GRAPES FARMING GUIDE

 

1.0 INTRODUCTION

Grape is the most common and oldest cultivated plant in the world. It is thought to have been cultivated more than 7,000 years ago near present-day Iran.  Grapes are rich in Carbohydrates. It is rich in minerals and vitamins B6, C, E and K. They are also a source of antioxidant compounds through the phenolics in their skins and possibly seeds (Yilmaz and Toledo, 2004) . Grapes find a wide range of use such as wine production through fermentation processes, production of table grapes as raisins. Grapes are also eaten out of hand by most people in Tanzania. Some are processed into jam and jelly.

 

2.0 Origin and distribution

The exact origin of grapes is unknown, although some believe that they originated from Asia. Grapes have been distributed largely in East Asia, Europe, the Middle East and North America. The cultivars were carried to Greece, Rome and France before 600 BC. Also, the Romans spread grapes throughout Europe and they were moved to the Far East via traders from Persia and India. Spanish missionaries brought them to the US in the 1700s. In Africa are cultivated in South Africa, Egypt and Tanzania.

 

In Tanzania grapes were introduced to Dodoma by the missionaries 1960. The first small wineries were started in Bihawana and Hombolo missions. These wineries produced communal wine for church purposes only. Historically, grape production in Dodoma can be traced back to 1963 when the Isanga prison, the oldest prison started growing grapevine but, now grape is produced in Dodoma, as one of the biggest cash crops in the region. Grape production is the main stay for many farmers in Dodoma Municipal and the nearby districts of Chamwino and Kongwa. The urban Dodoma produces 70% of the grapes and rural Dodoma produces 30%. Tanzania is the most producer of grape wine in Africa which in 2016 sold more than 300,000 liters of wine ( Alko Vintage March, 2016).

Major producing countries in the World.

3.0. BOTANICAL DESCRIPTION

3.1. CLASSIFICATION

Kingdom         Plantae

Division           Magnoliphyta

Class                Magnoliospoda

Order               Rahamnales

Genus              Vitis

Specie              Vinifera

Scientific name: V. vinifera L

 

3.2. CHARACTERISTICS OF GRAPE VINE

3.2.1. The plant

·         The main aboveground structures are the trunk, head, cordons, arms, spurs, and canes.

·         The trunk branches into arms or cordons, depending on the training system. From these arise fruiting wood, 1-year-old dormant wood.

·         This wood may be retained each year as spurs, canes, or both, depending on the grapevine variety and on the cultural practices the vines may be subjected to. Spurs are short fruiting units, 1 to 4 nodes long, with 2 node spurs being the most common.

3.2.1.1. Cordons

Is a grape vine plant part which extends from the trunk and are the part where additional arms and eventually leaves and grapes clusters extend. The cordons are usually trained along wires as part of a trellis system.

3.2.1.2. Arms

Short branches from which canes and/or spurs originate, which are located in different positions depending on the system.

3.2.1.3. Canes

These are branches that support the shoots, fruit and leaves.Once the leaves fall from the vine at the beginning of the dormant season, the mature shoot is considered as a cane.

 

 

3.2.2. Leaves

·         The grape leaf consists of a blade (or lamina), the petiole, and a pair of stipules at the base of the petiole

·         Full expansion of the mature leaf blade occurs 30 to 40 days after it unfolds from the shoot tip. The upper surface contains very few stomata; it may have epicuticular hairs, and it has a well- differentiated layer of epicuticular wax consisting of overlapping platelets.

·         The lower surface lacks a wax layer but can contain epidermal hairs of various types (woolly, glandular, thorny), depending on the cultivar.

·         The lower surface has many stomata arranged in a random nature.

3.2.3. Flower

·         Grapevines have small flowers, typically 4 to 5 mm long, that are grouped together in a cluster, or inflorescence.

·         Before bloom the calyptra, a cap of fused petals, encloses the other flower parts.

·         Each calyptra detaches from its base at bloom, exposing pollen-bearing stamens and a pistil with the ovary, the enlarged basal portion.

·         If pollinated, the ovary of each flower may grow and develop into a berry.

Stages of grape flower bloom. (a) Grape flower not yet in bloom with cap attached (b) Flower in early bloom with cap dehiscing (c) Flower in complete bloom showing ovary and stamens (d) pollinator and fertilization of a gape flower

 

3.2.4.The root

·         About 60 percent of grapevine roots sit in the top 60cm of soil, but many of the plant roots grow much deeper. Grape roots can grow more 3m deep.

·         Grapevine roots are generally less dense and spread out than many other plants, but they can still spread a great distance from the main vine trunk.

·         Most of the root density is closer to the trunk, but a significant amount is sometimes more than 90cm away from the trunk. About 15 percent of root biomass is 1.175m to 1.475m from the trunk.

 

3.2.5. Berries

·         Berries are small, pulpy and often edible fruit.

·         Berries are usually juicy, rounded; brightly colour can either be black, red or white depending on variety, and sweet or sour.

·         Also berries have very small number of seed inside the fruit

 

4.0 ECOLOGICAL REQUIREMENT.

4.1 Temperature

Grapes typically require a hot, dry climate, i.e. warm days, cool nights and low humidity. Temperatures between 25 to 30oC are optimal for shoot and fruit growth. This generally produces higher-quality grapes. The hot and dry season at a particular site must be long enough to allow both the fruit and the vegetative parts of the vine to mature.

In Tanzania, Dodoma and areas near it are the best for grapevine production. Sunny days are important for the formation of sugar in the grapevine. The arid and semi-arid nature of Dodoma helps the grapevine in extending the roots. Areas with a lot of water dilute the sugar and prevent production of good grapes.

 

4.2 Water

Grapes are more drought tolerant than other fruit crop but needs regular watering. During drought plant do not sett fruit thus the amount of rainfall needed is 500-1200mm rainfall depending on climate and length of growing period. The volume of water required is determined by soil depth and soil bulk density.

 

4.3 Soil requirements

Grapevines can be grown in different soil types; they grow well in a sandy loam soil with average fertility. Regardless of soil type, the drainage must be good because this will help the roots to spread and grow well. Avoid growing grapes in soils that contain clay because it may cause poor drainage and salt accumulation. Grapes are fairly tolerant to a wide range of soils and pH, but do well in a pH of 5.5 to 6.0

 

5.0 CULTIVAR

i.                    Table grape germplasm: These are large in size as compared to other grape vine fruits. Most of the table grapes a sweet with less juice. They also contain lots of meat. They are usually not available in the market. In Tanzania, these are the most common cultivars Makutupora white, Muscat hambourg, Alphonce lavallee, Tajit Rozavij, Smederevska Muscat, Regina, Black rose, Malaga crevna, Rosso Grosso Precoce.

 

ii.                  Wine grapevine germplasm: Most grape vine fruits sold in markets are wine grapes.This is because most table grapes are scarce.These wine grapes are characterized by having high juice content and are less sweet compared to the table grapes.These grapes are mostly suitable for wine making.The wine grapes include varieties such as Queen of vine yards, Makutupora red, Chenin blanc, Syrah, Mission, Tinta cao (hybrid), Charsellas, Palomino, Murathaga, Malvazila lunga,Mollovazira bella, Ithack, Colombard, Valnack and Giem.

 

iii.                Raisins grapevines: Most raisins grapes are seedless and are white in colour.After harvest they are dried and packed ready to be sold.They can also be eaten out of hand. They are also used in cake making.The example of the variety of raisins include Ruby seedless, Beauty seedless, Halili Belyji and Kismis Creveni.

 

6.0 CULTURAL PRACTICES

6.1 Propagation

A grape is a woody vine; it can be propagated as follows;

                        i.            Cuttings

Grapevines are propagated primarily by cutting 14-18 inches long with 4-5 nodes. Cuttings can be made from dormant canes or green shoots, although in practice most are from canes. The proper time to take cuttings is when plant rest growing (dormant period). The criteria for selection of shoot for cutting are, shoot should be free from diseases and canes should be at dormant stage because softwood is more susceptible to disease than dormant cane cuttings. In sandy soils, short cuttings do not grow as well as long cuttings. In addition, cuttings can be held in refrigeration but should be removed about two weeks before planting and allowed to warm and start growing.

 

                      ii.            Seeds

Grapevines can be propagated by seeds but the use of seeds for propagation is not satisfactory because the seedling does not resemble the parent’s vines. Seeds take long time to come into bearing therefore not preferred.

                    iii.            Rootling

These are vine materials that develop roots and includes original and grafted.

                    iv.            Tissue culture

Grapes can also be propagated using tissue culture. This method is not widely utilize

 

6.2 Weeding:

It is very important to keep the vineyard (grape farm) free from weeds in order to avoid competition for nutrients, water and light. Normally three weeding operations are sufficient for keeping the field free of weeds, depending on weed intensity of the site.

 

6.3 Irrigation:

Irrigation of table grapes should be regulated so that the growth rate of berries is kept moderately and uninterrupted. Excessive irrigation is likely to give large watery berries lacking flavour such fruit does not pack, travel long, keep or eat well. Therefore different soil types require different levels and frequencies of irrigation i.e. light sandy soils need less water but more frequently compared with heavier clay soils.

 

6.4 Planting

Row orientation: Row orientation is mostly influenced by the direction of the prevailing winds and solar aspects.

 

6.5 Spacing. The usual spacing between the vine rows could be from 3.0 – 3.7m which could provide ample space for vine growth. Spacing within the row is generally wider for table grapes than wine grapes i.e. vine spacing of 2-2.7m are common for vigorous varieties.

 

6.6 Trellising and support poles. Grape is a crowing plant, it needs supports from young age to mature plant so as to grow upright. The support poles may be of iron or treated woods. The poles help to hold the plant upright in order to allow other activities such as weeding, chemical spraying and harvesting to be carried on smoothly.

 

6.7 Types of trellising in Grape vine production

Trellising is the art of arranging the vine in space.

 

6.7.1 Self- or stake-supported

The simplest training systems are staked vines or bush vines. The vine is trained to a short trunk tied to a stake on which a head with several short canes is left. Once the trunk can support the weight of the canopy and fruit on its own, the stake can be removed.

 

 

6.7.2 Single wire

Single wire trellising systems are used for a variety of purposes and are low cost relative to most other systems, due to only one wire being needed. Here, a single fruiting wire is used and shoots arising from the cane or spurs are free to grow in whichever direction they end up.

 

6.7.3 Hedge-type

Vertical Shoot Positioning is a widely used trellising system for the production of wine grapes and results in the box-shaped hedge that is seen in so many vineyard calendars. A fruiting wire is relatively close to the ground (typically 90 cm at a row spacing of 2.5_3.0 m), dormant canes wrapped to it (the horizontal cane version of this is called a Guyot system) and shoots are trained upwards from it during the growing season. This results in a fruiting zone above the cane, which localizes the crop relative to most of the canopy. Fruiting wires can number one or two, with one to four fruiting canes being typical.

 

6.7.4 Divided canopies

Divided canopies were developed to address the concerns of maximizing crop and accommodating high vigor. The first significant breakthrough in this area was made by Nelson Shaulis and his research crew of the Geneva Experiment Station in New York, USA (Shaulis et al., 1967). The Geneva Double Curtain addressed the issues of increasing productivity (through better light interception per unit land area) and mechanization of ‘Concord’ grapes, which were primarily grown for juice production. The system is effectively two single wire systems set side by side. Due to the trailing growth habit of V. labrusca vines, two distinct curtains of shoots develop (though usually with the help of some shoot positioning). GDC has been adapted for use with other grapevine species, though its best application remains with trailing growth-habit cultivars.

 

 

7.0 Pruning.

Pruning is the art of cutting old and weak/affected branches or cane in order to rejuvenate the plant. Pruning is done so as to have a reasonable shape of the plant which will enable other activities to be carried out in the field; such as weeding, irrigation and spraying of chemicals, to reduce unnecessary branches in order to maintain healthier plants, to initiate flowering, to monitor grape production, obtaining grape with good quality, to allow the plant rejuvenate new fresh branches which bears fruits for next season, to remove old (dormant buds), weak and affected branches.

 

There are two main types of pruning that can occur: summer and winter.

The purpose of summer pruning (removal of green shoot parts during the growing season) is mainly to open up the canopy, prevent self-shading or just to tidy up the appearance of the vines.

The real work in pruning happens in the dormant season, when a decision has to be made as to how much, and which parts, of the previous season’s growth must be removed. The aims of pruning are to:

● Establish/maintain the vine in the desired form.

● Produce fruit of the target composition.

● Select nodes that will produce fruitful shoots.

● Regulate shoot number/crop load.

● Regulate vegetative growth.

 

7.1. TYPES OF PRUNING

The principal methods of pruning are cane and spur (also known as cordon pruning).

 

7.1.1. Cane pruning.

With cane pruning, the fruiting shoots for the next season come from a length of the previous season’s shoot, which is laid down and wrapped on the fruiting wire of the trellising system. Cane pruning typically uses up to four canes of 8 to 15 nodes in length on the vine, depending on trellis, vine spacing and cropping aims. In most cases, one or two replacement spurs are also left below the head, which is to facilitate cane choice the following year.

 

The goal is to choose canes that are

(i)                 In a good location to retain the shape of the vine;

(ii)               Well-exposed in the previous season, to give maximum fruitfulness;

(iii)             Have good periderm formation; and

(iv)             Not excessively thick or thin. The latter two parameters are associated with the cane’s ability to withstand cold while dormant and increased fruitfulness in the following growing season.

 

Advantages of cane pruning are

·         That vine fruitfulness is maximized

·         The number of potential non-count nodes on the vine is minimized, because there is less permanent wood on the vine and therefore less surface area from which latent buds can arise. As some cultivars are inherently less fruitful at the basal node positions on the shoot, cane pruning minimizes the relative impact of this.

 

Disadvantages of cane pruning include

·         Blind budding (places along the cane where no shoot develops), especially with long canes;

·         Limitations to between-vine spacing (in that the distance between vines is restricted to no more than twice the length of a typical shoot during the growing season); and

·         Un even shoots growth along the cane.

 

The latter phenomenon has been called the End Point Principle by David Jackson (1997), where shoots at the end of a cane tend to grow more vigorously than those in the mid-portion of the cane. Extreme examples of this arise when there is no shoot development in the middle parts of the canes, but there is at the ends and bases, which also demonstrates the Trunk Proximity Principle, where Shoots tend to develop more vigorously near the base of the canes. Cane pruning can also be more difficult when training workers to make the best decisions, resulting in loss of some of the advantages of cane pruning in the first place.

 

7.1.2. Spur pruning

Spur pruning does away with continued use of canes by establishing a permanent arm, or cordon, from a cane. Note that,  in establishing a cordon, shoots arising from the downward-facing bud on the original cane are removed, leaving every alternate and upper node positions present.  Downward-pointing shoots do not grow so vigorously and, if shoots from both nodes were used, it would enlarge the fruiting zone, making some management practices more difficult. To counteract the loss of shoots from these positions, canes arising from the remaining nodes are cut back to (typically) two-node spurs. Note that, when training a cane that is destined to become a cordon, it should not be wrapped as tightly as if the vine is cane pruned every year. Too many revolutions around the wire can result in girdling of the cordon as it increases in girth.

 

Advantages of spur pruning are that

·         It is easier to teach unskilled people how to do it.

·         It is possible to partly mechanize the process using cutting bars which means that the crew that goes in afterwards has much less brush-pulling to do.

·         Spur pruning also results in the vine having more permanent vine material, which has been implicated in fruit quality.

 

Disadvantages are

·         Vine fruitfulness is limited (because the basal nodes on canes are typically not as fruitful);

·         Spurs can die out over time due to injury, disease or other problems;

·         The fruiting zone can creep upwards through the seasons if there is a tendency for pruners to choose the distal nodes on each of the spurs (this can result in very uneven or high fruiting zones); and

·         The cordon needs to be renewed periodically due to damage, disease, etc.

Other factors to be aware of in spur pruning relate to the canes that were used to set up the cordons. Spur spacing depends on the internode length of the original cane, so initial cane choice is important. If internodes are too long, then spurs will be spaced too far apart and cropping will be limited. If they are too close together, there will be shoot shading, dense canopies and a host of other problems that are related. For most situations, keeping replacement spurs near the head of the vine is vital; because it is from those that renewal canes/cordons can be sourced. To avoid the upwardly creeping fruiting zone, pruners must be aware that shoots from the lower of the two nodes need to have preference over the upper. The low potential fruitfulness of spur-pruned

Vines can be overcome somewhat by altering the length of spurs retained, though this does have significant effects on the resulting canopy unless remedial measures (such as shoot thinning and leaf removal) are taken during the growing season. No matter what the pruning system, there remain some tips to smooth the pruning process. If movable foliage wires are used in the trellising system, be sure to move these down before budburst as then they will catch the shoots as they are raised. If any trellis posts or wires have broken, your only chance to fix them is at pruning, before any tying down of canes has to take place.

 

Other considerations when pruning

1.      Prune as late as possible: bud break is delayed by late pruning, which can be an advantage if the vineyard or block is located in a frost-prone area. Yields have also been shown to increase with later pruning dates, which also may be an advantage. Delayed pruning and removal of pruned wood must be done carefully if the buds are swelling _ they can be brushed off easily.

2.      Choose canes that were in well-exposed positions: flower cluster initiation takes place in the buds at the base of each leaf near bloom, meaning that the following year’s crop is beginning to be determined almost 18 months before it is actually harvested. When pruning and laying down canes, pick those that have been well exposed during the early part of the growing season.

3.      Plan ahead for canopy density: overlapping canes will cause excessively dense canopies, which will lead to poor flower cluster initiation, spray penetration, air movement and fruit ripening. If more nodes need to be left than space available on the wire then, if possible, add another fruiting wire, arch the canes or perhaps the vines are too vigorous for the trellising system, in which case it should be changed.

4.      When is big too big? If single-canopy vines are producing near or over 1 kg of pruning per 1 m of row, it may be worthwhile considering changing to a divided canopy. The ideal values for pruning weights in these systems fall between 0.3 and 0.6 kg/m of row. If, for example, vertical shoot-positioned (VSP) trained vines are producing much over that, conversion to a divided canopy of some sort should result in more moderate growth over a larger area. This will return better-quality fruit (due to more fruit exposure to the sun, better airflow and better spray penetration), increased yields per acre and fewer management interventions, which should offset the cost of the Conversion. If vigor is still a problem then other management techniques must be used to reduce it, for example, through the use of more aggressive cover crops, reduced irrigation, etc.In general, if there is excessive shading in the canopy resulting in disease (because of poor spray penetration or increased humidity due to lack of air movement), poor fruit quality from lack of exposure and poor fruitfulness of the buds (due to a lack of light for flower cluster initiation), some management intervention is needed to correct it.

 

8.0 HARVESTING

The timing of harvest has perhaps the most impact on grape composition. Therefore, knowing what the grapes are going to be used for is vital in determining when and how to harvest. For example, early harvest of wine grapes means that flavour, sugar and acid profiles are substantially different, and suited to styles such as sparkling wines or verjus (unfermented juice of unripe grapes, used in cooking). Late harvesting of grapes can result in raisins or those suited to producing dessert wines, which have high residual sugar. The products can be very distinct, but in some cases come from the same cultivar. Harvesting method is also of importance to product quality. For fresh consumption, delicate handling is required for premium fruit, as the bloom (waxy covering) of the grape should be preserved.

 

Fruit are hand harvested and placed in protective containers for shipping to market. For some wine styles, hand harvesting is a must; for example, for sparkling wine production the fruit needs to be intact before processing starts or harsh phenolics may be extracted from the rachis and skins. For many table wines, however, machine harvesting is acceptable as the breaking of the berry skins and their mingling with the juices helps to extract desired compounds.

 

8.1 Table grapes

Indexes used for harvest

The quality of table grapes depends on sugar concentration, acidity, colour, texture and aroma and flavor characteristics of the variety. Though sugar concentration is a common quality measure for grapes, there is not always a good relationship between it and the palatability of grapes for fresh consumption. The ratio of berry juice Brix to acidity can give a better measurement of the palatability of grapes to consumers than either the sugar content or acidity used alone, although the best measure of quality varies between cultivars.

 

Picking

Table grapes are all picked by hand. Pickers must be trained to select well shaped clusters of mature grapes. Because not all clusters will be suitable for harvest at the same time, frequently there must be multiple harvests from each vineyard .Though berries can be tasted to determine

suitability for picking, this cannot be done for every cluster so visual cues, such as berry size and color and rachis color, must be used to determine whether the cluster meets the picking criteria.

 

 

 

8.2 Raisins (Dried grapes)

Indexes used for harvest

Harvest criteria for raisins revolve around improving the final yield of dried fruit, of which sugar concentration in the fresh fruit is a major component. As the concentration of sugar in the grapes rises, so does the yield of finished raisins, according to the drying ratio, which is the mass of fresh grapes it takes to produce 1 kg of raisins at 15% moisture. Because gross returns are based on the amount of raisins produced, starting with higher-Brix fruit provides more money per tonne of fresh grapes. Raisin quality also improves with increasing Brix,though achieving higher sugars carries with it a greater risk of rainfall late in the season.

 

8.3 Wine grape

Indexes used for harvest

Grape maturity for wines depends on the wine being produced. Grapes for sparkling wine production, for example, are harvested at a lower Brix than those for still table wines, and grapes for late-harvest wines are picked when the sugar levels are higher than for table wines. Grapes for most wines, however, require sufficient acid and sugar to result in the desired pH, alcohol content and flavor, and also acceptable varietal aroma, to produce a quality wine.

 

9.0 POST HARVEST HANDLING

9.1 Pre-cooling

The pre-cooling is practiced to reduce field heat. Prompt removal of field heat from harvested berries is the best way of retaining the freshness of grapes for a longer time. The temperature in the pack house should be maintained at 18-20°C and the grapes should be transported to pre-cooling units within 4-6 hours of harvest.

 

9.2 Cold storage

After pre-cooling, the dual releasing sulphur dioxide pads (Grape guard) are placed with their coated surfaces facing downwards on the filled plastic pouches and covered with the plastic sheet lining. The boxes are closed and shifted to cold storage rooms where the temperature and humidity are maintained at 0 ± 0.50C and 93 ± 2% respectively. Temperature of 0°C and humidity of 95% are the best for maintaining freshness and preventing decay. Freezing injury to berries, pedicels and rachis occur at –2°C, while at slightly higher temperatures decay may occur. Care should be taken to maintain the temperature and humidity strictly during storage and transit.

 

10.0 PEST AND DISEASE

10.1 Diseases

Disease in grapevines can be caused by a wide range of organisms, including those of fungal, bacterial and viral origin.

10.1.1 Fungal diseases

The most common fungal diseases are Botrytis (bunch rot), Powdery mildew, Downy mildew, And Phomopsis.

10.1.2 Bacterial Diseases

There are two major bacterial diseases in grape vines. These are Crown gall and Pierce’s disease

10.1.3 Viral Diseases

Grapevine fan leaf virus (GFLV, or fan leaf degeneration) and Grapevine leaf roll

10.2 Pests

10.2.1. Foliage Pests

Ø  Grape phylloxera, Daktulosphaira vitifoliae (Hemiptera: Phylloxeridae), it affects the appearance of the leaves without impacting the health of the grape. Severe infestations of foliar phylloxera can reduce the photosynthetic ability of grape leaves.

Ø  Japanese beetle, Popillia japonica (Coleoptera: Scarabaeidae), Japanese beetle adults are leaf skeletonizers, i.e. they eat the leaf tissue between the veins, giving the leaf a lace-like appearance.

10.2.2. Flower and fruit pests

Ø  Grape flea beetles, Alticaspp. (Coleoptera: Chrysomelidae). Adult beetles damage primary buds when they feed on them, which prevents them from developing into shoots, which results in decreased grape yield.

Ø  Grape Berry Moth, the larva is the damaging stage of the insect, and causes damage by feeding on the grape berry. In addition, larvae can be a contaminant or act as an entry point for diseases.

Ø  Multicolored Asian Lady Beetle, once grapes are damaged, adult beetles feed on the injured areas of the berries. In addition, adult beetles are a contaminant in wine production.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

REFERENCES

Coombe, B.G 1992. Research on development and ripening of the grape berry. American journal of enology and viticulture 43:102-110

Kalimang, N and  Majula,R (2014), International Journal of Scientific and Research Publications,  The Economic Analysis of the Smallholders Grape Production and Marketing in Dodoma Municipal: A case study of Hombolo Ward, Volume 4, Issue 10, October 2014 1 ISSN 2250-3153 www.ijsrp.org.

Lakso, A.N., Pratt, C., Pearson, R.C., Pool, R.M., Seem, R.C. and Welser, M. J., 1982. Photosynthesis, transpiration, and water use efficiency of mature grape leaves infected with Uncinula necator (powdery mildew). Phytopathology 72, 232–236.

Loinger, C., Cohen, S., Dror, N. and Berlinger, M.J., 1977.  Effect of grape cluster rot on wine quality. American Journal of Enology and Viticulture 28(4), 196–199.

Mullins, M.G., Bouquet and L.E Williams. 1992 Biology of the grapevine Cambridge university press, university

Nair,  N.G. and Allen, R. N., 1993. Infection of grape flowers and berries by Botrytis cinerea as a function of time and temperature. Mycological Research 97, 1012–1014

Reisch, Bruce; Stewart, Philip, 2001.“Grape Breeding Procedures”. Cornell Grape Breeding. Retrieved 16 November 2015.

Richard D. 1983. The grape root system. Horticulture reviews 5:127-168

Shaulis, N.J., Shepardson, E.S. and Jordan, T.D. (1967) The Geneva Double Curtain for Vigorous Grapevines: Vine Training and Trellis Construction. New York StateAgricultural Experiment Station, Geneva, New York, 12 pp.

 

Todd Rosenstock of the International Programs Office, 2007.  POSTHARVEST TECHNOLOGY and METHODS for Grapes and Raisins University of California,  Davis.

Vaden, D. H. and Wolf, T. K., 1994. The cost of growing wine grapes in Virginia. Virginia Cooperative Extension Publication 463-006