Oil palm ( Elaeis guineensis )

Chromosome Number: 32

Taxonomic Classification

Oil palm ( Elaeis guineensis ) is the highest oil-yielding plant among perennial oil-yielding crops, producing palm oil and palm-kernel oil. These are used for culinary as well as industrial purposes. On an average, oil palm produces 4–6 tonnes oil/ha. It can also contribute substantially to the nutritional and energy requirements of the masses. Oil palm is a crop for future and a source for diversification, import substitution, value-addition, health and nutrition, waste-utilization, co-generation (non-conventional energy), eco-friendly and sustainability.

A total area of 0.796 million/ha has been identified in 11 states in India. About 80% of the area is located in Andhra Pradesh and Karnataka. Assam, Gujarat, Goa, Kerala, Maharashtra, Orissa, Tamil Nadu, Tripura and West Bengal are other potential states. Oil palm is being cultivated in 39,413 ha in India under irrigated conditions. Another 5,000ha under rainfed conditions in Kerala and Little Andamans are under oil palm.

Climate and soil

Oil palm is a humid tropical palm which thrives well where annual temperature range is 29°–33°C (maximum) and 22°–24°C (minimum) with an evenly distributed rainfall of 2,500–4,000mm, relative humidity more than 80%, and not less than 5hr sunshine/day. It can be grown up to 900m above mean sea-level.

It can be grown on a variety of soils. But moist, deep, loamy and alluvial soils rich in organic matter with good water permeability are best-suited, for its cultivation. Highly alkaline, saline, waterlogged and coastal sandy soils should be avoided. At least 1m depth of soil is necessary. The soil pH should be 5.5–8.0.

Varieties

There are 3 main types oil palm. They are dura, pisifera and tenera.

Dura

With a thick shell (2–8mm) its fruits have low to medium mesocarp content (35–55%). This is not grown commercially.

Tenera

A hybrid obtained by crossing dura (female) and pisifera (male), it has a thin shell (0.5–4.0mm) with medium to high mesocarp content (60–95%). There is prominent fibre ring in its mesocarp. This is widely cultivated all over the world.

Pisifera

It is a shell-less, fruit-bearing variety.

Propagation

Oil palm is propagated mainly through seeds. Seeds are extracted from fruits using depericarper. Since seeds have dormancy, pre-heating of seeds is done in a heating room for 80 days at 40°C. Then the seeds are soaked for 5 days in running water and kept in cool place. The germination commences in 10–12 days. These sprouts are put in polybags. About 0.4 million tenera hybrid seeds are produced annualy in Kerala. Due to a limited availability, its seeds or seed sprouts are imported from ASD, Costa Rica; IRHO, France; DAMI, Papua New Guinea; UNIPALM, Zaire; and IDEFOR, Cote D'Ivorie.

Of the different systems of nursery raising, the single stage polybag system is most popular. In this system, the polybags (preferably black) of 40cm × 35cm size are used. The bags are filled with a mixture of top soil, sand and well-decomposed cattle manure in equal proportions. A healthy germinated sprout with well-differentiated plumule and radicle should be placed 2.5cm deep at the centre of the bag. Watering should be done daily. Irrigation twice a day and good mulching during summer are desirable. A fertilizer mixture of NP (18:46) is applied @ 3, 5, 8 and 12g/plant during second, third, fourth and fifth months respectively. Afterwards NPK (15:15:15) @ 16, 20, 25, 30, 35 and 40g/plant is applied during sixth, seventh, eighth, ninth, tenth and eleventh months; 5–15g MgSO4 and 0.5–1.5 borax are also applied according to the need after 6 months.

In single stage nursery, the bigger polybags kept closer in the initial stage are to be kept 90cm × 90cm × 90cm apart after 3 months. If double stage nursery is adopted, the young seedlings are to be transferred to bigger polybags after 3 months. Partial shading also needs to be provided at the primary nursery stage with coconut leaves or poly-nets with 75% light interception.

Cultivation

Planting

Planting can be done in any season, preferably during monsoon period. About 10–14 months old seedlings 1–1.3m height from base and 13 functional leaves with good girth at collar are used for planting. The seedlings are planted in the main field in triangular system at a spacing of 9m, accommodating 143 palms/ha. Pits of 60cm × 60cm × 60cm size are dug and 250g DAP or 250g rock phosphate and 50g phorate are applied and mixed with the soil at the base of the pit. Place the seedling in the pit along with the soil after removing the polybag. Fill up the pit with soil and press all around firmly. Copious irrigation should be given immediately after planting. If there is a strong wind, staking may be given and loosely tied to the stake at the base.

Manuring and fertilization

Oil palm is a gross feeder, demanding a balanced and adequate supply of macro, secondary and micronutrients.

The fertilizer must be broadcast around the clean weeded basin, about 50cm away from the palm base and incorporated into soil by forking. Irrigation should be given immediately after fertilizer application. If drip irrigation is adopted fertilizer is to be applied around drip point. The N and K fertilizers can be applied as liquid fertilizer through drip system.

In gardens, where 20–25 tonnes FFB/ha is obtained by sixth year, an additional 20% of the recommended dose can be applied to maintain the productivity . Borax @ 100g/palm/year is recommended if its deficiency symptoms are noticed. Fertilizers can be applied in 2 equal split doses during July–August and December– January. For newly-planted crop, first dose of fertilizer may be given 3 months after planting. Along with the second dose of fertilizer 50–100kg farmyard manure or 100kg green manure and 5kg neem cake/palm can be applied.

Inter/mixed cropping

Oil palm is a wide spaced parennial crop with a long juvenile period of 3 years. Hence, there is a good scope for utilizing horizontal and vertical space for growing intercrops. Crops selected for intercropping should be compatible with the main crop and should not compete with oil palm for light, water and nutrients. Vegetables, pulses, banana, flowers, tobacco, chilli, turmeric, ginger and pineapple are suitable. While raising intercrops, avoid tying of oil palm fronds which reduce photosynthetic activity and ploughing close to the palm base which can cut the absorbing roots and thereby reduce intake of water and nutrients. Allow oil palm to grow freely. While growing greengram, blackgram, cowpea, gingelly and groundnut which do not require frequent irrigation, care should be taken to irrigate oil palm regularly.

If maize, sorghum and sugarcane are to be grown, proper spacing should be given. Oil palm crop should not be affected due to shade and root competition with intercrops. In case of sugarcane, propping and trashing at least to those canes around oil palm basins should be done to avoid shading to oil palm.

Aftercare

Basin management: During first year of planting, basins of 1m radius are to be made around the palm removing the soil from inside so that the soil does not accumulate at the collar region. Basins must be widened to 2m radius during second year and 3m radius from third year onwards. This basin space should be for oil palm only. Sunhemp seeds can be sown in the basin during summer months which grow fast and give a better environment to oil palm, reduce weed growth and evaporation, prevent wind speed and add N to the basin.

Weeding: Basin area of oil palm represents its active root growth zone which can be kept weed-free by hand-weeding or by spraying Glyphosate. Herbicide mixtures of Paraquat with Atrazine, Monouron and Diuron sprayed on ground, twice a year can control weeds effectively.

Mulching: Mulching can be done with dried leaves, empty bunches and male flowers. It conserves moisture, adds organic matter and nutrients, maintains soil temperature, improves physical and biological properties of soil. Coconut husk, sugarcane trash and plastics also can be used as mulching material.

Pruning of leaves: Maximum number of green leaves should be retained on the palm. As a regular practice, all dead and diseased leaves should be pruned. Severe pruning adversely affects both growth and yield of palm. Pruning should be done by giving clear cut to the petiole as close to the stem as possible with the help of a sharp chisel.

Ablation: Ablation is the removal of male and female flowers produced in early stages of plantation. This enables the plant to gain adequate stem girth, vigour and develop adequate root system. Flowering starts 14–18 months after planting. Ablation can be started immediately after the appearance of inflorescences on palms and extended up to two-and-a-half to 3 years depending upon plant growth and vigour. After this stage, pollinating weevil Elaeidobius kamerunicus has to be introduced for better pollination since oil palm is a cross-pollinated crop.

Cover cropping: Most common cover crops which can establish well in oil palm plantations are Pueraria phaseoloides. Calopogonium mucunoides, Centrosema pubescens, Mimosa invisa and Mucuna sp. These can be sown after taking intercrops for first two-and-a-half years in the entire field leaving the basins. They can be ploughed after they are over-grown. Cover crops help in soil and water conservation and check weed growth. When incorporated they also improve organic-matter content of soil and plant nutrient status.

Irrigation

Oil palm requires sufficient irrigation, as it is a fast-growing crop with high productivity and biomass production. Insufficient irrigation reduces the rate of leaf production, affects the sex ratio and results in inflorescence abortion and yield reduction. For grown-up yielding palms of 3 years age and above, a minimum of 150 litres water/day is a must. However, in older plantations during hot summer, this amount may be increased up to 200 litres. When water is not a constraint, basin irrigation can be taken up. Required quantity of water can be given at weekly intervals or once in 5 days depending on soil condition. Irrigation channels must be prepared in such a way that the individual palms are connected separately by sub-channels. For light soils, frequent irrigation with less water should be given. In heavy soils irrigation interval can be longer. If irrigation water is limited and land is of undulated terrain, drip or microsprinkler irrigation can be advantageous. When drip irrigation is given, care should be taken to avoid clogging and for uniform discharg of water. Four drippers are sufficient to discharge 150–200 litres water within 5–6hr.

Harvesting & Postharvest management

Oil palm starts bearing bunches two-and-a-half to 3 years after planting. Proper and timely harvesting of fruit bunches is an important operation which determines the quality and quantity of oil to a great extent. When the bunch is mature and ready for harvesting, fruits in bunch turn yellowish-orange, and 5–10 fruits from each bunch drop on their own. When pressed hard with fingers, orange coloured oil exudes from the fruits. While harvesting, a stalk length of 5cm alone should be left. Harvesting should be done at 10–12 days intervals during rainy season. It should be done at closer intervals of 6–7 days as ripening is hastened after rains.

For young crop, a sharp chisel attached to an aluminium/iron rod is enough. For adult palms of 8' height and above, harvesting knife fitted to an aluminium rod extendable up to 45' can be used.

Palm oil extraction: The yield of oil palm depends on variety, age and management practices. From fifth year onwards, the average yield may be 20–25 tonnes FFB/ha/year. It can also yield up to 30–40 tonnes FFB/ha/year. The average weight of a harvested FFB is 20–25kg and average number of bunches would be 10–12/ palm/year. Bunch weight up to 60–100kg is also possible.

Palm oil is extracted from the mesocarp of fruits which is highly perishable in nature. To obtain good quality raw palm oil, the fruits are processed within 24hr after harvesting. The processing consists of many steps. These are:

Sterilization is done by heating with steam pressure of 3kg/cm2 for 40–60 min. It is done to inactivate the enzyme lipase which would raise the free fatty acid content of oil, to loosen the fruits to facilitate subsequent stripping, to soften the tissue for better digestion and to coagulate the protein and to dehydrate the kernel partially. After sterilization, the bunches must be stripped. This process involves the separation of fruits from bunches by passing through a rotated rotary drum stripper. Digestion is done to disrupt the mesocarp and to break up the maximum number of oil-bearing cells to facilitate oil release. This process also frees the nuts from the fibre. Digester is a vertical steam jacketed cylinder provided with beater arms and situated directly over the screw press. The hot digested mash is fed to the press continuously and pressure is developed due to compression. The oil water mixture is expelled through the perforations while the press cake is discharged through the other end of the screw.

The crude oil from the screw press contains a mixture of oil, water, cell debris and particles of fibre and shell. It is first passed through a double vibrating screen to remove particles. Hot water is then added and the oil is allowed to separate in clarification tanks from which it is continuously decanted. The oil from clarification tank still contains 0.4–0.6% water, 0.1–0.2% sludge and other impurities. This affects the quality of oil. Bulk of water and other impurities are removed by a high speed centrifuge with 8,000 rpm which can bring down the moisture level. Further reduction of moisture to the optimum level of 0.1–0.15 is achieved by vacuum drying. Finally the vacuum dried oil is pumped to storage tanks. This oil is called as crude palm oil rich in vitamin A and E.

The pressed cake is passed along a steam jacketed screw conveyor, the nuts are separated by blowing off the lighter fibre in an air stream within a vertical cylinder. The nuts are cleaned and polished and the fibre is conveyed to the boiler stations.

Kernel oil extraction: Palm kernel oil is derived from the palm nut recovered from the press cake. The cleaned, polished nuts fed to the cracking section usually consist of revolving screens to grade nuts, crackers, and screens or columns to separate uncracked nuts and/or dust and small shell particles from the mixture. Palm kernel and shell mixture is separated into kernel and shell in a clay bath maintained at a particular specific gravity. The shells being heavier, sink and the kernel being lighter floats and is skimmed off. The separated kernels are dried to a final moisture of 6–8%. The kernel is powdered and steam conditioned followed by extraction of oil in expeller. The palm kernel oil is similar to coconut oil in fatty acid composition and it fetches a premium price. Oil extracted from the fleshy orange red mesocarp is known as crude palm oil which on refining becomes palm oil commercially known as ‘Palmolein'. It has thick consistency, red colour and high smoke point. Hence, it is further purified.

Okra ( Abelmoschus esculentus )

Chromosome Number: 56-199

Taxonomic Classification

Okra is an annual vegetable crop grown in tropical and subtropical regions. Specific varieties are grown even in lower hills with moderate climate. Tender, green fruits are cooked in curry and soup. The root and stem are used for clearing cane juice in preparation of ‘gur’. High iodine content of fruits helps control goitre while leaves are used in inflammation and dysentery. The fruits also help in cases of renal colic, leucorrhoea and general weakness. In India, the crop has not adapted as leafy vegetable as in Far East countries. It has yet multiple uses. The dry seed contains 13–22% good edible oil and 20–24% protein. The oil is used in soap, cosmetic industry and as vanaspati while protein is used for fortified feed preparations. The crushed seed is fed to cattle for more milk production and the fibre is utilized in jute, textile and paper industry. Uttar Pradesh, Bihar and Orissa are major okra-growing states in India.

Climate and soil

Okra requires a long, warm and humid growing period. It can be successfully grown in hot humid areas. It is sensitive to frost and extremely low temperatures.For normal growth and development a temperature between 24°C and 28°C is preferred. At 24°C the first flower bud may appear in the third leaf axil while at 28°C it may appear in sixth leaf axil. This higher position is not necessarily accompanied with a delay in time because at higher temperatures the plants grow faster and the higher position is reached earlier. For faster plant growth still higher temperature helps though it delays the fruiting. But at higher temperatures beyond 40°–42°C, flowers may desiccate and drop, causing yield losses. For seed germination optimum soil moisture and a temperature between 25°C and 35°C is needed with fastest germination observed at 35°C. Beyond this range the germination will be delayed and weak seeds may not even germinate. Adjustment of climatic factors helps in taking at least one (summer) crop in hills, 2 or even 3 (summer, kharif and late kharif) crops in the east, west and north Indian plains and almost year-round cultivation under moderate climate in south India. It is grown on sandy to clay soils but due to its well-developed tap root system, relatively light, well-drained, rich soils are ideal. As such, loose, friable, well manured loam soils are desirable. A pH of 6.0–6.8 is ideally-suited. However, okra Pusa Sawani has some tolerance to salts and thus also to larger pH range. All soils need to be pulverized, moistened and enriched with organic matter before sowing.

Varieties

Important commercially cultivated varieties in different parts of the country are: Arka Abhay Resistant to yellow-vein mosaic virus, its plants and fruits resemble to those of Arka Anamika in appearance. It is tolerant to fruit-borer and may suit pruning to tame the plant for a ratoon crop. It is a sister line of Arka Anamika. Arka Anamika Its plants are 100cm, upright, open and slightly pigmented on stems, petioles and lower leaves. Fruits are dark green with 5 prominent ridges and comparatively less smooth surface. It takes 50 days (6th node) to first flowering and 55 days to first picking of tender marketable fruits. It is excellent yielder in south but with a lower performance in northern India. It is resistant to yellow-vein mosaic, the yield being 125q/ha. Azad Kranti The plants of Azad Kranti are fast-growing, occasionally branched and with sparse pigmentation. The fruits are green, smooth, shiny, long, 5-ridged with long beak, the leaves are green, normally lobed. It is tolerant to yellow-vein mosaic virus, the yield potential being 125q/ha. It is suitable for cultivation in spring-summer season. Co 1 Its plants are tall with 6–8 branches. Stems, shoots, petioles midribs and basal veins of the lower surface of leaf lamina are prominently scarlet red. Leaves are light green, medium-sized and deeply lobed. Petioles are longer (around 24cm). The fruiting starts from 5th node. The fruits are glossy, slender, 5-ridged, scarlet red (colour non-persistent on cooking), borne on an average 20 fruits/plant. It has field tolerance to yellow-vein mosaic virus but is susceptible to fruit-borer and powdery mildew. MDU 1 The plants are tall growing with short internodes (6cm) bearing 10 fruits each. Stem is green with light purple pigmentation. Bearing starts in 33–35 days after sowing from 4–5 node. The first picking starts 43 days after sowing. Fruits are light green, about 20cm long having 52 seeds/fruit. The fruits are well-filled, weighing around 29g each. Gujarat Bhindi 1 Its plants grow 60cm high in spring-summer and 90cm in kharif season. The plants are erect with purple tinge on stem. Leaves are broad, dark green, with purple tinge on veins. It takes 55–60 days to first picking. Fruiting starts from 4–5 node. The fruits are 5-ridged, tender, 14–15cm long and 6–7cm in girth. It yields around 70q/ha green fruits. Harbhajan Bhindi Its plants are very tall, thick and prolific-bearing with large, moderately lobed leaves having rough surface and prominent veins. The fruits are very long, tapered, bright green, spineless and mostly 8-ridged. Hisar Unnat It is resistant to yellow-vein mosaic virus. Its first picking may be taken in 46–47 days. It is high-yielding (120–130q/ha green fruits) variety. Plants are medium-tall with short internodes, producing 3–4 branches each. Foliage is green, petioles occasionally pigmented. Petal base is pigmented from inner side only. Fruits are green, attractive, 5-ridged, measuring 15–16cm in length on full maturity. It is suitable for growing during summer as well as rainy season. Parbhani Kranti It has tall, single-stemmed plants with dark green foliage. The leaves are deeply lobed appearing like cut leaves towards plant apex. First flush becomes ready 55 days after sowing. The fruits are smooth, dark green, tender, slender, 5-ridged with long beak. Average green fruit yield varies from 85–90q/ha during spring-summer to 115q/ha in rainy season. Seed yield varies from 5–6q/ha in spring-summer to 10q/ha in rainy season. Perkins Long Green Its plants are green, upright, producing green fruits of excellent quality and appearance. The variety is suited for cultivation in slightly cooler climates in lower northern hills. With the development of present day high-yielding varieties, its cultivation is now limited and localized. Punjab 7 The plants are tall in kharif and medium-tall in spring-summer. Stem carries splashes of pigmentation. Leaves are dark green with less lobing and less serrated margins. Petiole base is deeply pigmented. Plant is sparsely hairy. Fruits are medium-long, green, 5-ridged, slightly furrowed with less pointed beak. Fruits are borne on 5th–6th node, 50 days after sowing. It yields 100q/ha in kharif and 50q/ha in spring-summer. Punjab 8 Its plants are tall with purple pigmentation splashes on stems, petioles and lower surface of the leaf base. Stem, petiole, leaves and fruits are sparsely hairy. Fruits are medium-long, thin, tender, green and 5-ridged. It has field resistance to yellow-vein mosaic virus and tolerance to shoot and fruit-borer. It may be cultivated in kharif as well as in spring-summer season in north India. Punjab Padmini The plants of Punjab Padmini grow fast, up to 180–200cm, single stem at 45 × 30cm but medium branched at higher spacing. Pigmentation is visible on stem, shoots, petiole and lower basal veins of leaves. Leaves are dark green, medium-lobed and plant is hairy. First picking is available in 53–54 days. Fruits are dark green, fast growing, smooth, 15–20cm long and 5-ridged, weighing 20–21g each. It possesses field resistance to yellow-vein mosaic virus and tolerance to jassids and cotton boll-worm. It is suitable for kharif and summer seasons of north and winter season of southern India. On an average, the yield is 100–125q/ha green fruits or 12.5q/ha dry seed. Pusa A 4 The plants are dark green with sparse pigmentation (occasional) on stems and petioles with usually single stem having short internodes (2–4cm). The leaves are broad, medium-lobed. The fruits are 5-ridged, attractive, dark green, 12–15cm long having excellent shelf-life. It is resistant to yellow-vein mosaic virus and tolerant to aphids and jassids and least preferred by shoot and fruit-borer. In summer season, it yields 100–120q/ha, while kharif and late kharif crop yield up to 175q/ha. Pusa Makhmali This is a 5-ridged cultivar with excellent quality fruit. Fruits are light green, tapered, attractive and 12–15cm long, the yield potential being 80–100q/ha. It is suited for cultivation in hills and virus-free regions (spring-summer in north India and rainy season in southern India). The plants are hairy, tall, erect, less branched with palmate and hairy leaves. Pusa Sawani It needs 45–50 days from sowing to first picking. First fruit is borne on 6–8 node. Upper leaves are deeply lobed. It is suitable for cultivation in both spring-summer as well as kharif seasons as it is day-neutral and less sensitive to temperature fluctuations. It has a very wide adaptability. In hills, it can be sown from April to May depending upon the altitude, while in plains, virus-free period is better suited (spring-summer in north). Its yield is 120–125q/ha Red Bhindi Released for southern plains, its fruits are 5-ridged, red, long and slender, fleshy with lesser seeds than Pusa Sawani. It gives good yield under southern plains though its cultivation is limited. The red colour of fruits disappear on cooking. TN Hybrid 8 The plants are branched type having sparse pigmentation except on fruits, green foliage and green, 5-ridged, medium-long fruits. It has fair degree of adaptation and is also a high yielder even under north Indian conditions. It is resistant to yellow-vein mosaic virus. Varsha Uphar It has high degree of resistance to yellow-vein mosaic virus and field tolerance to leaf hoppers. It is recommended for cultivation in disease-prone areas. However, it can be grown in spring-summer as well. Its plants are medium-tall with short internodes, producing 2–3 branches each. Foliage is dark green, lower leaves broad with shallow lobes. It takes 46–47 days to first picking. Fruit bearing starts from the 4th node. Fruits are smooth, dark green, attractive with long tapering tips measuring 18–20cm on full maturity. Average number of seeds/fruit is 55–60. Due to fast growth of fruits, harvesting on alternative days is recommended. It is a prolific-bearer with an average fruit yield of 100q/ha. Besides, a number of hybrids from many private sector agencies/seed companies are marketed. Of these, Varsha, Vijay, Adhunik, Panchali, Hybrid No. 6, 7 and 8, Nath Sobha, Supriya, Sungro 35, Aroh 1, –2, –3, –9 and are popular.

Cultivation

Sowing Okra gives little success on transplanting and thus seed is sown directly in the soil by seed drill, hand dibbling or behind the plough. Broadcasting is not recommended as it increases seed rate as well as causes great inconvenience in cultural operations and harvesting. Sowing on ridges ensures proper germination, reduces water requirement during spring-summer and helps in drainage during rainy season. A planting distance of 60cm × 30cm, accommodating 55,000 plants/ha is recommended for branching and robust types, while 45cm × 30cm accommodating 75,000 plants/ha is for non-branching types. During spring-summer season with less plant growth these spacings are kept at 45cm × 30cm or even less. For harvesting smaller fruits for fresh fruit export a group of 2–3 rows at 20cm distance keeping 60cm between these groups of rows could be planted allowing 20–30cm between plants within the rows. This eases harvesting and checks branching. The seed rate of 18–22kg/ha for spring-summer and 8–10kg for rainy (kharif) season crop is optimum. Higher seed rate could be used if the crop is to start early in spring summer as it augments germination loss due to low temperature. Higher seed rate and lower spacing could also be opted for summer crop to lower the field temperature and keep fruiting going on under frequent light irrigation. Soaking seeds in 0.2%. Bavistin solution overnight helps activate germination and protects seedlings from wilt. Soil treatment with Furadon @ 2kg ai/ha (20–22kg product) helps protect plants from root-knot nematodes and other pests during initial 4–5 weeks. The soil should be well-prepared and whole of organic matter, P, K and half of N should be thoroughly mixed. Sufficient soil moisture and temperature around 30°C help in quick and uniform germination. Sowing in moist soil is preferred over irrigation after sowing. June-end is sowing time for kharif crop and February-end to early-March for spring-summer crop in north India. In southern India, it could be grown year round. Winter crop with November-sowing is also taken. In north Indian hills, it is sown during April–June while in eastern and western India, summer crop sowing is done during January–February. In West Bengal, sowing continues from February to June. Training and pruning Okra as such does not require training or pruning. Varieties developed so far are upright growing and hence staking is also not practised. Recently, some success has been achieved in raising near normal kharif crop (ratoon) from plants of spring-summer sowing by pruning the plants after summer fruiting and with the onset of the rains, from 20–25cm above the ground, adding organic and inorganic matter in the soil and providing plant-protection cover. Okra Arka Abhay and Pusa A 4 give quick branching after pruning. Manuring and fertilization The farmyard manure should be mixed in soil at the time of land preparation along with whole quantity of P and K. Half of N should be added to the soil before sowing, while one-fourth before flowering as side-dressing and one-fourth in 3 consecutive foliar sprays (1% urea) at 10 days interval during fruiting. Okra responds to 150kg N/ha depending on genotype and soil fertility. Similarly soils deficient in P and K improve fruiting and fruit quality when these are applied to the soil externally. Moreover fruiting and fruit appearance are also improved. With the advent of high-yielding varieties and hybrids, their nutritional requirement has gone higher. Aftercare Thin out the closely germinated plants at one true leaf stage. Proper weed management in okra could save up to 90% crop losses due to weeds. A total of 3–4 weedings starting from 20 days after sowing are required till the crop covers the soil surface. Use of weedicides reduces the number of weedings to zero during summer and 1 during kharif (rainy) season. Fluchloralin (Basalin 48ec) @ 1.2kg/ha as Pendimethalin (Stomp 30ec) @ 0.75kg/ha as post sowing and pre-emergence soil surface spray gives initial control of dicot weeds, though one weeding may be needed in kharif crop. Okra could be taken in different cropping systems. In sequential cropping, potato–carrot–okra; okra–potato–tomato; cauliflower–tomato–okra; groundnut– greens–wheat–okra; okra–palak–potato–muskmelon and okra–radish–cauliflower– squash–cowpea give crop security and higher income/unit area. Okra + radish and okra + Frenchbean give higher returns than solo crop. They respond to higher doses of NPK indicating better utilization of fertilizers under intercropping. Okra could give 300–500% crop land-use efficiency as an intercrop in cassava and cucurbits. Growing okra–cowpea–maize, maize–okra–radish and okra–okra–radish reduces bacterial wilt in tomato and brinjal taken as succeeding crop. Irrigation First irrigation should be given when first true leaf initiates in spring-summer and when it expands in kharif (rainy) season. Subsequent irrigations at 4–5 days interval are given to summer crop. If temperature goes around 40°C, frequent light irrigations are recommended to help proper fruiting. Thus soil should be kept moist and flooding or wilting of plants should be avoided. Drip irrigation saves around 85% water requirement though it is not yet commercial in okra. Furrow system is better than flood system. Mositure stress during flowering and fruit/seed setting causes around 70% crop losses. The nutrient uptake from soil is also at peak during fruit set and development stages. A water stress in the field during this period not only causes yield reductions but also affects the nutritional status of the fruits.

Harvesting & Postharvest management

Early harvesting gives lower yields of tender fruits with shorter shelf-life. In general, harvesting on every alternate day is advisable. A cheap hand glove or cloth bag should be used to protect fingers. Harvesting in the morning is convenient. For distant markets, harvesting late during evening and transporting during night is also advised The fruits are graded. For processing industry and fresh fruit export 6–8cm long fruits are sorted out. Longer fruits are used for fresh market. For local market, fruits are cooled (preferably) and filled in jute bags or baskets, covered or sewed and then water sprinkled over it. This helps in cooling as well as in turgidity of fruits which tightens the pack and saves product from bruises, blemishes and blackening. In air-tight containers the fruits may turn pale during transit due to heat generated by them. For export, suitable size perforated paper cartons are taken and precooled fruits are packed and transported in refrigerated vans. Export market requires tender, dark green, straight, short (6–8cm) fruits. 

Nutritional Value

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Olive ( Olea europaea )

Chromosome Number: 46

Taxonomic Classification

Olive is found growing wild in the Himalayan region comprising Kullu, Shimla, Solan and Sirmour districts of Himachal Pradesh. It is extensively used for extraction of oil from its fruits. Its oil is edible, possessing valuable therapeutic character. About 92% of its produce is used for oil extraction. The main producers of olive oil are Spain, Italy, Greece, Turkey, Syria, Algiers, Morocco, Egypt, Tunisia and adjoining gulf countries. In India, olive cultivation has been undertaken on a limited scale in north Sub-Himalayan region comprising Jammu and Kashmir, Himachal Pradesh and Uttar Pradesh.

Climate and soil

Normally olive is grown in warm, temperate to subtropical climate. It can be grown up to 800–1,400m above mean sea-level. Temperature is most important factor influencing its cultivation. Olive cultivars require 7°–35°C, however 15°–20°C is ideal. Occurrence of prolonged hot and dry summers coupled with acute water stress cause post-anthesis flower and fruit drop. Adequate chilling at 7°–20°C during winter is essential to break rest period and to promote fruitfulness. Olive tress are not irrigated but they require 950mm water during their entire growing season. A well-distributed rainfall is conducive for growth of trees. Lack of adequate soil moisture due to prolonged drought during summers causes fruit drop. Inadequate or delay in rain during winter season delays emergence of new flush, causing a substantial reduction in flower-bud differentiation. Occurrence of autumn frost is more harmful, since it affects fruit maturation and oil accumulation.

Occurring of hailstorms at pre-bloom, bloom and post-bloom period causes higher abscission of flowers and young fruits. At blooming stage hailstorms render trees completely devoid of fruits, inducing alternate or irregular bearing in its trees.

Although olive grows well in a wide variety of soils, it requires deep, fertile and well-drained soil for optimum growth and productivity. Loam and silt clay loam soils are well-suited for its cultivation. Poor or calcareous soils are not suited for its cultivation. Soils 4–6 feet deep are well-suited. The soil should be well-drained to permit good aeration and extensive root development. The sub-soil is, therefore, more important than upper layer of soil in ensuring better growth and productivity of its trees. On the contrary, olive trees do not tolerate wet soils for a prolonged period, since it results in eventual death of its roots. Soil pH of 6.5–7.5 is ideal. However a pH exceeding 8.5 adversely affects its growth and productivity. Its trees can tolerate a fairly high amount of Ca and B.

Varieties

Its varieties can be divided into 2 categories. They are: oil type (Carolea, Coratina, Pendolino, Frontoio, Canino, Ascolanaterena and Aglandeau) and pickle type (Ascolano, Mission, Grosseune, Picholine, Cornicobra and Coratina).

Ascolanaterena

Trees very vigorous, upright and compact; inflorescence short, sparse; fruits spheroidal, black with rounded open and slightly asymmetric. Yield moderate to heavy. Resistant to cold and Cycloconium-knot.

Ascolano

Trees vigorous; inflorescence short and sparse; yield moderate to high; fruits spheroidal, large-sized but slightly asymmetric, turn black on ripening. Stones large. Resistant to Cycloconium-knot and cold but susceptible to olive fly. Pulp : stone ratio quite high and oil content 22–24%. It is suitable for pickling.

Canino

Trees moderately vigorous and spreading; self fruitful and regular-bearer, inflorescence short, and paniculate; fruits small-sized, elliptic with pointed apex. Yield moderate. Resistant to drought.

Carolea

Trees upright, moderately vigorous, inflorescence racemose, but short and compact; fruits asymmetric, bright black, spheroidal, and large sized. Yield good, oil content 20–21%. Resistant to cold, drought and frost but susceptible to Cycloconium-knot and olive-fly.

Coratina

Trees moderately vigorous; inflorescence short and compact; fruits large-sized, oval and slightly asymmetric; late ripening; heavy-yielder with 23–25% oil content. Stones medium-sized. Resistant to drought and cold but susceptible to olive knot, olive fly and peacock eye. It is suitable for pickling.

Frontoio

Trees moderately vigorous; inflorescence large and sparse; fruits medium, purple-black and oval-elongated. Ripen late, oil content 23–25%; yield high and consistent. Stones large-sized. Susceptible to cold, Cycloconium-knot and olive fly.

Leccino

Trees vigorous; inflorescence short and sparse; fruits medium-sized and purple-black, spheroidal with rounded apex; stone: pulp ratio medium; yield medium and consistent; oil content 25–30%. Resistant to low temperature but susceptible to sooty-mould and Cycloconium-knot.

Pendolino

Trees moderately vigorous; inflorescence large and compact; fruits medium-sized, oval, and asymmetric with rounded apex, black colour at maturity. High-yielder, oil content 23–24%. Stones medium-sized, spheroidal with smooth surface. Susceptible to Cycloconium-knot and cold.

Propagation

Olive can be propagated by seeds and cuttings. The partially ripe fruits are collected during September–October. The stones are separated from their pulp by dipping them in caustic soda containing 10% NaOH or KOH in a dilute HCl. The stones are thoroughly washed in running water to remove all traces of chemicals. They are immediately sown in raised nursery beds at a spacing of 15cm from row-to-row and 5cm from seed-to-seed. The nursery beds are mulched and regularly irrigated. The seeds germinate with the onset of spring season. However, a few seeds germinate 1–2 years after sowing.

Propagation by cuttings is a simple method. The plants raised by this method are uniform in their growth and productivity. Leafy, sub-terminal cuttings 12–15cm long of pencil thickness having 3–4 nodes each are taken from the mother tree. The cuttings are wounded at their base and kept moist until their pre-treatment with 500ppm NAA+3,000ppm IBA for 10 seconds. This treatment is most effective for olive Frontoio and Coratina. The cuttings are then planted in a mist chamber under controlled environment. The optimum temperature for rooting is 22–25 ± 1°C with 70% relative humidity. The roots emerge 6–8 weeks after planting. The rooted cuttings are taken out from the mist chamber 10–12 weeks after their planting and kept for a short period in hardening chamber. The rooting medium of pure sand or vermiculite can be used. Then these are transplanted on nursery-beds. Planting time varies from cultivar-to-cultivar. Olive Aswiterana roots well in March, whereas those of Frontoio, Coratina, Pendulino and Cornicobra during June-end. The cuttings of Aglandeau give maximum rooting (>80%) in January.

Olive seedlings can be conveniently grafted by veneer or cleft or tongue grafting. March–April is optimum time for grafting. Of different methods, I-budding and patch budding are most effective.

Rootstocks

Seedlings of wild olive can be used as rootstock for propagating commercial cultivars.

Cultivation

Planting

The planting distance depends upon region, soil type, its fertility, cultural practices, availability of irrigation, and vigour of scion and stock. In deep, fertile soils having assured irrigation facilities olive trees should be planted 8m apart. If semi-dwarf rootstocks are used planting should be done 6–7m apart. The planting density should be 150 trees/ha, when planted 8m apart, whereas it should be 250–300 trees/ha with a planting distance of 6–7m. In a rectangular plantation, a planting distance of 8m × 5m or 6m × 5m corresponding to a planting density of 250 and 333 trees/ha, can also be used.

In irrigated areas, January–February is ideal planting time. But areas which are prone to prolonged periods of drought during summers with a negligible or no irrigation facility, July–August is ideal to plant olives. In areas experiencing heavy monsoon rains, planting should be delayed. An efficient drainage system is a prerequisite in waterlogged areas since olive plants are too sensitive to such conditions.

In poor soils, pits of 90cm × 90cm size should be dug, whereas in good, rich and loamy soils, 60cm × 60cm size is adequate. The pits should be dug up at least 2 months before planting. The sub-soil should be well-mixed with farmyard manure and superphosphate. The pits should first be filled with a mixture of soil and fertilizers and then with top soil.

The trees should be planted 2–5cm deeper than they were in the nursery. In sandy or dry soils, it is desirable to plant them still deeper. While planting, care should be taken that graft union is kept about 25cm above the ground level. All broken, injured or rotten roots must be trimmed before planting. The earthball containing plant roots should be soaked in 1% copper sulphate before planting. In feathered plants, stronger scaffold limbs should be trained to keep the plant straight. Ensure a minimum disturbance to root system of the plant while transplanting.

There are several planting systems used for orchard layout but selection of a suitable system of planting depends upon topography of the land, cultivars, rootstock used, soil management system and intended method of harvesting. However, square, rectangular, triangular, contour and hedgerow systems are adopted for planting olive trees.

Training and pruning

At the time of planting, a support system of about 10 feet should be erected. In a feathered tree, develop a clean stem to a height of 45cm from the ground and select one branch each to the left and right which can be tied to lowermost wire. Remove weak laterals. In the second growing season, develop another set of scaffolds on the next higher wire and repeat the process. Eliminate all other undesirable scaffold branches. In third growing season, another pair of lateral scaffold branches are developed to the next higher wire. The secondary scaffold branches are allowed to develop on main scaffold branches but if they become over-vigorous, they should be headed back. All upright growing shoots which either compete with the leader branch or arise from main scaffold limbs are eliminated soon after their emergence. When tree attains a height of 4 m, it is headed back to a weak lateral. The intensity of pruning in later years is kept minimum until tree attains bearing age.

Young non-bearing trees can be pruned any time of the year if weather is clear and free from intermittent rains. However, pruning of trees should be avoided when prolonged drought period coupled with acute water stress prevails. In bearing trees, pruning should always be carried out immediately after harvesting to encourage new growth for initiating floral buds for the next season.

The intensity of pruning depends upon vigour of cultivar, age of tree, availability of irrigation, and bearing behaviour of the tree. During transitional phase, only light pruning is adopted but as the tree becomes older, the intensity of pruning is to be increased accordingly. In old trees, rejuvenating type of pruning is required which involves heading back of main scaffold limbs to encourage new vigorous shoots which begin fruiting after 2 years.

In young plants, only corrective pruning should be done as and when necessary. Pruning during initial 2–3 years is not advisable. However, occasional removal of water sprouts, dead or mechanically injured branches should be carried out regularly. A clean trunk devoid of any feathers should be developed up to a height of 40cm above the ground. The higher intensity of pruning during initial years stimulates strong vegetative growth. The pruning wounds should be immediately disinfected with boardeaux paint. This minimizes the chances of various pathogens entering into the plants and also hastens the process of healing.

Manuring and fertilization

A comprehensive knowledge about the nutritional requirement of olives is essential to provide them a balanced nutrition and to maintain an equilibrium between their growth and productivity. This becomes more important when olive trees are grown on poor soils under rainfed conditions.

The whole quantity of phosphatic and potasic fertilizers should be applied along with farmyard manure and Borax during October–November in irrigated areas, but in rainfed areas at the onset of the winter rains. The N should be applied in 3 split doses. Half dose of N should be applied immediately after harvesting or with the onset of the winter rains in December; one-fourth during February–March 8 weeks before flowering and remaining one-fourth during June–July with the onset of monsoon rains. The farmyard manure along with nitrogenous fertilizer is evenly broadcast in the drip area of the tree. It should be mixed with top soil. But phosphatic and potassic fertilizers along with Borax should be applied in a trench 15cm wide and deep in the drip area of the tree. The trees should be irrigated after fertilizer application.

Aftercare

Young plants should be well maintained by controlling weeds judiciously. They should be regularly irrigated, whenever necessary. Adequate moisture conservation and drainage measures should be undertaken. For 6 months old trees in irrigated areas, apply 10–20g calcium ammonium nitrate at monthly intervals along with irrigation. These plants should also be protected from various insect pests. Nitrogenous fertilizer should not be applied to newly-planted saplings until they are 6–8 months old.

Staking

Tree must be tied to the stake in such a way that it stands firmly without chopping or rubbing against the stake. In the first one or two years, a soft gunny thread (sutli) should be used. Afterwards a strong rope even of nylon can be used. It is advisable to use a piece of gunny bag on the stem of the plant before tying it with a strong rope. The knot should be loose enough to enable the trunk to thicken. These ropes should be readjusted at least once a year.

All undesirable suckers should invariably be removed. However, under exceptional circumstances, only well-placed suckers which do not interfere with the framework of the tree can be retained whereas the remaining ones are eliminated. If a situation of profuse suckering is confronted then stubs of eliminated suckers be treated with 1% NAA in Lanolin paste to suppress the emergence of new suckers.

Mulching

Mulching is very effective to conserve moisture and to lower evaporation losses from soil surface. Hay, white polythene film or tree leaves can be used for mulching. But care should be taken to remove mulch material before the onset of the monsoon. The mulch should be applied during late winter but much ahead of the drought period.

Weed control

All annual, perennial and grasses growing in olive plantations should be controlled effectively. Controlling them manually is most expensive. Therefore spraying of appropriate weedicides is quite effective control measure. Apply Glyphosate @0.18–0.36kg/ha depending on weed intensity. Repeat the spray 2–3 times during entire growing season. Simazine + Diuron (2kg/ha) may be used to control grasses. The application of Gramaxone (2–3 litres/ha) is effective to control perennial weeds.

Irrigation

Mature olive trees require 950mm water during March–September. Although its trees are seldom irrigated, deficit irrigation practices cause a marked reduction in fruit quality and yield. It is, therefore, imperative to maintain optimum levels of soil mixture throughout the growing season which in turn ensures adequate tree growth and economical yield.

The time of irrigation should coincide with the period of water stress in the area. The olive trees have certain critical periods when adequate supply of water is needed to keep equilibrium between growth and productivity of trees. It is necessary to apply one irrigation 4 weeks prior to the expected time of flowering. This ensures adequate development of flower and lowers down flower bud/flower abscission. The trees should be irrigated after 2 weeks of their peak blooming period. This improves the fruit set. One irrigation a month after fruit set stimulates development of young fruits, and reduces their drop/abscission.

There are two well-defined classes of fruit utilization—table olives and mill olives. Mill olives contain more oil, and less sugar and water than table olives.

Harvesting & Postharvest management

Early harvesting of firm but immature olives decreases both quality and quantity. Delay in harvesting produces oil of higher acidity. Oil extracted from over- ripe fruits is susceptible to all type of damages and deteriorates rapidly during postharvest period. Some varieties develop a higher acidity and undesirable sensory characters in oil obtained from over-ripe fruits.

The olives should be harvested when oil with a good quality and pleasant aroma is obtained without much bitterness. In pickle cultivars, relative changes in fruit firmness, colour and degree of bitterness of the oil obtained 25 weeks after flowering show a gradual decline in bitterness and a minimal value of bitterness in oil coincides with a strong change in colour corresponding to purple black colour/stage. This happens 29 and 30 weeks after flowering. It can, therefore, be considered as a point at which the best oil quality can be obtained. Furthermore, the fruits at this stage suffer less damage during postharvest handling.

Hand-picking is the most suitable method of obtaining a high quality oil as it preserves fruit integrity. It is an expensive and a slow method, so it is economically impossible to collect all the fruits at optimum maturity. This leads to indirect losses in oil quality owing to either the increased quantity of immature fruits or an increase in the proportion of over-ripe fruits if harvesting is either advanced or delayed. Therefore, there is a need to use mechanical or chemical methods to reduce harvest costs and to improve the quality of oil.

The greatest deterioration of olives takes place between harvesting and processing. In these conditions, all kinds of degenerative and pathogenic infections develop in the fruit. Aerobic agents also act in the innermost zone of the pile and there is a marked increase in temperature of this zone which accelerates fruit degradation. Aerobic organisms also act in the outermost areas of the heap/pile and oil obtained from these fruits is characterized by a high acidity produced by lipases of both olive and parasitic origin. 

Nutritional Value

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Onion ( Allium cepa )

Chromosome Number: 32

Taxonomic Classification

Onion is one of the most important commercial vegetables. It is grown in western, northern as well as in southern India. Maharashtra, Gujarat, Uttar Pradesh, Orissa, Karnataka, Tamil Nadu, Madhya Pradesh, Andhra Pradesh and Bihar are major onion-growing states in India.

Climate and soil

Onion is a cool season crop. However, it can be grown under a wide range of climatic conditions. It grows well under mild climate without extreme heat or cold or excessive rainfall. In areas where average annual rainfall exceeds 75–100cm in the monsoon periods, it can be grown only as a summer crop. The ideal temperature requirement of the onion crop is 12.8°–21°C before bulbing and 15.5°–25°C for bulb development. Very low temperature in the early stages favours bolting, whereas a sudden rise in temperature favours early maturity in rabi, resulting in small-sized bulbs. Onion can be grown on all types of soils. However, deep friable loam and alluvial soils are best for its successful production. Free drainage, freedom from weeds and presence of organic matter favour production of good crop. It cannot be grown in alkaline or lowlying marshy lands. The optimum pH is 5.8–6.5.

Varieties

A number of varieties have been developed in India. Onion varieties can be broadly classified into 2 groups—common onion and multiplier onion. Common onion can be further grouped into 3 sub-groups based on colour of skin—red, yellow and white.

Cultivation

Planting Common onion can be grown by raising seedlings in a nursery and transplanting them in field, planting bulbs directly in the field, broadcasting or drilling seeds directly in the field and planting sets for production of kharif onions Transplanting It is more commonly practised for an irrigated crop, resulting in a high yield with large-sized bulbs. Seedlings are first raised in the nursery. For an early kharif crop in south India, March–April is optimum time of sowing. August–September is most suitable time for a kharif crop. For a rabi crop in plains, it is October—November. For high altitude hilly areas, March–April is recommended as sowing time. A nursery bed of 3m × 0.6m size may be raised up to 15–25cm with a distance of 70cm between the beds to facilitate intercultural operations. Generally sandy loam soils are preferred for nursery beds. The edge and top of the bed should be quite firm to avoid pit formation during rains or at the time of irrigation. The top surface up to 2–3cm should be enriched with fine, seived and decomposed farmyard manure or compost after sowing. Seeds are sown in lines 4–5cm apart in rabi and 5–7cm in kharif. Sowingshould not be done more than 2–3cm deep. After sowing, the beds are mulched with dry grass or straw or any other material to maintain and preserve the required soil moisture. As and when there is lack of moisture in the bed, it should be watered by the sprinkling can. After the germination dry grass and mulching material should be removed. As and when needed nursery should be protected from heavy rains in kharif season. The continuous covering of nursery favours attack of fungal diseases due to risk of high humidity and heat. Therefore, the seedlings should be covered only when there is rise in damage by heavy rains. To protect young seedlings from heat of direct sun rays, partial shade should also be provided. About 10–12kg seed in rabi and 12–15kg seed in kharif is required to raise seedlings for planting in one hectare. The seedlings are ready for transplanting 6–7 weeks and 8–9 weeks after sowing during kharif and rabi respectively. Seedlings 20–25cm in height are ready for transplanting. Over-aged seedlings result in bolting, taking longer time to start new growth, whereas under-aged seedlings do not establish well after transplanting. The spacing varies from variety-to-variety on the basis of size of the bulbs. Planting by bulbs This is practised to meet the demand of green onion for salad in early winter. Bulbs are dibbled 15cm on the side of 45cm wide ridges or in beds. Another practice is to dibble bulbs in furrows made with country plough. The field is irrigated after forming beds and channels. For planting one hectare, 750kg of medium-sized bulbs are required. Larger-sized bulbs tend to flower early resulting in low yield. In northern India, bulbs from the previous harvest are planted in August or September. The secondary bulbs developing from the mother bulbs find a ready market as green onions early in the season (October–December). Direct sowing Onions can also be grown by direct seeding. Soil is thoroughly pulverized and made free of clods. Varieties with bigger-sized bulbs are grown in rows 30cm apart. Seedlings 6–8 weeks old, may be thinned. For smaller-sized bulbs, sowing can be done by broadcasting and later thinned 5cm each way. A light irrigation is given immediately after sowing. Interculture and irrigation may be repeated after every 10 days. Planting by sets Sets are small-sized onions produced by the seedlings, to mature in the nursery beds as such instead of transplanting them. These are used to get an early crop of onion in some parts of Gujarat, Maharashtra and Rajasthan. Mahsera and Talaza in Gujarat are the areas where sets are raised for local use as well as for supply to other states. For planting one hectare, 5–8kg seed is sufficient to raise enough number of sets in 200m2 area. Nursery is prepared as usual. Mid-January–February is ideal time of sowing. Let the plants remain in the nursery till their leaves fall (till April). By this time plants form small sets due to lesser spacing. Later on dig out the sets. About 1.5–2cm sized, disease-free sets are selected. Very small sets result in more splits, doubles and bolters. Larger-sized sets increase cost of production. The graded sets are stored in hessian cloth bags or in shallow baskets or in racks under properly ventilated conditions. Generally, 10q of sets of 1.5–2.0cm diameter are required for planting one hectare crop. The sets are planted 10cm apart in rows on both sides of ridges spaced at 35–45cm spacing. Sets are normally planted by mid-August to get an early crop by mid-November. The planting, however, can be continued up to mid-September so as to stagger the availability of produce up to mid-December. A light irrigation is given immediately after planting the sets. In multiplier onion, bulbs are first separated and then bigger-sized bulbs are used for planting. Manuring and fertilization Onion needs a heavy dose of fertilizers for a good yield. However, fertilizer requirements depend upon soil type and type of crop. Farmyard manure @ 20–25 tonnes/ha may be incorporated into the soil one month before transplanting. Full amount of P and K and half of N is to be added just before transplanting. Rest of the N is to be given as a single dose 20–25 days after transplanting in case of sowing by sets and multiplier onions, whereas it is given into 2 doses in seedling transplanted onion, first 30 and second 45–60 days after transplanting. In addition to the chemical fertilizers, some other nutrients are also useful for improving onion quality. Zinc application (1–3ppm) increases yield as well as improves quality. Cultural operations As plants are less spaced and roots are less penetrating, it is essential to keep the crop weed-free, especially at the initial stage of plant growth. In onion, hand-weeding in generally practised but once the vegetative growth of the plants is complete, hand-weeding becomes very difficult and expensive also. Therefore, chemical weed control along with a hand-weeding after 45 days is recommended. Baseline @ 1 litre/ha or Stomp @ 3.5 litres/ha immediately after transplanting are quite effective to control weeds. Irrigation Water requirement in general, depends upon plant, its growth stage, soil type and climatic conditions. Onion is a shallow-rooted crop with roots generally confined within 8cm of the soil surface. It is very rare that they go up to 15cm . Water requirement of onion is therefore, less in the beginning. During rainy or kharif season, one irrigation is given immediately after the transplanting, especially in north India. Delay in irrigation may result in seedling mortality up to 80–90%. In kharif crop 8–10 irrigations are sufficient. A late kharif crop requires 12–15 irrigations, whereas rabi crop 15–20. Water is a critical requirement at the time of bulb formation. Its scarcity at this stage can affect the yield drastically. However, excessive moisture favours incidence of purple blotch especially when the vegetative growth is over. Do not let the field remain dry for a longer period, otherwise bulbs may split and crop may have a forced early maturity. Frequent light irrigations at weekly intervals promote proper bulb development and good yield. Sprinkler and drip irrigation systems are also recommended. In rabi season, stop the irrigation when leaves start falling. In kharif crop, stop the irrigation 10 days before digging.

Harvesting & Postharvest management

Onion is ready for harvesting in 3–5 months and 2–3 months after transplanting for dry and green onions respectively. Green onions are harvested when they are just ready for earthing. Plants are uprooted by hand and their roots are cut. They are washed and bundled as per market requirement. The optimum time for harvesting bulbs for sale or for storage from a rabi crop is when leaves start falling. The exact time is one week after 50% leaves have fallen. So optimum harvesting time is when leaves start turning yellow and becoming dry at the top. Bulbs turn red and attain their optimum varietal size. Multiplier onions are harvested when 50–70% leaves have fallen. Before they dry fully, leaves are cut 2–2.5cm above the bulb. After harvesting, a kharif crop should be left in the field for a few days for drying of leaves. Common onion varieties yield up to 250–300q/ha, small-sized pickling type varieties 160–200q/ha, and multiplier onions 150–180q/ha. Onion bulbs that are to be stored in crates are usually thoroughly cured before being placed in storage. The purpose of curing (drying) is to remove excess moisture from the outer skin and neck of onion which helps reduce the infection of disease. This also helps minimize shrinkage and development of skin colour. Therefore, onions should be adequately cured. Time required for curing largely depends upon the prevailing weather conditions. For a kharif crop in north India, when temperature is quite low, curing is done for 2–3 weeks along with the leaves under the sun. If temperature is very low then use drier, blowing hot air at 46°C for 16hr. A rabi crop is cured by covering bulbs with their leaves in the rows in field for 2–3 days, then cutting the leaves 2–2.5cm above the neck and curing under shade for 7–10 days. Kharif and late kharif crops in Maharashtra are cured in the same way as rabi crop except that curing in field is extended by 1–2 days. Small and multiplier onions are also cured similarly. Onions are cured when neck is tight and the dried scales rustle. After curing, onions are graded and classified by grading machine and hand. Before storage, doubled, broken, rotten bulbs and bulbs having undesirable features are removed. To get a good price, grading is practised even after storage also. Outer dry scales generally are removed during grading thereby making bulbs look attractive. Grading and classification are necessary for both local market as well as for export. Delhi market prefers big-sized bulbs; Calcutta, Patna and Lucknow prefer medium-sized bulbs and Bangalore, Bhopal, Jabalpur and Hyderabad markets have demand for medium to big-sized bulbs. Markets of Bhubaneswar, Guwahati and other north-eastern states prefer small-sized onions. Jute bags are used for onion packaging for sending to distant markets by trucks, trains or even by air. Generally 40kg capacity jute bags are used for transport within country, whereas for export, jute bags of 8–25kg capacity are used. Onions should be packed in 14–15kg capacity cane baskets for export purpose.  

Nutritional Value

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Opium poppy ( Papaver somniferum )

Chromosome Number: 22

Taxonomic Classification

Opium poppy is a biennial herb in Eastern Europe. As a crop it is grown as a cold weather annual in subtropical parts of north India. This is a dual purpose crop where seed is edible and highly nutritive. The latex extracted from fully-grown mature capsules contains 40 alkaloids, of which morphine and codeine are best known for their sedative, analgesic, antitussive and antispasmodic properties. It is the best known pain-killer. The crop is grown over 30,000 ha land under an annually renewable license, issued by the Union Narcotics Department in 12 opium poppy designated divisions which fall in Neemuch, Mandsaur and Ratlam in Madhya Pradesh; Chittorgarh, Jhalawar and Kota in Rajasthan and Barabanki, Bareilly, Shahajahanpur, Faizabad, Raibareilly and Gazipur in Uttar Pradesh. The area under cultivation is being continuously reduced, necessitating large import of seed to meet growing demand for culinary purposes. The crop provides livelihood to 2.5 lakh rural families in the region. The latex and seed both are high income-generating items.

Opium poppy is a sparsely branched, annual herb growing up to 150cm height. The main stem is thick and is covered with waxy coating, bearing numerous alternate, stalked, spinisect leaves. The lower leaves are oval-oblong, whereas the upper ones more broader and cordate in shape. The crop bears large variously coloured showy flowers, supported with 8–10cm long stalks 75–90 days after sowing. It produces large, spherical to globular, greyish-green capsules 90–110 days after sowing, studded with numerous light flat seeds. The capsule ends abruptly at the apex, opening by pores beneath the 7–18 stigmatic rays. The seed is mostly white but grey, black and violet coloured seeds are also found in some cultures.

Although opium poppy grows over a wide variety of soils and climatic conditions, it grows best in deep, highly fertile, loamy to clay-loam soils of 6–7.5 pH with adequate irrigation facility. The soil should contain high organic matter to retain moisture. In actual practice, sandy loam and lateritic soils under good management also produce high yield but need more frequent irrigation. The crop prefers moderately cool weather and light showers to foggy nights at rosette stage which support good vegetative growth; but open sunny weather is needed at capsule-formation stage till their maturity. Dry, warm, weather (32°–38°C) during February–March favours good flow of latex during lancing and consequently produces high latex yield. Severe cold spell, frost, hailstorm, cloudy weather, heavy rains and strong winds at (capsule) lancing stage affect latex yield adversely. A wider change in day and night temperature at this period is also inimical to good yield.

A number of old cultivars and land races are in cultivation. A large number of new cultures have been added in the last 15 years. Of the old popular varieties, Dhawla Chota Gothia, Telia, Ranjhatak and Suya Pankhi are common. Jawahar Aphim 16, Chetak and Trishna are high-yielding varieties recommended for Madhya Pradesh and Rajasthan. These produce 55–70kg/ha of latex. Kirtiman and BROP 1 are recommended for eastern Uttar Pradesh. Sweta, Shyama and Vivek are other varieties for getting high latex and morphine yield, whereas Sanchita is for high morphine content in the straw, meant for solvent extraction of capsules, eliminating lancing in the field.

Land is prepared in October to a fine tilth up to 20–25cm depth. Apply 10–20 tonnes farmyard manure along with 40kg each of N, P and K basally at land preparation. It is advisable to apply 20kg of BHC (10%) or Aldrin (5%) in soil to protect from soil-borne insects. For Zn deficiency, ZnSO 4 should be applied at land preparation. It is sown in early-November in western India, and during late-October in eastern Uttar Pradesh when soil temperature is 20°–25°C. The seed rate is 4–6kg/ha and line sowing at 30cm is preferred (facilitating weeding). The seeds are covered with a thin layer of soil and given light irrigation. Seed germination is over in 12 days. The seeds should be treated with Apron sd-35 (2g/kg) or Dithane M–45 (4g/kg) to protect from soil-borne diseases. Use of rakes in lines 20 days after sowing facilitates the emerging seedlings from crust formation. Since it is a heavy feeder of nitrogenous fertilizer add 50–80 kg of N (depending upon soil fertility) is given in 2 split doses at rosette and flowering shoot-bearing stage. The crop is given 7–11 irrigations, depending upon soil texture; the irrigation is frequent between flower bud and capsule maturity stages and the last one is given 3 days before commencement of lancing. However, one more irrigation is given before last lancing when crop is grown over light soils to exhaust the capsule of its latex. Moisture deficiency at rosette, flower bud and capsule formation stages affect growth, size of capsule and its latex and seed yield adversly. Conversely, high soil moisture and fertility allows a wide variety of weeds to infest its crop. Weeding 15–20 days, 45 days and 70 days after sowing keeps the crop weed-free. Chloroturon. (1.5kg/ha) at pre-emergence stage is good to protect initial weed growth.

The latex is obtained by making incision on capsule wall. The capsule is ready for lancing after 20–25 days of the fall of petals. At this stage, the capsule is green, immature but is of fully grown size. It contains 70% of the total morphine synthesized by the plant. The lancing and collection of opium latex are skilled jobs. For this, the field is divided into 3–4 portions so that each part gets a chance for lancing every third or fourth day. The capsule is lanced longitudinally with a special knife, locally called ‘naka' or ‘nastar', which can make 3–4 incisions at a time, about one-twelfth cm apart from each other. The ‘naka' has 3–4 small, sharp blades bound at a short distance, to ensure uniform incision at 1.2mm depth and avoid deeper cut, which otherwise cuts into the wall and spoils the seed crop. Usually,each capsule is lanced 4 times but growers sometimes do more incision if they receive latex on each successive incision. Thus, incision consists of 3–4 parallel cuts, made after mid-day. This induces the incised capsule wall to exude latex which is allowed to remain on the capsule overnight to coagulate, become thicker and is scraped by a blunt-edged knife on the following morning.

The colour of fresh latex varies from milky-white, to smoke-white but in a few varieties pale-pink to bright pink latex is also obtained. Generally, lancing starts from north to south to keep incision facing the sun. The yield of latex and its morphine content is maximum in the first lancing and decreases progressively in subsequent lancing. The terminal capsule yields more latex than lateral ones. The collected latex is of 70–90% consistency and is stored in earthen pots, dried and mixed to make homogeneous complex for storage. It changes into brownish to black in colour. This semisolid produce is stored in closed vessels. All latex produced by licensed growers has to be deposited to field depots of Narcotics Department. The farmers are paid according to designated consistency grade and purity of their produce. Long storage induces oxidation, reducing morphine content between 20 and 50% in 6 months to one-year period. The stored dry latex is transported to Neemuch or Gazipur factories for further purification, separation of alkaloids and making of opium salts for marketing and export.

The Indian produce of opium latex contains on an average 20% of total alkaloids by weight. Of which, 9–14% is morphine, 1.25–3.75% codeine, 5–7% narcotine, 0.4–1.0% papaverine and 0.2–0.5% thebaine .

Nutritional Value

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Orchids ( Cymbidium, Dendrobium, Oncidium and Cattleya species )

Orchids are valued for their long spikes which display a variety of colours and long-lasting flowers. They occupy a prime position among cut flowers. The family, Orchidaceae, consists of 600–800 genera and 30,000–35,000 species, distributed throughout the world.

In India, about 1,300 species are scattered all over India, North-east Himalayas and 600 species are in north west Himalayas of these 300 species are in Maharashtra 130 species in Andaman and Nicobar Islands 70 species and Western Ghats 200 species. Eversince the creation of the first man-made hybrid in 1956, several have been added, totalling to over a lakh.

Genus Cymbidium is now among the top 10 cut flowers of the world market, whereas Dendrobium , the most widely cultivated tropical orchid, is also marching ahead to find a better place in the export market. The Cymbidium is mainly grown in the north-eastern Himalayan region, Sikkim, Arunachal Pradesh and Assam. Tropical orchids are mainly confined to Kerala and some parts of Tamil Nadu. North-eastern Himalayan region and the west-coast of Kerala are the main centres of production of orchids.

The commercial orchids are both terrestrial and epiphytic, with an abundance in epiphytic. Monopodial (having single-stemmed growth) and sympodial (having the appearance of multi-stemmed growth) are equally preferred for commercial cultivation. Sympodial types (Cymbidium and Dendrobium) rank high in the export market. Among the sympodial ones, a major share or the area in Kerala is occupied by Dendrobium hybrids. They can be successfully tried in the foothills of north-eastern states. Other sympodial genera suitable for Kerala are Cymbidium (at high altitudes), Oncidium and Cattleya. Vanda, Arachnis and Phalaenopsis are the monopodial genera that flourish under our conditions. Intergeneric monopodial hybrids— Aranda , Assocenda and Mokara —also perform well.

Climate and soil

Humidity is most important, in determining the growth and production of orchids. Regulation of shade is equally important which warrants attention. Good air movement is also essential for healthy orchids. Since the commercial orchids grown in India are mostly epiphytic, soil condition is not a problem, as long as it does not adversely affect the water quality.

Varieties

Cymbidium , the temperate orchid, is now grown in the north-eastern regions of India. The flower spikes are arching or drooping and display a wide variety of colours. Some of the hybrids of importance are Angelica Advent, Dingwall ‘Lenes' and Peter Pan ‘Greenleaves'.

Since Dendrobium consists of a large number of species (over 1,000), several hybrids have been produced and released for commercial cultivation. Those popular in Kerala are Sonia 17, Sonia 17 Mutant, Sonia 28 Mutant, Hieng Beauty, Renapa, Dorine White, Ekapol Panda, Sakura Pink, Pramot Sabine, Emma White, Kasem White, Mme Vipar, Kasem Gold, PM 11, Waipahu Beauty, Sarifa Fatimah, Walter omae and Jiad Gold.

Salient features and common varieties of other popular genera are as follows:

Arachnis (scorpion orchid) monopodial, requires good sunlight and temperature for growth and flowering. Renanthera is a related genus. Its variety, Maggie Oei, is most popular. On the basis of the colour there are 2 types, ‘Red Ribbon' and ‘Yellow Ribbon'.

Vanda: Its habit is that of Arachins. Based on shape of leaf, terete (cylindrical leaved, pencil Vanda) semi-terete and strap leaved vanda. Aerides and Rhyncostylis are related genera. Varieties: John Clubb, Josephine Van Brero, Norbert Alphonso, Wirat Uchida and Ruby Prince are important.

Phalaenopsis (moth orchid): Monopodial, requires partially shaded conditions. Doritis is a related genus. Varieties: Rose parade, Keith Shaffer, Temple Cloud, Hennessy and Diana Pinky are important.

Oncidium (dancing girl): Sympodial, with or without pseudobulb, loves partially shaded conditions. Varieties: Goldiana and Gower Ramsay are important.

Cattleya: Sympodial, loves partially shaded conditions. Brassavola, Laelia, Sophronitis, Encyclia etc. are related genera. Varieties: Suzanne Hye and Edithe Bow Bells are important.

Propagation

Orchids are grown by seeds, tissue culture and vegetative methods. Though vegetative propagation is a slow process, it is easier to carry out. Monopodial orchids like Vanda and Arachnis can be propagated by top cuttings. In Phalaenopsis, flower stalks give rise to plants. Sympodial orchids— Dendrobium, Cattleya and Cymbidium—can be propagated by division. The shoots growing on the plants, which are called ‘keikis', can also be used. Keikis are very common in Dendrobium. Back-bulbs (spent canes) can also be used as propagules.

In tissue culture, seeds, axillary buds, apical buds, leaf segments and inflorescence axes—can be used. Seed propagation is carried out only in a tissue culture medium because the seeds are extremely small and are devoid of endosperm. Each seed pod contains millions of seeds and the time taken for maturity depends on the genus. The most widely used medium is Knudson C. Meristem culture, which enables the production of a much higher number of uniform plantlets in a short period is now used for large-scale production of orchids. The commonly used media are MS, Vacin and Went and Knudson C.

Cultivation

Planting

Earthern pots, baskets, tree fern blocks, wooden trays and whole husk of coconut are common containers used for planting orchids. Sufficient drainage is very essential for orchids. Therefore, holes of appropriate size are made in containers, both at the bottom and on the sides. The size of the container should be proportionate to the size of the plant and its growth habit. Orchids can be planted on the ground too, in shallow trenches filled with media.

The medium used for growing orchids should allow good aeration and drainage. It should not absorb too much water and should not degenerate easily. Broken bricks, gravel, tile bits, charcoal, coconut husk bits and tree fern are components of media used for growing epiphytic orchids. The components are washed thoroughly before filling in pots. For terrestrial orchids, a judicious mixture of humus, leaf-mould, dried manure, chopped fern fibre and sphagnum moss suffice.

For epiphytic orchids, the pots are filled with the media and the plants are placed over it, exposing the roots. In sympodials, the plant is placed near the edge of the pot, the growing point facing towards the centre. A monopodial orchid is placed in the centre of the container. If necessary, a stake may be used to keep the plant in position. When growing on tree fern rafts, the plant is tied with a soft copper wire. The whole plant with pot may be dipped in water after planting and thereafter watered judiciously. The plants can also be grown on raised platforms over appropriate media directly or in pots.

Orchids can be grown in hanging pot or baskets too. Where, lighter media like charcoal, coconut husk and tree fern fibre are used.

In Dendrobium, the planting density should be 100,000–150,000 plants/ha. Sympodial orchids, in general, prefer a very close planting and crowded growth.

Manuring and fertilization

Orchids require both major nutrients and minor nutrients. The relative proportion of N controls the vegetative or the productive phase of the crop. A higher level of N for stimulating vegetative growth and a lower level for flowering. Ready-made fertilizer formulations are available in the market to satisfy these requirements. A low concentration (0.1–0.2%) of these nutrients should be applied frequently as whole plant spray. Spraying 2–5 times a week is generally ideal. In flowering plants, care should be taken to see that the plants are kept free from fertilizer application at least 3 days prior to harvest of flowers. Otherwise the keeping quality of flowers may be affected. Care should also be taken to see that sufficiently grown up plants are not fed with high level of N. This may result in production of shoots or mixed spike instead of a quality spike. Micronutrients help improve the quality. These are applied once a month.

The chemical fertilizers are to be properly balanced with organic manures—cowdung, cow's urine, groundnut cake and neem-oil cake. They are to be diluted before application. Since urine contains high level of salts, a dilution of 1:25 is necessary. For others 1:10 dilution and subsequent storing for 4–5 days before application is ideal. One spray a week with organic manure is enough.

Aftercare

In both the locations (North-eastern states and Kerala), salubrious natural conditions exist for the growth and development of orchids. However, better post-planting attention is required to get healthy plants and quality flowers. Check the support given to plants, remove decayed and dried up parts, check water stagnation, provide good ventilation, remove weed growth on the media and exposing the roots are the main operations to be done.

The monopodial types— Vanda , Arachnis and Aranda —prefer open conditions with plenty of sunlight. The Dendrobiums , Cymbidiums , Cattleyas and Oncidiums should be grown under partial shade. The thumb rule is to provide maximum light which they can withstand, without adversely affecting their health. Care should also be given to see that the shading materials should not hinder the air movement. The ultra violet (UV) stabilized agro-shade nets are ideal for regulating shade, which are available at varying shade intensities. Green or black colour is usually preferred.

Irrigation

Besides improving the humidity of the environment, application of water should also help in washing out the deposits of fertilizer residues which may otherwise be harmful to the plants. In summer, 2 irrigations are ideal. A heavy irrigation in the morning, followed by a dry period and a light irrigation in the late afternoon is preferred. The dry spell checks disease incidence and spread. A high pressure-low volume method of irrigation, such as mist irrigation, or fogging system (micro-sprinkler) is ideal. The quality of water is also important. Water should have a near neutral pH and should be free from dissolved salts.

In both the locations mentioned, heavy rains prevail for a long spell. This not only reduces light incidence but also may cause diseases due to direct impact of rains. Providing shade-nets at 2 levels during summer to give the required shade and replacing the lower shade net during rainy seasons with UV film, is highly beneficial under such conditions. The UV film allows more light to penetrate and also protects the plants from direct rains.

Harvesting & Postharvest management

In most of the genera, orchids take more than a year to come to flowering, after planting out from the flasks. Medium-sized plants take about 6 months to start flowering. Initial spike is very small and these are preferably pinched off to improve the quality of spikes.

The spikes of orchids are harvested when a few buds on the top remain unopen. Under tropical conditions, harvesting during early morning or evening is preferred. Leaving a small length of the stalk, the spikes are cut using a sharp knife. Application of fungicides to the open wounds of the plant prevents possible infection.

Yield of spikes varies from genus to genus and variety to variety. On an average, 6–8 spikes are available from commercial varieties of Dendrobium. In Sonia 17, more number of spikes are produced in Kerala. For a period of 2–3 months with the onset of south west monsoon, there is a decline in flowering in most of the varieties.

The harvested spikes, also known as stems, are immediately put in a bucket of water. The cut end is fully immersed. These are then taken to the packing house for grading and packing. The cut ends of the spikes are wrapped with wet cotton and tied with a rubber band. Alternatively, the cut ends are inserted into a plastic tube containing water.

Number of buds to be retained on the spike and grading vary in different places. It is usually 25–50% of the total flowers in a spike. In spikes producing larger number of flowers, as in Dendrobiums , those having less than 5 flowers are not usually preferred.

Boxes used for packing different types and grades of orchids vary in their size. Use strong cartons of adequate size for better handling of flowers. About 50 flower spikes are packed in a single box. It is desirable to keep the boxes in refrigerated trucks during transport. They are also to be stored in refrigerated rooms. A storage temperature below 7°C causes chilling injury to the flowers.

After reaching the destination, the flower spikes are carefully removed from cartons and placed in water. It is desirable to cut and remove a small portion of the base of the spike once in every 2 or 3 days to help better absorption of water. Usually no chemicals are used in the holding solution. However, use of 8-Hydroxy Quinoline Citrate (100–200ppm) with sucrose (3–5%) and boric acid (0.1%) improves the vase-life.

Pricing of spikes depends on the type of orchid and the grade of the spike. In Kerala, the cost of one Dendrobium spike ranges from Rs 10 to Rs 25, depending on the grade. For Oncidium and Vanda, the usual pricing is between Rs 10 and 20.

At present most of the flowers produced in the country are fed to internal markets. There are agencies like societies and traders who arrange for collection of spikes at a reasonable price. These societies and traders in turn take the flowers to bigger traders who are located in certain major cities. The flowers are then passed on to wholesale agents in metroplitian cities who then dispose the flowers to retailers or consumers directly. Certain agencies also take up value addition by making floral arrangements and bouquets.

Physiological Disorders

Though orchids are perennial in their growth habit, sympodial orchids usually show a setback in growth after a period of 4–5 years. In Dendrobiums the leaves shed and the canes appear bare. Flowering is also very shy. This physiological setback is recovered if repotted. Application of a high concentration (5,000–10,000ppm) of an auxin also helps.

At times, some of the buds do not open, which may also result from high fluctuation in humidity that is experienced in summer months. Wetting the floor (not the plants) during noon time checks this. Occasional wilting of certain flowers on the spikes could be due to loss of pollen, sometimes caused by insects. Shedding of pollinia could also happen during transport.

Certain defects are inherent and genetic. Yellow streaks on the leaves are found due to mutations. Stunted plants, malformed leaves and ill developed spikes also appear due to genetic changes, occurring sometimes due to unscientific tissue culture techniques and conditions. It is necessary to remove and destroy such plants.