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Citrus × paradisi

'Star Ruby' grapefruit

 World grapefruit production
 Nutritional values
 White, pink and red varieties
 Colour of the peel

 Grapefruit hybrids
'Star Ruby' grapefruit
Jorma Koskinen

Much has been written about the origin of grapefruit. We know that it is a relatively recent addition to the large group of citrus fruits. Trying to find the earliest mention of the "forbidden fruit" one invariably lands on Barbados. Although grapefruit are no longer grown on a large scale on the island, it is there the now famous captain Shaddock is reported to have left some pomelo seeds on his way back from the Pacific to England. Fruit of the pomelo trees were apparently naturally hybridised by pollen from a local orange tree and the first grapefruit was born. New studies support this hypothesis. This we know happened around 1700. The name reflects the habit of the tree to grow its fruit in large clusters somewhat resembling the growth pattern of grapes.

By the end of the 18th century grapefruit had spread to other Caribbean islands and Jamaica became the centre of grapefruit cultivation. During the latter half of the 19th century commercial grapefruit production started in Florida, which has to this day remained the grapefruit centre of the world. New grapefruit varieties were introduced to the market and grapefruit became the most valuable export crop of Florida. The state was the biggest exporter of grapefruit in the world until the late 1960's when countries like China, Mexico, South Africa, Israel, India, Argentina and Cuba slowly started to make the necessary investments and began increasing their production. As a country the United States is still the biggest producer of grapefruit. Within the U.S. Florida has 75%, Texas 14%, California 10% and Texas less than 1% of the total production.
'Redblush' grapefruit

'Shambar' grapefruit

Grapefruit 'Marsh'

World grapefruit production 2008

1. United States of America 1 404 320 11. Tunisia 72 000
2. China 607 546 12. Sudan 68 000
3. Mexico 394 865 13. Belize 60 957
4. South Africa 340 927 14. Bangladesh 50 668
5. Israel 241 082 15. Iran (Islamic Republic of) 45 933
6. India 187 000 16. Jamaica 43 500
7. Argentina 180 000 17. Spain 41 120
8. Turkey 167 765 18. Paraguay 39 000
9. Cuba 166 100 19. Swaziland 37 000
10. Brazil 72 000 20. Philippines 36 686
Source: FAO Faostat
Star Ruby grapefruit

'Cocktail' grapefruit

 Grapefruit 'Marsh Pink'

'Redblush' grapefruit
In many parts of the world grapefruit is the customary breakfast fruit. Most grapefruit are chilled, cut in half, loosened from the peel and skin membranes with a special curved grapefruit knife and served fresh with perhaps a touch of sugar or honey.

Grapefruit juice has increased in popularity especially after its promotion as a diet drink started. Many weight-loss diets include grapefruit juice.

The pulp left over after commercial juice extraction is an important source of grapefruit oil, which is used as a flavouring in many soft drinks. The inner peel is a source of pectin and citric acid. Both are used by the food industry in the preservation of other fruits and making jams and marmalades. Naringin, also extracted from grapefruit peel, gives tonic-water its distinctive bitter flavour. 
Pink and red grapefruit nutritional values per 100 g edible part of raw fruit:
Star Ruby grapefruit

Grapefruit 'Star Ruby'

Grapefruit 'Rio Red'

Star Ruby grapefruit

Nutrient Unit Value Nutrient Unit Value
Proximates:     Vitamins:    
Water g 88.06 Vitamin C, total ascorbic acid mg 31.2
Energy kcal 42 Thiamin mg 0.043
Energy kJ 176 Riboflavin mg 0.031
Protein g 0.77 Niacin mg 0.204
Total lipid (fat) g 0.14 Pantothenic acid mg 0.262
Ash g 0.36 Vitamin B-6 mg 0.053
Carbohydrate, by difference g 10.66 Folate, total mcg 13
Fiber, total dietary g 1.6 Folic acid mcg 0
Sugars, total g 6.89 Folate, food mcg 13
Sucrose g 3.51 Folate, DFE mcg 13
Glucose (dextrose) g 1.61 Choline, total mg 7.7
Fructose g 1.77 Betaine mg 0.1
Minerals:     Vitamin B-12 mcg 0
Calcium, Ca mg 22 Vitamin A, RAE mcg 58
Iron, Fe mg 0.08 Retinol mcg 0
Magnesium, Mg mg 9 Carotene, beta mcg 686
Phosphorus, P mg 18 Carotene, alpha mcg 3
Potassium, K mg 135 Cryptoxanthin, beta mcg 6
Sodium, Na mg 0 Vitamin A, IU IU 1150
Zinc, Zn mg 0.07 Lycopene mcg 1419
Copper, Cu mg 0.032 Lutein + zeaxanthin mcg 5
Manganese, Mn mg 0.022 Vitamin E (alpha-tocopherol) mg 0.13
Selenium, Se mcg 0.1      

Source: USDA Nutritional Database

White, pink and red varieties

Grapefruit are divided into three main categories according to the colour of their flesh, juice and skin. Bear in mind that the colour of any grapefruit variety is affected by soil and climate and can vary from one year to the next.

1. White or pale yellow varieties include:
Duncan, Marsh, Oroblanco, Goldens, Wheeney, Sweetie and Melogold.  

Commercially the most important variety of this goup is Marsh.

2. The most common pink or blush varieties (including their various aliases) are:

Henderson (Henderson Ruby)
Marsh Pink (Thompson)
Ray Ruby
Redblush, (Ruby, Ruby Red, Ruby Sweet, Henninger)

3. The most common deep red or strongly pigmented varieties are:

Rio Red (Rio Star)
Star Ruby (Sunrise)

Matters are complicated by the fact that in Texas where only pigmented varieties are grown grapefruit are sold under two marketing names only:

Ruby sweet, which includes the pink varieties Henderson, Ray Ruby and Ruby Red (Redblush), and
Rio Star, which includes the strongly pigmented varieties Rio Red and Star Ruby.

Grapefruit 'Rio Red'

Grapefruit 'Rex Union'

Grapefruit 'Oroblanco'

'Chironja' orangelo

During the growth period the intensity of colour changes due to chemical processes in the fruit. The maturation from flowering to ripe fruit is fairly long. Depending on the geographical area, soil and prevailing weather it can take  8 - 13 months. The colour is medium strong in a fruit that is about to reach maturity and reaches maximum strength during the first weeks of full ripeness. After that the colour is some varieties starts to fade and in a few months decreases significantly. During the whole period the fruit remains fresh and tastes good. This makes it possible to buy fruit of the same variety from the same grower and get different colours during different stages of the season. After several months on the tree many varieties tend to lose some acids, which sweetens the taste further. If left in the tree for too long the taste of some varieties becomes insipid. 

The grapefruit season is exceptionally long. In certain climates it can be all year round. After reaching maturity the fruit does not lose quality but keeps well on the tree and continues to grow in size for several months. In areas where the main harvesting season starts in September - October grapefruit can be picked until the end of April. This prolongs the season and improves productivity. The only drawback is that it delays new flowering but picking the ripest fruit evenly around the tree minimizes the effect. 
'Triumph' grapefruit

Grapefruit 'Oroblanco'

Colour of the grapefruit peel
Grapefruit 'Jaffa Sweetie'
Grapefruit 'Henderson'
The colour of the peel of grapefruit can be quite varied. At its most typical it is golden yellow. Many varieties have differing degrees of pink or red pigment in the rind. Grapefruit hybrids including pomelos can characteristically have varying amounts of green colour in the peel even when fully ripe. Some varieties can in certain climates remain dark green.

This does not mean that the fruit is unripe or of bad quality. The producers often treat the fruit with ethylene gas to change the outer colour in order to make the fruit more attractive to the consumer. This treatment does not affect the taste.  It is quite safe to buy greenish grapefruit and pomelos. They taste just as good and sweet as the yellow and pink varieties.

 LAT Citrus × paradisi  Macfadyen Star Ruby grapefruit
Grapefruit 'Marsh'
'Redblush' grapefruit
Star Ruby grapefruit
 Syn Citrus maxima var. racemosa Osbeck
Grapefruit is assumed to be an offspring of sweet orange as the pollen parent with an unidentified variety harboring the pummelo cytotype: ♀unknown pummelo × ♂C. sinensis.
The grapefruit tree reaches 15 to 20 ft (4.5-6 m) , has a rounded top of spreading branches. The trunk may exceed 6 in (15 cm) in diameter. The twigs normally bear short, supple thorns. The evergreen leaves are ovate, 3 to 6 in (7.5-15 cm) long, and 1 3/4 to 3 in (4.5-7.5 cm) wide, dark-green above, lighter beneath, with minute, rounded teeth on the margins, and dotted with tiny oil glands. The petiole has broad, oblanceolate or obovate wings. 

The fruit is nearly round or oblate to slightly pear-shaped, 4 to 6 in (10-15 cm) wide with smooth, finely dotted peel, up to 3/8 in (1 cm) thick, pale-lemon, sometimes blushed with pink. The pale-yellow, nearly whitish, or pink, or even deep-red pulp is in 11 to 14 segments with thin, membranous, somewhat bitter walls. The fruit is very juicy, acid to sweet-acid in flavour when fully ripe. While some fruits are seedless or nearly so, there may be up to 90 white, elliptical, pointed seeds about 1/2 in (1.25 cm) in length. Unlike those of the pummelo, grapefruit seeds are usually polyembryonic. The number of fruits in a cluster varies greatly; a dozen is unusual but there have been as many as 20.

Please, note that in many languages grapefruit is called Pomelo, the English name of another species (Citrus maxima). In these languages the Pomelo of English is called with an equivalent of is French name Pamplemousse.

 ENG  Grapefruit, Western grapefruit, Common grapefruit
 FRA  Pomelo
 GER  Pampelmuse
 I TA  Pompelmo, Pampelino
 ESP  Pomelo, Toronja,
Photo     © Jorma Koskinen

 LAT Citrus × paradisi ’Duncan’  Grapefruit 'Duncan'

Grapefruit 'Duncan'
is the oldest of the modern commercially grown grapefruit varieties. Its earliest wild forms grew in Florida already in the 1830's.  The commercial propagation of Duncan began in the 1890's. The flesh and juice are quite pale in colour but the taste is still considered to be one of the best of all grapefruit varieties and often serves as a benchmark by which new varieties are judged.

Duncan was the most important cultivar in Florida and Texas for decades and was introduced into all grapefruit-growing areas the world over. After many seedless varieties emerged Duncan lost some of its popularity. Duncan is much used for juice and tinned in syrup as segments or fruit salads.

 ENG Duncan grapefruit
FRA Pomelo Duncan
Photos   © UCR Citrus Variety Collection
© C. Jacquemond / INRA 


 LAT Citrus × paradisi ’Marsh’  Grapefruit 'Marsh'

Grapefruit 'Marsh'
Citrus × paradisi 'Marsh seedless'
(Marsh seedless) was discovered in Florida as a spontaneous seedling in 1860. Because the fruit of the three original seedlings were seedless the new variety was propagated in a nursery and Marsh soon became the most popular new cultivar to be planted. Today Marsh is the leading variety not only in Florida where it originated but also in California, Texas, Arizona, South America, Australia, South Africa, Israel and India.

The fruit is almost completely round, very juicy and rich in flavour. Marsh is medium to late in the season, holds well on the tree and keeps well after harvest. Marsh needs a lot of heat and thrives in hot climates. It also highly sensitive to frost.

 ENG Marsh (seedless) grapefruit
FRA Pomelo Marsh
Photos   © Aggie Horticulture TAMU
© Jorma Koskinen

 LAT Citrus × paradisi ’Melogold’ Grapefruit 'Melogold'
Grapefruit 'Melogold'
Grapefruit 'Melogold'
 Syn Citrus maxima 'Siamese Sweet' × (Citrus × paradisi '4n Marsh')
is a sister hybrid of Oroblanco (next below). They both are hybrids of an acidless Siamese Sweet pomelo and a strain of Marsh grapefruit.

The cross was made in 1958, they were field-planted in 1962. Two cultivars showed special characteristics. The first one was released in 1980 as Oroblanco and the second in 1986 as Melogold.
Information from the UC-Riverside Citrus Variety Collection:
Melogold trees grow vigorously to a large size with a somewhat spreading form. Melogold fruits are oblate in form with a slightly flattened base. The rind is smooth and medium to dark yellow at maturity and thinner than Oroblanco for a similarly sized fruit. The large fruits typically average one pound in weight. The flesh is pale yellow in colour, seedless, tender, and juicy. The flavour is mild, sweet and reminiscent more of pomelo than of grapefruit. Melogold is early in its maturity and holds well on the tree.

 ENG Melogold grapefruit
FRA Pomelo Melogold
Photos   (1) © Gene Lester
(2-3) © Jorma Koskinen

 LAT Citrus × paradisi ’Oroblanco’ Grapefruit 'Oroblanco'
Grapefruit 'Oroblanco'
 Syn Citrus maxima 'Siamese Sweet' x Citrus paradisi '4n Marsh'
Citrus maxima ’Sweetie’
Oroblanco is one of the newest grapefruit varieties. One of its parents is the Siamese Sweet  
pomelo, the other is a Marsh variety growing at the Research Center of the University of California, Riverside.

The cross was made in 1958 and Oroblanco was released for sale in 1980.
The taste is sweet, the flesh pale yellow and seedless. Oroblanco matures early in November - December, and holds well on the tree.

A similar cross made in Israel was released for sale in 1984 under the name 'Sweetie' (see below). These hybrids belong to the varieties that can retain a touch of green even when fully ripe. The Israeli 'Sweetie' can remain dark green, but tastes sweet nonetheless. 

 ENG Oroblanco grapefruit, Sweetie
FRA Pomelo Oroblanco, Sweetie
Photos   © Jorma Koskinen
© Gene Lester

LAT Citrus × paradisi ’Jaffa Sweetie’ Grapefruit 'Jaffa Sweetie'
(Citrus × paradisi) × Citrus maxima

Jaffa Sweetie
is a similar cross to the preceding Oroblanco. It is a cross of grapefruit and pomelo made in Israel and released for sale in 1984.

The shape and juiciness of the fruit resembles grapefruit, but it tastes as sweet as a pomelo. The skin is dark green in the beginning of the season, and it gradually changes to bright yellow.

The fruit is unique by being sweet, yet low on calories (between 24 to 40 calories in one fruit). The reason is that the sweetness does not come from an excess of sugar, but from lack of acid.
Ripe from mid September to March.

Photos   © Jorma Koskinen

 LAT Citrus × paradisi ’Foster’ Grapefruit 'Foster'
Foster pink
originated as a limb sport in a tree of the Walters variety in an orchard near Ellenton, Florida, and was discovered in 1907 by R. B. Foster of nearby Manatee.  It was introduced in 1914 by the Royal Palms Nurseries, Oneco.

Fruit medium-large, oblate to spherical; basal furrows short, radiating; areolar ring indistinct; very seedy.  Primary colour pale to light yellow, but under favourable conditions rind blushed with pink, extending into the albedo.  Rind medium-thick and surface smooth.  Primary flesh colour chamois, but under favourable conditions pink; flesh texture tender and juicy; flavour good.  Medium-early in maturity. Tree is vigorous, large, and productive.

 ENG Foster grapefruit
FRA Pomelo Foster
Photo   © Aggie Horticulture TAMU


 LAT Citrus × paradisi ’Henderson’ Grapefruit 'Henderson'
Grapefruit 'Henderson Ruby'
Grapefruit 'Henderson'
In 1929 frost destroyed the crops of many Texas plantations. The severe weather killed many trees but some started growing again in the spring of the following year.

One of these new sprouts produced fruit with a beautiful ruby colour.  A new variety was born. 'Henderson' is very productive. Some of the best trees can produce 250 seedless fruits a year. Henderson requires effective irrigation but tolerates high temperatures well.

Henderson and Ray Ruby apparently are indistinguishable cultivars discovered in the early 1970s, Henderson as a limb sport of an Everhard strain red grapefruit tree originally planted in 1945 and Ray as four separate young trees planted in a Ruby Red orchard. Both are commercially seedless, of excellent quality and acceptable for gift, fresh and processed markets. Both have more rind blush and two to four times redder flesh color than Ruby Red, with flesh color holding well into late season. Both belong to the Ruby Sweet group together with Ruby Red.

The South African 'Flamingo' grapefruit is an induced mutation of from the Henderson grapefruit and belongs to the strongly pigmented varieties but of slightly lighter colour than Star Ruby.

 ENG Henderson grapefruit
FRA Pomelo Henderson 
Photos   © CCPP
© C. Jacquemond / INRA
© Aggie Horticulture TAMU


 LAT Citrus × paradisi 'Marsh Pink ' Grapefruit 'Marsh Pink'
Citrus × paradisi 'Thompson'
Marsh Pink
(Thompson) originated as a limb sport in a Marsh tree in an orchard owned by W. B. Thompson at Oneco, Florida.  While discovered by S. A. Collins in 1913, it did not become available until 1924 when it was named and introduced by the Royal Palms Nurseries, also of Oneco. Thompson remains of horticultural interest because it was the first seedless pigmented variety to be discovered.

However, other seedless cultivars with superior flesh and peel color were soon discovered and planted in favor of 'Thompson'. Fruit characteristics are essentially identical to 'Marsh' with the exception of the pink flesh color. Sugar and acid levels may be lower than 'Marsh', but not meaningfully so. Fruit hold well on the tree, but flesh color fades as the season progresses.

 ENG Marsh Pink grapefruit, Thompson grapefruit
FRA Pomelo Marsh Pink
Photo   © Aggie Horticulture TAMU


 LAT Citrus × paradisi 'Ray Ruby ' Grapefruit 'Ray Ruby'
Grapefruit 'Ray Ruby'

Ray Ruby was first observed growing in a Texas grove of 'Redblush'  (Ruby Red) grapefruit. 'Ray Ruby' is comparable to 'Redblush' in many respects. Juice and seed content, flesh texture and maturity date are similar for these two cultivars. However, internal colour holds well late in the season for 'Ray Ruby', and greater blush is usually noted for this cultivar than for 'Redblush'. Texas trials suggest that yields and growth characteristics are similar to 'Redblush'. However, no yield data are available for 'Ray Ruby' in Florida where it is recommended only for trial use.

Henderson and Ray Ruby apparently are indistinguishable cultivars discovered in the early 1970s, Henderson as a limb sport of an Everhard strain red grapefruit tree originally planted in 1945 and Ray as four separate young trees planted in a Ruby Red orchard. Both are commercially seedless, of excellent quality and acceptable for gift, fresh and processed markets. Both have more rind blush and two to four times redder flesh color than Ruby Red, with flesh color holding well into late season.

 ENG Ray Ruby grapefruit
FRA Pomelo Ray Ruby
Photo   © CCPP


 LAT Citrus × paradisi ’Redblush’ 'Redblush' grapefruit
'Redblush' grapefruit
'Redblush' grapefruit
    Citrus × paradisi 'Ruby Red'
 Citrus × paradisi  'Ruby Sweet'

or Ruby Red was the leading red grapefruit in Texas for nearly four decades and it is the variety on which Texas' reputation for quality is based. It is said to be a limbsport of the Thompson variety and it was found in Texas in 1929. It is commercially seedless, may have a red blush on the rind and has excellent quality. The early redness of the flesh gradually fades to pink by midseason and buff by spring. Ruby Red is well-suited for gift fruit, fresh market and processing. This was the first citrus fruit variety that was patended (1934).

In Texas Ruby Red belongs to the Ruby Sweet group of grapefruit together with Henderson and Ray Ruby.

 ENG Ruby Red grapefruit, Ruby Sweet grapefruit, Red Blush grapefruit
FRA Pomelo Ruby Red
Photo   © Jorma Koskinen

 LAT Citrus × paradisi 'Shambar ' 'Shambar' grapefruit

'Shambar' grapefruit
Shambar is an old seedless pigmented variety of grapefruit. Its pink flesh resembles the colour of Redblush (Ruby). In suitable conditions Shambar matures earlier than Marsh and sometimes has stronger colour and more flavour than Redblush.

Shambar was discoverd already in 1936 at Corona, California as a limb sport of the Marsh variety. It was introduced in 1945 but has not received wide popularity. Recently however, its production qualities have received some attention due to findings in comparative studies and Shambar has been evaluated in several countries in the Mediterranean basin.

In a 2008 study of grapefruit varieties suitable for tropical conditions (Colima, Mexico) Shambar was found to be among the top four performers for best productivity and fruit colour. The other three were Rio Red, Ray Ruby and Redblush.

 ENG Shambar grapefruit
FRA Pomelo Shambar
Photo   © Jorma Koskinen


 LAT Citrus × paradisi 'Flame' Grapefruit 'Flame'
Flame grapefruit is reported to be from seed of a sport of Ruby Red grapefruit originating in the Houston, Texas grove of C. Henderson.  C. J. Hearn made the final selection, and Flame was released as a new variety in 1987. 
Flame trees grow vigorously to a large size and are reported to be more cold-tolerant than Star Ruby. The fruit has a smooth yellow rind and usually has a pink blush.  The flesh is tender and juicy and has an internal colour almost as dark as Star Ruby.  Flame’s season is mid to late-season; the fruit holds well on the tree with some fading of the internal colour when held past maturity.
Season: February to June
 ENG Flame grapefruit
FRA Pomelo Flame
Photo   © Joe Real


 LAT Citrus × paradisi ’Rio Red’ Grapefruit 'Rio Red'
Grapefruit 'Rio Red'
Grapefruit 'Rio Red'
'Rio Red' was originally a branch sport of 'Ruby'. Its characteristics were retained by the next generation. Rio Red thrives in a hot climate. The fruit is large and often shows some red pigment on the rind. The flesh and juice have a beautiful red colour.

Rio Red was released by Texas A&I University in 1984 as a natural mutation on a tree produced from irradiated budwood which came from Ruby Red seedlings. Tested by Texas A&I University as A&I-1-48S, it produces fruit with a rind color similar to Henderson and Ray and flesh color almost as red as Star Ruby. Other fruit and tree characteristics are similar to Ruby Red except that its deep red flesh color persists throughout the season and it has a strong tendency to sheepnosing. It is a heavy bearer, with a slight tendency to alternation, i.e., exceptionally large crops are often followed by what would normally be considered an average crop. Rio Red is suitable for gift, fresh and processed markets.

As sold in Texas Rio Star grapefruit are the super-red or deep-red fleshed grapefruit of Star Ruby and Rio Red varieties, which comprise about 75 percent of Texas grapefruit acreage. Very few, if any, Star Ruby orchards exist, however, so virtually all of the Rio Star grapefruit in Texas are Rio Red.

 ENG Rio Red grapefruit
FRA Pomelo Rio Red
Photo   (1-2) © Jorma Koskinen
© Aggie Horticulture TAMU

 LAT Citrus × paradisi ’Star Ruby’ Star Ruby grapefruit
Star Ruby grapefruit
Star Ruby grapefruit
Star Ruby grapefruit
Citrus × paradisi 'Sunrise' (see next item)
Star Ruby
(Rio Star) from Texas is a demanding variety to grow. It needs steady heat and humidity but does not tolerate extreme high heat or drought. It is susceptible to infections, pests and cold weather. It is less vigorous than other varieties, grows slowly and the tree and fruit remain smaller than other grapefruit types.

However, in suitable conditions the tree produces attractive red blushed fruit. The flesh and juice are strongly pigmented, up to three times more colourful than 'Ruby Red', and have a bit more sugar and acid. The fruit is low-seeded or seedless and has a very good flavour.

Rio Star grapefruit are the super-red or deep-red fleshed grapefruit of Star Ruby and Rio Red varieties, which comprise about 75 percent of Texas grapefruit acreage. Very few, if any, Star Ruby orchards exist, however, so virtually all of the Rio Star grapefruit is Rio Red.

Star Ruby was released by Texas A&I University in 1970, having originated from irradiated seed of Hudson grapefruit. Its primary attributes are intensely red flesh, good color retention even in late season and a fairly uniform red blush on the rind. Star Ruby commanded good market acceptance and premium prices, but it is sensitive to some herbicides, frequently exhibits winter chlorosis and apparently is more susceptible to Phytophthora and cold damage than other cultivars. Star Ruby is also noted for erratic bearing. Because of its inherent production problems, the freezes of 1983 and 1989 and the introduction of Rio Red in 1984, Star Ruby has essentially disappeared from the Texas industry.

 ENG (Texas) Star Ruby grapefruit
FRA Pomelo Star Ruby
Photo   © Jorma Koskinen

Grapefruit hybrids

Orangelos and more

Orangelos are hybrids of grapefruit and orange. As might be expected these often natural hybrids show characteristics of both parents to various degrees. Chironja is more grapefruit-like whereas Poorman shows more signs of orange. Sometimes even such established old grapefruit varieties as Imperial, Royal and Triumph are considered natural hybrids with orange. The parentage of Wheeny and Smooth Flat Seville is debated but both show many characteristics of orangelos and Smooth Flat Seville is included here in grapefruit hybrids. Rex Union shows all the characteristics of an orangelo but is reportedly a hybrid of Seville orange and a pomelo. Cocktail is a complicated hybrid of  two mandarins and a pomelo.

 LAT Citrus × paradisi 'Chironja ' 'Chironja' orangelo

'Chironja' orangelo
Chironja comes from Puerto Rico and exhibits resemblances to both the orange and grapefruit, particularly to the latter. The name is a combination of Chi(na), the local term used for the sweet orange, and (to)ronja, the Spanish word for grapefruit.

Chironja was found in 1956 as a wild seedling tree in the mountainous section Puerto Rico. Later other seedling trees were found in isolated areas of the coffee zone.

The fruit is large (grapefruit size) and has a few seeds. Rind is medium-thin, smooth, moderately adherent but easily peelable. Segments about 10, central axis medium-large and semi-open. Flesh is yellowish-orange, tender and very juicy. The flavour is mild, lacking the bitterness of the grapefruit. Midseason in maturity and fruit holds well on tree. Tree is vigorous, large, and grapefruit-like; leaves broadly winged, somewhat cupped, and margins irregularly undulate. Unlike true grapefruits where fruit grow in large clusters, the fruit of Chironja are borne singly. 

 ENG Chironja orangelo
Photos   © Gene Lester


 LAT Citrus × paradisi 'New Zealand Grapefruit ' New Zealand Grapefruit

Poorman orange
  Syn  Poorman Orange
A seedy, orange-fleshed fruit that matures slightly earlier than grapefruit because of its lower acidity. It is known by various names, including 'New Zealand Grapefruit', and 'Poorman Orange'. The fruit and tree are very similar to grapefruit, but it is probably a pomelo hybrid or a natural tangelo that may have originated in China or Australia.  This is also suggested by the monoembryony of the seeds (they will not grow true to type). The fruit has some resemblance to the Attani of India and the Natsudaidai and Asahikun of Japan. 
A total heat requirement considerably lower than for any of the true grapefruits is indicated by the earlier maturity of Poorman and the fact that it ripens in New Zealand and parts of southern California where there is insufficient heat for any of the regular grapefruit varieties.

 ENG New Zealand Grapefruit, Poorman, Poorman's orange, Kawau, Sun fruit
FRA Tangelo Poorman
Photos   © Aggie Horticulture TAMU
© Gene Lester


 LAT Citrus × paradisi 'Rex Union' Grapefruit 'Rex Union'
Grapefruit 'Rex Union'
Rex Union was found around 1930 in South Africa. It has never been commercially grown. The exact origin of this variety has not been established but it is believed to be a naturally occured hybrid of Seville orange and pomelo. The external colour is strong orange and the internal colour also exhibits a shade of pale orange when fully ripe.

Fruit are large, normal grapefruit size. Tree is medium-size and compact. The fruit tend to hang on the lower limbs. The UCR CVC website reports that Rex Union makes excellent marmalade because it is not necessary to peel the fruit. You just cut the whole fruit into pieces and boil it in a sugar and water mixture.

 ENG Rex Union grapefruit
FRA Pomelo Rex Union
Photo   © Jorma Koskinen


 LAT Citrus × paradisi 'Smooth Flat Seville ' Smooth Flat Seville
Smooth Flat Seville
  Syn  Citrus × paradisi 'Smooth Seville'
Smooth Flat Seville
is an old Australian fruit that is thought to have originated as a seedling of unknown parentage and has generally been regarded as a sweet orange and grapefruit hybrid. Its age and numerous resemblances to Poorman (New Zealand Grapefruit above), however, suggest that it may be of similar origin and possibly a sister seedling.

Fruit is similar to Poorman in size, form, and flavour, but rind surface is very smooth. Both rind and flesh colour is reddish-orange. Tree and foliage similar to Poorman but tree commonly more vigorous and larger. Younger branches also exhibit dark bark streaks characteristic of Poorman.

Like Poorman, Smooth Seville has a lower heat requirement for maturity than the grapefruit and hence ripens earlier and serves as a satisfactory substitute.

 ENG Smooth Flat Seville, Smooth Seville
Photos   © Gene Lester


 LAT Citrus × paradisi 'Triumph ' 'Triumph' grapefruit

'Triumph' grapefruit

Triumph was the first named grapefruit variety. It was released in 1884 and soon became very popular and a much-planted variety. The parent tree was found near the Orange Grove Hotel in Tampa, Florida. It was soon suspected that the seedling tree was a hybrid, perhaps an orange - grapefruit hybrid, a natural orangelo. Triumph lacks the bitterness of a typical grapefruit and the taste has a strong sweet orange flavour.
The seedy, pale yellow, medium-sized fruit are a little flattened both at the top and bottom. With the subsequent arrival of seedless grapefruit varieties Triumph has lost popularity. Triumph never achieved commercial importance but continues to be planted in private orchards for home use. The strong flavour remains exceptional.

The Jackson LS (low-seeded) variety of South Africa is said to be a seedless budsport of Triumph. It is marketed under the Sweet SunriseTM name.

 ENG Triumph grapefruit
FRA Pomelo Triumph
Photos   © Jorma Koskinen


 LAT Citrus × paradisi ‘Cocktail’ 'Cocktail' grapefruit
'Cocktail' grapefruit
'Cocktail' grapefruit
Citrus maxima 'Siamese Sweet' × Citrus reticulata 'Frua'


Although called a grapefruit Cocktail is actually a hybrid of Siamese Sweet pomelo and Frua mandarin, which is a cross of King mandarin and Dancy tangerine. To be precise Cocktail is 1/4 King mandarin, 1/4 Dancy tangerine and 2/4 Siamese Sweet pomelo, which explains its other name Mandalo.

Cocktail trees are large and vigorous in warmer areas. In cooler climates the tree has a very compact, almost dwarf habit growing about 5-8 ft tall. It is very productive bearing its fruit in clusters. The fruit can vary from the size of an orange to the size of a grapefruit. It has a thin, smooth, yellow rind, which is easy to peel. The flesh is seedy, yellow-orange in color, and exceptionally juicy. The flavor is unique and pleasantly sub-acid.

Cocktail matures in early winter and the fruits hold well on the tree. It is an excellent variety to try in cooler areas, where it can hang until ripe. Cocktail is usually available from November to February.

The cross was made at Riverside in 1966.  The variety was never officially released but found its way to the public sector, where it became known as Cocktail grapefruit. Its proper place, however, is in the pomelo hybrids.

Besides being good for eating fresh Cocktail is reported to be good for making marmalade, candied peel and syrup.

 ENG Cocktail grapefruit
FRA Pomelo Cocktail
Photo   (1-2) © Joe Real
(3) © Gene Lester
(4) © Jorma Koskinen

Performance of various grapefruit (Citrus paradisi Macf.) and pummelo (C. maxima Merr.) cultivars under the dry tropic conditions of Mexico
Becerra-Rodríguez Salvador (1) ; Medina-Urrutia Víctor Manuel (1) ; Robles-González Marciano Manuel (1) ; Williams Timothy (2) 
(1) INIFAP-Campo Experimental Tecomán, CP 28100, Tecoman, Mexico
(2) Department of Botany and Plant Sciences, University of California, CA, Riverside, USA
Euphytica Y. 2008, vol. 164, No. 1, pages 27-36 [10 pages] [bibl. : 3/4 p.]

Page was revised and up-dated 04 March 2021

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