General considerations about polyploidy and differences between monoploids and diploids of maize
The concept of polyploidy has bean known for the past one hundred years, but scientists did not realize its full importance until the nineteen-thirties. Nowadays, polyploids can be artificially produced by the application of drugs and other methods. Therefore, polyploidy can be investigated on a scientific basis. These investigations have provided us not only with facts regarding genetics but also practical applications in plant breeding. Thus, some polyploids have proven to be superior to diploid plants in various respects, such as size of fruit or nutritional value. Investigations of polyploidy gave us the monoploid concept. This concept has not been of much value to plant breeders until Dr. Chase, now working at the DeKalb Agricultural Association, Inc., developed his new process of making inbred lines from monoploids of maize. At present, his method is still in an experimental stage but its results look promising and have attracted much attention. The writer of this paper had the privilege of working with Dr. Chase during the summer of 1955. He suggested the following investigation of polyploidy and the study of quantitative differences between monoploids and diploids of maize. The original plans included an experiment with, colchicine applications to diploids in order to create polyploids but this problem appeared to be too extensive and time-consuming. It was abandoned in favor of working directly with monoploids. The author feels very much indebted to Dr. Chase for providing the valuable but scarce monoploid plants for this study. She also gratefully acknowledges the help given her by Dr. Prior, Dr. Terwilliger, and Dr. Feyerherm from the Biology Department at Northern Illinois State College.