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The Origins of Red Pigmented Grapefruits and the Development of New Varieties

Authors:

Abstract

The first pink pigmented grapefruit variety, Foster, was discovered in Florida in 1907 as a budsport of Walters grapefruit. The second, Thompson Pink, was also found in Florida in 1913 as a budsport on a Marsh tree. Both Marsh and Walters are derived from Duncan grapefruit. Thompson grapefruit was planted in south Texas where it produced two budsports with indistinguishable darker pink pigmented fruits, Ruby Red in 1929, and Redblush in 1931; these two were later widely planted in Texas, Florida and elsewhere. Further Thompson budsports lead to other minor darker varieties, such as Shambar (California), and Burgundy (Florida). Induced radiation mutants were produced from two Texas sources; irradiated seed of Hudson, a dark red seedy variety derived from a Foster Seedless budsport, lead to Star Ruby (1959), and irradiated nucellar Ruby Red budwood produced the non-commercial A&I 1-48 (1971), which in turn produced a darker budsport, Rio Red (1976), the main variety now grown in Texas and Mexico. Further variety development has produced several other dark red varieties: Ray Ruby, a Ruby Red budsport (Texas, 1970); Flame, a Henderson seedling (Florida, 1983); Nel Ruby, a Ray Ruby seedling (South Africa, 1987); Rouge La Toma, a Ruby Red budsport, and its own seedling, Oran Red (Argentina, 1989). Because Rio Red has some shape and late season external appearance drawbacks, an active program to find alternative varieties for Texas has been initiated. Budwood and/or seed from varieties found and developed elsewhere have been introduced, new budsports discovered on A&I 1-48 trees are being tested, plants from fruit chimeras and chromosome transfer have been established, and irradiation of budwood, seed and tissue culture of several varieties has been carried out. grown in Texas is grapefruit, all of it pigmented (da Graça and Sauls, 2000). It is estimated that pink and red varieties account for 75% of all sales of US grapefruit (Saunt, 2000). In Florida, 59% of all grapefruit propagations are now pink and red varieties (Kesinger, 2002), in Israel they constitute 52% of the plantings (M.Bar-Joseph, pers.comm.), and in South Africa pigmented types were expected to overtake white by 2003 (Stanbury, 1996). In Argentina, pink and red varieties comprise 94% of grapefruit production (Accari, 2000), in California it is approximately 95% (T.Batkin, pers.comm.), and in Turkey 70% (Anon., 2003). In Spain, dark red varieties have almost completely replaced white and even pink ones (Porras et al., 1996).
Proc. Int. Soc. Citriculture, 2004. 369-374.
The Origins of Red Pigmented Grapefruits and the Development
of New Varieties
J.V. da Graça, and E.S. Louzada
Texas A & M University-Kingsville, Citrus Center, Weslaco, TX 78596, USA
J.W. Sauls
Texas Cooperative Extension, Texas A & M University, Agricultural Research & Extension Center, Weslaco, TX
78596, USA
Additional index words. Grapefruit parentage, grapefruit family tree
Abstract. The first pink pigmented grapefruit variety, Foster, was discovered in Florida in 1907 as a
budsport of Walters grapefruit. The second, Thompson Pink, was also found in Florida in 1913 as a
budsport on a Marsh tree. Both Marsh and Walters are derived from Duncan grapefruit. Thompson
grapefruit was planted in south Texas where it produced two budsports with indistinguishable darker pink
pigmented fruits, Ruby Red in 1929, and Redblush in 1931; these two were later widely planted in Texas,
Florida and elsewhere. Further Thompson budsports lead to other minor darker varieties, such as
Shambar (California), and Burgundy (Florida). Induced radiation mutants were produced from two Texas
sources; irradiated seed of Hudson, a dark red seedy variety derived from a Foster Seedless budsport, lead
to Star Ruby (1959), and irradiated nucellar Ruby Red budwood produced the non-commercial A&I 1-48
(1971), which in turn produced a darker budsport, Rio Red (1976), the main variety now grown in Texas
and Mexico. Further variety development has produced several other dark red varieties: Ray Ruby, a
Ruby Red budsport (Texas, 1970); Flame, a Henderson seedling (Florida, 1983); Nel Ruby, a Ray Ruby
seedling (South Africa, 1987); Rouge La Toma, a Ruby Red budsport, and its own seedling, Oran Red
(Argentina, 1989). Because Rio Red has some shape and late season external appearance drawbacks, an
active program to find alternative varieties for Texas has been initiated. Budwood and/or seed from
varieties found and developed elsewhere have been introduced, new budsports discovered on A&I 1-48
trees are being tested, plants from fruit chimeras and chromosome transfer have been established, and
irradiation of budwood, seed and tissue culture of several varieties has been carried out.
Grapefruit (Citrus paradisi Macf.) is a relatively recent
natural hybrid of pummelo (C. grandis (L.) Osb. = C. maxima
(Burm.) Merrill) and sweet orange (C. sinensis (L.) Osb.).
While there is some confusion about its exact origins and
early movements, it appears to have originated in Barbados,
probably in the seventeenth or eighteenth century. What
information is available has been reviewed in detail by
Sinclair (1972), Kumamoto et al. (1987) and Gmitter (1995).
Unlike its one parent, the pummelo, grapefruit is
polyembryonic, and was moved as seed to several Caribbean
islands including Jamaica, Cuba and the Bahamas.
Grapefruit was introduced as seed into Florida early in
the nineteenth century by Count Odette Philippe. The oldest
variety in the United States is Duncan, a seedy white-fleshed
variety which originated from a seedling planted in about
1830, but only named in 1892. All known grapefruit varieties,
including the pink and red pigmented varieties, can be traced
back to this source. Rouse et al. (2001) recently reviewed the
origins of grapefruit varieties currently grown in the United
States. The purpose of this paper is to combine this
information with varieties selected elsewhere, and to describe
current new variety development in Texas. Over 70% of the
citrus commercially grown in Texas is grapefruit, all of it
pigmented (da Graça and Sauls, 2000). It is estimated that
pink and red varieties account for 75% of all sales of US
grapefruit (Saunt, 2000). In Florida, 59% of all grapefruit
propagations are now pink and red varieties (Kesinger, 2002),
in Israel they constitute 52% of the plantings (M.Bar-Joseph,
pers.comm.), and in South Africa pigmented types were
expected to overtake white by 2003 (Stanbury, 1996). In
Argentina, pink and red varieties comprise 94% of grapefruit
production (Accari, 2000), in California it is approximately
95% (T.Batkin, pers.comm.), and in Turkey 70% (Anon.,
2003). In Spain, dark red varieties have almost completely
replaced white and even pink ones (Porras et al., 1996).
The Origin of Pigmented Grapefruits
The pigments responsible for the pink or red color in
grapefruit were identified by Matlack (1935) as lycopene and
β-carotene. Khan and MacKinney (1953) found that the
increase in color in one of the early pink varieties, Thompson
Pink, was due mainly to β-carotene, but the darker coloration
in one of its mutants, Ruby Red, was due largely to increased
lycopene levels. The decrease in flesh color later in the
season was shown to be due to decreasing lycopene levels
rather than β-carotene (Ting and Deszyck, 1958). The
presence of lycopene is not restricted to pigmented
grapefruits. A number of pink and red pummelos and hybrid
varieties are known, such as Chandler, Siamese Pink, and
Thong Dee (Hodgson, 1967), Hirado Buntan, Pomelit and
Java Shaddock (Saunt, 2000) and Honyou (Lin and Zhang,
2000), indicating that the genetic potential of lycopene
synthesis was probably present in the pummelo parent. Traces
of lycopene have even been reported in white grapefruit
before maturity (Cameron et al., 1964). The other parent of
grapefruit, sweet orange, also has lycopene-producing
varieties – namely Sarah, a pink budsport of Shamouti found
in Israel (Monselise and Halevy, 1961), and Cara Cara navel,
Proceedings of the International Society of Citriculture, February 2004, Vol. I. 369
a red-fleshed mutation found in Venezuela in 1976 (Saunt,
2000).
Pigmented grapefruit varieties are all derived from two
white-fruited seedlings of Duncan grapefruit in Florida,
namely Marsh (found around 1860) and Walters (discovered
in 1887). The first pink fruit, with pigmentation in the
membranes separating the pulp vesicles, was found on a
Walters budsport in 1907, and was named Foster (Shamel,
1920). Then in 1913, a budsport of Marsh was found with
fruit having pigmentation in the pulp (Robinson, 1921). It
was first named Pink Marsh, and then released and renamed
Thompson Pink in 1924 (Webber, 1943). Limited areas of
both of these varieties were planted in Texas where a new
citrus industry was being developed in the Lower Rio Grande
Valley (Sauls, 1988) and produced further budsports there
with darker pigmented fruits, which have led to a number of
different varieties in Texas and elsewhere (Fig.1). Thompson
Pink is still commercially grown in California (Batkin,
pers.comm.) and Australia (Saunt, 2000).
The Texas Varieties. Thompson Pink trees were planted
in Texas in 1924, and in 1929 the first darker fruit were found
on a budsport (Dewald, 1938; Maxwell, 1948). This was first
called Henninger Ruby Red, later renamed Ruby Red and
patented in 1934, becoming the first citrus variety to receive a
plant patent in the US (US Plant Patent No. 53) (Hodgson,
1967). In 1931, another budsport was found and initially
named Webb Redblush, later shortened to Redblush; the
name ‘Red Marsh’ is sometimes applied to both of them
(Hodgson, 1967). These two selections are indistinguishable.
They were introduced to many other areas where they became
important commercial cultivars. A number of other
pigmented fruiting budsports of Marsh [Ballard Red,
Stanfield Red] and Thompson Pink [Fawcett, Langford Red,
Curry Red Radiance, Shary Red, Riddle Red Gold] were
found between 1927 and 1942 (Fawcett, 1948; Hensz, 1981;
Maxwell, 1948; Waibel, 1953), but comparative studies could
not determine any significant differences between them and
Ruby Red (Krezdorn and Maxwell, 1959; Waibel, 1953). The
source of Fawcett is in dispute – Waibel (1953) states that it
was a Foster budsport, but Fawcett (1948) lists it as a
Thompson Pink mutation. Ruby Red is still propagated
extensively in Florida (Kesinger, 2002), and Turkey (M.
Seker, pers.comm.), and is grown in parts of India (Singh et
al., 2002) and China (Shen, 2000). Small plantings can also
still be found in other places such as California (Batkin,
pers.comm.), Texas (Anciso, 2002), Cyprus (Kyriakou,
pers.comm.), Israel (Bar-Joseph, pers.comm.), South Africa
(Barry and Veldman, 1996) and Argentina (Accari, 2000), but
its popularity is declining.
In 1930, a Foster Seedless tree, which itself was derived
from a Foster budsport (Dewald, 1938), was found bearing
very dark red fruit on post-freeze recovery growth (Hensz,
1966). This was named Hudson, but its seediness meant it
was not commercially developed.
In 1970 a tree derived from a Ruby Red source was
found to have deeper red flesh and peel, in between Ruby
Red and Star Ruby in color; it was named Ray Ruby and
released in 1977 (Hensz, 1978). A few orchards are planted in
Texas (Anciso, 2002) and Israel (Bar-Joseph, pers.comm.),
and recently it has become the most propagated pigmented
variety in Florida (Kesinger, 2002). In 1973, a limb on an
‘Everhard strain of red grapefruit’ was found with dark red
fruit, and was later named Henderson (Maxwell and Rouse,
1980). Saunt (2000) also gives this origin, but in addition
equates Everhard with Fawcett. Hensz (1981) states that
Henderson was derived from a Ruby Red budsport, and
C.Everhard (pers.comm.), whose father propagated the trees,
believes the Fawcett claim is incorrect, and that ‘Everhard’
was probably a Ruby Red strain. Henderson is grown, mainly
as a minor variety, in several places including Texas (Anciso,
2002; Sauls, 1998), Argentina (Accari, 2000), Turkey (Seker,
pers.comm.) and South Africa (Stanbury, 1996). Other Ruby
Red mutations found in Texas in the 1970s, namely Wilshers,
Longwell and Dittman, all have similar characteristics
(Hensz, 1981).
All of the above varieties were the products of natural
mutations. Two other important varieties were the result of
induced mutations using irradiation. In 1959, thousands of
Hudson seeds were irradiated primarily to eliminate the
seediness; this led to the selection and release of Star Ruby
in 1970 (Hensz, 1971). It was not a very successful variety in
Texas because of its irregular bearing characteristics (Burger,
1982; Leyden, 1983), and only a small amount is now
produced (Anciso, 2002), but it is grown widely elsewhere; in
some cases its success may be due to the use of different
selections, for example in South Africa, where it is the most
popular red variety, the selection used was derived from a
Star Ruby seedling (Burdette et al., 1988; Barry and
Veldman, 1996). It is also grown extensively in Australia
(Anon., 2002), Israel (Bar-Joseph, pers.comm.), Spain (Porras
Castillo et al., 2001), Cyprus (A. Kyriakou, pers.comm.), and
Turkey where it comprises 60% of total grapefruit production
(Sarigedik, 2003), although in the latter two countries,
problems with alternate bearing and Phytophthora have
resulted in moves towards other varieties (Kyriakou,
pers.comm.; Seker, pers.comm.). Plantings of it were reported
to be increasing in Cuba (Pardo et al., 1992), and its
introduction into Chile dramatically changed the industry
(Ortúzar et al., 1996). California (Batkin, pers.comm.) and
China (Shen, 2000) also produce some Star Ruby, and in
Brazil, where grapefruit is a minor crop, it is being evaluated
(Donadio et al., 1996).
Budwood from a nucellar Ruby Red source was
irradiated in 1963, and one of the products found in 1971 was
a darker pigmented grapefruit designated A&I 1-48. This was
never released commercially, but a budsport from it
producing fruit almost as red as Star Ruby was found in 1976
(Hensz, 1981), and released as Rio Red in 1984 (Hensz,
1985). It is now the major variety grown in Texas (da Graça
and Sauls, 2000; Anciso, 2002), Arizona (G. Wright,
pers.comm.) and Mexico (F. Gómez García, pers. comm.),
and is of some importance in Argentina (Accari, 2000).
Plantings also exist in Cyprus (Kyriakou, pers.comm.), South
Africa (Barry and Veldman, 1996), Israel (5%) (Bar-Joseph,
pers.comm.), Spain (Porras et al., 1996), and Turkey (5%)
(Seker, pers.comm.).
Patil (2000) determined the lycopene levels in the fruit of
several Texas varieties. Star Ruby had the highest (19.23
ppm), followed by Rio Red (16.19), A&I 1-48 (15.67), Ray
Ruby (9.3), Henderson (5.14), Ruby Red (1.98) and
Thompson Pink (1.25).
Proceedings of the International Society of Citriculture, February 2004, Vol. I.
370
Pummelo X Sweet orange
Barbados
17-18th century
Grapefruit
Jamaica/Cuba/Bahamas?
Seedlings 18-19th century
Grapefruit
FL Seedlings 1809
Duncan
FL-Seedling 1830
Marsh
FL Seedling 1850
Thompson
FL Budsport 1913
Burgundy
FL Budsport 1943
Ruby Red
TX Budsport 1929
Redblush
TX Budsport 1931
Shambar
CA Budsport 1936
Walters
FL Seedling 1887
Foster
FL Budsport 1907
Hudson
TX Budsport
1930
Ruben Pink
ARG Budsport
1963
Star Ruby
TX Irradiated
seed 1959
Rouge La
Toma
ARG Budsport
Henderson
TX Budsport
1973
A & I 1-48 –
TX irradiated
budwood 1971
Ray Ruby
TX Budsport
1970
Oran Red
ARG Seedling
1989
Flame
FL Seedling
1983
Rio Red
TX Budsport
1976
Nel Ruby
SA Seedling
1987
Figure 1. The grapefruit family tree, tracing the parentage of the major commercial varieties around the world.
(ARG=Argentina, CA=California, FL=Florida, SA=South Africa, TX=Texas)
Varieties from Other States and Countries. While many
of the new varieties were found in Texas, some additional
pink and red ones have been found elsewhere. In California, a
Marsh budsport similar to Thompson Pink, although with
pigmentation in the separating membranes and rind rather
than in the flesh, was found in 1919 (Shamel, 1920), but
apparently not named or developed further. Another budsport
of Marsh, Shambar, was found in 1936, and is grown in
Argentina (Pirovano, 2002); according to Hodgson (1967), it
resembles Ruby Red, but Porras Castillo and García Lidón
(2003) showed its internal color to be the same as Henderson.
Proceedings of the International Society of Citriculture, February 2004, Vol. I. 371
In 1945 a Redblush seedling selection called CES Redblush
No.3 was selected (Hodgson, 1967).
In Florida, where the story of pigmented grapefruit
began, Burgundy was discovered in 1943-44 as a budsport of
Thompson Pink (Deszyck and Ting, 1959). It has deeper red
flesh than Ruby Red with early season lycopene levels 2.5
times higher, and matures later with better flesh color
retention having five times more late season lycopene levels
(Oberbacher et al., 1960), although the pigment does not
show up well in the peel (Deszyck and Ting, 1959; Hodgson,
1967). It was patented in 1954 (US Plant Patent No. 1276)
(Deszyck and Ting, 1959). There are plantings of it in
Argentina (Accari, 2000). Also in Florida, a Henderson
seedling tree was found in 1983 with flesh almost as red as
Star Ruby; this was released as Flame in 1987 (Anon., 1988;
Rouse et al., 2001). Rouseff et al. (1992) reported that Flame
fruit had considerably less lycopene than either Star Ruby or
Ray Ruby, but that β-carotene levels in all three varieties
were three to five times higher than in Ruby Red. Lee (2000),
however, measured lycopene levels in the juice of several
varieties in Florida and found Flame to have almost as much
as Star Ruby (18.6 vs 20.49 ppm). In addition to Florida,
Flame has been planted in Argentina, largely replacing Ruby
Red (Accari, 2000), and has been introduced into Turkey
(Serat, pers.comm.), Cyprus (Kyriakou, pers.comm.),
Australia (Gallasch, 2000) and South Africa (Burdette et al.,
1992).
In Argentina, a Foster Seedless budsport, Ruben Pink,
was found in 1963 (Foguet, 1983), and a Ruby Red budsport
there was named Rouge La Toma (Foguet et al., 1992)
which is described as having flesh similar to Burgundy; it has
been patented (Foguet et al., 1999). A seedling of this variety
produced darker red fleshed fruit in 1989 and was named
Oran Red (Foguet et al., 1999). Rouge La Toma is in
commercial production in Argentina, although it is being
overtaken by Rio Red and Flame (Accari, 2000). It may be
less affected by stem pitting strains of Citrus tristeza virus
(CTV) than other red grapefruit varieties (Foguet and Foguet,
1990); in South Africa Redblush (da Graça et al., 1984) and
Star Ruby (Marais and Breytenbach, 1996) were found to be
very severely affected by some stem pitting isolates of CTV.
South Africa has based its red grapefruit industry
primarily on a nucellar Star Ruby selection derived from seed
imported in 1972, which does not have the yield variability of
the original Texas selection (Burdette et al., 1988). Another
seedling selection found there is Nel Ruby, a Ray Ruby
seedling with fruit slightly lighter in color than that of Star
Ruby (Burdette et al., 1992) and which is reported to do well
in semi-arid areas with calcareous, high pH soils (Barry and
Veldman, 1996). Nel Ruby has been licensed (patented) in
South Africa (Burdette et al., 1992). Australia has a Star
Ruby selection, Cant Star Ruby, which is derived from seed
introduced from California in 1984 (Anon., 2002), and Bees
Creek Pink which appears to be the same as or similar to
Thompson Pink (Gallasch, 2000).
Red Mexican is a seedy variety of unrecorded parentage
imported as budwood into the USA from Mexico in 1936
(Cameron et al., 1964). In Cuba there is a variety called Ruby
Jagüey, a nucellar Ruby Red which is reportedly very similar
to the parent, though with fewer seed and thinner rind (Bello,
1987), and in India, Ganganagar Red, possibly a Foster
mutation (S. Naqvi, pers.comm.), is described as having
lightish pink flesh with a thinner peel than Foster and less
seed (Gupta et al., 1974).
Marketing names. Pigmented grapefruits are sometimes
sold under marketing names which can include more than one
of the above varieties. In Texas, Ruby Red, Henderson and
Ray Ruby are marketed as ‘Ruby Sweet’, and Rio Red and
Star Ruby as ‘Rio Star’ (Saunt, 2000; Anciso, 2002). In South
Africa, Redblush and similar types are sold as ‘Rosé’, and in
Israel, Star Ruby is packed under the name ‘Sunrise’ and
Redblush as ‘Yarden Red’ (Saunt, 2000).
Future New Varieties for Texas
Although the grapefruit industry in Texas now depends
largely on the production of Rio Red grapefruit for the fresh
fruit market, this variety has some problems such as a higher
tendency than other varieties to produce sheep-nosed fruit
which are unsuitable for packing (Sauls, 1998), and the peel
of late season fruit has a rough appearance. There is therefore
a need to find alternative varieties. Other established
varieties, such as Flame, have been introduced for testing
under Texas conditions, and a search for new varieties has
been initiated. Seedlings of a number of introduced varieties
are being raised for selection, and irradiation of seed,
budwood and tissue cultures of several varieties has been
conducted. A block of A&I 1-48 trees (the parent of Rio Red)
has been maintained at the Citrus Center over the years, and
has recently produced numerous budsports, all with fruit as
red or redder than Rio Red, some with unique flavors. A dark
red budsport of Rio Red has also been found. These are all
being propagated for testing. Plants from seed and recovered
embryos from chimeric fruit of different varieties where half
the fruit has intense red flesh and peel are also being grown.
In addition, research at the Citrus Center into a new
technique, the transfer of single chromosomes by
microprotoplast production and fusion with whole
protoplasts, provides an additional tool for generating new
varieties (Louzada et al., 2002).
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Additional Index words, freeze damage, citrus rehabilitation. Abstract. The Christmas Freeze of 1983 brought below-freez ing temperatures for over 60 continuous hours, with a minimum of 17° F for several hours Christmas morning, and maxima of no more than 24° on both Christmas Eve and Christmas Day. The Texas citrus industry's 70,000 acres was devastated; over 70% of the season's crop was lost, with no production in 1984-85 and only very limited production ex pected in 1985-86.