Fact sheet: Grapefruit
The grapefruit (Citrus × paradisi), is a subtropical citrus tree known for its sour fruit, an 18th-century hybrid first bred in Barbados. When found, it was named the “forbidden fruit”; it has also been misidentified with the pomelo or shaddock (C. maxima), one of the parents of this hybrid, the other being sweet orange (C. × sinensis).
These evergreen trees are usually found at around 5–6 metres (16–20 ft) tall, although they can reach 13–15 metres (43–49 ft). The leaves are dark green, long (up to 150 mm, or 6 inches) and thin. It produces 5 cm (2 in) white four-petaled flowers. The fruit is yellow-orange skinned and largely an oblate spheroid; it ranges in diameter from 10–15 cm. The flesh is segmented and acidic, varying in color depending on the cultivars, which include white, pink and red pulps of varying sweetness. The 1929 US Ruby Red (of the Redblush variety) has the first grapefruit patent.
The fruit has become popular since the late 19th century; before that it was only grown as an ornamental plant. The United States quickly became a major producer of the fruit, with orchards in Florida, Texas,Arizona,and California. In Spanish, the fruit is known as toronja or pomelo.
One ancestor of the grapefruit was the Jamaican sweet orange (Citrus sinensis), itself an ancient hybrid of Asian origin; the other was the Indonesian pomelo (C. maxima). One story of the fruit’s origins is that a certain “Captain Shaddock” brought pomelo seeds to Jamaica and bred the first fruit. But it probably originated as a naturally-occurring hybrid.
The hybrid fruit was documented in 1750 by a Welshman, Rev. Griffith Hughes, who described specimens from Barbados. Currently, the grapefruit is said to be one of the “Seven Wonders of Barbados.” It was brought to Florida by Count Odette Philippe in 1823 in what is now known as Safety Harbor. Further crosses have produced the tangelo (1905), the Minneola tangelo (1931), and he oroblanco (sweetie)(1984). The sweetie has very small genetic and other differences from the pomelo.
The grapefruit was known as the shaddock or shattuck until the 1800s. Its current name alludes to clusters of the fruit on the tree, which often appear similar to grapes. Botanically, it was not distinguished from the pomelo until the 1830s, when it was given the name Citrus paradisi. Its true origins were not determined until the 1940s. This led to the official name being altered to Citrus × paradisi, the “×” identifying its hybrid origin.
The 1929 Ruby Red patent was associated with real commercial success, which came after the discovery of a red grapefruit growing on a pink variety. Only with the introduction of the Ruby Red did the grapefruit transform into a real agricultural success. The Red grapefruit, starting with the Ruby Red, has even become a symbolic fruit of Texas, where white “inferior” grapefruit were eliminated and only red grapefruit were grown for decades. Using radiation to trigger mutations, new varieties were developed to retain the red tones which typically faded to pink, the Rio Red variety is the current (2007) Texas grapefruit with registered trademarks Rio Star and Ruby-Sweet, also sometimes promoted as “Reddest” and “Texas Choice”.
The Florida Department of Citrus states “the primary varieties of Florida grapefruit are Ruby Red, Pink, Thompson, Marsh and Duncan. The fresh grapefruit season typically runs from October through June.”
Planted in Nassau County Extension Demonstration Garden