In earlier days the extent of plant breeding as an art and as a science was much disputed. Plant breeding was practiced first when people learned to look for superior plants to harvest for seed; thus selection became the earliest method of plant breeding. The results of those primitive efforts in plant selection contributed much to the evolutionary development of each of the cultivated crops. The art of plant breeding lies in the ability of the breeder to observe differences that may have economic value in plants of the same species. Before breeders possessed the scientific knowledge that is available today, they relied largely on their skill and judgment in selecting the superior types. The breeders should be good observers, quick to recognize variations among plants of the same species, which could be used as the basis for establishing new varieties. Among the scientific disciplines essential to addressing this challenge, plant breeding will play a unique role by developing the new crops, ornamentals, or forest trees that meet societal needs. Plant breeders will develop plants that are adapted to our changing environment and that can improve environmental quality. The objective of this paper is to review the impact plant breeding in agriculture in general and in crop improvement, food security & investment specifically. The achievements of plant breeders are numerous, and can be grouped into several major areas of impact - yield increase, enhancement of compositional traits,crop adaptation, and the impact on crop production systems. Plant breeding is not without negative side effects, the replacement of local landraces with improved and varieties of narrow genetic base results in genetic vulnerability and genetic erosion. The limitation of genetic diversity directly impact on the lack of input materials for new breeding programs.