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== Vernacular names ==
*Grape (En). Raisin*Vigne, grappe raisin (Fr)
*Indonesia: buah anggur
*Malaysia: anggur
== Description ==
*Vigorous, climbing woody vine, 15-20 m or more tall, but in cultivation drastically restricted by pruning. Tendrils forked, produced intermittently at two out of three vegetative nodes, opposite the leaves. *Leaves simple, circular or circular-ovate in outline, 5-25 cm wide, long stalked, palmately lobed and coarsely toothed. *Inflorescences in dense thyrses that take the place of tendrils; flowers fragrant, 5-merous, actually or functionally unisexual, yellow-green, small; calyx 5-lobed; corolla with 5 petals, up to 5 mm long, joined at the tip, forming a cap (calyptra) which falls off at anthesis; disk glanduliferous and prominent. *Fruit a berry, ellipsoid to globose, 6-25 mm long, dark blue-purple, red, green or yellow, juicy, sweet or sour. *Seeds 3-4, pyriform.
== Growth and development ==
== Other botanical information ==
The genus ''Vitis'' contains about 60 species, but botanical knowledge is incomplete. All known ''Vitis'' species can be easily crossed experimentally, producing vigorous and fertile hybrids; hybridization also occurs in natural populations. Other genera like ''Muscadinia'' Small and ''Ampelocissus'' Planch. are also involved. It seems quite certain that in cultivars grown in South-East Asia, traits derived from ''Vitis labrusca'' L. and ''Vitis rotundifolia'' complement to a greater or lesser extent those contributed by ''V. vinifera'' .
''V. labrusca'' originates from the United States; it requires relatively humid conditions for good growth and is more resistant to fungus diseases. Its berries are large (15-25 mm diameter), usually blackish with a rather thick skin, and the flesh has a distinctive pungent odour and flavour. Cultivars of this species, collectively termed Labruscans, are important as producers of dessert grapes. ''V. rotundifolia'' (also named ''Muscadinia rotundifolia'' Small) originates in the south-eastern United States and in Mexico where these hardy muscadine grapes were already cultivated in the 17th Century. The species was intensively used in crosses with ''V. vinifera'' to improve the disease resistance of ''V. vinifera'' and the fruit quality of ''V. rotundifolia'' , resulting in numerous hybrid cultivars.
Cultivars which have proved successful in the tropics include "White Malaga" (fairly late, green-fruited; the leading cv. in Thailand, now being replaced by what probably is a mutant: "Long White Malaga"), "Alphonse Lavallée" (syn. "Ribier", fairly late, jet-black fruit), "Cardinal" (very early, bright red fruit), "Kyoho" (late, red-fruited; leading cv. in Japan and Taiwan), "Perlee" (green, seedless), "Isabella" (syn. "Bangalore Blue", Labruscan cv.). Cultivars in Indonesia bear local names (e.g. "Bali", "Probolinggo Biru-81", "Banjersari-45" and "Banjersari-56"), the original names having been lost.
Pruning at the beginning of each crop cycle is supplemented by pinching or cutting back the strongest shoots to allow weaker neighbours to catch up, the aim being that all shoots should be equal. This can be done when the shoots are being tied to the trellis. Where the response to pruning is unpredictable, as in the tropics, thinning of flowers and/or fruit is a valuable means of correcting the balance between growth and fruiting. Overbearing not only weakens the vine, but also affects fruit quality (less sugar accumulates in the berries). Moreover, thinning helps to produce more open clusters (less susceptible to rot) of regular shape (easier to pack). Flower thinning consists of removing the uppermost inflorescence on all or part of the shoots bearing two or more inflorescences. The bunches can be thinned shortly after fruit set to improve bunch shape, e.g. by clipping the long tip or projecting shoulder of a bunch. Individual berries are clipped if, after natural berry drop, defective or small berries remain, or if the cluster is still too compact.
Under the influence of short daylength the vine habit becomes more compact, including the bunches. Growers in Thailand dip bunches in a gibberellic acid solution (GA<sub>3</sub>, 10-50 mg/l) to force them to grow out; the treatment also increases berry size. Bunches are dipped twice: 7 days after the vineyard reaches the 80% bloom stage and 7 days later.
Vineyards are usually clean-cultivated, but growing a green manure crop, for instance during the rainy season, is recommended: the grape is partial to organic matter. Grapes can extract stored soil moisture to produce a fair crop, but irrigation gives higher yields and better crop regulation and is a common practice in the tropics. Water is very important at the critical stages of flowering and fruit set. Irrigation is stopped from a few weeks before harvest until the next pruning; this is to improve fruit quality and budbreak.
Fertilizer requirements are in the order of 150 kg N at good yield levels, 50-80 kg P<sub>2</sub>O<sub>5</sub>and 0-200 kg K<sub>2</sub>O per ha, depending on the soil. In Thailand, fertilizer is applied one month after planting and twice during each crop cycle: 7-15 days and 45 days after pruning. In the tropics manure is often applied in generous quantities when the vines have been pruned. A new vineyard may benefit from inoculation with grape mycorrhiza ( ''Glomus spp.'' ) - using soil from good maize fields - to facilitate uptake of phosphorus.
Minor nutrients may need attention. Iron chlorosis is common on calcareous soils and magnesium, zinc and boron deficiencies, as well as toxic boron levels, have been reported from tropical regions. For foliar analysis, leaf petioles are used, preferably during bloom, but recommended levels differ so much in different countries that they cannot be simply copied for South-East Asia.
== Diseases and pests ==
Diseases and pests are a major limiting factor for grape growing, in the tropics as well as elsewhere. The main fungus diseases are downy mildew ( ''Plasmopara viticola'' ), anthracnose ( ''Colletotrichum gloeosporioides'' ) and powdery mildew ( ''Oidium tuckeri'' ). During the rainy season in Thailand 2 or 3 treatments - mainly with copper and sulphur fungicides - may be applied each week. Thus, there is a real danger of copper concentrations reaching toxic levels in the soil! This intensive control programme also controls several lesser diseases.
Virus diseases undermine vigour, productivity and fruit quality of vineyards. Control of viruses - and other graft-transmissible diseases - is based on the use of certified clean planting material. As such material is not yet available in South-East Asia, it is to be expected that virus problems will eventually become an important issue.
A host of pests attacks grapes, but their occurrence is more incidental and there is no routine spray programme against leaf hoppers, flea beetles, thrips, cutworms, red spider mites, etc. If heavy cracking soils are infected with grape phylloxera ( ''Viteus vitifolii'' ), vineyards can only be successful if resistant rootstocks are used. Resistant rootstocks also solve the problem of nematodes, which spread quickly on lighter porous soils and transmit virus diseases. Constant vigilance may be required to scare off birds and bats when the fruit ripens.
== Harvesting ==
== Handling after harvest ==
The harvested bunches are placed with the bunch stems more or less upright in bamboo baskets or wooden trays lined with banana leaves or paper; containers hold 10-15 kg. Depending on the cultivar, grapes can be kept in cool storage at 1-2°C for 3-6 months at a relative humidity of 90-95%. In the tropics this may be helpful to maintain supplies through the wet season. For long-term storage the fruit is fumigated with SO<sub>2</sub>soon after harvest and at intervals during storage to reduce spoilage by decay organisms. The firm skin of most table grape cultivars allows for a surprisingly long shelf life considering the nature of the product, but utmost care in handling is important to avoid skin rupture.
== Genetic resources and breeding ==
== Literature ==
* Alleweldt, G., 1989. Weintraube [Wine grapes]. In: Rehm, S. (Editor): Spezieller Pflanzenbau in den Tropen und Subtropen. 2nd edition. Band 4. Eugen Ulmer Verlag, Stuttgart. pp. 301-310.
* Siriwachirapap, W., Tong-umpai, P., & Ketsa, S., 1985. Harvesting indices of "Cardinal" grapes. Kasetsart Journal (Nat. Sci.) 19: 167-172 (Thai).
* Weaver, R.J., 1976. Grape growing. John Wiley & Sons, New York. 371 pp.
== Authors ==
[[Category:Fruits and nuts (PROSEA)]]
[[Category:PROSEA]]