Abstract
Cassava or manioc (Manihot esculenta Crantz), a perennial shrub of the New World, currently is the sixth world food crop for more than 500 million people in tropical and sub-tropical Africa, Asia and Latin America. It is cultivated mainly by resource-limited small farmers for its starchy roots, which are used as human food either fresh when low in cyanogens or in many processed forms and products, mostly starch, flour, and for animal feed. Because of its inherent tolerance to stressful environments, where other food crops would fail, it is often considered a food-security source against famine, requiring minimal care. Under optimal environmental conditions, it compares favorably in production of energy with most other major staple food crops due to its high yield potential. Recent research at the Centro Internacional de Agricultura Tropical (CIAT) in Colombia has demonstrated the ability of cassava to assimilate carbon at very high rates under high levels of humidity, temperature and solar radiation, which correlates with productivity across all environments whether dry or humid. When grown on very poor soils under prolonged drought for more than 6 months, the crop reduce both its leaf canopy and transpiration water loss, but its attached leaves remain photosynthetically active, though at greatly reduced rates. The main physiological mechanism underlying such a remarkable tolerance to drought was rapid stomatal closure under both atmospheric and edaphic water stress, protecting the leaf against dehydration while the plant depletes available soil water slowly during long dry periods. This drought tolerance mechanism leads to high crop water use efficiency values. Although the cassava fine root system is sparse, compared to other crops, it can penetrate below 2 m soil, thus enabling the crop to exploit deep water if available. Leaves of cassava and wild Manihot possess elevated activities of the C4 enzyme PEP carboxylase but lack the leaf Kranz anatomy typical of C4 species, pointing to the need for further research on cultivated and wild Manihot to further improve its photosynthetic potential and yield, particularly under stressful environments. Moreover, a wide range in values of K m (CO2) for the C3 photosynthetic enzyme Rubisco was found among cassava cultivars indicating the possibility of selection for higher affinity to CO2, and consequently higher leaf photosynthesis. Several plant traits that may be of value in crop breeding and improvement have been identified, such as an extensive fine root system, long leaf life, strong root sink and high leaf photosynthesis. Selection of parental materials for tolerance to drought and infertile soils under representative field conditions have resulted in developing improved cultivars that have high yields in favorable environments while producing reasonable and stable yields under stress.
Similar content being viewed by others
References
Allem, A.C. 2002. The origin and taxonomy of cassava. In: R.J. Hillocks, J.M. Thresh and A.C. Belloti (Eds.)Cassava: Biology, Production and Utilization, CABI Publishing, New York, pp. 1–16.
Alves, A.A.C. 2002. Cassava botany and physiology. In: R.J. Hillocks, J.M. Thresh and A.C. Bellotti (Eds.) Cassava: Biology, Production and Utilization. CABI Publishing, New York, pp. 67–89.
Angelov, M.N., Sun, J., Byrd, G.T., Brown, R.H. and Black, C.C. 1993. Novel characteristics of cassava, Manihot esculenta Crantz, a reputed C3-C4intermediate photosynthesis species. Photosynth. Res. 38: 61–72.
Aresta, R.B. and Fukai, S. 1984. Effects of solar radiation on growth of cassava (Manihot esculenta Crantz). II. Fibrous root length. Field Crops Res. 9: 361–371.
Berg, V.S., El-Sharkawy, M.A., Hernandez, A.D.P. and Cock, J.H. 1986. Leaf orientation and water relations in cassava. Annual Meeting of the American Society of Plant Physiologists, 8–12 June, Louisiana State University, Baton Rouge, LA, p. 186.
Calatayud, P.A., Barón, C.H., Velásquez, J.A., Arroyave, J.A. and Lamaze, T. 2002. Wild Manihot species do not possess C4photosynthesis. Ann. Bot. 89: 125–127.
Cayón, M.G., El-Sharkawy, M.A. and Cadavid, L.F. 1997. Leaf gas exchange of cassava as affected by quality of planting material and water stress. Photosynthetica 34: 409–418.
CIAT. 1979. Cassava Program Annual Report for 1978. Centro Internacional de Agricultura Tropical, Cali, Colombia.
CIAT. 1990. Cassava Program Annual Report for 1990. Centro Internacional de Agricultura Tropical, Cali, Colombia.
CIAT. 1993. Cassava Program Annual Report for 1993. Centro Internacional de Agricultura Tropical, Cali, Colombia.
CIAT. 1994. Cassava Program Annual Report for 1994. Centro Internacional de Agricultura Tropical, Cali, Colombia.
CIAT. 1995. Cassava Program Annual Report for 1995. Centro Internacional de Agricultura Tropical, Cali, Colombia.
Cock, J.H. 1984. Cassava. In: P.R. Goldsworthy and N.M. Fisher (Eds.) The Physiology of Tropical Field Crops, Wiley, New York, pp. 529–549.
Cock, J.H., Franklin, D., Sandoval, G. and Juri, P. 1979. The ideal cassava plant for maximum yield. Crop Sci. 19: 271–279.
Cock, J.H., Porto, M.C.M. and El-Sharkawy, M.A. 1985. Water use efficiency of cassava. III. Influence of air humidity and water stress on gas exchange of field grown cassava. Crop Sci. 25: 265–272.
Cock, J.H., Rianño, N.M., El-Sharkawy, M.A., Lopez, Y. and Bastidas, G. 1987. C3-C4intermediate photosynthetic characteristics of cassava (Manihot esculenta Crantz). II. Initial products of 14CO2 fixation. Photosynth. Res. 12: 237–241.
Connor, D.J. and Cock, J.H. 1981. Response of cassava to water shortage II. Canopy dynamics. Field Crops Res. 4: 285–296.
Connor, D.J., Cock, J.H. and Parra, G.E. 1981. Response of cassava to water shortage. I. Growth and yield. Field Crops Res. 4: 181–200.
De Tafur, S.M., El-Sharkawy, M.A. and Calle, F. 1997. Photosynthesis and yield performance of cassava in seasonally dry and semiarid environments. Photosynthetica 33: 229–257.
de Vries, C.A., Ferwerda, J.D. and Flach, M. 1967. Choice of food crop in relation to actual and potential production in the tropics. Neth. J. Agric. Sci. 19: 241–248.
Edwards, G.E., Sheta, E., Moore, B., Dai, Z., Fransceschi, V.R., Cheng, S.H., Lin, C.H. and Ku, M.S.B. 1990. Photosynthetic characteristics of cassava (Manihot esculenta Crantz), a C3 species with chlorenchymatous bundle sheath cells. Plant Cell Physiol. 31: 1199–1206.
El-Sharkawy, M.A. 1993. Drought-tolerant cassava for Africa, Asia, and Latin America: breeding projects work to stabilize productivity without increasing pressures on limited natural resources. Bioscience 43: 441–451.
El-Sharkawy, M.A. and Cadavid, L.F. 2002. Response of cassava to prolonged water stress imposed at different stages of growth. Exp. Agric. 38: 333–350.
El-Sharkawy, M.A. and Cock, J.H. 1984. Water use efficiency of cassava. I. Effects of air humidity and water stress on stomatal conductance and gas exchange. Crop Sci. 24: 297–502.
El-Sharkawy, M.A. and Cock, J.H. 1986. The humidity factor in stomatal control and its effects on crop productivity. In: R. Marcelle, H. Clijsters and M. Van Poucke (Eds.) Biological Control of Photosynthesis, Martinus Nijhoff Publishers, Dordrecht, Netherlands, pp. 187–198.
El-Sharkawy, M.A. and Cock, J.H. 1987a. Response of cassava to water stress. Plant Soil 100: 345–360.
El-Sharkawy, M.A. and Cock, J.H. 1987b. C3–C4 intermediate photosynthetic characteristics of cassava (Manihot esculenta Crantz). I. Gas exchange. Photosynth. Res. 12: 219–235.
El-Sharkawy, M.A. and Cock, J.H. 1990. Photosynthesis of cassava (Manihot esculenta). Exp. Agric. 26: 325–340.
El-Sharkawy, M.A., Cock, J.H. and De Cadena, G. 1984a. Stomatal characteristics among cassava cultivars and their relation to gas exchange. Exp. Agric. 20: 67–76.
El-Sharkawy, M.A., Cock, J.H. and De Cadena, G. 1984b. Influence of differences in leaf anatomy on net photosynthetic rates of some cultivars of cassava. Photosynth. Res. 5: 235–242.
El-Sharkawy, M.A., Cock, J.H. and Held, K.A.A. 1984c. Water use efficiency of cassava. II. Differing sensitivity of stomata to air humidity in cassava and other warm-climate species. Crop Sci. 24: 503–507.
El-Sharkawy, M.A., Cock, J.H. and Held, K.A.A. 1984d. Photosynthetic response of cassava cultivars (Manihot esculenta Crantz) from different habitats to temperature. Photosynth. Res. 5: 243–250.
El-Sharkawy, M.A., Cock, J.H. and Hernandez, A.D.P. 1985. Stomatal response to air humidity and its relation to stomatal density in a wide range of warm climate species. Photosynth. Res. 7: 137–149.
El-Sharkawy, M.A., Cock, J.H., Lynam, J.K., Hernandez, A.d.P. and Cadavid, L.F. 1990. Relationships between biomass, root-yield and single-leaf photosynthesis in field-grown cassava. Field Crops Res. 25: 183–201.
El-Sharkawy, M.A., De Tafur, S.M. and Cadavid, L.F. 1992a. Potential photosynthesis of cassava as affected by growth conditions. Crop Sci. 32: 1336–1342.
El-Sharkawy, M.A., Hernandez, A.D.P. and Hershey, C. 1992b. Yield stability of cassava during prolonged mid-season water stress. Exp. Agric. 28:165–174.
El-Sharkawy, M.A., De Tafur, S.M. and Cadavid, L.F. 1993. Photosynthesis of cassava and its relation to crop productivity. Photosynthetica 28: 431–438.
Essers, A.J.A. 1995. Removal of Cyanogens from Cassava Roots: Studies on Domestic Sun-drying and Solid-substrate Fermentation in Rural Africa. PhD thesis, Wageningen Agricultural University, Netherlands.
Fukai, S., Alcoy, A.B., Llamelo, A.B. and Patterson, R.D. 1984. Effects of solar radiation on growth of cassava (Manihot esculenta Crantz). I. Canopy development and dry matter growth. Field Crops Res. 9: 347–360.
Gibbons, A. 1990. New view of early Amazonia. Science 248: 1488–1490.
Hershey, C.H. and Jennings, D.L. 1992. Progress in breeding cassava for adaptation to stress. Plant Breed. Abstr. 62: 823–831.
Hibberd, J.M. and Quick, W.P. 2002. Characteristics of C4 photosynthesis in stems and petioles of C3flowering plants. Nature 415: 451–454.
Howeler, R.H. and Cadavid, L.F. 1983. Accumulation and distribution of dry matter and nutrients during a 12-month growth cycle of cassava. Field Crops Res. 7: 123–139.
Hozyo, Y., Megawati, M. and Wargiono, J. 1984. Plant production and potential productivity of cassava (Manihot esculenta Crantz). In: D. M. Tantera, Subandi, M. Ismunadji, S. Kusumo, J. Sujitno and Ph. Sutjipto (Eds.) Contributions of the Central Research Institute for Food Crops at Bogor, No 73, Central Research Institute for Food Crops, Bogor, Indonesia, pp. 1–20.
Iglesias, C., Hershey, C., Calle, F. and Bolaños, A. 1994. Propagating cassava (Manihot esculenta) by sexual seed. Exp. Agric. 30: 283–290.
Irikura, Y., Cock, J.H. and Kawano, K. 1979. The physiological basis of genotype- temperature interactions in cassava. Field Crops Res. 2: 227–239.
Kawano, K., Daza, P., Amaya, A., Rios, M. and Goncalves, W.M.F. 1978. Evaluation of cassava germplasm for productivity. Crop Sci. 18: 377–382.
Keating, B.A. 1981. Environmental Effects on Growth and Development of Cassava (Manihot esculenta Crantz) with Special Reference to Photoperiod and Temperature. PhD thesis, Department of Agriculture, University of Queensland, Australia.
Keating, B.A. and Evenson, J.B. 1979. Effect of soil temperature on sprouting and sprout elongation of stem cuttings of cassava. Field Crops Res. 2: 241–252.
Keating, B.A., Wilson, G.L. and Evenson, J.P. 1988. Effects of length, thickness, orientation, and planting density of cassava (Manihot esculenta Crantz) planting material on subsequent establishment, growth and yield. E. Afr. Agric. For. J. 53: 145–149.
Laetsch, W.M. 1974. The C4 syndrome: a structural analysis. Annu. Rev. Plant Physiol. 25: 27–52.
Lancaster, P.A. and Brooks, J.E. 1983. Cassava leaves as human food. Econ. Bot. 37: 331–348.
Leihner, D. 1983. Management and Evaluation of Intercropping Systems with Cassava. Centro Internacional de Agricultura Tropical, Cali, Colombia.
Molina, J.L. and El-Sharkawy, M.A. 1995. Increasing crop productivity in cassava by fertilizing production of planting material. Field Crops Res. 44: 151–157.
Oka, M., Limsila, J. and Sarakarn, S. 1987. Relationship between characteristics and germination ability of cuttings in cassava (Manihot esculenta Crantz). Jpn. Agric. Res. Q. 21: 70–75.
Paul, K. and Yeoh, H.H. 1987. K m values of ribulose-1,5-bisphosphate carboxylase of cassava cultivars. Phytochemistry 26: 1965–1967.
Pellet, D. and El-Sharkawy, M.A. 1993a. Cassava varietal response to phosphorus fertilization. I. Yield, biomass and gas exchange. Field Crops Res. 35: 1–11.
Pellet, D. and El-Sharkawy, M.A. 1993b. Cassava varietal response to phosphorus fertilization. II. Phosphorus uptake and use efficiency. Field Crops Res. 35: 13–20.
Pellet, D. and El-Sharkawy, M.A. 1997. Cassava varietal response to fertilization: growth dynamics and implications for cropping sustainability. Exp. Agric. 33: 353–365.
Porto, M.C.M. 1983. Physiological Mechanisms of Drought Tolerance in Cassava (Manihot esculenta Crantz). PhD thesis, University of Arizona, USA.
Ramanujam, T. 1990. Effect of moisture stress on photosynthesis and productivity of cassava. Photosynthetica 24: 217–224.
Ravindra, V. 1993. Cassava leaves as animal feed: potential and limitations. J. Sci. Food Agric. 61: 141–150.
Renvoize, B.S. 1972. The area of origin of Manihot esculenta. Econ. Bot. 26: 352–360.
Rogers, D.J. and Appan, S.G. 1973. Manihot and Manihotoides (Euphorbiacea), a computer-assisted study. Flora Newtropica, Monograph 13. Hafner Press, New York.
Tan, S.L. and Cock, J.H. 1979. Branching habit as a yield determinant in cassava. Field Crops Res. 2: 281–289.
Tscherning, K., Leihner, D.E., Hilger, T.H., Müller-Sämann and El-Sharkawy, M.A. 1995. Grass barriers in cassava hillside cultivation: rooting patterns and root growth dynamics. Field Crops Res. 43: 131–140.
Van Oirschot, Q.E.A., O’Brian, G.M., Dufour, D., El-Sharkawy, M.A. and Mesa, E. 2000. The effect of pre-harvest pruning of cassava upon root deterioration and quality characteristics. J. Sci. Food Agric. 80: 1866–1873.
Veltkamp, H.J. 1985. Physiological Causes of Yield Variation in Cassava (Manihot esculenta Crantz). PhD thesis, Agricultural University, Wageningen, Netherlands.
Ugent, D., Pozorski, S. and Pozorski, T. 1986. Archaeological manioc (Manihot) from coastal Peru. Econ. Bot. 40: 78–102.
Yeoh, H.H. and Chew, M.Y. 1976. Protein content and amino acid composition of cassava leaf. Phytochemistry 15: 1597–1599.
Yeoh, H.H. and Truong, V.D. 1996. Protein contents, amino acid compositions and nitrogen-to-protein conversion factors for cassava roots. J. Sci. Food Agric. 70: 51–54.
Yeoh, H.H., Badger, M.R. and Watson, L. 1980. Variation in K m (CO2) of ribulose-1,5- bisphosphate carboxylase among grasses. Plant Physiol. 66: 1110–1112.
Yeoh, H.H., Badger, M.R. and Watson, L. 1981. Variations in kinetic properties of ribulose-1,5-bisphosphate carboxylase among plants. Plant Physiol. 67: 1151–1155.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
El-Sharkawy, M.A. Cassava biology and physiology. Plant Mol Biol 56, 481–501 (2004). https://doi.org/10.1007/s11103-005-2270-7
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s11103-005-2270-7