VARIABILITY ANALYSIS OF WILD GUATEMALAN AVOCADO GERMPLASM BASED ON AGRO-MORPHOLOGICAL TRAITS

Abstract

Background. For the Guatemalan culture, the avocado (Persea americana Mill) represents more than a crop, since it has religious, mythical, economical, and medicinal significance typical of the center of domestication of the species. Although there is speculation about the wide variability of wild avocado germplasm, there are no studies describing avocado populations. Objective. To explore wild germplasm based on agro-morphological characteristics using the standardized descriptors for avocado (Persea spp.). Methodology. The distribution of characteristics of 189 avocado trees across eight populations was evaluated using cross-tabulation and Chi-square testing. In order to properly handle qualitative and quantitative data, it was employed the factor analysis of mixed data (FAMD) and hierarchical clustering on principal components (HCPC) to analyze the relationship and variation of features within and between populations. Results. The samples showed various morphological characteristics that indicate the presence of Mexican, Guatemalan, and West Indian avocado races in Guatemala. The FAMD revealed that the fruit shape, skin color and flesh texture, and anise odor in the leaves are ideal traits for distinguishing between individual trees. At the population level, the HCPC showed considerable variance amongst the studied trees but no distinct geographic groups of the samples. Implications. Although not all wild avocados grown in Guatemala are of the highest quality, several trees of extraordinary excellence are strewn over the republic's highlands. Thus, due to the danger posed by the introduction of commercial varieties, it is advisable preserving the germplasm. Conclusion. The clustering methods revealed that the 189 avocado trees could be regrouped into three main clusters. The morphological descriptors proved to be useful for grouping trees according to known races and can therefore be used in the characterization of cultivars and wild trees whose ancestry is unknown.

Keywords

• persea americana
• diversity
• phenotypic variation
• factorial analysis of mixed data
• wild germplasm
• conservation