Chapters 5.40
5.40 Marama bean as a subsistence and cash crop for smallholder farmers facing the impacts of climate change
Reid Sampson, University of Guelph, Canada
Suggested citation for this chapter.
Sampson,R. (2022) Marama bean as a subsistence and cash crop for smallholder farmers facing the impacts of climate change, In Farmpedia, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. http://www.farmpedia.org
Marama Bean Background Information
Marama bean (Tylosema esculentum) is a wild legume food crop that is indigenous to Southern Africa, found primarily in the Kalahari Desert, Namibia, Botswana and the northwestern region of South Africa (Faria et al., 2011). Forming a part of the indigenous population’s diet, marama bean is considered underutilized in the global food market, despite its vast nutritional and socio-economic value (Holse et al., 2010). Due to this underutilization, marama bean has remained largely unmodified by humans, resulting in a crop adapted to its natural environment, but providing little yield due to lack of improvement (Cullis et al., 2018). Suitable to be grown in environments which experience little rainfall and temperatures of upwards of 37oC, marama bean has vast potential to improve food security for smallholder farmers (Holse et al., 2010); operating as a buffer against the negative effects of climate change in drought-afflicted areas.
Growth of marama bean
Native to the Kalahari Desert, most marama bean is found growing in the wild (Cullis et al., 2018), preferring neutral and alkaline sandy soils which are prevalent in the African subtropics (Cullis et al., 2019). Receiving approximately 250-500 mm of rain annually, the crop is adapted to extreme environments, often growing where no other vegetation flourishes (Cullis et al., 2019). The plant is a creeper that spreads vines across the ground at a length of up to 6 meters (Cullis et al., 2019). These vines produce bilobed leaves which open in the morning, and fold together later in the afternoon when the sun is at its highest; reducing photodamage (Cullis et al., 2019). Marama bean is able to survive in such harsh conditions due to a number of drought-resistant mechanisms which include reducing the amount of leaves and stems it grows depending on moisture conditions, as well as producing a tuberous root (Cullis et al., 2018). This tuberous root operates as a starch and water reservoir, which the plant can access in times of prolonged drought (Cullis et al., 2018). An old tuber can weight upwards of 250 kg and hold 90% of its weight in water (Cullis et al., 2018). The crop prefers cold and dry winters, as the tuberous root beings to rot in moist soils (Cullis et al., 2019). An additional drought avoidance mechanism is the tap root, which penetrates deep within the sand in search of moisture, providing the plant with a steady supply of water (Cullis et al., 2018). Marama bean is a self-incompatible outcrossing crop, meaning it is unable to pollinate itself (Cullis et al., 2019). This prevents inbreeding, allowing farmers to target specific traits at each harvest to determine what to plant the following year (Muñoz-Sanz et al., 2020). This feature additionally protects farmers from pests and disease, as marama bean is unable to be grown as a homogenous monoculture (Cullis et al., 2019).
Nutrition
The primary nutritional value that comes from the marama bean is the high protein and fat/oil content of its seeds (Holse et al., 2010). The seed fat/oil concentration ranges from 35 – 48% of its dry matter, while the protein can account for approximately 30-39% of dry matter (Holse et al., 2010). These values give the marama seeds a protein level comparable to that of soybeans (Glycine max) (33-46%), while providing approximately the same amount of fat/oil as peanuts (Arachis hypogaea) (45-55%) (Holse et al., 2010). The seeds contain all essential amino acids, and provide a variety of macro-nutrients including calcium, magnesium, phosphate and potassium (Holse et al., 2010). Staying edible for years after harvesting due to a tough outer shell and low water content, marama bean seeds are an ideal famine food (Holse et al., 2010). The seeds are not the only edible component of the crop. Marama bean’s primary water and starch storage organ, the tuber, is commonly consumed as a source of carbohydrates and water, especially in times of drought (Cullis et al., 2019). The tuber also has a very high protein value, comprising approximately 9% of its dry weight (Cullis et al., 2018). An interesting feature of marama bean is its lack of root nodules as a habitat for atmospheric nitrogen fixation, despite it being a member of the legume family (Fabaceae) and despite its seeds and tuber having a high protein content, consistent with biological nitrogen fixation (Cullis et al., 2018).
Planting/Gathering
Today, marama bean remains a wild plant that has been largely ignored by international organizations due to the lack of economic importance in the global market (Cullis & Kunert, 2016). Increased international research and the deliberate cultivation of this crop are essential if it is to be utilized as a cash and food crop for smallholder farmers (Faria et al., 2011). Since the first attempt to cultivate the crop in Botswana in 1984, there has been approximately a dozen research projects focusing on its potential for commercialization and cultivation (Faria et al., 2011). Marama bean is a perennial plant, meaning its seeds re-sprout every year, growing from the underground tuber (Cullis et al., 2019). This is advantageous for smallholder farmers, as they save money on the cost of planting. In addition to the economic benefits of having a crop that provides seeds every harvest, the tuber from which the crop grows from can also be harvested for economic yield (Cullis et al., 2019). Marama seeds do not begin to be produced until the second year after planting, resulting in a delay with respect to food production (Cullis et al., 2018). Agricultural practices that have been studied include separating the crop into two groups; one which continually grows beans annually, while the other group is harvested for their tubers (Cullis et al., 2019). With respect to the gathering of wild marama bean, unsustainable farming practices include harvesting the beans before they can ripen, which damages the plant’s ability to regenerate (Faria et al., 2011).
Practical issues
Despite the marama bean’s huge potential as a staple food crop, it remains underutilized, primarily due to the lack of mainstream research and development (Cullis & Kunert, 2016). This is a result of only a handful of samples being analyzed with respect to the crops’ chemical composition (Holse et al., 2010). Due to the small quantities of seeds which are gathered at any given time, marama bean consumption is confined to the local level (Faria et al., 2011). This confinement to the local level is also exacerbated by the lack of resources that sellers possess to transport their harvest over long distances (Faria et al., 2011). The seeds’ high concentration of protein and fat/oil makes marama bean a great addition to a smallholder farmer’s diet, and as a result it holds high socio-economic value as a food and cash crop locally (Holse et al., 2010). Smallholder farmers have already been observed selling marama bean to nearby villages, usually in the form of raw or roasted seeds (Faria et al., 2011). The price of marama bean in local markets fluctuate depending on the availability of the wild crop in relation to the community, with prices dropping as supply increases during the April gathering season (Faria et al., 2011). In 2008, raw seeds were found to have been selling in local markets in Namibia for approximately 2-3 N$/cup, or the equivalent of 0.13 - 0.20 cents US per cup (Faria et al., 2011). When roasted and unshelled, the seeds can sell for upwards of 5 N$/cup, or 0.33 cents US per cup (Faria et al., 2011). Marama bean seeds are commonly sold whole but can also be pounded into a flour or turned into a butter to improve its economic value in local markets (Faria et al., 2011). Additional research that needs to be conducted includes determining the presence of toxins in the raw seeds (Holse et al., 2010) and leaves as forage, as well as methods of improving the crop’s annual seed production. In order to begin the process of breeding for better yields, resources must first be allocated into determining the types of insects that pollinate the crop, as this is currently unknown (Cullis et al., 2019).
Additional Links
https://www.nap.edu/read/11763/chapter/15#237 A chapter on marama bean from the book “Lost Crops of Africa: Volume II: Vegetables”.
https://www.youtube.com/watch?v=DxNTkYtSFYw A video discussing the implementation of marama bean to improve food security in Africa.
https://www.echocommunity.org/en/resources/9e6b7a74-93c9-428e-928a-00b6dcb65d63 An article that looks more in depth at the cultivation, nutrition and preparation of marama bean.
https://www.youtube.com/watch?v=XWKOyGH0XY8 A video of a research project done in Africa by Case Western Reserve University, looking into tuber growth and size.
http://www.nbri.org.na/sections/economic-botany/INP/sectors/Marama-bean An article posted by the National Botanical Research Institute giving an overview of the environments marama bean grows in, its nutritional value, growing cycle and potential as a buffer against climate change.
http://tropical.theferns.info/viewtropical.php?id=Tylosema+esculentum An article depicting the various ways marama bean can be prepared including how to cook the seeds, the various uses of the bean’s oil, as well as the uses of different aged tubers.
https://www.ebay.com/itm/World-rarest-Tylosema-esculentum-marama-bean-green-gold-1-rare-seed-/183896093148 An eBay offering of someone selling marama bean seeds.
https://www.youtube.com/watch?v=6VXgcsmSyF0 An extremely informative video by the “Morama Engaged” project discussing the future of marama bean production and cultivation, different products that can be made out of the crop, as well as the potential health benefits it holds.
References
1. Cullis, C., Chimwamurombe, P., Barker, N., Kunert, K., & Vorster, J. (2018). Orphan Legumes Growing in Dry Environments: Marama Bean as a Case Study. Frontiers in Plant Science, 9, 1199. https://www.frontiersin.org/articles/10.3389/fpls.2018.01199/full
2. Cullis, C., & Kunert, K. J. (2016). Unlocking the potential of orphan legumes. Journal of Experimental Botany, 68(8), 1895-1903. https://academic-oup-com.subzero.lib.uoguelph.ca/jxb/article/68/8/1895/2731367
3. Cullis, C., Lawlor, D. W., Chimwamurombe, P., Bbebe, N., Kunert, K., & Vorster, J. (2019). Development of marama bean, an orphan legume, as a crop. Food and Energy Security, 8(3), 1193-1212. https://www-proquest-com.subzero.lib.uoguelph.ca/docview/2272605983/B7EEC2D4FAD44687PQ/9?accountid=11233
4. Faria, M., Mabaya, E., & Jordaan, D. (2011). Markets for marama beans in southern Africa: Linking sustainable products with sustainable livelihoods. Development Southern Africa, 28(4), 477-492. https://www-tandfonline-com.subzero.lib.uoguelph.ca/doi/full/10.1080/0376835X.2011.605566
5. Holse, M., Husted, S., & Hansen, Å. (2010). Chemical composition of marama bean (Tylosema esculentum) - A wild African bean with unexploited potential. Journal of Food Composition and Analysis, 23(6), 648-657. https://www-sciencedirect-com.subzero.lib.uoguelph.ca/science/article/pii/S0889157510001146?via%3Dihub
6. Muñoz-Sanz, J., Zuriaga, E., Cruz-García, F., McClure, B., & Romero, C. (2020). Self-(In)compatibility systems: Target traits for crop-production, plant breeding, and biotechnology. Frontiers in Plant Science, 11, 195. https://www.frontiersin.org/articles/10.3389/fpls.2020.00195/full