The Fig: Overview of an Ancient Fruit Ed Stover1 and Malli Aradhya USDA, ARS, National Clonal Germplasm Repository, One Shields Avenue, University of California, Davis, CA 95616 Louise Ferguson and Carlos H. Crisosto Department of Plant Sciences, One Shields Avenue, University of California, Davis, CA 95616 Additional index words. Ficus carica, pollination biology, postharvest The genus Ficus includes species ranging of the prophet Mohammed indicating, ‘‘If The female flowers in edible figs are long in number from 600 to more than 1900, with I could wish a fruit brought to paradise it styled and produce a much more succulent most found in the tropics or subtropics and would certainly be the fig’’ (Condit, 1947). It fruitlet, in contrast to female flowers in only a handful with fruits considered edible is strange to think that this esteemed fruit is the short-styled monoecious wild-type figs (reviewed in Condit, 1969). The cultivated virtually unknown to most U.S. consumers, (Fig. 1, Armstrong, 2006). It is proposed fig, Ficus carica L., (Moraceae), is clearly of except as a brown paste inside distinctive fig (Storey, 1975) that a mutation in the wild fig greatest importance as a source of human cookies. gave rise to the long-styled pistils/succulent food. The fig fruit has long been associated fruitlet in the edible fig (Table 1). As either a with horticulture in the Mediterranean region THE FIG TREE pleiotropic effect or mutation in a tightly (Zohary and Spiegel-Roy, 1975) and is con- linked gene, the edible fig also displays a sidered to have been ‘‘first brought into cul- Fig trees are deciduous, fast growing, and suppression of the androecium. Some so- tivation in southern Arabia’’ (Storey, 1975). spreading in habit, so that they tend to be called caprifigs are reported to be edible and Wild or ‘‘nearly wild’’ figs are reported greater in width than in height. Plants from have a more succulent fruitlet than typical throughout much of the Middle East and cuttings or seed typically grow into single- caprifigs. We do not know of any studies that Mediterranean region (De Candolle, 1886). trunk trees with little training, but trees investigate the anatomic or genetic factors Cultivated figs are reported to have become damaged by freeze or other injury, may that result in these so-called edible caprifigs. established across the Mediterranean region resprout from roots with multiple trunks. Four types of figs are described based 6000 years ago, reaching England by 500 The wood of fig trees is low in density and on cropping/pollination characteristics. The CE (Ferguson et al., 1990). Interestingly, the breaks easily. Branches have a pithy interior. type known as ‘‘common figs’’ requires no fossil record shows a prehistoric distribution Latex, which is irritating to human skin, is pollination to set a commercial crop. Bota- of Ficus carica across southern Europe produced from all broken plant structures. nists use the term ‘‘persistent’’ rather than (De Candolle, 1886). Tree height at maturity varies according ‘‘parthenocarpic,’’ because the fig is not a to genotype and typically ranges from 3 to true fruit. The other two types of edible fig FIG PRODUCTION WORLDWIDE 10 m. Fig trees are very plastic in form and are not persistent and require pollination to can be pruned to many shapes and remain set the main crop of figs. Botanically, these Fig is widely planted in door yards productive. nonpersistent types are classified as ‘‘caudu- throughout the Mediterranean region (and cous’’ and are classed as Smyrna types (e.g., similar climates), and is well adapted to STRUCTURE OF THE FIG FRUIT ‘Calimyrna’, ‘Marabout’, and ‘Zidi’) and San drought and high temperatures. The Food Pedro types (e.g., ‘Dauphine’, ‘King’, and ‘San and Agricultural Organization of the United The fig ‘‘fruit’’ is a composite formed of a Pedro’). The San Pedro types are distinguished Nations (FAO, 2006) estimates that figs are hollow shell of receptacle tissue enclosing by setting a persistent early crop, known as harvested from 427,000 ha, producing more hundreds of individual pedicellate drupelets than one million metric tons per year. Turkey that develop from the individual female flow- ‘‘breba’’ fruit, but require pollination (called ‘‘caprification’’ in figs) to set the main crop. produces 26% of the world’s figs and, when ers lining the receptacle wall, with a small combined with Egypt, Iran, Greece, Algeria, scale-lined opening (called the ostiole or eye) The fourth type, caprifigs (goat figs), and Morocco, these top six producing coun- at the distal end. The tiny flowers and even provides the source of pollen for commercial tries account for 70% of the world’s annual the initial prosyconium are so small that figs plantings of cauducous figs. Fig pollen is production. The United States ranks eighth, were once considered to bear fruit without carried by a unique wasp (Blastophaga with 4% of global fig production in 2005. ever forming flowers. This composite fruit is psenes L.), that has co-evolved with the fig. Fourteen U.S. states produce figs commer- called a ‘‘syconium’’ (reviewed in Condit, (Kjellberg et al., 1987). An important botan- cially, but California produces 98% of the 1947). The mature fruit of the edible fig has a ical component of this co-evolution is the U.S. crop, on 5100 ha, but with a yield per somewhat tough skin, a whitish interior rind, protogynous nature of the caprifig, so that hectare three times the global average. and a sweet, gelatinous pulp comprised of the female flowers are receptive 6 to 8 weeks individual ripe drupelets. The seeds within before anthers mature in the same syconium APPRECIATION FOR FIGS the drupelets range from virtually nonexis- (Condit, 1932). Through this feature, wasps tent to subtly crunchy. enter, pollinate, and oviposit a syconium that Historical works provide evidence of the later has mature pollen as the next wasp sustained importance and appreciation of figs FIG POLLINATION BIOLOGY generation emerges. in the Mediterranean area. Pliny the Elder in AND ITS GENETIC BASIS The blastophagas develop in caprifigs, his Natural History (Bostock and Riley, 1855) which are kept separate from the figs to extolled ‘‘One hundred and eleven observa- In addition to having a distinctive fruit, maximize control of pollination. Ripe capri- tions’’ on the fig. Among them, ‘‘This fruit the fig also has an interesting and distinctive figs are cut and placed in bags or baskets in invigorates the young, and improves the pollination biology. Wild figs produce both trees of the Smyrna and San Pedro-type figs, health of the aged and retards the formation functional male and female flowers within the and are typically supplied at three times in of wrinkles,’’ and (revealing just one more syconium. Fruiting cultivars produce functional regular intervals in May through June in among many observations) ‘‘Mixed with female flowers with abortive hermaphroditic California. The fig growers goal is for only axle-grease it (fig milk) removes warts.’’ flowers ringing the ostiole (Beck and Lord, one wasp to enter each fig. Excessive polli- Among the most interesting comments is that 1988), but vary in their need for pollination. nation increases fruit splitting. In addition, HORTSCIENCE VOL. 42(5) AUGUST 2007 1083 food safety concerns (Doster et al., 1996). In fig breeding, it has been easy to select good maternal parents, because they presumably exhibit the qualities that the breeder is likely pursuing. The strength of California fig breeding has been the focus of identifying and developing improved caprifigs, and cre- ating pollen parents that convey good fruit quality and the persistent trait, which elimi- nates the need for pollination. Key to this strategy was developing an understanding of the genetics of the persistent trait. Interest- ingly, it was found that the allele for persis- tence is dominant but is lethal in the ovule, and thus can only be conferred by the pollen parent (Table 3) (Saleeb and Storey, 1975). When the genetics of persistence and long styles/suppressed androecium are both con- sidered, it becomes apparent that no more than 25% of the progeny will carry both of these traits. BREBA CROP VERSUS MAIN CROP Fig. 1. Floral morphology in caprifigs and edible figs. (Figure used with permission, Armstrong, 2006) Although San Pedro types are in part defined by the setting of a breba crop, some Table 1. Percentage edible figs in progeny based on are as dried fruit. Reflecting this fact, 94% of common figs will also produce brebas. Bre- genotypes of pollen and seed parents (Storey, California fig production is dried or other- 1975). bas are the first figs of the season, setting on wise processed. wood from the previous year, and typically Seed Parent Of the cultivars described by Condit mature in June in the Central Valley of Pollen parent GA/GA GA/ga (1955), 78% are common types, less than California. Some cultivars are grown because GA/GA 0% 0% 4% are San Pedro types, and the remaining of their tendency to produce brebas (which GA/ga 0% 25% 18% are Smyrna types. Cultivars also vary in tend to be larger than main crop figs), are ga/ga 0% 50% such traits as leaf morphology, plant vigor, relatively scarce on the market, and tend to G and A are closely linked loci. fruit external and internal color, fruit flavor/ get a high price as fresh fruit. The main crop G, dominant allele for short-styled pistils; g, reces- degree Brix/titratable acidity, seed character- sive allele for long-styled pistils; A, dominant is produced on the current season’s wood, istics, shape of fruit, skin thickness, ostiole maturing fruit from August through Novem- for functional androecium (and thus pollen); diameter, and duration of fruit production.