Location: Sustainable Perennial Crops LaboratoryTitle: Genetic characterization of guava (psidium guajava l.) Germplasm in the United States using microsatellite markers Author
Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/7/2014
Publication Date: 1/22/2014
Citation: Sitther, V., Zhang, D., Harris, D., Zee, F.T., Yadav, A., Meinhardt, L.W., Dhekney, S. 2014. Genetic characterization of guava (psidium guajava l.) Germplasm in the United States using microsatellite markers. Genetic Resources and Crop Evolution. DOI: 10.1007/s10722-014-0078-5. Interpretive Summary: Guava is an important fruit crop in tropical regions of the United States, where it is cultivated for fresh fruit, jam, jelly, and juice production. A guava germplasm collection has been maintained at the USDA-ARS Tropical Plant Genetic Resources and Disease Research Station, in Hilo, Hawaii. Information on genetic diversity in the guava collection is essential for efficient conservation and use of guava germplasm in production and breeding. An experiment was carried out to analyze genetic diversity in this guava collection using DNA fingerprinting technology. Results from the study showed that the collection consists of guava trees with a diverse genetic background that represents the geographic origins of guava. The result also revealed genetic redundancy and gaps of genetic diversity in this collection. The resultant information provides new insight into the diversity of the guava germplasm, which will be valuable in future breeding endeavors and the conservation of guava genetic resources. These results will be used by plant breeders, germplasm curators and ultimately the guava growers.
Technical Abstract: Genetic diversity of thirty five Psidium guajava accessions maintained at the USDA, National Plants Germplasm System, Hilo, HI, was characterized using 20 simple sequence repeat (SSR) markers. Diversity analysis detected a total of 178 alleles ranging from four to 16. The observed mean heterozygosity (0.16) and inbreeding coefficient (0.78) indicated a high level of inbreeding among the accessions tested. Multi-locus DNA fingerprints based on the 20 SSR loci unambiguously differentiated all the accessions and revealed the absence of duplicated samples. Results of ordination and cluster analysis suggested that the genetic relationships between majorities of the accessions could be explained by geographic origins, mainly including tropical America, Southeast Asia and Hawaii. Bayesian cluster analysis partitioned the accessions into groups that were largely compatible with the result of ordination and cluster analysis. Accessions from Southeast Asia were dominantly white fleshed, whereas accessions from tropical America and Hawaii were of diverse flesh colors. The results indicate that accessions from the same region are likely derived from a small number of common ancestors or progenitors. All 20 SSRs were transferable to the wild species including P. guineense, P. sartorianum, and P. friedrichsthalianum. Application of SSR markers in the USDA/ARS germplasm collection provides new insight into the diversity of the guava germplasm, which will be valuable in future breeding endeavors and the conservation of guava genetic resources.