Progression of Kernel Mold on Hazelnut
Hazelnut kernel mold, caused by a number of fungal species, has been a chronic problem in Pacific Northwest hazelnut production areas for many years. Two highly susceptible breeding selections and two commercial cultivars were used to investigate kernel mold development over time and possible correlations with rainfall. Nuts were allowed to naturally fall onto orchard soil, regularly collected, cracked open, and evaluated for kernel mold. Disease progress for each selection or cultivar was evaluated each year with both linear and exponential models. The general progression of kernel mold was similar for the two breeding selections and cultivars Ennis and Lewis, where kernel mold increased slowly during the nut dropping period but more rapidly after normal harvest. An exponential model described disease progress better than a linear model for 8 of the 10 significant disease progress curves examined. Although some years had significantly higher estimated rates of disease increase, this parameter was inversely related to the area under the disease progress curve (AUDPC). The incidence of kernel mold did not significantly increase over time for 8 of the 18 disease progress curves examined, including 6 of 8 curves for commercial cultivars. The relationship between initial kernel mold incidence and AUDPC was described well with a simple linear model indicating that initial disease incidence appeared to be a good predictor of AUDPC. The longer nuts remained on the ground, especially after harvest, the higher the incidence of kernel mold. Kernel mold incidence was not significantly correlated with rainfall totals for any period of time from flowering to harvest. Multiple harvests ending shortly after all nuts have fallen should result in lower incidence of kernel mold for growers.
Effects of Living Cover on the Soil Microbial Communities and Ecosystem Functions of Hazelnut Orchards
Living cover is an important management measure for orchards in China, and has certain influences on soil properties, microorganisms, and the micro-ecological environment. However, there are few studies on the effects of living cover on the soil changes in hazelnut orchards. In this study, we compared the soils of living cover treatments with Vulpia myuros and the soils of no cover treatments, and analyzed the observed changes in soil properties, microorganisms, and microbial functions by using high-throughput ITS rDNA and 16S rRNA gene Illumina sequencing. The results demonstrated that the total organic carbon content in the 20-40 cm deep soils under the living cover treatments increased by 32.87 and 14.82% in May and July, respectively, compared with those under the no cover treatments. The living cover treatment with V. myuros also significantly increased the contents of total phosphorus (TP), total nitrogen (TN), available phosphorus (AP), and available potassium (AK) in the soil samples. Moreover, the influence of seasons was not as significant as that of soil depth. The living cover treatment also significantly improved the soil enzyme activity levels. The results demonstrated that Ascomycota, Mortierellomycota and Basidiomycota were the dominant fungal phyla in all samples, while Proteobacteria, Actinobacteria, Acidobacteria, Firmicutes, and Chloroflexi were the dominant bacterial phyla, but the different treatments impacted the compositions of fungal and bacterial communities. Principal component analysis (PCA) showed that living cover with V. myuros significantly changed the soil fungal community structures whereas the bacterial community structures may be more sensitive to seasonal changes. At the microbial functional level, the living cover treatment increased the fungal operational taxonomic units (OTUs) of symbiotrophs and decreased that of pathotrophs. According to this study, we believe that the application of a living cover with V. myuros has a favorable regulating influence on soil properties, microbial communities and microbial function. This treatment can also reduce the use of herbicides, reduce the cost of orchard management, and store more carbon underground to achieve sustainable intensification of production in hazelnut orchards, so it can be considered as a management measure for hazelnut orchards.
https://doi.org/10.3389/fpls.2021.652493
History and Current Status of Phytoplasma Diseases in the Middle East
Phytoplasmas that are associated with fruit crops, vegetables, cereal and oilseed crops, trees, ornamental, and weeds are increasing at an alarming rate in the Middle East. Up to now, fourteen 16Sr groups of phytoplasma have been identified in association with more than 164 plant species in this region. Peanut witches' broom phytoplasma strains (16SrII) are the prevalent group, especially in the south of Iran and Gulf states, and have been found to be associated with 81 host plant species. In addition, phytoplasmas belonging to the 16SrVI, 16SrIX, and 16SrXII groups have been frequently reported from a wide range of crops. On the other hand, phytoplasmas belonging to 16SrIV, 16SrV, 16SrX, 16SrXI, 16SrXIV, and 16SrXXIX groups have limited geographical distribution and host range. Twenty-two insect vectors have been reported as putative phytoplasma vectors in the Middle East, of which Orosius albicinctus can transmit diverse phytoplasma strains. Almond witches' broom, tomato big bud, lime witches' broom, and alfalfa witches' broom are known as the most destructive diseases. The review summarizes phytoplasma diseases in the Middle East, with specific emphasis on the occurrence, host range, and transmission of the most common phytoplasma groups.
https://doi.org/10.3390/biology10030226
The Irrigation Effect on Nuts' Growth and Yield of Carya Illinoinensis
Pecan trees require adequate soil moisture conditions to produce nuts with good yield and quality. Irrigation should be an important considered practice in orchards management plan, mainly in regions with water deficit periods. The objective of this research was to evaluate irrigation on pecan nuts growth and yield. This study was conducted in Uruguay, during the fast development phase until the pecan nuts harvest. Three irrigation treatments were used: 0 L (control), 70 L and 140 L plant-1 of water every two days, applied via drip irrigation in seven-year-old pecan trees of the cultivar Success. The number of nuts per cluster and nuts' diameter and length were evaluated during nut growth. After harvesting, peeled nuts' width and length were measured, and after peeling, the kernel length, width, height and filling and the kernel and peel percentage were evaluated. According to the results, it was possible to identify that periods of water deficit during pecan nuts development affected the kernel filling stageand size. Irrigation in pecan plants provides greater dimensions and nuts mass. With the use of 140 L plant-1, there was an increase in the nut mass of more than 100% in relation to the nuts from plants without irrigation.
https://doi.org/10.1590/0001-3765202120181351
Characterization of Groundnut (Arachis hypogaea L.) Test Locations Using Representative Testing Environments With Farmer-Preferred Traits
In this study, the differential rankings of 36 groundnut genotypes under varying environmental conditions were studied at various levels of phenotype. Locations that are generally accepted by the crop- and soil-based research community to represent the entire Guinea and Sudan Savanna agro-ecological zones in Ghana were characterized, this time using a crop. The characterization was done based on four farmer-preferred traits (early and late leaf spot disease ratings, and haulm and pod yields) using three models (i.e., AMMI, GGE, and Finlay-Wilkinson regression). These models were used to capture specific levels of phenotype, namely, genotype-by-environment interaction (GE), genotype main effect plus GE (G+GE), and environment and genotype main effects plus GE (E+G+GE), respectively. The effect of three major environmental covariables was also determined using factorial regression. Location main effect was found to be highly significant (p < 0.001), confirming its importance in cultivar placement. However, unlike genotypes where the best is usually adjudged through statistical ranking, locations are judged against a benchmark, particularly when phenotyping for disease severity. It was also found that the locations represent one complex mega-environment, justifying the need to test new technologies, including genotypes in all of them before they can be approved for adoption nationally. Again, depending on the phenotypic level considered, genotypic rankings may change, causing environmental groupings to change. For instance, all locations clustered to form one group in 2017 for early and late leaf spot diseases and pod yield when GE was considered, but the groupings changed when G+GE was considered for the same traits in the same year. As a result, assessing genotypic performance at the various levels to arrive at a consensus decision is suggested. Genotypes ICGV-IS 141120 and ICGV-IS 13937 were found to be the best performing.
https://doi.org/10.3389/fpls.2021.637860
A 28-day repeated oral dose toxicity study of enniatin complex in mice
Enniatins are so-called "emerging mycotoxins" that commonly occur in milligrams per kilogram levels in grains and their derived products, as well as in fish, dried fruits, nuts, spices, cocoa, and coffee. The present study investigated the 28-day repeated oral dose toxicity of enniatin complex in CD1(ICR) mice. Enniatin B, enniatin B1, and enniatin A1 at a ratio of 4:4:1 were administered to male and female mice at doses of 0 (vehicle controls), 0.8, 4, and 20 mg/kg body weight/day. In life parameters did not change during the study period, with the exception of slight reductions in food consumption in male mice administered 4 and 20 mg/kg and in female mice administered 20 mg/kg. Body and organ weights did not change, and no alterations in hematology, blood biochemistry, or histopathology parameters were observed at the end of the administration period. Thus, we determined that the no-observed-adverse-effect level of enniatin complex was 20 mg/kg/day for both sexes under the present experimental conditions.
https://doi.org/10.2131/jts.46.157
Effect of cereal products supplementation with american blueberries, cranberries and cinnamon on the formation of type A and B trichothecenes group
Introduction: Mycotoxins - secondary mould metabolites with undesirable effects for humans - are common in the environment. These toxins are mainly produced by fungi of the genera Penicilium, Aspergillus and Fusarium.
Objective: The aim of this study was to evaluate the applicability of various sources of antioxidants (blueberries lyophilisate, cranberries lyophilisate and cinnamon powder), at 5 different concentrations (3%, 5%, 10%, 20%, 30%), to inhibit the formation of mycotoxins during the storage of cereal products. Analysed cereal samples included selected cereal grains, bran and cereal products intended for consumption by children.
Results: The results showed that supplementation of oat brans with the highest concentrations of blueberry lyophilisate resulted in a significant decrease in the mycotoxins levels; specifically: 20% concentration reduced the level of HT-2 toxin by 10.7% in one sample, while 30% concentration reduced it by 9.4% and 17.4% in 2 other samples. A similar result was measured for oat bran samples supplemented with the cranberry lyophilisate: specifically, 20% concentration significantly reduced the level of HT-2 toxin by 10.6% in one sample, while 30% concentration reduced it by an average of 18.0% ± 6,0% in 5 other samples. Finally, cinnamon powder supplementation caused a significant reduction in HT-2 levels in all stored samples, even at its lowest concentration. 30% supplementation resulted in HT-2 reduction in cereal samples by 67.1% - 76.1%, in wheat bran samples by 57.5% - 69.2%, in oat bran samples by 83.4% - 87.0% and by 55.0% - 100% in samples of cereal products intended for consumption by children.
Conclusions: Natural products used in the experiment (blueberry, cranberry, cinnamon) inhibited the formation of mycotoxins from the group of trichothecenes.
https://doi.org/10.26444/aaem/116903
A Recent Overview of Producers and Important Dietary Sources of Aflatoxins
Aflatoxins (AFs) are some of the most agriculturally important and harmful mycotoxins. At least 20 AFs have been identified to this date. Aflatoxin B1 (AFB1), the most potent fungal toxin, can cause toxicity in many species, including humans. AFs are produced by 22 species of Aspergillus section Flavi, 4 species of A. section Nidulantes, and 2 species of A. section Ochraceorosei. The most important and well-known AF-producing species of section Flavi are Aspergillus flavus, A. parasiticus, and A. nomius. AFs contaminate a wide range of crops (mainly groundnuts, pistachio nuts, dried figs, hazelnuts, spices, almonds, rice, melon seeds, Brazil nuts, and maize). Foods of animal origin (milk and animal tissues) are less likely contributors to human AF exposure. Despite the efforts to mitigate the AF concentrations in foods, and thus enhance food safety, AFs continue to be present, even at high levels. AFs thus remain a current and continuously pressing problem in the world.
https://doi.org/10.3390/toxins13030186
Improved de novo chromosome-level genome assembly of the vulnerable walnut tree Juglans mandshurica reveals gene family evolution and possible genome basis of resistance to lesion nematode
Manchurian walnut (Juglans mandshurica Maxim.) is a synonym of J. cathayensis, a diploid, vulnerable, temperate deciduous tree valued for its wood and nut. It is also valued as a rootstock for Juglans regia because of its reported tolerance of lesion nematode. Reference genomes are available for several Juglans species, our goal was to produce a de novo, chromosome-level assembly of the J. mandshurica genome. Here, we reported an improved assembly of J. mandshurica with a contig N50 size of 6.49 Mb and a scaffold N50 size of 36.1 Mb. The total genome size was 548 Mb encoding 29,032 protein coding genes which were annotated. The collinearity analysis showed that J. mandshurica and J. regia originated from a common ancestor, with both species undergoing two WGD events. A genomic comparison showed that J. mandshurica was missing 1,657 genes found in J. regia, and J. mandshurica includes 2,827 genes not found in of the J. regia genome. The J. mandshurica contained 1,440 unique paralogs that were highly enriched for flavonoid biosynthesis, phenylpropanoid biosynthesis, and plant-pathogen interaction. Four gene families related to disease resistance notable contraction (rapidly evolving) (LEA, WAK, PPR, and PR) in J. mandshurica compared to eight species. JmaPR10 and JmaPR8 contained 3 orthologous gene pairs with J. regia that were highly expressed in root bark. JmaPR10 is a strong candidate gene for lesion nematodes resistance in J. mandshurica. This J. mandshurica genome should be a useful resource for study of the evolution, breeding, and genetic variation in walnuts (Juglans).
https://doi.org/10.1111/1755-0998.13394
Identification of the promising Persian walnut (Juglans regia L.) genotypes among seedling-originated trees
Considerable genetic diversity among the native populations of Persian walnut (Juglans regia L.) provides a great opportunity to identify genotypes with valuable traits. In the present study, morphological and pomological diversity assessments of 362 walnut seedling origin genotypes were performed to identify superior genotypes. Significant differences were observed among the genotypes investigated in terms of the evaluated characters. Nut weighted from 5.53 to 19.24 g with an average of 10.67. The range of kernel weight was 1.78-9.28 g with an average of 4.83. Kernel percentage in 107 out of 362 genotypes studied was more than 50.00%. Multiple regression analysis (MRA) showed that kernel percentage was associated with kernel weight, nut weight, kernel filled, nut width, and shell thickness. Principal component analysis (PCA) showed that the characters related to nut and kernel size were correlated with the first component (PC1). Hierarchical cluster analysis (HCA) showed that the genotypes were clustered into two major clusters. Based on the most important commercial characters considered by breeders to select ideal walnuts, 15 superior genotypes were selected and are recommended for cultivation in the orchards and also can be used in breeding programs.
https://doi.org/10.1002/fsn3.2193