S. Afr. J. Bot. 1997, 63(4) 185- 190 185

Fonio : Ethnobotany, Genetic Diversity and Evolution

K. W. Hilu*', K. M'Ribu2, H. Liang', and C. Mandelbaum3 ' Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg, Va. 24061, USA 2Kenya Methodist University, PO. Box 267. Meru, Kenya 3Department of Botany, University of Texas, Auslin, TX 78713

Rec;eived 27 Dec.:ember 1996: revised 2 April 1997

Tr ue tonio ( exilis (Kipp.) Stapf) and black (D. iburua Stapf) are two domesticated minets of . These are used as food and fodder as well as in brewing. They are persistent crops that do not require careful cultivation, and thrive under a rang e of difficult agricultural conditions. Fonla millets are amongst the least studied crops, and there has been no study on the genetic diversity and evo lution of these two millets. Random Amplified Polymorphic DNA (RAPD) approach was used in this study to assess the genetic diversity in tonio millets and to evaluate proposed hypotheses on their presumed wild progenitors. The results point to a very high genetic diversity in true fonio and to the possibility of multiple orland strong ecological or agricultural differentiation. The genetic diversity in black tonio could not be assessed because of the availability 01 only one accession for the crop. The molecular data substantiate previous hypotheses that point 10 the morphologically allied species D. longiflora (Halz) Pers. and D. temata (A. Rich.) Stapf as possible progenitors of true and black tonios, respective ly, and do not support the proposed genetic affinities between D. fuscescens (Presl) Henr. and true fonio. The study underscores the need for concerted eHort to collect and conserve genetic resources of 10nio millets and their wild progenitors since they are poorly represented in world gene banks.

Key words: Fonlo millets, Digitaria, RAPO, evolution, genetic diversity, ethnobotany.

'To whom corres pondence should be addressed.

Introduction Ethnobotanical overview of Ionia millets Millets; small- cereals belonging lO differem grass genera; 1\vo of the about 230 species of the cosmopolitan genus Digi-' rank 14 among the 30 leading crops that feed the world (Hilu taria (Clayton & Rcnvoize 1986) are domesticated millets of 1994a). Although millets represent a small portion of the total west Africa: D. exit;s (Kipp.) Stapf and D. iburua Stapf. Digi­ world food production. they are crops of local importance in taria exi/is is commonly known as fonio, true fonio, or hungry . It is only known from western Africa, where it has been cul­ semi~arid regions of the world. They provide reliable yield in low tivated throughout the Savan na zone fro m to Lake ra infall areas (Dogget 1989), especiall y in drought-plagued parts (Lewicki 1974; Porte res 1976; Pu"eglove 1972). Fonio is a of Africa and India. Millets also provide an in~xp e nsive source of morphologically very variable crop in which numerous botanical nutrition for rural peoples (Rao 1(89). Nutritional studies of fin­ varieties have been recognized (Portercs 1955). Harris (1976) ger and barnyard millet (Malleshi 1989; Barbaeu & Hilu noted that the greatest varietal diversity of fonio occurs in the 1993; Mandelbaum et a/. 1995) have demonstrated their comp~t ­ region of the Fouta Djallon plateau and in the valley of the upper iii veness with, or even superiority to, the more commonly con­ and , and Porteres ( 1976) noticed that the number sumed such as and rice. For instance, Barbacu & of varieties decrease sharply eastwards towards Chad. The cu lti­ Hi lu (1993) reported that the calcium content of finger millet was vation of the crop covers approximarely 721,000 acres annually, 63 times that of corn meal and about 12 ti mes thal of brown rice and during the ecologically most difficult months fonio suppli es food to 3-4 million people (Porteres 1976). Fonio is a staple crop and flour wheat. Furlhermore, millets provide quality fodder of on the Fonta-Djallon in and the Bauchi Plateau in excellent nu tritional value. Thus, these cereal crops have the (Purseglove 1972). This millet, although not a staple crop in the potential to playa larger fUlure role in world agriculture. espe­ Sudanic zone, is widely grown there as a complementary cereal cially with the predicted glohal warming and its consequent where the rai nfall exceeds 400 mm (Purseglove 1972). Digitaria droughts. Both basic and applied research on millets is needed exi/is, as well as D. iblfrtla, are sown during Mayor June and for the improvement of their agronomic traits. harvested in September (de Wet 1989). Fonio millets are amongst the least studied cereal crops in gen­ True fonio is known for its short growing season that ra nges eral and millets in particular. There has been no study focusing from 40 days to three and a half months. This agronomic on the genetic diversity and evolution of these two millets. Eval­ attribute is probably due to the quick germination (3-4 days after uation of genetic djversily of crops and determination of their sowing) and the early rapid growth (Purseglove 1972). Among gene pools represent basic and valuable practical information in the large number of varieties grown by the Temne and other nonhern tribes in 'sierra Leone, long and short season cultivars their breeding programs. In this paper the Random Ampli fied are recognized and are known as Pa-sacUl (longer season culti­ Polymorphic DNA (RAPD) approach is used to assess th e vars) and Apeilldei-pufundf (short season cultivars). Fonio is a genetic diversity in fonio millets and to evaluate proposed persistent crop that does not require careful cultivation. and its hypotheses on the presumed wild progenitor of these crops. This varieties thrive under a range of difficult agricultural conditions, paper is one in a series of papers that focus on genetic diversity including sterile or unproductive soils. difficult terrains, and and gene pools of millets (Hilu I 994b, 1995; M'Ribu & Hilu waler stress (Lewicki 1974; Porteres 1976; Purseglove 1972). In 1994.1996). addition, herbarium collections cX;:lInined indicated that the crop 186 S. Ali 1. Bot. 1997, 63(4) grows on shallow sandy soil in open grass, forest, and savanna proposed D. barbillodis Henr. as species closely allied to black COIll I1l Un ilies. fonio. Digitaria barbillodis, although overlaping in geographical Several local names exist for true fonio millet. It is known as distribution with both fonio millets. differs morphologically from jimdi, jOllde, and find; in WalDr; Pelle in the language of the black Fonio in several characters such as the shape or the rachis, Sierra Leone.! Temnc: allsi in the Songhai language; achcha or the relative length of the upper glume to th e lemma, and the atc}w in the Hausa areas of the Nigeria (Lewicki 1974); kputi in number of nerves on the glume (Clayton 1972). the Mender and kpeindei in the Temne. Porteres (1955) studied the common appellations of Fonia in detail and found out that Material and Methods these names can be generally translated as 'things to eat' or Plalll material: Twt::l ve coll ections for true [on io (D. exitis). one col­ 'foods'. Dixitaria exilis also has the common name ' hungry lecti on each for bl ac k fonio (0. ibIII'UCI), D. iongijlom, D. lemala, rke', however, Harlan (1977) indicated that th e grain is fre­ and D. juscescens (Presl) Hem. were examined for th e RAPD study. quentl y grown as a dt!licacy food. The grains are made into cous­ Table 1 lists the access ions used, their area of origi n and the sources l:OUS, boiled like rice either alone or used in stews, ground into a of material. The representation of the species in this study was !lour which is caten as gruel seasoned with butter or fat, and used constrained by the scarcity of the collections for these crops and in brewing. In the Niger, the seeds are used as a delicacy where their related wild species in the vari ous world germ plasm banks. [hey arc ground and made into a sauce. True fonio is also used as Collecti ons for true fonio werc limited in geographi c origin and fodde r, mixed with building clay, and in some areas of Africa uti­ found in the International Livestock Center for Africa (lLCA) germ­ lized for ceremonial purposes (Clark 1976; Dalziel 1937). plasm bank only. Similarly, there was only one coll ection available The first mention of fonio was in the geographical work of for each of the other four species in the germpJasm banks. For the AI-Omari, who wrote of West Africa from 1342-1349 (Lewicki ethnobotanical and morphological aspects of the study, herbarium 1974). AI -Omari reported that fonio is one of the basic fo ods in specimens for the above species were examined from the herbaria of the western Sudanic region of Africa (Porteres 1976). Another the Royal Botanical Garden, Kew, England and the Natural Hi story report of the cultivation and use of foni o comes from Ibn Batula Museum in Paris. ( 1353-1354), whn tells of local peoples se lling the grain to trave­ lers in (Porteres 1976). However, the domestication of the DNA isolation: were grown from seeds in the greenhouse crop is more ancie nt. Munson (1976) suggested that fonio was and leaf samples were harvested fro m fou r-week old plants and stored at _80°e. Total cellular DNA was isolated from leaf material domes ticated around the headwaters of the Niger Ri ver, at of a single individual plant rollowing M'Ribu & Hilu (1996). We around 4500 B.C. (Murdock 1959). The names for fonio come from linguistic groups originating from the middle Niger and Scnegalic arcas, providing evidence for its domestication in the Table 1 Species, accessions, sources of material, and vicinity of the central Nigerian delta (Porteres 1976). The ances­ geographic origin of the material used in the study. For tral species of is not conclusive ly known. The uniformity of labeling, the collection numbers of the sen­ closest wild relative of {rue fonio is (Hatz) ior author (KH) were used throughout. Digitaria exilis Pel's., which grows in hot regions throughout Africa and Asia accession NIAR 27737 of South Africa is marked as (Harlan 1992). Digitariafuscescells (Presl) Henr., a species mor­ Gambia MI671125 cultivar which implies a possible origin phologically related to D. longij1ora, has also been proposed as a from Gambia possible putative ancestor for true ronio (Porteres J 955). The other domesticated species, Digitaria ibuTlw (black Species Accessions Source of material Geogrnphic origin [onio). is cultivated by the Hausa tribe and by the Pagans on the D. exit;.t KH2730 alLCA 156 10 l os plateau of Nigeria, in the Alacora Mountains of Dahomey, in Guinea. Cameroun, and Zaire (Dalzie11937; de Wet 1989; Harris D. exilis KH2734 ILCA I5615 Togo 1976; this study). The name is derived from the dark color of the O. exitis KH 2735 ILCA I5617 Togo spikelet. This millet is considered as the principal grain crop for the Pagan people. Being cultivated between 400 and 1300 m, D. exilis KH2736 ILCAI561g Togo black foni o is considered to be a sub-alpine plant (Porteres D. exil;s KH 2738 ILCA 15620 Togo 1976). Black fonio is often found in cultivation wi th true fonio. and is frequently planted between rows of and pearl D. exilis KH 2740 ILCA I5622 Togo millet (Porleres 1976; de Wet 1989). The crop is drought tolerant D. exi/i.t KH 2741 ILCA)5624 Togo and offen yields a harvest when the major cereal it accompanies fail s to survive (de Wet 1989). It is used to prepart': a D. exil;J KH 2742 ILCA I5625 Togo called Wusu -WIISU in parts of western Africa; however. difficulty D. exitis KH2743 ILCAI5627 Togo in re moving the chaff of black fonio gives true fonio an edge over black fon io as a food crop in that region (Porteres 1946, 1976). D. exi/i.f KH 2745 ' NIAR27737 Soulh Afri ca Black foni o is typically grown as a grain, making the bever­ D. ibuT/w KH2760 'P1238288 Nigeria age known as Tchaplllo (Harris 1976; Porteres 1976). Like true t'onio, bl ack fonio has no traces in the archeological D. lllngijlora KH2770 P1 364523 South Africa records to ve rify its area of domestication, but is considered an D. remota KH2800 PT29984I South Africa endemic of West Africa (Harlan 1992). Black fonio was first mentioned outside Africa through the reports of Dudgeon in D.JuscescellJ KH2756 PI 196479 Brazil 191 I (Portere s 1976), which mentioned its cultivation in north­ aILCA: collection numbers of the International Livestock Center for ern Nigeria. Portercs (1976) suggests that this cereal was first Africa domesticated in Northern Nigeria, whereas Harris (1976) specu­ iatt':s that it may have originated as a cultivated plant in the Air "' PI: Pl an t Introduct ion numbers of the U. S. Department of Agricul­ region of the Southern Sahara. The wild progenitor of the crop is ture Plant Introduction Stations. not known. Stapf (19 15) pointed oul Digiraria lemata (A. Rich.) Stapf as the c losest wild species to D. iburua. Hernard (1950) l: NIAR : Na tionallnstilule of Agrobiologica l Resources of Japan S. Afr. J. Bol. 1997,63(4) 187 found this procedure to be most effective in producing DNA for the Digitaria species and it can be used successfully for amplification by the polymerase chain reaction method. Approxi mately 05 0-100 rug of 0.00 0.25 0.50 lissue was macerated in side a 1.5 ml Eppendorf tube containi ng 300 ).1.1 of eTAB ext raction bu tTer (2% hexadecyltrimethyl-ammoniu m bromide. 0.7 M NaC!, JO mM EDTA. 50 mM Tris- HCI pH 8 and 0. 1% mercaptocthanol). Foll owing maceration, another 300 ).1.1 of buffer was ndded, and the suspension was incubated in a water bath at 60· C for 10 min. The suspension was spun lightly to pellet the plant debris. and the aqueous portion was mi xt!d with an equal vol ­ ume of chloroform and centrifuged for 1 min. The DNA in the aque­ ous phase was precipitated with isopropyl alcohol. pellcted by ccntrifugation, and dissolved in TE buffer (Tris-EDTA, pH 8.0).

DNA wnpiijicmj{J/l and electrophoresis: Eleven 10-base oligonu­ Figure 1 The clustering of the 14 ilccessions that represent D. exi­ cleotide primers (Operon Technologies. primers OPA 2, 3, 5, 9, 10, lis, D. iburua. D. Longiflora. D. temata and D. jllscescells. The ten I 1,1 2, 16, 17. 18, 19) were selected on the basis of their ability to accessions of D. exj/is

Table 3 The similarity matrix of 10 accessions of Digitaria exilis (numbered KH) and 4 accessions belonging to four other species examined in this RAPD study. The similarity values are calculated from the Dice algorithm using the NTSYS-pc computer program

Accessions or species 2 3 4 5 6 7 8 9 10 II 12 13 14

I. KH2745 1.00

2. KH 2730 0.3 1 1.00

3. KH 2742 0.76 0.28 1.00

4. KH 2743 0.35 0.82 0.33 1.00 5. KH2734 0.33 0.80 0.28 0.83 1.00

6. KH2735 0.38 0.81 0.33 0.78 0.82 1.00 7. KH2736 0.34 0.65 0.27 0.69 0.70 0.72 1.00

~. KH2738 0. 33 0.68 0.35 0.63 0.63 0.63 0.6l 1.00

9. KH2740 0.41 0.74 0.37 0.66 0.75 0.70 0.76 0.70 1.00

10. KH2741 0.41 0.70 0.35 0.72 0.77 0.71 0.75 0.72 0.88 1.00

II. D _/ollgiflora 0.36 0.36 0.36 0.29 0.31 0.40 0.67 0.57 0.44 0.40 1.00

12. D_ibura 0.30 0.32 0.35 0.29 0.32 0.30 0.26 0.45 0.34 0.36 0.17 1.00

13. D_Iemata 0.28 0.33 0.29 0.31 0. 33 0.33 0.33 0.38 0.35 0.37 0.00 0.58 1.00

14. DJjI,w.:escells 0. 11 0. 10 0.2 1 0.09 0. 10 0. 11 0.15 0.18 0.00 0.00 0.00 0.27 0.35 1.00

The UPGMA-based phonogram resolved three subelusters that fonio at the genetic level. The ten accessions of the crop dis­ corresponded to I) D. exilis-D. longiflora 2) D. ihurua- D. l e f­ played about 20% variability in the amplified RAPD bands. The lIata, and]) D./llseeseelis (Figure I). The two fonio millets (D. grouping of the ten accessions in two clusters that show resem­ exilis and D. iburlUl ) were very distinct, separated at 0.31 simi­ blance at 0.34 is an indication of genetic differentiation in the larity level. The 10 accessions of true [onia, D. exilis, grouped crop that is either associated with multiple domestication events into two clusters separated at a low similarity (0.34), (Figure I). or a broad genetic diversity associated with selection, possibly One cluster was comprised of a Gambia MI671125 cultivar col­ for different ecological conditions or agricultural practices. This lected fro m South Africa and one of the Togo culti vars. The sec­ finding gains support from the proposed presence of three cent­ ond cluster included the remaining eight accessions as well as the ers of diversity for true fonio in west Africa and the adaptation of wild specit!s D. longijlora; the latter grouped with these true ronio accessions at a si milarity value of 0.43. The black fonio accession grouped with D. lemma at the 0.58 level. Digitaria !lIscescens was last to cluster with the other four wild and domes­ ti cated species of Digiraria (Figure 2). T he three co-ordinates of the pca accounted for 60% of the variation. The pca separated the species and the accessions of D. exilis in a pattern that was supportive of the grouping gener­ aled by the UPGMA clustering method (Figure 2). Digitaria longiflora appeared within the group of eight accessions of true tonio, while the other two true fonio accessions were removed on the second co-ordinate (Figure 2). Similarly black fonio (D. ibu­ nUl ) and D. lernalll appeared in a very close proximity on the three co-ordinates, while D. fuscescens was dishnct, especially on the third co-ordinate. The minimum spanning tree demon­ strated the lack of di stortion in the PCC as neighboring units were first connected prior to their linkage to other groups. The overall pattern of neighbor joining depicted by the MST resem­ bles the clustering pattern obtained by the UPGMA method.

Discussion Harlan (1992) considered true and black fonio millets as endemic crops in his classification of crops according to geographic di stri­ bution. Both are west African, with true fonio grown from Figure 2 The distribution of the accessions of D. exifis, D. iburua, Nigeria to Senegal and black ronio from Nigeria to Togo. The D. IOllgijIora, D. (erna/a and D. fuscescens on the first three axes of limited distribution oftrue fonio, however, is accompanied by an the principal co-ordinate. The minumum spanning tree is mapped on extensive degree of morphological variability (HarriS 1976) and th e principal co-ordinate plot to show the nearest neighbour connec­ by the presence of a considerable number of varieties and culti­ tions. Accession and species labels correspond to those cited in Fig­ vars. The information from RAPD reflected this feature of true ure 1. s. Afr. J. Bot. 1997. 63(4) 189

the different varieties to different ecological conditions (Portercs Digitaria fuscescens is a creeping, up to 20 cm high pbnt with 1976 ). True fo nia is thus ge netically variable, possibly due to paired racemes and protruding grain , wh ile true fonio is an erect, outhrl!ed in g mechan isms. T he level of genetic variabili ty in true 40-80 cm tall plant, wi th 3- 5 raccmt.!s p~ r inflorescem:c and a tonia is high when compared wi th that reported for other millets. grain enclosed within the kmma (Clayton 1972). In contrast. true For instance, similarities in RAPD among proso millet, P(lllicwn fonio resembles D. /ongij/ora in these morphological characters. mil.inceum L., was 0.52-0.9 1 among accessions examined from The hi gh morphological si milarit ies between true foni o and D. Europe, United Kingdom, Asia, and Africa, and was only 0.87 in IOllgifTora parallels the genetic similarities retlected hy th e the Indian and 0.90 in the Iranian coll ections (M'Ribu & Hilu RAPD data. Digitaria longijlora shared up to 67% of the RAPD 1994). In finger millet, [ (L.) Guertn. subsp. bands wi th the domesticated true ronio and clustered wi thin the cO re/calia] . similarities in RAPD among accessions from across accessions of the later. This finding su pports Stapf's hypothesis India and Africa ranged from 0.64 to 0.92 (Hilu 1995). There­ (S tapf 1915) that proposed D. Longiflora as th e putative wild pro­ fore, the range of 0.28-0.88 similarity in true foni o is considera­ genitor fo r true fo nio. The main morphological diffe rence bl y high when the relat ively small region from whi ch the between the two is the pubescence of th e lemma in D. /o llgijfom. accessions ori ginated is considered. Variation in the amount of hairs on the le mmas of D. LOllgiflom The variable DNA bands in the fonio mil lets represent molec­ has been observed in some herbarium specimens and thus the ular markers that can potentiall y be used in identifying cultivars difference in this morphological trail is quali tative and is not sig­ and tagging genetic traits in breeding programs. The RAPD nificant. The morphological si mi larities between the two taxa arc method thus represents a promising approach for studying so hi gh that a number of herbarium specimens of D. /OI zg ij/()ra ge netic variability and genomic relationships in true fonio. Addi­ were mi s-identi fi ed as D. exi/is and some herbarium specimens tional molecular markers can be generated with the use of more contained plant parts of both species. In fact, Stapf (1915) placed primers. In true fonio, variation in RAPD bands is high as it is hoth ta xa in section Verrucipilae wh ich is characterized by the evident from the range of si milarities among accessions (0.28- pubescent spike\ets in spite of the glabrous lemmas of D. exili.... 0.88). Unfortu natel y, detai led background informati on on the ori­ Artifi cial crosses between th e two taxa are needed to confirm the gin of th e accessions is not available to assess the pattern of vari­ chromosome homology ami interfertility between the two taxa. ation at the geographic or population leveL The genetic Also, additional west African species of secti on Verl'll cipi/a(! variability in black fonio could not be assessed because of the might need to be examined 10 exclude al tern at ive hypotheses. presence of onl y one accession for th is millet in the international Stapf (1915) suspected D. temata to be the progenitor of black germplasm collecti ons. This lack of genetic resources for such a foni o on the basis of morphological affi nities. He, however, indi­ potentiall y useful crop in semi- arid regions is a most unfortunate cated that black fon io differs from D. ICrIla{(/ by the crowdeli . situation that needs to be rectifi ed. closely imbricated spike\ets that tend to be quite glahrous and The identification of ancestral species for crop plan ts is an slightly larger. Digitaria (emMa differs from black foni o aLso in important step toward their improve ment because the wild spe­ the presence of dense lines of appressed hairs between the lemma cies is a significant component of the primary gene pool as it nerves. T he two are simil ar in the annual habit and the presencc possesses much higher gt:netic diversity th an the crop (Hilu of a corona of short hairs on the ti p of the pedicel. In this RAPD 1994a, 1995). Unfortonately. there has not been any cytogenetic study, black foni o and D. lemata showed a 0.5R Dict.! similari ty. or molecular study addressi ng the ancestral relationships This va lu e is considerably hi gher th an the Di ce simil arity va lues between th e fonio millets and other Digitnria species. The spe­ obtained between D. fuscescens and either black [onio or D. Ie/'­ cies proposed as possible progenitors for true and black fonios nata. In fact, it is within the range of Dice similarities computed are selected on the basis of morphological similarities. Digittlritl among the accessions of true tonio. Thus, the grouping of D. rer­ IOllgiflora has been proposed on the basis of morphological affin­ nata wi th black fonio presents new cvidencl:! in support of th e ities as a possible ancestral species for true fonio (Dalziel 1937; possible origin of black fonio from this wild species as proposed Stapf 19 15). Stapf ( 19 15) indicated that D. exifis approaches D. by Stapf (191 5). However, cytogeneti c studies of these species longij1ora very c losely, differing from it mainly by the com­ and the exploration of other D ig itarhl species native to the are" pletely glabrous and somewhat more 'turgid' spikelet. In addi ­ of domestication of this mi llet. especially D. barbillodes, are tion to D. /ollgijfom, Henrard ( 1950) proposed D. jllscescens as needed for a conclusive decision on the ancestry of black millet. another putative ancestor for true fonio. Digilaria /uscescclIs was Both D. lrmgifiora an d D. tenwf{/ have very wide geograph ic shown to be morphologicall y close to D. exilis (Clayton 1972), distribution as indicated above. In contrast to these wild species. with the two appearing in one duplet of the key to tropical west the fonio millets are conti ned to small regions in tropical west African Digilaria. Digitaria /uscescells and true fo nio are c h ar~ Africa, and have been regarded as endemi c crops (Harlan 1992). acteri zed by the glabrous spikelets, a trait that distinguishes them Therefore, in spite of the genetic variabili ty observed in true from D. /ollgiflora that has spikelets with short appressed hairs. fonio, the genetic resources available from lhe cultivated types In contrast with these repo rts, Porteres (1 976) maintained that are constrained by the endemic natu re of the crops. It has been the identity of the ancestral species of true fonio remained demonstrated that wild species are gen~ ti c ally more variable than doubtful. their respective crops (Plucknett et af. 1983; Hilu 1994a; Hil u Digilnria jllscescells shared very few RAPD bands with most 1995). The wide geographic distribut ion of the wild progenitors of the true fonio accessions as it is apparent from the low Dice over large geographic areas underscores their importa nce as val ­ similarity (0.00 and 0.21) between the two (Table 3). Digitaria uable resources of genet ic material. DiRiraria tenwta, for fuscescell s did not cluster with the accessions of true fonio: instance, varies from an erect tall to a creeping plant, grows in a instead, it was last [Q join the phenogram, clustering with the D. variety of soils anti associates wi th ~\ ra nge of plant communities iburua-D. remota group al a very low similari ty level of 0.1 3 such as grasslands, open shrub savanna, in dry areas or along (Figure I). Similar results were also obtained from the pea and streams, and as a weed in farmlands and along road sides. Con­ MST analyses (Figure 2). Therefore, the lack of geneti c si milari­ certed e fforts need to be made to collect and conserv~ the genetic ti es between true fon io and D. juscescells does not support the resources of the wi ld progenitors of tonio millets. In addition . Ihe proposed genomic relationships between the two species. gcrmplasm collections for the domesticated species, particul arly Although true fonio resembles D. fllscescens in the glabrous black fonia, al so need to be expanded. Fonio mi llets arc impor­ spikelet, the two differ in a nu mber of other morphological traits. tant millets in certain parts of Africa, and show pro mi se for agri- 190 S. Afr. l . Bol. 1997. 63(4)

culture in less arable lands and in the dryer regions of the world. amplified polymorphic DNA. Gellome 38: 232- 238. LEWICKI. T. 1974. West African Food in the Middle Ages. pp. 37-3R. Cambridge University Press. London. 1974. Acknowledgments MALLESHl, N.G. 1989. Processing of small millets for food and indus­ The authors thank the U. S. Department of Agriculture, Southern trial uses. In: Small Millets in Global Agriculture. cds. A. Seetharam, Regional Plant Introduction Station. International Livestock K.W. Riley. & G. Harinarayana, pp. 325-339. Oxford & ISH Publish­ Center for Africa, and the National Institute of Agrobiological ing Co. PVT. LTD .. New Delhi. Resources of Japan for supplying the seed material. This MANDELBAUM. C.1 .. BARB EA U. W.E. & HILU. K'\v' 1995. Protein, research was supported under grant No. DHR- 5600-G-OO- calciu m, and iron conlent of wi ld and cultivated species of Echinoch­ 1073-00, Program in Science and Technology Co-operation, loa mi llets. PI. Foodt lor HI/II/all Nl/lrir. 47: IO I-IOB . Office of the Science Advisor, U. S. Agency for International M' RIBU, H.K. & HILU, K.W. 1994. Detection of interspecific .lnd Development. We also thank Dr. H. P. Linder fo r the constructive intraspeci fi c vari.ltion in POllicli /ll millets through random amplified rev iew comments. polymorphic DNA. Th eor. AI'I'I. Cellet. 88: 4 12-4 16. M' R1BU , K. & HILU. K.W. 1996. Application of random amplified pol­ References ymorphic DNA to study genetic diversity in Pa.'ipallllll .H.:robic:ulatlllll L. (Kodo millet, ). Gellet. Re.'iou r. Crop Evol. 43: 203-210. BARBEAU, W.E. & HILU, K.W. J993. Protein, calcium, iron, and MUNSON, P. 1976. Archaeological data on the origin of cultivation in amino u!.:id contents of selected wild and domesticated cultivars of fin ­ the southwestern Sahara and their implication for West Africa. In; ger millet. Pl. Food/or Hu mOll Nutr. 43: 97-104. Origin of African Plnnl Domesti cation, cds. J .R. Harlan, J.MJ . de Wet CLAYTON. W.D. 1972. Gramineae. In: Flora of West Tropical Africa, eds. J. Hutchinson a nd J.M. Dalziel. 2nd edn, revised by EN. Happer, & A.S.L. Stemler, Mouton Press, The Hague. Netherlands. pp. 574. The Crown Agents for the Colonies, London. MURDOCK, G.P. 1959. Africa: ils people and their cultural hi story. CLAYTON, W.D. & RENVOIZE, S.A. 1986. Genera Graminum. McGraw-Hill, New York. Grasses of the World. Kew Blfll. Additiollal Series XIII. NEJ, M. & L1 , W.H. 1979. Mathematical rn odel for studying genetic var­ CLARK, J.D. 1976. Prehistoric populations and pressures favoring plant ialion in tenus of restrictions endollucleases. Pmc:. N(ttl. A cad, Sci. domestication in Africa. In: Origins of African Pl ant Domestication, USA 76: 5269-5273. cds. lR. Harlan, J.M J . de Wet & Ann S . Stemler, Mouton Publi shers. PLUCKNETT. D. L.. SM ITH, N.J. H.. WILLIAMS, l.T. & ANI· The Hague. Paris. pp. 67-105. SHETTY. N.M. 1983. Crop germpl asm conservation and developing DALZIEL, J.M. 1937. The Useful Plants of West Tropical Africa. An countries. Sc iel1 L'(~ 220: 163-169. Appendix to The Flora of West Tropical Africa. J. Hutchinson and PORTERES, R. 1946. L'air cult urale du DigiUlria ibllrua Stapf. cereale J.M. Dalzie l. The C rown Agents for the Colonies. London, pp. 6 12. mi neure de ]'Ouest-Africcain. L'AgnJlwmie Tmpicole 1( I I . 12): 389- DE WET. J .M J . 1989. Origin, evolution and systematics of minor cere~ 392. als. In: Small Millets in Global Agriculture. eds. A. Seetharam. K.W. PORTERES. R. 1955. Les ccreales mineurcs du genre Digitaria en Afri­ Riley and G. Hari narayana. Oxford & IBH Pub\. Co., New Delhi. pp. que et en Eu rope. Jour. d'Agric. Trup. et de Bot. Appl. 2. t9-30. PORTERES, R. 1976. African Cereal s: EfeuJilJe, Fonio. Black Fonio, DleE. L.R. 1945. Measures of the amount of ecological association . Brac:hiaria. Pa.t/W[UIIl. Pel/Ilise/IIII/ . and African Rice. In: Origins between species. E(:%li.l' 26: 295-302. of African Plant Domestication, eds. J.R. Harlan, J.MJ. deWel. & DOGGETT, H. 1989. Small m illets-a selective overview. In: Small Mil­ A. S .L. Siernler. pp. 409-452. Moulton. The Hauge. lets in Global Agric ulture, eds. A. Seetharam. K.W. Riley & G. Hari­ PURSEGLOVE. J.W. 1972. Tropical Crops: l. Long­ narayana, pp. 3-IB. New Delhi : Oxford & ISH Pub. Co. PVT. LTD. man Group Limiled. London. HARLAN. J.R. 1977. The Origins of Cereal Agricu lture. In: Origins of RAO, M.V. 1989. The small millets: their imporlance. present status and Agriculture. ed. C.A. Reed. pp. 357-383. Mouton Publishers. The outlook. In: Small Millets in G lobal Agriculture. cds. A. Seetharam, Hague. K.W. Riley & G. Harinarayana. pp. ix-xii. Oxford & ISH Publishing HARLAN. J.R. 1992. Crops & Man. 2nd ea., American Society of Co., New Delh i. Agronomy and Crop Science SOCiety of A merica. Madison. Wiscon­ RO HLF. FJ. 1993. NTSYS·PC Numerical and Mu ltivariale sin. A nalysis System, Vers ion UW, Exeter Pubt.. Ltd .. Setauket, New HARRIS, D.R. 1976. Traditional systems of plant food production and York. the origi ns of agriculture in West Africa. In: Origins of African Plant SNEATH, P.H.A. & SOKAL. R.R. 1973. Numerical Taxonomy. pp. Domesti cation, eds. J. R. Har lan, J. MJ. de Wet & A.S. Ste mler, pp. 234- 235. W.H. Freeman & Co .• San Francisco. 3 11- 356. Mouton Publishers, The Hague. STAPF, O. 1915. Iburu and fundi, two cereals of Upper Guinea (Digi­ HENRARD.1.T. 1950. Monograph of the genus Digiraria . Leaden Univ. laria iburua: D. ('xiii... ). Kew Bull.: 38 1-386. Press. Leaden. STEWART, C.N. & VIA. L.E. 1993. A rapid CTAB lechnique usefu l for HILU. K.W. 1994a. Evolution of domesticated plants. In: Encyclopcdia RAPD fingerprinting and other PCR applications. BioTechnique.f 14: of Agricultural Science. ed. C. J. Arntzen. Vol. 2. pp. 117-127 Aca­ 748-748. demic Press. WILLIAMS, l .G.K.. KUBELIK. A. R., LlVAK. K.l ., RAFALSKI , l .A. HILU. K.W. 1994b. Evidcnce from RAPD markers in the evolution of & TINGEY, S.V. 1990. DNA polymorphisms amplified by arbitral)' EchiflochllJC/ millets (Poaeeae). PI. S)'st. Evol. 189: 247- 257. primers are useful as genelic markers. NIH:i. Acid.\' Res. 18: 6531- HILU. K.W. 1995. Evolution of finger millet evidence from random 6535.