Conversion Of Okomasa-A Normal Open Pollinated Maize Variety to Quality Protein Maize Using the Backcross Breeding Approach.

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Biofortification of cereals especially maize which is the major cereal consumed in Ghana will help increase the health status of Ghanaians. A study was conducted with the main objective of enhancing the nutritional qualities of Okomasa, a normal high yielding open-pollinated variety by introgressing the opaque-2 gene, which confers high lysine and tryptophan into the said variety. The study was conducted at the breeding nurseries of the Maize Improvement Programme at the CSIR-Crops Research Institute at Fumesua which is located on Lat 6o 451N and Long 1o 361W from 2007 minor season to 2009 minor seaon. Obatanpa, a quality protein maize variety was used as the gene source to improve the nutritional status of Okomasa. The F1 was advanced to the F2 by self pollinating good F1 plants. Kernels from each cob were screened under the light box. Three levels of kernel modification were observed, less than 25% opaque, between 25%-50% opaque and completely opaque or over 50% opaque. The Chi-square test was employed to test the goodness of fit of the observed ratios to the expected genetic ratios in the F2 segregating material. The frequency of completely opaque (homozygote dominant) and heterozygotes were lower than the homozygote recessives. Additive genetic variance for plant height, ear height, cob length, cob diameter and rows per cob recorded low values of 8.76, 8.87, 0.13, 0.0, and 0.10 respectively. 95% of the phenotype was attributed to genetic variance, and 5% attributed to genetic variance which implies genetic gain will be maximized. Broad sense heritability values for plant height, ear height, and cob length were high: 0.95, 0.81 and 0.75. Narrow sense heritability values were low for the same traits which is an indication that environmental factors influenced maize production in this particular study. Correlation among parameters studied showed positive values in the two parents with plant height and ear height in both parents being significant. The F1 generation also showed significant values between plant and ear height.
A Thesis Submitted to the Department of Crop and Soil Sciences of the Faculty of Agriculture, Kwame Nkrumah University of Science and Technology, Kumasi in Partial Fulfilment of the Requirement for the Award of a Master of Science Degree in Agronomy (Plant Breeding), 2010.