Sergio Segura

An AFLP diversity study of the genus Passiflora focusing on subgenus Tacsonia

DNA variation was studied at the intra- andinterspecific levels within the genus Passiflora, with particular emphasis on the subgenusTacsonia and its relationship with the subgenusPassiflora. AFLP fingerprints were generated for35 accessions from 21 species, 14 of which belong to subgenusTacsonia, and four to subgenusPassiflora. The morphologically intermediateP. manicata (subgenusManicata) was also included, as wereP. trinervia (subgenusPsylanthus) and P.alnifolia (subgenus Decaloba). The two latter were used as outgroup species. Twoprimer combinations generated 34–80 scorable fragments pergenotype for a total of 260 fragments. Polymorphism analyses spannedthe levels from individual genotype to section. SubgenusTacsonia presented wide genetic variability atboth intra- and interspecific levels, particularly within wildspecies. The classification based on these markers generally agreeswell with current taxonomic definitions of common species, but lesswith definitions of sections. A geographical component was evident inthe intraspecific variation of P.mixta, P.tripartita var. mollissimaand P. tarminiana, withwider variation in Ecuador and Peru than in Colombia and Venezuela.These same three species, plus P.cumbalensis, formed adjacent clusters, showingcloser affinity with each other than with the other species ofsubgenus Tacsonia. As expected, P. manicata clustered at anintermediate position between subgenera Tacsoniaand Passiflora.

Mapping the potential distribution of five species of #Passiflora# in Andean countries

Geographic location data for 383 accessions of five Passiflora species from five Andean countries (P. cumbalensis, P. mixta, P. tripartita var. mollissima, P. natistipula, and P. manicata) were linked to interpolated continental surfaces of monthly mean rainfall, monthly mean temperature, and monthly mean diurnal temperature range. This permitted us to identify the potential distribution of each species and document its climatic adaptation. Maps are presented showing regions where the climate is similar to that in areas where each species has been found, but from which no collections have yet been made, thus representing possible geographical gaps in collections. Some species showed evidence of intra-specific variation in their climatic adaptation. The study of Passiflora diversity in Andean countries continues and these maps based on passport data are expected to be useful tools for the planning of both ex situ and in situ conservation activities.

Morphovariability of capulín (Prunus serotina Ehrh.) in the central-western region of Mexico from a plant genetic resources perspective

The capulín, or black cherry tree (Prunus serotina Ehrh.) is a tree with edible fruits native to North America that has been used not just as a source of food but also as a source of energy (its wood) since prehispanic times. Mexico has three of the five botanical subspecies in the P. serotina botanical complex, which have not yet been characterized for agricultural purposes. It is desirable to determine whether capulín trees comprise a homogeneous group or whether there are separate morpho-types. This study focuses on the morphological variability of seven populations from the western and central regions of Mexico. We used the Hill & Smith Analysis and graphical methods to analyze and interpret data with respect to 22 quantitative morphological characters and 17 qualitative morphological characters, all from different plant organs. Two major geographically and morphologically related groups were clearly identified, and the morphological variability in the study zone was related to taxonomic, genetic and agronomic factors. The results are discussed from a genetic resources perspective. The genetic, cultural, ecological and agronomic implications of these results are also considered, as well as the potential uses for the species. From these results, an agro-morphological characterization can be developed, in order to identify interesting types of capulín for fruit and seed production in agro-industry, or as rootstock for related species and forestry uses. Our results have implications for the conservation and sustainable use of capulín genetic resources in the central and western regions of Mexico.

Morphological variation in black cherry (Prunus serotina Ehrh.) associated with environmental conditions in Mexico and the United States

Black cherries are native to North America and make up a complex of five morphologically different subspecies growing in significantly different niches. This study used 474 presence points, 19 climate parameters and altitude to: (1) describe climatic preference of subspecies, (2) associate the most discriminant bioclimatic variables with variation of 17 quantitative morphological descriptors and (3) estimate the potential effect of climate change in the distribution areas of the complex. Altitude and seven climatic parameters played a considerable role in the differentiation of subspecies (subsp.). Climate variability indicated that subsp. eximia, hirsuta and serotina are distributed in more humid and cold environments, while subsp. virens prefers drier and warmer environments. Subspecies capuli exhibited the greatest environmental heterogeneity. Morphological differences included longer, wider leaves and thicker fruit pedicel in subsp. capuli and shorter, smaller leaves in ssp. virens. Even though morphological variation associated with climate was relatively low, the study did show possible effects of climatic variability on morphology and distribution of the P. serotina complex and provided reference information that may be useful for an integrated description of its genetic resources. Climate change could cause genetic erosion due to the loss of suitable habitats. Studies on population genetics can increase understanding of the P. serotina complex and favor efficient strategic guidelines for use and conservation of these resources.