Volume 86 1977 > Volume 86, No. 4 > The sweet potato in the south-eastern Solomons, by Harold M. Ross, p 521-530
THE SWEET POTATO IN THE SOUTH-EASTERN SOLOMONS
The common sweet potato (Ipomoea batatas) has been an enigma for anthropologists, ethnobotanists and students of Oceania. No one questions its pantropical distribution or its value as a food crop. It was of paramount importance in some Pacific areas (notably Hawaii, New Zealand and the New Guinea Highlands), and today it is the most widespread cultigen in the south-eastern Solomon Islands. However, speculation and controversies about its origin and dispersal have been frequent. 1
Yen has proposed the following tripartite theory of sweet potato distribution. 2 It was first domesticated in tropical America as part of an early Tropical Forest root crop horticultural pattern. 3 Pre-Magellanic voyagers carried it to eastern central Polynesia, whence it diffused to other islands prehistorically (the kumara line); a second dispersal route was from the Caribbean via the Mediterranean, Africa and India to Indonesia and New Guinea through the agency of 15th-16th century Iberian, Arab and Malay sailors (the batata line); while the third route was directly across the Pacific from Mexico to Guam and the Philippines by the 16th-17th century colonial Spanish (the camote line). 4 Yen's comprehensive synthesis may not be the last word, but it elevates our understanding to a new plateau. The best services commentators and researchers can perform now are to resolve ambiguities, clarify details, fill in gaps, and add new evidence from specific localities.
Because it is unlikely that the sweet potato came directly from America to the south-eastern Solomons, the prudent course is to assume it was introduced there from nearer areas, Polynesia and New Guinea, where it was already established. 5 The case for prehistoric sweet potatoes in eastern and especially marginal Polynesia is compelling. Cook and his botanists offer direct eye-witness testimony and physical evidence that the plant was cultivated in New Zealand, Tahiti, Easter Island and Hawaii at the inception of the ethnohistoric period. 6 On the one hand, ethnological age/culture area concepts imply that traits common to the outer margins probably derive from a more central (and pre- - 522 sumably older) area. 7 Furthermore, Occam's razor favours the more parsimonious notion of a single introduction of sweet potatoes into central eastern Polynesia, with subsequent dispersal to marginal Polynesia, over a theory of independent introductions at unknown times by unknown agents separately to various island groups, because the joint probability of independent events is calculated by multiplication, not addition. 8 The fact that one can reconstruct the Proto-Polynesian *kumala for sweet potato is presumptive evidence for an Austronesian origin of the word, 9 and (from a Wörter und Sachen point of view) indirect evidence for the presence of the plant itself in precontact Polynesia. 10 On the other hand, there is little reason to believe that sweet potato was of much importance in central, western or nuclear Polynesia (Samoa, Tonga and Fiji); negative evidence implies its prehistoric absence and ethnobotanical data indicate that European sailors introduced the present varieties. 11 Likewise, in New Guinea, despite hints of horticultural antiquity, most evidence suggests a Post-Columbian entry of sweet potatoes from Portuguese-Dutch bases in Indonesia, along with the better known American plants, tobacco (Nicotiana tabacum) and corn (Zea mays). 12
Regardless of when it arrived, the sweet potato's potential was not appreciated in the central Pacific. It intruded into Polynesian gardening, where it supplemented Melanesoid and South-east Asian cultigens, but remained a secondary crop. 13 Sweet potatoes are high yielding, non-seasonal, nutritious, durable, pathogen resistant, hardy against weed competition, and adaptable to a wide range of edaphic and climatic conditions. In marginal areas of coolness in higher latitudes or altitudes (New Zealand and Highland New Guinea), of seasonal weather variations (Hawaii and Easter Island), or where plant pathologies create horticultural problems, sweet potatoes became important. But in central and western Polynesia disinterest was probably more significant in the absence of environmental limitations; the older crops were sufficient, and there was little motivation to accept and promote yet another farinaceous food plant. 14
In the contemporary south-eastern Solomons, the sweet potato rivals taro in significance, yet it is by no means proved that it has been important in the culture history of Island Melanesia. Certainly ethnographic, ethnohistorical, linguistic and ethnobotanical data from the Baegu people of northern Malaita, where Melanesian-Polynesian connections are particularly obvious, do not support a case for sweet potato antiquity there.
There are about 2300 Baegu, who speak one dialect of the Lauic language, which also includes the dialects Lau, To'abaita, Baelelea and Fataleka. They are relatively light skinned Melanesians who inhabit northern Malaita's forested interior, live in widely dispersed small hamlets, and practise swidden farming of typical Melanesian food crops, which they barter for fish at coastal market-places. Traditional social organisation is based upon a structure of agnatic clans and a patrilineal ideology of real property title, combined with cognatic definition of jural rights and duties and a bilateral kinship terminology system. Their pagan religion was an animistic ancestor worship, supported by a puritanical tabu code and an elaborate ceremonial cycle. Today, about a third of the Baegu remain - 523 pagan; the rest are converts to Roman Catholicism, the Anglican Melanesian Mission, the fundamentalist South Seas Evangelical Church, or Seventh Day Adventism. 15
Root vegetables are the Baegu subsistence basis. Sweet potatoes and three species of taro form 59 percent by bulk of their diet and provide over 80 percent of their caloric intake. (Yams, that prefer the sandy, drier and better drained conditions at lower altitudes, are more important among coastal populations.) Of these dietary fractions, sweet potatoes alone constitute about 57 percent. 16 Nevertheless, the Baegu overwhelmingly prefer taro (Colocasia esculenta) to sweet potatoes and even swamp taro (Cyrtosperma chamissonis) and bush taro (Alocasia macrorhiza) are considered tastier. 17
Some vegetables are ritually important. Taro (Colocasia esculenta) is the sacred crop, grown by men and boys for maoma ‘mortuary festivals’ where swine are sacrificed for the ghosts of the dead. Among the Lau, coastal neighbours of the Baegu, yams are used in this context. Sweet potatoes are a secular crop, raised by men or women, with no ritual connotations, and they are often planted as a second crop in swiddens following the taro harvest. There are folk tales and ri'iri'i ‘ritual orations’ describing the origins of taro, yams, the areca nut palm, sugar cane, bananas and other useful plants; but there is none concerning the sweet potato, and people laugh when asked if there are any.
The anomalous pre-eminence of sweet potatoes can be explained in part by a taro blight (Phytophthora colocasiae) that began ravaging the common taro in Malaita in the early 1950s. Taro blight is a leaf-spotting plant disease that spreads to stems and becomes a soft rot of the corms in humid conditions. 18 In traditional Baegu cosmology blights (like epidemics and natural catastrophes) are believed to be caused by the ill-will of the akalo ‘ancestral spirits’. Even when the taro was not killed outright, corms were much smaller and yields greatly reduced. Throughout Malaita crop failures were frequent, there was barely enough taro to meet demands of the ceremonial cycle, and there was no surplus for barter; farm production, ritual and trading patterns were disrupted, and demoralised men lost interest in gardening. 19 During the 1960s the virulence of the blight dissipated somewhat, and the Colocasia taro industry partially recovered; but even today people say the taro crops are bad. Sweet potatoes remain the dominant staple.
Besides this apparent lack of functional integration into the overall pattern of Baegu culture, there are other indications that sweet potatoes may be a relatively recent intrusion here, as in Micronesia and parts of Polynesia, into a traditional horticulture where yams and taro were the dominant cultigens. 20 Preliminary archaeological reconnaissance has not discovered evidence for prehistoric sweet potatoes in Melanesia, and it has not been possible to reconstruct a Proto-Melanesian form of the word. 21 References by Mendaña and Quiros to root crops in the Solomons and New Hebrides are based on doubtful identifications and are unreliable at best. 22 Certainly Cook did not substantiate the presence of sweet potatoes in the New Hebrides and New Caledonia, nor did he identify the “sorts of potatoes” he saw there with the Polynesian kumara with - 524 which he was already familiar. 23
Genetically and botanically, Solomon Islands sweet potatoes resemble both Polynesian and New Guinea varieties, implying mixed derivation from those two sources, 24 but there are no positive data favouring their prehistoric introduction. Instead, there are grounds to suspect that the sweet potato did not reach the Solomons before intensive and continuous European contact began in the second half of the 19th century. 25
The word kumala for sweet potato in Solomon Islands Pidgin does not necessarily imply introduction of the plant from the Polynesian outliers. 26 The languages of these intrusive immigrants (Rennell and Bellona, Sikaiana and Ontong Java being closest to Malaita) are part of a Samoic-Outliers subgroup, 27 which means they probably came from the vicinity of Samoa, where the sweet potato was unimportant and perhaps not even known prehistorically. They are unlikely to have brought the plant, if it was not important in their homeland. In most Pidgin dialects used on Malaita, the word for sweet potato is kumara. In some Malaitan vernaculars, all of which belong to a South-eastern Solomonic subgroup, 28 /I/ and /r/ are contrasting phonemes; in others they vary freely or in complementary distribution. The Baegu form, kumara, comes directly from the New Zealand Maori.
In Anglican Baegu villages during 1966-68, old people born in the 1880s said without equivocation that youths returning from mission schooling in New Zealand or Norfolk Island brought the kumara plant back to Malaita with them during the reign of Queen Victoria. Bishop Selwyn, the first Anglican prelate of New Zealand, was given responsibility for missionary activity in the Pacific Islands. 29 He visited the Solomons aboard HMS Dido in 1847, matriculated the first Melanesian students at St. John's College in suburban Auckland in 1848, established the Melanesian Mission in 1849, and baptised the first Solomon Islander (Didi of San Cristobal) in 1850. 30 In 1862 Bishop Patteson took three Malaitamen from Sa'a with him to New Zealand. 31 The Melanesian Mission school was moved to Norfolk Island in the Tasman Sea in 1862. It remained there until 1919, graduating about 20 young men each year to return to their home islands to spread their new faith and learning among their friends and relatives. 32 Both in suburban Auckland and on Norfolk Island, Melanesian Mission school boys subsisted upon sweet potatoes that were given to them because they were the New Zealand vegetable most closely resembling the root crops (taro and yams) that comprised the diet back home in Melanesia. The students were required to cultivate this New Zealand vegetable as part of their school duties. Having acquired a taste for sweet potatoes while at school and appreciating their qualities as a cultivar, graduating students took sweet potatoes and the Maori name kumara back home to the islands.
It is also possible that, during the same time period, Solomon Islanders returning from indentured labour on plantations might have imported sweet potatoes. The Melanesian labour trade flourished after 1870, when industrial demand for tropical products stimulated development in Queensland, New - 525 Guinea, New Caledonia, Fiji and Samoa, and over 30,000 Solomon Islanders were recruited for work abroad. 33 It was on plantations that the Neo-Melanesian Pidgin language evolved and Melanesians acquired the taste for various Western goods. By the 1890s Solomon Islanders, who had been converted to fundamentalist Protestantism while in Australia, were returning home to Malaita to proselytise for the South Seas Evangelical Mission. 34 Had they been eating sweet potatoes in plantation labour lines, it is logical to assume that they might have taken cuttings or tubers home with them along with their new religion and other foreign artefacts. Rice, however, was the most common plantation ration. Nevertheless, such a source and route would explain the mixture of New Guinea and Polynesian characteristics in Solomon Islands sweet potato stock. 35
The spread of the sweet potato and its Maori name kumara was facilitated because the people of the south-eastern Solomons (Malaita, San Cristobal, Guadalcanal, Santa Isabel and the Nggela group) were involved in a traditional system of swine and shell money trading that shared a common body of myth, worldview and iconography. 36 The plant quickly became established in Malaita. With a few specific exceptions it is nutritionally equivalent to taro; 37 its productivity in mass and kilocalories is at least as great as that of taro; 38 it is
Solomon Islands Food Plants and Related Terms.
not seasonal; it is hardy under virtually the entire range of growing conditions in the Solomon Islands; it is immune to the blights and other plant diseases that affect taro; and it is so fast-growing that gardens need little or no weeding. Given good yield and low risk in a situation where the existing crop was providing variable yields, it would be highly reasonable to adopt an equivalent new crop, like the sweet potato, whose performance was more reliable and predictable. Most important, its yields and susceptibilities to environmental factors appear to vary independently from those of taro. 39 Thus, according to the lucid memories of Baegu octogenarians: Malaitans did not know the sweet potato in their grandparents' generation; young men educated by the Melanesian Mission brought the plant home from Anglican schools in New Zealand or Norfolk Island; it spread throughout the south-eastern Solomons because people found it useful; and its Maori name kumara became the Solomon Islands Pidgin word for sweet potato.
The Baegu vernacular name for the sweet potato has no relation to the kumala/kumara form, but it is an integral part of the native ethnobotanical semantic domain. Table I gives glosses in English and the Solomon Islands dialect of Neo-Melanesian Pidgin for Baegu plant names and related terms, which can be compared to terminology from other Malaitan languages. 40 There are legitimate vernacular words for traditional Indo-Pacific food plants, but for more recent acquisitions they have coined new words based upon perceived characteristics. For the very most recent garden vegetables, introduced by the British during the 20th century (cucumbers, melons, pumpkins, shallots and tomatoes), they simply borrow, with appropriate phonological modifications, the colloquial English names. 41
In traditional times inter-ethnic and inter-island commerce was conducted in languages of coastal peoples like the Lau and Langalanga of Malaita, who dominated the minting and distribution of shell money and whose diet emphasised yams. The post-contact trade language did not use such forms as the Lau and Baegu fanga ‘food’, ania ‘to eat’ and sarea ‘to feed’. 42 The Pidgin evolved by these Melanesians, for coping with their own Babel of vernaculars and European colonial commerce and government, adapted the common Solomon Islands word kai ‘yam’, that is specifically Malaitan and possibly also Proto-Polynesian, 43 - 527 as the etymological root for its kaikai, used both as the noun ‘food’ and the verb ‘to eat’. 44
There are several typological plant categories in Baegu: 'ai ‘tree or large shrub’, kwalo ‘shrub or semi-climbing vine’, wai ‘vine or trailing herb’, and lalane ‘weeds or grass’. To indicate something domesticated or cultivated, they add the modifiers fera ‘hamlet place’ or ole ‘garden’. A wild object is kwasi ‘wild’ or gano ‘earth or bush’. The modifiers asi ‘ocean’ and faka ‘ship’ denote that something is of foreign origin. 45
Baegu names for the Caribbean papaya (Carica papaya) and passionfruit (Passiflora sp.) are examples of the principles they employed in naming new foods. Solomon Islander workers brought the papaya home from Queensland plantations, where it is a commercial orchard crop. Passionfruit came from Fiji, where it has been grown for the soft drink industry. In Baegu the papaya is 'ai asi ‘the tree from overseas’. For the passionfruit, they phonologically adapted the Pidgin name switropu (which can be literally translated as ‘delicious vine’) into the Baegu suitarobo.
The yam, called kai in Baegu, is a herby vine with a trailing or climbing habit of growth. Its underground tubers vary in shape, but they are often phallic, and Pacific peoples may see them as male symbols. 46 Yam leaves are chordate (Dioscorea alata, D. bulbifera and D. esculenta) or palmate (D. pentaphylla and D. hispida). 47 All but the last are native to the Solomons. 48
Manioc or cassava (Manihot dulcis), known to have been introduced from South America to feed Melanesian plantation workers in the 19th century, 49 grows as a shrub with woody stems up to 8 feet tall. 50 Its tubers are phallic in shape, and its palmate leaves resemble those of Dioscorea pentaphylla, yet it stands upright and is tall enough to belong to the ‘tree or shrub’ category. Hence its Baegu name is kai 'ai ‘the yam that grows like a tree’. 51
Sweet potatoes are trailing herby vines. They are members of the Convolvulaceae or morning glory family, and their funnel-shaped white or pink flowers resemble morning glories. Sweet potato tubers can be yam-like (Southern Americans for example call yellow sweet potato tubers “yams”), and their chordate-lobed leaves can superficially resemble almost any of the Solomon Island yams. 52 One of the pioneer species in Malaitan plant succession is a common blue-flowered, sun-loving wild morning glory (Ipomoea congesta), known as rogi in Baegu, that proliferates along streambanks and trails and in abandoned garden plots. 53 Hence the Baegu name for the sweet potato is kai rogi ‘the yam that grows like a morning glory’. 54 In southern Malaita and Maramasike the Lau, 'Are'are and Sa'a people confirm its recent foreign origin by naming the sweet potato kai asi ‘the yam from overseas’, 55 which is analogous to the Baegu for papaya.
Once there is a general understanding of the agronomy, botany and range of a domesticated plant and a viable theory of its centre of origin and routes - 528 of dispersal, it is appropriate to refine that theory through research on the plant in specific geographic locations. It now appears that the sweet potato (Ipomoea batatas) originated in tropical America, spread to eastern Polynesia in prehistoric times, and reached New Guinea and Micronesia via two separate routes after the European discovery of America. The plant may or may not have got to Nuclear Polynesia or Island Melanesia before European exploration of that part of Oceania. Baegu oral literature, ethnobotany, taxonomic nomenclature and horticultural ethnography, however, make it seem unlikely that the sweet potato reached Malaita in the south-eastern Solomon Islands until after intensive European contact began in the 19th century, when it was imported by mission schoolboys or plantation hands.
1 De Candolle 1886; Dixon 1932; Merrill 1954; Barrau 1957; Murdock 1959; Conklin 1963; Heyerdahl 1963; Brand 1971; O'Brien 1972; Dickeman 1974.
2 Yen 1974.
3 Lathrap 1970:512-4; O'Brien 1972:361; Yen 1974:22-5.
4 Yen 1974:259, 329-30.
5 Yen 1974:256-9.
6 Yen 1974:8-10.
7 Dixon 1928; Nordenskiold 1930; Kroeber 1931.
8 Harlan and De Wet 1973:54.
9 Andrews 1865:113; Walsh and Biggs 1966:40; Pukui and Elbert 1971:170.
10 Swadesh 1964:539.
11 Yen 1974:10-11.
12 Riesenfeld 1951; Watson 1965; Heider 1967; Cutler and Blake 1971; Jeffreys 1971; Nelson 1971; Sorenson 1972; Foster 1973; Sorenson and Kenmore 1974.
13 Yen 1974:291-2.
14 Yen 1974:294-5, 331.
15 Ross 1973.
16 Ross 1976:576-8.
17 Ross 1976:572.
18 Weber 1973:237.
19 Keesing 1965:38-9.
20 Yen 1974:321; Barrau 1958 and 1961.
21 Chowning 1963:40-41; Yen 1974:31.
22 O'Brien 1972:356; Yen 1974:7-8.
23 Yen 1974:9.
24 Yen 1974:257.
25 Morrell 1960; Oliver 1961; Corris 1973.
26 O'Brien 1972:356.
27 Pawley 1967:259-60.
28 Pawley 1972:98-9, 107-10.
29 Armstrong 1900:3.
30 Fox 1967:31.
31 Ivens 1927:23; Boutilier 1977.
32 Fox 1967:31.
33 Corris 1973:1-5, 24-44; Boutilier 1977.
34 Hilliard 1969:45.
35 Yen 1974:256-9.
36 Fox 1925; Ivens 1927 and 1930; Hogbin 1939 and 1964; Corris 1973:18-9; Terrell 1974:31-2.
37 Ross 1976:578.
38 Rappaport 1967:49-50 and 1971:350; Kimber 1970:35-6; Sivan 1970:152-3.
39 According to Tobin's portfolio-balance theory from macroeconomics (Branson and Litvack 1976:253-61) and the Markowitz capital-asset pricing model used in finance (Van Horne 1974:41-57), the expected value of an investment (defined as the acquisition of resources meant to provide future benefits) is a function of the rate of return (y) and the risk (s) involved.
Ev > f(y, 1/s),
Mean yield is a measure of return, and standard deviation of yields measures risk This can be expressed in a capital budgeting decision algorithm, where the expected value of an investment (new asset) is directly proportional to average return but varies inversely with standard deviation squared (variance), and these are functionally related to an exogenously determined risk-free rate of return and the covariance between an existing set of assets and an additional new asset; which can be used to assess the impact of an incremental addition (investment in a new asset) upon the value of a portfolio (set of existing assets), and hence can be employed to maximise wealth (portfolio value) by indicating whether to accept or reject a proposed increment (Bierman and Dyckman 1976:375-7). Using these analytic techniques, it can be demonstrated that it would be rational (and profitable) to add to one's horticultural portfolio a new crop, like the sweet potato, that yields as much as taro but is not vulnerable to the same hazards.
40 Yen 1974:341.
41 Ross 1976:572.
42 Ivens 1921:30 and 1934:11, 32, 47, 91.
43 Ivens 1934:53; Walsh and Biggs 1966:24.
44 Mihalic 1971:101-2; Dutton 1973:34.
45 Ivens 1934:9, 14, 32, 33, 40, 59, 71, 81, 86, 87.
46 Barrau 1965:337.
47 Malcolm and Barrau 1954:29.
48 Barrau 1958:43.
49 Barrau 1958:47.
50 Massal and Barrau 1955a:15.
51 Ivens 1934:53.
52 Massal and Barrau 1955b:10.
53 Whitmore 1966:187; Leach 1973.
54 Ivens 1934:53; Yen 1974:341.
55 Yen 1974:18, 341.