Horticulturae, Volume 8, Issue 1 (January 2022) – 83 articles

Apple replant disease (ARD), caused largely by soil-borne fungal pathogens, has seriously hindered the development of the apple industry. The use of antagonistic microorganisms has been confirmed as a low-cost and environmentally friendly means of controlling ARD. In the present study, we assessed the effects of Bacillus amyloliquefaciens QSB-6 on the growth of replanted apple saplings and the soil microbial environment under field conditions, thus providing a theoretical basis for the successful use of microbial biocontrol agents. Four treatments were implemented in three apple orchards: untreated replant soil (CK1), methyl bromide fumigation (CK2), blank carrier treatment (T1), and QSB-6 bacterial fertilizer treatment (T2). The plant height, ground diameter, and branch length of apple saplings treated with T2 in three replanted apple orchards were significantly higher than that of the CK1 treatment. Compared with the other treatments, T2 significantly increased the number of soil bacteria, the proportion of actinomycetes, and the activities of soil enzymes. By contrast, compared with the CK1 treatments, the phenolic acid content, the number of fungi, and the abundance of Fusarium oxysporum, Fusarium moniliforme, Fusarium proliferatum, and Fusarium solani in the soil were significantly reduced. PCoA and cluster analysis showed that soil inoculation with strain QSB-6 significantly decreased the Mcintosh and Brillouin index of soil fungi and increased the diversity of soil bacteria in T2 relative to CK1. The soil bacterial community structure in T2 was different from the other treatments, and the soil fungal communities of T2 and CK2 were similar. In summary, QSB-6 bacterial fertilizer shows promise as a potential bio-inoculum for the control of ARD. Full article

Ten genetically diverse inbred lines, including two genic male sterile lines, of muskmelon (Cucumis melo L.) were crossed in a half-diallel to generate 45 F₁ hybrids. These hybrids, along with the parental lines and commercial check, were evaluated for their fruit yield, level of phytochemicals and Fusarium wilt resistance. Both additive and non-additive genetic variances were important in governing the expression of all of the traits; however, the additive gene action for the fruit weight (g), flesh thickness (cm), rind thickness (mm), firmness (lb inch⁻²), β-carotene content (mg/100 g), non-additive variance for fruit yield (t ha⁻¹), fruit number, total soluble solids (TSS, °Brix), ascorbic acid (mg/100 g) and reaction to Fusarium wilt were comparatively more important. The parental line MM-625 was the best general combiner for fruit yield, rind thickness and β-carotene content (mg/100 g). The exotic line Riogold was the best combiner for flesh thickness and firmness. The netted inbred line MM-610 was the best general combiner for fruit weight, ascorbic acid and reaction to Fusarium wilt. The inbred lines KP₄HM-15 and MM-916 were the best general combiners for the number of fruits per vine and TSS. The best cross-combinations for fruit yield ha⁻¹ and TSS were MS-1×M-610 and Kajri×MM-904, respectively. The hybrids KP₄HM-15×MM Sel-103 and KP₄HM-15×MM-1831 recorded the highest standard heterosis for fruit yield and TSS. The landrace-derived inbred lines Kajri, MM Sel-103 and KP₄HM-15 produced moderate-to-highly FW-resistant hybrids. Out of the 121 SSR markers applied, 70 exhibited parental polymorphism. The markers DM0561, CMAAAGN14, TJ147, CMMS35_3, CMAGN45 and DE1337 identified specific/unique alleles in certain parental genotypes. Thus, the findings of this study revealed that the novel inbred lines can effectively be combined to generate heterotic F₁ hybrids for yield and other traits, such as rind and flesh thickness, TSS, β-carotene content and firmness. Furthermore, SSR markers can potentially be utilized to confirm the genetic diversity among the parental lines, and for the DNA fingerprinting of F₁ hybrids. Full article

Compact bunches have been often associated with higher susceptibility to Botrytis cinerea and therefore reduction in berry quality in grapevine. The objective of this study was to evaluate three management methods (early leaf removal, gibberellic acid, and their combination) for reducing bunch compactness in Vitis vinifera cv. Pinot gris trained in two different training systems with contrasting vigor (Guyot and pergola). Treatments were applied at BBCH 62 or BBCH 65 and yield components, total soluble solids, fruit set, and bunch compactness parameters were evaluated. Both treatments individually reduced berry number, mean bunches weight and bunches compactness as well as yield per vine when compared to control-untreated vines. However, no major differences were observed when both the treatments were applied in combination for Guyot or pergola although a higher reduction in yield was detected for Guyot and a significant increase in total soluble solids was observed in pergola. Our study suggests that intense leaf removal and gibberellic acid applied at early flowering can help reducing bunch compactness in Pinot gris and showing it in two training systems. In particular, leaf removal represents a valuable alternative to plant growth regulators (i.e., gibberellic acid) as applicable in organic viticulture. Full article

Sweet osmanthus (Osmanthus fragrans) is an evergreen woody plant that emits a floral aroma and is widely used in the landscape and fragrance industries. However, its application and cultivation regions are limited by cold stress. Heat-shock transcription factor (HSF) family members are widely present in plants and participate in, and regulate, the defense processes of plants under various abiotic stress conditions, but now, the role of this family in the responses of O. fragrans to cold stress is still not clear. Here, 46 OfHSF members were identified in the O. fragrans genome and divided into three subfamilies on the basis of a phylogenetic analysis. The promoter regions of most OfHSFs contained many cis-acting elements involved in multiple hormonal and abiotic stresses. RNA-seq data revealed that most of OfHSF genes were differentially expressed in various tissues, and some OfHSF members were induced by cold stress. The qRT-PCR analysis identified four OfHSFs that were induced by both cold and heat stresses, in which OfHSF11 and OfHSF43 had contrary expression trends under cold stress conditions and their expression patterns both showed recovery tendencies after the cold stress. OfHSF11 and OfHSF43 localized to the nuclei and their expression patterns were also induced under multiple abiotic stresses and hormonal treatments, indicating that they play critical roles in responses to multiple stresses. Furthermore, after a cold treatment, transient expression revealed that the malondialdehyde (MDA) content of OfHSF11-transformed tobacco significantly increased, and the expression levels of cold-response regulatory gene NbDREB3, cold response gene NbLEA5 and ROS detoxification gene NbCAT were significantly inhibited, implying that OfHSF11 is a negative regulator of cold responses in O. fragrans. Our study contributes to the further functional characterization of OfHSFs and will be useful in developing improved cold-tolerant cultivars of O. fragrans. Full article

Limited water stress is one of the most important environmental stresses that affect the growth, quantity and quality of agronomic crops. This study was undertaken to investigate the effect of foliar applied salicylic acid (SA) on physiological responses, antioxidant enzymes and qualitative traits of Cucurbita pepo L. Plants exposed to water-stressed conditions in two years of field studies. Irrigation regimes at three soil matric potential levels (−0.3, −1.2 and −1.8 MPa) and SA at four levels (0.0, 0.5, 1.0 and 1.5 mg/L) were considered as main plot and sub-plots, respectively. The soil matric potential values (MPa) was measured just before irrigation. Results showed that under water stressed conditions alone, the amounts of malondialdehyde (MDA), hydrogen peroxide (H₂O₂) and ion leakage were higher compared with control treatment. However, spraying of SA under both water stress and non-stress conditions reduced the values of the above parameters. Water stress increased CAT, APX and GR enzymes activity. However foliar application of SA led to the decrease of CAT, APX and GR under all soil matric potential levels. The amount of carbohydrates and fatty acids increased with the intensity of water stress and SA modulated this response. By increasing SA concentration both in optimum and stress conditions, saturated fatty acids content decreased. According to our data, the SA application is an effective approach to improve pumpkin growth under water stress conditions. Full article

PARP proteins are highly conserved homologs among the eukaryotic poly (ADP-ribose) polymerases. After activation, ADP-ribose polymers are synthesized on a series of ribozymes that use NAD+ as a substrate. PARPs participate in the regulation of various important biological processes, such as plant growth, development, and stress response. In this study, we characterized the homologue of PARP1 in B. rapa using RNA interference (RNAi) to reveal the underlying mechanism responding to drought stress. Bioinformatics and expression pattern analyses demonstrated that two copy numbers of PARP1 genes (BrPARP1.A03 and BrPARP1.A05) in B. rapa following a whole-genome triplication (WGT) event were retained compared with Arabidopsis, but only BrPARP1.A03 was predominantly transcribed in plant roots. Silencing of BrPARP1 could markedly promote root growth and development, probably via regulating cell division, and the transgenic Brassica lines showed more tolerance under drought treatment, accompanied with substantial alterations including accumulated proline contents, significantly reduced malondialdehyde, and increased antioxidative enzyme activity. In addition, the findings showed that the expression of stress-responsive genes, as well as reactive oxygen species (ROS)-scavenging related genes, was largely reinforced in the transgenic lines under drought stress. In general, these results indicated that BrPARP1 likely responds to drought stress by regulating root growth and the expression of stress-related genes to cope with adverse conditions in B. rapa. Full article

The state-of-the-art technique to control slug pests in agriculture is the spreading of slug pellets. This method has some downsides, because slug pellets also harm beneficials and often fail because their efficiency depends on the prevailing weather conditions. This study is part of a research project which is developing a pest control robot to monitor the field, detect slugs, and eliminate them. Robots represent a promising alternative to slug pellets. They work independent of weather conditions and can distinguish between pests and beneficials. As a prerequisite, a robot must be able to reliably identify slugs irrespective of the characteristics of the surrounding conditions. In this context, the utilization of computer vision and image analysis methods are challenging, because slugs look very similar to the soil, particularly in color images. Therefore, the goal of this study was to develop an optical filter-based system that distinguishes between slugs and soil. In this context, the spectral characteristics of both slugs and soil in the visible and visible near-infrared (VNIR) wavebands were measured. Conspicuous maxima followed by conspicuous local minima were found for the reflection spectra of slugs in the near infrared range from 850 nm to 990 nm]. Thus, this enabled differentiation between slugs and soils; soils showed a monotonic increase in the intensity of the relative reflection for this wavelength. The extrema determined in the reflection spectra of slugs were used to develop and set up a slug detector device consisting of a monochromatic camera, a filter changer and two narrow bandpass filters with nominal wavelengths of 925 nm and 975 nm. The developed optical system takes two photographs of the target area at night. By subtracting the pixel values of the images, the slugs are highlighted, and the soil is removed in the image due to the properties of the reflection spectra of soils and slugs. In the resulting image, the pixels of slugs were, on average, 12.4 times brighter than pixels of soil. This enabled the detection of slugs by a threshold method. Full article

Altering the growing temperature during controlled-environment production not only influences crop growth and development, but can also influence volatile organic compound (VOC) production and, subsequently, sensory attributes of culinary herbs. Therefore, the objectives of this study were to (1) quantify the influence of mean daily temperature (MDT) and daily light integral (DLI) on key basil phenylpropanoid and terpenoid concentrations, (2) determine if differences in sensory characteristics due to MDT and DLI influence consumer preference, and (3) identify the sweet basil attributes consumers prefer. Thus, 2-week-old sweet basil ‘Nufar’ seedlings were transplanted into deep-flow hydroponic systems in greenhouses with target MDTs of 23, 26, 29, 32, or 35 °C and DLIs of 7, 9, or 12 mol·m⁻²·d⁻¹. After three weeks, the two most recently mature leaves were harvested for gas chromatography–mass spectrometry (GC–MS) and consumer sensory analysis. Panel evaluations were conducted through a sliding door with samples served individually while panelists answered Likert scale and open-ended quality attribute and sensory questions. The DLI did not influence VOC concentrations. Increasing MDT from 23 to 36 °C during production increased 1,8 cineole, eugenol, and methyl chavicol concentrations linearly and did not affect linalool concentration. The increases in phenylpropanoid (eugenol and methyl chavicol) were greater than increases in terpenoid (1,8 cineole) concentrations. However, these increases did not impact overall consumer or flavor preference. The MDT during basil production influenced appearance, texture, and color preference of panelists. Taken together, MDT during production influenced both VOC concentrations and textural and visual attribute preference of basil but did not influence overall consumer preference. Therefore, changing the MDT during production can be used to alter plant growth and development without significantly affecting consumer preference. Full article

Water salinity is one of the major abiotic stresses, and the use of saline water for the agricultural sector will incur greater demand in the coming decades. Recently, nanoparticles (NPs) have been used for developing numerous plant fertilizers as a smart and powerful form of material with dual action that can alleviate the adverse effects of salinity and provide the plant with more efficient nutrient forms. This study evaluated the influence of calcium phosphate NPs (CaP-NPs) as a soil fertilizer application on the production and bioactive compounds of broad bean plants under salinity stress. Results showed that salinity had deleterious effects on plant yield with 55.9% reduction compared to control. On the other hand, CaP-NPs dramatically improved plant yield by 30% compared to conventional fertilizer under salinity stress. This improvement could be attributed to significantly higher enhancement in total soluble sugars, antioxidant enzymes, proline content, and total phenolics recorded use of nano-fertilizer compared to conventional use under salt stress. Additionally, nano-fertilizer reflected better mitigatory effects on plant growth parameters, photosynthetic pigments, and oxidative stress indicators (MDA and H₂O₂). Therefore, our results support the replacement of traditional fertilizers comprising Ca²⁺ or P with CaP-nano-fertilizers for higher plant productivity and sustainability under salt stress. Full article

The nematode family, Anguinidae, is a diverse group of polyphagous nematodes, generally known as fungal feeders or parasites of aerial plant parts. Here, we present the morphological and molecular characterization of adult females of two Nothotylenchus species, N. medians and N. similis, along with host association and geographical distribution data of the genus. Both species are recorded as new reports from Canada and designated as reference populations for future studies. Morphological or morphometrical variation was not observed in the Canadian population of N. medians and N. similis, in comparison with the original description. Phylogenetic analyses based on 18S and D2–D3 of 28S genes placed both species within Anguinidae. Since the biology of the genus Nothotylenchus has not been rigorously characterized, the habitat and distribution information presented in this study will shed some light on the ecology of these nematodes. Notably, the detection of N. medians and N. similis in our nematode inventory survey indicates that considerable Nothotylenchus diversity is hidden in these soils. Consequently, increased surveys and more in-depth research are needed to explore the full diversity of anguinids inhabiting these cultivated areas. Full article

Grapevine (Vitis spp.) is globally one of the most economically important fruit crops. China is the largest grapevine-growing country of the world and Shaanxi province is one of the major grapevine-growing provinces in the country. A survey of GLRaV-3 found it widespread, with 57–100% infection frequencies, in both wine and table grapevine cultivars of three grapevine-growing regions of Shaanxi province. The virus infection frequencies varied with cultivars and regions. In order to obtain the full genomic length of a new GLRaV-3 isolate, GLRaV-3-Sau (accession number MK988555), was sequenced. This isolate has a genome of 18026 nucleotides, and 14 open reading frames (ORFs). The full-genome of the isolate GLRaV-3-Sau shared 85.88% nucleotide identity to GLRaV-3-LN, another isolate found in China. Coat protein (CP) genes of GLRaV-3 isolates were identical (99%) to the Vitis vinifera isolate (accession number HQ185608.1) from the USA. Immunohistochemistry for virus localization found that distribution patterns were similar in red-berried cultivar ‘Cabernet Sauvignon’ and white-berried cultivar ‘Chardonnay’, and GLRaV-3 is restricted in phloem tissue of vascular bundles. Virus transmission by micrografting found virus transmission efficiency was higher in ‘Chardonnay’ and ‘Thompson Seedless’ than in ‘Hunan-1’, indicating that ‘Hunan-1’ was less sensitive to GLRaV-3. As far as we know, these are the most comprehensive comparisons on the genome and CP genes of GLRaV-3 worldwide and the first to have found that the grapevine ‘Hunan-1’ is less susceptible to GLRaV-3. Full article

The aim of this study was to evaluate physiological responses to short-term heat stress in the leaves of traditional (Bistrica) and modern (Toptaste) plum cultivars. In this study, detached plum leaves were incubated at 25 °C (control) and 40 °C (stress). After 1 h of exposure to heat (40 °C), chlorophyll a fluorescence transients were measured, and several biochemical parameters were analyzed. Elevated temperature caused heat stress in both plum cultivars, seen as a decrease in water content (WT), but in the leaves of the cultivar Bistrica, an accumulation of proline and phenols, as well as an accumulation of photosynthetic pigments, suggest the activation of a significant response to unfavorable conditions. Conversely, in the leaves of Toptaste, a significant accumulation of malondialdehyde (MDA) and an activation of guaiacol peroxidase (GPOD), all together with a decreased soluble proteins content, indicate an inadequate response to maintaining homeostasis in the leaf metabolism. The impact of an elevated temperature on photosynthesis was significant in both plum cultivars as reflected in the decrease in performance indexes (PI_ABS and PI_total) and the maximum quantum yield of PSII (F_v/F_m), with significantly pronounced changes found in Toptaste. Unlike the traditional plum cultivar, Bistrica, in the modern cultivar, Toptaste, short-term heat stress increased the minimal fluorescence (F₀) and absorption (ABS/RC), as well as Chl b in total chlorophylls. Additionally, the inactivation of RCs (RC/ABS) suggests that excitation energy was not trapped efficiently in the electron chain transport, which resulted in stronger dissipation (DI₀/RC) and the formation of ROSs. Considering all presented results, it can be presumed that the traditional cultivar Bistrica has better tolerance to heat stress than the modern cultivar Toptaste. The cultivar, Bistrica, can be used as a basis in further plum breeding programs, as a source of tolerance for high temperature stress. Full article

Microgreens are considered products of high biological value because they contain natural and beneficial metabolites and antioxidants in high amounts; also, consumers appreciate them very much for their aromas. In this work, we focused our attention on the volatile organic compounds (VOCs) emitted from whole fresh leaves of two Chinese basil varieties (Perilla frutescens var. frutescens and var. crispa) at the microgreens stage; to show that the emission is microgreens specific we tested whether this capacity remains during subsequent growth of the plants. We found differences between the VOCs produced by the leaves of the two varieties at the microgreens stage and significantly reduced emission after development (additional four weeks of growth) particularly for the green variety (var. frutescens). The main volatiles emitted by whole leaves were D-Limonene for the red variety (crispa) and 2-Hexanoylfuran for the green one. In addition, the total phenolic content (TPC) and antioxidant power increase in adult leaves. These results clearly indicate that the particular smell of microgreens Perilla leaves depends on the specific variety and is not related to the amount of total phenols or antioxidant capacity of the leaves. Full article

Banana is one of the most produced and consumed fruits in the world and its fruit peel accounts for about 40% of the total fresh quantity of ripe fruit, which is usually regarded as waste and poses serious environmental hazards. However, it is a promising source of natural bioactive compounds including phenolic compounds. Determination of the phenolic compounds in fruit peel from different cultivars and subgroups over a range of maturities provides convincing information for making full use of them. This study developed a sensitive and reliable analytical method—ultra-high performance liquid chromatography—coupled with electrospray ionization tandem mass spectrometry (UPLC-MS/MS) for measuring phenolic compounds in fruit peel from different ecotype cultivars and subgroups with different maturity. The results showed that quinic acid had the highest concentration ratio among the main phenolic compounds in the green/ripe peel of all banana cultivars; among all banana cultivars, the total phenolic compound contents of green banana peel were significantly higher than that of ripe banana peel; the total phenolic compound contents in the green/ripe fruit peel of non-dessert bananas were significantly higher than that of dessert bananas (green: non-dessert banana 1.48 ± 0.44 mg/g vs. dessert banana 0.97 ± 0.12 mg/g; ripe: non-dessert banana 0.26 ± 0.13 mg/g vs. dessert banana 0.19 ± 0.06 mg/g). These data provide a basis for the rational utilization of phenolic compound extractions from banana peel with huge biomass in the next step. Full article

Phytoremediation with hyperaccumulator plants has been recognized as a potential way for the clearing of cadmium (Cd)-contaminated soil. In this study, hyperaccumulator Tagetes patula was treated with seven concentrations of Cd, ranging from 0 to 300 mg kg⁻¹. The Cd enrichment and nutrient contents in different organs during different growth phases were investigated. Under Cd concentrations ≤75 mg kg^-1, the morphological growth of T. patula did not change significantly regardless of growth stage. However, when Cd concentration exceeded 150 mg kg⁻¹, the morphological growth was remarkedly inhibited. The root/shoot ratio remained unchanged except for at 300 mg kg⁻¹. In addition, Cd negatively influenced the flowering process at the concentration of 300 mg kg⁻¹. Cd content increased significantly in Cd-treated plants. Nitrogen absorption was increased under Cd treatments, and phosphorus content was also increased under concentration ≤150 mg·kg⁻¹. However, the potassium content in the flower was decreased under 300 mg kg⁻¹. Furthermore, the contents of H₂O₂, O²⁻ and malondialdehyde were increased during the seedling phase, especially when Cd concentration was ≥150 mg kg⁻¹. In summary, T. patula showed a strong ability to tolerate Cd, and such ability might be explained by nutrient absorption and reactive oxygen clearness. Full article

Chitosan oligosaccharides (COS) has been abundantly studied for its application on regulating plant growth of many horticultural and agricultural crops. We presented here the effect of COS on tea plant growth and yield by physiological and transcriptomic checking. The results showed that COS treatment can enhance the antioxidant activity of superoxide dismutase (SOD) and peroxidase (POD) and increase the content of chlorophyll and soluble sugar in tea plants. The field trail results show that COS treatment can increase tea buds’ density by 13.81–23.16%, the weight of 100 buds by 15.94–18.15%, and the yield by 14.22–21.08%. Transcriptome analysis found 5409 COS-responsive differentially expressed genes (DEGs), including 3149 up-regulated and 2260 down-regulated genes, and concluded the possible metabolism pathway that responsible for COS promoting tea plant growth. Our results provided fundamental information for better understanding the molecular mechanisms for COS’s acting on tea plant growth and yield promotion and offer academic support for its practical application in tea plant. Full article

Wood apple (Limonia acidissima L.) is an underutilized, fruit-yielding tree that is native to India and Sri Lanka. Wood apple trees are also cultivated in India, Sri Lanka, Bangladesh, Myanmar, Thailand, Malaysia, Vietnam, Kampuchea, Laos, and Indonesia for delicious fruits and medicinal purposes. The major objective of the present work was the analysis of the nutritional status of wood apple fruit pulp.The fruits are rich in total carbohydrates (24.74 ± 0.19%), total proteins (9.30 ± 0.16%), oil (0.99 ± 0.01%), fiber (3.32 ± 0.02%), and ash (2.73 ± 0.12%). Further analysis and quantification of free sugars, organic acids, and fatty acid methyl esters were carried out by using high-performance liquid chromatography (HPLC) and gas chromatographic (GC) methods. In total, five sugars and nine organic acids were detected and quantified. The predominant sugars were fructose (16.40 ± 0.23%) and glucose (14.23 ± 0.10%), whereas the predominant organic acids were D-tartaric (4.01 ± 0.03%), ascorbic (4.51 ± 0.05%), and citric acid (4.27 ± 0.04%). The oil content of fruit pulp was 0.99 ± 0.01% and GC-MS analysis revealed that, it comprise of 16 fatty acid methyl esters. The percentage of saturated fatty acids were 32.17 ± 0.35%, that includes palmitic (18.52 ± 0.12%) and stearic acids (9.02 ± 0.08%), whereas, the unsaturated fatty acids were 51.98 ± 0.94%, including oleic acid (23.89 ± 0.06%), α-linolenic acid (16.55 ± 0.26%), linoleic acid (10.02 ± 0.43%), and vaccenic acid (1.78 ± 0.23%). Full article

European fodder turnips (Brassica rapa ssp. rapifera) were identified as sources of clubroot resistance (CR) and have been widely used in Brassica resistance breeding. An F₂ population derived from a cross between a resistant turnip and a susceptible Chinese cabbage was used to determine the inheritance and locating the resistance Quantitative Trait Loci (QTLs). The parents showed to be very resistant/susceptible to the field isolates (pathotype 4) of clubroot from Henan in China. After inoculation, 27 very resistant or susceptible individuals were selected to construct bulks, respectively. Next-generation-sequencing-based Bulk Segregant Analysis Sequencing (BSA-Seq) was used and located resistance QTL on chromosome A03 (3.3–7.5 Mb) and A08 (0.01–6.5 Mb), named Bcr1 and Bcr2, respectively. Furthermore, an F₃ population including 180 families derived from F₂ individuals was phenotyped and used to verify and narrow candidate regions. Ten and seven Kompetitive Allele-Specific PCR (KASP) markers narrowed the target regions to 4.3–4.78 Mb (A03) and 0.02–0.79 Mb (A08), respectively. The phenotypic variation explained (PVE) of the two QTLs were 33.3% and 13.3% respectively. The two candidate regions contained 99 and 109 genes. In the A03 candidate region, there were three candidate R genes, namely Bra006630, Bra006631 and Bra006632. In the A08 candidate region, there were two candidate R genes, namely Bra030815 and Bra030846. Full article

Floral scent plays an important ecological role attracting pollinators. Its composition has been elucidated for a vast diversity of species and is dominated by volatile organic compounds (VOCs) such as monoterpenoids, sesquiterpenoids, phenylpropanoids and benzenoid compounds. Considering that floral scent is also an important character for the ornamental plant market, this study was aimed at characterizing and comparing the molecular composition of scented and non-scented alstroemeria flowers. Confirmation of floral scent was performed through sensorial analysis, while GC-MS analysis detected monoterpenes and esters as major volatile organic compounds (VOCs). A total of 19 and 17 VOCs were detected in the scented hybrids 13M07 and 14E07, respectively. The non-scented hybrid 13B01 shared 14 VOCs with the scented hybrids, although it showed different relative concentrations. Comparison between scented and non-scented hybrids suggests that diversity and amounts of VOCs are likely due to the ecological role of scent, while the human perception of floral scent is not strictly related to the VOC profile. Full article

The large number of cultivars belonging to the cultivated apple (Malus × domestica Borkh.) reflects an extremely wide range of variability, including for fruit quality traits. To evaluate some characteristics of fruit quality, 22 apple genotypes were selected from a collection of germplasms containing more than 600 accessions, based on different considerations, including the use of fruits (dessert, cooking, processing, juice, cider, multipurpose). The mean water content of the studied apple genotypes was 85.05%, with a coefficient of variation (CV) of 2.74%; the mean ash content was 2.32% with a CV of 22.1%, and the mean total soluble solids was 16.22% with a CV of 17.78%, indicating a relatively small difference between genotypes for these indices. On the contrary, relatively large differences were registered between genotypes for fruit weight, volume, and titratable acidity with means of 119.52 g, 155 mL, and 0.55% malic acid, and CVs of 35.17%, 34.58%, and 54.3%, respectively. The results showed that peel hardness varied between 3.80 and 13.69 N, the toughness between 0.2 and 1.07 mm, the flesh hardness between 0.97 and 4.76 N, and the hardness work between 6.88 and 27.84 mJ. The current study can emphasize the possibility of choosing the appropriate apple cultivars to cross in the breeding process and how future strategies can help apple breeders select breeding parents, which are essential key steps when breeding new apple cultivars. In addition, multivariate analysis has proven to be a useful tool in assessing the relationships between Malus genetic resources. Full article

Cytokinin oxidase/dehydrogenases (CKXs) are the key enzymes in cytokinin degradation and have been widely studied in model plants. Little is known about apple’s (Malus×domestica) CKX genes. Here, using genome-wide analysis, we identified 10 MdCKX genes in apple. The phylogenetics, chromosome locations, and genome structures were then tested. Expression analysis showed that MdCKX genes had different expression profiles in apple, pointing to the different roles. Meanwhile, relative expression analysis showed that these genes have different expression patterns in response to several exogenous cytokinin factors, including trans-zeatin (ZT), thidiazuron (TDZ), and N6-furfuryladenine (KT). Finally, we introduced the MdCKX5.2 gene into Arabidopsis to evaluate its functions, and the results suggested the transgenic Arabidopsis displayed phenotypes related to promoting primary root and lateral root development, response to exogenous ZT, and conferring to drought and salt tolerant. Taken together, our results provide insights on the possible application of the MdCKX5.2 gene for molecular breeding in apples. Full article

Soil with low fertility is a big problem for achieving citrus productivity. In this regard, the management of macro and micronutrients is essential. Macro and micronutrient deficiency decreased the yield and the quality of citrus fruit. It is the need of the hour to classify the soil fertility status under changing climatic scenarios. The current soil fertility survey was conducted to examine the macro and micronutrient status in the citrus production area. In soil, three depths (0–15, 15–30, and 30–45 cm) were taken for sampling. For leaves, 4–6-months-old non-bearing twigs were sampled from 20 trees per orchard at breast height. Results showed that soil pH (7.1–8.4) was slightly alkaline, electrical conductivity (EC) was non-saline (<4 dSm⁻¹), soil organic matter (SOM) was deficient (<0.86%), and calcium carbonate (CaCO₃) was slight calcareous (<8%), at 0–15, 15–30, and 30–45 cm depths. The majority of soil samples were low in nitrogen (N) contents at all depths, i.e., (<0.043) 0–15 (85%), 15–30 (97%), and 30–45 (100%) cm depths. Phosphorus (P) was medium (7–15 mg kg⁻¹) at 0–15 cm (60%) but low (<7 mg kg⁻¹) at 15–30 (63%) and 30–45 cm (82%) depths. Potassium (K) was medium (80–180 mg kg⁻¹) at 0–15 (69%), 15–30 (69%), and 30–45 cm (10%) depths. Boron (B) and manganese (Mn) were medium, and Cu was high in 0.15 cm, but all were low at 15–30 and 30–45 cm depths. Iron (Fe) and zinc (Zn) were low at depths of 0–15, 15–30, and 30–45 cm. Most citrus leaves were deficient in N (94%), Fe (76%), Zn (67%), and B (67%). In conclusion, soil fertilization is not sufficient for optimum citrus yield because of alkaline pH and slight calcareous soil conditions in this region. Foliar application of nutrients is suggested instead of only soil fertilization, for better nutrient management in citrus orchards. Full article

The objective of this study was to investigate the growth and light-intercepting characteristics of tomatoes when movable benches are used in their cultivation. We cultivated tomatoes in a greenhouse (168 m²) during summer (9 July–9 September 2018) under different furrow distances (F1.0 = 1.0 m and F1.6 = 1.6 m) and movable benches (M indicates that the furrow distance = 0.4–0.8 m). Compared to the other treatments, when the movable bench was used to the change furrow distance depending on the plant growth stage (M treatment), the percentage of canopy light interception increased to ~90% at the early stage of plant growth (~20 days after transplanting). The percentage of canopy light interception for different treatments increased in the order of M > F1.0 > F1.6, and it increased towards the end of cultivation. In addition, the yield per unit area exhibited the same trend. Therefore, the solar radiation inside a greenhouse can be efficiently intercepted by plants when movable benches are used. This indicated that it was possible to increase plant yield per unit area using movable benches in plant cultivation. Full article

Hydroponic cultivation of vegetables avoids problems with soil-borne plant pathogens and may allow higher yield. In arid climates and particularly on islands, high concentrations of sodium chloride can be present in the groundwater. For instance, in many sites of Malta, the groundwater contains more than 10 mM sodium chloride. Here we investigated the effects of sodium chloride at levels typically found in Malta on yield, physiology and fruit quality of tomato, the economically most important vegetable. We selected cherry tomatoes since their production is attractive due to their high marketing value. While the yield declined at higher salinity levels tested (17 and 34 mM), the quality increased significantly as indicated by higher total soluble solids and fructose and glucose levels. The type of substrate—coco peat, perlite or Rockwool—had only minor effects. Although the concentration of citric acid and malic acid remained unaffected, the pH dropped by approximately 0.1 unit and the titratable acidity increased slightly. This might be explained by a high uptake of chloride but a lower increase of the sodium content and a reduced potassium level in the fruits, shifting the equilibrium of the organic acids more to their protonated forms. Proline increased significantly, while the level of glutamic acid, which is crucial for the taste, remained unchanged. Our results show that cherry tomatoes can be cultivated in nutrient solutions prepared with salt-containing groundwater, as found in Malta. The yield declined to some extent but the quality of the produced fruits was higher compared to cultivation in salt-free media. Full article

Cyanobacteria, also called blue-green algae, are a group of prokaryotic microorganisms largely distributed in both terrestrial and aquatic environments. They produce a wide range of bioactive compounds that are mostly used in cosmetics, animal feed and human food, nutraceutical and pharmaceutical industries, and the production of biofuels. Nowadays, the research concerning the use of cyanobacteria in agriculture has pointed out their potential as biofertilizers and as a source of bioactive compounds, such as phycobiliproteins, for plant pathogen control and as inducers of plant systemic resistance. The use of alternative products in place of synthetic ones for plant disease control is also encouraged by European Directive 2009/128/EC. The present up-to-date review gives an overall view of the recent results on the use of cyanobacteria for both their bioprotective effect against fungal and oomycete phytopathogens and their plant biostimulant properties. We highlight the need for considering several factors for a proper and sustainable management of agricultural crops, ranging from the mechanisms by which cyanobacteria reduce plant diseases and modulate plant resistance to the enhancement of plant growth. Full article

Turnip mosaic virus (TuMV), which is distributed almost all over the world and has a wide range of hosts, mainly brassica crops, was first described in Brassica rapa in the USA. Plant volatile compounds play an important role in the host searching behavior of natural enemies of herbivorous insects. In this study, TuMV-inoculated resistant and susceptible B. rapa lines were tested using volatile metabolome and transcriptome analyses. In volatile metabolome analysis, the volatile organic compounds (VOCs) were different after inoculation with TuMV in resistant B80124 and susceptible B80461, and the degree of downregulation of differentially expressed metabolites was more obvious than the degree of upregulation. Through transcriptome analysis, 70% of differentially expressed genes were in biological process, especially focusing on defense response, flavonoid biosynthetic process, and toxin metabolic process, which indicates that TuMV stress maybe accelerate the increase of VOCs. Integrating the metabolome and transcriptome analyses, after inoculating with TuMV, auxin regulation was upregulated, and ARF, IAA and GH3 were also upregulated, which accelerated cell enlargement and plant growth in tryptophan metabolism. The different genes in zeatin biosynthesis pathways were downregulated, which reduced cell division and shoot initiation. However, the metabolite pathways showed upregulation in brassinosteroid biosynthesis and α-linolenic acid metabolism, which could cause cell enlargement and a stress response. This study determined the difference in volatiles between normal plants and infected plants and may lay a foundation for anti-TuMV research in B. rapa. Full article

The value of home gardens has become more apparent among tenants forced into isolation in difficult and uncertain times arising since the COVID-19 pandemic started at the beginning of 2020. While gardens make a significant contribution to the social and ecological environment of cities, most studies have focused on public green spaces. Investigating householder preferences for gardens during and after the mandatory lockdown period in the UAE is required. The main objective of this study is to analyze the householder’s attitude, preferences, and willingness to have home gardens during the pandemic and after. The data were collected via an online survey of randomly selected respondents. A logistic econometrical model was utilized to analyze the factors affecting respondent preferences regarding having a garden. According to the results, the probability of having a garden increases among respondents who produce some crops, have attained Msc/PhD. level, a backyard, and a larger space to cultivate. It decreases among those who are married, find it hard to take care of a garden, and face a weed problem. In conclusions, it is highly recommended for householders to have home gardens, which can provide a quality lifestyle and enhance leisure time during the pandemic and after. Full article

This study evaluated the effective pollination period (EPP) in four European plum (Prunus domestica L.) cultivars (‘Mallard’, ‘Edda’, ‘Jubileum’, and ‘Reeves’) during two years (2018–2019) under the environmental conditions in western Norway. The pollination of plum cultivars was carried out one, three, five, seven, and nine days after anthesis (DAA) with a pollen mix of two compatible cultivars (‘Victoria’ and ‘Opal’). Initial, middle-season, and final fruit set was recorded after one month and two months after pollination and just before the harvest, respectively. On average from both years cultivar ‘Jubileum’ had the highest fruit set when pollinated one, three, five, seven, and nine DAA (33.23%, 30.83%, 8.47%, 3.08%, and 1.15%, respectively), which was more than two folds higher fruit set than in the other studied cultivars. Cultivar ‘Jubileum’ showed significantly reduced fruit set between pollination on five and nine DAA, while cultivars ‘Mallard’, ‘Edda’, and ‘Reeves’ had markedly reduced fruit set if pollinated three to five DAA, implying that the EPP in ‘Jubileum’ was five days while in the rest it was three days. Variation of weather conditions during the flowering period in both years did not have a major effect on the receptivity of stigmas in the studied plum cultivars, which means that the existing differences in the length of EPP is maternal-genotype dependent. Full article

Native potatoes are the most diverse among cultivated potato species and thus constitute a valuable source for identifying genes for potato improvement. Nevertheless, high-density mapping, needed to reveal allelic diversity, has not been performed for native Argentinian potatoes. We present a study of the genetic variability and population structure of 96 Andigena potatoes from Northwestern Argentina performed using a subset of 5035 SNPs with no missing data and full reproducibility. These high-density markers are distributed across the genome and present a good coverage of genomic regions. A Bayesian approach revealed the presence of: (I) a major group comprised of most of the Andean accessions; (II) a smaller group containing the out-group cv. Spunta and the sequenced genotype DM; and (III) a third group containing colored flesh potatoes. This grouping was also consistent when maximum likelihood trees were constructed and further confirmed by a principal coordinate analysis. A group of 19 accessions stored as Andean varieties clustered consistently with group Tuberosum accessions. This was in agreement with previous studies and we hypothesize that they may be reintroductions of European-bred long day-adapted potatoes. The present study constitutes a valuable source for allele mining of genes of interest and thus provides a tool for association mapping studies. Full article