Om forskning Molecular anthropology of cassava – a cultural ecology of plant varietal preferences Linley Chiwona-Karltun
Linley Chiwona-Karltun, PhD in International Health, Associate Professor in Rural Development. Researcher and lecturer, Swedish University of Agricultural Sciences, SLU, Uppsala. E-post: [email protected] ”People like Hans Rosling face the criticism of being too superficial, it’s the dilemma of the public intellectual, academics who bridge several disciplines rather than excel at one” Peter Baylor, Baylor College of Medicine, USA on Hans Rosling, Nature 540, 330–333 (15 December 2016) doi:10.1038/540330a.)
Molecular genetics has provided science with innovative tools for increasing food production. One of the legacies that Hans Rosling has left behind is understanding of cassava cyanogenesis and how molecular plant genetics could better contribute to the reversal of the “poverty, population and environment spiral” (PPE-spiral). This requires incorporating appropriate methods and tools for routine use in breeding programmes; with breeders in collaboration with interdisciplinary teams, farmers and more specifically female farmers. In other words, molecular anthropology, the combining of anthropological methods from the social sciences with biochemical methods in surveys. The combination of biological sciences with social sciences, in the understanding of cassava cyanogenesis could rapidly advance and be a cost effective way for understanding farmer varietal preferences and their needs for food security. While funding has improved somewhat, evidence shows that despite the central role that women play in provisioning household food security there remains a severe lack of integration of a critical gendered approach.
Molekylär genetik har försett vetenskapen med innovativa verktyg för att öka matproduktionen. Något Hans Rosling lämnat efter sig är förståelse för hur kassavacyanogenes och molekylär växtgenetik bättre kan bidra till att stoppa den negativa fattigdoms-, befolknings- och miljöspiralen. Det kräver att man inför rutinmässig användning av lämpliga metoder och verktyg i avelsprogram, där uppfödare samarbete med tvärvetenskapliga team och bönder, mer specifikt kvinnliga bönder. Molekylär antropologi är en kombination av antro- pologiska metoder från samhällsvetenskapen och biokemiska undersöknings- metoder. Denna kombinationen kan, när det gäller förståelsen av kassava cyanogenesen, snabbt utvecklas och vara ett kostnadseffektivt sätt att förstå lantbrukarnas sortpreferenser och deras behov av livsmedelssäkerhet. Även om fi nansieringen har förbättrats något råder rådet alltjämt en allvarlig brist när det gäller att se det hela ur ett kritiskt könsperspektiv. Detta trots den centrala roll som kvinnor spelar för att säkra hushållens livsmedelsförsörjning. Socialmedicinsk tidskrift 6/2017 721 Om forskning Introduction continue to determine what roles women can play in crop production Several studies continue to show that and other functions (Quisumbing et there are differences in how men and al., 2014). This is further compoun- women select cassava varieties based ded by lack of participation as influ- on their various needs and preferen- enced by differential access to chain ces (Chiwona-Karltun et al., 2015, functions, services and resources, and Masamha et al., 2017, Christinck et by gender-related power disparities in al., 2017). Furthermore, evidence agro-commodities (Nakazibwe and shows that despite the central role that Pelupessy, 2014). In this paper, I revisit women play in provisioning house the earlier work that I conducted to- hold food security there remains a gether with Hans Rosling on cassava severe lack of integration of a critical varietal plant preferences in Malawi to gendered analysis in the total accu- contribute to the ongoing debate on mulated research. This is particularly how gender determines the relative glaringly absent from commodity or importance of varietal traits and the value chains research (Andersson et selection of cultivars particularly for al., 2016, Dunaway, 2014). In his semi- household food security. While much nal work on molecular anthropology, work has been conducted on cassava Hans Rosling stated the following: since then, clearly there remains much work to be done when it comes “the mostly female farmer in the poorest to cassava, household food security communities can identify problems and and women’s participation as well as possible solutions for farming systems decision-influencing in cassava value researchers with downstream researchers. chains (Masamha et al., 2017). She can also contribute to upstream A recent review on gender diffe- research with a wealth of accumulated rential farmer varietal preferences, knowledge of the biological system she showed that men tend to focus more operates if the visiting researcher possess on production and market-related methods for collection of this biological traits while women focus more on knowledge. My limited experience of production and end-use related traits poor agricultural communities in Africa (Christinck et al., 2017). It is surpri- indicates that there, in addition to the sing that almost two decades later, research stream continuum is a place for these findings are no different from some rain-research” (Sobral 1996:316). our earlier work on farmer cassava preferences (Chiwona-Karltun et al., In my many years of research on and 1998). In the conclusions of the re- with cassava, I have come across view by Christinck et al., the authors few studies dedicated to identifying emphasize the importance of deepe- problems and possible solutions for ning our understanding of gender- mostly female farmers. Overwhelming specific differences and that such evidence shows that patriarchal, insights would aid to assist plant social, and cultural stereotypes breeders towards addressing gender-
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While much work has been conducted on cassava there remains much work to be done when it comes to household food security and women’s participation as well as decision-influencing in cassava value chains. Field photography specific preferences for varietal traits. ment spiral (PPE-spiral). The authors end by stating that this In his earlier studies on konzo, would require appropriate methods Rosling and colleagues, (Rosling et al., and tools for routine use in breeding 1993) describe the causal mechanisms programmes; breeders in collabora- behind human diseases induced by tion with interdisciplinary teams and dietary cyanide exposure from con- farmers. In other words, molecular sumption of cassava. It is during these anthropology. studies that Rosling realizes that the combination of clinical obser The origins of vations with biological phenomena molecular anthropology would reveal deeper understanding of contextual problems such as In his chapter in the book edited konzo. Rosling was a pioneer in his by Bruno Sobral in 1992 titled “the time, combining anthropological impact of plant molecular genetics” methods from the social sciences with (Rosling, 1996), Hans Rosling persua- biochemical methods in surveys, best sively outlines how molecular genetics described as molecular anthropology. had provided science with innovative Molecular anthropology is a concept tools for increasing food production. that was first defined by Zukerland The story that Hans Rosling tells (1963). The term was used to deter is that of cassava cyanogenesis and mine amino acid sequence of serum how molecular plant genetics could proteins in prehistoric human evolu- better contribute to the reversal of tion. A medical doctor by training, the “poverty, population and environ Rosling was intrigued by the onset Socialmedicinsk tidskrift 6/2017 723 Om forskning
Removal of bitterness and toxicity in cassava roots soaking and fermentation in earthenware pots in Nkhata-Bay, Malawi. Field photography of the disease konzo that had causal knowledge or evidence from fallacy. links with the food crop cassava. When Hans Rosling first introduced Rosling’s encounter with cassava in the concept of molecular anthropology Mozambique is what lead Rosling in understanding cassava cyanogensis into the field of ethnobotany. Other he dared to term it a marketing trick. authors in this special issue have described the Mozambique story. “a marketing trick to convey old wisdom According to the Oxford dictionary, already conveyed by Louis Pasteur, in the ethnobotany is the scientific study of field of observation, chance favours the the traditional knowledge and customs prepared mind” (Sobral, 1992:317) of a people concerning plants and their medical, religious, and other uses However, history was to show that, it (https://en.oxforddictionaries.com/ was the beginning of a long-term buil- definition/ethnobotany). Rosling had ding of human capacities of African figured out that the combination of scientists at doctoral education level biological sciences with social sciences, as well as post-doctoral level in the in the understanding of cassava cyano field of cassava research and develop- genesis could rapidly advance and be ment. The ground breaking work by a cost effective way for understanding one of the leading cassava geneticist poor farming communities and their in the world, Martin Fregene, would pressing needs for food security. The culminate in the mapping of the underlying premise being to sort out cassava genome (Fregene et al., 1997, 724 Socialmedicinsk tidskrift 6/2017 Om forskning
Nursery discussion. Farmer to farmer varietal selection discu- Field photography ssions Domasi CMRTE farmers visiting Mulanje farmers 2002. Field photography
Fregene et al., 2001). While the app- improves shelf-life but also that bit- lication of molecular anthropology terness and toxicity in cassava roots methodology would firstly result in can be removed through processing explaining in-depth why farmers, (Coursey, 1973, Dufour, 1989, Hahn, especially women, preferred bitter 1989, Nweke, 1994, Chiwona-Karltun cassava cultivars. Secondly, applica- et al., 2000). Any shortcuts or inter- tion of molecular anthropology show- ruptions in of the processing sequence ed that farmers ethno-classification of due to extreme poverty, food shor- varieties into bitter and cool cassava tages may result in high residuals of cultivars corresponded to a genetic cyanogenic glucosides in consumed sub-division of the typical genotypes products leading to dietary cyanogen of the most common cultivars, with exposure. It is these types of exposu- four-fold higher cyanogenic gluco- res that may cause acute poisonings side levels in the bitter cultivars. We and have been implicated as a causa- clearly showed that women farmers tive factor in neurological disorders grasp sufficiently the genetic diversity (Tylleskär et al., 1992). of cassava with regard to cyanogenesis Thus to get an indepth understan- to simultaneously benefit from it and ding of the rationale for why farmers avoid its dangers. in Malawi, particularly women, pre- ferred to grow cultivars with bitter Cassava Toxicity and toxic roots we used a combina- and Food Security tion of explorative survey methods (Chiwona-Karltun et al., 1998). The Historically, it has been found that findings were extremely revealing, in areas where cassava constitutes a emphasizing for the first time that main staple crop, farmers preferen while advances in molecular gene- tially grow varieties that are both tics had advanced and acyanogenic bitter and toxic (Jones, 1959, Nwe- cassava, that is toxic free cassava ke and Bokanga, 1994, Purseglove, could be bred, this scientific achieve 1968). There is ample documenta- ment was neither perceived as a prio- tion showing that processing not only Socialmedicinsk tidskrift 6/2017 725 Om forskning
Above: Farmer varietal selection discussions. Right: Irrigation, intercropping, Domasi.
Tasting the tip of a cassava root to determine bitterness and ethnobotany classification Field photography rity or benefit by the farmers. They and development agenda. However, were three main categories of fin- of all the findings, the most important dings for the farmers rationale and finding was the fact that farmers, men preference for bitter cassava namely: and women regarded the crop cassava 1) protection from human theft and to be two different types of crops, the vermin; 2) yield explained by the bitter and toxic and the cool and non- bitterness and 3) end-product quality toxic. The richness of the local langu- both of the roots as well as the cassava age that farmers, especially women, leaves (Chiwona-Karltun et al., 1998). used to describe minute differences Cassava leaves is something that between very bitter, bitter to slightly grossly have been marginalized in the bitter was fascinating. Not least scientific literature as well as research because in much of the discussions
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Interviewing farmers. Field photography with key-informants, that is scientists, local custom. The very same cassava farmers were regarded as sometimes, root that the farmer tasted were taken “confusing” issues. How could one to the laboratory where a trained be certain that farmers knew for sure taste panel and chemical analysis was what they were talking about, that is undertaken to determine the cyano- separating knowledge from super genic glucoside equivalent. This study stition as Rosling had described in his entailed 492 cassava roots, classified seminal paper on molecular anthro- as bitter and toxic or cool and non- pology (Rosling, 1996). toxic. Farmer’s distinction of the roots into these categories predicted cyano Molecular anthropology genic glucoside levels and tasting of in practice the root greatly enhanced this pre- diction. The scoring of bitterness Studies had successfully been under by the trained taste panel correlated taking to examine the detoxification strongly with glucoside levels sugges- of cassava as described above, but ting that cyanogenic glucoside confer hitherto, there were no studies combi- the bitter taste (Chiwona-Karltun ning survey social science qualitative et al., 2004). In order to verify how interviews with biochemical studies on well women farmers comprehen- the same specimen. In an unparalleled ded cassava genetics in dealing with study, interviews were conducted with cassava cyanogenesis in this complex women farmers to ascertain the name system, we enlisted molecular markers of each cultivar, the predicted taste to show that farmers knowledge about and the actual taste of the root as per Socialmedicinsk tidskrift 6/2017 727 Om forskning
Cassava sold at the market. Field photography a specific named cultivar had a typi- Consequences for future cassava cal genotype of that cultivar (Mkum- research – a cultural ecology of bira et al., 2003). Furthermore, the food preference farmer’s ethno-classification of their It is unequivocal, as reflected in the cassava cultivars into bitter or cool quote at the beginning, that Hans was not random but based on in- Rosling’s contribution to cassava re- depth morphological and cyanogenic search, particularly in the novel field experience. Clearly, the combination of combining the use of social science of taking into account women far- survey methods with biochemical mers’ knowledge, the environmental and molecular genetic studies, has context and advances in molecular contributed significantly to a better genetics could contribute towards understanding of how resource poor improving household food security African women farmers try to ensure and even other indirect benefits. In household food security. This was way so doing, a more nuanced understan- before funding for “orphan crops” ding of the what, how and why could like cassava were identified as target better inform scientists, particularly crops for funding by major donors. breeders on what preferences farmers While funding has improved some are likely to regard as important and what, it is nevertheless disconcer- thus increase adoption of improved ting that evidence shows that despite bred cassava materials (Kizito et al., the central role that women play in 2007, Chiwona-Karltun et al., 2015). provisioning household food secu- rity there is a severe lack of integra- 728 Socialmedicinsk tidskrift 6/2017 Om forskning tion of a critical gendered approach Chiwona-Karltun, L., Nyirenda, D., Mwansa, C. in the total accumulated research N., Kongor, J. E., Brimer, L., Haggblade, S. & Afoakwa, E. O. 2015. Farmer Preference, (Dunaway, 2014, Masamha et al., Utilization, and Biochemical Composition of 2017). The recent review showing that Improved Cassava (Manihot esculenta Crantz) men tend to focus more on produc- Varieties in Southeastern Africa. Economic Botany, 69, 42-56. tion and market-related traits while women focus more on production Chiwona-Karltun, L., Tylleskär, T., Mkumbira, J., and use-related traits (Christinck et Gebre-Medhin, M. & Rosling, H. 2000. Low dietary cyanogen exposure from frequent al., 2017), findings much similar to consumption of potentially toxic cassava in our earlier work on reasons for use of Malawi. International Journal of Food Scienc- bitter cassava (Chiwona-Karltun et al., es and Nutrition, 51, 33-43. 1998) informs that there is a sense of Christinck, A., Weltzein, E., Rattunde, F. & Ash- urgency in doing things differently. by, J. 2017. Gender differentiation of farmer Enlisting a broader understanding of preferences for varietal traits in crop improve- the cultural ecology of food preferen- ment: evidence and issues. CGIAR Gender and Agriculture Research Network. Ali, Colombia: ces i.e. taking into account environ CIAT. mental and cultural issues, with specific reference to cassava varietal Coursey, D. G. 1973. Cassava as food: toxicity and technology. In: Nestle B, M. R. (ed.) Chronic traits and end-use preference with cassava toxicity. Ottawa, Canada: International gender in mind is paramount. Today Development Research Centre. more than ever before, there is the need to apply molecular anthropology Dufour, D. 1989. Effectiveness of cassava detoxifi- cation techniques used by indigenous peoples methodology in deepening our under- in NW Amazonia. Intersciencia, 14, 86-91. standing as well as embracing trans- disciplinary research to find evidence- Dunaway, W. A. 2014. Bringing Commodity Chain Analysis Back to its World-Systems Roots: based solutions for food security. Rediscovering Women’s Work and Households. Journal of World-Systems Research, 20, 64. References Fregene, M., Angel, F., Gomez, R., Rodriquez, F., Andersson, K., Lodin, J. B. & Chiwona-Karltun, Chavarriaga, P., Roca, W., Tohme, J. & Bonier L. 2016. Gender dynamics in cassava leaves bale, M. 1997. A molecular genetic map of value chains: The case of Tanzania. Journal of cassava (Manihot esculenta Crantz). Theoreti- Gender, Agriculture and Food Security, 1. cal and Applied Genetics, 95, 431-441.
Chiwona-Karltun, L., Brimer, L., Saka, J., Mhone, Fregene, M., Okogbenin, E., MBA, C., Angel, F., A., Mkumbira, J., Johansson, L., Bokanga, M., Suarez, M. C., Janneth, G., Chavarriaga, P., Mahungu, N. & Rosling, H. 2004. Bitter taste Roca, W., Bonierbale, M. & Tohme, J. 2001. of cassava roots correlates with cyanogenic Genome mapping in cassava improvement: glucoside levels. Journal of the Science of Food Challenges, achievements and opportunities. and Agriculture, 84, 581-590. Euphytica, 120, 159-165.
Chiwona-Karltun, L., Mkumbira, J., Saka, J., Hahn, S. 1989. An overview of African traditional Bovin, M., Mahungu, N. & Rosling, R. 1998. cassava processing and utilisation. Outlook on The importance of being bitter - a qualitative Agriculture, 18, 110-118. study on cassava cultivar preference in Malawi. Ecology of Food and Nutrition, 37, 219-245. Jones, W. 1959. Manioc in Africa, Stanford, Stanford University Press.
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Kizito, E. B., Chiwona-Karltun, L., Egwang, T., the first international scientific meeting of the Fregene, M. & Westerbergh, A. 2007. Genetic Cassava Biotechnology Network, 1993 Carta- diversity and variety composition of cassava on gena, Colombia, 25-28 Aug, 1992. CIAT, Cali, small-scale farms in Uganda: an interdiscipli- Colombia. nary study using genetic markers and farmer interviews. Genetica, 130, 301-318. Tylleskär, T., Banea, M., Bikangi, N., Cooke, R., Poulter, N. & Rosling, H. 1992. Cassava cyano- Masamha, B., Thebe, V. & Uzokwe, V. N. E. gens and konzo, an upper motoneuron disease 2017. Unlocking the Household ‘Black found in Africa. Lancet, 339, 208-211. Box’: A Gendered Analysis of Smallholder Farmers' Participation in the Cassava (Manihot esculenta crantz) Value Chain in Tanzania. Journal of International Develop- ment.
Mkumbira, J., Chiwona-Karltun, L., Lagercrantz, U., Mahungu, N. M., Saka, J., Mhone, A., Bokanga, M., Brimer, L., Gullberg, U. & Rosling, H. 2003. Classification of cassava into ‘bitter’and ‘cool’in Malawi: From farmers’ perception to characterisation by molecular markers. Euphytica, 132, 7-22.
Nakazibwe, P. & Pelupessy, W. 2014. Towards a gendered agro-commodity approach. Journal of World-Systems Research, 20, 229.
Nweke, F. 1994. Cassava processing in Sub-Saharan Africa: Implications for expanding cassava production. Outlook on Agriculture, 23, 197- 205.
Nweke, F. & Bokanga, M. 1994. Importance of cassava processing for production in Sub- Saharan Africa. Acta Horticulturae, 375, 401- 412.
Purseglove, J. 1968. Tropical crops: dicotyledons., London, Longmans, Green.
Quisumbing, A. R., Rubin, D., Mandre, C., Waithanji, E., Van Den Bold, M., Olney, D. & Meinzen-Dick, R. S. 2014. Closing the gender asset gap: Learning from value chain develop- ment in Africa and Asia.
Rosling, H. 1996. Molecular anthropology of cassava cyanogensis. In: Sobral, B. (ed.) The impact of plant molecular genetics. La Jolla,: Birkhauser.
Rosling, H., Mlingi, N., Banea, M. & Tylleskär, T. Causal mechanisms behind human diseases induced by cyanide exposure from cassava. In: Roca, W. & Thro, A., eds. Proceedings of
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