Diversity of avocado (Persea americana Mill.) cultivars from Antioquia (Northeast Colombia) and comparison with a worldwide germplasm collection

Authors: GLORIA PATRICIA CAÑAS-GUTIÉRREZ, LIBRADA ALCARAZ, JOSE IGNACIO HORMAZA, RAFAEL EDUARDO ARANGO- ISAZA, CLARA INÉS SALDAMANDO-BENJUMEA

Abstract: In this study, the genetic diversity of 90 avocado (Persea americana Mill) cultivars from Antioquia (Colombia) was compared to 67 germplasm collection accessions using 14 microsatellites. An average of 4.32 ± 2.0 alleles per locus was found, as observed in previous studies. The expected and observed heterozygosity ranges were 0.384-0.724 and 0.393-0.686, respectively. The Antioquian avocados were genetically structured according to an analysis of molecular variance test (fixation index (F_ST) = 0.054, P < 0.00001). An unweighted pair group method with arithmetic mean (UPGMA) dendrogram with F_ST paired data produced 2 clusters: one composed by Antioquian avocados and the other by the germplasm collection. Another UPGMA dendrogram with individual Nei-Li distances and additional STRUCTURE analysis separated the Antioquian avocados into 3 clusters (K = 3). Combining samples from the Colombian and germplasm collections produced K = 2. Genetic differentiations between the Antioquian and worldwide avocado germplasm collection could be due to crosses within the Antioquian avocados having been enhanced by insect pollinators, whereas avocados stored in the germplasm collection were constituted by cultivars with known genetic origins. Findings from this study demonstrated that criollo avocado genetics are unique in Antioquia, since the species has been naturally crossed in the field and its closest accession is from Guatemala. Nevertheless, it is important to continue genotyping this species in other locations in Colombia from Sylvester and cultivar populations of this crop to determine its origin.

Keywords: Germplasm, microsatellites, Persea americana, population structure, STRUCTURE

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