Crop improvement can be defined as i. An art, a science, and technology of improving the genetic makeup of plants in relation to their economic use for the mankind. ii. The art and science of improving the heredity of plants for the benefit of mankind. iii. Science of changing and improving the heredity of plants 2. Genetics The study of heredity and the variation of inherited characteristics, the science of genetics enables plant breeders to predict to varying extents the outcome of genetic manipulation of plants. The techniques and methods employed in breeding are determined based on the genetics of the trait of interest, regarding, for example, the number of genes coding for it and gene action. For example, the size of the segregating population to generate in order to have a chance of observing that unique plant with the desired combination of genes depends on the number of genes involved in the expression of the desired trait.