Instituto Canario de Investigaciones Agrarias

In this study, we conducted a comprehensive characterization of avocado accessions from the Canary Islands, focusing on molecular, morphological, phenological, and agronomic traits. A total of 311 trees were initially prospected across Tenerife, La Palma, Gran Canaria, and La Gomera Islands. DNA was extracted from young leaves, and genetic diversity was assessed using 28 microsatelites primers, 14 of which were highly polymorphic, revealing 6937 amplified fragments, 137 of which were polymorphic. The average polymorphism percentage was 85.68%, with an expected heterozygosity of 0.68, indicating high genetic diversity. A dendrogram based on genetic data identified four main groups, two of which are closely related to the most widely cultivated avocado cultivars: ‘Hass’, ‘Fuerte’, and ‘Pinkerton’. Morphological analysis (over three years), using 91 descriptors, revealed a clear differentiation between accessions, with several groups corresponding to specific commercial cultivars. Morphotypes that deviated from the main groupings were specimens obtained through sexual propagation. Principal component analysis revealed that fruit characteristics such as length-to-diameter ratio, seed size, and fruit weight were the most discriminating traits, consistent with findings in the Persea genus. These results highlight the genetic and morphological diversity within the Canary Islands avocado germplasm, providing valuable insights for future breeding and conservation efforts.

Abstract Purpose Organic amendments (OAs) from agricultural and livestock residues are usually used to improve soil fertility in crop systems, however, the knowledge of the banana agroecosystem remains limited. The aimed of this study was to evaluate and compare the effect of four OAs commonly used in Canary Islands, on soil health and plant performance. Methods A two-year greenhouse experiment was carried out over a complete crop cycle. The treatments included cow manure, chicken manure, compost, pelletised compost, and a non-amended control. Soil chemical properties, microbial activity, plant growth, and plant nutrient content were monitored across the experiment. Results All OAs improved soil parameters relative to the control, with differing impacts among treatments. Chicken manure markedly enhanced soil microbial activity (increasing induced respiration and the abundance of bacterial, actinobacterial, and fungal populations), increased phosphorus and electrical conductivity, and reduced pH (by up to 1.5 units). Cow manure increased soil nutrient availability (especially nitrogen and phosphorus) and stimulated basal microbial respiration. Compost promoted fungal abundance and increased total and oxidisable organic matter throughout the crop cycle, whereas pelletised compost showed variable effects. In terms of plant development, chicken and cow manure significantly improved height, biomass, pseudostem circumference, and leaf area. Chicken manure outperformed cow manure in several yield-related parameters, including bunch and hand weight, number of fingers/hand, finger size, and rachis diameter. At harvest, chicken manure also showed the highest uptake of calcium, iron, manganese, nitrogen, potassium, sodium, and zinc. Conclusions These results highlight the different effects of each OAs and their specific potential to improve soil biological parameters, nutrient availability, and banana yield as effective tools to enhance agroecosystem sustainability. Graphical Abstract

Echium species, abundant in the Canary Islands, contain unique fatty acids (FA) such as stearidonic acid (SDA; 18:4n-3) and γ-linolenic acid (GLA; 18:3n-6), which may improve egg quality while valorizing local genetic resources. This study evaluated the effects of Echium plantaegineum oil (EO) compared with linseed oil (LO) and soybean oil (SO) on productive performance, egg quality, sensory traits, and yolk fatty acid profile. Forty-eight hens from the Canary Islands were fed for 31 days with diets supplemented with 1.25% SO (SO-d), 1.1% LO + 0.15% beef tallow (LO-d), and 1% EO + 0.25% LO (EO-d). LO supplementation reduced laying rate and egg mass with respect to SO, increasing feed conversion ratio (FCR), whereas EO produced slightly lighter eggs compared to the SO group but with normal yolk proportion and shell traits. EO markedly increased egg yolk deposition of SDA, eicosapentaenoic acid (EPA; 20:5n-3), docosapentaenoic acid (n-3 DPA; 22:5n-3), and docosahexaenoic acid (DHA; 22:6n-3), while lowering the n-6/n-3 ratio and thrombogenic index (TI). No differences were observed in the evaluated sensory attributes among treatments. In conclusion, dietary inclusion of EO effectively enriches eggs with n-3 LC-PUFA without negatively affecting sensory quality, supporting its potential use as a functional ingredient in laying hen diets.

Avocado (Persea americana Mill.) is cultivated in a wide range of environments, from tropical and semitropical to subtropical regions. Its fruit, of high nutritional value, is increasingly demanded worldwide. Spain is the main European producer, but avocado cultivation in certain areas, such as the Canary Islands, requires the genetic identification of West-Indian rootstocks because they often show tolerance to low-quality water and soil salinization. In the present study, eight novel Retrotransposon-Based Insertion Polymorphism assays, derived from previously characterized inter-Primer Binding Site markers, have been developed and evaluated by multiplex PCR across 58 P. americana cultivars. The results showed 100% specificity and sensitivity in detecting the West-Indian genomic component, both in pure and hybrid avocado cultivars. This cost-effective and fast molecular tool provides a valuable resource for characterization and selection programs of avocado cultivars genetically related to the West-Indian horticultural race.

Main conclusionSoil application of entomopathogenic nematodes enhanced the growth and modulated the aboveground defenses in potato plants, while interactions with mycorrhizal fungi shaped the volatile emissions and herbivory, underscoring the nematodes as primary drivers in multi-mutualistic systems.Plants frequently engage with multiple belowground mutualists simultaneously, yet the outcomes of such multi-partner associations for plant traits and herbivore resistance remain poorly understood. In this study, we investigated the independent and combined effects of arbuscular mycorrhizal fungi (AMF; Rhizophagus irregularis) and entomopathogenic nematodes (EPNs; Steinernema carpocapsae and Heterorhabditis bacteriophora) on the growth and defense phenotype of potato (Solanum tuberosum) plants. Using a fully factorial experimental design, we assessed the plant height, foliar phenolic content, constitutive volatile organic compound (VOC) emissions, and leaf damage by chewing herbivores. We found that EPNs alone enhanced plant height and reduced flavonoid concentrations, consistent with a potential shift in growth–defense allocation. AMF inoculation had no significant main effects on any measured trait but interacted with EPNs in a species-specific manner. Notably, mycorrhization increased VOC emission only in the presence of H. bacteriophora, while co-inoculation with AMF and S. carpocapsae significantly reduced herbivore damage—a response not observed in either single-symbiont treatment. These findings highlight the non-additive and context-dependent nature of belowground mutualist interactions, with distinct outcomes governed by the identity of the EPN. To our knowledge, this is among the first documented cases where aboveground herbivory is attenuated through a context-specific interaction between two root-associated mutualists. Overall, our results highlight the ecological significance of considering species-specific, multi-mutualist interactions in shaping plant traits and suggest that combining functionally distinct symbionts may offer a novel approach to enhancing crop resilience in sustainable agriculture.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00425-025-04877-w.

Abstract Arbuscular mycorrhizal fungi (AMF) influence plant establishment and nutrient balance, yet their role in insular endemics remains poorly understood. In this work, it was assessed field AM colonization and edaphic-foliar context in three Artemisia taxa from the Canary Islands ( A. thuscula Cav. and A. ramosa C. Sm. Ex Link. (endemic), and A. reptans C. Sm. (native, Vulnerable), and tested early mycorrhizal responsiveness of A. thuscula Cav. in nursery conditions after inoculation with Funneliformis mosseae (T.H. Nicolson & Gerd.), using A. annua L. as a reference. Field colonization varied strongly among sites: A. thuscula Cav. on the southern slope of Tenerife island showed the highest colonization (44%), linked to sandy, organic-rich soils, whereas northern and coastal populations had low values in finer, saline substrates. Foliar nutrients mirrored these contrasts, particularly for potassium, sodium and iron. In the nursery, AM inoculation enhanced seedling biomass (+ 93%) and foliar nitrogen and potassium, even though root colonization at lifting was low (3%), indicating strong responsiveness but weak dependence. These results identify A. thuscula Cav. as a facultatively mycotrophic endemic with high early responsiveness to AMF, supporting its integration into propagation and restoration of Macaronesian flora.

Tropical fruits have become increasingly popular due to their interesting nutritional composition. This rise in their consumption has resulted in more by-products generated during their production, processing, and commercialization. Papaya, for instance, is one of the leading tropical fruits produced globally due to its essential macro- and micronutrients for a healthy diet. On the other hand, dragon fruit, less known worldwide, is gaining popularity due to its nutrient and bioactive compound content. This review uses bibliometric analysis as a tool to investigate the scientific literature related to these two fruits, focusing specifically on their by-products. The objective is to identify the key authors and countries that are making substantial contributions to the research on these fruits and their by-products, such as peels and seeds. It will provide an overview of existing topics and highlight areas needing further investigation to enhance understanding and practical applications. This approach will help guide future research and innovations related to these fruits and their potential uses.

Reforestation with exotic species has often been used in arid and semiarid areas to restore degraded ecosystems. However, the effects of these plantations on soil biodiversity are still under debate. In the present study, we aimed to evaluate the long-term impacts (>60 years) of exotic plantations with Acacia cyclops and Pinus halepensis on soil biodiversity in an insular arid ecosystem of high ecological value. To do so, we study soil quality and soil arthropod communities in patches of vegetation under uniform edaphoclimatic conditions. Soil quality assessment was carried out by developing an ad-hoc Soil Quality Index (SQI) across seven sites, including two plantations ( Pinus or Acacia ), two degraded areas with a low cover of native species, and three sites with a high cover of native species. Whole organism community DNA (wocDNA) metabarcoding and barcoding were used to analyse key soil arthropod groups (Coleoptera, Acari and Collembola) recognized as habitat quality and biodiversity indicators. Our findings show that exotic plantations improved soil quality compared to degraded sites, with a considerable increase in the organic carbon pool, macronutrients and microbiological activity (SQI = 0.53 ± 0.12 vs. 0.29 ± 0.06). This improvement did not reach the values recorded in soils with a high cover of preserved native flora (SQI = 0.65 ± 0.12), with some exceptions. Richness of mesofauna and Coleoptera was lower in degraded areas (4.4 ± 1.6 and 0.4 ± 0.7, respectively) followed by exotic plantations (9.5 ± 2.6 and 1.2 ± 0.9) and permanent native vegetation (14.1 ± 5.5 and 2.2 ± 1.8). Soil quality significantly explained up to 52 % and 17 % of the variance in the richness of mesofauna and Coleoptera, respectively. While exotic plantations appear to prevent further land degradation in terms of soil quality, multivariate analysis shows that the structure of soil arthropod communities, particularly in Pinus plantations and to a lesser extent in Acacia plantations, differs significantly from that of soils in ecosystems with remnant native flora. These results highlight the need for a careful balance between biodiversity conservation and soil health management, especially in areas susceptible to desertification. • Soil fauna in exotic plantations is not as complex as in remnant native ecosystems. • Ad-hoc soil quality index correlates with richness of key invertebrate groups. • Exotic plantations create transitional states between native and degraded areas. • Introduced species incidence in exotic areas doubles that of native ecosystems.

Mangifera indica L. by-products obtained by three extraction methods from three cultivars (Keitt, Sensation and Gomera-3) were tested for their antibacterial properties against 20 bacterial species. These species were selected based on their relevance to winemaking processes (Acetobacter, Gluconobacter and Gluconacetobacter), fermented meat products (Staphylococcus) and human diseases (Pseudomonas, Escherichia, Shigella and Klebsiella). All mango by-product extracts showed antimicrobial activity in agar diffusion and broth microdilution experiments. However, differences in antimicrobial activity against acetic acid bacteria were detected between the peel extracts obtained from the two extraction processes. Furthermore, a wide range of minimum inhibitory concentration (MIC) data were found; Staphylococcus spp. (10 species) showed MICs between 1.0–240 mgGAE/mL and Acetobacter spp. (4 species) showed MICs between 1.7 and 200 mgGAE/mL. The most sensitive bacteria belonged to the staphylococcal species (MIC: 1 mgGAE/mL) and the most resistant was Gluconacetobacter saccharivorans (MIC > 400 mgGAE/mL). In general, there was no significant correlation between the phenolic compounds identified and the MIC values. The minimum bactericidal concentration (MBC) revealed that the mango extracts had a bacteriostatic effect. A simple and reliable method for the determination of MIC and MBC in microdilution assays with acetic acid bacteria was described. These results highlight the antibacterial properties of mango by-products against species associated with food spoilage microorganisms and human diseases.