Title Page———– i
Certification———-ii
Dedication———– iii
List of Co-authoured Conference Papers on Maize Improvement —– iv
Acknowledgement——————–v
Table of Contents——————– viii
List of Tables—————- x
List of Figures——————–xiii
List of Appendices————— xiv
Abstract—————— xv
INTRODUCTION——— 1
LITERATURE REVIEW——- 4
Host plant resistance (HPR)——– 10
Screening and Selection of Promising Genotypes –10
Mating designs and combining abilities ——– 12
Heterosis or hybrid vigor ———–14
MATERIAL AND METHODS——– 15
Experiment 1: Field evaluation of local maize germplasm for resistance to stem borers in four environments—– 18
Cultural practices———20
Data collection————21
Statistical analysis———–23
Estimation of genetic variance components——— 23
Heritability estimates———24
Experiment 2: Diallel evaluation to obtain information on combining ability and heterosis of selected genotypes and generate reciprocal populations for further improvement. 26
Statistical analysis————- 27
Estimation of heterosis——28
RESULTS——– 29
Multivariate and cluster analyses: using data from artificially infested plots.— 34
Multivariate and cluster analyses: using data from naturally infested plot.——- 45
Multivariate and cluster analyses: using data from non-infested plots from Ibadan and Ikenne locations, combined53
The combining ability and heterotic effects for agronomic attributes and stem borer damage parameters in the 11 selected genotypes—- 61
DISCUSSION————- 85
SUMMARY AND CONCLUSION ———- 91
REFERENCES ———93
APPENDICES———-106