Agricultural research is key in developing new hybrids which adapt well to the effect of climate change. It helps in improving food security in many nations around the globe because of developing new hybrids resistant to pests, diseases, and tolerant to drought. This book focuses on evaluation of tropical maize hybrids across locations to identify disease resistant, stable and high yielding genotypes. This book also focuses on developing new maize hybrids using combining ability studies using the line by tester mating design.