Guatemala’s wild avocado germplasm holds vital genetic value, but lacking conservation strategies imperils it. Studying its diversity is pivotal for conservation and breeding. The study aimed to comprehensively assess the wild avocado germplasm in Guatemala by combining phenotypic and genotypic data and to create a core collection for conservation and future breeding programs. A total of 189 mature avocado trees were sampled across Guatemala’s northern, southern, and western regions. Morphological characteristics were documented, and genetic diversity was assessed using 12 SSR loci. The investigated germplasm revealed three distinct genetic clusters, exhibiting an average gene diversity of 0.796 and a 7.74% molecular variation among them. The samples showed various morphological characteristics that indicate the presence of three avocado races in Guatemala. The weak correlation between phenotypic and genotypic distances highlighted their independence and complementary nature. The joint matrix effectively integrated and captured genotypic and phenotypic data for comprehensive genetic diversity analysis. A core collection comprising 20% of total accessions that captured maximum genetic diversity was formed. This study exposed wild Guatemalan avocados’ genetic diversity, morphological traits, and conservation significance. Integrated data capture via clustering validates holistic genetic insight for conservation and breeding strategies.

The tree composition in cocoa agroforestry systems (CAFS) in Guatemala is valued for providing a number of ecosystem services. Despite the importance of the trees in these systems, little is known about the tree species richness and its contribution to the conservation of diversity. We studied the botanical composition of CAFS of different ages in the Alta Verapaz department of Guatemala. In total, 70 survey plots with a size of 2500 m² were established. An inventory was carried out in each sampling unit, recording the tree species present and measuring the diameter at breast height (DBH 1.30 m) and the height of each tree. The Importance Value Index (IVI) was calculated and species richness and the similarity between sites were evaluated. A total of 2519 trees, belonging to 59 species and 34 families were identified. The species with the highest IVI was Gliricidia sepium (Jacq.) Kunth. The CAFSs with the highest and lowest species richness were those of 9-12 and 27 years old, respectively (H´=1.99, H´=0.34). This behavior can be explained by the fact that growers work to enrich the agroforestry systems with a broad diversity of species in the first years which they then begin to harvest at around 16 years of age. A discriminant analysis of principal components (DAPC) and the Jaccard Similarity Index were used to show that several AFS were similar in terms of composition and botanical diversity. Given the tree diversity within the CAFS, these can be acknowledged as areas with good potential for the conservation of overall biodiversity. We recommend education programs for local growers about the benefits of shade management during the production cycle of cocoa to preserve the botanical composition and structural complexity of the AFS.

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.

Timber production in agroforestry systems can improve environmental and economic sustainability, especially for families living in rural areas. Despite its importance in Guatemala, little is known about the potential of wood and its contribution to the sustainability of traditional agroforestry systems. This study aims to analyze the timber resources in cocoa agroforestry systems (CAFS) of different ages, evaluating variables such as floristic composition, species diversity, and the potential to obtain timber from the species present in the evaluated CAFS. Twenty temporary sampling plots of 2,500 m2 were established, and dendrometric variables were measured in all plots. Species occurrence was statistically analyzed by cross-tabulation and Pearson's Chi-square test (χ2) to determine species' frequency distribution among the evaluated CAFS ages. Eight hundred twenty-seven trees of 38 species belonging to 19 families were identified. The most represented species in the age range of the evaluated CAFS were Gliricidia sepium (35.07 %), Swietenia macrophylla (19.11 %), and Inga sapindoides (7.62 %). The total shade trees occupied a basal area of 33.29 m2, and a total volume of 352.35 m3 was recorded, of which 148.9 m3 were for commercial use. The most frequent uses of the wood were firewood (38.21 %), thin plank (30.23 %), and poles (22.85 %), while the use of thick plank was the least common (8.71 %). The CAFS in the studied area are characterized by a wide diversity of shade tree species. These results provide a solid basis for promoting sustainable practices that foster the productivity and preservation of these systems, thus contributing to the sustainability and well-being of farmers.

The fruit of the allspice tree (Pimenta dioica (L.) Merr.) is a valuable non-timber forest product traded for its flavour, oils and secondary metabolites. Intense selection pressure from traditional harvesting methods has favoured low-height, high-yield phenotypes, potentially impacting genetic diversity. Although phenotypic variations have been observed, no baseline molecular genetic assessments have been conducted in Guatemala to evaluate the impact of these practices. This study assessed the genetic diversity and structure of natural and cultivated populations of allspice in Guatemala using molecular markers. Seven populations from northern Guatemala, representing a range of ecological conditions, were analysed using 15 random amplified polymorphic DNA (RAPD) primers. A total of 126 amplified fragments, with 88.1 % polymorphism, were obtained. The RAPD markers showed high levels of polymorphism (Polymorphic information content (PIC) = 0.331), good discriminatory power (D = 0.907) and reasonable resolving power (Rp = 3.976). Estimates of genetic diversity, based on Nei’s gene diversity (He) and Shannon’s diversity index (H), were slightly higher in natural populations (He = 0.24–0.28; H = 0.35–0.40) than in cultivated populations (He = 0.17–0.22; H = 0.23–0.31), suggesting that natural populations maintain greater genetic variability, due to lower levels of human intervention. Population structuring methods, unweighted pair group method with arithmetic mean (UPGMA), discriminant analysis of principal components (DAPC), sparse non-negative matrix factorisation (sNMF)) revealed genetic similarity among most populations, with San Cristobal being the exception, showing significant differentiation (p < 0.05). These findings highlight the importance of implementing integrated conservation strategies (in situ, circa situ and ex situ methods), as well as sustainable management of naturally regenerated and cultivated populations, to preserve the Guatemalan gene pool of P. dioica.