Cassava ( Manihot esculenta Cranzt) is an important food security crop for poor rural communities particularly in Africa. However, little is known about variability of critical root nutritional and quality traits of African cassava germplasm. Cassava roots contain low levels of important micronutrients and its quality can be influenced by the levels of cyanogenic glucosides. Roots from fourteen accessions comprising Kenyan local landraces and improved clones were screened for their nutritional traits including the contents of cyanogenic glycosides, protein and the micro nutrients iron and zinc. Trait stability and the effects of the environment on the expression of the nutritional traits were evaluated using various genotype (G) by environment (E) interaction study models. There were significant (p ≤ 0.05) differences for all the nutritional traits in the three test sites of Baringo, Kericho and Nakuru in Kenya. Contents of cyanogenic glycosides in both roots and leaves, total root proteins, root iron and zinc ranged from 31.8 ppm to 90.8 ppm; 20.8 ppm to 154.4 ppm; 1.15% to 3.47%; 17.81 ppm to 59.69 ppm and 39.39 ppm to 118 ppm, respectively. The sites were also significantly (p ≤ 0.05) different from each other with the highest cyanogenic content in leaves and roots expressed at the Nakuru site. Regression analysis was used to assess genotype response to environments. Regression coefficients (b i ) obtained ranged from 0.13 to 2.23 for all traits combined indicating wide variability in quality trait among the test germplasm. Analysis for sensitivity to environmental change SE i 2 revealed that cassava genotypes differed in their level of sensitivity. The root cyanide trait had the highest mean SE i 2 which indicated that it was the least stable quality trait in the cassava germplasm. This implies that the same cassava genotypes will give food of different quality depending on growing environment. The observed values for protein and mineral contents suggest the potential for improving the nutritive value of local cassava germplasm.
C. A. Allen, “The Origin of Manihot esculenta Crantz (Euphorbiaceae),” Crop Evolution, Vol. 41, No. 3, 1994, pp. 133-150. doi:10.1007/BF00051630
K. M. Olsen and B. A. Schaal, “Microsatellite Variation in Cassava (Manihot esculenta, Euphorbiaceae) and Its Wild Relatives: Further Evidence for a Southern Amazonian Origin of Domestication,” American Journal of Botany, Vol. 88, No. 1, 2001, pp. 131-142. doi:10.2307/2657133
J. Cock, “Cassava. New Potential for a Neglected Crop,” Westview Press, Boulder, 1985.
K. Kawano, K. Narintaraporn, P. Narintaraporn, S. Sarakarn, A. Limsila and W. Watananonta, “Yield Improvement in a Multistage Breeding Program for Cassava,” Crop Science, Vol. 38, No. 2, 1998, pp. 325-332. doi:10.2135/cropsci1998.0011183X003800020007x
C. Iglesias, J. Mayer, A. L. Ch′avez and F. Calle, “Genetic Potential and Stability of Carotene Content in Cassava Roots,” Euphytica, Vol. 94, No. 3, 1997, pp. 367-373. doi:10.1023/A:1002962108315
M. A. El-Sharkawy, “Drought-Tolerant Cassava for Africa, Asia and Latin America,” Biological Science, Vol. 43, 1993, pp. 441-451.
P. Kakes, “Properties and Functions of the Cyanogenic System in Higher Plants,” Euphytica, Vol. 48, No. 1, 1990, pp. 25-43.
J. M. Mc Mahon, W. L. B. White and R. T. Sayre, “Cyanogenesis in Cassava (Manihot esculenta Crantz),” Journal of Experimental Botany, Vol. 46, No. 288, 1995, pp. 731-741.
P. Lundquist, “Determination of Cyanide and Thiocyanate in Humans,” Linkoping University, Linkoping, 1992, p. 142.
B. Ballantyne, “Acute Systemic Toxicity of Cyanides by Topical Application to the Eye,” Journal of Toxicology, Vol. 2, No. 2-3, 1983, pp. 119-129.
J. L. Way, “Cyanide Intoxication and Its Mechanism of Antagonism,” Annual Review of Pharmacology and Toxicology, Vol. 24, 1984, pp. 451-481. doi:10.1146/annurev.pa.24.040184.002315
R. P. Johnson and J. W. Mellors, “Arteriolization of Venous Blood Gases: A Clue to the Diagnosis of Cyanide Poisoning,” Journal of Emergency Medicine, Vol. 6, No. 5, 1988, pp. 401-404. doi:10.1016/0736-4679(88)90014-5
M. Ernesto, A. P. Cardoso, D. Nicala, E. Mirione, F. Massaza, J. Cliff, M. R. Haque and J. H. Bradbury, “Persistent Konzo and Cyanogens Toxicity from Cassava in Northern Mozambique,” Acta Tropica, Vol. 82, No. 3, 2002, pp. 357-362. doi:10.1016/S0001-706X(02)00042-6
G. Padjmaja, “Cyanide Detoxification in Cassava for Food and Feed Use,” Critical Reviews in Food Sciences and Nutrition, Vol. 35, 1995, pp. 259-339.
H. Rosling, “Cassava Toxicity and Food Security,” Report for UNICEF African Household Food Security Programme, 1988, p. 40.
M. R. Grace, “Elaboracion de la Yuca,” Coleccion FAO: Organization de las, 1977.
TRIP, “Cassava Breeding, Cytogenetics and Histology. Germplasm Enhancement, Root and Tuber Crops Improvement Program,” Archival Report (1989-1993), IITA, Ibadan, 1993, p. 89.
G. H. Bruijn, “Etude de caractere cyanogenetique du manioc (Manihot esculenta Crantz),” Mededelingen Land Bouwhoge School, Wagenigen, Vol. 71, 1971, p. 140.
J. B. Mason and M. Garcia, “Micronutrient Deficiency— the Global Situation,” SCN News, Vol. 9, 1993, pp. 11-16.
R. M. Welch, G. F. Combs Jr. and J. M. Duxbury, “Toward a ‘Greener’ Revolution,” Issues in Science and Technology, Vol. 14, 1997, pp. 50-58.
WHO, “Malnutrition Worldwide,” Geneva, 1999, pp. 1-13. http://www.who.int/nut/malnutrition_ worldwide.htm.
B. Caballero, “Global Patterns of Child Health: The Role of Nutrition,” Annuals of Nutrition and Metabolism, Vol. 46, No. 1, 2002, pp. 3-7. doi:10.1159/000066400
WHO, “Reducing Risks, Promoting Healthy Life,” The World Health Report, World Health Organization, Geneva, 2002, pp. 1-168.
A. J. A. Buitrago, “La yuca en la alimentaci′on animal,” Centro Internacional de Agricultura Tropical (CIAT), Cali, 1990, p. 446.
L. Babu and S. R. Chatterjee, “Protein Content and Amino Acid Composition of Cassava Tubers and Leaves,” Journal of Root Crops, Vol. 25, No. 20, 1999, pp. 163-168.
C. H. Hendershot, “A Literature Review and Research Recommendations on Cassava (Manihot esculenta Crantz),” University of Georgia, Athens, 1972.
H. E. Bouis, “Enrichment of Food Staples through Plant Breeding: A New Strategy for Fighting Micronutrient Malnutrition,” Nutrition, Vol. 16, No. 7, 2000, pp. 701-704. doi:10.1016/S0899-9007(00)00266-5
G. F. Combs Jr., R. M. Welch, J. M. Duxbury, N. T. Uphoff and M. C. Nesheim, “Food-Based Approaches to Preventing Micronutrient Malnutrition: An International Research Agenda,” Cornell University, Ithaca, 1996, pp. 1-68.
R. M. Welch and R. D. Graham, “A New Paradigm for World Agriculture: Meeting Human Needs,” Field Crops Research, Vol. 60, No. 1-2, 1999, pp. 1-10. doi:10.1016/S0378-4290(98)00129-4
G. Subbulakshmi and M. Naik, “Food Fortification in Developing Countries—Current Status and Strategies,” Journal of Food Science and Technology, Vol. 36, 1999, pp. 371-395.
R. Yip, “The Challenge of Improving Iron Nutrition: Limitations and Potentials of Major Intervention Approaches,” European Journal of Clinical Nutrition, Vol. 51, No. 5, 1997, pp. S16-S24.
C. S. Lin and L. P. Lefkovitch, “Stability Analysis: Where Do We Stand?” Crop Science, Vol. 26, No. 5, 1986, pp. 894-900.
Finlay and Wilkinson, “The Analysis of Adaptation in Plant-Breeding Programme,” Australian Journal of Agriculture Research, Vol. 14, No. 6, 1963, pp. 742-754.
Eberhart and Russell, “Stability Parameters for Comparing Varieties,” Crop Science, Vol. 6, 1966, pp. 36-40.
G. H. Freeman, “Statistical Methods for the Analysis of Genotype-Environment Interactions,” Heredity, Vol. 31, 1973, pp. 339-354.
M. Chakroun, C. M. Tliaferro and R. W. McNew, “Genotype-Environment Interactions for Bermuda Forage Yields,” Crop Science, Vol. 30, 1990, pp. 49-53. doi:10.2135/cropsci1990.0011183X003000010011x
F. N. Wachira, W. Ng’etich, J. Omolo and G. Mamati, “Genotype-Environment Interactions for Tea Yields,” Euphytica, Vol. 127, No. 2, 2002, pp. 289-296. doi:10.1023/A:1020273616349
M. D. Casler and A. W. Hovin, “Genotyp-Environment Interaction for Reed Canary Grass Forage Yield,” Crop Science, Vol. 24, 1984, pp. 633-636. doi:10.2135/cropsci1984.0011183X002400040002x
NARAPR, “The Picrate Test in Cassava: A Rapid Assay for Cyanogenic Potential Manual, National Roots and Tuber Crops Programme,” Namulonge Agricultural Research and Animal Production Research Institute, Kampala, 2004.
“Approved Methods of the American Association of Cereal Chemists (AACC),” Method, Vol. 2, 1983, pp. 44-13.
J. R. Okalebo, K. W. Gathua and P. L. Woomer, “Laboratory Methods of Soil and Plant Analysis,” Working Manual, Second Edition, 2002.
SAS Institute, Inc. JMP. Version 3.1. Cary, North 1995， Carolina.
A. L. Chavez, T. Sanchenz and H. Caballos, “Variation in Quality Traits in Cassava Roots Evaluated in Land Races and Improved Clones,” Euphytica, Vol. 143, 2005, pp. 125-133. doi:10.1007/s10681-005-3057-2
A. G. O. Dixon, G. N. Ssemakula and J. Mkumbira, “Genetic Enhancement of Beta-Carotene, Iron and Zinc Contents in Cassava for Alleviating Micronutrient Deficiency,” Proceedings of the African Crop Science Conference, 2005, pp. 169-173.
J. O. Lorenzo, M. T. B. Ramos and T. L. Valle, “Cyanide Contents in Cassava Cultivars Used for Consumption in the State of Sao Paulo,” Braganita, Vol. 52, 1993, pp. 1-5.