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| John Preece Dr. John Preece became the Supervisory Research Leader of the USDA-ARS National Clonal Germplasm Repository Davis, CA and the National Arid Land Plant Genetic Resource Unit, Parlier, CA in January 2010 and the Acting Research Leader for the National Clonal Germplasm Repository for Citrus and Dates in Riverside, CA. Prior to assuming this new position, Dr. Preece was a horticulture professor at Southern Illinois University Carbondale for nearly 30 years. His teaching duties included General Horticulture, Plant Propagation, and Plant Growth and Development. Since joining the USDA, the focus of Dr. Preece’s research has been on Mediterranean fruit and nut crops in the collection at the Davis genebank. Currently and over the years, much of the focus of the research has been on Dr. Preece’s research has focused on clonal propagation of woody plants. This includes rooting of cuttings and micropropagation (plant tissue culture). He has been interested in plant hormones and the roles of juvenility and phase change to adult have on propagation success. This research elucidated methods to obtain propagation material from the juvenile portions of mature plants has been shown to improve propagation success. “Propagation Of Difficult To Propagate Fruit Trees” Fruit crops are generally not propagated by seeds because the seedlings do not come true and produce the same quality fruit as the parent. Therefore, the highest quality fruit crops are propagated by rooting cuttings, layering, micropropagation, and grafting and budding. These methods of vegetative or clonal propagation have been used by humans for thousands of years (except for micropropagation, a more recent development). Understanding the regeneration processes that are necessary for propagation and how they can be manipulated both simplifies and greatly increases the chances of success. The processes of root initiation and development in cuttings is explained and shown how to be used in practical plant propagation. Layering is rooting the cuttings before removal from the parent plant and this is explained. The processes in micropropagation and principles of grafting and budding are also shown in an understandable manner. Many tips and pointers are given that will help improve your propagation success. All plants begin with the propagator. |