Kiwifruit (often shortened to kiwi outside Australia and New Zealand), or Chinese gooseberry, is the edible berry of several species of woody vines in the genus Actinidia . [1] [2] The most common cultivar group of kiwifruit ( Actinidia deliciosa 'Hayward') [3] is oval, about the size of a large hen's egg: 5–8 centimetres (2–3 inches) in length and 4.5–5.5 cm (1+3⁄4–2+1⁄4 in) in diameter. Kiwifruit has a thin, fuzzy, fibrous, tart but edible, light brown skin and light green or golden flesh with rows of tiny, black, edible seeds. The fruit has a soft texture with a sweet and unique flavour.
Kiwifruit is native to central and eastern China, with the first recorded description dating back to the 12th century during the Song dynasty. [1] [4] In the early 20th century, cultivation of kiwifruit spread from China to New Zealand, where the first commercial plantings took place. [1] It gained popularity among British and American servicemen stationed in New Zealand during World War II, and was later became commonly exported, first to California in the 1950s. [1] [5]
From the late 20th century, countries beyond New Zealand initiated independent kiwifruit breeding programs, including China and Italy. [6] [7] As of 2023, China accounted for 55% of the world's total kiwifruit production, making it the largest global producer. [8]
Early varieties were discovered and cultivated in China. Common Chinese names for the fruit prior to the 20th century include míhóutáo (Chinese :獼猴桃; trans."macaque peach"), húlítáo (Chinese :狐狸桃; trans."fox peach"), ténglí (Chinese :藤梨; trans."vine pear") and yángtáo (Chinese :羊桃; trans."sheep peach"). [9] [10] [11] Among the early English language names for the fruit were yangtao, the name that was in popular use in the Yangtze River valley areas of central China, Wilson's gooseberry (after British plant collector Ernest Henry Wilson), gooseberry vine, and Ichang gooseberry, the latter referring to Yichang, a port city in Hubei province. [10] The first known reference to the name Chinese gooseberry comes from 1917 in New Zealand, but it is likely that the name was in use before this time. By the 1920s, Chinese gooseberry became the standard name for the fruit in English until the 1950s. [10] In modern-day Chinese, the fruit is often referred to as qíyìguǒ (Chinese :奇異果), a transliteration from English. [12]
In 1959, Turners & Growers, a major New Zealand exporter began calling it "kiwifruit" after being advised by a United States client that quarantine officials might mistakenly associate the unpopular name gooseberries [13] – which grow close to the ground – with suspicion of anthrax. [14] [10] The name kiwifruit was coined by Jack Turner of Turners & Growers, referencing kiwi, an informal name used to describe New Zealanders, which Turner felt that United States servicemen stationed in the Pacific during World War II would have fond associations with. [10] The name was first registered by Turners & Growers on 15 June 1959, [13] and by 1970, all exports from New Zealand used the name kiwifruit. [10]
Numerous myths are associated with the naming of kiwifruit, including that it is a reference to New Zealand's furry, brown, national bird – the kiwi, or that the name Chinese gooseberry was replaced in response to Anti-Chinese sentiment in the United States. [10]
In New Zealand and Australia, the word kiwi alone either refers to the bird or is used as a nickname for New Zealanders; [13] it is rarely used to refer to the fruit. [5] [15] Kiwifruit has since become a common name for all commercially grown kiwifruit from the genus Actinidia. [1] In the United States and Canada, the shortened name kiwi is commonly used when referring to the fruit. [16] [17]
Kiwifruit | |||||||||||||
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![]() "Kiwifruit" in Traditional (top) and Simplified (bottom) Chinese characters | |||||||||||||
Traditional Chinese | 獼猴桃 | ||||||||||||
Simplified Chinese | 猕猴桃 | ||||||||||||
Literal meaning | "macaque peach" | ||||||||||||
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Kiwifruit is native to central and eastern China. [1] The first recorded description of the kiwifruit dates to 12th century China during the Song dynasty. [4] As it was usually collected from the wild and consumed for medicinal purposes,the plant was rarely cultivated or bred. [18] Cultivation of kiwifruit spread from China in the early 20th century to New Zealand,where the first commercial plantings occurred. [1] After the Hayward variety was developed,the fruit became popular with British and American servicemen stationed in New Zealand during World War II. Kiwifruits were exported to Great Britain and then to California in the 1960s. [1] [5]
In New Zealand during the 1940s and 1950s,the fruit became an agricultural commodity through the development of commercially viable cultivars,agricultural practices,shipping,storage,and marketing. [19] In the 1970s,New Zealand's kiwifruit industry experienced significant growth. To support this expansion,the Kiwifruit Export Promotion Committee was established in 1970 to coordinate marketing efforts and later,in 1977,the Kiwifruit Marketing Licensing Authority was formed to set market standards and advise the government,giving growers some control over licensing exporters. [20] The New Zealand Kiwifruit Marketing Board,was later renamed Zespri International Limited in 1997. This rebranding marked a strategic move to enhance global recognition and market presence. [19]
In 1978,China established the National Cooperative Group for Kiwifruit Research,launching a nationwide survey of wild Actinidia germplasm. This effort led to the selection of over 1,400 candidate cultivars. [21] [22] By the early 1980s,China began cultivating kiwifruit commercially,initially planting less than one hectare with the 'Hayward' cultivar from New Zealand. Over the following decades,China's kiwifruit industry expanded significantly,and by 2020,'Hayward' accounted for only 6.3% of total plantings,as domestically bred cultivars gained prominence. [23]
Among these are 'Hongyang',a red-fleshed kiwifruit selected in Sichuan from seedlings raised from wild-collected seeds, [24] 'Jinyan',a yellow-fleshed variety,and 'Donghong',another red-fleshed cultivar,also known as Oriental Red. [25] [26]
The Wuhan Botanical Garden of the Chinese Academy of Sciences (CAS) plays a key role in China's kiwifruit conservation and breeding. It houses the world’s largest kiwifruit gene bank,with 73 validated or protected varieties and 426 high-quality strains,including Donghong,Jinyan,and Jintao. In 2001,it sold exclusive breeding rights for Jintao to the Italian company Jingold,and in 2012,a collaboration with Jingold resulted in the development and patenting of the Jinyan and Donghong cultivars. [27] [28]
The genus Actinidia comprises around 60 species. Their fruits are quite variable,although most are easily recognised as kiwifruit because of their appearance and shape. The skin of the fruit varies in size,hairiness,and colour. The flesh varies in colour,juiciness,texture,and taste. Some fruits are unpalatable,while others taste considerably better than most commercial cultivars. [1] [29]
The most commonly sold kiwifruit is derived from A. deliciosa (fuzzy kiwifruit). Other species that are commonly eaten include A. chinensis (golden kiwifruit), A. coriacea (Chinese egg gooseberry), A. arguta (hardy kiwifruit), A. kolomikta (Arctic kiwifruit), A. melanandra (purple kiwifruit), A. polygama (silver vine) and A. purpurea (hearty red kiwifruit). [29]
Most kiwifruit sold belongs to a few cultivars of A. deliciosa (fuzzy kiwifruit):'Hayward','Blake' and 'Saanichton 12'. [2] They have a fuzzy,dull brown skin and bright green flesh. The familiar cultivar 'Hayward' was developed by Hayward Wright in Avondale,New Zealand,around 1924. [29] It was initially grown in domestic gardens,but commercial planting began in the 1940s.
'Hayward' is the most commonly available cultivar in stores. It is a large,egg-shaped fruit with a sweet flavour. 'Saanichton 12',from British Columbia,is somewhat more rectangular than 'Hayward' and comparably sweet,but the inner core of the fruit can be tough. 'Blake' can self-pollinate,but has a smaller,more oval fruit,and the flavour is considered inferior. [2] [29]
Kiwi berries are edible fruits the size of a large grape,similar to fuzzy kiwifruit in taste and internal appearance but with a thin,smooth green skin. They are primarily produced by three species: Actinidia arguta (hardy kiwi), A. kolomikta (Arctic kiwifruit) and A. polygama (silver vine). They are fast-growing,climbing vines,durable over their growing season. They are referred to as "kiwi berry,baby kiwi,dessert kiwi,grape kiwi,or cocktail kiwi". [30]
The cultivar 'Issai' is a hybrid of hardy kiwifruit and silver vine which can self-pollinate. Grown commercially because of its relatively large fruit,'Issai' is less hardy than most hardy kiwifruit. [31] [32]
Actinidia chinensis is the species known for both gold (yellow) and red kiwifruits. These varieties are cultivated primarily for their unique color and differing flavours.
The (yellow kiwi or golden kiwifruit) has smooth,bronze skin,with a beak shape at the stem attachment. Flesh colour varies from bright green to a clear,intense yellow. This species is 'sweeter and more aromatic' in flavour compared to A. deliciosa. [33] One of the most attractive varieties has a red 'iris' around the centre of the fruit and yellow flesh outside. The yellow fruit obtains a higher market price and,being less hairy than the fuzzy kiwifruit tastes better without peeling. [29]
Hort16A is a golden kiwifruit cultivar developed by HortResearch,now Plant &Food Research Institute,during the decades of 1980s and 90s. [19] It is marketed worldwide as Zespri Gold. This cultivar suffered significant losses in New Zealand in 2010–2013 due to the PSA bacterium. [34] A new cultivar of golden kiwifruit,Gold3,was found to be more disease-resistant and most growers have now changed to this cultivar. [35] 'Gold3',marketed by Zespri as SunGold is not quite as sweet as 'Hort16A', [36] and lacks its usually slightly pointed tip. Clones of the new variety SunGold have been used to develop orchards in China,resulting in partially successful legal efforts in China by Zespri to protect their intellectual property. [37] In 2021,Zespri estimated that around 5,000 hectares of Sungold orchards were being cultivated in China,mainly in the Sichuan province. [38]
Jintao is a variety of golden kiwifruit developed in China from wild Actinidia chinensis vines. Created in the 1980s by researchers at the Wuhan Botanical Garden,it was introduced to Europe for evaluation in 1998 through a EU-funded project (INCO-DC). Between 1998 and 2000,it was evaluated in collaboration with institutions such as I.N.R.A. in Bordeaux (France),the University of Thessaloniki (Greece),and the University of Udine (Italy). Jintao was later released to European kiwifruit growers for commercial propagation in 2001. In the same year,exclusive breeding rights for the variety were sold to the Italian company Jingold,and production subsequently expanded to multiple locations across Portugal,Chile,Argentina,and South Africa over the following two decades. [39] [40] [41]
The red kiwifruit is a variety of Actinidia chinensis and is distinguished by its red coloured flesh. Its origin can be traced back to China from a natural mutation of gold kiwifruit found in the wild. [42]
In 1982,the first reports of red pulp in kiwifruit were made in Actinidia chinensis fruit in Hubei Province,China,and later from Henan and other parts of China. These discoveries led to the classification of the red-fleshed variant as A. chinensis var. rufopulpa (meaning "red pulp"). [43] [44] This natural mutation set the stage for the development of the Hongyang variety,China's first commercially viable red kiwifruit cultivar. [24] [45]
Hongyang was developed from seeds collected in 1982 from wild Actinidia chinensis plants by the Sichuan Provincial Natural Resources Institute and the Agricultural Bureau of Cangxi County,Sichuan. The seeds were sown in 1984,and by 1986,921 plants had produced their first fruit. In 1990,a plant was selected from these clonal populations and designated as "Red Sun No. 1." Following field trials and evaluation,the variety was officially registered as Hongyang by the Sichuan Provincial Crop Variety Registration Authority in 1997. [46] It also paved the way for development of later red kiwifruit varieties,including Donghong,which by 2023 was the second most widely cultivated red-fleshed kiwifruits in China. [45] [47] Developed through a collaboration between Italian company,Jingold and Wuhan Botanical Garden in 2012,the Donghong variety is also marketed under the name Oriental Red. [26] [48]
In New Zealand,an independent development of a red kiwifruit variety took place through a partnership between Plant &Food Research and Zespri. The Zespri RubyRed variety resulted from a natural breeding cross in 2007. Initially labeled Zes008,the variety underwent further testing and was soft-launched as "Zespri Red" in select markets between 2019 and 2020. It was rebranded as Zespri RubyRed in 2022. The variety is now grown in New Zealand and exported to Japan,China,and Singapore,with plans for global expansion. [49]
Turners &Growers,a New Zealand company and competitor to Zespri,developed a commercially viable variety of red-ringed kiwifruit patented as EnzaRed,which is a cultivar of the Chinese Hongyang variety. [50] [51] [52]
Kiwifruit can be grown in most temperate climates with adequate summer heat. Where fuzzy kiwifruit (A. deliciosa) is not hardy,other species can be grown as substitutes.
Often in commercial farming,different breeds are used for rootstock,fruit-bearing plants,and pollinators. [1] Therefore,the seeds produced are crossbreeds of their parents. Even if the same breeds are used for pollinators and fruit-bearing plants,there is no guarantee that the fruit will have the same quality as the parent. Additionally,seedlings take seven years before they flower,so determining whether the kiwifruit is fruit bearing or a pollinator is time-consuming. [53] Therefore,most kiwifruits,except rootstock and new cultivars,are propagated asexually. [53] This is done by grafting the fruit-producing plant onto rootstock grown from seedlings or,if the plant is desired to be a true cultivar,rootstock grown from cuttings of a mature plant. [53]
Kiwifruit plants generally are dioecious,meaning a plant is either male or female. The male plants have flowers that produce pollen,the females receive the pollen to fertilise their ovules and grow fruit;most kiwifruit requires a male plant to pollinate the female plant. For a good yield of fruit,one male vine for every three to eight female vines is considered adequate. [1] Some varieties can self-pollinate,but even they produce a greater and more reliable yield when pollinated by male kiwifruit. [1] Cross-species pollination is often (but not always) successful as long as bloom times are synchronised.
In nature,the species are pollinated by birds and native bumblebees,which visit the flowers for pollen,not nectar. The female flowers produce fake anthers with what appears to be pollen on the tips to attract the pollinators,although these fake anthers lack the DNA and food value of the male anthers. [54]
Kiwifruit growers rely on honey bees,the principal ‘for-hire’pollinator,but commercially grown kiwifruit is notoriously difficult to pollinate. The flowers are not very attractive to honey bees,partly because the flowers do not produce nectar and bees quickly learn to prefer flowers with nectar.
Honey bees are inefficient cross-pollinators for kiwifruit because they practice “floral fidelity”. Each honey bee visits only a single type of flower in any foray and maybe only a few branches of a single plant. The pollen needed from a different plant (such as a male for a female kiwifruit) might never reach it were it not for the cross-pollination that principally occurs in the crowded colony;it is in the colonies that bees laden with different pollen cross paths. [55]
To deal with these pollination challenges,some producers blow collected pollen over the female flowers. [54] Most common,though,is saturation pollination,in which the honey bee populations are made so large (by placing hives in the orchards at a concentration of about 8 hives per hectare) that bees are forced to use this flower because of intense competition for all flowers within flight distance. [1]
Kiwifruit is picked by hand and commercially grown on sturdy support structures,as it can produce several tonnes per hectare,more than the rather weak vines can support. These are generally equipped with a watering system for irrigation and frost protection in the spring.
Kiwifruit vines require vigorous pruning,similar to that of grapevines. Fruit is borne on 'one-year-old and older' canes,but production declines as each cane ages. Canes should be pruned off and replaced after their third year. In the northern hemisphere,the fruit ripens in November,while in the southern it ripens in May. Four-year-old plants can produce 15 tonnes of fruit per hectare (14,000 lb per acre) while eight-year-old plants can produce 20 tonnes (18,000 lb per acre). The plants produce their maximum at eight to ten years old. The seasonal yields are variable;a heavy crop on a vine one season generally comes with a light crop the following season. [1]
Fruit harvested when firm will ripen when stored properly for long periods. This allows fruit to be stored for up to 8 weeks after harvest. [1]
Firm kiwifruits ripen after a few days to a week when stored at room temperature,but should not be kept in direct sunlight. Faster ripening occurs when placed in a paper bag with an apple,pear,or banana. [56] Once a kiwifruit is ripe,however,it is preserved optimally when stored far from other fruits,as it is sensitive to the ethylene gas they may emit,thereby tending to over-ripen even in the refrigerator. [56] If stored appropriately,ripe kiwifruit is normally kept for about one to two weeks. [56]
Pseudomonas syringae actinidiae (PSA) was first identified in Japan in the 1980s. This bacterial strain has been controlled and managed successfully in orchards in Asia. In 1992,it was found in northern Italy. In 2007/2008,economic losses were observed,as a more virulent strain became more dominant (PSA V). [57] [58] [59] In 2010 it was found in New Zealand's Bay of Plenty Region kiwifruit orchards in the North Island. [60] The yellow-fleshed cultivars were particularly susceptible. New,resistant varieties were selected in research funded by the government and fruit growers so that the industry could continue. [61]
Scientists reported they had worked out the strain of PSA affecting kiwifruit from New Zealand,Italy,and Chile originated in China. [62]
In 2020,the Wuhan Botanical Research Institute of the Chinese Academy of Sciences patented a method for early identification of the sex of kiwifruit plants. [63] [64] [65]
Kiwifruit plants are dioecious,meaning they have separate male and female plants. Crosses between male and female genotypes typically produce male and female offspring in a 1:1 ratio,regardless of ploidy level. Since only female plants bear fruit,male plants are unproductive in commercial breeding programs. Maintaining male seedlings consumes land,labor,and resources without contributing to fruit yield. The breeding process is further hindered by the species' long generation cycle,spanning at least three growing seasons and a period of winter dormancy. Managing large breeding populations over extended periods is resource-intensive,especially for fruit crops like kiwifruit,which require expensive support infrastructure. [65]
To address these challenges,there is a pressing need for sex-linked molecular markers. Early identification of plant sex at the seedling stage enables the efficient removal of male plants,reducing resource waste and improving breeding efficiency. [65]
![]() | 2,362,658 |
![]() | 662,744 |
![]() | 391,100 |
![]() | 317,080 |
![]() | 295,142 |
![]() | 116,029 |
World | 4,433,060 |
Source:FAOSTAT of the United Nations [8] |
In 2023,world kiwifruit production was 4.4 million tonnes,led by China with 55% of the total (table). In China,kiwifruit is grown mainly in the mountainous area upstream of the Yangtze River,as well as Sichuan. [66] Other major producers were New Zealand and Italy (table).
Kiwifruit exports rapidly increased from the late 1960s to the early 1970s in New Zealand. By 1976,exports exceeded the amount consumed domestically. [67] Outside of Australasia,New Zealand kiwifruit are marketed under the brand-name label Zespri. [68] The general name,"Zespri",has been used for the marketing of all cultivars of kiwifruit from New Zealand since 2012. [19] [33] In 1990,the New Zealand Kiwifruit Marketing Board opened an office for Europe in Antwerp,Belgium. [19]
In the 1980s,Italy began cultivating and exporting kiwifruit,leveraging its existing grape-growing infrastructure and techniques. Italy developed yellow-fleshed cultivars,including "Soreli" and "Dorì". [7] Its proximity to the European market further boosted production,and by 1989,Italy had become the world's leading kiwifruit producer. Additionally,Italy's growing season does not significantly overlap with those of New Zealand or Chile,reducing direct competition with these major exporters. [69] [70]
In 1978,China began developing its own kiwifruit cultivars. The Wuhan Botanical Garden,part of the Chinese Academy of Sciences (CAS),played a large role in breeding and improving domestic varieties suited to local conditions. Commercial cultivation initially began in the early 1980s on less than one hectare using the Hayward variety from New Zealand. But by 2020,kiwifruit orchards had expanded to 290,000 hectares and 'Hayward' accounted for only 6.3% of the total planting area,as domestically bred varieties gained prominence. To support commercialization and branding,CASGOLD,the first CAS-backed agricultural brand,was created. By 2023,China had become the world’s largest kiwifruit producer,surpassing Italy and New Zealand. However,most of its kiwifruit is consumed domestically,with little exported. [23] [22]
Nutritional value per 100 g (3.5 oz) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Energy | 262 kJ (63 kcal) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
15.8 g | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Sugars | 12.3 g | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Dietary fiber | 1.4 g | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
0.28 g | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1.02 g | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Other constituents | Quantity | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Water | 82 g | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
†Percentages estimated using US recommendations for adults, [71] except for potassium, which is estimated based on expert recommendation from the National Academies. [72] |
Nutritional value per 100 g (3.5 oz) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Energy | 255 kJ (61 kcal) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
14.66 g | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Sugars | 8.99 g | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Dietary fiber | 3 g | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
0.52 g | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1.14 g | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Other constituents | Quantity | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Water | 83 g | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
†Percentages estimated using US recommendations for adults, [71] except for potassium, which is estimated based on expert recommendation from the National Academies. [72] |
Kiwifruit may be eaten raw, made into juices, used in baked goods, prepared with meat, or used as a garnish. [1] The whole fruit, including the skin, is suitable for human consumption; however, the skin of the fuzzy varieties is often discarded due to its texture. [73] Sliced kiwifruit has long been used as a garnish atop whipped cream on pavlova, a meringue-based dessert. Traditionally in China, kiwifruit was not eaten for pleasure but was given as medicine to children to help them grow and to women who have given birth to help them recover. [1]
Raw kiwifruit contains actinidain (also spelled actinidin) which is commercially useful as a meat tenderizer [74] and possibly as a digestive aid. [75] Actinidain also makes raw kiwifruit unsuitable for use in desserts containing milk or any other dairy products because the enzyme digests milk proteins. This applies to gelatin-based desserts since the actinidain will dissolve the proteins in gelatin, causing the dessert to either liquefy or prevent it from solidifying.
In a 100-gram (3.5 oz) amount, green kiwifruit provides 255 kilojoules (61 kilocalories) of food energy, is 83% water and 15% carbohydrates, with negligible protein and fat (table). It is particularly rich in vitamin C (103% DV) and vitamin K (34% DV), potassium, and has a moderate content of vitamin E (10% DV) and copper, with no other micronutrients in significant content. Gold kiwifruit has similar nutritional value to green kiwifruit, but contains higher vitamin C content (179% DV) and insignificant vitamin K content (table). Both types of kiwifruit are rich in dietary fiber.
Kiwifruit seed oil contains on average 62% alpha-linolenic acid, an omega-3 fatty acid. [76] Kiwifruit pulp contains carotenoids, such as provitamin A beta-carotene, [77] lutein and zeaxanthin. [78]
Allergy to kiwifruit was first described in 1981, and there have since been reports of the allergy presenting with numerous symptoms from localized oral allergy syndrome to life-threatening anaphylaxis. [79]
The actinidain found in kiwifruit can be an allergen for some individuals, including children. [80] [81] [82] The most common symptoms are unpleasant itching and soreness of the mouth, with wheezing as the most common severe symptom; anaphylaxis may occur. [80] [81]
Grown commercially Issai is less hardy than most hardy kiwi.