Genetic Resources and Crop Evolution 50: 779 – 787, 2003. 779 2003 Kluwer Academic Publishers. Printed in the Netherlands.

Evolution of sesame revisited: domestication, diversity and prospects

Dorothea BedigianWashington University, St. Louis and Missouri Botanical Garden

Received 19 March 2002; accepted in revised form 13 July 2002

Key words: Africa, Diversity, Domestication, Evolution, Indian subcontinent, Oil plant, Sesamum

Abstract

This is an account of genetic, phytochemical, historical and cultural studies of sesame, Sesamum orientale L. andits wild relatives. The Pedaliaceae family, to which sesame belongs, is found chiefly in tropical Africa, with twounique sections of the genus Sesamum exclusive to India.

Many authors who write about the domestication of sesame reiterate the widely published statement that sesamewas domesticated in Africa. The evidence for this view is critically examined. Genetic and chemical datademonstrate the difficulty of accepting an African origin of the crop. Data are presented to authenticate the Indiansubcontinent as the place where sesame was domesticated.

Introduction the Graeco-Roman world, both for its edible seed andfor its oil. It was domesticated on the Indian subconti-nent (Bedigian 1984, 1985, 1998, 2000; Bedigian etThere are four reasons for communicating this reviewal. 1985, 1986; Bhat et al. 1999; Fuller 2000; Fullerabout evolution in sesame. Some contemporary wri-and Madella 2000; Hiremath and Patil 1999; Powellters have inaccurately represented portions of this1991; Zohary and Hopf 1994, 2001).author’s published work, leading, perhaps, to incor-

rect conclusions. Several authors have in fact omittedor overlooked important research that contributes to

Early literature, nomenclature and synonymythe study of sesame evolution in their reviews. More-over, this work has been duplicated abroad. An Indian

Researchers have published opinions since the time ofdoctoral student recently obtained his degree, redoing th19 century botanist Alphonse de Candole and Jonesthe hybridization experiments that were completed(1886), about the place where sesame domesticationnearly two decades earlier. Finally, recent molecularoccurred. Note that the Latin binomial of sesame,

studies confirm the earlier efforts of this author,Sesamum orientale L., has as synonym S. indicum L.,demonstrating that the progenitor occurs on the Indiana name that remains in common usage.S. orientale issubcontinent. The goal here is to correct erroneousused here to respect rules of nomenclature discussedinferences about the domestication of sesame and toby Seegeler (1989). In itself it does not prove thereiterate the results that provides the basis for thisorigin of a species.author’s conclusions.

Early respected authorities (including Burkill(1953), Dalziel (1955), Darlington (1963), Greenway(1945), Hiltebrandt (1932), Irvine (1953, 1969), Mur-dock (1959), Purseglove (1968), SchweinfurthDomestication on the Indian Subcontinent(1922), Vavilov (1926) [reprinted as Vavilov andDorofeev (1992)]; and Zhukovskii (1962)) suggestedSesame is often described as the oldest oilseed plantan African origin. Later writers often relied, unques-used by humans (Joshi 1961; Weiss 1983; Mabberleytioningly, upon their expertise. The frequently stated1997). It was cultivated during ancient Harappan,belief that sesame originated in Africa is understand-Mesopotamian, and Anatolian eras, and throughout

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able, because the Pedaliaceae family, to which based on successful reciprocal crosses between theSesamum belongs, consists of a dozen other genera putative wild progenitor and the cultivated form.from Africa. Most wild species of Sesamum also Fully fertile F1 hybrids are the conventional productoccur exclusively in Africa. defining a crop’s wild ancestor (Harlan 1992). Chro-

There are two sections of Sesamum found only in mosome pairing takes place more readily if both theIndia. One of these comprises plants with a prostrate crop and its progenitor have the same diploid chromo-habit, S. laciniatum Klein ex Willd. and S. prostratum some number. Reviews of early cytological work andRetz. Another Indian section includes a plant original- attempts to make interspecific crosses amongly named S. malabaricum Burm. (Burmann 1769), Sesamum species were published by Joshi (1961),with an erect habit and a deeply purple hue, known Khidir (1962), Nayar and Mehra (1970), and Mann-locally as the ‘wild gingelly of Malabar’. It was ing (1991).placed in S. orientale as var. malabaricum Nar. byJohn et al. (1950); and described again as S. Progenitor and Progenymulayanum Nair (1963), because he was unaware ofthe previous designation (Nair and Jones 1979, per- The group of wild as well as weedy forms native tosonal communication). The earlier name, S. India, described as S. malabaricum (Burmann 1769;malabaricum, is retained here. John et al. 1950) display close morphological, genetic

and phytochemical affinities to a section of the IndianDistinguishing Domestication from Cultivation sesame lines in the collection that we studied mor-

phologically (Bedigian 1984; Bedigian et al. 1986).Some writers, who endorse an African origin of They are bicarpellate, have an open branching pattern,sesame, call upon its primitive cultivation there. In- deeply dissected or divided basal leaves with dentatedeed, a modest and widely scattered literature attests margins, and a markedly purple color tinting the(Burkill 1997; Busson 1965; Dalziel 1955; Peyre de leaves, the stem, the petioles and the corolla. ThisFabregues and Lebrun 1976; Uphof 1968; Watt and distinctive purple form of sesame is found in IndiaBreyer-Brandwijk 1962; Weiss 1983, 2000) that other nearest the center of origin, adhering to the Vavilovspecies of Sesamum and its close relative, effect, postulating that the variation remains closer toCeratotheca sesamoides Endl. are cultivated in Af- the wild type, and more dominant genes are expressedrica, where they are used for their seeds as well as for near the center of origin (Harlan 1995). Farther fromtheir leaves. Because the genus is versatile in this the center more recessive genes are expressed.way, it might confound the issue. It is understandable It should be noted that many wild species ofthat people living in Africa, sometimes facing drought Sesamum, including S. malabaricum, contain chemi-and famine would seek out wild relatives having cal inhibitors and consequently the seeds are difficultphysical resemblance to the sesame crop as a food to germinate. After considerable effort, Bedigiansource during adversity. Thus reports of sesame and eventually succeeded (1984).its wild relatives in cultivation should also be scrutin-ized to determine which plant part is used. Interspecific Crosses and Molecular studies

It is essential to distinguish between domestication indicate Domestication on the Indian subcontinentand cultivation events in defining a crop’s progenitor.A genetic response must take place in order to say a Bedigian (1984) made numerous experimental cross-plant is domesticated (Harlan 1992). While domesti- es between S. orientale and the Indian taxon S.cation is a process of genetic manipulation through malabaricum. Both taxa have the same diploid chro-human activity, cultivation consists of those activities mosome number. Morinaga et al. (1929) were the firstconcerned with caring for the plants. Wild plants, too, to report the diploid chromosome number of sesamecan be cultivated, or tended, involving activities such as 2n 5 26. John et al. (1950) reported that theas tilling the soil, preparing the seedbed, weeding, chromosome number for wild gingelly, S.protecting, watering and manuring. malabaricum is 2n 5 26. The close relationship

between the cultivated plant and this Indian wildFundamental Genetic Evidence relative is suggested in the rank and name selected by

John et al. (1950).A crop’s origin is determined by genetic proximity The taxa S. malabaricum and S. orientale crossed

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very readily, and produced fertile hybrids (Bedigian Fifty cultivars of sesame from different geographic1984, 1988, 1998, 2000; Bedigian et al. 1985, 1986). regions of the world showed no differences in sesaminResearchers in India, most recently Hiremath and and sesamolin content. All samples possessed bothPatil (1999), confirmed these results with reciprocal lignans. As no lines of sesame contained sesamol, acrosses and cytology, and Bhat et al. (1999) and hydrolysis product of sesamolin, it did not appear that(Nanthakumar et al. 2000) used RAPD markers to our procedure was accompanied by hydrolytic degra-demonstrate their proximity. These results support the dation.conclusions previously reported by Bedigian, and Among other species in the genus, there are someshould settle once and for all, the puzzle of sesame’s major differences. Not every species of Sesamumprogenitor, as far as currently available techniques contains both lignans. Some species contain both,allow us to determine it. The taxa S. orientale and S. some contain only one, and some species containmalabaricum clearly belong in one biological species, none (see (Table 1). Sesamin and sesamolin wereand may be distinguished with subspecific ranks. found in seed oils of S. angolense Welw., S. angus-

tifolium (Oliv.) Engl., S. calycinum Welw., S.Supporting Evidence for Domestication on Indian malabaricum, S. orientale, and a weedy escape fromsubcontinent: Lignans Australia. However, S. latifolium Gillett and S.

radiatum Schum. and Thonn. seeds contain onlyPlants in the genus Sesamum produce unique chemi- sesamin, not sesamolin.cal constituents not found in other edible oils that Surprisingly, both sesamin and sesamolin wereenable sesame oil to resist oxidative rancidity. This absent from fresh seed of Sesamum alatum Thonn., S.fact might contribute to its reputation as high quality capense Burm. and S. triphyllum Welw. ex Asch. Thisoil, earning sesame the label ‘‘Queen of the oilseed is significant because these species share other mor-crops’’ (Al-Yemeni et al. 2000; Bedigian 2000; Eckey phological similarities: a capsule with tapering1954). These compounds, sesamin and sesamolin, pointed beak and paper-thin walls, and within thebelong to a category of phenylpropanoid lignans, that genus, only these species have winged seeds. Theyoccur in few other plant groups. were placed in a separate section, Sesamopteris, in

A number of different cultivars of Sesamum orien- recognition of these differences (Bentham andtale, and other species in the genus, were evaluated to Hooker 1873–1876; Engler 1895; Stapf 1906). Usinglearn more about phylogenetic relationships of sesame an even more sensitive method, two-dimensionalwithin the Pedaliaceae and to learn the extent to which chromatography, Salih (1993) corroboratedsesamin and sesamolin occur in related taxa. Neigh- Bedigian’s findings.boring species, genera and families were examined Bedigian (1984, 1988) and colleagues (Bedigian et(Bedigian 1984, 1988; Bedigian et al. 1985). al. 1985, 1986) provide decisive evidence to support

Table 1. Lignans of Sesamum species.

Species Sesamin Sesamolin Seed

Sesamum alatum Thonn. no no fS. angolense Welw. yes yes hS. angustifolium (Oliv.) Engl. yes yes fS. calycinum Welw. yes yes hS. capense Burm. no trace hS. latifolium Gillett yes no fS. orientale L. yes yes fS. orientale L. weedy escape Australia yes yes fS. malabaricum Nar. yes yes fS. pedaloides Welw. ex. Hiern trace no hS. radiatum Schum. & Thonn. yes no fS. rigidum Peyr. ssp.merenskyanum Ihlenf. & Seidenst. no no hS. triphyllum Welw. ex Asch. no no hCeratotheca sesamoides Engl. yes trace f

Whenever possible, fresh seed were used for these analyses. If fresh seed was not available, material was removed from herbarium specimensheld at the Missouri Botanical Garden, with permission. Fresh seed 5 f. Herbarium material 5 h.

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the claim that domesticated sesame arose from a forms of S. malabaricum exist in India today. Theprogenitor on the Indian subcontinent. Its origin was plant is often seen in waste ground and along railroaddetermined by these factors: a wild progenitor in- tracks in south India. At the Aarey Milk Colony ondigenous to the Indian subcontinent; reciprocal cross- the outskirts of Bombay, one can find profusees producing fully fertile F1 progeny; diploid chromo- colonies of this taxon, dubbed a ‘hybrid swarm’ (T.some numbers 2n 5 26 shared by progenitor and Hymowitz, personal communication). But it alsodomesticate; and chemical resemblance: both contain grows in undeniably wild habitats, far from cultiva-the lignans sesamin and sesamolin. tion. Both Harlan and Bedigian took painstaking

precautions to ensure that the seed used for theMuddle of the Literature: Reports about reciprocal crosses were collected from an indisputablyDomestication in Africa wild location, and that the source was a truly wild

relative, not merely a feral derivative of the crop.A proposal by botanists Ihlenfeldt and Grabow- The type specimen described by Nair (1963) wasSeidensticker (1979) declares that S. latifolium Gillett collected at Kanana (Dadri) in Mahendragarh District,is very probably the wild ancestor of cultivated Punjab State, in North India. He reports additionalsesame, simply because it is a wild sesame in Africa. collections from Rajasthan and Uttar Pradesh. On theThis claim is questionable. No experimental evidence other hand, John et al. (1950) put locations from thesupports their assertion; genetic crosses were not Western Ghats along the Malabar coast of Southattempted. It would seem likely to be a genetic India, into the picture. They report that the earliestmismatch, because Ihlenfeldt and Grabow-Seiden- specimen of the variety in the Madras Herbariumsticker (1979) reported that the chromosome number (Coimbatore) was collected in 1884 at Trichur (Coch-of S. latifolium is 2n 5 32, whereas sesame has 2n 5 in). Subsequent collections were made in 1900 at26 (Morinaga et al. 1929). Innumerable attempts to Sullia in S. Kanara, Ichipalle Reserve Forest inmake reciprocal crosses with S. latifolium have failed. Coimbatore District, in 1924, and Walayar, Malabar,Sudanese breeders (M. Hassan, personal communica- in 1929. They stated that ‘‘its habitat extends fromtion; Khidir 1962; M.A. Mahmoud, personal com- Malabar to parts of Bombay and the Central Pro-munication) have tried, over a period of at least four vinces.’’decades. Bedigian (1984) obtained only a few The habit and habitat preferences of the taxon varyshriveled seed. considerably. This author has observed S.

During the past decade a series of review articles malabaricum growing as a slender, unbranched weedhave summarized work about sesame domestication, under 30 cm ht, among coconut trees, on very dryin prominent, highly respected publications (Ashri sandy soils, at the Central Plantation Crop Research1989; Ashri’s 1998; Nayar 1995; Weiss 2000; Weiss Institute in Kayankulam, Kerala [South India]. On theand de la Cruz 2001). Each of these reviews omitted, other hand it grows as a robust roadside weed, with aor inaccurately represented, published work relevant thick (3 cm) stem, reaching a height of 2 m, and withto their subject, thereby perpetuating incorrect in- 16 or more branches, in the rich loam of fallow fields,formation in successive reports. Each author proposed enroute to Mt. Sinhagad, near Poona. One characteror conjectured sesame domestication in Africa, sup- that seems not to vary is the very deep purple colora-ported by the fact that most wild Sesamum species are tion on the lower, elongated lip of the corolla.endemic there. Nayar (1995) wrote: ‘‘The identity of A character that may be used to differentiate thethe species ancestral to sesame is a matter of pure wild and weedy forms is capsule durability. Weedyspeculation; very little work has been carried out on material, such as that collected on Delhi ridge, hadthis aspect.’’ Ashri’s consideration (1998) omitted a capsules that were significantly thicker, with persis-publication directly related to his discussions about tent woody walls, and were more difficult to breakclassification and germplasm resources: Patterns of apart than the thinner-walled capsules of the wildMorphological Variation in Sesamum indicum, form.(Bedigian et al. 1986). Despite numerous assertions,no proper evidence has ever been presented in the Breaking the rules: Dynamics of Domestication incase for African domestication. Sesame

Nayar raised a legitimate concern that the taxon S.malabaricum investigated may be a weedy escape of Sesame does not conform to the usual rules that definecultivated sesame. It is true that wild as well as weedy domesticated seed crops (Harlan 1992). The seed size

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of sesame remains virtually unchanged, although seed habit allows the crop to continue to produce for up tocolor does change, and the capsules remain partially 180 days. Thus its indeterminate habit is favorabledehiscent. Harlan (1995) speculates that this derives because it increases the yield and crop security.from traditional harvest methods. Ashri and Ladi- Harvest methods already described permit all seeds tojinski (1964) also observed this deviation: ‘‘One of be harvested at once at physiological maturity.the most important steps in the domestication of our Hence we see that sesame, under domestication,crop plants which are grown for their seeds has been has retained three traits generally associated with wildthe loss of seed dispersal mechanisms. This has plants: shattering of seeds, indeterminate growth andoccurred in all but a few of them. Yet for sesame, long, late maturity. The long maturation is not detri-which has been grown extensively since ancient mental to the crop, which is adapted to the cycle oftimes, there were no indehiscent types before 1943, rains and balanced by photoperiod. The Nuba Moun-when Langham discovered an indehiscent plant and tains region has two sets of rains. The first occur infound that the trait was controlled by one pair of May/June, during germination and seedling establish-alleles’’... ‘‘indehiscence is recessive.’’ ment, followed by a few weeks of dry weather. This

The context in which the domestication of sesame cycle is suited to the growth requirements of the plant,has occurred may give some perspective about the since sesame seedlings cannot tolerate waterlogging.reasons for this nonconformity. Sesame is a ‘poor Once the plants are past seedling stage, the long rainsman’s crop’. As a crop of primarily underdeveloped occur. They cease by early November, and harvest innations where subsistence agriculture generally still the region does not begin until December, hence theprevails, selection pressures were those that met the spacing is sufficient for adequate maturity.requirements of the growers and domesticators. In contrast, sesame does respond with loss of seedDomestication is the result of selection pressures dormancy, and in this way it behaves like aassociated with harvesting and sowing, and harvesting stereotypic domesticated plant. Other changes in theusually leads to the loss of natural mechanisms of crop that distinguish it from near wild relatives areseed dispersal (de Wet 1979). However, in the case of seed and capsule characters. Since the seeds are thesesame, different selection pressures were in effect. objects of interest, it makes sense that these are theThe cultivators adapted their harvest strategies to the prime focus of modification.plant’s habits: when the stem and capsules have Seeds of domesticated sesame are generallyturned yellow, but before they have opened, branches smooth, not rough-textured, higher in oil and display aare cut and bundles of branches are left to dry in the diverse array of colors: white, beige, rust, brown andfield, standing upright. An ecological factor of impor- black, possibly reflecting regional folk preferences.tance here is the reliability of a dry period, or the To increase the yield, selection has favored larger sizeentire harvest would be ruined. After approximately capsules. One cultivar in Sudan, ‘Dinderawi’ growntwo weeks, the thoroughly dried capsule branches are in the Eastern Nuba Mountains, has capsules over 5inverted onto a large sheet and the seeds are collected. cm long, with abundant gray seeds.

Another principle of crop evolution is that selection Other genetic modifications for increased seedunder domestication favors uniform population as yield are tetracarpellate capsules, potentially enlarg-well as uniform maturity (de Wet 1979). Mechanized ing the space for more seeds to fit, and a structuralfarming increases the homogeneity of crop plants. But modification that converted the two extrafloral nec-under a regime of ‘‘primitive or nonmechanized hus- taries to capsules. The nectaries are rudimentarybandry, the soil is prepared over a long period of time, flowers, which are genetically modified to producethe planting is a long, drawn out affair, and harvest flowers and capsules, increasing the number of cap-extends over a long period. Thus mixed populations sules per node from a single one, to two or three. Thisare favored, and selection pressure is somewhat in particular modification of restoring fertility to thefavor of variant types’’ (Harlan 1951). Bedigian nectaries seems to be a regional one, seen mostly inobserved this repeatedly, in the isolated southern lines from China and Japan, and breeder’s materials.Nuba Mountains of the Sudan (Bedigian and Harlan Although additional capsules and tetracarpellate cap-1983). sules occasionally occur in local material in Sudan

Yet another general rule regarding the dynamics of and northern Uganda, it appears that East Asiandomestication is that long term maturity has selective breeders carried out intensive selection for this trait.value for wild plants but is detrimental to cultivated Selection for oil content is another important criter-races (Harlan 1992). Sesame’s indeterminate growth ion. This author finds that a single human population

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may select two or more different varieties for different the crop provides more opportunity for farmers touses. The Nuba peoples have intentionally selected select and develop variant forms and local varieties’’larger-seeded, bitter types, high in oil, as well as (Harlan 1951).smaller-seeded ‘‘sweet’’ landraces, that have different The sesame crop has certainly undergone furtherplant habits, seed colors, sizes, and maturity dates. modification outside its original center. BedigianWeiss (1971) reported that the highest oil content is observed clusters of diverse forms, quite distinct frompresent in Mediterranean material, with Far-Eastern each other, amongst the collections from Turkey,cultivars being the lowest. African types are late- Sudan, India and Japan/China (Bedigian et al. 1986).season, with above average oil content. This might be due to the fact that the crop was

domesticated long ago, and after seeds were tradedHow did Sesamum get to the Indian subcontinent? from the original center, the distinct cultivators who

obtained them and the broadening of their newIt is possible that the genus Sesamum arrived on the habitats resulted in further alteration. ‘‘It is extremelyIndian subcontinent at a very early period, before difficult, if not impossible, to sort out variation pat-Gondwanaland broke apart, transferring sections of terns derived from long and complex histories fromthe genus to India. There, it was probably domesti- those generated by repeated domestications’’, (Harlancated late, somewhat after the introduction of ‘‘foun- 1976).der’’ crops. Diamond (1999) suggests that ‘‘local Landrace populations are variable in appearancedomestication followed the arrival of founder crops (Harlan 1970, 1992). The Nuba Mountains regionfrom elsewhere’’: i.e. crops such as wheat, barley, contained, within a small area, considerable diversitylentil and pea. He wrote: ‘‘Those imported domesti- and allowed detailed analysis of these principlescates may be thought of as ‘‘founder’’ crops because within a culturally and geographically isolated loca-they founded local food production. Only later did tion (Bedigian and Harlan 1983). The Nuba Moun-domesticates derived from indigenous species of the tains are a classic example of a secondary center ofIndian subcontinent, such as humped cattle and diversity (Bedigian and Harlan 1983). There is greatsesame, appear in Indus farming communities.’’ variation in plant morphology, seed color, and maturi-

Alternatively, it might be that sesame represents an ty date: in dry areas of North Kordofan a commonexample of transdomestication (Hymowitz 1972), cultivar, ‘Hirehir’, matures in 70 days, while on thedefined as the movement by man of a wild species clay plains, farther south, cultivars require 150–180from its indigenous area to another region where it days.subsequently is domesticated. His example is guar Throughout the Nyala area there is a late-maturing,(Cyamopsis tetragonolobus), of which the three near- robust, dark seeded cultivar, with numerous, wideest species are all African, yet the crop appears to branches, that tolerates the intense sunshine and heathave been domesticated in India and Pakistan. Unlike at the fringes of the Sahara, grown by subsistencethe case of guar however, the evidence in India for millet cultivators throughout the region. The Gedarefsesame use in antiquity is based not only on the region is famous for a different late-maturing, uni-retention and current use of modified forms of the form sesame genotype, grown primarily for export.ancient name ‘‘til’’, but on archaeological remains Many Turkish cultivars in our trials matured early,(Allchin 1969; Bedigian 1984, 1985, 1998, 2000; too, although this was not universally true (BedigianBedigian and Harlan 1986; Fuller 2000; Fuller and 1984; Bedigian et al. 1986). Most early-maturingMadella 2000; Kajale 1991; Kenoyer 1991; Possehl landraces were collected from coastal regions of1997, 1998; Vats 1940; Weber 1991). Turkey. It may be that the intense summer heat and

lack of moisture there encouraged selection for earlymaturing cultivars, before dessication would deprive

Diversity farmers of their harvest.Examination of more than 1000 accessions of

Our studies revealed an enormous amount of local sesame shows that Korean and Indian cultivars arevariation in domesticated sesame (Bedigian 1984; distinctly dissimilar in morphology (Bedigian et al.Bedigian et al. 1986), an observation backed by other 1986). Many Indian forms show a rich purplish hue,scientists (Brar and Ahuja 1979). Variation is en- 3–5 foliate, deeply divided basal leaves with dentatehanced by widespread cultivation: ‘‘Local interest in margins, flowers that are intensely pigmented, and

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express dominant genetic characteristics (Harlan is mandated to study sesame. See also Ashri (1989).1995). Korean cultivars have an overall light green The International Plant Genetic Resources Instituteplant color, pure white flowers, and lance-shaped recently selected a list of crops to examine for theirstrap leaves with entire margins. publication series: Promoting the Conservation and

Use of Underutilized and Neglected Crops, butsesame was removed from the original list. Yet

Genetic Resources Alert Sesamum is a major commodity in many Africancountries, in much of the Southwest Asia, India,

The study carried out by this author in Sudan during China, Japan, Korea and Mexico.1979–80, resulting in a collection deposited with the Clearly, sesame research is seriously overlooked.USDA could not be obtained again today. The war in Most of its growers and advocates are members ofthe Sudan during the past decades has destroyed many poor nations, and perhaps thus attract few researchers.Nuba fields and crops. The germplasm nursery at The danger is that with habitat loss and geneticKadugli, that Bedigian reviewed, is gone. The Nuba erosion, out-migration from rural areas to urban, andcultural life this author documented (Bedigian and adoption of ‘new crops’, both the cultivators and theirHarlan 1983) is also in ruins. Many Nuba sesame agricultural practices are rapidly disappearing. Effortsgrowers have fled the region. The results are lost to preserve a portrait of the long-established use ofdiversity of their unique sesame cultivars, just as war sesame can help fill this research gap.elsewhere in Africa resulted in lost crop geneticresources (Richards and Ruivenkamp 1997). This isone example of world events that urgently mandates Acknowledgementsfurther analysis of these collections. Ashri’s (1998)point is alarmingly correct: ‘‘Special efforts are This report is dedicated to Jack R. Harlan, a scholar ofneeded to improve germplasm resources. These in- the highest integrity, who encouraged his students byclude closing gaps in collections, establishment of his example, to be adventurous, and explore thorough-core collections, evaluation and documentation of ly. A gentle and generous role model, his lifetime’saccessions.’’. investigation of plant genetic resources and plant

Ashri called for more extensive collection of wild introductions has enhanced our specialty.Nine monthsspecies and study of interspecific relations. Fully of fieldwork in Africa between June 1999 and Januaryconscious of that need, Bedigian spent nine months in 2001, and two months of herbarium study in EuropeAfrica (1999–2001) studying and collecting wild was supported by the National Geographic SocietySesamum species, and is preparing to undertake the Research and Exploration Grant [6218–98. Theanalyses that must follow. Antioch College Knight Foundation Grant for Indi-

vidual Faculty Travel Abroad in 1994, an AntiochCollege Faculty Development Award in 1994 and a

Prospects Knight Foundation Grant for Course Development in1993 funded portions of my research. Herbarium

Sesame is a crop of great importance, particularly to analysis enriched my study. Appreciation is extendedAfrican and Asian farmers. It presents a special case to each of the keepers for access to their collections.because of its dual use as leafy vegetable and seed The following herbaria were consulted to create acrop. It is a readily available source of nourishment database of Sesamum species: Africa: Nationalduring famine or hardship. Latham (1965) noted that Museum, Nairobi [EA]; University of Khartoumits ‘‘dark green leaves are rich sources of carotene, [KRT]; Makerere University, Kampala [MAK]; Uni-ascorbic acid, iron and calcium; they contain useful versity of Dar es Salaam [UD]. Europe: Nationalquantities of protein and it is highly desirable that Botanic Garden of Belgium at Meise [BR] and Uni-

´rural peoples continue to eat them’’. The leaves may versite Libre de Bruxelles [BRLU]; University ofbe dried and stored for use during food scarcity, Coimbra [COI]; University of Lisbon [LISU]; Institut

¨another distinct advantage. fur Allgemeine Botanik, Hamburg [HBG]; BotanicalParadoxically, despite its nutritional value and its Garden, Munich [M]; Royal Botanic Gardens, Kew

´ ´historic and cultural importance, research on [K]; Laboratoire de Phanerogamie, Musee NationaleSesamum is scarce. No international CGIAR agency d’Histoire Naturelle, Paris [P]; Nationaal Herbarium

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Bentham G. and Hooker J.D. 1873–1876. Pedalineae GeneraNederland, Wageningen University branch [WAG].Plantarum. Reeve and Co., London, 2: 1054–1060.US: Harvard University [HUH]; Missouri Botanical

Bhat K.V., Babrekar P.P. and Lakhanpaul S. 1999. Study of geneticGarden [MO]; University of California, Berkeleydiversity in Indian and exotic sesame (Sesamum indicum L.)

[UCB]; Smithsonian Institution in Washington, DC germplasm using random amplified polymorphic DNA (RAPD)[US].The staff of various libraries gave prompt assis- markers. Euphytica 110: 21–33.tance in finding literature that was frequently difficult Brar G. and Ahuja K.L. 1979. Sesame. Its culture, genetics,

breeding and biochemistry. Annual Reviews of Plant Sciences 1:to locate: the Library of the University of Illinois, the245–313.Library of the Missouri Botanical Garden, and the

Burkill I.H. 1953. Habits of man and the origins of the cultivatedOlive Kettering Library, Antioch College.plants of the Old World. Linnaean Society Proceedings, London.

Burkill H.M. 1997. The useful plants of West Tropical Africa. 2ndedn. RBG Kew, 4: 414–422.

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Al-Yemeni M.N., Hussain M.A. and Basahy A.Y. 2000. Mineral to the Flora of West Tropical Africa. In: Hutchinson J. andcomposition of some sesame seeds (Sesamum indicum L.) grown Dalziel J.M. (eds), 2nd reprint edition. Crown Agents for Over-in the Gizan area of Saudi Arabia. Phyton (Buenos Aires) 67: seas Governments and Administrations, London.121–125. Darlington C.D. 1963. Chromosome Botany and the Origins of

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