs 15–18 days after germination of seeds. Drip irrigation is used for efficient water use. Subsurface drip irrigation gives better results than the surface, especially in the sandy loam soils.

Growth regulators

Germination is stimulated when seeds are sown after soaking in NAA (10 and 20ppm) solution. The concentration of 20ppm increases edible root yield. Seed treated with GA3 (5ppm) gives high germination, enhancing its yield.

The high cropping intensity is adopted in vegetable-based cropping system to get maximum returns. The cropping sequence of radish–tomato–bittergourd and radish–onion–okra is practised in north-western part of India. Radish is grown as a single crop or intercropped with potato. However summer radish can be intercropped with Amaranth especially in the eastern part of India.

Seed production

Temperate winter varieties of radish are biennial, requiring low temperature (0°–4°C) for a period of 40–60 days to induce bolting and flowering. Seed production of these varieties is restricted to temperate hilly regions. Sowing of seed is done in September.

Temperate summer varieties are grown during summer in the hills. These are short-duration varieties. Seed production of these can be done both in summer and autumn seasons in the hills.

Tropical varieties can produce seed both in tropical and temperate regions of India. Their sowing is done in September or October.

Seed production of radish is done either by seed-to-seed or in-situ and root-to-seed methods. It is advisable to use root-to-seed method for quality seed production. The selected roots for stecklings are planted 60cm × 60cm or 60cm × 45cm apart. In the latter method, the stecklings are prepared by cutting lower 2-thirds portion of roots and trimming off the tops in the same preparation. The varieties should be isolated 1,000–1,600m apart to produce pure true-to-type seed. Application of 94kg of N, 55kg/ha each of P and K should be done to get good seed yield. The crop is harvested when 70% of the pods turn yellow. Thrashing is done after curing and drying the harvested crop. The seed is cleaned, dried and graded properly. Average seed yield of European varieties is 570–780kg/ha while Asiatic varieties yield more.

   
Harvesting & Postharvest management

It should be harvested when its roots are still tender. They are pulled out vertically with least breakage. The edible maturity period varies from 25 to 60 days depending upon the cultivar. Early-maturing European varieties mature in 25–30 days while Asiatic types take 45–60 days. Manual harvesting is common in India. The delayed harvesting results in pithiness and tastes bitter hence become unfit for market. The average yield of Indian cultivars is 150—200 q/ha, whereas the European cultivars produce 50–70 q/ha.

The harvested roots along with tops are properly washed, graded and tied in bundles. About 3–6 roots are tied in a bunch depending upon the size of roots. These bundles are loose packed in baskets and transported to the market. Harvested roots can be stored for 3–4 days at room temperature without impairing its quality. However, it can be stored up to 2 months in cold storage at 0°C with 90–95% relative humidity. These are stored especially to fetch better return.

   
Physiological Disorders
Brown heart is a commonly occurring disorder in radish and turnip due to B deficiency. At first, dark spots usually appear on the thickest part of the root. The plant growth is checked and it remains stunted. The leaves are smaller than the normal and lesser in number and later on show variegated appearance with yellow and purplish red blotches. The leaf stalks show longitudinal splitting. The root remains small, showing distorted and greyish appearance. This is controlled by soil application of 15–25kg/ha of borax. A foliar application of 0.1% B increases the yield besides controlling this physiological disorder.
Nutritional Value
 
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Chromosome Number: 22
Taxonomic Classification
Class
:
Magnoliopsida
Order
:
Sapindales
Family
:
Sapindaceae
Genus
:
Nephelium
 

Rambutan is another important fruit tree of humid tropics mostly confined to south-east Asia especially Indonesia, Malaysia and Thailand. In the recent past, this fruit has spread to other humid tropical regions of the world including India. Rambutan, a medium-sized evergreen tree with an open structure growing 12–15m high, is a native of the Malaysian-Indonesian region. It produces ellipsoidal fruits in clusters of 15–20 fruits. Fruits weigh 40–50g each and resemble litchi but because of long, thick, soft hairs or spines on the surface these are known as rambutan (in Malay ‘rambut' stands for hair). The hairy outgrowth has eye-catching red and yellow colours and it imparts a distinctive exotic appearance to its fruits.

The thin, leathery fruit skin is easily peeled away, revealing a pearly white, gelatinous, juicy pulp (aril) surrounding a large seed. The pulp tends to be attached to the seed in some varieties. In others, it can be readily separated. The translucent pulp is sweet or sub-acid with a refreshing flavour and is akin in many ways to litchi pulp. The fruits are a good source of sugars and vitamin C and are eaten as a fresh dessert fruit. The pulp can be preserved in syrup or used in several conserves.

   
Climate and soil  

Rambutan is strictly a tropical fruit requiring a moist warm climate with a well-distributed annual rainfall of at least 200cm. The plants can grow at 10–500m above mean sea-level, but areas with dry winds are harmful for the tree growth, which leads to browning of leaf margins. In Indonesia, this fruit is distributed in areas with the altitude 30m above sea-level, with 90–150 rainy days in a year and temperature 20°–30°C and relative humidity 60–82%.

Rambutan trees grow best in deep, well-drained soils, rich in organic matter. They can grow in heavy soils, if well-drained, and in sandy soils, if these have good organic matter. A pH of 4.5–6.5 is suitable. At higher pH, iron and zinc deficiencies are common resulting in chlorosis and leaf-yellowing.

 
Varieties
Since rambutan is a cross-pollinated crop, large genetic variation has occurred in nature over generations and numerous varieties have been identified but their nomenclature is confused. Most of them can be distinguished by spine length, fruit wall colour, aril thickness, aroma, adherence of aril to the seed, vitamin C content and fruit set. Rongrien and Chompu are most popular varieties in Thailand. Both these have crisp arils and are well-suited for canning and for fresh consumption. Bingjai, Lebak Bulus and Rapiah are important varieties of Indonesia, which have sweet, sub-acid and very sweet pulp respectively. Bingjai has long spines while Rapiah fruits are smaller. Some of the good varieties like Azimal (thick aril, sweet to sub-acid pulp), Kelip (medium thick aril, very sweet) and Singapura (thin aril, very sweet) are grown in Malaysia. Trees with male, female and perfect flowers are known in rambutan, but most of the cultivated varieties are generally monoecicus, bearing male and female flowers on the same tree.
   
Propagation

Most of the varieties as mentioned above are of seed origin, but scientifically use of seeds for propagation is discouraged in rambutan culture for two reasons: the progeny varies with uncertain performance and occurrence of both male or female trees. The male trees not producing a crop while the female trees require pollinator to bear well. Hence, vegetative propagation is advocated to maintain the genetic integrity of a variety.

For rootstock purpose, fresh seeds are planted in humus-rich medium with good drainage. Seeds germinate in a fortnight. At 3–4 leaf stage, the seedlings are transplanted to polybags with minimum possible damage to roots. The seedlings are ready to bud when the stem has attained a diameter of about 15 mm. Sometimes due to iron deficiency rambutan seedlings show chlorosis (yellowing of leaves) which should be corrected immediately by appropriate soil amendments. The modified Forkert (modified patch budding) using mature budwood, and approach grafting or inarching are the standard techniques used in propagation. It is also clonally multiplied through air-layering in India, Malaysia and Indonesia.

   
Cultivation  

Planting

Generally a spacing of 10m between trees is recommended, but this can be modified depending on soil fertility and growth habit of the cultivar.

Pruning

An ideal rambutan tree should have a wide crown with the main branches well separated, and the interior should be free from dead, diseased, broken branches and suckers. Like litchi, rambutan produces its fruit near the periphery of the crown, hence one should go for a minimum pruning.

Irrigation

In case of insufficient rains or long gap, trees may be irrigated either by cannals or by drip depending upon feasibility and the available facility. Long dry season induces flower drop.

   
Harvesting & Postharvest management

Vegetatively propagated trees have shorter juvenile phase and start bearing when about 4 years old, whereas the seedlings take 6–7 years. Fruits require 4–5 months to develop and reach harvestable stage. In southern Asia, fruits are harvested during July–September and December–February, July–September being the main season. All the fruits in a cluster come to harvest at the same time, making it possible to pick the whole cluster. Harvesting is done using secateurs or a long pole with a hook on one end. Damage to the branches while harvesting should be avoided, as these are the sources of next crop. Rambutan trees are quite productive and a yield of about 150 kg/tree can be expected. But it shows a tendency for alternate bearing.

The fruits should be kept under shade. Fruits are graded based on size and degree of ripeness. Then they are washed and dried before packing. Fruits of good quality are selected and packed by placing them in a ventilated box or case of
60cm × 28cm × 28cm.

The usual juicy aril around the seed is eaten, which can be separated from the seed in case of the free-aril varieties. Besides use as fresh fruit, rambutan fruit is also processed to increase added value. Several products like jam, jellies, rambutan cocktail, rambutan sweets and canned rambutan are prepared from its arils but much of the flavour of the fresh fruit is lost. Rambutan sweets are used for pie (as raisin), ice-cream and fruit ice. Sometimes arils are canned by stuffing with pineapple in heavy syrup.

Nutritional Value
 
Usage
Food use
 
Rambutans are most commonly eaten out-of-hand after tearing the rind open, or cutting it around the middle and pulling it off. It does not cling to the flesh. The peeled fruits are occasionally stewed as dessert. They are canned in syrup on a limited scale. In Malaysia a preserve is made by first boiling the peeled fruit to separate the flesh from the seeds. After cooling, the testa is discarded and the seeds are boiled alone until soft. They are combined with the flesh and plenty of sugar for about 20 minutes, and 3 cloves may be added before sealing in jars. The seeds are sometimes roasted and eaten in the Philippines, although they are reputedly poisonous when raw. 
 

Non-food uses

 

Dye uses: young shoots are used as a green dye for silk that has already been dyed yellow with turmeric. The fruit walls are used, together with tannin-rich parts of other plants, to dye silk black after a preliminary red staining. Leaves are used, together with mud, as an impermanent black dye.

Seed fat: the seed kernel can be used for the production of rambutan tallow, a solid fat similar to cacao butter, which is edible and also used for soaps and candles. When heated, it becomes a yellow oil having an agreeable scent. Its fatty acids are: palmitic, 2.0%; stearic, 13.8%; arachidic, 34.7%; oleic, 45.3%; and ericosenoic, 4.2%. Fully saturated glycerides amount to 1.4%. The oil could be used in making soap and candles if it were available in greater quantity. The seed itself is edible (after roasting) but is bitter and narcotic. The wood is suitable for general construction. The tree is very ornamental when it fruits.

Wood: The tree is seldom felled. However, the wood–red, reddish-white, or brownish–is suitable for construction though apt to split unless carefully dried.

Medicinal Uses: The fruit (perhaps unripe) is astringent, stomachic; acts as a vermifuge, febrifuge, and is taken to relieve diarrhea and dysentery. The leaves are poulticed on the temples to alleviate headache. In Malaya the dried fruit rind is sold in drugstores and employed in local medicine. The astringent bark decoction is a remedy for thrush. A decoction of the roots is taken as a febrifuge.

 
Toxicity
 

There are traces of an alkaloid in the seed, and the testa contains saponin and tannin. The seeds are said to be bitter and narcotic. The fruit rind also is said to contain a toxic saponin and tannin.

 
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Chromosome Number: 26
Taxonomic Classification
Class
:
Magnoliopsida
Order
:
Violales
Family
:
Cucurbitaceae
Genus
:
Luffa
 
Ridge gourd or ribbed gourd is also a monoecious viny vegetable. It is mainly cultivated in Andhra Pradesh, Tamil Nadu, Karnataka, Gujarat, Assam, West Bengal and Konkan region of Maharashtra.
   
Climate and soil  
It grows very well in a warm hot climate, the optimum temperature being 25°–30°C. Very high temperature especially in the early crop growth stage (more than 38°C) helps produce more male flowers, reducing the yield. Very low temperature also affects growth of vines. Sandy loam soil, rich in organic matter is most-suited for higher yield. Proper drainage is highly beneficial.
 
Varieties

There are a number of improved varieties, some of which are described below.

Co 1

Fruits are 45–50cm long with broader stylar-end than stalk-end and green in colour, each fruit weighing 700g at harvestable maturity. Yield 140q/ha in 125 days.

Co 2

Super long fruits (90–100cm), each weighing 800g. Yield 250q/ha in 120 days.

PKM 1

Fruits 70–80cm long, club-shaped. Yield 160–180q/ha in 130 days.

Pusa Nasdar

An early variety with light green, medium-sized club-shaped fruits. It flowers in 60 days. About 15–20 fruits are borne on each vine.

Satputia

Vines produce bisexual flowers instead of male and female flowers separately. Fruits are borne in clusters.

   
Cultivation  

Sowing

June–July is the sowing time for kharif crop, while February–March for summer crop. The field should be ploughed 3–4 times. Add farmyard manure @ 10 tonnes/ha. Long, raised beds are formed with furrows 50–60cm wide. The seeds should be sown on both the edges of the beds. In each hill, 3–4 seeds are sown. Retain only 2 healthy seedlings 2.5m × 1.0m apart. In south India, pits of 45cm × 45cm × 45cm are dug and filled with farmyard manure and top soil. About 4–5 seeds are sown in each pit. Thus 4kg seed is enough for one hectare. For raising seedlings in polybags, about 1.5kg seed is sufficient to plant one hectare crop.

Interculture

A dose of 15–25kg N, 30–40kg P and 30kg K should be applied before sowing or planting. The seedlings should be sprayed with Ethrel (250ppm) 4 times starting from 2-leaf stage at weekly intervals to encourage production of female flowers. It should be irrigated once a week depending on soil moisture. Apply 15–25kg N/ha 30 days after sowing. The vines should be trained on a bower with the help of a thin bamboo pole used as a stake. During weeding and hoeing earthing-up of the vine should be done. 

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Chromosome Number: 14
Taxonomic Classification
Class
:
Magnoliopsida
Order
:
Rosales
Family
:
Rosaceae
Genus
:
Rosa
 
Rose is the most ancient and popular flower grown the world over. It is a versatile plant adapted to varying climatic conditions. In India, it is cultivated commercially for cut flowers, both for traditional flower market and contemporary florist shops. Rose flowers without stem and loose flower petals are used in traditional markets for making garlands, for offering in temples, while the florist shops sell cut roses with stems mainly for bouquets and floral arrangements. In recent times, about 60 units have been established under joint ventures around Bangalore, Pune, Nasik, Mumbai, Hyderabad, Gurgaon (Haryana), Chandigarh and Saharanpur (Uttar Pradesh) for growing roses in greenhouses for export of flowers to Japan, Holland, Germany and other European countries. Besides, the Damask rose (R. damascena) and Edouard rose (R. bourboniana) are cultivated for rose attar and other products, gulkand, gulabjal and pankhurj. The rose is grown in about 6,000 ha area. Karnataka, Tamil Nadu, Maharashtra, Bihar, West Bengal, Uttar Pradesh, Gujarat, Haryana, Punjab, Jammu and Kashmir, Madhya Pradesh and Andhra Pradesh are major rose-growing states.
   
Climate and soil  

The cultural practices described here are only for growing roses in the open. Recently several units have been established for growing roses in greenhouses under joint ventures or on foreign consultancy. However, the agro-technology adopted in greenhouse is quite variable.

Roses are grown in cold climate of the hills as well as in the plains of northern and southern regions. Some of the best quality roses can be produced in the open in the cool season of northern plains like Chandigarh, Ambala, Patiala, Jaipur, Ajmer, Udaipur, Delhi, Meerut, Lucknow, Saharanpur, Dehradun. In eastern India, roses do well around Ranchi, Patna, Jamshedpur, Calcutta, 24 Parganas, Nagpur, Pune, Nasik, Indore, Bhopal and Gwalior. In south, Bangalore, Hyderabad which have a mild climate, roses grow quite well and flower over a longer period.

Well-drained, medium loam soil having a pH of 6.0–7.5 is ideal for rose growing. Heavy clay soil is not suitable for roses. There should be soft muram below 45–60m layer of soil for a good plant growth. The plants do not thrive in saline sodic soils.

 
Varieties
Modern roses grown in gardens are Hybrid Teas, Floribunda (also Grandiflora), Polyantha, Climbers and Ramblers, Miniatures and Shrub roses. However, in the cut flower trade, the rose varieties are classified as large-flowered, small-flowered and spray types. There are 20,000 or more rose cultivars in the world. About 250–300 new varieties are added every year. The International Registration Authority of Roses is located in the USA which registers the newly evolved roses in the world and lists them in the book "Modern Roses" which is updated periodically. In India, the National Registration Authority of Roses under the International Registration Authority, is at the Indian Agricultural Research Institute, New Delhi, which undertakes registration of newly evolved Indian rose cultivars.
   
Propagation
Hybrid Tea and Floribunda roses are generally propagated by budding, whereas climbers, ramblers, polyanthas and miniatures can be multiplied by stem cuttings. In West Bengal, inarching is also practised to multiply roses. The commonly used rootstock for budding is Edouard rose (R. bourboniana) in northern plains and R. multiflora in coastal areas, West Bengal, Bihar, Karnataka, Maharashtra, Andhra Pradesh, Tamil Nadu and sub-mountainers regions of Dehra Dun and Nainital (Uttar Pradesh). Another rootstock Rosa indica var. odorata has now become quite popular in northern plains. It is tolerant to powdery mildew and high soil pH. A few other rootstocks—Dr Huey, R. canina, R. laxa, R. manetti, R. rugosa, R. fortuniana and "Thornless"—are not better than the commonly used rootstocks. The rootstocks used in India are propagated by stem cuttings. December–February is ideal time for budding (T-budding) in northern plains; October–November and January–March in the eastern region; February–April (or any other time) in Bangalore and Pune, and February–March/April in the hills.
   
Cultivation  

Planting

Roses require full sunlight or light at least for 6 hours preferably in the forenoon, if not during the whole day. Protection from strong winds is also necessary. The rose beds in the garden should be away from trees or hedges and well-drained as the plants do not thrive in a wet or waterlogged soil.

The beds should be dug deep during summer and the open soil kept exposed to sun. It helps kill weeds, insects and other organisms present in the soil. About 2 tonnes of farmyard manure or cowdung manure along with 2kg superphosphate and 1kg BHC (5%) dust may be incorporated into the soil and bed levelled followed by watering/irrigation. The bed must be properly levelled and there should be no waterlogging in beds.

Generally, rose beds are rectangular but these may be oval, circular or of irregular shapes depending upon garden design. It is always better to plant roses in beds than growing these individually. If there is more than one bed in the garden, it is better to plant only one variety in a bed. If it is not possible, more than one variety may be grown in a bed, preferably of the same flower colour. The Hybrid Teas and Floribundas may be planted in separate beds as far as possible. While grouping the varieties in a bed, tall varieties should be put in the back row while dwarf ones in the front and those having intermediate plant height in the middle row. It is necessary to have harmonious and pleasing colour combinations if varieties have different flower colours.

The rose should be planted in pits of 60cm diameter and 60–75cm depth dug at appropriate distances in a bed. The distance of planting varies according to the type of rose. The Hybrid Teas and Floribundas are planted 75cm apart. A closer planting distance of 30cm × 60cm is ideal for obtaining cut flowers. Miniatures and polyanthas can be planted at a closer distance of 30cm and 45cm apart respectively. The standard roses are planted 1–1.5m apart while the distance for climbers may be 2–2.5m. About 7–10 days before planting, 8–10kg of cowdung manure/ farmyard manure/compost and bone-meal or superphosphate (225g) may be added to the soil in each pit. If the soil is heavy (clay), mix coarse sand in it to make it more porous. While planting the budded plants, the bud union is kept slightly above the ground level.

In northern plains, mid-October is good time for planting. But it can be planted up to February. However, later planted bushes do not produce good flowers and the flowering is delayed. Roses may be planted from October to December and late-May to June in Karnataka and Maharashtra states. September–December or even up to February is ideal planting time in the eastern plains of Bihar and West Bengal. In northern hills, the planting may be taken up in October–November or March–April. As a general rule, planting should not be done in either very hot weather or during heavy rains.

Pruning

The rose bushes are pruned once a year during second or third week of October in the northern plains. After about 6–7 weeks of pruning, the plants start flowering. The time of flowering can be adjusted according to the date of pruning. The new or so-called "Maiden" plants are not pruned. These are generally tipped lightly before planting. In the old hybrid tea bushes, the previous season's thick shoots are pruned up to half the length, keeping about 5 or 6 eyes on each stem. A slanting cut is made a little above an eye which is facing outwards. The Floribundas are pruned moderately. The climbing and rambling roses do not require any pruning, except the removal of unhealthy, dead and interlaced twigs. The Polyantha roses are pruned lightly, whereas the miniatures are generally not pruned. Hard pruning of Hybrid Tea and Floribunda, keeping only 3 or 4 shoots with 3 or 4 eyes from the base is practised for obtaining exhibition blooms. While in the northern plains, the pruning is done in October, it is practised during late-October to early-November in West Bengal, November-end to early-December in Chennai, March–April in the hills, and twice a year during June and November in Bangalore and Pune. The pruning of Rosa damascena is generally done from December to mid-January for obtaining early flowering and higher flower yield.

Manuring and fertilization

Rose being a perennial crop, it requires regular nutrient feeding through manures and fertilizers at the time of pruning, plant growth and at the end of flowering, besides during land preparation and planting of new bushes. The clay and sandy soils require more manures than the loam soil. The nutritional requirement of rose plants vary with the type and fertility of soil, cultivar and age, size and vigour of plant.

Farmyard manure, compost and cowdung manure are commonly used manures and are applied before planting new bushes and at the time of pruning. After pruning, the soil in the bed is dug up with a fork with due care to avoid any damage to the roots. About 8–10kg or 6–8kg of well-rotten cowdung manure should be applied to each plant depending upon its age and size, and type of soil followed by copious watering of plants.

Oil cakes, preferably neem cake or castor cake @ 50g/plant or 15kg/ 100m2 is applied at the end of the first flush of flowering. Poultry manure or sheep/goat droppings, can be applied @ of one litre/plant. The oil cakes are quick acting organic manures, as their N becomes available to plants within a week of their incorporation in the soil. Farmyard manure or cowdung manure may be used if oil cake is not available.

Though it is not possible to follow any common fertilizer mixture in all regions, there are some fertilizer combinations suitable for many areas. A few fertilizer mixtures are commercially available in the market. However, fertilizer mixture having 1 part of urea, 3 parts of superphosphate and 2 parts of potassium sulphate is ideal. About 40g of this mixture may be applied as topdressing to each plant 3 times at 15 days intervals after pruning. The fertilizer mixture should not be stored for a long time. It is better to prepare it at the time of application. A topdressing of the fertilizer mixture may be given again in January–February after the end of the first flush of flowering in northern plains, similarly in other milder areas fertilizer application may be practised after each flush of flowering.

Fertilizers can also be applied through foliar spraying. It is quite effective in roses. About a month after pruning, foliar spraying may be taken up and repeated at 7–10 days intervals. It should be stopped when the flower buds start opening. It must not be done in hot weather. A foliar spraying of urea (1.25g) and potassium dihydrogen phosphate (1.25g) mixed in one litre of water is recommended for roses. To add a spreader like surf or any other detergent soap is obvious. Foliar application of urea alone (0.2–0.3%) in water is also useful. It can be applied mixed along with an insecticide like Malathion or Rogor.

Foliar application of micronutrients, eg. iron, magnesium and manganese corrects the deficiency of these elements. The spray solutions may be prepared by adding ferrous sulphate (2g) and slaked lime (1g) in one litre of water, magnesium sulphate (2–3g) in one litre of water and manganese sulphate (2g) and slaked lime (1g) in one litre of water. These foliar solutions may be sprayed separately for correcting deficiencies of iron, magnesium and manganese. A mixture of manganese sulphate (15g), magnesium sulphate (20g), chelated iron (10g) and borax (5g) added to 25 litres of water (concentration 2g/litre) is also effective.

The application of liquid fertilizers to rose plants growing in the open is not necessary if adequate quantities of appropriate fertilizers have been provided to them.

Irrigation

The frequency of irrigation depends upon the soil texture and climate. Watering is more frequent in sandy soils and hot weather than in clay soils and humid/rainy or cool season. During the rainy season in eastern/southern or coastal areas it may not be necessary to irrigate the plants. The frequency of watering during summer may be about twice a week while in winter or cool season it may be only once a week or 10 days. The rose beds should receive well-spread water but no waterlogging. Heavy watering at comparatively long intervals is more useful than frequent light watering. Drip irrigation is useful. Sprinkler irrigation should be avoided as it encourages infection of leaf diseases and often exposes the feeder roots of plants.

Weeding

Generally hand-weeding is practised. Monocot weeds can be effectively controlled with Glyphosate (1.0kg/ha) and dicot weeds with Oxyfluorfen (0.5kg/ha) as pre-emergent treatment. A solution of Simazine (0.2%) and 2, 4-D, (0.05%) applied as pre-emergent spray is also useful.

Mulching

Rose beds may be mulched with straw, black polyethylene film, saw-dust and well-rotten farmyard or cowdung manure. It helps conserve soil moisture, suppress weeds and produce more flowers of better quality.

Disbudding and pinching

The young vegetative bud in the leaf axils of basal and lateral shoots are disbudded to encourage branching at the base and to obtain long terminal shoots. For obtaining long stemmed quality blooms, it is necessary to do disbudding and pinching or removal of side flower buds. In Hybrid Teas often there is a terminal flower bud along with 2 smaller side buds. It is, therefore, necessary to remove the side buds so that the terminal flower bud produces quality bloom.

Suckers

The shoots or suckers of the rootstock emerging from the base of the plants should be removed as soon as they appear. They can be distinguished from those of the scion by the shape and size of their leaves.

   
Harvesting & Postharvest management

The rose flowers are cut while still in the bud stage after the sepals curl back and the colour is fully showing. In large-flowered roses, flowers along with the stem of prescribed length are cut when the first one or two petals start to unfold but do not open fully. The flowers in small-flowered clustered varieties are cut when these begin to open in the cluster.

In foreign market, the size of stem varies from 60–90cm for large-flowered roses and 40–50cm for small-flowered ones depending upon the grade. The size of large-flowered bud is 3–3.5cm and 2–2.5cm for the small-flowered.

The flowers are harvested in early morning or late in the afternoon. The cut roses are kept in plastic buckets/containers filled with clean water having disinfectant and preservative (silver thiosulphate) to enhance their shelf-life. These flowers are shifted to precooling chambers having a temperature of 10°C, and kept there for about 12hr. The grading is done on the grading tables which have graduations marked on them. Automatic grading tables are also available. The flowers are graded for their stem length, quality and variety. The defective, damaged or bruised flowers are rejected.

The graded flowers are bunched with 10 or 20 stems in each bunch and sleeved with thick paper or plastic film. These flowers are then packed in telescopic corrugated cardboard boxes of specified dimensions. The box size may be 105cm × 45cm × 20cm for containing 200–300 stems, each of 40–50cm length and 135cm × 35cm × 20cm for 200–300 stems, each of 60cm–90cm length. The flower boxes are kept in cold storage at 2°–4°C temperature for 12–24hr. Nowadays the cut flower boxes are pre-cooled through vacuum cooling at 2°–4°C in much shorter time of about half an hour. The flower boxes are then transported to airport in refrigerated trucks. Efficient logistics management after flower production is important for export consignments, which may include detailed planning of transportation by road and aircraft, maintaining effective cold chain, quarantine, customs and airline formalities and minimum time lapse in loading the flower boxes in the aircraft for direct flight to destination. 
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Rose geranium or scented geranium is an aromatic perennial herb. It is grown in cooler, subtropical climate of Mysore and Bangalore (Karnataka), and extended to Hyderabad (Andhra Pradesh). Its oil has a refreshingly delicate long-lasting rosy odour with fruity under-note, containing 66–78% primary alcohols (rhodinol). It is used in manufacturing of perfumes, creams, talcum powder and body lotion. It is stable in alkaline medium and is therefore used for scenting of soaps. China, Egypt, Re Union Islands, and Malagasy Republic are major producers and exporters of its oil, whereas Algeria and Morocco also maintain sizeable plantations. We import part of our requirement annually.

Rose geranium is a bushy plant with cylindrical stem and large cordate-ovate deeply lobed pubescent leaves. The plants grow up to 1m in height under cultivation. In hills, it flowers in February–March and September. These are bisexual, pentamerous flowers with pink corolla and pale-yellow shrivelled anthers, devoid of pollens. They drop out soon, producing no seed. There are 2 genotypes suitable for cultivation in India. Algerian type forms slender, erect plants with dark pink flowers. From this, PG 7 is selected for growing in hills. It contains 0.3% oil with 57% l-citronellol. The other culture, Re-union type , produces more bushy growth with light pink flowers. It grows well at lower elevation but it is more susceptible to wilt. It gives oil at par but the oil has marginally higher l-citronellol (59.4%) content. An Egyptian culture has recently been introduced in the country. It is drought hardy, tolerant to high summer temperature and relatively more tolerant to wilt disease. It grows well on lateritic soils around Hyderabad in Andhra Pradesh.

Geranium flourishes well over deep, well-drained, slightly acidic fertile sandy-loam to clay-loam soils under mild subtropical to subtemperate climate. It can withstand drought but its yield is reduced. The plants are raised in nursery during early spring from 8–15cm long terminal stem-cuttings possessing 2–4 nodes each. These should be treated with Bavistin (0.1%) for 10 seconds. The cut ends are dipped in IBA solution. A nursery area of 80m 2 is sufficient to plant a hectare land. Raised nursery beds are laid out in 3m × 1.5m size. The plants produce roots and 3-week-old sprouts are ready for planting. The field is prepared to a fine tilth. A dose of 2.5–4 tonnes of farmyard manure is added at land preparation. The rooted plants are planted at 60cm × 45cm or 60cm × 60cm spacing followed by a light irrigation. The plants respond to medium doses of chemical fertilizers. A fertilizer dose of 60, 60 and 40kg of N, P and K/ha is given. However, application of 100–120kg of N/ha in 3–4 split doses is ideal. Application of 20kg of Bo in Kodai hills, 20kg of Cu and 30kg/ha of Mo in Palney hills are better for getting higher yield. Since the crop grows slow initially, it is occasionally grown as a catch crop in plum, peach and pear orchards.

Intercropping butter bean during first year in the hills produces 1.2 tonnes/ha of beans as bonus crop. The crop is given 1–2 hoeings and weedings when the rows close up and plants grow tall and bushy. The pruning of branches helps induce bushy growth. Irrigation is given at 10–15 days interval during summer depending upon soil and atmospheric humidity.

The first crop is harvested 6 months after planting. Thereafter, 3–4 coppicings are taken annually. It is harvested when basal leaves turn yellow and on pressing fresh leaves emit a rose-like odour. The leaf blades contain maximum oil, followed by petioles; the woody stem has negligible quantity. The plants are coppiced at top in early morning on sunny days including branches, leaving a few leaves. Generally 4 harvestings are taken in the second year and, thereafter, at 3 months intervals—January, April, July and October. The average yield in hills is 15–18 tonnes/ha of fresh herbage, containing 1.5–2.0% oil on commercial distillation. Most farmers obtain 15kg of oil/ha by employing of hydro-distillation units. However, under good management, 25 tonnes/ha of fresh herb and correspondingly higher oil yield may be obtained. Its yield in plains of Bangalore is around 40 tonnes/ha or 40kg of oil, whereas the Egyptian culture produces 60 tonnes/ha, yielding 60kg of oil in well-irrigated commercial plantations. Air-drying and withering of herb in shade for 10–12hr before distillation improves oil recovery due to possible action of enzymes. The quality of oil improves 1–2 years after storage. The oil should be stored in air-tight aluminium containers, filled to the brim and kept in cool dry places. 

   
 
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Chromosome Number: 24
Taxonomic Classification
Class
:
Magnoliopsida
Order
:
Violales
Family
:
Cucurbitaceae
Genus
:
Citrullus
 
Round melon also known as round gourd, Indian squash, squash melon, or tinda is an important summer vegetable cultivated extensively in north India. Its immature fruits are cooked as vegetable. The fruits at cooking stage contain 1.4% protein, 0.4% fat, 3.4% carbohydrates, 13mg carotene and 18mg vitamin C/100g fresh weight. As its fruits contain high proportion of water, their consumption gives cooling effect to the body. The fruits are also considered good for dry cough and for improving blood circulation in the body.
   
Climate and soil  

It grows well under warm and dry climate but can be grown both under hot as well as mild climates. The temperature of 27°–30°C is optimum for seed germination. Seeds do not germinate at low temperature. Therefore, roundmelon cannot be grown in seasons and areas with low temperatures.
Sandy-loam soils rich in organic matter are ideal for its cultivation. It gives a good crop in river-beds also but in the lower beds towards water stream where watertable is quite high. While growing in field soils the drainage must be ensured. A pH between 6.0 and 7.0 is ideal for its cultivation.

 
Varieties

There are several locally-grown cultivars in different areas. A few varieties have been released. These are described below:

Arka Tinda

This is an early-maturing variety. Its fruits are round, light green with soft hairs and tender flesh. It yields around 90–100q/ha in 90–100 days.

Tinda Ludhiana

Its plants are vigorous bearing 8–10 fruits/vine. Fruits are medium in size, flattish-round and light green. The fruit surface is shiny but pubescent. The flesh is less seedy, white, tender and good in cooking quality. It yields 45–60q/ha. The fruits become ready for picking 60 days after sowing.

Tinda Tonk

Its fruits are green, medium-sized with hairs. Plant spread is normal. It is grown both as solo and as an intercrop. It yields 60–75q/ha taking 65–70 days to first picking.

Tamil Nadu Selection

Its plants are vigorous with broader and dark green leaves. The fruits turn flattish towards seed maturity. It may be cultivated in spring-summer and kharif seasons.

   
Cultivation  

Planting

Since it is a short-duration crop, it is planted in different seasons in different parts of the country. In north Indian plains, 2 crops are taken. First crop is sown during February–March, where as second during June–July. In western India, summer crop is sown in December–January and rainy season crop in July–August. In south India, it can be sown in December–January and rainy season crop in June–July. In hilly regions of north India sowing is done in May–June and could be continued up to July.

Seed can be sown on raised sides of furrows or in pits. Two seeds/ hill on both inner sides of furrows and 4 seeds/ pit are sown. About 3.5–7.0kg seed is enough for sowing a hectare crop depending upon variety, season and climatic conditions. It could also be cultivated as an intercrop with cotton, maize and millets.

A plant spacing of 150–200cm between furrow and 50–60cm between plants is recommended. However, a spacing of 250cm × 90cm is optimum for summer crop if sowing is done on one side of furrows in Punjab. And a spacing of 150–200cm between rows and 60–120cm between plants or hills is recommended for Bangalore like conditions.

Manuring and fertilization

Roundmelon responds well to organic manures. The application of farmyard manure @ 20–25 tonnes/ha should be done at the time of field preparation. A dose of 50kg N + 100kg P + 50kg K/ha as basal dressing + 50kg N as topdressing 40–45 days after sowing is essential for a healthy crop. Higher dose of N improves vegetative growth and decreases yield.

Interculture

Frequent hand-weedings should be done to keep the crop weed-free. First weeding may be given 15–20 days after sowing and later weedings when required. Use of black polythene mulch helps conserve soil moisture and suppress weeds. Selective herbicides like Nitrofen (1.25 litre/ha) and Alachlor (2.5 litres/ha) could also be used to keep weeds under control.

Irrigation

Pre-germinated/soaked seeds germinate in 5–6 days. First irrigation should be given at the time of seed germination. Later irrigation could be given at 5–8 days interval depending upon soil type and climatic conditions. Roundmelon needs more frequent irrigation than other cucurbits because of its shorter root length. During rainy season irrigation is generally not required. Drip irrigation is also useful as it improves fruit yield by 28%, reducing water requirement compared with furrow system.

   
Harvesting & Postharvest management

It takes 60–90 days from sowing to first fruit picking depending upon the cultivar and season. Fruits reach edible maturity 6–8 days after fruit-set. Picking should be done when these are still immature and small in size. Large-sized fruits are not liked in the market even if immature and soft. Therefore, picking should be done at every third to fourth day. The first formed one or two fruits at basal nodes should be harvested/ nipped early to allow better vine growth so that the plant can bear more number of fruits later.

A good crop can give 80–120q/ha green, unripe fruits. Plant growth-promoting chemicals also influence the yield. Maleic Hydrazide (50ppm) aqueous solution sprayed at 2 and 4 leaf stage stimulates vine growth, giving more femaleness and enhance female flowering at lower nodes. All these factors improve yield by 50–60%.

Keeping its fruits in cool environment without causing bruises to their surface could help in keeping fruits for 3–4 days with frequent wetting of covering/packing material and keeping the produce under shade or cool temperature. After harvesting, fruits should be carried in smaller lots to avoid bruising during handling.

All deformed and damaged fruits should be sorted out and rejected. Healthy fruits should be graded according to their size. Graded fruits fetch higher price. The produce is then packed in baskets with some filler, preferable leaves with soft texture and low moisture content. For distant markets, even perforated cardboard boxes with fillers are used. For local market, jumble packing in baskets or gunny bags is done and water is frequently sprinkled to keep the packing cover wet and cool. Since fruits respire and liberate heat, there should be enough aeration between the fruits and the warm air should go out otherwise the fruits turn pale and become unmarketable. For transporting, rack system should be preferred rather than dumping in a truck or heaping in the carriage. Due to high water content, the fruits are likely to get spoiled early, therefore fast transportation and quick disposal/consumption should be kept in mind.

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Chromosome Number: 36
Taxonomic Classification
Class
:
Magnoliopsida
Order
:
Malpighiales
Family
:
Euphorbiaceae
Genus
:
Hevea
 
Rubber is commercially-viable source of natural rubber, an essential industrial raw material. From its native habitat in the Amazon valley, this crop was introduced to South Asia through Kew garden in the U K in the late 1870s. Today rubber is grown extensively in Indonesia. Thailand, Malaysia, Chaina, India and Sri Lanka cover an area of about 8.5 million ha. India ranks fifth and fourth in total area and production. In productivity India ranks first in the world. Even before the beginning of formal cultivation of rubber as a plantation crop in the 19th century, it had already become popular in Europe. With more than 35,000 different kinds of products ranging from automobile tyres to pencil erasers that are manufactured from latex and natural rubber, no single plant species has influenced human life as Hevea has. We cannot think of a world without natural rubber. An important reaction of natural rubber is its combination with sulphur (vulcanization) during which the plastic properties of raw rubber are converted to elastic properties. And hence vulcanized has high tensile strength and comparatively low elongation. About 60% of all rubber consumed in developed countries is for automobile tyres and tubes. In addition to tyres, a modern automobile has more than 300 components made out of rubber. Many of these are manufactured from natural rubber. In India this crop is mostly cultivated along the strip of land between the Arabian sea in the East and Western Ghats in the west extending about 400km from Kanyakumari district of Tamil Nadu in the south and Karnataka in the north. In addition, rubber cultivation is being extended to the north Konkan and in north-eastern states where the agroclimatic conditions are less congenial.
   
Climate and soil  

Although its natural habitat is situated in the warm and humid tropics, rubber is very versatile in its adaptation to a wide range of agroclimatic and soil conditions. An annual rainfall of 2,000–4,000 well-distributed throughout the year, fairly high atmospheric relative humidity (80% or above) and warm and sunny days (more than 6 hr sunshine/day throughout the year with an atmospheric temperature of 21°–35°C are ideal for its growth. A minimum of 125cm soil depth with slight or moderate acidic pH and a gentle slope is needed. Laterite and lateritic types and red and alluvial soils are suitable. In India, traditional rubber-growing regions have ideal agroclimatic and soil conditions.

The Konkan region, Coromandal coast in the east, north-western West Bengal, north-eastern states and the Andaman and Nicobar Islands are potential non-traditional areas. The agroclimatic conditions of these areas are not so ideal as in the traditional regions. Nevertheless this crop can be successfully grown in these areas with a suitable location-specific agro-techniques. for example, in the north Konkan, there is severe and prolonged drought and high temperature in summer which stretches from January to June. During this season, the mean maximum temperature can be as high as 37°C which often goes beyond 40°C and the atmospheric relative humidity can be as low as 40%. With a minimum life-saving irrigation and water-conservation practices rubber has been successfully cultivated in this region. In contrast, the north-eastern parts of the country have very severe winter. Here the mean minimum temperature is 11°C and the mean maximum temperature is 26°C in the winter. The minimum temperature goes as low as 5°C occasionally. But there are certain clones of Hevea that can grow well here.

Apart from the adverse agroclimate, the soils in the non-traditional regions are highly depleted in essential nutrients, organic carbon etc. While in the traditional regions this crop is cultivated in the plains and gentle slopes along the Western Ghats, in non-traditional region it is cultivated even 600m above mean sea-level.

 
Varieties

Clones

In the earlier days plantations were raised from the unselected and highly cross-pollinated heterogeneous seeds. These seeds, called clonal seeds are collected from seed gardens established mainly in the Kanyakumari district of Tamil Nadu. The mature seeds are shed in July/September. The yield potential of trees grown from these seeds is rather poor. Hybridization and selection work on Hevea have since produced several high-yielding clones and almost 95% of the area under rubber is cultivated with these elite clones. Due to the extremely cross pollinated nature of this tree species no pure lines or varieties are available.

The Rubber Board of India has approved 3 categories of clones for cultivation in the country. They are:

Category 1: RRII 105, PB 260 (RRIM 600 and GT1 only for non-traditional areas).

Category 2: RRIM 600, GT1, PB 28/59, PB 217 AND RRIM 703.

Category 3: There are a number of promising clones . Clones of Category 1 can be planted with confidence. However, it may not be wise to adopt a single clone for cultivation in large areas, because if a disease or pest epidemic occurs, the entire plantation may be wiped out. Hence a blending of different clones is advisable. The hybrid clone RRII 105, is the highest-yielding in the world. It has become very popular, occupying 80% of the area under rubber. Its average yield is 2,400kg/ha/year.

   
Propagation

Propagation is almost entirely through bud grafting of modern high-yielding clones. For bud grafting, unselected polyclonal seeds are germinated in special germination beds made of river sand (5cm thickness) with convenient size and shape and 90cm width. The beds should be raised 10–15cm above the ground level and partial shading should be given. Seeds should be sown as soon as they are collected. The germination beds should be kept moist throughout the day and may be covered with loose coir mating or gunny bags to avoid extreme dry and wet condition. Germination starts within 6–7 days. Germinated seeds should be picked out when the roots are just emerged and planted in the field or in the nursery.

Nursery is developed on well-drained, plain land by digging the soil and cleaning it. Beds are prepared of 60–120cm width and convenient length. Germinated seeds are then sown at 23cm × 23cm or 30cm × 30cm or 34cm × 20cm. Regular plant-protection measures, weeding, mulching, partial shading and regular watering during summer are important.

Bud grafting is done on the seedlings when they are 2–8 months old using green or brown dormant bud patch collected from selected scions clones. Brown buds are collected from budwood of about 1 year age and grafted on to the seedlings that are about 10 months old. For green budding, seedlings of 2–8 months old and with green stems are used as stocks to graft green buds collected from leaf axils of budwood that is 6–8 weeks old. Transparent polythene tapes are used for bandaging the grafted portion for 3–4 weeks by which time the graft is firmly united. Later the seedling stem is sawn off above the graft union and the grafted bud will start to sprout in a couple of weeks. The budded stumps can be either planted directly in the field or grown in polybags (55cm length, 25cm width and 400 gauge thickness) for one year under nursery conditions and then transplanted into the mean field with the onset of the south-west monsoon. Fairly heavy clay-loam soil is used to fill the polybags.

Alternatively, sprouted seeds could be sown directly in the field, seedlings raised and bud grafting done there itself. But, management is much easier if the bud grafting is done in the nursery and the budded plants are allowed to grow for one year in the nursery before transplanting them into the main fields. This will also allow the planter to select the best and uniform plants for field planting.

   
Cultivation  

Planting

Planting season starts with the first rains received just before the south-west monsoon. Square or rectangular planting is adopted on flat land and contour planting with continuous terracing on hilly slopes. Soil and water conservation techniques should be followed during first year itself. In the subsequent years, particularly after the canopy has closed almost no tillage is needed inside the plantations.

The planting density should be around 420–445trees/ha in budded plants and 445–520trees/ha in seedlings. Any gap may be filled up during second year subsequent which no gap filling is feasible. Mulching the plant base with dry leaves or grass cuttings and shading the plants are good practices during summer particularly in the early years of growth.

Pits of 75cm × 75cm × 75cm or 90cm × 90cm × 90cm size are filled with top soil. When stumps are planted, it should be done as soon as they are pulled out of the nursery beds. If a budded stump is planted, the bud union should be just above the ground level. When polybag plants are used, ensure that the top whirl is fully mature to withstand the transplanting shock. Dressing of the coiled or damaged tap and lateral roots should be done while putting the seedlings from the polybag into the pit. A planting hole slightly larger than the polybag is first made before the plant is carefully lowered into it. The planting hole is then gently filled with soil and firmly pressed without causing any damage to the soil core from the polybag that is present around the plant.

Leguminous cover crops are grown in the open space between the plants in the first year itself to conserve soil and moisture and enhance the soil nitrogen level. The most popular cover crops are Pueraria phaseoloides and Mucuna bracteata. Calopogonium mucunoides and Centrosema pubescens can also be grown as cover crops. Cover crops are established either from seeds or from stem cuttings. Seeds are sown in well-prepared patches between rows after pretreating with acid or hot water. Seeds of Pueraria (10 mins) and Calopogonium (20 to 30mins) may be soaked in concentrated sulphuric acid before sowing in the field. Centrosema seeds should be acid treated. Mucuna is generally propagated through stem cutting. For hot-water treatment, the seeds may be put in a bucket and water at 60°–80°C is poured over the seeds and kept soaked for 4–5hr before sowing in the field. Sowing should be done just after the pre-monsoon showers and cuttings are planted with the onset of the monsoon under fully wet conditions. About 150kg powdered rockphosphate/ha may be applied in 2 doses 1 and 2 months after sowing. In areas deficient in potash, 50kg of muriate of potash also may be added the same way. The cover crop should not be allowed to grow closer than 2m or on the contour terraces to avoid competition with the rubber plants.

Training and pruning

After planting, care should be taken to ensure that no sprout develops from the rootstock portion and that only one strong shoot of the scion is allowed to grow. No side shoots are allowed to grow up to 2.5m from the ground level. During the immature phase and early years of tapping, highly selective and judicious thinning may be done to eliminate extremely poor trees.

Manuring and fertilization

While preparing the nursery beds, 25kg of compost and 3.5kg of rock phosphate are incorporated in soil for every 10m 2 area of the bed. Six to eight weeks after planting 25kg of NPKMg mixture (10:10:4:1.5) is applied to the soil for every 100m 2 area. A topdressing with urea @ 5.5kg/100m 2 bed area is given 6–18 weeks after the first application of the mixture. When the pits are filled with 12kg of compost or cattle manure or 175g rock phosphate are incorporated into the soil. During the first 4 years an NPK mixture (12:12:16) is recommended for Mg rich soil. Application of 10:10:4:1.5 NPKMg is recommended for Mg deficient soil.

If polybag plants are planted, the first application can be 450g instead of 225g. In first 2 years, 50% of the phosphate should be in the soluble form. In third and fourth year mixture should contain only water-insoluble phosphate. In areas where mulching is done during early years and good cover crops are established, discriminatory fertilizer application based on soil and leaf analysis is recommended from fifth year onwards. If this is not practicable, application of NPK (12:12:12) @ 25kg/ha in 2 equal split doses during April–May and September–October may be given until the trees reach tapping stage. In areas, where no mulching is done and no cover crop is grown application of NPK (15:10:16) is recommended @ 400kg/ha in 2 equal split doses. Application of NPK (10:10:10) @ 900g/tree is recommended in 2 equal split doses during April–May and September–October in case of tapping trees. In areas where rubber trees show Mg deficiency (interveinal yellowing of leaves during September–October) application of 50kg commercial MgSo 4 /ha is given in addition to normal NPK.

From fifth year up to tapping stage, a total 350kg NPK (10:10:10) is recommended/ha in 2 equal split applications (April–May and September–October) every year if cover crop growth is good. Otherwise apply recommended dose of 500kg NPK (15:10:6/ha/year) in 2 equal split doses. For mature tapping trees 340kg of NPK (10:10:10)ha/year is recommended in 2 equal split doses.

The first application should be done immediately after first few pre-monsoon showers before the onset of the regular monsoon. The second application should be done during the dry spell of 4–5 weeks between the south-west and north-east monsoons.

In young nurseries, fertilizer is spread as a linear band between rows and gently forked into the soil without getting in contact with the stem. In field, first application is given in a circular band around the base of the young plant about 7cm away from the base. Similarly, second application is done in a circular band 15cm away from the base of the plant. Until the canopy closes, circular application gradually increases the radius and width. From 5–6 years onwards, fertilizers may be forked into soil in small patches in between the rows with each patch serving 4 trees. If there is good cover crop broadcasting is also sufficient.

Nutrient deficiencies

Deficiency symptoms of Mg and K and in isolated cases Zn and Mn are observed. Mg deficiency is the most common. Interveinal chlorosis is its main symptom. Marginal and tip chlorosis followed by marginal necrosis in older leaves is the typical symptom of K deficiency. Leaf size is also reduced considerably. Zn deficiency also causes intraveinal chlorosis and produces longer leaves. Young leaflets become curved giving a claw like appearance. Mn deficiency is characterized by overall paling and yellowing with green bands along the midrib and veins. In tapping trees pre-coagulation of latex on tapping panel is caused by excessive supply of Mg.

Weed control

Until the cover crop is established regular weeding is necessary. About 4–5 rounds of hand-weeding are required during first 2 years. Once the cover crop is established or after the canopy has closed there is a little weed growth. Standard herbicides could also be used following the routine safety and ecological consideration and particularly if the weed growth is too excessive and manual weeding is not feasible.

Irrigation

Rubber is mainly grown as a rainfed crop. However, with minimum life-saving irrigation in early years, this crop is successfully cultivated even in highly drought-prone areas such as the north Konkan. Polyclonal seedlings are better han budgrafts for such regions as the former have better stress tolerance. Hevea is a hardy perennial tree species that can be grown for the reclamation of marginal and degraded ecosystems.

   
Harvesting & Postharvest management

Latex produced in the bark tissue is harvested through a process called tapping. Tapping is a controlled wounding process during which thin shavings of bark are removed. During tapping latex containing laticiferous vessels which are concentrated in the soft bark and arranged in a series of concentric rings of interconnecting vessel is cut open.

Tapping is initiated when about 70% of the trees in a plantation attain tappable girth. A budded tree is regarded as tappable when it attains a girth of 50cm at a height of 125cm from the bud union. It usually takes 7 years for a rubber plant to attain tappable girth.

The tapping cut, also called the tapping panel, should be at a slope of 30° in budded plants and 25° in seedling trees. Slope should be marked annually using a template. The best yield is obtained by tapping at a depth of less than 1mm close to the cambium so that the cambium is not injured. Shallow tapping results in poor yield. Thus tapping is a highly skilled operation. The tapping panel is usually made as a spiral around the trunk covering half of the girth. Tapping is generally done once in 3 days. Tapping is done early in the morning using a special knife. On an average, a tapper can tap about 300–400 trees/day.

In the past, daily or once in 2 days tapping were practised. Currently once in 3 days or even still lower frequencies are recommended, provided ethephon is used as a yield stimulant. The bark in the tapped portion regenerates by the cambial activity. Bark renewal depends upon the agronomic management, climatic condition, planting density and tapping system.

For the first 6 years tapping is done on one side (panel A) of the tree from the top to down. In the next 6 years the tree is tapped downwards on the reverse side (panel B). During third year the renewed bark on the first side can be tapped again (panel C). However, it is better to adopt controlled upward tapping (CUT) of the virgin bark above the first panel instead of tapping the renewed C panel. A modified knife with a long handle is used for CUT. Here, frequency of tapping can also be once in 3 days or even shorter with yield stimulation. Half spiral or even shorter cuts are practised more recently. The prime considerations while deciding the tapping system, namely frequency, length of tapping cut and stimulant application are optimum crop yield with minimum tapping labour and minimum bark consumption. This prolongs the life-span of the plantation which is generally 20–25 years of tapping.

Judicious application of dilute (1–5% active ingredient) ethephon (2-chloro ethylphosphonic acid) on the panel or on the bark at prescribed intervals and seasons enchances the yield. During rainy seasons tapping can be done by fixing suitable polythene shades as rainguard over the tapping panel. During extreme climate such as drought and severe winter tapping rest is commended for a couple of weeks to avoid stress to the trees. The national average yield is 1.6tonnes/ha/year. The average yield of a well-managed plantation of RRII 105 is 2.4tonnes/ha/year which can be still higher in better plantations.

Latex contains on an average 32% dry rubber content. After tapping, latex drips for 1–2 hr are collected in small cups. Once the dripping is over, the latex is collected from the cups and processed into either crepe rubber, sheet rubber, preserved latex, latex concentrate or block rubber.

The most common and widely followed processing is sheet rubber making. For this, latex is coagulated in suitable containers after proper dilution with water and by mixing with dilute acetic or formic acid (coagulants). The coagulum is pressed in rollers to make sheets which are dried in sun for a few hours. The sheets are then dried in a smoke house (40°–60°C). Various types of smoke houses (permanent/mobile) are available. About 4–5 days are enough to dry these sheets in a smoke house. Dried sheets are graded into different categories. The sheets after grading are packed in vales of 50kg weight and marketed.

   
Physiological Disorders
Tapping panel dryness (TPD) is the only major physiological disorder affecting the rubber tree. This syndrome is characterized by partial or complete drying up of the panel (i.e. no production of latex) after a period of prolonged and late dripping of latex for a few days/weeks. Some trees become dry even without late dripping. In some dry trees, tumors and necrotic bark tissues develop along the bark. The affected soft bark becomes light brown in colour and hence TPD is also known as brown bast. The outer bark get dried and cracks open. Tumors can be seen on the panel area. Otherwise, the tree continues to grow normally. The exact cause of this syndrome is unknown although excessive harvesting of latex seems to be a possible trigger and high-yielding clones are more vulnerable. Giving tapping rest is the only recommendation at the moment, but this is not a fool-proof solution. Low frequency tapping is also recommended which will reduce the incidence of TPD
 
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