Crop improvements have been one of the most important human endeavors in history, for a very good reason - survival. Initially such improvements were achieved by repeated selections for quantity and quality of food as guided by experience only. Further advancement was made by our forefathers who recognized that both animals and plants could be selected and crossed to reproduce and upgrade species. The knowledge of genetics guided the development of the breeding program from its infancy to maturity, eventually leading it into the era of the green revolution and gene revolution. The inital breeding program was based on the principles of genetics. By classical manipulation of chromosomes, many new varieties or species of important crops were created through hybridization, pure line selections and mutations. The contribution of the breeding techniques reached their peak in improving crop productivity in the 1960's. The achievements were so dramatic, it is referred to as the green revolution. These operations have limitations such as sexual incompatibility. To overcome these limitations the tissue culture techniques were developed in the 1950's. This led to the development of protoplast fusion in the 1970's. The contributions made by these new technologies have been enormous and more importantly they paved the way for the current advancement of biotechnology. The application of biotechnology to crop improvement ushers us into a new era of the gene revolution.