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United States Department of Agriculture

Agricultural Research Service

Research Project: CONSERVATION AND UTILIZATION OF SUBTROPICAL/TROPICAL FRUIT CROPS, SUGARCANE, AND TRIPSACUM GENETIC RESOURCES Title: Molecular Characterization and Genetic Structure in Avocado (Persea americana Mill.) Using Simple Sequence Repeat (SSR) Markers

Authors
item Boza, Edward
item Tondo, Cecile
item Kuhn, David
item Meerow, Alan
item Moore, John
item Campbell, Richard -
item Ledesma, Noris -
item Gutierrez, Osman
item Schnell, Raymond -

Submitted to: Annual International Plant & Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: November 10, 2011
Publication Date: January 16, 2012
Citation: Boza, E.J., Tondo, C.L., Kuhn, D.N., Meerow, A.W., Moore, J.M., Campbell, R.J., Ledesma, N., Gutierrez, O.A., Schnell, R.J. 2012. Molecular Characterization and Genetic Structure in Avocado (Persea americana Mill.) Using Simple Sequence Repeat (SSR) Markers. Annual International Plant & Animal Genome Conference. Annual International Plant & Animal Genome Conference, January 14-18, 2012, San Diego, CA.

Interpretive Summary: Avocado (Persea americana Mill.) is an economically important tropical fruit native to Mesoamerica. It belongs to the Lauraceae family and is subdivided in three horticultural races (Guatemalan, Mexican, and West Indian) based primarily on ecological adaptation, botanical and physiological traits. The objectives of this study are: a) to characterize the population structure, genetic diversity, and horticultural race of 344 total plants in the SHRS, Fairchild Farm, and P. schideana collections using a set of 20 SSR markers and b) to evaluate the mislabeling errors present in the collection. Preliminary fingerprinting analysis using a set of 20 SSR markers amplified a total of 331 alleles with a mean number of alleles per locus of 16.55 and average polymorphism information content (PIC) value of 0.75 indicating a high variability in the allele frequency for the collection. Bayesian analysis clustered the individuals into five groups representing the Guatemalan, Mexican, West Indian races of P. americana , admixed interracial hybrids and a P. schideana species group. In addition, Principal Component Analysis (PCA) and genetic distance analysis were calculated among all possible individual combinations within the SSR diversity data with results agreeing well with the Bayesian analysis. Although the 20 SSRs do not provide complete resolution of all individuals, we were able to estimate mislabeling errors at approximately 9%.

Technical Abstract: Avocado (Persea americana Mill.) is an economically important tropical fruit native to Mesoamerica. It belongs to the Lauraceae family and is subdivided in three horticultural races (Guatemalan, Mexican, and West Indian) based primarily on ecological adaptation, botanical and physiological traits. The objectives of this study are: a) to characterize the population structure, genetic diversity, and horticultural race of 344 total plants in the SHRS, Fairchild Farm, and P. schideana collections using a set of 20 SSR markers and b) to evaluate the mislabeling errors present in the collection. Preliminary fingerprinting analysis using a set of 20 SSR markers amplified a total of 331 alleles with a mean number of alleles per locus of 16.55 and average polymorphism information content (PIC) value of 0.75 indicating a high variability in the allele frequency for the collection. Bayesian analysis clustered the individuals into five groups representing the Guatemalan, Mexican, West Indian races of P. americana , admixed interracial hybrids and a P. schideana species group. In addition, Principal Component Analysis (PCA) and genetic distance analysis were calculated among all possible individual combinations within the SSR diversity data with results agreeing well with the Bayesian analysis. Although the 20 SSRs do not provide complete resolution of all individuals, we were able to estimate mislabeling errors at approximately 9%.

Last Modified: 10/20/2014
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