Maintenance of Manioc Diversity by Traditional Farmers in theState of Mato Grosso, Brazil: A 20-Year Comparison1

FÁBIO FRATTINI MARCHETTI*,2, LUIZ ROBERTO MASSARO JUNIOR2,

MARIA CHRISTINA DE MELLO AMOROZO2, AND DAVI BUTTURI-GOMES

3

2Departamento de Ecologia, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil3Departamento de Ciências Exatas, Escola Superior de Agricultura Luiz deQueiroz, Universidade de São Paulo,Piracicaba, São Paulo, Brazil*Corresponding author; e-mail: fabiofrattini@hotmail.com

Maintenance of Manioc Diversity by Traditional Farmers in the State of Mato Grosso, Brazil:A 20-Year Comparison. Few studies discuss agrobiodiversity in the Brazilian savanna, whichis believed to be the geographical origin of manioc and is one of its centers of diversity. Using anethnobotanical approach, we evaluated the varieties of manioc cultivated by traditional farmers inthe region, comparing two years: 1992 and 2011. Participant observation and semistructuredinterviews were conducted in both years in the same communities—27 farms in 1992 and 30 in2011. Area of cultivated land was measured, all the manioc varieties identified by the farmers wereinventoried in the fields, and the crop density was estimated. Diversity was similar for both years(1992: 60 varieties, H’ = 1.53; 2011: 54 varieties, H’ = 1.52); however, the mean number ofvarieties per farmer decreased from 9.4 ± 4.5 to 5.4 ± 4.4. The frequency and abundance of thevarieties also changed. Varieties that were uncommon or nonexistent in 1992 were found to becommon and occupying larger crop areas in 2011, and vice versa. Agricultural activity hasdecreased considerably; the mean size of cultivated areas has been reduced by two-thirds, and themajority of young people are not engaged in agricultural activities at all or only part-time. Thesefindings point to serious threats to local agrobiodiversity and the need to discuss ways tomaintain it.

Manutenção da diversidade de mandioca por agricultores tradicionais do Estado de MatoGrosso, Brasil: Uma comparação em 20 anos. Poucos estudos discutem a agrobiodiversidade nocerrado brasileiro, região indicada como origem geográfica e um dos centros de diversidade damandioca. Através de uma abordagem etnobotânica, avaliamos o acervo das variedades demandioca cultivadas por agricultores tradicionais da região, comparando dois períodos: 1992 e 2011.Observação participante e entrevistas semi-estruturadas foram realizadas em ambos os períodos, nasmesmas comunidades—27 e 30 sítios, respectivamente. Foram medidas as áreas de cultivo,inventariadas todas as variedades de mandioca identificadas pelos agricultores nas roças e estimadassuas densidades. A diversidade foi similar para ambos os períodos (1992: 60 variedades, H’ = 1,53;2011: 54 variedades, H’ = 1,52), porém o número médio de variedades por agricultor diminuiu de9,4 ± 4,5 para 5,4 ± 4,4. A frequência e abundância das variedades também se alteraram.Variedades pouco frequentes ou inexistentes, em 1992, são bastante comuns e ocupam maioresáreas de cultivo em 2011 e vice-versa. A atividade agrícola tem se reduzido notavelmente: otamanho médio das roças diminuiu em dois terços; e a maioria dos jovens não realiza maisatividades agrícolas ou as faz em tempo parcial. Com isso, a agrobiodiversidade local estáameaçada e propostas para sua manutenção são discutidas.

Key Words: Manioc, agrobiodiversity, ethnobotany, Cuiaba Lowland.

IntroductionAgroindustrial patterns and the consequent genet-

ic erosion of crops have reduced the genetic diversityof cultivated plants by three-quarters, threateningfood security mainly in the poorest regions of theworld (FAO 1997, 2010; Nabhan 2009). The

1Received 25 January 2013; accepted 17 September2013; published online 9 October 2013 .

Electronic supplementary material The online ver-sion of this article (doi:10.1007/s12231-013-9246-3)contains supplementary material, which is available toauthorized users.

Economic Botany, 67(4), 2013, pp. 313–323© 2013, by The New York Botanical Garden Press, Bronx, NY 10458-5126 U.S.A.

dissemination of commercial seeds and the exodusof farmers to non-farm employment are the mainfactors contributing to the erosion of genetic andtraditional knowledge (Brush 2002). Local cropshave been substituted or had their genotypecontaminated by commercial ones in differentparts of the world, such as maize in Mexico(Heerwaarden et al. 2009), sorghum in Cameroon(Alvarez et al. 2005), barley in Ethiopia (Eticha etal. 2010), and rice in China (Fu et al. 2010).This historical process has led to world interest

in landraces (Camacho-Villa et al. 2005) due totheir role in food security, especially for traditionalhousehold farmers (local scale), and as naturalsources of resistance for biotic and abiotic stress inagriculture (global scale), including their uses ingenetic improvement programs (Valle 2002; Woodand Lenné 1997).Manioc (Manihot esculenta Crantz, Euphorbi-

aceae) is the most important source of carbohy-drates and staple food for nearly 800 millionpeople, mostly in the tropics, where its produc-tion is intimately associated with low-incomefamilies (Clement et al. 2010; FAO, IFAD2000). There are estimated to be thousands ofvarieties of M. esculenta cultivated by farmersaround the world (Elias et al. 2004), but recentevidence points to the southwestern border of theAmazon basin, from the Brazilian savannas to theAmazon forest, as being the geographic origin ofthe species (Isendahl 2011; Léotard et al. 2009;Olsen and Schaal 1999, 2001).The richness of varieties of manioc has been

widely documented, from the ethnobotanical as wellas the genetic perspective, mainly in the Amazonregion (Chernela 1986; Elias et al. 2004; Emperaireand Peroni 2007; Fraser et al. 2012; Resende et al.2000; Salick et al. 1997, among others). However,few studies have been carried out in the west-central region of Brazil, in the state of Mato Grosso(Amorozo 2000; Barelli et al. 2005; Morais et al.2009; Siqueira et al. 2009), which is one of theregions known to be a center of manioc diversity,and where it is believed the species was firstcultivated (Isendahl 2011; Nassar 2002).Longitudinal studies of agrobiodiversity manage-

ment by traditional farmers are important toidentify the elements that determine the dynamicsof local diversity and to inform the implementationand evaluation of on-farm agrobiodiversity conser-vation programs (Wood and Lenné 1997). Never-theless, studies of diversity and its temporaldynamic are rare, particularly in the case of manioc

(Fu et al. 2010; Hamlin and Salick 2003; Lima etal. 2012; Peroni and Hanazaki 2002).In the Cuiabá Lowland, south-central region of

Mato Grosso, numerous traditional communitiesstill cultivate manioc, mainly for subsistence.However, the influence of modernization inrural areas has brought changes to the lifestylesof these populations. There is an urgent needto study these agricultural systems and the impactsof these transformations on the agrobiodiversitythat is found there. Using an ethnobotanicalapproach, this study evaluated the changes in theassortment of manioc varieties cultivated by tradi-tional farmers in the Cuiabá Lowland, comparingthe situation in 2011 with the situation found twodecades ago (1992).

Materials and MethodsSTUDY AREA

The studies were conducted in traditional ruralcommunities located in an area of cerrado (Braziliansavanna), local ly known as campo-fora(outfield—Barreirinho and Morro Grande) andbeira-rio (riverbank—Estraíra and Varginha), in themunicipality of Santo Antônio do Leverger, MatoGrosso, Brazil. The two areas are located 10 km apart,8 km from the municipal center, and approximately30 km from the state capital, Cuiabá (Fig. 1). Theclimate is predominantly tropical, with two well-defined seasons: a rainy season from October toMarch, and a well-marked dry season from April toSeptember (Alvarenga et al. 1984). Mean annualprecipitation level is 1,314 mm, and the meanannual temperature is 25.6°C (Brasil 2012).The region has been occupied by traditional

communities at least since the 19th century; prior tothat time, it was inhabited by indigenous tribes thatwere decimated by the Iberian colonization in the17th and 18th centuries. The current inhabitantsare descendents of Amerindians, mainly the Guató,enslaved Africans who were brought to Brazil in the18th century to work in the gold mines, andmigrants from the state of São Paulo, who werethemselves a mix of European and indigenousdescent (Siqueira 2002). Until the 1970s, landownership was typically communal, and subsis-tence activities included slash-and-burn agriculture,livestock raising, hunting, fishing, and gathering.Beginning in the 1970s, some of the land began tobe appropriated by ranchers and migrants fromother regions, decreasing the area of the commu-nities and forcing the division and entitlement of

314 ECONOMIC BOTANY [VOL 67

the land. In the 1990s, the farms ranged from 1 to40 ha; slash-and-burn agriculture was still the mainsubsistence activity, but the fallow period wasdecreasing due to space limitations, and someactivities such as the planting and processing oftobacco and production of raw brown sugar werepracticed by few families. On the other hand, thecultivation of manioc and artisanal production ofmanioc flour were flourishing (Amorozo 1996).

In the last two decades, the area has becomeincreasingly modernized through improvements ininfrastructure, including electricity, water supply, andimproved roads. The availability of public transporta-tion has made it possible to travel to nearby cities,facilitating contact with the urban environment andthe movement of the population in search ofemployment and formal education. In addition, somejob opportunities in the tertiary sector became availablelocally due to an increase in tourism in the area.

DATA COLLECTION

In 1992, the communities of Barreirinho,Morro Grande, Varginha, and Estraíra consisted

of approximately 100 family units. Practically allof them were engaged in agricultural activities.Twenty-seven farms were selected by non-ran-dom, purposive sampling (Bernard 1988), toinclude at least one farmer from each extendedfamily that cultivated manioc. An inventory wasconducted of the manioc varieties cultivated inthe fields of each farmer.

In 2011, few families still maintained agriculturalactivities. Therefore, we selected 30 farms inBarreirinho, Varginha, and Estraíra that representedmost of the farmers cultivating manioc in thesecommunities, to inventory the manioc varieties in thefields (Marchetti 2012). Sixty-three percent of thesefarmers were the same farmers who participated inthe study in 1992, 10% percent were their sons whoremained living on their own farms, and 27% werefarmers who had not participated in the 1992 study.

In both years, the sample corresponded toapproximately 25–30% of the total number offarms, and the same method was used to collectdata about manioc varieties. The cultivated areas(fields) were measured and all the cultivated manioc

Fig. 1. Location of the study area: Rural communities of the municipality of Santo Antonio do Leverger, inMato Grosso State, Brazil.

315MARCHETTI ET AL.: MANIOC DIVERSITY IN MATO GROSSO2013]

varieties on each farm were inventoried in the fieldsin the presence of the farmers who identified thevarieties in place. For each one, a record was filledout containing data regarding the characterizationof the variety (origin, age, maturity, durability,preferred end-uses, and agronomic remarks). Foreach reference period, the relative frequency ofvarieties was calculated based on the number offarms where a given variety was found (absolutefrequency) expressed as a percentage of the totalnumber of farms.Several patterns are used for the spatial arrange-

ment of the varieties in the fields. Depending on thefarmer and his needs, manioc varieties werearranged in plots, lines, or randomly mixed in thefields. To estimate the density of the varieties indifferent arrangements, plots measuring 40m2 (2 mx 20 m) were randomly set up in each field. First aside of the field was randomly selected; then, thedirection of the plot—45 º to the left, 90 º or 45 ºto the right—was also randomly selected. Allmanioc individuals of each variety within the plotswere counted, in 22 farms in 1992 and 28 farms in2011. In 1992, two to three plots were set up ineach field (total area of 2,440 m2), whereas onlyone plot was set up in each field in 2011 due tothe reduced size of the fields (total area 1,400 m2).Participant observation and semistructured inter-views were used to collect socioeconomic data andinformation about local agricultural management.We considered “local varieties” or landraces to

be the set of clones with similar characteristicsrecognized by farmers as a single variety. Therefore,landrace diversity is the diversity of ethnovarieties,not the genetic diversity (Elias et al. 2004; Sambattiet al. 2001).The study is part of a larger research project

“Agrobiodiversity conservation and socioeconomicdynamics among small farmers in rural communitiesof Cuiaba Lowland in Mato Grosso” (FAPESPprocess nº 2008/03822-3). It was approved by theComitê de Ética em Pesquisa da UniversidadeEstadual Paulista, campus Rio Claro (protocol nº3633/2010), and by the Conselho de Gestão doPatrimônio Genético do Ministério do MeioAmbiente (CGEN process nº 02000.002717/2009-68).

DATA ANALYSIS

The socioeconomic characteristics of the commu-nities in both years were described and compared. Tocompare the assortment of manioc varieties in the

two years, the Shannon diversity index (H’) was used(Pielou 1975; Zar 2010), adapted for ethnobotan-ical studies (Begossi 1996), as follows:

H 0 ¼ −Xi¼1

S

pi log pið Þ

where pi ¼ ni

n is the proportion of the variety i inthe sample; ni is the number of farms where thevariety i occurred; n=∑ i=1

S ni is the total number ofoccurrences in the sample; and S is the totalnumber of varieties found in the sample. Eachperiod was considered as an independent sample. Inthis study, the logarithms were calculated using base10. In order to test for differences in diversitybetween periods (H0: H′1992 = H′2011 vs. H1:H′1992 ≠ H′2011), we used nonparametric bootstrapestimation methods with 10,000 samples withreplacement, as described in Efron and Tibshirani(1993). The estimates for the Shannon indices andtheir respective variance were then submitted to aHutcheson t-test, as in Zar (2010:156).We applied the Spearman’s ρ to evaluate the

correlation of the number of varieties found in aplot and the actual field size and tested for thehypothesis of different levels of correlationbetween periods (H0: ρ1992 = ρ2011 vs. H1:ρ1992 ≠ ρ2011) using the adjusted Fisher’s z test, asin Zar (2010:395–398). For more robust estimates,we also used the bootstrap approach.

Results and DiscussionDIVERSITY OF LOCAL VARIETIES

The structure of the assortment of local varietiesunderwent significant changes between the twoperiods studied. Varieties that were very commonin 1992, with relative frequency above 70%, in 2011had limited distribution, such as the varieties “Mata-Rato,” “Rama-Dura,” and “Liberata” (Table 1). Onthe other hand, varieties that were less common in1992, or nonexistent, were among the mostfrequent in 2011, such as the varieties “Oiuda,”“Cacau,” and “Pretinha.” Thirty-seven varietiesinventoried in 1992 were not found in 2011(Appendix I online). Close to 70% of them wererare varieties, i.e., planted by only one or twofarmers, in low densities. And 31 varietiesinventoried in 2011 were not found in 1992.The process of change in the composition of the

assortment through loss and acquisition of varieties

316 ECONOMIC BOTANY [VOL 67

over the years is common in traditional agriculture.Peroni and Hanazaki (2002) estimated losses of30.6% of varieties of different species over a 30-yearperiod among caiçara populations (descendents ofPortuguese, Amerindians, and Africans living alongthe southeastern coastline of Brazil) of São Paulostate; and Eticha et al. (2010) estimated 71.4% lossin varieties of barley cultivated by farming commu-nities in Ethiopia (no time period was specified).

In the area studied, the percentage of introductionof varieties during the 20 year period was slightlylower than percentage of loss: 57% and 62%,respectively. As a result, the richness of the varietiesobserved in 1992 was slightly higher than in 2011:60 and 54, respectively (Appendix I). There are fewreports in the literature regarding percentage ofintroduction of varieties. Lima et al. (2012) studiedmanioc diversity in riverbank communities of theAmazon River and found similar proportions: 53%introduction and 56% loss, in a shorter period oftime (five years).

Despite the difference in composition ofmanioc varieties between periods, there were nosignificant differences in the diversity indices(Tables 2 and 3). However, with regard to therichness of varieties per farm, there was a change. Themean number of varieties found per farm decreasedfrom 9.4 ± 4.5 in 1992 to 5.4 ± 4.4 in 2011. Farmswith more than six varieties accounted for 63% ofthe total in 1992 and only 23% in 2011 (Fig. 2).

The decrease in the number of varieties perfarm led to a general decrease in the frequency ofvarieties in the area. The three most frequentvarieties in 1992 were found on more than 70%of the farms, whereas in 2011, no variety occurred on

more than 50% of the farms (Table 1). Compared toother regions in Brazil, the communities in thestudy area presented richness of varieties per farmergreater than the riverbank farmers of the MadeiraRiver and Solimões River in the Amazon (Fraser etal. 2012; Lima et al. 2012; Pereira 2008), similar tothe caiçara populations of São Paulo state, andbelow that of the indigenous communities of theupper Negro River in the Amazon (Emperaireand Peroni 2007). The highest values of maniocdiversity are found among indigenous popula-tions of the Amazon (Chernela 1986; Colomboet al. 2000; Emperaire and Peroni 2007; Salicket al. 1997).

A single local farmer cultivates 24 varieties,corresponding to 64.9% of the manioc varietiesinventoried in 2011. This farmer is the principalsupplier of manioc propagules among farmers of thecampo-fora. Emperaire and Peroni (2007) discussthe importance of individuals in the managementand maintenance of diversity. In general, verycommon varieties represent less than 10% of thelocal varieties, whereas the rare varieties composethe largest portion of the assortment of varieties(Emperaire and Peroni 2007; Salick et al. 1997).

Table 1. RELATIVE FREQUENCY (N1992 = 27 FARMS;N2011 = 30 FARMS) AND DENSITY (N1992 = 3,741 INDIVIDUALS; N2011= 1,795 INDIVIDUALS) OF MANIOC VARIETIES WITH DENSITY > 2% IN AT LEAST ONE PERIOD; B = BITTER; S = SWEET).

Variety Degree of toxicity

Frequency (%) Density (%)

1992 2011 1992 2011

Mata-Rato b 92.6 36.7 41.0 1.8Rama-Dura s 81.5 50.0 11.0 8.2Liberata s 74.1 23.3 1.0 2.3De-Joãozinho b 44.4 3.3 28.0 0.4Aparecida b 33.3 0.0 3.0 0.0Oiuda s 3.7 43.3 0.0 18.4Cacau s 3.7 26.7 0.3 17.8Pretinha b 0.0 23.3 0.0 26.1Seringueira s 18.5 16.7 3.0 2.7Branca s 0.0 10.0 0.0 4.8

Table 2. SHANNON DIVERSITY INDICES (H’) FOR

BOTH PERIODS 1992 AND 2011.

Period 1992 2011

Direct H’ estimate 1.53 1.52Bootstrap H’ estimate 1.47 1.44Direct variance estimate 0.005 0.007Bootstrap variance estimate 0.004 0.005

b s

317MARCHETTI ET AL.: MANIOC DIVERSITY IN MATO GROSSO2013]

The rare varieties represented 62.5% of thevarieties inventoried in 1992, and in general hadbeen recently introduced (median of two-and-a-half years), thus giving them insufficient time todisseminate. The dynamic of acquisition of newvarieties was very active in the 1990s, mainlyamong the campo-fora communities, where flourproduction was more intense and required theacquisition of roots from other locales, facilitatingthe arrival of allochthonous varieties, whichwere tested by the local farmers in their fields(Amorozo 2000).In 2011, the proportion of rare varieties increased

to 75.9% and the median of introduction time wasfive years. In recent years, the dynamic of circulationand arrival of varieties is more restricted, andtherefore the increase in the proportion of rarevarieties was due to the decrease in agriculturalactivity and successive loss of common varieties at afaster pace than the introduction of new varieties atthe level of the farm.Another variable of the local assortment that

changed during the period was the density ofvarieties in the fields (Table 1). The bittervarieties “Mata-Rato” and “De-Joãozinho,” usedexclusively for the production of manioc flour,occupied the largest cultivated areas in 1992. In2011, these varieties together occupied less than2.2% of the area sampled, and varieties that wererare or nonexistent in 1992 occupied larger

cultivated areas in 2011, such as the bitter variety“Pretinha” and the sweet varieties “Oiuda” and“Cacau.” The toxicity of local varieties wasinformed by the farmers. In general, they consider avariety bitter when the cortex and tuber of the rootsare white and the taste of the cooked root is bitter.The proportion of bitter and sweet varieties

cultivated in the fields, with respect to frequencyas well as density, is directly associated with themarket for manioc flour. Hamlin and Salick(2003) and Fu et al. (2010) showed that changesin the local assortment of species and varieties areinfluenced by the commerce of agriculturalproducts. In the first case, the Yanesha, an indige-nous population in the Peruvian Amazon, developeda system of production for subsistence in combina-tion with production for commerce, maintaininglocal diversity. In the second case, Chinese farmerssubstituted local rice varieties, used mainly forconsumption, with commercial varieties and othercommercialized species. Competition among the twosystems of production (subsistence and commerce)led to the loss of diversity and contributed to greaterfood insecurity, favoring commercial varieties andspecies (Fu et al. 2010).The system of production in the study area

is similar to the indigenous Yanesha system(Hamlin and Salick 2003), in which productionof the varieties for commercial use does nothinder production of the varieties used for localconsumption. In addition, we considered all thevarieties inventoried as landraces (Camacho-Villaet al. 2005). To our knowledge, no improvementprogram was developed in the study area and noimproved variety was officially introduced. If somecommercial variety was introduced via socialnetworks, we could not trace it.In 1992, which was a period of intense

commercialization of manioc flour in the region,more than 70% of the area cultivated withmanioc was occupied by bitter varieties, particu-larly “Mata-Rato” and “De-Joãozinho” (Table 1).The locally-consumed sweet varieties weremaintained in a lower density. According to localfarmers, the bitter varieties were preferred formanioc flour production because they are “drier”and therefore yield more than the sweet varieties.Nevertheless, regional competition led to a

decline in local production of manioc flour, andin 2011 the area planted with bitter varietiescorresponded to about 30% of the fields. Thesweet varieties, like “Oiuda” and “Cacau,” usedfor flour production as well as household con-

Table 3. HUTCHESON’S T-TEST FOR DIFFERENCE INSHANNON DIVERSITY INDICES, USING DIRECT AND

BOOTSTRAP ESTIMATIONS METHODS.

Method Statistic (t value) p-value

Direct estimates 0.03 0.49Bootstrap estimates 0.34 0.37

0

2

4

6

8

10

12

14

1-3 4-6 7-9 10-12 13-15 16 ou +

num

ber o

f far

ms

number of varieties

1992

2011

Fig. 2. Manioc varieties per farm (1992: 27 farms;2011: 30 farms).

318 ECONOMIC BOTANY [VOL 67

sumption, were recruited from the local assort-ment of varieties and occupied the largest areas ofcultivation in 2011. The preference for thesevarieties is in general related to their good tasteand high yield, but some farmers mentioned thepossibility of early harvest and resistance to pests.The variety “Rama-Dura” was widely cultivatedin 2011 due to its flooding tolerance, highdurability in the field, and high productivity forflour (Appendix I).

Peroni and Hanazaki (2002) also observed thesubstitution of bitter varieties with sweet varietiesamong caiçara populations. This shows theflexibility of traditional agriculture (Hamlin andSalick 2003), which adapts to food and commercialneeds through management of the local diversity ofvarieties. This requires on-farm maintenance of thestock of varieties from which the varieties mostappropriate for the current reality will be recruited.

LOCAL RURAL CONTEXT

The area cultivated in the communities wasdrastically reduced from 1992 to 2011 (Table 4).About half of the area under cultivation in 1992 isno longer used for agriculture.Many of the primarilyagricultural properties have undergone a process ofsubdivision among family members and weresold or transformed into summer homes, mainly inthe beira-rio communities, where the potential fortourism has been most developed.

Among the factors that contributed to thedecrease in agricultural activity, those that standout include the aging of the local farmingpopulation (most farmers are over 60 years ofage) and the lack of replacement of family laborto engage in agricultural work; the farmers thatmaintained high diversity in 1992 were the samein 2011, and of the ten farmers in 1992 whomaintained the largest number of varieties ontheir farms (> 10), four had no descendentdedicated to agricultural activities in 2011.However, part of this younger generation stillresides in the communities, but is employedeither in the urban centers or have local non-agricultural jobs in the expanding tourism ser-vices. They occasionally engage in agriculturalwork in their spare time, like part-time farmers(Amorozo 2012).

The proximity of the communities to urbanareas and the ease of highway access encourageyoung people to seek non-agricultural employ-ment and make it possible for people to commute

daily between urban jobs and rural residences.According to the testimonies of local youth, non-agricultural jobs pay better and are less tiring, aswell as representing higher social status thantraditional agricultural work. The lack of incen-tives to practice traditional agriculture inevitablyleads to the reduction in agricultural activity andlack of engagement of young people in the sector,which deters the assimilation of traditionalknowledge, leading to losses in diversity andassociated knowledge in one of the main centersof diversity and domestication of manioc. Thistranslates to an imminent risk for the mainte-nance of local agrobiodiversity.

In both years, the correlation between the sizeof the fields and the number of varieties cultivatedis low (Fig. 3). There was a slight increase in thecorrelation from 1992 to 2011; however, it wasnot statistically significant. Despite the decreasein the field areas, the richness of varieties isstill maintained in the study area. However,the decrease in the area of the fields led to thecultivation of varieties in lower densities, whichposes a threat for diversity. When space is restricted,varieties with no immediately advantageous charac-teristics may be eliminated. Fallow areas may alsobecome scarcer, making it more difficult formicroevolutionary events, like introgression, tooccur, which contribute to increasing maniocdiversity (Emperaire and Eloy 2008; Martins andOliveira 2009).

The trends identified in the study area reflectsocioeconomic changes that took place in Brazilduring this 20-year period. The establishment ofmodern basic infrastructure in the countrysideallowed the development of industrial and ser-vices activities, which in certain regions creatednon-agricultural job opportunities for rural peo-ple. Nevertheless, the trend towards increasingurbanization of the Brazilian population, alreadypresent in the preceding decades, has been carriedfurther, and today’s urban population accounts

Table 4. CULTIVATED AREA IN 1992 AND 2011 (COMMU-NITIES BARREIRINHO AND VARGINHA/ESTRAÍRA).

Period 1992 2011

Domestic units sampled (DU) 20 28Total cultivated area 14.47 ha 6.76 haMean cultivated area/DU 0.72 ha 0.24 haStandard deviation 0.43 ha 0.23 haMedian cultivated area 0.89 ha 0.16 ha

319MARCHETTI ET AL.: MANIOC DIVERSITY IN MATO GROSSO2013]

for 84% of the total. In Mato Grosso State, it was73% in 1991 and 82% in 2010. (IBGE 2010).The ageing of the rural population, due to greateryouth out-migration and fertility decline, has alsoincreased (Camarano and Abramovay 1998;Dutt-Ross et al. 2004; IBGE 2010).In this period, there was considerable expan-

sion of large-scale agribusiness, mainly in thewest-central states. In Mato Grosso, the increasein the area cultivated with export commoditymonocultures was one of the greatest in Brazil;Mato Grosso is at present the greatest soybeanproducer in the country. During the last decade,the area planted with this culture increased by41%, from 4.4 million hectares to 6.2 million(IBGE 2003, 2011). This ongoing expansionforces traditional farmers to migrate, mainly tourban centers, since there are few remainingopen agricultural frontiers. In our study area, theCuiabá Lowland, agribusiness pressure is stillsmall but growing, with more area beingcultivated with soybean and sugarcane. Publicpolicies aimed at supporting small-scale agricul-ture have been implemented nationally in the last

decade, but with little concern for agrobiodiversityconservation.

ConclusionsOn-farm conservation of the high agrobiodiversity

still present in the study area may be threatened if thepresent trend of diminishing/abandonment of agri-culture activity is not reversed. Besides guaranteeingaccess to the land, one of the main issues for themaintenance of these agriculture systems is thecommitment of the younger generations to theircultural and agricultural inheritance. To achieve this,prospects for a better quality of life and access togoods/services in the countryside must be assured.However, it is also necessary to emphasize theimportance of this patrimony and of the traditionalcommunities that maintain it for society at large, dueto their key role in food security as well asfood sovereignty. Public policies focusing onregional rural development must pay specialattention to local traditional management andprocesses that maintain agrobiodiversity. Butthe protection of traditional farming systemsmust be comprehensive, addressing the entire

Fig. 3. Number of varieties found in each field area. The notations on the right stand for the direct estimates ofthe Spearman’s correlations in the respective period bρð Þ, the bootstrap estimates eρð Þ, the z statistic of the adjustedFisher’s test for difference in correlations, and the p-value associated with the test.

320 ECONOMIC BOTANY [VOL 67

food production chain (Emperaire et al. 2008).Small-scale agribusiness, such as local productionof manioc flour, was once important for addingvalue and providing jobs in the area. Smallbusinesses of this nature could become importantagain, and other products could benefit. However, aregional economic order would have to be promot-ed that guarantees the market and prioritizestraditional farmers. Payment for environmentalservices, which is still in the beginning stages inBrazil (Oliveira and Altafin 2008), if expanded toinclude agrobiodiversity conservation services(Krishna et al. 2013; Narloch et al. 2011), couldpromote socioeconomic improvements whilemaintaining on-farm agrobiodiversity.

The Cuiabá lowlands are still home to a largenumber of traditional communities that cultivatemanioc, and they are characterized by a patternof agrobiodiversity similar to that found in thisstudy (Veasey 2011). Recently, a climate riskagricultural zoning law for commercial manioccultivation in the state of Mato Grosso wasapproved by the Ministry of Agriculture, Fisheriesand Livestock; it included a recommendation toplant cultivars registered with the National CultivarRegistry (D.O.U. 2011). This could result toincreased pressure on local agrobiodiversity in thenear future. Thus, it is our recommendation thatareas be identified for additional long-term studieswith the purpose of understanding the dynamics ofthese farming systems and proposing priorities forpolicies aimed at conservation in the region.

AcknowledgmentsWe are especially grateful to the residents of

the communities Barreirinho, Morro Grande,Varginha, and Estraíra for their generosity andparticipation during the field work. We alsothank FAPESP for the financial support(Process nº 2008/03822-3) and the researchscholarship granted to the first author (Processnº 2010/12181-1). The map was made byMichel M. da Silva and the English translationwas by Anne Kepple.

Literature CitedAlvarenga, S. M., A. E. Brasil, R. Pinheiro, and

H. J. H. Kux. 1984. Estudo geomorfológicoaplicado à bacia do Alto Rio Paraguai e pantanaismatogrossenses. Boletim técnico n.1, ProjetoRADAM Brasil, Série Geomorfologia, Salvador.

Alvarez, N., E. Garine, C. Khasah, E. Dounias,M. Hossaert-Mckey, and D. Mckey. 2005.Farmers’ practices, metapopulation dynamics,and conservation of agricultural biodiversityon-farm: A case study of sorghum among theDuupa in sub-sahelian Cameroon. BiologicalConservation 121(4):533–543.

Amorozo, M. C. M. 1996. Um sistema deagricultura camponesa em Santo Antônio doLeverger, Mato Grosso, Brasil. Ph.D. thesis (inAnthropology), University of São Paulo, Brazil.

———. 2000. Management and conservation ofManihot esculenta Crantz. germplasm by tra-ditional farmers in Santo Antônio do Leverger,Mato Grosso State, Brazil. Etnoecológica4(6):69–83.

———. 2012. Diversidade agrícola em umcenário rural em transformação: Será que vaificar alguém para cuidar da roça? In:Agrobiodiversidade no Brasil—Experiências ecaminhos da pesquisa, 2nd. ed., orgs. L. C.Ming, M. C. M. Amorozo, and C. W. Kffuri,377–394. Recife: NUPEEA.

Barelli, M. A., J. R. Seabra, A. M. Amaral, A. P.Moura, A. Nespoli, A. H. Soares, A. M. Oliveira,E. C. Schawinsk, J. C. B. Gonçalves, L. Vescovi,P. H. M. P. Leite, and R. C. Amorim. 2005.Acessos tradicionais de mandioca cultivados emCáceres, MT. Annals of XI Brazilian Congress ofManioc, Campo Grande.

Begossi, A. 1996. Use of ecological methods inethnobotany: Diversity indices. EconomicBotany 50(3):280–289.

Bernard, H. R. 1988. Research methods in culturalanthropology. Newbury Park: SAGE Publishers.

Brasil. 2012. Ministério da Agricultura Pecuáriae Abastecimento, Instituto Nacional deMeteorologia. http://www.inmet.gov.br(01/15/13).

Brush, S. B. 2002. The lighthouse and thepotato: Internalizing the value of crop geneticdiversity. PERI, Working Paper nº 37.

Camacho-Villa, T. C., N. Maxted, M. Scholten,and B. Ford-Lloyd. 2005. Defining andidentifying crop landraces. Plant GeneticResources 3(3):373–384.

Camarano, A. A. and R. Abramovay. 1998. Êxodorural, envelhecimento e masculinização no Brasil.Panorama dos últimos 50 anos. Revista Brasileirade Estudos Populacionais 15(2):45–65.

Chernela, J. M. 1986. Os cultivares de mandioca naárea do Uaupés (Tukâno). In: Suma etnológica

321MARCHETTI ET AL.: MANIOC DIVERSITY IN MATO GROSSO2013]

Brasileira, coord. B. G. Ribeiro, 151–158.Petrópolis: FINEP:Vozes.

Clement C. R., M. De Cristo-Araújo, G.Coppens D’Eeckenbrugge, A. Alves Pereira,and D. Picanço-Rodrigues. 2010. Origin anddomestication of native Amazonian crops.Diversity 2(1):72–106.

Colombo, C., G. Second, and A. Charrier. 2000.Diversity within American cassava germ plasmbased on RAPD markers. Genetics and Mo-lecular Biology 23(1):189–199.

Diário Oficial da União (DOU). 2011. Portaria 128.http://s i s temasweb.agr icul tura .gov.br/s i s legis/act ion/deta lhaAto.do?method=visualizarAtoPortalMapa&chave=12818497(05/31/13).

Dutt-Ross, S., D. C. C. S. C. Sánchez, and A. A.Camarano. 2004. Um estudo sobre afecundidade das mulheres brasileiras na décadade noventa. XIV Encontro Nacional de EstudosPopulacionais, ABEP.

Efron, B. and R. Tibshirani. 1993. An introductionto the bootstrap. Chapman and Hall/CRCMonographs on Statistics and Applied Prob-ability.

Elias, M., G. S. Mühlen, D. Mckey, C. Roa, andC. J. Tohme. 2004. Genetic diversity oftraditional South American landraces of cassava(Manihot esculenta Crantz): An analysis usingmicrosatellites. Economic Botany 58:242–256.

Emperaire, L. and N. Peroni. 2007. Traditionalmanagement of agrobiodiversity in Brazil: A casestudy ofmanioc. Human Ecology 35(6):761–768.

——— and L. Eloy. 2008. The urban area, acenter of agrobiodiversity in the Negro Riverregion (Amazonas, Brazil)? Boletim do MuseuParaense Emílio Goeldi. Ciências Humanas3(2):195–211.

———, L. Van Velthem, and A. G. Oliviera. 2008.Patrimônio cultural imaterial e sistema agrícola:O manejo da diversidade agrícola no Médio RioNegro, Amazonas. 26th Brazilian AnthropologyMeeting, Porto Seguro, Bahia, Brazil.

Eticha, F., W. Sinebo, and H. Grausgruber. 2010.On-farm diversity and characterization of barley(Hordeum vulgare L.) landraces in the high-lands of West Shewa, Ethiopia. EthnobotanyResearch and Applications 8:25–34.

FAO. 1997. The state of the world’s plant geneticresources for food and agriculture. Rome, Italy.

———. 2010. The second report on the state ofthe world’s plant genetic resources for foodand agriculture. Rome, Italy.

FAO, IFAD (Food and Agriculture Organiza-tion, International Fund for AgriculturalDevelopment). 2000. The global cassavadevelopment strategy and implementationplan, V. 1. Proceedings of the validation forumon the global cassava development strategy.

Fraser J. A., A. Alves-Pereira, A. B. Junqueira, N.Peroni, and C. R. Clement. 2012. Convergentadaptations: Bitter manioc cultivation systemsin fertile anthropogenic dark earths andfloodplain soils in Central Amazonia. PLoSONE 7(8):e43636.

Fu, Y., J. Chen, H. Guo, H. Hu, A. Chen, and J.Cui. 2010. Agrobiodiversity loss and livelihoodvulnerability as a consequence of converting fromsubsistence farming systems to commercial plan-tation-dominated systems in Xishuangbanna,Yunnan, China: A household level analysis. LandDegradation and Development 21(3):274–284.

Hamlin, C. C. and J. Salick. 2003. Yaneshaagriculture in the upper Peruvian Amazon:Persistence and change fifteen years down the“road.” Economic Botany 57(2):163–180.

Heerwaarden, J. van, J. Hellin, R. F. Visser, andF. A. van Eeuwijk. 2009. Estimating maizegenetic erosion in modernized smallholderagriculture. Theoretical and Applied Genetics119:875–888.

Instituto Brasileiro de Geografia e Estatística(IBGE). 2003. Produção Agrícola Municipal.<ftp://ftp.ibge.gov.br/Producao_Agricola_Municipal_%5Banual%5D/2003/brasil_uf_grandesregioes/ (03/04/05).

———. 2010. Sinopse do Censo Demográfico.http://www.ibge.gov.br/home/estatistica/populacao/censo2010/tabelas_pdf/Mato_grosso.pdf (9/19/2012).

———. 2011. Produção Agrícola Municipal.ftp://ftp.ibge.gov.br/Producao_Agricola/Producao_Agricola_Municipal_[anual]/2011/pam2011.pdf (9/19/12).

Isendahl, C. 2011. The domestication and earlyspread of manioc (Manihot esculenta Crantz):A brief synthesis. Latin American Antiquity22(4):452–468.

Krishna, V. V., A. G. Drucker, and U. Pascual.2013. Estimating compensation payments foron-farm conservation of agricultural biodiversityin developing countries. Ecological Economics87:110–123.

Léotard, G., A. Duputié, F. Kjellberg, E. J. P.Douzery, C. Debain, J. J. de Granville, and D.Mckey. 2009. Phylogeography and the origin

322 ECONOMIC BOTANY [VOL 67

of cassava: New insights from the northern rimof the Amazon basin. Molecular Phylogeneticsand Evolution 53:329–334.

Lima, D., A. Steward, and B. T. Richers. 2012.Exchange, experimentation and preferences: Astudy on the dynamics of manioc diversity inthe Middle Solimões, Amazonas. Boletim doMuseu Paraense Emílio Goeld, CiênciasHumanas 7(2):371–396.

Marchetti, F. F. 2012. Agricultura tradicional e amanutenção da agrobiodiversidade emcomunidades rurais do município de SantoAntonio do Leverger, MT. Master’s thesis (inPlant Biology), São Paulo State University, Brazil.

Martins, P. S. and G. C. X. Oliveira. 2009.Dinâmica evolutiva em roças de caboclosamazônicos. In: Diversidade biológica e culturalda Amazônia, 2nd ed., I. C. G. Vieira et al., 373–391. Belém: Museu Paraense Emílio Goeldi.

Morais, F. F., R. F. Morais, and C. J. Silva. 2009.Traditional ecological knowledge about plantscultivated by fishermen at Community EstirãoComprido, Pantanal Matogrossense, Brazil.Boletim do Museu Paraense Emílio Goeldi,Ciências Humanas 4(2):277–294.

Nabhan, G. P. 2009. Where our food comes from:Retracing Nikolay Vavilov’s quest to end famine.Washington D.C.: Island Press.

Narloch, U., A. G. Drucker, and U. Pascual. 2011.Payments for agrobiodiversity conservationservices for sustained on-farm utilization ofplant and animal genetic resources. EcologicalEconomics 70(11):1837–1845.

Nassar, N. M. A. 2002. Cassava, Manihot esculentaCrantz, genetic resources: Origin of the crop, itsevolution and relationships with wild relatives.Genetics andMolecular Researches 1(4):298–305.

Oliveira, L. R. and I. G. Altafin. 2008.Proambiente: Uma política de pagamento deserviços ambientais no Brasil. Anais do XLVICongresso da Sociedade Brasileira de Economia,Administração e Sociologia Rural, Rio Branco.

Olsen, K. M. and B. A. Schaal. 1999. Evidenceon the origin of cassava: Phylogeography ofManihot esculenta. Proceedings of the NationalAcademy of Sciences, USA 96:5586–5591.

——— and———. 2001. Microsatellite variationin cassava (Manihot esculenta, Euphorbiaceae)and its wild relatives: further evidence for asouthern Amazonian origin of domestication.American Journal of Botany 88(1):131–142.

Pereira, K. J. C. 2008. Agricultura tradicional emanejo da agrobiodiversidade na Amazônia

Central: Um estudo de caso nos roçados demandioca das Reservas de DesenvolvimentoSustentável Amanã eMamirauá, Amazonas. 2008.Ph.D. thesis (in Ecology of Agroecosystems),University of São Paulo, Brazil.

Peroni, N. and N. Hanazaki. 2002. Current andlost diversity of cultivated varieties, especiallycassava, under swidden cultivation systems inthe Brazilian Atlantic Forest. Agriculture,Ecosystems and Environment 92:171–183.

Pielou, E. C. 1975. Ecological diversity. NewYork: John Wiley.

Resende, A. G., P. S. V. Filho, and M. F. P. S.Machado. 2000. Isozyme diversity in cassavacultivars (Manihot esculenta Crantz). BiochemicalGenetics 38(7/8).

Salick, J., N. Cellinese, and S. Knapp. 1997.Indigenous diversity of cassava: Generation,maintenance, use and loss among the Amuesha,Peruvian Upper Amazon. Economic Botany51(1):6–19.

Sambatti, J. B. M., P. S. Martins, A. Ando. 2001.Folk taxonomy and evolutionary dynamics ofcassava: A case study in Ubatuba, Brazil.Economic Botany 55(1):93–105.

Siqueira, E. M. 2002. História de Mato Grosso:Da ancestralidade aos dias atuais. Cuiabá:Entrelinhas.

Siqueira, M. V. B. M., J. R. Queiroz-Silva, E. A,Bressan, A. Borges, K. J. C. Pereira, J. G. Pinto,and E. A. Viasey. 2009. Genetic characterizationof cassava (Manihot esculenta Crantz) land-races in Brazil assessed with simple sequencerepeats. Genetics and Molecular Biology32(1):104–110.

Valle, T. S. 2002. Coleta de germoplasma deplantas cultivadas. In: Métodos de coleta eanálise de dados em etnobiologia, etnoecologiae disciplinas correlatas, eds. M. C. M Amorozo,L. C. Ming, and S. P. Silva, 129–154. RioClaro: UNESP/SBEE/CNPq.

Veasey, E. A., coord. 2011. Conservação daagrobiodiversidade e dinâmica socioeconômicaentre pequenos agricultores em comunidadesrurais da Baixada Cuiabana em Mato Grosso.Research Report, Fundação de Amparo àPesquisa do Estado de São Paulo (FAPESP).

Wood, D. and J. M. Lenné. 1997. The conservationof agrobiodiversity on-farm: Questioning theemerging paradigm. Biodiversity and Conserva-tion 6:109–129.

Zar, J. H. 2010. Biostatistical analysis. 5th ed. UpperSaddle River, N.J.: Pearson Prentice-Hall.

323MARCHETTI ET AL.: MANIOC DIVERSITY IN MATO GROSSO2013]