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Beutel, J.A. 1990. Kiwifruit. p. 309-316. In: J. Janick and J.E. Simon (eds.), Advances in new crops. Timber Press, Portland, OR.

Kiwifruit

James A. Beutel


  1. INTRODUCTION
  2. CLIMATE AND PRODUCTION AREAS
  3. ECONOMICS
  4. CULTURAL PRACTICES
    1. Soil and Water Needs
    2. Planting Stock
    3. Irrigation
    4. Wind and Windbreaks
    5. Frost Problems
    6. Pests, Diseases and Chemicals
    7. Fertilizer
    8. Pruning
    9. Harvest and Storage
  5. NEW CROP TO SURPLUS CROP
  6. REFERENCES
  7. Table 1

INTRODUCTION

Kiwifruit are produced by a large, deciduous vine botanically known as Actinidia deliciosa. Individual plants bear either staminate or pistillate flowers, so both types of plants are planted in a vineyard at a ratio of 8 pistillate to 1 staminate to insure adequate cross-pollination and fruit set. Bees are necessary for pollination; wind pollination is unsatisfactory because it does not produce large fruit. Worldwide 'Hayward' is the preferred cultivar because of its large fruit. There are many staminate cultivars; 'California' or 'Chico' is the most common in California and 'Matua' is widely used in California and New Zealand.

The vine is native to China where it is called yangtao. The first commercial kiwifruit vineyard was planted in New Zealand about 1940 and more acreage was planted in the 1950s in the Bay of Plenty district near the city of Tauranga. Now kiwifruit are grown in many districts on the north island of New Zealand and in the Nelson area on the south island. Fruit was exported from New Zealand to the United States as early as 1958 and was featured first as Chinese gooseberries and later as kiwifruit. By 1981, New Zealand production had increased to 6.5 million trays (7.5 lb.) which were exported to the United States, Europe, and Asia. Four years later, New Zealand exports were 26 million flats; in 1987 and 1988, New Zealand exported 40 to 48 million trays. Bearing and nonbearing plantings in New Zealand in 1986 totaled more than 50,000 acres (20,000 ha).

The kiwifruit is a relatively new crop in California. The first plantings were made in 1967, and by 1971 at least 100 acres had been planted in California, most of it in Butte and Kern Counties. The original experimental vines were grown at the USDA Plant Introduction Station at Chico as early as 1934. The mother 'Hayward' vine and father 'California' staminate vine, still growing and producing at this original location, are the source of most California kiwifruit plants. The first significant commercial crop of 300,000 seven-pound trays of kiwifruit was packed in 1977. In 1982 and 1983, 3.2 million trays (11,000 tons) were packed in California. In 1985 and 1986, 5.0-5.5 million trays (18,000-19,000 tons), and during 1987 and 1988, approximately 8 million trays, were packed in California. During the 1980s, about half of the packed California kiwifruit has been exported to Japan and Western Europe and the rest of it has been sold in the United States and Canada. There were over 8,000 acres (3200 ha) in California and in 1988, with 25% in early bearing stage and 75% near full bearing (over 6 years old).

Grower returns in the 1970s were about $1.00 per pound of packed fruit. In 1986 and 1987, returns were 30 to 40 cents per pound of packed fruit. Costs to grow, harvest and pay interest on investment is close to 30 cents per pound at average yield of 8000 pounds of packed fruit per acre.

The fruit is about the size of a hen's egg and has a fuzzy brown skin which covers attractive, emerald green flesh filled with small, black, edible seeds. In the United States and worldwide, kiwifruit are sold primarily as fresh fruit. No processing method that uses significant quantities of fruit has so far been found to be profitable. Some fruit are processed into jam, others into juice or wine, and some have been frozen, but all processing outlets combined use only a few tons of fruits. Thus, production of large-sized, quality fresh fruit is essential for success in kiwifruit growing. For best flavor, fresh kiwifruit should be allowed to soften like avocados and 'Bartlett' pears. Hard kiwifruit are very acid in taste and not palatable. Freshly picked kiwifruit will soften and be ready to eat in a few days if put in a plastic bag with apples or bananas and stored in a warm room (68-70°F). Kiwifruit stored in a refrigerator for 4 or more weeks will soften without apples if taken out and left at temperatures over 60°F. The fruit is high in vitamin C (100 mg per large fruit) and potassium (340 mg per large fruit) and contains 50-60 calories.

Kiwifruit in California can be stored for 4-6 months, sometimes longer in New Zealand. New Zealand picks fruit in May and June and sells stored fruit worldwide through December. California sells kiwifruit November through April. Thus, in major markets of the world, good fresh kiwifruit are available year-round. More consumer education and kiwifruit promotion are needed in the United States and these are provided by the California Kiwifruit Commission established in 1981 with headquarters at 1540 River Park Drive, Suite 120, Sacramento, CA 95815. The New Zealand Kiwifruit Authority does promotion on a worldwide basis. The market for fresh kiwifruit should expand as the avocado market has over the last 20 years. Per capita consumption is about 0.25 lb in the United States and over 1.0 lb in Japan and West Germany.

CLIMATE AND PRODUCTION AREAS

Acceptable climates for 'Hayward' kiwifruit must have winter temperatures below 45°F (7-C) for 600-700 hours. A frost-free season of 225-240 days is needed for kiwifruit since vines leaf out in March, bloom in May, and are harvested in October or early November. Temperatures below 10°F (-12°C) in mid-winter will kill all young vines and some old bearing vines. Frost below 30°F (-1.0°C) in spring will kill shoots and ruin the crop. In mid-November, frosts below 27°F (-2.5°C) can damage trunks of young vines. Well-spaced overhead sprinklers can provide protection up to 6°F if they apply 50 gallons of water per minute (or 3,000 gallons per hour) per acre and are turned on before freezing temperatures occur. Hail in the spring can break shoots and reduce the crop severely. Cold hardy kiwifruit species (A. arguta and A. kolomikta) with very small fruit can be grown in cold climates like the eastern U.S. and they will tolerate about -10°F (-24°C).

Kiwifruit vines need frequent irrigation or rainfall to grow well so they can be grown in areas of heavy summer rainfall or hot dry summer areas when given irrigation. Kiwifruit grow well in hot summer areas with maximum temperatures up to 114°F (45°C) if adequate (8,000-10,000 gallons per acre) water is provided daily for the plants. Where 90°F maximum temperatures occur about 6,000 gallons of water per day per acre are adequate. Soils must have reasonable drainage, contain minimum salts, not be too alkaline (less than pH 7.3), and be deep enough to grow a good peach orchard.

In California, kiwifruit can be grown in most areas of the Sacramento and San Joaquin Valleys where peaches and fruit are grown. They cannot tolerate severe winds or poorly drained or alkaline soils. Major commercial kiwifruit districts in the Central Valley are Chico, Gridley, Yuba City-Marysville, Modesto-Livingston, Madera, Fresno, Reedley-Dinuba, Visalia-Exeter, Porterville, and Delano-McFarland. Other kiwifruit districts are in the central coast region (San Luis Obispo, Watsonville-Santa Cruz); intermediate valleys such as Gilroy, Fairfield-Winters, Sebastopol-Healdsburg; foothill districts below 1,500 feet elevation and with minimum frost such as Lincoln and Loomis; and some areas in Southern California with above average winter chilling without severe frosts (below 24°F). Kiwifruit are grown to a limited extent in other areas of California not specifically mentioned.

In Southern California, warm days (70°F) or lack of winter cold in December and January reduces yield many years. In foothill and north coast areas, frost limits production. Wind in many areas scars the fruit and breaks the growing and fruiting canes and so delays plant growth and reduces production. Poplar or Casurina windbreaks can reduce wind problems. In the Sacramento Valley, years of heavy spring rainfall have killed kiwifruit vineyards on poorly drained soils. Nematodes and water problems have limited plant growth in sandy soils in the San Joaquin Valley.

In addition to California and New Zealand, kiwifruit are also grown in Italy, Japan, France, Chile, China, Spain, Greece and Israel. Italy has over 12,000 acres (4800 ha), Japan and France each have about 6,000 acres (2400 ha) of bearing and nonbearing vines, and other countries have 100 to 1,000 acres (40 to 400 ha) each. In the United States some small acreages exist in Oregon, South Carolina, Florida, Texas, and Louisiana but winter cold caused severe damage to these plantings in 1981, 1983 and 1985.

ECONOMICS

Production of kiwifruit is expensive since a high capital investment is required for vines, trellises, and a permanent sprinkler or drip irrigation system. It takes 4 years after planting to produce a commercial crop. Vines are commonly planted 15-18 feet apart in rows 15 feet apart, resulting in 160-190 plants per acre. The current price for most grafted plants is $7.00-$9.00 each. For support, vines must be trained on a sturdy trellis system consisting of 4-5 inch diameter poles 9 feet long with 2 inch x 6 inch x 6 feet crossarms. This T-shaped trellis (called a T-bar) with wires, end posts, and anchors costs about $2,000 per acre installed. Many California growers now train kiwi vines on a solid overhead trellis called a pergola or arbor. Costs of materials and installation for a pergola is $2,500 to $3,000 per acre. Other popular trellis systems are 2 or 4 row arbors with driveways every 2 or 4 rows and the [[Pi]] system where an 8-foot cross arm is supported by two posts per vine. They cost $2,000-$2,500 per acre installed.

Young and old kiwifruit vines require frequent irrigation every 2-3 days for the best growth. This mean sa solid set, permanent irrigation system is required. It may be a drip, minisprinkler or undervine sprinkler system. Costs for drip or minisprinkler systems installed are about $1,000 per acre including filters but not the cost of the well and pump. Costs for solid set under or overvine impact sprinkler systems are about $2,000 per acre plus cost of well and pump. Growers in the Sacramento Valley or foothills use an overhead sprinkler system for frost protection and to maintain a cover crop and use a drip or minisprinkler system to provide frequent vine irrigation. These dual systems double the cost for irrigation systems. Generally, it is undesirable to irrigate over the vines during the summer since water causes stains on the fruit. Many California water sources are high in calcium and bicarbonate and when irrigation water is applied during the day over the vines, white "hard water" deposits develop on the fruit which ruin their appearance. Thus, under-vine irrigation during the day or over the-vine night application is necessary. Methods of converting over-the-vine frost systems to under-vine sprinklers are available, or overhead sprinklers are used for frost protection and under-vine drip or minisprinklers are used for summer irrigation.

Total costs to train and give cultural care to a new kiwifruit vineyard for the first 4 years are $2,500-$3,000 per acre. Weed control, training and pruning, irrigation, fertilizing, and windbreak planting make up the major costs. Costs in 1986 for good orchard land that can be used for kiwifruit range from $3,000-$5,000 per acre, but have been as high as $6,000-10,000 in 1979-80. If the soil is fumigated for nematodes prior to planting, this add $400-$600 per acre. Prior to fumigation, land leveling and ripping is desirable and may cost $500 or more per acre.

Briefly summarized, the costs per acre of establishing a kiwifruit vineyard (over a 4 year period) are as follows:

Land preparation (level, rip, fumigate) $1,000
Plants, stakes and planting (160 vines/acre) $1,800
Trellis materials, anchors, posts, wire and installation $2,000-4,000
Sprinkler systems installed $1,000-2,000
Care and training vines for 4 years $2,500-3,000
Total $8,300-11,800

To the above total add the price of a tractor, mower, sprayer, forklift, pickup, well and pumps, tools, interest costs, and maybe a packinghouse. The actual costs of these vary with each grower.

Production and income "ill vary with choice of vineyard site, packout and grade of fruit, future prices for fruit, management ability, and success of venture. Approximate yields are listed below that may be expected with good management and a good growing site. This is about twice that of the average California planting. Higher and lower yields by individual growers can easily be found. The average output of all bearing California vineyards is about 1,000 packed trays per acre. Most vines are expected to be productive until the age of 20 years with yields under favorable conditions of 9.5 tons or 2,000 packed flats per acre. Approximate returns to the grower after packing, cold storage, assessment and selling charges have been withheld are shown in Table 1. As an example, if fruit sells for $7.00 per tray of 7.5 lbs at the packinghouse, the grower would receive $3.00 if packing, storage, selling charges etc. were $4.00 per flat. If selling price is $6.00 and costs are $3.80, then the grower would receive $2.20.

Annually it costs (for labor and materials only) $1,500-$2,000 per acre to grow and harvest kiwifruit. If these costs are subtracted from the above listed returns, it will take 9-10 years at $3.00/tray just to recover establishment costs exclusive of land and interest costs. Should the lower returns of only $2.20/tray exist, it will take 12 or more years to recover development costs. At the state average yield of 1,000 packed trays per acre, the grower can never pay off the investment since his returns will only cover his production costs. High yields over 2,000 trays per acre are the only answer for profits. Long-term prices for kiwifruit are hard to project but growers should be able to receive after picking and selling costs somewhere between $2.00 and $3.00 per tray most years in the 1990s.

One also must consider possible delays in plant growth, crop losses from frost or wind, variable yields due to nature and management, and packinghouse and storage problems, which can reduce yields and sales of packed fruit and add unexpected costs or losses. Despite these problems, it still appears that kiwifruit in good production areas can be profitable assuming normal economic conditions and providing the grower or investor has adequate capital and can provide good management and wait for full production.

Cultural and harvest costs for full-bearing kiwifruit vineyards have been $1,500-$2,000 per acre annually Pruning and harvest costs together are 50%-60% of the annual costs. Interest on investment is another high cost that varies with each grower and has not been added to the costs shown.

CULTURAL PRACTICES

Soil and Water Needs

Kiwifruit vines grow best on class 1 soils, especially deep, alluvial soils. Good and sometimes excellent production is obtained on class 2 soils if properly managed. Kiwifruit vines grow and produce better on loam and silt-loam soils than on loamy sands.

Kiwifruit vines require low-salt water as other fruit crops do. Chloride, bicarbonate, boron, and sodium are the most damaging. Approximate safe levels for irrigation water are: chloride less than 70 ppm, bicarbonate less than 200 ppm, boron less than 0.25 ppm, sodium less than 50 ppm, and electrical conductivity EC x 103 less than 0.75. Soil for kiwifruit vineyards should have less than 0.25 ppm boron, low sodium, electrical conductivity of 0.75 or less, and pH less than 7.3.

Planting Stock

Getting good bare root or container plants is essential for a good start, and ordering should be done a year or two ahead of planting. The larger plants are preferred. Plants should be 3-6 feet high with a diameter near the bud union of about 1/2 inch. More plants are lost in the first year when smaller plants are used and smaller plants take longer after planing before they produce fruit. Most plants are grafted on 'Hayward' or 'Bruno' seedling rootstock and rooted cuttings of 1/2 inch diameter make good plants.

'Hayward' is the only acceptable commercial cultivar. Any good pollinizer that blooms at the same time as 'Hayward' is satisfactory. The 'California' staminate clone is the most widely used pollinizer in California. Plant an outside row of all pistillate 'Hayward' plants. Follow that with a row consisting of one staminate plant between every two pistillate plants, then 2 rows of all pistillate plants, another row with one staminate between every two pistillate plants, 2 more rows of all pistillate, etc. This means that every third plant in every third row should be staminate vine.

Irrigation

Irrigation is extremely important for optimum plant growth and good production. Irrigating daily or every two days in the summer is usually advisable for the first 3 years after planting, and three to four times per week for bearing plants. Excessive irrigation or poor drainage can cause crown rot, yellow vines, and plant death. Under-irrigation reduces growth, causes some sunburned leaves, produces small fruit, and stunts plant growth. Severely deficient irrigation causes leaf burn and will ultimately result in plant death. Kiwifruit vines need more irrigation than grapes or fruit trees under similar soil and weather conditions.

Three different irrigation systems are used for kiwifruit vineyards. Drip irrigation saves water and is commonly used on most young plantings. At the time of planting and for the first year, one emitter is placed near each plant. The second year one emitter is put on each side of the plant about 12-18 inches away from the plant. When the plant is 4 years old, two more emitters are added 3 feet away from the first emitters. Drip systems can supply water to vines every day or every 2 days which usually results in rapid growth. When plants reach full bearing, it is difficult to wet enough soil with 4 emitters per vine to get maximum yield and plant growth. At that time many growers shift to minisprinklers for irrigation or add more emitters per vine.

Minisprinklers are small plastic sprinklers that throw a fine spray of water through a fixed or rotating head depending on the make. Minisprinklers will spray water in a circular pattern 6-18 feet in diameter. Full circle and partial circular patterns are available. Each minisprinkler is set on a plastic stake, placed in the soil under the vine, and attached to the lateral plastic water line with small spaghetti-shaped tubing. Minisprinklers may be hung on a small plastic tube connected to a lateral line attached to the trellis system instead of being placed on a stake set in the soil. Generally minisprinklers wet a circular area between plants and are allowed to run 6,8, or 12 hours two to four times per week. They wet more soil than the drip system does, are easy to install, can be used to replace drip, and plug less frequently than do drip emitters.

The third system widely used in older kiwifruit vineyards is an impact sprinkler. These traditional sprinklers can be placed over or under vines. Overhead irrigation systems are good for frost protection but do cause some spotting or discoloration of the fruit when used for irrigation during the summer. To avoid this, many growers are changing overhead sprinklers to undervine sprinklers by putting a T assembly on the plastic sprinkler riser and transferring the sprinkler to this during the irrigation season. The upper sprinkler adapter is plugged in the summer. When frost season arrives in the fall, the sprinkler is transferred back to an overhead position and the T assembly is plugged. These sprinkler systems can work fine if no vine interference occurs. They tend to use more water than the other systems but also have fewer plugging problems.

Wind and Windbreaks

Only areas with minimum wind should be used for growing kiwifruit because wind easily breaks canes, damages fruit, and reduces plant growth. Both daily coastal breezes of 5-15 miles per hour and hard spring and fall winds of 15-50 miles per hour break canes and reduce growth and production. Every cane broken by the wind means 4 to 6 less fruit per vine.

Use of windbreaks will provide partial to adequate protection depending on the type of tree used and the severity of the winds. Poplars and certain willows are generally considered the fastest growing windbreaks, although some growers find certain kinds of casuarina, pine and eucalyptus acceptable. A windbreak protects 200-250 feet downwind so windbreaks are best placed every 200 feet through a kiwifruit vineyard. Roots of windbreak trees do compete with vines so windbreaks should be irrigated frequently and kiwifruit vines spaced at least 20 feet from windbreak treas. Many areas in California have infrequent wind conditions so growers do not use windbreaks. New Zealand needs more wind shelters than California.

Frost Problems

Frost damage to young vines in the fall and spring can result in plant death or killing of the budded portion of the vine. Temperatures below 30°F (-1°C) in the spring will damage new leaves, fruit and tender shoots. In November, temperatures below 27°F (-2.5°C) may cause trunk damage to young vines and will freeze leaves. After 2-4 nights of freezing temperatures (with or without frost protection), vines usually tolerate temperatures in the mid- to low 20s F (-4 to -5°C). Cold sites, generally, are not satisfactory for kiwifruit vines, although some growers are able to grow vines in these areas but often take plant losses due to the cold. Maximum temperatures that mature, winter-hardy 'Hayward' kiwifruit vines will safely tolerate appear to be about 10-15°F (-9 to -12°C). In Europe in January of 1985, some kiwifruit vines survived -18°C, but many were killed to the ground. Sprinklers can help protect vines against cold damage, but protection is limited to 6-8°F (3-4°C) of frost when overhead sprinklers apply 50 or more gallons of water per minute (or 3,000 gallons per hour) per acre. Under-vine sprinklers and misters give only 2-3°F frost protection. Sprinklers must be started when temperatures are several degrees above the critical temperature to perform as described.

Pests, Diseases and Chemicals

Pests and diseases are not serious in California at present. However, spraying is necessary in most older vineyards and in established kiwifruit districts. Looper worms, especially Omnivorous Leaf Roller (O.L.R.), and small white scale (Greedy, Latania, Ivy, and Oleander scales) are increasing problems to California growers. These pests require 1-3 sprays per year in grape growing areas of the San Joaquin Valley and one spray in other areas. Worms and scale are perennial problems for New Zealand growers necessitating 4-6 sprays per year. Soil diseases such as Armillaria mellea (oak root fungus) and Phytophthora sp. (crown rot) are fatal to kiwifruit vines. Vines growing in low spots, in saturated soils, or in standing water are likely to be killed by crown rot. Too much wetting of the trunk and crown by frequent irrigations increases Phytophthora. Saturated soils will kill vines during any time of the year.

Rootknot and lesion nematodes are damaging to kiwifruit roots if the numbers of nematodes are large. When kiwifruit follow crops infested with these nematodes, the soil should be fumigated with a good nematacide before planting vines.

Fruit in storage may show gray Botrytis mold and other forms of decay when it is injured or becomes soft. Several chemicals to control Botrytis are being tried as sprays but none are proven or widely used in California.

Absence of chemicals registered in the United States, Japan, and Europe for pest, disease, and weed control is a problem of the kiwifruit industry. In 1988, there were at least two chemicals registered in California for worm control, two for scale control, two contact herbicides (with permit), and two for preemergent weed control.

Fertilizer

Fertilization is important in kiwifruit culture and consists mostly of nitrogen fertilizer applied two or more times per year. Growers should avoid using too much, too close to plants, and should use minimum fertilize the first year after planting. Young plants that grow vigorously late in the fall from heavy use of nitrogen and water in September and October are very prone to winter frost damage. For full-bearing vines, use 1 pound of nitrogen per plant or 150 pounds per acre. One pound of nitrogen is equal to 2.2 pounds or urea or 5 pounds of ammonium sulfate. For bearing vines, at least 50-60% of nitrogen should be applied in March-April and the balance in May, June and July. Liquid feeding in irrigation is often used applying about 100 ppm nitrogen or 10 pounds nitrogen per acre per week. Younger plants should receive proportional amounts during the year depending on age. Thus, second leaf plants can have 0.2 lb of nitrogen per plant per year, 3rd leaf—0.4 lb., 4th leaf—0.8 lb., and 5th leaf—a full pound of nitrogen per year.

Use of potassium fertilizer maybe necessary in older vineyards in the Sacramento Valley Zinc and iron are sometimes needed by plants where deficiency symptoms appear or pH needs to be lowered by sulfur applied to the soil or acid in the irrigation water.

Pruning

Most pruning in California is done during the winter while New Zealand growers do as much summer pruning as winter pruning. In the hot California climate, summer shade must be maintained over the fruit, while in New Zealand growers remove part of the summer shoot growth to let light into their plants to encourage fruit bud formation for the next year's crop. Despite these differences, California and New Zealand yields are similar. Some summer pruning to reduce shade and vine growth and encourage better fruit bud development needs to be performed in California.

Normally kiwifruit vines are trained to a single trunk. All rootstock shoots must be cut off to prevent their growth and competition with the grafted top. After the strongest trunk cane of the grafted top grows above the trellis, it is cut off just below the trellis wire and two canes are encouraged to grow in opposite directions down the center wire of the trellis forming two main arms or cordons from which all future fruiting canes originate. Each year the cordons are headed 20-30 inches beyond the last cut to encourage cane growth from each bud on the cordon cane. Most new canes produce 4-6 fruit at their base and then form flower buds during the summer along the rest of the cane. Winter pruning of young pistillate vines usually leaves about 5 or 6 flower buds on most canes. On older vines usually 6-12 flower buds are left on canes depending on their diameter. The larger the diameter, the more buds can be left. Pruning in the winter removes most older canes that have fruited for 2 or 3 years. Summer pruning usually consists of cutting back vigorous canes that grow beyond the T-bar into the driveways between the trellis and removing a few vigorous upright growing "sucker-like" canes.

Staminate vines are pruned differently from pistillate vines. Winter pruning in staminate vines consists of cutting out twisted, dead, or weak canes but leaving most canes 3-5 feet long. After flowering and pollination in May, male vines are cut back leaving short, new canes spread on the trellis. New growth appears soon and will grow and produce flower buds for the next year. Since male plants only produce flowers it is best to leave them long before bloom to get maximum flowering. Pruning after bloom restricts male plant size and maintains good annual flowering canes. Growers should avoid overly severe summer pruning since this can cause serious sunburn of the main cordons or arms of the vine. Post-bloom pruning must be done in May or summer heat will cause sunburn damage to the plant. In some cases during very hot weather, white latex paint may be advisable after pruning is finished in May to protect big arms from sunburn damage.

Harvest and Storage

Fruit is hand-picked when about 7% sugar and at a hard stage (14-20 lb pressure) in October or early November. It should be cooled to 32-40°F (0-4°C) within 12-24 hours after picking and stored at 32°F (0°C). Proper cold storage can keep fruit firm for 3-6 months. Kiwifruit should not be stored with other fruit, especially those that produce ethylene since this will cause fruit softening and drastically limit storage time and sale of fruit. Fruit should be packed as soon as picked or if this is not possible then within 1-3 weeks after harvest. During packing, the fruit is sized and placed in plastic trays, then covered or wrapped with clear polyethylene plastic, and put in one-layer flats. These packed flats should be cooled quickly so fruit core temperature is 32°F within 24 hours of packing or storage life will be shortened. Commercial packing is available in most areas. Only battery operated forklifts should be used in storage rooms to avoid generating ethylene which would quickly cause softening of kiwifruit. Storage rooms should be thoroughly aired to remove any residual gases before newly packed fruit are stored. Levels of ethylene in storage should be monitored on a regular basis because a week or more of 10 ppb or more ethylene will hasten fruit softening. Season-long ethylene levels over 5 ppb will shorten storage of kiwifruit.

NEW CROP TO SURPLUS CROP

Kiwifruit, possibly the most glamorous new fruit crop of the 20th Century, is an excellent example of how any country can take a new crop and overproduce it in less than 20 years providing some general production information is known and a good cultivar is already selected. California planted the first kiwifruit in 1967 and reached overproduction in 1987. Italy started planing in 1977 and by 1987 they were approaching overproduction. Chile has only grown kiwifruit for eight years but probably will over produce it by 1992—a time span of 12 years. New Zealand, the originator of kiwifruit and the developer of kiwifruit production methods and 'Hayward', took 40 years to reach overproduction, 1947 to 1987.

History shows that a new perennial crop can be rapidly developed if a minimum of essentials are available to growers when they first plant the crop. These essentials are: one or more commercial cultivars; some basic production knowledge (pollination, training, pest control); postharvest handling techniques. Once growers produce and sell two or three crops at a profit new growers will be attracted to the crop and improved prod uction techniques will follow. Then groups of growers, nurserymen and extension agents will tell other growers how to produce the crop. Development money is usually not a serious problem because governments subsidize new industries or investors are looking for a profit from new ventures.

What was the chronology of kiwifruit saga? About 1905 many countries got seed of kiwifruit from China but only New Zealand nurserymen planted seedlings and selected potential varieties. They found 'Hayward' in 1934 plus four other cultivars plus male pollinators. In 1939, Peter McGloughlin planted a few acres of kiwifruit on good deep soil and exported fruit about 1950 to new crops marketer Frieda Caplan in Los Angeles. In the 1950s more plantings were made (ten acres per grower) in the Bay of Plenty. Next came the discovery that plastic wrap over the fruit was necessary to prevent fruit shrivel and that kiwifruit stored alone would keep at 0°C four to six months. Also in the 1950s growers developed pruning and trellis systems, planing pattern and added wind shelters. Consumers liked kiwifruit in the USA, Europe and Japan and paid 79-89cents each sometimes $1.00 each. Big returns attracted growers to this new industry until over 1500 acres (600 ha) were planted in New Zealand by 1970.

California growers entered the picture in 1967 with imported plants and domestically produced plants. Jud Ingram McFarland and Helen Klein in Chico planted thousands of kiwifruit vines from New Zealand and the Tanimoto Family developed two nurseries and sold vines that made Gridley California's kiwifruit capitol. Also, we must not forget Cal-Chico Nursery, the kiwifruit promoter who got the small growers to put their hard earned savings into kiwifruit production. Chico was the center for kiwifruit because USDA had a plant introduction station there with an old 'Hayward' vine (courtesy of Mr. Hayward Wright of New Zealand) and the California male pollinator. These were the source of budwood for most of California's one million vines. Finally, growers formed the California Kiwifruit Growers Organization in 1972 for communication between experienced growers and potential growers. By 1971 the first fruit was sold and by 1974 Kiwifruit returned growers $1.00 per pound net when fruit was exported or sold in the USA. Again, all elements of success were there—commercial cultivar and pollinator, good nursery sources of plants, a grower organization to attract and educate new growers, a profitable market, and an emerging industry learning to grow, pack, store and ship fruit for a profit. New techniques of culture developed every year to make kiwifruit perform better in the hot dry climate of California. In 1984, the California prices for kiwifruit dropped because production was up and in 1984 and 1985 plants were in surplus and the boom was over with production at 8 million packed boxes of 7 pound size.

Next to enter the kiwifruit production scene were France, Japan, and Italy plus a few government subsidies to get started. Today France produces about 7-8 million trays, Japan 6 to 9 million trays, and Italy has 25 million trays ten years after they started despite two major frosts. Finally, we see "under developed" Chile plant four kiwifruit vineyards in 1980 and in 1988 export nearly a million trays, plant 3,000 new acres (1200 ha) and get $2.50 per kilo for all packed fruit. Also, one educational meeting for four days in Santiago attracted 360 people at $200 per person.

What are the essentials concerning kiwifruit growing worldwide?

Climate—700 hours chilling below 7°C; gradual cooling in fall without a severe freeze, 240 frost free days growing season and not too much wind.

Water needs—Available irrigation not just rain because more water is needed than used by grapes or peaches at ET coefficient of 1.1 and an ability to irrigate more than once per week for 6 summer months.

Soil—With good drainage and low in salinity (EC < 0.5 micromhos) pH 5.5 to 7.2

Trellis—Good T-bar or pergola trellis to support vines and fruit weighing 150 kilos per vine.

Pruning requires good techniques to get 80% to 90% renewal of fruit wood annually.

Fruit set requires good bee pollination of flowers to obtain over 800 seeds per fruit where plantings are 8 female to one male plant.

Money—At least $10,000 per acre investment over land cost.

Pests are unarmored scales, looper worms and maybe non-damaging insects that contaminate exported fruit.

Diseases are storage rots (e.g. Botrytis, Alternaria) due to long storage in moisture full plastic bags. Plant diseases are mostly Phytophthora spp. due to constantly wet soil when drainage is restricted.

Crop control to get large fruit sizes is best done by good pruning but may be supplemented by flower and fruit thinning. Crop load of 1,000 fruit per mature vine is very good and more fruit mean smaller, less valuable fruit when packed and sold.

Postharvest air storage is essential for selling large crops over many months. Conditions 0°C temperature, over 90% relative humidity plus fruit in plastic bags placed over trays and packed in boxes, and no ethylene. Store and ship kiwifruit away from apples and handle with electric driven vehicles. Ten parts per billion of ethylene continual in storage will shorten storage life of kiwifruit.

Market development needs good fruit, promotion and reliable supply of fruit. Fruit must be soft—not hard—when it is eaten and appreciated.

REFERENCES


Table 1. Grower returns from packinghouse with good yields and 75% packout.

Vine age Yield/acre Packed
trays/acre
$3.00/tray or
40¢/lb.
$2.20/tray or
30¢/16.
4 2-3 tons (2.4) 500 $1,500 $1,100
5 3-5 tons (4.0) 850 $2,550 $1,870
6 5-8 tons (6.0) 1,250 $3,750 $2,750
7 5-9 tons (7.0) 1,500 $4,500 $3,300
9 8-12 tons (9.5) 2,000 $6,000 $4,400


Last update March 11, 1997 by aw