|Ray, D - UNIV OF ARIZONA|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 15, 2005
Publication Date: November 8, 2005
Citation: Coffelt, T.A., Ray, D.T. 2005. A new breeding method for guayule - an apomictic crop. Agronomy Abstracts. CD-Rom (P6793) Technical Abstract: Guayule (Parthenium argentatum Gray) is a perennial shrub native to the Chihuahuan Desert. Apomictic reproduction in guayule makes breeding progress difficult. New breeding methods to take advantage of the facultative apomixis or occasional sexual reproduction that occurs in guayule are needed for faster breeding progress. The objective of this study is to evaluate the possibility of utilizing the pedigreed natural crossing method as a breeding method in guayule. Plants that reproduce by apomixis and those that are highly self-pollinated both have highly uniform progenies, except for the occasional off-type. This off-type is frequently the result of out-crossing in self-pollinated species as well as in facultative apomictic species. Inter-planting of parents, allowing crossing to occur naturally, harvesting seed from the parents, and then examining the progeny for off-types can be used to develop populations for further selection and development of desirable lines. In self-pollinated species the development of uniform lines may take several generations of selection and self pollination, while in an apomictic species uniform lines may be able to be developed within one generation of apomictic reproduction. The added advantage is that any hybrid vigor associated with the original cross would also be fixed. Preliminary studies indicate that utilizing the pedigreed natural crossing method or modifications of this method in guayule is feasible.