Genetic structure and diversity of Annona squamosa in Mayan homegardens of Yucatán Peninsula

Abstract

Many plant and animal species have been domesticated in southeastern Mexican homegardens, resulting in changes in their genetic variability. One of the most representative fruit trees in these systems is Annona squamosa L. We wanted to know if the predominant type of economic activity in a given area affects the distribution of genetic variability in A. squamosa. In order to answer this question, we analyzed 14 populations in 5 different socioeconomic regions in the states of Yucatán and Quintana Roo, using isozyme analysis. All the enzyme markers were polymorphic with 3 or 4 alleles. The mean number of alleles and alleles in polymorphic loci were high than other cultivated trees, suggesting no effect of genetic drift. The mean observed heterozygosity was 0.373 ± 0.03, while the expected heterozygosis was 0.470 ± 0.023. The results from the hierarchical analysis indicated that the greatest variation (85 %) was explained by differences between genotypes within populations. Variations among populations within a socioeconomic region (12 %) and among regions (2 %) were less important. This indicated that there is no effect of socioeconomic activity on the distribution of genetic variability.