Pecan Research Articles

Population trends of the Cape Parrot Poicephalus robustus in the Amatholes, Eastern Cape: trialling ground-based flock photography for demographic and health assessment

Globally, 60% of species in the order Psittaciformes are experiencing population declines. Understanding demographic and health trends in populations is vital for the prioritisation of limited conservation resources. The Cape Parrot Poicephalus robustus is a South African endemic forest species that is endangered by habitat degradation and Psittacine Beak and Feather Disease (PBFD). In the Amathole region of the Eastern Cape province, Cape Parrots gather in large numbers every autumn to feed at a particular orchard of Pecan trees Carya illinoinensis. This annual event is an opportunity for researchers to assess trends in a population that does not otherwise typically form large flocks. We used a novel, non-invasive method of flock photography analysis between 2017 and 2022 to assess the demographics and PBFD symptoms of the population. A mean of 439 ± SD 127 Cape Parrots visited the orchard on the peak day each year, with 1.2 males per female and 3 adults per juvenile overall. Proportions of juveniles fluctuated between extremes of 70% in 2019 and < 4% in 2020. PBFD symptoms increased markedly in the food-scarce year of 2019, with a gradual recovery seen in the years following. Roosting numbers were also tracked monthly from 2018 to 2022 to indicate local population fluctuations in the study area around Hogsback. An average of 112 ± SD 31 Cape Parrots roosted there, with roost counts notably higher from January to June, bolstered by newly-fledged juveniles prior to their dispersal. This study demonstrates the use of flock photographs as an effective, non-invasive tool to assess the demographics and health of an avian population.

Scab Intensity in Pecan Trees in Relation to Hedge-Pruning Methods.

Pecan is a valuable nut crop cultivated in the southeastern United States. Among the major yield-limiting factors in the region is scab, caused by the plant pathogenic fungus Venturia effusa. Managing scab in tall trees (15 to 25+ m) in pecan orchards is challenging because of the limitations of getting sufficient spray coverage throughout the canopy. We explored the effects of hedge pruning on scab in three orchards: 14-m-tall cv. Desirable trees winter hedge pruned on alternate sides to 11 m (site 1), 18-m-tall cv. Stuart trees hedge pruned on both sides simultaneously to 11 m (site 2), and 15-m-tall cv. Caddo trees winter hedge pruned in winter versus summer to 11 m (site 3). At site 1 and 2, hedge-pruned trees were compared with nonpruned control trees. All trees received recommended fungicide applications to control scab via an air-blast sprayer. Disease incidence and/or severity was assessed at different sample heights on shoots, foliage, and fruit during three seasons (2020, 2021, and 2022). At site 1 the hedge-pruned trees often had significantly or numerically more severe scab on foliage and fruit compared with the control trees, although the differences were mostly small. The frequency of mature fruit with scab severity <10% was greatest on control trees in 2021 and 2022. At site 2, there were few differences between hedge-pruned and control trees (on fruit, scab severity was either significantly less on hedge-pruned trees or not different from the control), but the frequency of mature fruit with scab severity <10% was consistently greatest on hedge-pruned trees. At site 3, scab intensity was low, and there were no significant differences in scab severity between winter- and summer-pruning treatments. At sites 1 and 2, there was generally more severe scab at greater sample heights compared with low in the canopy. At site 3 there was little effect of height on disease. The benefit of hedge pruning likely increases with tree height in scab-susceptible cultivars. If a tree is taller than ∼15 m, a greater proportion of the fruit will be within reach of efficacious spray coverage from air-blast sprayers.

Synthesis of a sustainable material based on pecan nutshell for the elimination of diclofenac in aqueous solution: Characterization and adsorption studies

In the present study, activated carbons were synthesized from pecan nutshells (Carya illinoinensis) using two physicochemical methods: steam (CAVA) and phosphoric acid (CAAF). Their capacity to remove diclofenac from aqueous solution, as well as their textural, morphological, and physicochemical properties, were evaluated. N2 physisorption analysis revealed the microporous nature of the carbons, with specific surface areas of 1123.5 and 375.6 m2 g−1 for CAAF and CAVA, respectively. Scanning electron microscopy showed a heterogeneous morphology, with evident roughness caused by the irregularity of the surfaces resulting from the activation method used. The point of zero charge was 2.9 for CAAF and 8.9 for CAVA. Surface charge distribution analysis indicated that the surface of CAAF is predominantly negative, while that of CAVA is predominantly positive, which reflects the difference in active sites between the two materials. Infrared spectroscopy allowed for the identification of the functional groups present on the surfaces of the materials generated by the activation methods. Thermogravimetric analysis demonstrated that CAAF is more hydrophilic than CAVA, and both carbons exhibited low ash content (7 % for CAVA and 6 % for CAAF). The maximum adsorption capacity for DCF was achieved at a pH of 7, with values of 49.0 mg g−1 for CAVA and 230.8 mg g−1 for CAAF, decreasing as the pH increased from 7 to 10. Increasing the solution temperature from 15 to 35 °C, the adsorption capacity of CAVA and CAAF increased 1.2 and 1.5 times, respectively. Adsorption increased by 1.7 times for CAVA and 1.2 times for CAAF when the ionic strength was raised with a NaCl concentration from 0.001 to 0.01 M. The proposed mechanism for diclofenac adsorption on CAVA involved electrostatic interactions (pH < pHPZC), whereas the predominant mechanism in CAAF was π-π interactions (pH > pHPZC).

Pecan (Carya illinoinensis (Wangenh.) K. Koch) nuts as an emerging source of protein: extraction, physicochemical and functional properties.

The increasing demand for sustainable alternatives to traditional protein sources, driven by population growth, underscores the importance of protein in a healthy diet. Pecan (Carya illinoinensis (Wangenh.) K. Koch) nuts are currently underutilized as plant-based proteins but hold great potential in the food industry. However, there is insufficient information available on pecan protein, particularly its protein fractions. This study aimed to explore the physicochemical and functional properties of protein isolate and the main protein fraction glutelin extracted from pecan nuts. The results revealed that glutelin (820.67 ± 69.42 g kg-1) had a higher crude protein content compared to the protein isolate (618.43 ± 27.35 g kg-1), while both proteins exhibited amino acid profiles sufficient for adult requirements. The isoelectric points of protein isolate and glutelin were determined to be pH 4.0 and pH 5.0, respectively. The denaturation temperature of the protein isolate (90.23 °C) was higher than that of glutelin (87.43 °C), indicating a more organized and stable conformation. This is further supported by the fact that the protein isolate had a more stable main secondary structure than glutelin. Both proteins demonstrated improved solubility, emulsifying, and foaming properties at pH levels deviating from their isoelectric points in U-shaped curves. Compared to the protein isolate, glutelin displayed superior water and oil absorption capacity along with enhanced gelling ability. The protein isolate and glutelin from pecan nuts exhibited improved stability and competitive functional properties, respectively. The appropriate utilization of these two proteins will support their potential as natural ingredients in various food systems. © 2024 Society of Chemical Industry.

Pecan-medicinal crops intercropping improved soil fertility and promoted interactions between soil microorganisms and metabolites

BackgroundPecan [Carya illinoinensis (Wangenh.) Koch] is a widely cultivated dried fruit and woody oil tree with high economic value. Continuous sole planting of pecan caused some land to lie idle and deterioration of soil conditions. Tree and medicinal crops intercropping represents an environmental-friendly and economically feasible solution to these issues. Thus, we aimed to explore the underlying mechanism by which intercropping improved soil condition by regulating the interactions of the soil microbiome and metabolome. In this study, pecans were intercropped with medicinal crops caper spurge and honeysuckle on a tree farm in China. A combined analysis of soil microbiomes and metabolomes was performed to discover the effects of intercropping on bulk and rhizosphere soils.ResultsThe results showed that intercropping improved the edaphic properties of bulk soil and promoted the growth of pecan and caper spurge. Intercropping also significantly altered the structures of both bacterial and fungal communities in bulk soil, stabilised the enrichment of nitrogen-cyclic bacteria, for instance, Bacillus, and decreased the relative abundances of plant–pathogenic fungi, for instance, Fusarium. In addition, the result of metabolomic analysis showed that intercropping promoted the synthesis of functional compounds, such as trehalose and ethanolamine, which enhanced plant disease resistance in bulk soils. Moreover, the co-occurrence networks of microbiomes and metabolomes of bulk soils revealed that Bacillus was significantly correlated with Fusarium, Alternaria, and trehalose under intercropping patterns. Furthermore, analysis of microbiomes and metabolomes in the rhizosphere soil of caper spurge and honeysuckle revealed that Penicillium and Rhizomicrobium were significantly increased by intercropping and showed more dynamic connections with other genera and metabolites compared with single planting.ConclusionsOverall, intercropping pecans with caper spurge and honeysuckle can improve soil conditions and promote plant growth through microbiological and metabolomics integrated analyses. This study provides valuable information and theoretical basis for optimizing land resource utilisation and improving soil conditions in tree fields like pecan fields via intercropping, thereby reducing production losses and ensuring economic benefits.Graphical

Metabolome and Transcriptome Analyses Reveal Metabolomic Variations and Key Transcription Factors Involved in Lipid Biosynthesis During Seed Development in Carya illinoinensis.

Plant oils are a large group of neutral lipids that play a vital role in the food and oleochemical industries. The pecan (Carya illinoinensis) is a promising woody oil crop known for its high-quality sources of essential fatty acids and various bioactive compounds that may aid in preventing heart diseases. However, there is still a lack of understanding regarding the accumulation of lipids and the molecular mechanism of lipid biosynthesis during seed development. This study aims to analyze the metabolite variations and molecular mechanisms of lipid biosynthesis by integrating untargeted metabolomics and transcriptomics during pecan seed development. A total of 293 differentially accumulated metabolites were identified and further categorized into 13 groups, with lipids and lipid-like molecules constituting the largest group. The oil content and fatty acid compositions of pecan embryos were assessed at three stages of seed development. Oleic acid (c18:1) and linoleic acid (c18:2n6) were found to be the most abundant unsaturated fatty acid components in pecan embryos. Additionally, a comprehensive analysis revealed 15,990 differentially expressed genes, with a focus on the key genes related to lipid metabolism. Furthermore, the study identified 1201 transcription factors from differentially expressed genes. These transcription factors were divided into 65 families, with different members in the same family exhibiting different expression patterns during seed development. The expression patterns of ten transcription factor genes during seed development were verified by qRT-PCR. Two key genes, CiABI3 and CiFUS3 were further cloned and found to be localized in the nucleus. This study used metabolome and transcriptome analysis during key periods of pecan seed development to identify the key genes associated with seed development and fatty acid biosynthesis.

The rootstock genotype shapes the diversity of pecan (Carya illinoinensis) rhizosphere microbial community.

Pecans (Carya illinoinensis), one of the most valuable native North American nut crops, are commonly propagated through grafting to preserve the desired characteristics from parent trees. Since successful cultivation of pecan trees relies on the interplay among scion varieties, rootstocks, and soil conditions, this study investigated the microbial change to communities in the soils and roots of southern (87MX5-1.7) and northern (Peruque) rootstocks in a rootstock test orchard. Both grafted with the 'Pawnee' scion cultivar. Bacterial 16S ribosomal RNA and fungal ITS were amplified from both roots and rhizosphere soils of the two 10-year-grafted trees, then sequenced and annotated into trophic and nutrient-related groups to characterize the rhizosphere microbiota. The Peruque roots had a higher relative abundance of saprotroph fungi, while 87MX5-1.7 exhibited higher levels of symbiotroph fungi and nitrogen fixation-related bacteria. Among them, the presence of symbiotroph fungi, particularly ectomycorrhizal fungi, notably differed between these two rootstocks, with a significantly higher presence observed in the root of 87MX5-1.7 compared to Peruque. This variation likely leads to divergent pathways of nutrient translocation: Peruque was in favor of multiple fungi (Russula and Inocybe) to gain nutrition, while 87MX5-1.7 preferred a specific domain of fungi (Tuber) and nitrogen fixation-related bacteria (Bradyrhizobia) to form beneficial symbiosis. Moreover, the presence of pathogens suggested a potential risk of Fusarium patch and snow molds in 87MX5-1.7, while canker and black foot disease pose threats in Peruque. The findings of this study suggest that rootstocks from different origins shape rhizosphere microbes differently, potentially affecting nutrient uptake and nut yield. Exploring rootstock-microbe combinations could provide insights into optimizing scion growth and ultimately increasing nut yield. By understanding how different rootstock-microbe interactions influence pecan tree development, growers can strategically select combinations that promote beneficial symbiotic relationships, enhancing nutrient uptake, disease resistance, and overall tree vigor.

An emulsion extraction system composed of hydrophobic deep eutectic solvent and water for synchronous extraction of oil and phenolic compounds from U.S. pecans [Carya illinoinensis (Wangenh.) K. Koch]

U.S. pecans nuts are rich in oils and phenolic compounds with important biological functions. At present, the reports about simultaneous extraction of oil and phenolic compounds are limited, and the traditional procedure is complicated and the yield is low. In this study, a new emulsion formed by hydrophobic deep eutectic solvent (DES) and water was used as extractant for synchronous extraction of oil and phenolic components from U.S. pecans, and subsequently the two were recovered from the upper and lower phases based on the incompatibility of DES and water, respectively. The oil and phenolic compounds obtained by the optimization of extraction conditions were 615.29 mg/g and 82.11 mg/g, respectively, which were higher than those obtained by conventional methods. At the same time, the extraction mechanism is discussed through the extraction kinetics and thermodynamics. The extraction process conformed to the Fick’s second law, and it was an endothermic process. After directional recovery by macroporous resin and back-extraction, the effectiveness of the method was proved by the analysis of fatty acid composition of oil, spectral characterization of phenolic compounds and antioxidant activities.

Comparative analysis of aroma profiles in walnut, pecan and hickory nuts during the roasting process using E-nose, HS-SPME-GC-MS, and HS-GC-IMS

Walnut, pecan, and hickory nuts are well known for their nutritional value and health benefits, with consumption having increased significantly in recent years. Outstanding aroma is an important indicator for nut quality evaluation. However, the impacts of thermal processing on their aroma formation are not well understood. To address this gap, a comprehensive analysis of the aroma profiles were conducted during the roasting process using both sensory evaluation and advanced analytical equipment, including an electronic nose (E-nose), headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), and headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). The results indicated that thermal processing had a substantial effect on the sensorial characteristics of the nuts, with hickory nuts exhibiting a distinct nutty aroma compared to walnuts. HS-SPME-GC-MS analysis further identified 118 volatile organic compounds (VOCs), encompassing 33 heterocyclic compounds, 18 aldehydes, 11 aromatics, 18 ketones, and other compounds, while HS-GC-IMS analysis detected 63 volatile compounds. Notably, the roasting process led to the reduction in alcohols and acids, while simultaneously caused the increase of esters, ketones, pyrazines, and phenols, all of which are crucial for the development of nut aroma. Especially, some components like 1-Octanol, 2-Pentyl-furan, Hexanal, Acetylpyrazine, Benzophenone, and Octyl ester may contribute to unique odors of pecan and hickory nuts. These findings provide valuable insights into the flavor formation of the three nuts and the optimization of roasting process.

The Integrated Analysis of miRNome and Degradome Sequencing Reveals the Regulatory Mechanisms of Seed Development and Oil Biosynthesis in Pecan (Carya illinoinensis).

Pecan seed oil is a valuable source of essential fatty acids and various bioactive compounds; however, the functions of microRNAs and their targets in oil biosynthesis during seed development are still unknown. Here, we found that the oil content increased rapidly in the three early stages in three cultivars, and that oleic acid was the predominant fatty acid component in the mature pecan embryos. We identified, analyzed, and validated the expression levels of miRNAs related to seed development and oil biosynthesis, as well as their potential target genes, using small RNA sequencing data from three stages (120, 135, and 150 days after flowering). During the seed development process, 365 known and 321 novel miRNAs were discovered. In total, 91 known and 181 novel miRNAs were found to be differentially expressed, and 633 target genes were further investigated. The expression trend analysis revealed that the 91 known miRNAs were classified into eight groups, approximately two-thirds of which were up-regulated, whereas most novel miRNAs were down-regulated. The qRT-PCR and degradome sequencing data were used to identify five miRNA- target pairs. Overall, our study provides valuable insights into the molecular regulation of oil biosynthesis in pecan seeds.

Carya Illinoinensis-mediated Green Synthesis and Antimicrobial Screening of Zirconium Oxide Nanoparticles: The Promising Antimicrobial Agent

Background: The synthesis of metal-based nanoparticles through conventional methods involves harsh conditions, high costs, and severe environmental threats. To overcome these issues, researchers are nowadays focusing on eco-friendly and low-cost methods for the synthesis of nanoparticles. Finally, several plant-mediated synthesis techniques have been developed, which have various advantages, such as low-cost, environmentally friendly, and easy application. The plant extract not only serves as a reducing agent but also plays a role as a stabilizing agent. The plantmediated synthesis provides new opportunities for cost-effective, environmentally-friendly nanoparticle synthesis with high dispersity and stability. Besides, bio-generated nanoparticles derived from plant extract have promising pharmacological applications, making them potential candidates for future medicines. Aims and Objectives: The current study aimed to synthesize zirconium oxide nanoparticles using Carya illinoinensis extract and examine their physicochemical properties. Additionally, the antimicrobial efficacy of these nanoparticles was evaluated against various pathogens, exploring their potential as potent antimicrobial agents. Method: The synthesized nanoparticles were analyzed and characterized by various techniques like UV-Vis spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Energy Dispersive X-ray spectroscopy (EDX). The UV-visible peak at 216 nm confirmed the formation of ZrO2 nanoparticles. The SEM images clearly showed that nanoparticles were spherical and relatively dispersed, with few agglomerations. The EDX spectra confirmed the existence of zirconium and oxygen as the basic constituents of the sample. TEM images demonstrated nanoparticles as spherical and uniformly dispersed but agglomerated with increasing precursor concentrations and decreasing nanoparticle dispersion. Fluconazole and gentamicin were used as standards in determining the antibacterial and antifungal activities of nanoparticles. Results: Considering the antifungal activity, a maximum zone of inhibition of 16 μg/ml was demonstrated in the case of 2 mM as compared to 4 mM and 6 mM concentrations. The Carya illinoinensismediated ZrO2 nanoparticles were screened against Gram-positive (S. aureus and P. aeruginosa) and Gram-negative (S. typhi and E. coli) bacterial strains. The fabricated nanoparticles exhibited promising action against all microorganisms. Conclusion: In the current study, zirconium oxide nanoparticles were synthesized by using Carya illinoinensis leaves extract as a reducing agent. The antifungal and antibacterial potential of the synthesized nanoparticles were evaluated. The green synthesis method used in this study is preferable to the others as it is more affordable, environmentally benign, and widely accessible.

Analyzing Solar Pyrolysis Process of Walnut Shells: Thermal Biomaterial Behavioral Outcomes

This paper presents a new experimental method for the thermal analysis of solar pyrolysis of walnut shells. The method consists of two types of thermal experiments: (A) the pyrolysis of walnut shells, and (B) the heating-cooling of the biochar obtained during experiment A. Nutshells are a waste product from the pecan nut industry. The state of Sonora, Mexico, produces large volumes of walnuts and their residue. Likewise, this region has a considerable solar resource. The motivation of this study is to obtain biochar - a bi-product of high commercial value used for soil enhancement - using solar energy and agro-industrial waste. In this experiment, biomass pyrolysis of 50g of nutshells was carried out inside a stainless-steel reactor heated with concentrated radiation from a solar simulator. Three different heat fluxes were used: 234, 482, and 725 W. The maximum reaction temperatures were: 382, 498, and 674 °C respectively. The composition of the pyrolysis gases (H2, CO, CO2, and CH4) was measured and the biochar obtained was characterized. Finally, the performance of the solar reactor allowed us to identify and differentiate between evaporation, pyrolysis of cellulosic material, and lignin degradation

Phenotypic diversity and population structure of Pecan (Carya illinoinensis) collections reveals geographic patterns

Pecan (Carya illinoinensis) is an economically important nut crop known for its genetic diversity and adaptability to various climates. Understanding the growth variability, phenological traits, and population structure of pecan populations is crucial for breeding programs and conservation. In this study, plant growth and phenological traits were evaluated over three consecutive seasons (2015–2017) for 550 genotypes from 26 provenances. Significant variations in plant height, stem diameter, and budbreak were observed among provenances, with Southern provenances exhibiting faster growth and earlier budbreak compared to Northern provenances. Population structure analysis using SNP markers revealed eight distinct subpopulations, reflecting genetic differentiation among provenances. Notably, Southern Mexico collections formed two separate clusters, while Western collections, such as 'Allen 3', 'Allen 4', and 'Riverside', were distinguished from others. 'Burkett' and 'Apache' were grouped together due to their shared maternal parentage. Principal component analysis and phylogenetic tree analysis further supported subpopulation differentiation. Genetic differentiation among the 26 populations was evident, with six clusters highly in agreement with the subpopulations identified by STRUCTURE and fastSTRUCTURE. Principal components analysis (PCA) revealed distinct groups, corresponding to subpopulations identified by genetic analysis. Discriminant analysis of PCA (DAPC) based on provenance origin further supported the genetic structure, with clear separation of provenances into distinct clusters. These findings provide valuable insights into the genetic diversity and growth patterns of pecan populations. Understanding the genetic basis of phenological traits and population structure is essential for selecting superior cultivars adapted to diverse environments. The identified subpopulations can guide breeding efforts to develop resilient rootstocks and contribute to the sustainable management of pecan genetic resources. Overall, this study enhances our understanding of pecan genetic diversity and informs conservation and breeding strategies for the long-term viability of pecan cultivation.

Rapidly Self-Healable and Melt-Extrudable Polyethylene Reprocessable Network Enabled with Dialkylamino Disulfide Dynamic Chemistry.

Catalyst-free, radical-based reactive processing is used to transform low-density polyethylene (LDPE) into polyethylene covalent adaptable networks (PE CANs) using a dialkylamino disulfide crosslinker, BiTEMPS methacrylate (BTMA). Two versions of BTMA are used, BTMA-S2, with nearly exclusively disulfide bridges, and BTMA-Sn, with a mixture of oligosulfide bridges, to produce S2 PE CAN and Sn PE CAN, respectively. The two PE CANs exhibit identical crosslink densities, but the S2 PE CAN manifests faster stress relaxation, with average relaxation times ∼4.5 times shorter than those of Sn PE CAN over a 130 to 160°C temperature range. The more rapid dynamics of the S2 PE CAN translate into a shorter compression-molding reprocessing time at 160°C of only 5min (vs 30min for the Sn PE CAN) to achieve full recovery of crosslink density. Both PE CANs are melt-extrudable and exhibit full recovery within experimental uncertainty of crosslink density after extrusion. Both PE CANs are self-healable, with a crack fully repaired and the original tensile properties restored after 30min for the S2 PE CAN or 60min for the Sn PE CAN at a temperature slightly above the LDPE melting point and without the assistance of external forces.

Two Carya Species, Carya hunanensis and Carya illinoinensis, Used as Rootstocks Point to Improvements in the Heat Resistance of Carya cathayensis.

Grafting as a crucial horticultural technique has been widely used in the cultivation of Carya cathayensis (Chinese hickory), which is a unique and important economic tree in the northeast of Zhejiang Province and the south of Anhui Province. However, the existing literature lacks research on the potential impact of various rootstocks on the thermal tolerance of Chinese hickory. The objectives of this study were to evaluate heat tolerance in four distinct groups of Chinese hickory, including C. cathayensis grafted onto Carya hunanensis and Carya illinoinensis, one self-grafted group (C. cathayensis grafted onto C. cathayensis), and one non-grafted group (C. cathayensis). We examined photosynthesis parameters, phytohormones, and differentially expressed genes in the four various hickory groups subjected to 25 °C, 35 °C, and 40 °C heat stress (HS). The results demonstrated that grafting onto C. hunanensis and C. illinoinensis exhibited a higher net photosynthetic rate and stomatal conductance, lower intercellular CO2 concentration, and smaller changes in plant hormone content compared to self-grafted and non-grafted group under HS. The transcriptome results revealed that the majority of differentially expressed genes (DEGs) associated with photosynthetic pathways exhibited downregulation under HS, while the degree of variation in grafted groups using C. hunanensis and C. illinoinensis as rootstocks was comparatively lower than that observed in self-grafted and non-grafted groups. The alteration in the expression patterns of DEGs involved in plant hormone synthesis and metabolism under HS corresponded to changes in plant hormone contents. Overall, Chinese hickory grafted onto C. hunanensis and C. illinoinensis exhibited enhanced resistance to high-temperature stress at the juvenile stage.

Foliar applications of zinc oxide nanoparticles and boric acid affect leaf oxidative metabolism and productivity in young pecan trees

Zinc and boron are nutrients that often suffer low bioavailability to pecan trees grown in calcareous soils whereas adequate supplies of these two elements is essential for commercial pecan production. Working with young pecan trees, we evaluated changes in oxidative metabolism, levels of bioactive compounds, yield components and foliar nutrient concentrations in response to foliar sprays (50 or 100 mg L−1) of zinc oxide nanoparticles (ZnO NPs) and boron (H3BO3). Four different treatment solutions were applied in a completely randomised design with six replications per treatment (24 trees in total). Zinc and B treatments were applied before pistil receptivity (3 weeks before anthesis) and at stem elongation stage 31, 39/60; flowering stage 69; fruit stages 7–75 and continued for a total of five applications at 14-day intervals. We evaluated enzyme activities (SOD, H2O2, CAT and GPx), AC, phenols, flavonoids, leaf area, chlorophyll, total anthocyanins and nut yield and quality (nut weight and % kernel). The mineral concentrations in the leaflets were also determined. The mineral concentrations (N, P, K, Ca, Mg, Fe, Cu, Mn, Ni, Zn and B) in the leaflets were also determined. Spraying ZnO NPs and B increased SOD activity, CA, chlorophyll concentration, mineral nutrients (N, K, Ca, Zn and B) and yield. However, reductions were observed for CAT activity, nut quality and concentrations of phenol, flavonoid, anthocyanin and Fe. Boron increased GPx activity and P concentration. These results demonstrate that spraying low doses (50 mg L−1) of ZnO NPs and B can help reduce oxidative stress and increase yield, nut quality and leaf concentrations of Zn and B in young cv. Wichita pecan trees established on a calcareous soil.

ACTION OF Trichoderma asperellum AND BIOACTIVE METABOLITES ON Fusarium spp., PATHOGENS OF Carya illinoinensis

The cultivation of pecan tree [Carya illinoinensis (Wangenh.) K. Koch.] is expanding in Rio Grande do Sul state and, with that, there has been an increase in the disease reports. Among the diseases identified, there is a root rot caused by Fusarium spp. The control of phytopathogenic fungi present in the soil is difficult to obtain, and the control through antagonists such as Trichoderma spp. is a viable way of management. Thus, the objective of this work was to analyze different forms of action of Trichoderma asperellum in the control of Fusarium spp. The antagonistic action was evaluated by paring cultures, presence of volatile and non-volatile metabolites. The mycelial growth inhibition in the culture pairing ranged from 10.38% to 43.17%, while for volatile metabolites protection was lower, reaching values of a maximum of 14.54%. As for the non-volatile metabolites, a percentage of inhibition varied from zero for some treatments to 44.99% in the control of Fusarium graminearum. T. asperellum inhibited the growth of Fusarium spp. through different studied modes of action.

Ascorbic acid-enriched cactus mucilage coatings maintained quality attributes of roasted ‘Wichita’ pecan nuts under accelerated storage conditions

The potential of a cactus mucilage (CM)-based edible coating enriched with ascorbic acid (AA) for preserving microwave-roasted pecan nuts’ quality during accelerated storage was investigated. CM (3 %) was mixed with different concentrations of AA, which were 0.03, 0.015, and 0.09 %, to formulate edible coating solutions that were applied to microwave-roasted (700 W, 2.27 min) pecan nuts before accelerated storage for 25 days at 60 °C. Samples were taken at a 5-day interval to be analysed for colour properties (L = lightness, BI = browning index, and TCD = total colour difference), hardness, total yeast and mold, total flavonoids content (TFC), total phenolic content (TPC), ferric reducing antioxidant power (FRAP), DPPH radical scavenging activity, peroxidase (POD), and polyphenol oxidase (PPO) enzyme activities. Coating microwave-roasted pecan nuts with 3 % CM enriched with AA at low concentrations such as 0.015 % proved effective in preserving the colour, hardness, TPC, TFC, FRAP, and reducing the activities of POD and PPO enzymes. This study has demonstrated that CM enriched with AA edible coatings has the capacity to protect the quality and prolong the shelf-life of microwave-roasted pecan nuts.

Determination of Energy Use Efficiency and Greenhouse Gas (GHG) Emissions of Pecan (Carya illinoiensis) Production in Türkiye

Determination of Energy Use Efficiency and Greenhouse Gas (GHG) Emissions of Pecan (Carya illinoiensis) Production in Türkiye

First Report of Anthracnose Caused by Colletotrichum plurivorum on Passion fruit in Guangxi, China.

Passion fruit (Passiflora edulis Sims.) is popular for its rich taste and nutritional value. The planting area of passion fruit in Guangxi has reached 24,300 ha, with an annual output of 380,000 t (Qian 2023). In March 2023, leave spots on more than half of the plants (cv. Qinmi "NO.9"). Moreover, the incidence of disease on the leaves was approximately 20% in Shabu Town, Qinnan District, Qinzhou City, Guangxi, China (N20˚54'-22˚41', E107˚27'-109˚56'). Leaf diseases were orbicular or irregular in shape, white, whitish-grey, yellowish, or gray in color. When leaves were severely affected, larger blotches were formed with yellow halos. For pathogen isolation, three diseased leaf samples were collected from three gardens, respectively, and 5×5 mm tissues were cut from infected margins, surface-disinfected in 75% ethanol for 15 s, followed by 2% sodium hypochlorite for 1 min, rinsed three times with sterile water, and incubated on PDA at 25°C under 12/12 h light/darkness. After 5 days, ninety cultures were isolated, sixty isolates with similar morphology were retained, and three representative isolates BY-1, BY-2, and BY-4 were randomly selected for further study. On PDA, colonies of the three isolates displayed white or grayish-white. Conidia were single-celled, hyaline, and cylindrical, measuring 17.3±1.5 × 6.3±0.7 μm, 17.8±1.7 × 6.0±0.6 μm, and 16.3±1.4 × 6.4±0.6 μm (n=90) for BY-1, BY-2, and BY-4, respectively. Appressoria were single, brown or black, and irregular in shape, measuring 10.2±1.1×6.5±0.5 μm, 10.5±1.3×7.3±0.6, and 10.9±0.8×7.0±0.8 (n=90) for BY-1, BY-2, and BY-4, respectively. These morphological characteristics were similar to Colletotrichum spp. as previously described (Damm et al. 2019). The isolates were further identified by sequencing the internal transcribed spacer (ITS-ITS1/ITS4), glyceraldehyde-3-phosphate dehydrogenase (GAPDH-GDF/GDR), actin (ACT-512F/783R), partial sequences of the chitin synthase 1 (CHS-1-79F/354R), and beta-tubulin 2 (TUB2-T1/Bt2b) (Zhang et al. 2023). All sequences were deposited in GenBank (ITS: OR741759 to OR741761, GAPDH: OR767654 to OR767656, ACT: OR767657 to OR767659, CHS-1: OR767660 to OR767662, TUB2: OR767651 to OR767653). A phylogenetic tree was built with RAxML version 8.2.10 based on concatenated sequences of ITS-GAPDH-ACT-CHS-1-TUB2. The results revealed that the three isolates clustered with C. plurivorum. To confirm the pathogenicity of the three isolates, attached leaves of healthy 5-month-old passion fruit plants were injured in the middle region with sterile toothpicks and inoculated with 20 μL of spore suspension (106 conidia/mL), and the noninoculated control received 0.05% Tween-20 (6 leaves/plant, 3 plants/treatment). The inoculated plants were kept in a greenhouse at 25°C and covered with plastic bags to maintain high humidity. After 9 days, all inoculated leaves were symptomatic, whereas no symptoms were observed in the control. C. plurivorum was reisolated from infected leaves, confirming Koch's postulates. C. plurivorum has been reported to infect Abelmoschus esculentus (Batista et al. 2020) and Carya illinoinensis in China (Zhang et al. 2023). However, this is the first report of anthracnose caused by C. plurivorum on passion fruit in China. The results can provide a robust basis for scientific prevention and control of anthracnose.