ABSTRACT

Twenty hybrid maize genotypes were evaluated in Umuahia   Abia state, to study their yield, yield components and proximate composition. The genotypes were separated into two (yellow and white genotypes) and each group laid out as a separate experiment for two years from June- November 2014 and 2015. In each experiment, the genotypes were laid out in a randomized complete block design replicated three times.  Genotypes did not show significant differences (p> 0.05) among themselves for all Agronomic attributes in both experiments; however, genotypes exhibited significant variability (p< 0.001) for most yield traits and for insects, disease and rodents score parameters. There was significant genotype x environment interactions for most traits. Broadsense heritability and genetic advance for number of plants harvested/plot, shelled grain weight, ear height, ear aspect, rust, ear rot, blight and stalk lodging were high for white maize genotypes evaluated in 2015, but only streak was high in 2014; likewise, for the yellow maize, only cob length was high in 2014, while others, including those in 2015 were low. Correlation for days to tasselling, ear aspect traits, plant aspect, stem borer, insect damage, blight, rodents damage and ear rot were high and significant in the white and the yellow maize genotypes. For proximate composition, crude fat, moisture content and dry matter had high heritability for white maize in 2015, low in all traits of both 2014 white maize genotypes and those of yellow maize genotypes in 2014 and 2015. There was no correlation of any of the proximate components with seed yield. Results also showed that the range of proximate composition obtained for both white and yellow genotypes were: crude protein 9.54-11.18 for yellow, 10.70-1.78 for white, crude fat 2.15-5 for yellow, 4.76-5.05 for white, moisture content 12.3014.33 for yellow, 10.64-16.45 for white, Ash 0.97-1.46 for yellow, 1.16-2.29 for white, crude fibre 1.36-1.75 for yellow, 1.75-1.97 for white, carbohydrate 68.35- 70.89 for yellow, 67.92-70.77 for white  and dry matter 85.68-87.70 for yellow, 86.69-89.42 for white. Generally, yield was higher in 2014 than 2015, the yields obtained from both experiments showed that the hybrids far exceeded those of their local checks, that is oba 98 and Oba supper2. From the result, some outstanding genotypes were selected for performance in yield. For the white maize genotypes, we had, DKC 21-47 with field weight 2.8t/ha, shelled grain weight 2.5t/ha and seed weight of 2t/ha. For the yellow maize genotypes, we had DKC91-44 with field weight 5t/ha, shelled grain weight 4,t/ha and seed weight of 2.3t/ha.  Yields from the yellow maize far exceeded those obtained from white maize. The Yellow maize genotypes were more tolerant to insect pest, disease and animal damage than the white.  Result suggested that the test population may have been bred from identical parents. It was concluded that further improvement of the white genotypes be made by incorporating factors that will increase tolerance/ control to traits like ear rot, streak, blight and rodents damage to make it suitable for the Umudike/ S/E ecological zone.