2011 Annual Report 1a.Objectives (from AD-416) To conduct cooperative research related to the evaluation, characterization, identification, and preservation of cultivated and indigenous plant genetic resources and to exchange plant germplasm that is of mutual interest. 1b.Approach (from AD-416) ARS and the Cooperator will exchange propagating material (true seed, budwood, hereinafter referred to as Breeding Material), of tropical and subtropical crops following recommended phytosanitary procedures, including quarantine. Breeding Material will be increased in the greenhouse or field for testing and evaluation for specific traits (e.g. disease resistance, enhanced yield and fruit quality) of interest or as commercial cultivars. DNA fingerprinting will be conducted to assess genetic diversity. GRIN training will be provided if deemed necessary by both parties. 3.Progress Report The objectives of the agreement correspond with objective 1 of the parent project: Evaluate tropical/subtropical fruit production systems and germplasm for broad agroenvironmental adaptation, high yield and productivity, and ability to produce fruits of superior quality. Budwood of 32 accessions of citrus was distributed to the Guanxi SubTropical Crops Research Institute from the USDA-ARS National Clonal Germplasm Repository for Fruit and Nut Crops at Riverside, California. Two molecular marker systems, SCoT (start codon targeted polymorphism) and ISSR (inter-simple sequence repeat) were used for identification and genetic comparison analysis of 23 mango germplasm accessions collected within the Guangxi province of China. Results indicated that the SCoT analysis better represents the actual relationships than ISSR analysis, although both analyses give similar results. The results also demonstrate that the SCoT marker system is useful for identification and genetic diversity analysis of mango cultivars. This is the first study employing SCoT marker to estimate the genetic diversity of Xiang Ya Mango type, and the first comparative analysis between SCoT and ISSR markers. This project was monitored through visits to laboratories and by communications with collaborators by phone and emails.