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This work presents an inventory of the Polyplacophora species registered in December 2019 in the intertidal environment of 10 sampling sites of the Northern Gulf of California, México. Fifteen species were obtained from a total of 33 species previously reported throughout the Gulf. Acanthochitona avicula, Ischnochiton guatemalensis, Lepidozona serrata, and Dendrochiton lirulatus are rare with only 1 to 3 specimens recorded of each species. Stenoplax mariposa and Lepidozona subtilis were the most abundant with 162 and 284 specimens, respectively. Acanthochitona avicula, I. guatemalensis, Lepidozona serrata, and Lepidochitona beanii are rare and each was only recorded at one sampling site. For a better recognition of these species, we provide a dichotomous identification key, which is complemented with high-resolution photographs and images obtained by scanning electron microscopy. In addition, habitat data and taxonomic comments are included to facilitate a better understanding of the habitat preferences, relationships and current taxonomic position of these species.

Husk tomato is an annual vegetable crop grown for its fruits in Mexico, where it grows as weedy and wild. Eight races are recognized from wild (Wild and Milpero) and cultivated (Arandas, Manzano, Puebla, Rendidora, Salamanca, and Tamazula) conditions based on morphological and ecological traits. However, few studies have addressed the genetic diversity and divergence of all races. We aimed to (i) assess the genetic diversity and structure of 10 cultivars representing the recognized races of husk tomato and (ii) compare the genetic diversity of the cultivated and wild pools. We identified 270 single nucleotide polymorphisms from 40 samples using multiplex ISSR genotyping by sequencing (MIG-seq). The results showed lower to moderate diversity in each cultivar (HE = 0.082–0.147) and lower to moderate pairwise genetic differentiation (FST = − 0.011 to 0.195) between cultivars. The Bayesian clustering analysis identified three genetic groups (K = 3) with ancestry coefficients (Q = 0.6–0.89) that suggest gene flow among cultivars. Ordination and classification analysis based on genetic distances revealed two main genetic clusters related to fruit traits and geographic regions where cultivars are commercialized, while a third group included the Wild and Milpero. Analysis of molecular variance revealed higher variation within cultivars (80%) than among cultivars (18%). The cultivated pool harbors 96% of the diversity present in the wild (Ht = 0.322 vs. Ht = 0.311) and does not show severe genetic bottlenecks related to the domestication process. Our results suggest that husk tomato domestication, like other Mesoamerican crops, might be diffuse rather than from a single geographic origin.

Societal Impact Statement Crop wild relatives (CWR) are plant taxa closely related to crops and are a source of high genetic diversity that can help adapt crops to the impacts of global change, particularly to meet increasing consumer demand in the face of the climate crisis. CWR provide vital ecosystem services and are increasingly important for food and nutrition security and sustainable and resilient agriculture. They therefore are of major biological, social, cultural and economic importance. Assessing the extinction risk of CWR is essential to prioritise in situ and ex situ conservation strategies in Mesoamerica to guarantee the long‐term survival and availability of these resources for present and future generations worldwide. Summary Ensuring food security is one of the world's most critical issues as agricultural systems are already being impacted by global change. Crop wild relatives (CWR)—wild plants related to crops—possess genetic variability that can help adapt agriculture to a changing environment and sustainably increase crop yields to meet the food security challenge. Here we report the results of an extinction risk assessment of 224 wild relatives of some of the world's most important crops (i.e. chilli pepper, maize, common bean, avocado, cotton, potato, squash, vanilla and husk tomato) in Mesoamerica—an area of global significance as a centre of crop origin, domestication and of high CWR diversity. We show that 35% of the selected CWR taxa are threatened with extinction according to The International Union for Conservation of Nature (IUCN) Red List demonstrates that these valuable genetic resources are under high anthropogenic threat. The dominant threat processes are land use change for agriculture and farming, invasive and other problematic species (e.g. pests, genetically modified organisms) and use of biological resources, including overcollection and logging. The most significant drivers of extinction relate to smallholder agriculture—given its high incidence and ongoing shifts from traditional agriculture to modern practices (e.g. use of herbicides)—smallholder ranching and housing and urban development and introduced genetic material. There is an urgent need to increase knowledge and research around different aspects of CWR. Policies that support in situ and ex situ conservation of CWR and promote sustainable agriculture are pivotal to secure these resources for the benefit of current and future generations.

Metabolic reconfiguration in plants is a hallmark response to insect herbivory that occurs in the attack site and systemically in undamaged tissues. Metabolomic systemic responses can occur rapidly while the herbivore is still present and may persist in newly developed tissue to counterattack future herbivore attacks. This study analyzed the metabolic profile of local and newly developed distal (systemic) leaves of husk tomato (Physalis philadelphica) plants after whitefly Trialeurodes vaporariorum infestation. In addition, the effect of these metabolomic adjustments on whitefly oviposition and development was evaluated.Our results indicate that T. vaporariorum infestation induced significant changes in husk tomato metabolic profiles, not only locally in infested leaves, but also systemically in distal leaves that developed after infestation. The distinctive metabolic profile produced in newly developed leaves affected whitefly nymphal development but did not affect female oviposition, suggesting that changes driven by whitefly herbivory persist in the young leaves that developed after the infestation event to avoid future herbivore attacks.This report contributes to further understanding the plant responses to sucking insects by describing the metabolic reconfiguration in newly developed, undamaged systemic leaf tissues of husk tomato plants after whitefly infestation. © 2022 Society of Chemical Industry.

Background and Aims Shoot ontogenesis in grasses follows a transition from a vegetative phase into a reproductive phase. Current studies provide insight into how branch and spikelet formation occur during the reproductive phase. However, these studies do not explain all the complex diversity of grass inflorescence forms and are mostly focused on model grasses. Moreover, truncated inflorescences of the non-model grass genus Urochloa (Panicoideae) with formation of primary branches have basipetal initiation of branches. Bouteloua species (Chloridoideae) are non-model grasses that form truncated inflorescences of primary branches with apical vestiges of uncertain homology at the tips of branching events and sterile florets above the lowermost fertile floret. Sterile florets are reduced to rudimentary lemmas composed of three large awns diverging from an awn column. Conflict about the awn column identity of this rudimentary lemma is often addressed in species descriptions of this genus. We test if Bouteloua species can display basipetal initiation of branches and explore the identity of vestiges and the awn column of rudimentary lemmas. Methods We surveyed the inflorescence ontogeny and branch/awn anatomy of Bouteloua species and compared results with recent ontogenetic studies of chloridoids. Key Results Bouteloua arizonica has florets with basipetal maturation. Branches display basipetal branch initiation and maturation. Branch vestiges are formed laterally by meristems during early branching events. The spikelet meristem forms the awn column of rudimentary lemmas. Vestiges and sterile floret awns have anatomical similarities to C4 leaves. Conclusions Basipetal initiation of branches is a novel feature for Chloridoideae grasses. Branch vestiges are novel vegetative grass structures. Sterile floret awn columns are likely to be extensions of the rachilla.

Species delimitation in Cactaceae is a challenging task due to the proliferation of species and subspecies names. Echinocereus pulchellus occurs across a wide geographical range in Mexico and presents numerous polymorphisms. The species complex has been considered to comprise five subspecies. In the present work, we analyze morphological variation across the E. pulchellus complex to establish the taxonomic limits of the complex, to delimit taxa within it, and to determine whether morphological variation is associated with climate variables. Multivariate analyses of 50 morphological characters were conducting in a sample of ten populations representing all five of the previously recognized subspecies of the E. pulchellus complex. The results support the recognition of four distinct species, one of which contains two subspecies, and necessitate three new combinations: Echinocereus acanthosetus, E. sharpii, and E. weinbergii subsp. venustus. Six vegetative and two floral characters define the morphological limits between taxa. Correlation with climate variables was detected in the populations of E. weinbergii.

The Physalis genus includes species of commercial importance due to their ornamental, edible and medicinal properties. These qualities stem from their variety of biologically active compounds. We performed a metabolomic analysis of three Physalis species, i.e., P. angulata, P. grisea, and P. philadelphica, differing in domestication stage and cultivation practices, to determine the degree of inter-species metabolite variation and to test the hypothesis that these related species mount a common metabolomic response to foliar damage caused by Trichoplusia ni larvae. The results indicated that the metabolomic differences detected in the leaves of these species were species-specific and remained even after T. ni herbivory. They also show that each Physalis species displayed a unique response to insect herbivory. This study highlighted the metabolite variation present in Physalis spp. and the persistence of this variability when faced with biotic stressors. Furthermore, it sets an experimental precedent from which highly species-specific metabolites could be identified and subsequently used for plant breeding programs designed to increase insect resistance in Physalis and related plant species.

Some species of Physalis develop fruits that are appreciated as fruit and as culinary ingredients. Only Physalis peruviana and Physalis philadelphica are grown on a larger scale in America. Physalis angulata is grown on a small scale in Jalisco, Mexico. It is a wild species with extensive cultivation potential in tropical areas and a model of wide interest due to its phytochemical, pharmacological, and nutraceutical properties. The objectives of this study were to carry out the agromorphological characterization of wild and weedy populations of P. angulata, to determine if differences exist between both conditions, and to identify populations with outstanding agronomic attributes. Eleven populations were selected that represent the area of Mexico where this species is traditionally cultivated and consumed. A cultivated population was also used for comparison. The characterization was done with 13 descriptors and multivariate methods. A nested PERMANOVA indicated that no significant differences exist between the wild and weedy condition. The classification and ordination analyses confirmed that the condition does not determine the patterns of variation, nor does it explain the formation of the two groups identified. These analyses also demonstrated the variability in the vegetative attributes and fruit in both conditions. In addition, these analyses showed that four populations exhibit similar agronomic characteristics —a greater number of fruits per plant, of larger size (>14 mm) and more weight (>1.5 g), greater precocity (germination 4–7 days), and higher germination percentage (>95%)— to the cultivated populations. The production per hectare estimated for these populations (11–14 and up to 28 t ha−1) is similar to that recorded for other wild tomato species and slightly lower than that of P. philadelphica. Due to their agronomic attributes, these populations can be part of a core collection for a breeding program. The genetic basis of P. angulata is wide and allows the agronomic evaluation and response to nutrition trials of outstanding genotypes, which will favor greater production.

The study of evolutionary history allows us to examine diversification, selection and domestication processes. Mexico belongs to Mesoamerica, one of the world’s most important centers of origin and diversification of plants. One of the plants that has sustained its peoples for over 10,000 years is the agave (Agave sp.). Mexico is the center of diversity of the genus, with 75% of the species. Two agave products, tequila and mezcal, are of great economic and biocultural importance for Mexico. The description of genetic diversity and the identification of the wild relatives of the agave species used to produce these emblematic beverages is fundamental information for their production and conservation. Previous studies have proposed wild populations of A. angustifolia in Jalisco as possible wild relatives of blue agave or tequila (Agave tequilana). We use microsatellite (eight loci) to study the genetic diversity and the relationships between wild populations of A. angustifolia and traditional cultivars of the Agave species utilized in the production of tequila and mezcal in Jalisco. The studied taxa present intermediate genetic variation, with the exception of A. tequilana “Azul” which had the same genotype. A Structure analysis indicates that the “Azul” is closely related to A. angustifolia mainly to wild populations from southern Jalisco. Agave rhodacantha and the cultivars of A. tequilana (“Siguin” and “Chato”) form a group separate from Agave angustifolia y A. tequilana “Azul”.

Background Pseudalcantarea grandis (Schltdl.) Pinzón & Barfuss is a tank bromeliad that grows on cliffs in the southernmost portion of the Chihuahuan desert. Phytotelmata are water bodies formed by plants that function as micro-ecosystems where bacteria, algae, protists, insects, fungi, and some vertebrates can develop. We hypothesized that the bacterial diversity contained in the phytotelma formed in a bromeliad from an arid zone would differ in sites with and without surrounding vegetation. Our study aimed to characterize the bacterial composition and putative metabolic functions in P. grandis phytotelmata collected in vegetated and non-vegetated sites. Methods Water from 10 individuals was sampled. Five individuals had abundant surrounding vegetation, and five had little or no vegetation. We extracted DNA and amplified seven hypervariable regions of the 16S gene (V2, V4, V8, V3–6, 7–9). Metabarcoding sequencing was performed on the Ion Torrent PGM platform. Taxonomic identity was assigned by the binning reads and coverage between hit and query from the reference database of at least 90%. Putative metabolic functions of the bacterial families were assigned mainly using the FAPROTAX database. The dominance patterns in each site were visualized with rank/abundance curves using the number of Operational Taxonomic Units (OTUs) per family. A percentage similarity analysis (SIMPER) was used to estimate dissimilarity between the sites. Relationships among bacterial families (identified by the dominance analysis and SIMPER), sites, and their respective putative functions were analyzed with shade plots. Results A total of 1.5 million useful bacterial sequences were obtained. Sequences were clustered into OTUs, and taxonomic assignment was conducted using BLAST in the Greengenes databases. Bacterial diversity was 23 phyla, 52 classes, 98 orders, 218 families, and 297 genera. Proteobacteria (37%), Actinobacteria (19%), and Firmicutes (15%) comprised the highest percentage (71%). There was a 68.3% similarity between the two sites at family level, with 149 families shared. Aerobic chemoheterotrophy and fermentation were the main metabolic functions in both sites, followed by ureolysis, nitrate reduction, aromatic compound degradation, and nitrogen fixation. The dominant bacteria shared most of the metabolic functions between sites. Some functions were recorded for one site only and were related to families with the lowest OTUs richness. Bacterial diversity in the P. grandis tanks included dominant phyla and families present at low percentage that could be considered part of a rare biosphere. A rare biosphere can form genetic reservoirs, the local abundance of which depends on external abiotic and biotic factors, while their interactions could favor micro-ecosystem resilience and resistance.

espanolEl papel funcional de las bacterias asociadas a corales y su contribucion a la salud del coral es aun desconocido en gran medida. Es necesario que primero se caracterice el ensamblaje microbiano del coral y sus cambios en la diversidad a traves de las especies de coral, el espacio y tiempo. Los corales ramificados (e.g., genero Pocillopora) son los principales constructores arrecifales a nivel mundial. Este estudio evaluo la estructura bacteriana asociada al mucus y tejidos de Pocillopora damicornis y Pocillopora verrucosa, asi como del agua de mar y sedimentos circundantes en 6 sitios del Pacifico central mexicano. Se emplearon las tecnicas DGGE y RFLP del ADNr 16S para generar los perfiles de bandeo o evaluar la diversidad. Ademas, se evaluo la relacion del ensamblaje bacteriano-coral con variables ambientales y espaciales del entorno arrecifal (de cada sitio), utilizando analisis multivariados. Se obtuvieron 20 Unidades Taxonomicas Operacionales (OTU) diferentes, siendo los sedimentos los que presentaron mayor numero. Se encontro una especificidad de grupos bacterianos para cada especie de coral, asi como entre el tejido y mucus de cada especie. Los resultados mostraron que los grupos de bacterias dominantes variaron entre sustratos y entre sitios, encontrando, solo una variacion espacial significativa. Las variables ambientales que explican la variacion de los grupos bacterianos dominantes en corales y agua de mar fueron las coberturas de macroalgas carnosas, coral vivo y esponja. En cambio, la variacion en los sedimentos fue explicada por las coberturas de arena, escombro y roca. EnglishThe functional role of coral-associated bacteria and their contribution to coral health is still largely unknown. The first necessary step to address this gap in the knowledge is based on characterization of the microbial assemblage of the coral and the species-specific, temporal and spatial variation in its diversity. Branched corals (e.g., genus Pocillopora), are the main builders of coral reefs worldwide. This study evaluated the bacteria associated with the mucus and tissues of Pocillopora damicornis and Pocillopora verrucosa, as well as that of the seawater and surrounding sediments, in 6 sites of the Mexican Central Pacific during summer and winter seasons. The molecular techniques DGGE and RFLP were used with the 16S rDNA to assess the most abundant bacterial OTUs. The relationships between the bacterial-coral assemblage and environmental and spatial variables of the reef surroundings were also evaluated, using the multivariate analyses. Twenty different Operational Taxonomic Units (OTU) were obtained, with the highest number presented by the sediments. Specificity of bacterial groups was found for each coral species, as well as between the tissue and mucus of each species. The results showed that the bacterial dominant groups were similar between seasons, but these showed significant spatial variations among substrates within sites, as well as per substrate across all sites. The environmental variables that explained the variation of the dominant bacterial groups in corals and sea water were the coverages of fleshy macroalgae, live coral and sponge. In contrast, variation in the sediments was explained by the coverages of sand, rubble and rock.

Background: Knowledge on Mexican Solanaceae is uneven. Several areas are well collected and have been floristically treated in recent times, but others have been neglected and are poorly represented in herbaria. Question: Which species of Solanaceae grow in Mexico and which is their state distribution. Study site: Mexico from 2009 to 2011. Methods: We reviewed family literature as well as Mexican and North American herbaria. We analyzed species distribution for each state, and endemism for the country and MegaMexico. Results: We found three subfamilies (Cestroideae Juanulloideae and Solanoideae), 34 genera, 381 species, and 18 varieties. We include state distributions and endemism for the country, as well as for MegaMexico 1, in which the natural limits of the Sonoran, Chihuahuan, and Tamaulipean deserts are included, and MegaMexico 2 which includes Central America up to northern Nicaragua. There are no endemic genera to Mexico, but Nectouxia, Datura and Chamaesaracha are endemic to MegaMexico 1, and Plowmania , Tzeltalia, Capsicophysalis and Schraderanthus are endemic to MegaMexico2. Three genera, Brugmansia, Petunia and Nicandra are introduced and have naturalized species. Solanum has the highest number of species (130), then Physalis with 65, and Cestrum 42. Mexico harbors all the species of Datura and Tzeltalia , 80 % of Chamaesaracha and 77 % of Physalis . As to state richness, Oaxaca has 172 species, Chiapas 167, Jalisco 148, and Veracruz 145. The states with less species are Tlaxcala with 16, Campeche with 19, and Colima with 27. Conclusions: Mexico is an important center of diversity and endemism of Solanaceae. One hundred thirty-five species are endemic to Mexico, with eight varieties. MegaMexico 1 has 30 endemic species with two varieties, and MegaMexico 2 has 57 endemic species. Endemism figures will probably vary once nomenclatural problems of under collected 2 has 57 endemic species. Endemism figures will probably vary once nomenclatural problems of under collected taxa are resolved.

The Mexican Central Pacific is located in a zone of oceanographic transition between two biogeographic provinces with particular conditions that affect the associated fauna. The objective of this study was to evaluate the variation of hermatypic coral assemblages in this region and to determine their relationship with the heterogeneity of the benthonic habitat and spatial variables. A total of 156 transects were carried out at 41 sites in the years 2010 and 2011. The sampling effort returned 96.7% of the coral richness expected for the area, with a total of 15 species recorded. The results showed that richness, diversity and cover of corals varied only at the site and state scales. However, the composition and coverage of all coral species, as well as the benthonic habitat structure, differed significantly across the study scales (i.e. sites, zones and states). Canonical redundancy analysis showed that variation in the richness, diversity and assemblages of corals was explained by the cover of live corals, articulated calcareous algae, sandy substrate, sponges and fleshy macroalgae. This study suggests that local scale (i.e. site) variation in the coral assemblages of the Mexican Central Pacific is the result of the heterogeneity of the benthonic habitat, while geomorphological and oceanographic characteristics play a greater role at regional scale. El Pacífico Central Mexicano se localiza en una zona de transición oceanográfica entre dos provincias biogeográficas con condiciones ambientales particulares que afectan la fauna asociada. El objetivo del estudio fue evaluar la variación de las comunidades de coral hermatípico de esta región y determinar su relación con la heterogeneidad del hábitat bentónico y variables espaciales. Se realizaron 156 transectos en 41 sitios en los años 2010 y 2011. El esfuerzo de muestreo representó el 96.7% de la riqueza de coral esperada para el área, con un total de 15 especies registradas. Los resultados mostraron que la riqueza, diversidad y cobertura de corales variaron sólo en las escalas de sitio y de estado. En cambio, la composición y cobertura de todas las especies de coral, así como la estructura del hábitat bentónico, fueron significativamente diferentes en todas las escalas estudiadas (i.e. sitio, zona y estado). Los análisis de redundancia canónica mostraron que la variación de la riqueza, diversidad y de las comunidades de corales eran explicadas por la cobertura de coral vivo, algas calcáreas articuladas, sustrato arenoso, esponjas y macroalgas carnosas. Este trabajo sugiere que la variación de las comunidades de coral en el Pacífico Central Mexicano a escala local (i.e. sitio) se debe a la heterogeneidad del hábitat bentónico, mientras que a escala regional, las características geomorfológicas y oceanográficas desempeñan un papel más importante.

Physalis chenopodifolia is a perennial wild tomatillo with traditional use in central Mexico because of its edible fruits. Due to their agronomic potential and nutraceutical properties, thi...

The complex evolutionary history of the subtribe Physalinae is reflected in the poor resolution of the relationships of Physalis and the physaloid genera. We hypothesize that this low resolution is caused by recent evolutionary history in a complex geographic setting. The aims of this study were twofold: (1) To determine the phylogenetic relationships of the current genera recognized in Physalinae in order to identify monophyletic groups and resolve the physaloid grade; and (2) to determine the probable causes of the recent divergence in Physalinae. We conducted phylogenetic analyses with maximum likelihood (ML) and Bayesian inference with 50 Physalinae species and 19 others as outgroups, using morphological and molecular data from five plastid and two nuclear regions. A relaxed molecular clock was obtained from the ML topology and ancestral area reconstruction was conducted using the DEC model. The genera Chamaesaracha, Leucophysalis, and Physalis subgenus Rydbergis were recovered as monophyletic. Three clades, Alkekengi-Calliphysalis, Schraderanthus-Tzeltalia, and Witheringia-Brachistus, also received good support. However, even with morphological data and that of the DNA of seven regions, the tree was not completely resolved and many clades remained unsupported. Physalinae diverged at the end of the Miocene (∼9.22Mya) with one trend indicating that the greatest diversification within the subtribe occurred during the last 5My. The Neotropical region presented the highest probability (45%) of being the ancestral area of Physalinae followed by the Mexican Transition Zone (35%). During the Pliocene and Pleistocene, the geographical areas where species were found experienced significant geological and climatic changes, giving rise to rapid and relatively recent diversification events in Physalinae. Thus, recent origin, high diversification, and morphological complexity have contributed, at least with the currently available methods, to the inability to completely disentangle the phylogenetic relationships of Physalinae.

Hylocereus en un género americano de importancia hortícola por sus frutos comestibles. En México crecen varias especies de Hylocereus . Sin embargo, su distribución no se conoce por completo, por ello se requiere ampliar este conocimiento. Con este objetivo se analizaron la riqueza de especies y los patrones de distribución geográfica de Hylocereus en México. Se revisaron ejemplares de 12 herbarios nacionales y se hicieron colectas botánicas. En adición, con un Sistema de Información Geográfica y 437 registros georeferenciados se identificaron las provincias biogeográficas y condiciones ecológicas en que se desarrollan. Como resultado, se reconoció a H . ocamponis , H . purpusii , H . undatus e H . aff. escuintlensis . Jalisco, Chiapas y Oaxaca tienen el mayor número de registros y junto con Michoacán y Guerrero son los de mayor riqueza. Los cuatro taxa se desarrollan en la Costa Pacífica Mexicana mientras H . purpusii , H . ocamponis y H . undatus confluyen en el Eje Volcánico Transmexicano. Hylocereus aff . escuintlensis e H . undatus convergen en la provincia de Chiapas. Hylocereus crece en climas templados a muy cálidos; H . undatus exhibe la mayor amplitud ecológica, H . aff . escuintlensis muestra intervalos más estrechos mientras que H . ocamponis e H . purpusii coexisten en condiciones similares.

Centers of origin of agriculture and domestication have significantly contributed to the evolution of landraces, based on a long history of use and management of both wild and crop species. Our study examines Physalis angulata, an emerging horticultural crop in western Mexico. This wild and weedy species was adopted as an alternative crop to P. philadelphica for producing husk tomato. We investigated: (1) the antiquity of use of this species as a crop and the origin of the cultivated germplasm, (2) the criteria for selection and cultivation techniques and (3) its horticultural value. We conducted field trips to the husk tomato-producing areas of Cuquio and Ixtlahuacan, Jalisco to identify the producers who grow it. We used participant observation, open interviews and semi-structured surveys with producers in order to document ethnobotanical knowledge, plant management and agronomical issues. We found that P. angulata is cultivated in 80 % of the visited plots; the producers report that it has been actively cultivated for 25 years. With the available information, the origin of the cultivated germplasm has not been accurately determined; however, some locations in Michoacan and Cuquio in Jalisco could be putative areas of origin. The crop was introduced by the commercial demand for “milpero” a kind of husk tomato of small fruit and high commercial value. It is established in 0.5 ha monoculture plots. Its small-scale cultivation favors greater yields. The cultivation of P. angulata could be promoted in other tropical and temperate areas of the Americas as a new crop of Solanaceae; their self-compatibility, synanthropy, high yield and compact canopy could be of commercial interest to husk tomato producers.

Agave potatorum is a wild endemic species of Mexico. Its stems are used for mescal production, which cancels sexual reproduction. Agaves extraction from forests decreases their reproductive success and demographic performance. We evaluated patterns of genetic diversity and structure of wild populations under and without extraction in order to identify effects of its use and actions required for conserving genetic variation. This study was conducted with seven SSR markers in 12 populations representing the entire distribution area of the species. Standard parameters of genetic diversity, differentiation, structure and genetic similarity of populations were calculated and analyzed. The populations studied showed intermediate to high genetic diversity (H e = 0.36–0.64), compared with other Agave species so far studied. The wild category was the most diverse (H T = 0.87), but without significant differences with respect to populations under extraction (H T = 0.72), and two germplasm banks sampled (H T = 0.69). High structure among populations (Φ PR = 0.38) and inbreeding levels (F IS = 0.26, F IT = 0.55) were identified; a 3 % of genetic diversity being distributed among management status where germplasm banks represent a genetic pool with incipient divergence from the other categories. Bayesian analysis indicated two genetic groups. Our study suggests slight effects of management on genetic diversity of A. potatorum, apparently related to alterations of reproductive biology and pollination patterns.

Population genetic structuring is common among herbivorous insects and frequently is associated with divergent host plants, such as crops and their wild relatives. Previous studies showed population genetic structuring in corn leafhopper Dalbulus maidis in Mexico, such that the species consists of two sympatric, host plant-associated populations: an abundant and widespread “pestiferous” population on maize (Zea mays mays), and a small and localized “wild” population on perennial teosinte (Zea diploperennis), a maize wild relative with a limited distribution. This study addressed whether assortative mating and immigrant inviability mediate genetic structuring of corn leafhopper by comparing the mating and reproductive successes of pestiferous and wild females that colonize their non-associated host plants against the successes of females colonizing their associated host plants. Assortative mating was assessed by comparing mating frequencies and pre-mating and mating times among females of each population on each host plant; immigrant inviability was assessed by comparing, across two generations, the fecundity, survival, development time, sex ratio, and population growth rate among leafhopper populations and host plants. Our results showed that on maize, and compared to resident, pestiferous females, wild females were more likely to mate, and greater proportions of their offspring survived to adult stage and were daughters; consequently, the per-generation population growth rate on maize was greater for immigrant, wild leafhoppers compared to resident, pestiferous leafhoppers. Our results suggested that wild leafhoppers emigrating to maize have a fitness advantage over resident, pestiferous leafhoppers, while immigrant pestiferous and resident wild leafhoppers on teosinte have similar fitnesses. This article is protected by copyright. All rights reserved

Physalis is an American plant genus that includes species of economic importance for their edible fruit. Consumption of this fruit is a historic tradition in Mexico. Physalis philadelphica is one of the most abundant species, which can grow under wild, weedy or cultivated conditions. It presents high morphological variability in terms of vegetative and reproductive traits; however, no study has been made of its genetic diversity or the impact of human activity on its diversity and differentiation patterns. We determined genetic parameters in nine populations representing a management gradient, including three wild, three weedy and three cultivated populations, using 88 inter-simple sequence repeat markers. The diversity of the total gene pool was high (Ht = 0.292, HT B = 0.319) and did not decrease with the intensity degree of management. Reproductive system, life form and the wide distribution determined the genetic variation of the taxon. AMOVA revealed high variation within the total gene pool (44.3 %) and among populations (46.7 %). This was influenced by pollinator behavior, dispersal form, geographic discontinuity of the studied populations and human selection. Variation among population management categories was lower (9 %), indicating that this variable has little effect, most likely due to the broad gene pool of the taxon. However, analysis of genetic distance and Bayesian assignment distinguished two groups: cultivated and wild, with weedy populations interspersed between. This result suggests that selection for agricultural and morphological attributes of P. philadelphica contributes to this differentiation. Future studies could address the evolutionary dynamics of the wild–weedy–domesticated complex.

Over the last 30 years, cultivation of Agave tequilana Weber var blue for industrial production of tequila, has generated soil erosion, chemical pollution, displacement of traditional food crops and traditional Agave landraces used for preparing “mezcals” in the Appellation of Origin Tequila area. It is also associated with harmful cycles 8–10 years long of surplus-shortfall availability of raw material. Mezcal is the common traditional name given in Mexico to spirits like tequila, prepared with Agave tissue. We examined the traditional strategies of management of the Agave genetic resources for elaborating mezcal and tequila spirits by people of southern Jalisco, Mexico, analyzing the bases of their sustainable management, compared with management of the industrial tequila system. We found that mezcal spirits are prepared with different landraces of A. angustifolia Haw. and A. rhodacantha Trel. which are cultivated as living fences within the “milpa”, the traditional Mesoamerican multi-crop system. The whole system allows simultaneous production of agricultural, livestock and forest resources, permitting the adjustment of mezcal production to demand. Agave borders and terraces are laid out perpendicular to slopes to increase rainfall capture and filtration, and decrease soil erosion. The high species richness creates niche heterogeneity, substantially reducing pest and disease incidence. Genetic and morphological analyses indicated that traditional management and selection of A. angustifolia landraces have produced high genetic diversity (HBT = 0.438 ± 0.003) and structure (θB = 0.408) when compared with wild populations (HBT = 0.428 ± 0.015; θB = 0.212). Morphological differentiation is associated to artificial selection pressures. Differential precocity of Agave landraces and scaled planting favors continuous, year round spirit production. Growers directly market their mezcals, and a portion of the profits is reinvested in the parcel to ensure system continuity. The technological advantages of the traditional mezcal system could attenuate some challenges caused by the tequila industrial agriculture.

Mexico is the center of diversity of the husk tomato (Physalis L., Solanaceae), which includes a number of commercially important edible and ornamental species. Taxonomic identification is presently based on morphological characteristics, but the presence of high inter- and intraspecific morphological variation makes this task difficult. Six ISSR primers were used on eight Mexican species of Physalis to determine their utility for interspecific taxonomic discrimination and to assess their potential for inferring interspecific relationships. The six ISSR primers amplified 101 bands, with 100% polymorphism across samples. The number of bands per primer varied from 10 to 21. All primers produced different fingerprint profiles for each species, confirming the ISSR value in taxonomic discrimination. Discrimination values based on Simpson’s diversity index varied from 0.48 to 0.58. Genetic interspecific similarity values ranged from 0.20 to 0.57, and intraspecific similarity values were highest for Physalis angulata (0.71), followed by Physalis philadelphica (0.63) and Physalis lagascae (0.55). The UPGMA analysis grouped accessions of the same species together and clustered together Physalis species of similar morphological traits. Thus, ISSR markers are useful in estimating genetic relationships in Physalis.

Traditional farming communities frequently maintain high levels of agrobiodiversity, so understanding their agricultural practices is a priority for biodiversity conservation. The cultural origin of agave spirits (mezcals) from west-central Mexico is in the southern part of the state of Jalisco where traditional farmers cultivate more than 20 landraces of Agave angustifolia Haw. in agroecosystems that include in situ management of wild populations. These systems, rooted in a 9000-year-old tradition of using agaves as food in Mesoamerica, are endangered by the expansion of commercial monoculture plantations of the blue agave variety ( A. tequilana Weber var. Azul), the only agave certifi ed for sale as tequila, the best-known mezcal. Using intersimple sequence repeats and Bayesian estimators of diversity and structure, we found that A. angustifolia traditional landraces had a genetic diversity ( H BT = 0.442) similar to its wild populations ( H BT = 0.428) and a higher genetic structure ( θ B = 0.405; θ B =0. 212). In contrast, the genetic diversity in the blue agave commercial system ( H B = 0.118) was 73% lower. Changes to agave spirits certifi cation laws to allow the conservation of current genetic, ecological and cultural diversity can play a key role in the preservation of the traditional agroecosystems.

Extensive monovarietal cultivation of Age tequilana Weber var. azul is threatening the diversity of the germplasm used in traditional Agave spirits production in west-central Mexico. To promote the preservation, use, and management of this germplasm, an ethnobotanical and morphological study was done in the center and south of the state of Jalisco, Mexico. The richness, distribution, and morphological variation of wild and cultivated Agave populations were characterized, and producers’ roles in germplasm maintenance and diversification were analyzed. Results indicated that: 1) A. angustifolia and A. rhodacantha are the primary gene pools used for selection; 2) Traditional landraces are differentiated morphological entities; and 3) In situ maintenance and increase of Agave germplasm diversity are the result of constant selection of wild germplasm, producer management of populations in the wild-domesticated gradient, and preservation of old landraces. Preservation of Agave germplasm diversity in west-central Mexico requires increased cultivation and valuation of traditional landraces.