ARS | Publication request: ASSESSING THE GENETIC DIVERSITY OF CITRUS BY UTILIZING MOLECULAR MARKERS

Submitted to: International Society of Citriculture Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 15, 2000
Publication Date: December 15, 2000
Citation: BARKLEY, N., ROOSE, M., KRUEGER, R. ASSESSING THE GENETIC DIVERSITY OF CITRUS BY UTILIZING MOLECULAR MARKERS. INTERNATIONAL SOCIETY OF CITRICULTURE ABSTRACTS. 2000.

Technical Abstract: The Citrus Variety Collection contains 900 accessions in the genus Citrus and related genera in the subfamily Aurantioideae. This collection has been built up over nearly 100 years and the amount of genetic diversity actually present is unclear. Evaluating genetic diversity will lead to designation of a core collection, which will represent the majority of the genetic diversity of the Variety Collection with minimal redundancy. The rationale for constructing a core collection is to simplify management of the collection, allow germplasm users to have easy access to the diversity present in citrus, reduce distribution costs, and to reduce the total number of accessions needed to develop testing procedures. Genetic diversity is being evaluated by utilizing simple sequence repeats (SSR). A total of twenty-four markers have been tested, of which sixteen have produced scorable bands. Approximately twenty polymorphic markers that are well distributed over the genome are needed to adequately determine the diversity of the CVC. After the core collection is constructed, chloroplast DNA (from within the core) will be evaluated for restriction site polymorphism by using universal primers that target specific sequences within the genome. This data will be used to determine which chloroplasts' genome is in most all accessions and aid in determining the maternal parent of accessions of unknown origin. Lastly, this project will include cloning a gene from each accession in the core to compare sequence divergence information. This project will help determine the level of genetic diversity, parentage of unknown accessions, and an evolutionary history of the various varieties.