Everything you need to know about grapes cultivation, production and growth. Learn about:- 1. Introduction to Grapes 2. Climate and Soil Required for Growing Grapes 3. Propagation and Rootstocks 4. Planting and Training 5. Pruning Time 6. Manuring and Fertilization 7. Irrigation 8. Harvesting and Postharvest Management 9. Varieties.
Contents:
- Introduction to Grapes
- Climate and Soil Required for Growing Grapes
- Propagation and Rootstocks of Grapes
- Planting and Training of Grapes
- Pruning Time of Grapes
- Manuring and Fertilization of Grapes
- Irrigation of Grapes
- Harvesting and Postharvest Management of Grapes
- Varieties of Grapes
1. Introduction to Grapes:
The grape (Vitis vinifera L.) is a non- climacteric fruit and is grown under a variety of soil and climatic conditions in three distinct agro- climatic zones, namely, sub-tropical, hot tropical and mild tropical climatic regions in India. Grape is a deciduous crop. Its natural habitat is temperate climate.
It was introduced into north India from Iran and Afghanistan in 1300 AD by the Muslim invaders; and into south India in 1832 by the Christian missionaries from France. However, grape was known in ancient India though it was not commercially cultivated until the 14th century. Wild grapes grown in Himachal Pradesh were used to prepare local wine.’
In India cultivated grapes are believed to have been introduced into the north of India by the Persian invaders in 1300 AD, from where they were introduced into the south (Daulatabad in Aurangabad district of Maharashtra) during the historic event of changing the capital from Delhi to Daulatabad by King Mohammed-bin-Tughlak.
Ibn Batuta, a Moorish traveler who visited Daulatabad in 1430 AD, reported to have seen flourishing vineyards in south India. Grape was also introduced in the south into Salem and Madurai districts of Tamil Nadu by the Christian missionaries around 1832 AD and into Hyderabad province by HEH, the Nizam of Hyderabad in the early part of the 20th century.
From Delhi, Daulatabad, Madurai, Salem and Hyderabad, grape cultivation spread to different parts of the country. Presently grape cultivation is concentrated in the peninsular India, accounting for 90% of the total area. Major grape-growing states are Maharashtra, Karnataka, Andhra Pradesh, Tamil Nadu, and the north-western region covering Punjab, Haryana, Delhi, western Uttar Pradesh, Rajasthan and Madhya Pradesh.
About 85 per cent of the total production, irrespective of the variety, is consumed fresh. About 120,000 tonnes of Thompson Seedless and its mutants, namely, Tas-A-Ganesh, Sonaka and Manik Chaman are dried for raisins. Some 20,000 tonnes of Bangalore Blue are crushed to make juice, and 10,000 tonnes of Bangalore Blue, Cabernet Sauvignon, Chenin Blanc, Chardonnay, Merlot, Pinot Noir and Uni Blanc are crushed to process into wine.
2. Climate and Soil Required for Growing Grapes:
Grape is a subtropical fruit that grows well in dry summer. The vines shed their leaves and rest in winter, put forth new growth in spring and mature in summer. Grape does not thrive in regions having humid summers. Temperature, humidity and light are important for grapes. Areas with high humidity and high rainfall are not suitable. The climatic requirements of vinifera are different from those of labrusca grapes.
Mild temperature, not exceeding 35 °C in summers, impairs the fruiting of vinifera grapes, particularly, in Thompson Seedless. Higher night temperatures (above 25 °C) during ripening hamper the colour development in coloured grapes. Cool nights and hot days even though congenial for coloured grapes, pink pigmentation develops in green grapes if the diurnal differences are more than 20 °C during ripening.
Under high humid conditions, the vines put forth excessive vegetative growth at the expense of fruiting. Berries do not ripen properly. Disease incidence is high. The total amount of rainfall is not the criterion, but the timing, frequency and duration of rainfall are important considerations for grape cultivation.
Rains associated with cloudy weather and poor sunlight during 45-60 days after back pruning in the tropical India reduce the fruitful buds in a vine. Rainfall during flowering is most unsuitable for grapes because the panicles are damaged by downy mildew. Similarly, rains during ripening cause berry cracking and rotting.
The soil with good drainage and water-holding capacity in a pH range of 6.5-7.5 is ideally-suited for grapes. Presence of excess salts, particularly sodium and free calcium is detrimental for grapes. The grapes are grown best on light, friable loamy soils with free drainage. Heavy soils are unsuitable.
In India, it is grown on a variety of soils like alluvial in north, heavy black clay in Maharashtra and north Karnataka, red loam in southern Karnataka and Tamil Nadu and very light sandy locally called ‘Chalka’ soils in Andhra Pradesh.
3. Propagation and Rootstocks of Grapes:
Grape is mostly propagated by hardwood stem cuttings. Since the non- prevalence of Phylloxera or nematodes, rootstocks is not employed, but in recent years, the ‘Dogridge’ rootstock is being employed to combat soil and water salinity problems.
They are multiplied by the rooting of hardwood cuttings. Growers obtain the hardwood cuttings (diameter of cuttings should be 8-10 mm with 4 nodes) from elite vineyards and raise their own nurseries. Well matured canes are selected.
In nematode-prone soils, the rootstock 1613 can be used for Anab-e- Shahi or Thompson Seedless. Cuttings are mostly obtained from October pruning in the peninsula. Thompson Seedless roots are poorer than Anab-e- Shahi or Bangalore Blue.
To increase the rooting of stem cuttings fresh cuttings are soaked in running water for 24 hours to leach out the water-soluble rooting inhibitors. Then soak or dip them to cover the basal buds in IBA solution for overnight (500 ppm IBA solution or for quick dipping use 2000 ppm for 10 sec.) before planting in the nursery or directly in the field.
It is also a practice to plant the cuttings in situ when three to four cuttings prepared and treated as above are planted at each spot in the main field. Soil drenching with chlorophyriphos 0.1 per cent is a practice to safeguard the cuttings against termite damage.
Hardwood cuttings of the ‘Dogridge’ rootstock are subjected to rooting, preferably in polybags of 15 x 25 cm. The rooting media should have 30-40% well-decomposed cattle manure to retain moisture and similar proportion of sand to provide drainage. The beds or polybags should be under partial shade.
Cuttings may be covered with green twigs to provide shade. The beds or rooting medium should be treated with Chloropyriphos or Furadan granules to prevent termite damage. Light frequent watering is to be given to the cuttings. After rooting, one god cutting is retained at each spot. Gap filling should also be done at this stage.
Rooted cuttings of this rootstock are planted in the main field during February-March. The desired scion variety is then grafted/budded on the rootstocks in the field by wedge grafting/chip budding. Wedge grafting is more common and the best time for the operation is September-October, while June-July is the suitable time for chip budding.
4. Planting and Training of Grapes:
Before planting the rooted/unrooted cuttings in the main field, the land is cleared of all bushes and leveled. The land is tilled and laid into plots of 120 m x 180 m separated by 2-3 m wide roads in continuous trenches.
Land within a plot is leveled perfectly to have a gradient of less than 1 per cent in any direction to ensure uniform discharge of water through the emitters of drip irrigation systems. The pits/trenches are filled with farmyard manure, green manure/leaf-mould, bone-meal (1 kg), superphosphate (1 kg) and allowed to settle by watering.
Trenches of 75 cm width, 75 cm depth and 118 m length in a north-south direction with a gap of 3 m between trenches should be prepared. They should be closed with topsoil, up to a height of 45 cm after 15 days exposure to sun.
The remaining gap is filled with a mixture of soil, cattle manure, single superphosphate, sulphate of potash and micronutrients. The soil for every running meter length of the trench should be supplied with 50 kg of cattle manure, 2.5 kg of superphosphate, 0.5 kg of sulphate of potash and 50 g each of ZnSO4 and FeSO4.
Planting Season:
September to October months are the best season of planting of rooted cuttings of cultivated varieties. The rootstocks should be planted in February-March.
Spacing:
Spacing depends on the varieties and soil fertility. For vigorous varieties it is 6 m x 3 m or 4 m x 3 m and 3m x 3m or 3m x 2m for less vigorous varieties. Anab-e-Shahi and Dilkhush vines are spaced at 3.3 m x 6.6 m or 5.0 m x 5.0 m.
The spacing of vines of seedless varieties varies from 1.2 m to 2.0 m within a row and 2.7 to 3.6 m between rows when trained to T or Y trellis. For Thompson Seedless, the spacing of 1.8 m x 2.5 m and 1.8 m x 3.0 m is ideal for bower and ‘Y’ trellies trained vines respectively.
Training:
There are several systems like training-head, kniffin, telephone, V, expanded y and gable – are in adopted in India. The following are the popular systems Bower, Telephone and Flat Roof Gable systems.
i. Bower System:
This system of training is suitable for vigorous varieties like Anab-e-Shahi, Bangalore Blue and Gulabi. For varieties like Thompson Seedless and Tas-A-Ganesh where the vine vigour and excessive foliage density is observed and affects the productivity adversely, therefore, this system is not suitable.
ii. Telephone System:
T-trellis is used in this system of training. With three top wires and T shaped supports, the trellis looks like a telephone pole and wires and hence the name.
This system is suitable for moderately vigorous varieties like Thompson Seedless and other seedless cultivars in about 25-30 per cent of the vineyard area in Maharashtra. Yields in this system are less than the bower.
Flat Roof Gable System:
This system is popular in States like Maharashtra, Andhra Pradesh and Karnataka. The disadvantages of this system can be eliminated by combining the advantage of bower and the extended Y systems. An inter-connected Y trellis forming a flat roof gable is being adopted for this system.
It is particularly followed for vigorous vines (vines grafted on rootstocks). The bunches are protected from direct sunlight and well exposed to sprays of pesticides. The clusters hang within the reach of the worker of an average height.
5. Pruning Time of Grapes:
In north India, vines are pruned in winter (December-January). Hall of the canes are pruned to renew spurs and the rest for fruiting canes. One or two buds from the cordon (arm) are retained in renewed at spurs and 12 buds are retained on fruiting canes.
The number of buds left on fruiting canes depends on variety and thickness of cane. Thick canes are pruned longer and the thin shorter. The fruited canes are pruned to renewal spurs and the canes developed from renewal spurs are pruned to fruiting canes in the next winter.
There are 3 distinct pruning practices common in India which depend on the cropping in the three grape growing regions.
In, vines are pruned but only one crop is harvested. All canes in a vine are pruned back to single node spurs in March-May to develop canes and the canes are forward pruned in for fruiting. The number of nodes retained on a cane varies with the variety and cane thickness. There is no scope to prune earlier than October and later than November due to unfavourable weather conditions.
In Maharashtra, Andhra Pradesh and north Karnataka, vines are pruned twice (April to October). The April pruning is generally termed as back pruning or foundation pruning. While October pruning is called fruit pruning or forward pruning. All the canes are pruned to spurs at back pruning, irrespective of the variety or cane thickness.
6. Manuring and Fertilization of Grapes:
Vines are grown in either sandy loams or heavy clays soils, therefore use of organic manure for these soils is important in India because organic manure increases its moisture-holding capacity.
Heavy dose of cattle manure is applied to improve soil structure and to about 25-50 tonnes of well-decomposed cattle manure, 5 tonnes of oil cake (deoiled) and 1,200 kg of organic mixture should be applied every year in a hectare crop. When such organic nutrients are applied, the inorganic doses are proportionately reduced.
A standard dose of 500:500:1000 kg of N, P2O5 and K2O per hectare is followed in light sandy soils, while 660:880:660 kg are applied for heavy clay soils. The annual dose is fixed based on the petiole analysis carried out at 45 days after spur pruning.
While 40 per cent of the annual dose is given through organic sources, 60 per cent is given as inorganic fertilizer. Calcium ammonium nitrate is usually not used. Sulphate of potash is the only source of potash used in place of muriate, particularly in heavy clay soils.
Application of soluble fertilizers through drip irrigation is also common. The dose of soluble fertilizer is as follows:
Potassium and nitrogen (phosphate is required less) are the two important elements which are required for the good growth of vines P is required at the time of fruit-bud formation. The requirement of N becomes less at this time. The N is mainly required during shoot growth (fruiting season). Whereas K is required after bud differentiation for shoot maturity and increasing the size of fruit-bud. It is also required after berry set until ripening.
For soils of Maharashtra and north Karnataka addition of P and less K are required for Thompson Seedless grape. The soils of these regions are rich in K and fix more P.
Petiole Nutrient Contents:
To judge the Petiole nutrient contents the petioles of leaves at fifth node from base are sampled on 45th day after back pruning, while those of leaves opposite to flower clusters at full bloom are sampled after October pruning in south India. Sampling should be done only at full bloom.
Nutrient applications in the subsequent years should be based on these petiole nutrient standards.
Mg deficiency is universal. For recovery of nutrient deficient in soil about 100-200 kg of magnesium sulphate/ha/year should be applied depending upon the severity of its deficiency. While 50 kg is applied after 30 days of April pruning, the rest is applied in 2 splits during the fruiting season once at berry set and again after a month.
Magnesium is to be applied to soil at least one week prior to potash application to increase its uptake.
Black soils are Iron deficient therefore, foliar application of 0.2% ferrous sulphate solution or chelated iron compound is recommended.
7. Irrigation of Grapes:
Grape is a shallow feeder. Light and frequent watering is better for grapes. Water requirements of grape are very high during berry growth. This period coinciding with hot and dry weather, more water is required at this stage. Least water is required during fruit-bud formation. This period if coincides with cloudy weather and rain, watering is totally to be stopped.
Reduced irrigation during ripening, i.e., (one moth prior to harvesting) improves the quality of grapes and hastens ripening. Too much stress during ripening can also increase the berry drop at and after harvesting.
Currently due to the shortage of water, grapes are irrigated through drips. The number of drippers/vine and their placement are very crucial in drip irrigation. The active feeder root zone is to be wetted by the water discharged through the emitters.
Since the wetting pattern is more horizontal than vertical in clay soils but more vertical than horizontal in sandy soils, more emitters with low discharge rate for longer duration are advisable to get good results with drip irrigation in sandy soils.
Inadequate wetting of root zone reduces shoot vigour and weakens the vines, gradually they develop deadwood and go barren 7-8 years after planting. The quantity of water to let through drip irrigation daily depends not only on the stage of growth of the vine but also the evapotranspiration in a vineyard.
Grape is sensitive to chlorides and total salts content in irrigation water. Water with electrical conductivity of less than 1 mmhos/cm, chlorides less than 4 m.e./litre, sodium adsorption ratio less than 8.0, residual sodium carbonate less than 1.25 m.e./litre and boron less than 1.0 mg/kg is considered safe for irrigating grapes.
Raising a bund of loose soil to a height of 1′ along the vine rows and mulching the soil around the drip zone by sugarcane trash or paddy straw can conserve the soil moisture and save irrigation water.
Weed Control of Grapes:
Farmyard manure and compost are the major sources of weed seeds from outside. The problematic weeds in vineyards are Bermuda grass (Cynodon dactylon) and nut grass (Cyperus rotundus). The weed intensity is less in bower trained vineyards.
Mechanical control is most common means of weed control in India. Dhaincha and sunhemp are grown as intercrops to check the weeds in vineyards trained to T, V or Y trellises. Post-emergent weedicides-Paraquat (7.5 kg/ha) or Glyphosate (2.0 kg/ha), is also recommended. Glyphosate offers a long time control of weeds as compared to Paraquat.
Growth regulators – CCC, GA and hydrogen cyanamide – are being used commercially in grapes. The CCC is used to suppress the vigour of vines and increase the fruitfulness of buds. It is sprayed at 500 ppm concentration at 5- leaf stage after back pruning. If weather is cloudy, cool and rainy, it is sprayed on the foliage once again at 10-leaf stage.
Gibberellic acid (GA) is used invariably in all seedless varieties. It is sprayed at 10 ppm to elongate the clusters, 22-25 days after forward pruning (4-5 leaf stage). It is also sprayed on clusters @ 40 ppm at 50% bloom stage for thinning the berries.
For increasing the berry size, the clusters are dipped in 60 ppm GA alone or in a mixture of GA (30 ppm) with 10 ppm BA or 2 ppm CPPU at pearl millet or bajra grain- sized berries and again at redgram sized berries. Care must be taken not to treat the clusters with GA before bajra grain-sized berries. Otherwise, berries of uneven size from a cluster.
For increasing berry size, vines are girdled. Girdling is a process of removing 2-3 mm wide strip of bark around the stem without injuring the wood. This is also to be done at the bajra grain-sized berries.
Hydrogen cyanamide is used to hasten and increase the bud-break at winter pruning. Buds are swabbed with cotton soaked in 1.5% solution of hydrogen cyanamide 48 hr after pruning. Hastening the bud-break with hydrogen cyamide also hastens the ripening of grapes in the north. Thiourea (4.0%) mixed with 1% Bordeaux mixture is also used to increase bud-break in south.
Concept of Double Cropping in North India:
In the Southern and Western parts of the country, where vine remains evergreen, the grape growers are in a great benefit and have to prune the vines twice a year to get two crops annually. In Western India, severe pruning is done in March after harvesting to encourage fresh vegetative growth. The crop from this growth ripens at the end of October but the fruit is poor, thus, the crop is not common. A second light pruning is done in October and the crop is harvested in March.
In the northern India, vines go into dormancy during winter because of distinct summer and winter seasons. The scientists were of the opinion that summer pruning will not be able to produce second crop. Grapes are being grown since long in countries like Afghanistan, Iraq, the Mediterranean Coast, California and parts of Southern Australia where the vines remain dormant during winter and put forth growth only once in spring. At present also, only one crop is taken. Same is the case of northern India. Now, a new thinking has emerged, that is to obtain two crops (winter and summer) with the technique of double pruning.
The idea behind this is to retain fruit on the vine for a longer period with no risk of rain damage as it is a major limitation to the summer crop. Trials have been undertaken at different places in Punjab and Haryana with different dates of pruning i.e., 1st, 10th, 20th and 30th July on Perlette and Tas-e-Ganesh varieties. It was found that 10th July was the best date of pruning. However, the yield is very low in comparison to the summer crop. The trial may prove helpful for improving yields and having fruit during winter also with better quality and without risk of rain damage.
Beauty Seedless grapes in the arid-irrigated region of Punjab can give two crops in a year. Pruning for the summer crop has to be carried out during the first week of February and for the autumn crop from 20th-30th June. The autumn crop is harvested from mid-September to mid-October. Alternate sprays of Bavistin (0.1%) and Bordeaux mixture (2:2:250) are applied at weekly intervals during July and August to protect this crop from anthracnose.
Bud Differentiation:
Normally, the grapevine forms compound buds at each node all along the length of its shoots. The compound bud consists of 3 to 5 buds, in some cases upto 6 buds as seen in Anab- e-Shahi cultivar. The buds are enclosed by the common protective scales and appear as one large bud called ‘eye’. When the vines leaf out in the season, one of the buds (usually the middle one or primary bud) bursts open. In the case of death of the primary, the accessory buds bursts open as laterals.
The buds of the grapevine are classified as leaf bud and fruit bud depending upon the nature of the structure they contain. The leaf bud is a rudimentary sterile shoot which upon leafing out gives a vegetative shoot. The fruit bud contains a shoot having both rudimentary leaves and flower clusters or inflorescence primordia which could be easily distinguished under the stereo microscope or magnifying lens prior to pruning for the subsequent crop.
The rudiments of the flower clusters are formed during the season preceding the year in which the fruiting takes place. The differentiation that results in the formation of fruit buds begins in the end of April under Punjab conditions in Perlette. The differentiation of the buds starts in lower part of the shoot, which is farthest along in their development.
The process of bud differentiation proceeds rapidly once this process starts and by the end of June more than 80 per cent of the buds from the nodes 1-10 get differentiated. The time of fruit bud differentiation depends upon the geographical location of the place and the cultivar involved. In California, the differentiation of the buds in Thompson seedless starts in early June at Davis.
The calyx, corolla, stamens and pistil are differentiated in the order named. The calyx is discernible on the side of the merismetic tissue of the primordia of the flower one week after leaving out. The development of the parts of the flower is very rapid under tropical conditions. At Hyderabad, the differentiation of floral parts in Anab-e-Shahi grape was regular in the order of calyx, corolla, stamens and pistils after bud burst.
The calyx initiated on the 5th day after bud burst and developed fully by 7th day. Corolla was initiated on 7th day and was fully developed by 9th day. Stamens initiated on 7th day developed as a pad like structure by 9th day and differentiation into anthers and filaments by the 11th day. Initiation of the carpel was initiated on 11th day and attained full development by the 13th day with two ovules appearing clearly inside the ovary.
Girdling:
Girdling was introduced into Greece accidentally as a means of improving the set of Block Corinth in 1833. Girdling as practical in commercial vineyards consists in removing a narrow ring of bark entirely around some member of the vine like arm or cane. The common width is 4-5 mm. Girdling of the trunk affects the whole vine while girdling a cane affects only the shoot supported by it. It is essential that the ring be completely removed and even if a small portion of the bark is left, there is no effect. The immediate effect of a complete girdle is to interrupt the supply of carbohydrate and hormones so that their level increases in the parts above the girdle.
The width of the girdle should be such that the wound heals in a short time. It is specially true when the trunk is girdled otherwise restricted food supply to the roots results in death of the vine. Similarly removal of wood below the bark injures the vine. Vines are girdled to accomplish one or more of the three objectives viz. to improve fruit set, to increase berry size and to advance maturation.
Fruit set in variety like Perlette can be improved by girdling the vine before blooming. Sizing of the Seedless cultivar like Thompson Seedless and Perlette can be hastened and their ultimate size can be appreciably increased by girdling timed to be effective during the period of rapid berry enlargement. If girdling is done to improve berry colour or enhance ripening, the girdle must be open and effective during the early part of the ripening period.
Barrenness:
It is a major problem in grapevines found by the growers in North West Indian plains. The problem is sometimes so acute that vines are left with too few canes after pruning. The apparently healthy canes and arms when given cuts are observed to be dry or partially so. The vines do not bear flower bunches and if a few bunches are found, their size is small.
The lack of flower bunch formation can be either due to lack of flower bud formation or their subsequent death. The cause of death of the floral primordia was reported to be shading. The excessive foliage creates such ecological conditions due to which some saprophytic fungi turn into parasitic leading to the death of tissues. The excessive foliage is due to over-fertilization especially with nitrogen. Barrenness is a common phenomenon in Anab-e-Shahi cultivar of grapes.
In this cultivar, loss of floral primordia was found to be a factor contributing to barrenness. The fruitfulness of a bud varied both with the diameter of the cane and its nodal position. The fruitfulness of canes declined when the cane diameter increased or decreased from 1.2 to 1.4 cm. In most fruitful canes, buds at 9th and 10th nodal position had invariably floral primodia. Fruitfulness was more uniformally distributed over various nodal positions in canes of medium vigour but for low vigour canes, it was mostly confined to middle nodes.
With increase in diameter of canes, a decrease in the percentage of floral buds was accompanied by an enhancement in dead buds, but no change in vegetative bud counts. This shows that floral buds were susceptible to death with increase in cane diameter beyond 1.2 cm. The loss of floral primordia occurred between February-March.
Varietal differences have also been reported in loss of floral primordia. The maximum number of infected buds were found in Perlette (77%) followed by Anab-e-Shahi (37%), Himrod (34%) and Thompson Seedless (17%). In Perlette and Himrod, low bearing may be due to flower bud mortality alone but in Anab-e-Shahi and Thompson Seedless the flower bud differentiation is a part of the problem.
There are reports which indicate that syndrome of barrenness is associated with drying of canes. The mortality of the canes extended to the secondary arms of the vine and in some cases even to the primary arms. The removal of all the dead tissue evidently necessitated extensive pruning. There is a close and highly significant relationship between the vigour of a vine and the mortality of its canes. The intensity of mortality is very acute in Anab-e-Shahi trained on bower which gives about 12 kg of dead wood per vine.
The death of flower buds can be checked by using some agronomic measures such as by discouraging excessive vegetative growth and by decreasing azotic fertilization. The excessive growth of the vines can also be controlled by the application of 2000 ppm CCC coupled with removal of dead wood. CCC should be sprayed in mid-October. A simple removal of dead wood at monthly intervals from mid-October to mid-January was observed to be helpful in reducing the mortality of canes.
8. Harvesting and Postharvest Management of Grapes:
Grapes are harvested when fully ripe, since they do not ripen after harvesting. In seeded grapes, the seeds become dark brown when they are fully ripe, while in seedless varieties, their characteristic berry colour develops fully.
The yield potential of grape in India is highest in the world. Grape variety Anab-e-Shahi has recorded yield as high as 92 tonnes/ha, whereas Thompson Seedless has 48 tonnes/ha. The average yield of Anab-e-Shahi and Bangalore Blue is 40-50 tonnes/ha, while that of seedless varieties is 20 tonnes/ha.
Grapes should be harvested during cool time of the day. Harvested grapes are trimmed, graded and packed. For local markets, grapes are packed in bamboo strip baskets using newspaper and grape leaves as cushioning material. One basket contains 6 kg of grapes.
For distant markets (within the country), wood or corrugated cardboard boxes are used for packing. Old newspaper, hay and paper shreds are used as cushioning material. The size of packing is 6 or 8 kg in wood boxes and 2 or 4 kg in cardboard boxes. Transport of grapes is mainly by trucks.
Grapes are exported to middle-east, Europe and south Asian countries. Grapes are packed in ventilated cardboard boxes using dual release sulphur dioxide releasing pads (grape guard) as an in-packing material to check the postharvest diseases during transit and storage.
Strict cold chain is maintained right from harvesting by precooling and cold storage. Boxes are stored at 0°-1°C temperature and 90-95% relative humidity in cold storage. They are transported by sea in refrigerated containers.
Most of the grapes produced in India, irrespective of variety, are consumed fresh. Negligible quantities of Bangalore Blue are crushed to make juice and wine for household consumption. Wine is also produced in India with French collaboration by some private industries growing certain French varieties.
Raisins are the only processed products in India. Approximately 30% of seedless grapes are dried to produce 15,000 tonnes of raisins. Golden bleached raisins are produced by shade drying the clusters after dipping in either boiling solution of sodium hydroxide (0.2-0.3%) and exposing to sulphur fumes. Dipping in soda oil (dipping oil) containing ethyl oleate and potassium carbonate and shade drying is the most common method of preparing raisins in India.
Seeded grapes of Anab-e-Shahi are also dried in very small quantities to make raisins.
9.
Varieties of Grapes:
In India, the commercial varieties were introductions from abroad. Two wild species, namely, Vitis lanata and V. riparia are reported from north-western Himalayan foothills. The commercial varieties are both seeded and seedless types.
A. Seeded Cultivars:
1. Anab-e-shahi:
Probably, the variety is originated from a bud sport because it has a satellite chromosome. The variety id productive successful from commercial point of view and yield over 12-16 tonnes/ha/year in India. The attractive bunch is large fruit with good shipping quality.
2. Bangalore Blue:
It is a hybrid between V. vinifera x V. labrusca. The size medium in vigour and yield. The fruit bunches are small and compact, dark blackish purple in colour with uniform ripening. The fruits are used for the table purpose, preparation of juice and wine. It is hardy and disease resistant variety.
3. Black Champa:
It has been developed at the Indian Institute of Horticultural Research (IIHR), Bangalore. The fruits are vigorous with medium yielding capacity. The seeded grape of excellent quality is suitable for table juice and red dessert wine. It is susceptible to cracking and rotting during rains.
4. Cheema Sahebi:
It is a selection from open pollinated seedlings of Pandhari Sahebi. The fruits are vigorous and give a very heavy yield. The fruits are aggregated in long bunches which are long, conical and shouldered with medium-sized, oval and pale. The shipping quality is poor due to weak pedicellar attachment. It is a late-ripening cultivar.
5. Gulabi:
It is also known as Karachi, Paneer Drakshi and Muscat. It resembles Muscat Hamburg of Australia. The vine is medium in vigour and yield; bunches are small and loose with deep purple, small and spherical berries. It has thick- skinned berries which attribute to good keeping quality. It has a muscat flavour. The ripening is early and fairly uniform.
B. Seedless Cuitivars:
1. Perlette:
The fruits are of medium in size, whitish green and spherical. Fruit-flesh is soft and with mild muscat flavoured. They can be stored for long time. The fruits are small and underdeveloped berries (shot berries) are scattered all over the bunch is a major defect.
2. Pusa Seedless:
It was developed at the Indian Agricultural Research Institute, New Delhi. Its origin is unknown. Its several characters are similar to that of Thompson Seedless variety. Vine is vigorous and medium yielder. Apart from table purpose, good quality raisin can also be prepared from it. It has good keeping quality.
3. Thompson Seedless:
It is one of the most commercially successful varieties of grape in India. It is a table grape and a raisin cultivar which is widely adaptable for growing regions of India. It is mid-season and uniform in ripening. Vine is medium in vigour, the bunch is medium-large, long, conical to cylindrical, shouldered and compact. The berries are yellowish green to golden.