Decrease in Lysine and Tryptophan Content in S2 Inbred Lines from a Quality Protein Maize (QPM) Variety in a Breeding Program


Several countries in Africa, Latin America along with China have incorporated QPM in their Agricultural development plan. A new quality protein maize variety (QPM) was developed by breeders and farmers using the participatory breeding approach in the DR-Congo. It is adapted to all the maize growing regions in the country. Inbred lines from this new variety were produced for further development of maize synthetic populations. The main objective of the present study is to determine the level of amino acid changes in early generations of inbred lines. The results of the study revealed a significant decrease of 33% and 38% of tryptophan in S1 and S2 inbred lines compared to the original parental MUDISHI 3 population, respectively. There was a decrease of 15% of lysine in S2 inbred lines compared to the parental MUDISHI 3. Actually, S2 inbred lines of MUDISHI 3 contain similar level of lysine compared to the genetically improved normal maize (Salongo 2) that is currently released. The development of composite lines is recommended over synthetic populations to maintain the high levels of lysine and tryptophan along with other desirable agronomic characteristics since they involve the intercrossing of open pollinated varieties.

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Nkongolo, K. and Mbuya, K. (2015) Decrease in Lysine and Tryptophan Content in S2 Inbred Lines from a Quality Protein Maize (QPM) Variety in a Breeding Program. American Journal of Plant Sciences, 6, 181-188. doi: 10.4236/ajps.2015.61021.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Mbuya, K., Nkongolo, K.K., Kalonji-Mbuyi, A. and Kizungu, R. (2010) Participatory, Selection and Characterization of Quality Protein Maize (QPM) Varieties in Savana Agro Ecological Region of DR-Congo. Journal of Plant Breeding Crop Sciences, 2, 325-332.
[2] Narro, L.A., Duran, J.F., George, M.L.C., Arcos, A.L., Osorio, V. and Warburton, M.L. (2012) Comparison of the Performance of Synthetic Maize Varieties Created Based on Either Genetic Distance or General Combining Ability of the Parents. Maydica, 57, 83-91.
[3] Hallauer, A.R. and Miranada, J.B.F. (1988) Quantitative Genetics of Maize. Iowa State University Press, Ames.
[4] Mbuya, K., Nkongolo, K.K., Narendrula, R., Kalonji-Mbuyi, A. and Kizungu, R.V. (2012) Development of Quality Protein Maize (QPM) Inbred Lines and Genetic Diversity Assessed with ISSR Markers in Maize Breeding Program. American Journal of Experimental Agriculture, 2, 626-640.
[5] Derera, J., Pixley, V. and Giga, D.P. (2001) Resistance of Maize to the Maize Weevil. I. Antibiosis. African Crop Science Journal, 9, 431-440.
[6] Dhliwayo, T., Pixley, K. and Kazemebe, V. (2005) Combining Ability for Resistance to Maize Weevil among 14 Southern African Maize Inbred Lines. Crop Sciences, 45, 662-667.
[7] Mwololo, J.K., Okori, P., Mugo, S., Tefera, T., Yoseph, B., Otim, M. and Munyiri, S.W. (2012) Phenotypic and Genotypic Variation in Tropical Maize Inbred Lines for Resistance to the Maize Weevil and Larger Grain Borer. International Journal of Agricultural Sciences and Research, 2, 41-52.
[8] Lou, X.Y., Zhu, J., Zhang, Q.D., Zang, R.C., Chen, Y.B., Yu, Z.L. and Zhao, Y.J. (2005) Genetic Control of the Opaque-2 Gene and Background Polygenes over Some Kernel Traits in Maize (Zea mays L.). Genetica, 124, 291-300.
[9] Krivanek, A.F., De Groote, H., Gunaratna, N.S., Diallo, A. and Friesen, D. (2007) Breeding and Disseminating Quality Protein Maize (QPM) for Africa. African Journal of Biotechnology, 6, 312-324.
[10] AOAC (2006) Official Methods of Analysis. 18th Edition, Association of Official Analytical Chemists, Gaithersburgs, MD.
[11] Bhatia, C.R. and Rabson, R. (1987) Relationship of Grain Yield and Nutritional Quality. In: Olson, R.A. and Frey, K.J., Eds., Nutritional Quality of Cereal Grains: Genetic and Agronomic Improvement (Agronomy Monograph, 28), ASA, CSSA, and SSSA, Madison, 11-43.
[12] Pixley, K.V. and Bjarnason, M. (2002) Stability of Grain Yield, Endosperm Modification and Protein Quality of Hybrid and Open-Pollinated Quality Protein Maize (QPM) Cultivars. Crop Sciences, 42, 1882-1890.
[13] Lima, M.D.A., de Souza, C.L., Bento, D.A.V., de Souza, A.P. and Carlini-Garcia, L.A. (2006) Mapping QTL for Grain Yield and Plant Traits in Tropical Maize Population. Molecular Breeding, 17, 227-239.
[14] Agrama, H.A., Moussa, M.E., Naser, M.E., Tarek, M.A. and Ibrahim, A.H. (1999) Mapping of QTL for Downy Mildew Resistance in Maize. Theoretical and Applied Genetics, 99, 519-523.
[15] Ming, R., Brewbaker, J.L., Pratt, R.C., Musket, T.A. and McMullen, M.D. (1997) Molecular Mapping of a Major Gene Conferring Resistance to Maize Mosaic Virus. Theoretical and Applied Genetics, 95, 271-275.
[16] Babu, K.B., Agrawal, P.K., Saha, S. and Gupta, H.S. (2014) Mapping QTLs for Opaque-2 Modifiers Influencing the Tryptophan Content in Quality Protein Maize Using Genomic and Candidate Gene-Based SSRs of Lysine and Tryptophan Metabolic Pathway. Plant Cell Report, 34, 37-45.
[17] Vasal, S.K., Villegas, E., Bjarnason, M., Gelaw, B. and Goertz, P. (1980) Genetic Modifiers and Breeding Strategies in Developing Hard Endosperm Opaque-2 Materials. In: Pollmer, W.G. and Phipps, R.H., Eds., Improvement of Quality Traits of Maize for Grain and Silage Use, Martinus Nijhoff, London, 37-73.
[18] Greetha, K.B., Lending, C.R., Lopes, M.A., Wallace, J.C. and Larkins, B.A. (1991) Opaque-2 Modifiers Increase γ-Zein Synthesis and Alter Its Spatial Distribution in Maize Endosperm. Plant Cell, 3, 1207-1219.
[19] Pandey, S., Vasal, S.K., De Leon, C., Ortega, A., Granados, G. and Villegas, E. (1984) Development and Improvement of Maize Populations. Genetika, 16, 23-42.

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