by William Preston –
Climate change is a reality, and global food production systems could be at a great risk [1]. Agricultural land all over the world is likely to experience major changes in temperature and water availability [2,3,4]. What is more worrying is that mass produced crops such as maize and wheat have a very low genetic diversity, which means they are unlikely to adapt well to changes in environmental conditions; therefore, crop yields and food security will decrease [2,5,6]. Fortunately, it’s not all doom and gloom and scientists such as from [2] are working out solutions.
Heider et al [2] conducted an experiment to assess how climate change may affect productivity of sweet potato crops [2]. Here’s why sweet potatoes are great. As well as sweet potatoes already being relatively tolerant to drought and other climate stresses, they have a great genetic diversity, which means there are potential characteristics in the many varieties that could make them adaptable to climate change [7,8,9,10,11]. Another great feature of sweet potatoes is that they are highly nutritious, full of macro and micro-nutrients – they are even considered a superfood [12]. It is also worth mentioning that the planting and harvesting of sweet potatoes is relatively flexible and requires less labour than other crops [13].
Harvesting at Green Gulch Farm in California. Image: Joshua Wickerham, CC BY-SA 2.0 via Wikimedia Commons
The experiment took place in Peru [2]. They tested the heat stress tolerance of 1973 different varieties of sweet potato while trying to identify which traits should be focused on when selectively breeding sweet potatoes to cope with global temperature increase [2]. The 1973 varieties of sweet potato were planted in both a season of heat stress (HS) and a season with non-heat-stress (NHS) [2]. 120 days after they were planted, root and foliage yield were measured [2]. As would be expected, the sweet potatoes under NHS conditions gave much higher yields on average than those under HS conditions however, what is important is that 132 varieties achieved above average yields under HS conditions [2]. This is promising news and I believe data like this can be used to make farming in developing countries, where crops are increasingly experiencing heat stress, more efficient [3]. This would improve people’s livelihoods and create stronger food security as well as potentially eliminate stresses on the environment exhibited by unsustainable farming techniques – better crop yields mean less land is needed to be cleared for farming [14].
It should also be highlighted that 65.9% of the plants that performed well under heat stress conditions were traditional cultivators and it must be considered how wild relatives of sweet potato could contribute resistant genes and improve food security [2,15]. This relates to the importance of biodiversity and conservation of natural ecosystems, which are reservoirs of an abundance of species with potential benefits to humankind. Hopefully further research in agrodiversity will enable humans to reduce their impact on the environment, by using more efficient crops, and also put an end to world hunger.
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References
[1] Norris, J., Allen, R., Evan, A. et al. (2016) Evidence for climate change in the satellite cloud record. Nature 536, 72–75.
[2] Heider, B., Struelens, Q., Faye, É., Flores, C., Palacios, J.E., Eyzaguirre, R., de Haan, S. and Dangles, O. (2020) Intraspecific diversity as a reservoir for heat-stress tolerance in sweet potato. Nature Climate Change, pp.1-6.
[3] Zhao, C., Liu, B., Piao, S., Wang, X., Lobell, D.B., Huang, Y., Huang, M., Yao, Y., Bassu, S., Ciais, P. and Durand, J.L. (2017) Temperature increase reduces global yields of major crops in four independent estimates. Proceedings of the National Academy of Sciences, 114(35), pp.9326-9331.
[4] Lobell, D.B., Schlenker, W. and Costa-Roberts, J. (2011) Climate trends and global crop production since 1980. Science, 333(6042), pp.616-620.
[5] Nicotra, A. B. et al. (2010) Plant phenotypic plasticity in a changing climate. Trends Plant Sci. 15, 684–692.
[6] Mercer, K.L. and Perales, H.R. (2010) Evolutionary response of landraces to climate change in centers of crop diversity. Evolutionary applications, 3(5‐6), pp.480-493.
[7] Gibson, R. (2009). Review of Sweetpotato Seed System in East and Southern Africa. International Potato Center.
[8] Yang, Z., Zhu, P., Kang, H., Liu, L., Cao, Q., Sun, J., Dong, T., Zhu, M., Li, Z. and Xu, T. (2020) High-throughput deep sequencing reveals the important role that microRNAs play in the salt response in sweet potato (Ipomoea batatas L.). BMC genomics, 21(1), pp.1-16.
[9] Warren, J.F. (2018) Typhoons and droughts: Food shortages and famine in the Philippines since the seventeenth century. International Review of Environmental History, 4(2), pp.27-44.
[10] Challinor, A.J., Watson, J., Lobell, D.B., Howden, S.M., Smith, D.R. and Chhetri, N. (2014) A meta-analysis of crop yield under climate change and adaptation. Nature Climate Change, 4(4), pp.287-291.
[11] Roullier, C., Duputié, A., Wennekes, P., Benoit, L., Bringas, V.M.F., Rossel, G., Tay, D., McKey, D. and Lebot, V. (2013) Disentangling the origins of cultivated sweet potato (Ipomoea batatas (L.) Lam.). PLoS One, 8(5), p.e62707.
[12] Woolfe, J.A. (1992) Sweet potato: an untapped food resource. Cambridge University Press.
[13] Jayne, T.S., Villarreal, M., Pingali, P.L. and Hemrich, G. (2004) Interactions between the agricultural sector and the HIV/AIDS pandemic: Implications for agricultural policy (No. 1094-2016-88102).
[14] Verma, A.K. (2017) IMPACTS OF UNSUSTAINABLE FARMING ON ENVIRONMENT. SN Page No., p.59-62
[15] Khoury, C. K. et al. (2015) Distributions, ex situ conservation priorities, and genetic resource potential of crop wild relatives of sweetpotato [Ipomoea batatas (L.) Lam., I. series Batatas]. Front. Plant Sci. 6, 251.
