Notes on Wild Coffea arabica from Southwestern Ethiopia, with some Historical Considerations FREDERICK G. MEYER 1 Introduction trade, just ahead of raw cotton, raw wool, and wheat." The origin and history of cultivated plants In 1961-62, for nearly four months, I offer tantalizing problems for investigation~ visited Ethiopia partly to collect and to particularly to ethnobotanists and plant study the coffee plant which Sylvain (1955) taxonomists. Plants such as maize, soy bean, and Strenge (1956) found growing spon- sesame, the common garden bean, sweet po- taneously in the verdant, evergreen, montane tato, common potato, and some others have rain-forests of the southwestern part of that been so altered by man's influence that the country. The present account is a ,progress wild progenitors often are extremely diffi- report on my collecting trip, with some other cult to determine; in fact, they may no long- data which bear on the history, origin, and er exist at all. Many botanists, unfortu- modern dispersal of this highly interesting nately, are loath to collect cultivated plants, plant. Prior to my visit to Ethiopia, her- which is a pity; and for this reason alone, barium specimens of the coffee plant from the progenitors of some cultivated plants re- rain-forest areas of the country were un- main undocumented and unstudied. available for study. A plant long cultivated and still far from The documented history of C. arabica is being adequately documented from the wild associated almost entirely with cultivated is the Arabica coffee plant, Coffee arabica plants grown in Yemen for perhaps as long L. Legend rather than fact still surrounds as 700 years (Chevalier, 1929), and with the details of origin and natural distribu- plants distributed from Yemen to Java and tion of this plant, although with some inten- to Holland in the late 17th Century and to sive field work in Ethiopia, the question of the New World in the early part of the 18th nativity may not be too difficult to resolve. Century. Now, C. arabica is grown as a com- Yarious travelers, writers, and others long mercial crop in about 80 countries. have suggested that the Arabica coffee plant After investigating the early history of is indigenous to Ethiopia. Lack of factual botanical exploration in Ethiopia, it was evi- data on the wild plant is all the more re- dent that documentation of wild C. arabica markable, especially in view of the long has eluded botanists in the past for reasons and sometimes tedious history of Arabiea best associated with the geographic and coffee as a product of first importance in p~)litical history of the country. woEd commerce. Of interest is a recent re- Current interest in documenting the wild port by the Food and Agricultural Organiza- phase of C. arabica centers in southwestern tion of the United Nations (FAO, 1961), Ethiopia, mainly in the provinces of Illuba- which states that "the value of world coffee bor and Kaffa, where the coffee plant is exports . in the fifties was the most valu- abundant in rain-forest areas visited by the able single agricultural commodity in world writer. Apart from the desire to document the wild plant botanically, a practical need 1 United States l~ational Arboretum, Crops Research Division, Agricultural Research Serv- exists to introduce germ plasm from the wild ice, United States Department of Agriculture, for use in coffee breeding research, especial- Washington, D.C. ly material resistant to the coffee rust fungus l~eceived for publication June 29, 1964. (Hemileia vastatrix). Coexistence of the 136 WILD COFFEA ARABICA I~RO]~ SOUTHWESTERN" ETHIOPIA 137 coffee rust fungus and the coffee plant in tied to the cultivation and disease problems rain-forests of Ethiopia is regarded as sig- of the coffee plant, mainly of C. arabica, nificant to the question of nativity and mod- and the economic aspects associated with ern dispersal of the Arabica coffee plant. marketing of the fruit for the drink. Well- Populations of C. arabica in southwestern man correctly appeals for a concerted effort Ethiopia barely have been tapped as a source to study the taxonomy of wild species of of new germ plasm, so that exploration has Coffea, C. arabica in particular, because of really only begun. its ever important role as the leading crop species of coffee. Taxonomy of Coffea Mostly, coffee research is tied to the Arab- Coflea, a tropical woody genus of the ica coffee plant, a development which has Rubiaceae, established by Linnaeus (1737), been a saga of our times, beginning about consists of 40 to 70 species confined to 1600 when small shipments of coffee from Africa, Madagascar, the Mascarene Islands, Yemen began to appear in western Europe. and Indomalaysia. As compared with research on temperate Auguste Chevalier was the last great au- crop plants, crops grown in the tropics re- thority on the taxonomy of Coffea. His mono- ceive far too little attention from specialists, graph, "Les Caf6iers du Globe," completed especially in the area of taxonomy. Well- before World War II, was published in man, like many others, is cognizant that the 1947. This synopsis enumerates 66 species, wild phase of C. arabica is found in Ethi- four-fifths from Africa, Madagascar, and opia but that "the true wild range of this tho Masearene Islands, and one-fifth from species has still to be fully investigated southern Asia, divided among four sections: botanically, and understood horticulturally. (1) Euco].fea, the rain-forest taxa of tropical It needs serious study in comparison with Africa; (2) Paracoffea, the Asian taxa; (3) other species." As a pathologist, Welhnan Argocoffea, the savanna taxa south of the knows only too well the Hemileia rust disease African rain-forest belt; (4) Mascarocoffea, problem and the serious need to collect new the taxa of Madagascar and the Masearene germ plasm of C. arabica from Ethiopia. Islands. A new monograph of Coflea based upon Species of the section Eucoffea, typified field, garden, and laboratory studies is much by C. arabica, are confined to Ethiopia and needed, to define the limits of the genus the rain-forest belt of the Congo River through a careful evaluation of satellite drainage basin of central Africa and rain- "genera" which now complicate the taxo- forest areas of West Africa. The Arabica nomy of this complex. coffee plant contributes about 75% and C. eanephora Pierre ex Froehn., the so-called Some Biologic Aspects of the robusta coffee plant, about 25% of the world Arabica Coffee Plant supply of coffee. Two other African rain- In several respects, C. arabica, Linnaean forest species, C. liberica Bull ex Hiern and type species and best known member of the C. de~vevrei De Wild. & Dur., contribute in- genus, manifests characteristics which arc significant amounts of commercial coffee, unique among the known taxa of Coffea. mostly to the Scandanavian market. Other The type specimen of C. arabica in the members of the section Eucoffea and some Linn~ean herbarium in London clearly typi- species in the other sections reportedly are fies the plant found by me in the rain-forests used locally. of Ethiopia. Although the Linnaean speci- Wellman's (1961) book "Coffee: Botany, ment marked "India," presumably desig- Cultivation, and Utilization," although pri- nates the country of origin, in Species Plan- marily a literature survey, makes an ad- tarum (1753), Linnaeus clearly regarded mirable contribution in pointing out the nmst Arabia as the native habitat of the plant. urgent problems in modern coffee research Iu the 1Sth Century, various authors re- with suggestions for improvement in areas gHrded Ethiopia as the qountry of origin of long neglected, not the least of which is the C. arabica, but no authentic specimens were taxonomy of wild coffee. Traditionally, available to Linnaeus. It is clear to the problems in coffee research have largely been writer that the cultivated phase of O. arab- 138 ECONOMIC BOTANY ica, long confined to Yemen and then spread report (unpublished) on the discovery of a to other parts of the world, and the spon- tetraploid sucker that strongly resembles C. taneous rain-forest phase of the plant in arabica on a plant of an F 1 cross of C. Ethiopia, taxonomically, are inseparable. eugenioides X C. excelsa. Ploidy in C. arab- Biologically, the Arabica coffee plant differs ica is one aspect about the plant yet to be in several significant aspects from other explained. One cannot rule out that C. arab- species of the genus. ica may actually have been derived as an The Arabica coffee plant has been studied allotetraploid from parents :now extinct. intensively by numerous investigators from Stebbins (personal communication) sug- material cultivated in Brazil, India, Java, gests that a search be made for a diploid and other areas, but the Ethiopian phase of 'race' of C. arabica in rain-forests of Ethi- the plant remains basically unstudied. Some opia, since such a race could be helpful in known facts about the plant are worth enu- explaining the origin of allopolyploidy in merating. For example, C. arabica is the this plant. The situation in C. arabica may only known allopolyploid, autogamous spe- be compared with "a good many 'species' as cies of the genus. All other known taxa of recognized by taxonomists before cytological Coffea are diploid and outerossing (allogam- studies were made, such as Hordeum. 'nodo- ous). In its distribution, C. arabica is ap- sum,' Madia gracilis~ Malacothrix clevelandii, parently allopatric and isolated on the Ethi- Microseris spp., which contain a diploid opian plateau, although the total distribution 'race' and a tetraploid or other polyploid of the plant has yet to be fully determined. 'race,' the latter being actually an allopoly- The closest relatives occur in rain-forests of ploid species derived from a hybrid between the Sudan, some 400 miles to the southwest, the diploid and some completely different across the valley of the White Nile River.