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Purpose: We explored the elicitation role of the laser irradiations on the alleviation of nutrient-deficiency induced damage in anthocyanin-producing red-fleshed apple cell suspension in continuous production of anthocyanin. Methods: Anthocyanin-producing red-fleshed apple cells were irradiated by 4 intensity levels of red He-Ne (RHNL) and blue diode (BDL) lasers for 20 min. Results: Nutrient deficiency indicated negative effect on total soluble proteins (TSP), superoxidase dismutase (SOD) activity, and total phenolics content (TPC) while it displayed a positive effect on malondialdehyde (MDA), total flavonoids content (TFC), O2-, H2O2-, and lipoxygenase (LOX) and polyphenol oxidase (PPO) activities in light controls, illustrating oxidative stress. The laser irradiations on suspension cells indicated variable effects on measured parameters and were time of growth-, levels of intensity-, and laser type-dependent. Likewise, the elicitation effects of lasers relied on a critical threshold among ROS generation and antioxidative system which determines the fate of cells against oxidative stress. The same trend was displayed by RHNL at 6.46 mWcm−2 intensity and BDL at 13.73 mWcm−2. These intensities resulted in a significant increase in SOD, APX, POD, and CAT activities and TSP, TPC, TFC, proline, and glycine betaine accumulation, while induced decrease in LOX, and PPO activities and MDA, and ROS generation, alleviating cellular injury from prolonged nutrient deficiency by diminishing lipid peroxidation and oxidative damages of cell membrane. Conclusion: Results suggested that lasers application on mitigating nutrient deficiency stress relied on establishing a suitable balance between ROS generation and antioxidative system, which enables the nutrient-starved anthocyanin-producing cells to continuously produce anthocyanin. [ABSTRACT FROM AUTHOR]

Diplocarpon coronariae is a fungal pathogen that is prevalent in low-input apple production. Over the past 15 years, it has become increasingly distributed in Europe. However, comprehensive insights into its biology and pathogenicity remain limited. One particular aspect is the rarity of the sexual morph of this pathogen, a phenomenon hitherto unobserved in Europe. Diplocarpon coronariae reproduces through a heterothallic mating system requiring at least two different mating types for sexual reproduction. Genes determining the mating types are located on the mating-type locus. In this study, D. coronariae strain DC1_JKI from Dresden, Germany, was sequenced and used to unravel the structure of the mating type locus. Using short-read and long-read sequencing methods, the first gapless and near-complete telomere-to-telomere genome assembly of D. coronariae was achieved. The assembled genome spans 51.2 Mbp and comprises 21 chromosome-scale contigs of high completeness. The generated genome sequence was used to in silico elucidate the structure of the mating-type locus, identified as MAT1-2. Furthermore, an examination of MAT1-1 and MAT1-2 frequency across a diverse set of samples sourced from Europe and Asia revealed the exclusive presence of MAT1-2 in European samples, whereas both MAT loci were present in Asian counterparts. Our findings suggest an explanation for the absence of the sexual morph, potentially linked to the absence of the second mating idiomorph of D. coronariae in European apple orchards. [ABSTRACT FROM AUTHOR]

Pollen carries extensive genetic information, which may provide clues regarding the kinship of Malus, whose genetic relationships are complex. In this study, the phenotypic variation of pollen from 107 Malus taxa was investigated using combined methods of intraspecific/interspecific uniformity testing, cluster analysis, and Pearson correlation analysis. The family aggregation distributions in Malus sections, species, and cultivars were analyzed to infer their pedigree relationships. The results showed that (1) compared with pollen size and morphology, aberrant pollen rate and ornamentation were highly interspecifically differentiated, but ornamentation was also intraspecifically unstable, especially perforation densities ( c. v. ¯ > 15%). (2) The pollen alteration direction from the original to the evolutionary population of Malus was large to small, with elliptic to rectangular morphologies, large and compact to small and sparse ridges, and low to high perforation densities. However, there was no significant change in pollen size. (3) The 107 studied taxa were divided into four groups. Malus species were relatively clustered in the same section, while homologous cultivars showed evidence of family aggregation distribution characteristics (92.60% of cultivars were clustered with their parents). (4) M. baccata and M. pumilar var. neidzwetzkyana were high-frequency parents, participating in 38.7% and 20.7% of cross-breeding, respectively. Overall, this study provides a reference for identifying Malus' pedigree relationship. [ABSTRACT FROM AUTHOR]

For ensuring a sustainable production of high-quality fruits, the fruit growing systems needs to adapt for climate change. Different irrigation strategies and their potential advantages for improving apple tree production of cultivar ‘Red Jonaprince’ in conditions of temperate climate were tested. The water regimes of the orchard were analysed through evapotranspiration balance and soil moisture. In apple trees, total growth, flowering intensity, total yield and yield in different fruit size classes including the crop load were evaluated. The results of the study confirm the need for supplementary irrigation of the trees, especially in years with high yields and evapotranspiration. Considering the lower susceptibility to drought of triploid apple tree cultivars, 50 % coverage of evapotranspiration helps to maintain their water needs throughout the vegetation season irrespectively to used irrigation strategy. However, the soil moisture should not fall under 50% of available soil water capacity. Optimal crop load of the cultivar should be with 3,2 m high crowns between 160–180 fruits per tree allowing with plant distance of 3,5×1,2 m production of 70–80 t/ha.

Although self-incompatibility in apples (Malus × domestica Borkh.) is regulated by a single S-locus with multiple S-haplotypes that comprise pistil S (S-RNase) and pollen S genes, it is not desirable in commercial orchards because it requires cross-pollination to achieve stable fruit production. Therefore, it is important to identify and characterize self-compatible apple cultivars. However, little is known about self-compatibility (SC) and its underlying molecular mechanisms in apples. In this study, we discovered that ‘Vered’, an early maturing and low chilling-requiring apple cultivar, exhibits stable SC, which was evaluated via self-pollination tests. The S-genotype of ‘Vered’ was designated as S24S39sm. Results of genetic analysis of selfed progeny of ‘Vered’ revealed that SC is associated with the S39sm-haplotype, and molecular analyses indicated that it is caused by alternative splicing and a 205-bp deletion in S39sm-RNase. These events induce frameshifts and ultimately produce the defective S39sm-RNase isoforms that lack their C-terminal half. These results enabled us to develop a 117-bp DNA marker that can be used to assist in the selection of self-compatible apples with the dysfunctional S39sm-RNase. Thus, analysis of ‘Vered’ provided insights into the molecular mechanism of the very rare trait of natural stylar-part SC. Moreover, ‘Vered’ is a valuable genetic resource for breeding cultivars with SC and/or low chilling requirement in apple. Our findings contribute to a better understanding of self-compatible molecular mechanisms in apple and provide for the accelerated breeding of self-compatible apple cultivars.Key message: This study identifies the apple cultivar, ‘Vered’, as a stylar-part self-compatible genetic resource. We reveal the molecular mechanism underlying self-compatibility and develop an efficient selection marker for the self-compatibility. [ABSTRACT FROM AUTHOR]

Fire blight, caused by the bacterial pathogen Erwinia amylovora, is a severe bacterial disease of apple and pear that can quickly destroy whole plants. In the last decade, it was also detected in Central Asia, where wild pomaceous fruit plants represent the dominant species in mid-altitude forests and constitute a critical foundation for the entire ecosystem. Efficiently informing farmers, forestry services and private persons about the instances and dangers of fire blight, the correct way to recognize the symptoms, and the methods of disease control is thus of paramount importance in a vast and fragmented natural landscape like the one characterizing countries like Kyrgyzstan, Kazakhstan and Tajikistan. For that purpose, we have developed an app for smartphones and mobile devices that can inform stakeholders about fire blight, simultaneously allowing a citizen science approach for mapping the spread of the disease in Central Asia. The app is available in the three national languages as well as in Russian, English, and German, and can easily be adapted to new countries, languages or even diseases. [ABSTRACT FROM AUTHOR]

The present study evaluates the phytotoxic effects of phloretin, a prevalent secondary metabolite of apple trees, on the broadleaf weed Capsella bursa-pastoris (L.) Medik. known for its resistant myxospermous seeds that form a long-lasting soil bank. The results indicate a significant, dose-dependent inhibitory effect of phloretin on the growth and morphological parameters of weed seedlings grown in vitro. Although the applied phloretin concentrations (250–1000 µM) were not lethal to the C. bursa-pastoris seedlings after two weeks, the metabolism of the seedlings was impaired, resulting in an accumulation of lipid droplets in the root tips and root hairs. Histochemical analysis shows deposits of phenols in the root epidermal cells, which are probably aggregates of phloretin or its metabolic derivatives. The accumulation of pectin in the cell walls of root border cells in phloretin-treated seedlings indicates an attempt to reduce the uptake of phloretin and reduce its concentration in the cells. Inhibition of shoot growth associated with chlorosis and reduced photosynthetic pigment content is a consequence of seedling exposure to phloretin. This study provides a basis for further evaluation of phloretin as a new bioherbicidal compound and for elucidating the mechanism underlying its phytotoxic activity. [ABSTRACT FROM AUTHOR]

There is limited information on the compared performances of biological, serological, and molecular assays with high-throughput sequencing (HTS) for viral indexing in temperate fruit crops. Here, using a range of samples of predetermined virological status, we compared two performance criteria (inclusivity and analytical sensitivity) of enzyme-linked immunosorbent assay (ELISA), molecular hybridization, reverse transcription (RT)-PCR, and double-stranded RNA (dsRNA) HTS for the detection of a total of 14 viruses (10 genera) and four viroids (three genera). When undiluted samples from individual plants were used, ELISA had the lowest performance, with an overall detection rate of 68.7%, followed by RT-PCR (82.5%) and HTS (90.7%; 100% if considering only viruses). The lower performance of RT-PCR reflected the inability to amplify some isolates as a consequence of point mutations affecting primer-binding sites. In addition, HTS identified viruses that had not been identified by other assays in nearly two-thirds of the samples. Analysis of serial dilutions of fruit tree samples allowed comparison of analytical sensitivities for various viruses. ELISA showed the lowest analytical sensitivity, but RT-PCR showed higher analytical sensitivity than HTS for most of lhe samples. Overall, these results confirm the superiority of HTS over biological indexing in terms of speed and inclusivity and show that while the absolute analytical sensitivity of RT-PCR tends to be higher than that of HTS, PCR inclusivity is affected by viral genetic diversity. Taken together, these results make a strong case for the implementation of HTS-based approaches in fruit tree viral testing protocols supporting quarantine and certification programs. [ABSTRACT FROM AUTHOR]

Diplocarpon coronariae is a fungal pathogen that is prevalent in low-input apple production. Over the past 15 years, it has become increasingly distributed in Europe. However, comprehensive insights into its biology and pathogenicity remain limited. One particular aspect is the rarity of the sexual morph of this pathogen, a phenomenon hitherto unobserved in Europe. Diplocarpon coronariae reproduces through a heterothallic mating system requiring at least two different mating types for sexual reproduction. Genes determining the mating types are located on the mating-type locus. In this study, D. coronariae strain DC1_JKI from Dresden, Germany, was sequenced and used to unravel the structure of the mating type locus. Using short-read and long-read sequencing methods, the first gapless and near-complete telomere-to-telomere genome assembly of D. coronariae was achieved. The assembled genome spans 51.2 Mbp and comprises 21 chromosome-scale contigs of high completeness. The generated genome sequence was used to in silico elucidate the structure of the mating-type locus, identified as MAT1-2. Furthermore, an examination of MAT1-1 and MAT1-2 frequency across a diverse set of samples sourced from Europe and Asia revealed the exclusive presence of MAT1-2 in European samples, whereas both MAT loci were present in Asian counterparts. Our findings suggest an explanation for the absence of the sexual morph, potentially linked to the absence of the second mating idiomorph of D. coronariae in European apple orchards.

In 2017–2023, a rootstock trial was conducted at VŠÚO Holovousy with apple varieties ‘Gala’ and ‘Red Jonaprince’ grafted onto rootstocks of the Geneva series – G11, G16, G41 and clones of rootstock M9 – T337, Pajam1, Pajam2, RN29, Fl56. Total yield, yield efficiency, average fruit weight, trunk cross-sectional area (TCSA) and tree crown volume were evaluated during the experiment. The highest cumulative yield for ‘Gala’ was recorded on rootstock G41, where there was a significant difference compared to the other rootstocks, while the lowest value in this parameter was measured on rootstock Pajam1. The highest yield efficiency calculated as cumulative yield to TCSA and to tree crown volume for this variety was found on rootstocks G41 and G11. The lowest value for yield efficiency to TCSA was recorded on rootstock G16 and for yield efficiency to crown volume on rootstocks Fl56 and Pajam2. The average fruit weight for the cultivar ‘Gala’ was the highest on rootstock G41 and the lowest on G16. For growth parameters on the same cultivar, the highest values for TCSA were measured on rootstocks RN29 and G41, and for tree crown volume on Pajam2 and RN29. On the other hand, the lowest values for TCSA were measured on rootstocks Pajam1, Fl56 and G11, and again for tree crown volume on Pajam1. For the cultivar ‘Red Jonaprince’, the highest cumulative yield was found on rootstock G11, which was significantly higher than on rootstock Pajam1, which had the lowest values. The cumulative yield for the same cultivar, either to TCSA or to tree crown volume, was found to be the highest on rootstocks G11 and G41, the lowest values for this parameter converted to TCSA were measured on rootstock T337, and to tree crown volume on Pajam1. The average fruit weight of 'Red Jonaprince' was the highest on rootstock RN29, and the lowest on G16. RN29 showed the best growth values for both TCSA and tree crown volume, while the lowest values for both parameters were obtained by the rootstock Pajam1 for ‘Red Jonaprince’ variety.

Identification of the S genotype of Malus plants will greatly promote the discovery of new genes, the cultivation and production of apple, the breeding of new varieties, and the origin and evolution of self-incompatibility in Malus plants. In this experiment, 88 Malus germplasm resources, such as Aihuahong, Xishuhaitang, and Reguanzi, were used as materials. Seven gene-specific primer combinations were used in the genotype identification. PCR amplification using leaf DNA produced a single S-RNase gene fragment in all materials. The results revealed that 70 of the identified materials obtained a complete S-RNase genotype, while only one S-RNase gene was found in 18 of them. Through homology comparison and analysis, 13 S-RNase genotypes were obtained: S1S2 (Aihuahong, etc.), S1S28 (Xixian Haitang, etc.), S1S51 (Hebei Pingdinghaitang), S1S3 (Xiangyangcun Daguo, etc.), S2S3 (Zhaiyehaitang, etc.), S3S51 (Xishan 1), S3S28 (Huangselihaerde, etc.), S2S28 (Honghaitang, etc.), S4S28 (Bo 11), S7S28 (Jiuquan Shaguo), S10Se (Dongchengguan 13), S10S21 (Dongxiangjiao) and SeS51 (Xiongyue Haitang). Simultaneously, the frequency of the S gene in the tested materials was analyzed. The findings revealed that different S genes had varying frequencies in Malus resources, as well as varying frequencies between intraspecific and interspecific. S3 had the highest frequency of 68.18%, followed by S1 (42.04%). In addition, the phylogenetic tree and origin evolution analysis revealed that the S gene differentiation was completed prior to the formation of various apple species, that cultivated species also evolved new S genes, and that the S50 gene is the oldest S allele in Malus plants. The S1, S29, and S33 genes in apple-cultivated species, on the other hand, may have originated in M. sieversii, M. hupehensis, and M. kansuensis, respectively. In addition to M. sieversii, M. kansuensis and M. sikkimensis may have also played a role in the origin and evolution of some Chinese apples.

BackgroundLarge-scale trials of multidomain interventions show that modifying lifestyle and psychological risk factors can slow cognitive decline. We aim to determine if a lower intensity, personally tailored secondary dementia prevention programme for older people with subjective or mild objective memory decline, informed by behaviour change theory, reduces cognitive decline over 2 years.MethodsA multi-site, single-blind randomised controlled trial recruiting 704 older adults at high dementia risk due to mild cognitive impairment (MCI) or subjective cognitive decline (SCD). Participants are randomised using 1:1 allocation ratio to the APPLE Tree intervention versus control arm (dementia prevention information), stratified by site. The intervention explores and implements strategies to promote healthy lifestyle, increase pleasurable activities and social connections and improve long-term condition self-management. Two facilitators trained and supervised by a clinical psychologist deliver ten, 1-h group video call sessions over 6 months (approximately every fortnight), video-call 'tea breaks' (less structured, facilitated social sessions) in intervening weeks and individual goal-setting phone calls every 2 weeks. From 6 to 12 months, participants meet monthly for 'tea breaks', with those not attending receiving monthly goal-setting phone calls. Participants receive a food delivery, pedometer and website access to cognitive training and information about lifestyle modification. Follow-ups for all outcome measures are at 12 and 24 months. The primary outcome is cognition (Neuropsychological Test Battery (NTB) score) at 24 months. Secondary outcomes are quality of life, cost per quality-adjusted life year (QALY) and wellbeing and lifestyle factors the intervention targets (diet, vascular risk, body weight, activity, sleep, anxiety, depression, social networks and loneliness, alcohol intake and smoking). Participants from purposively selected sites participate in qualitative process evaluation interviews, which will be analysed using thematic analytic methods.DiscussionIf effective, the intervention design, involving remote delivery and non-clinical facilitators, would facilitate intervention roll-out to older people with memory concerns.Trial registrationISRCTN17325135 . Registration date 27 November 2019.

The temporary immersion system bioreactor named GreenTray® presents advantages over the existing ones. Firstly, there is no need to use forceps to move the shoots or plantlets in or out of the recipient, nor is the use of a scalpel necessary to divide them. Secondly, the basis of the shoot can remain in the GreenTray® and can sprout again over several cycles of growth. These two characteristics reduce the costs in the process of micropropagation. In addition, shoot or plantlet development is enhanced by the aeration of the recipient, thus enriching the recipient's atmospheric CO2. This article describes and provides images and values of interest in (1) the micropropagation process of some commercial Prunus or Pyrus rootstocks; (2) the plantlet growth under autotrophic conditions; and (3) the inoculation of plants with pathogens that reproduce in vitro the symptoms observed in vivo, using the GreenTray® bioreactor. [ABSTRACT FROM AUTHOR]

Summary: Biosynthesis of flavonoid aglycones and glycosides is well established. However, key genes involved in their catabolism are poorly understood, even though the products of hydrolysis and oxidation play important roles in plant resistance to biotic stress.Here, we report on catabolism of dihydrochalcones (DHCs), the most abundant flavonoids in domesticated apple and wild Malus. Two key genes, BGLU13.1 and PPO05, were identified by activity‐directed protein purification. BGLU13.1‐A hydrolyzed phlorizin, (the most abundant DHC in domesticated apple) to produce phloretin which was then oxidized by PPO05. The process differed in some wild Malus, where trilobatin (a positional isomer of phlorizin) was mainly oxidized by PPO05.The effects of DHC catabolism on apple resistance to biotic stresses was investigated using transgenic plants. Either directly or indirectly, phlorizin hydrolysis affected resistance to the phytophagous pest two‐spotted spider mite, while oxidation of trilobatin was involved in resistance to the biotrophic fungus Podosphaera leucotricha. DHC catabolism did not affect apple resistance to necrotrophic pathogens Valsa mali and Erwinia amylovara.These results suggest that different DHC catabolism pathways play different roles in apple resistance to biotic stresses. The role of DHC catabolism on apple resistance appeared closely related to the mode of invasion/damage used by pathogen/pest. [ABSTRACT FROM AUTHOR]

To determine and compare the content of biochemical compounds in fruits of nine cultivars of M. domestica Borkh. and ten of Malus spp. (given in the research materials), to select the most promising for use in further breeding and recommend for use in various directions, considering the biochemical complex of characters, taste, and marketable qualities of fruits. The dry matter content, a sum of sugars, titratable acids, tannins, and ascorbic acid was evaluated for two years according to generally accepted operating methods. The large-fruited apple cultivars were found to have values of dry matter (11.2-22.8%) and small-fruited (15.5-30.9%); the total amount of sugars in large-fruited cultivars varies from 6.7 to 10.9%, in small-fruited from 7.5 to 12.7%; the amount of ascorbic acid in fruits of M. domestica fruits averaged from 6.0 to 12.2 mg.100 g-1, in crabapple from 6.6 to 22.8 mg.100 g-1; titratable organic acids in fruits of large cultivars ranged from 0.74 to 1.67%, in small ones from 1.50 to 2.34%; tannins content was found in the range from 0.06 to 0.52% in highfruited cultivars and from 0.29 to 2.61% in lower-fruited ones. Comparative evaluation of the biochemical composition of fruits between large-fruited and small-fruited species and cultivars of apple trees showed that representatives of Malus spp. are more promising for use in breeding and industrial purposes. The dynamics of the decrease of dry soluble substance's weight and the increase of ascorbic acid content in apple tree fruits were also noted. [ABSTRACT FROM AUTHOR]

AbstractMalus × adstringens Zabel ‘Hopa’ is an important crabapple cultivar with significant ornamental value. Here, we assembled its complete chloroplast (cp) genome using the next-generation sequencing technology to clarify the phylogenetic relationships in Malus. The total length of the complete chloroplast genome was 160,230 base pairs (bp) with a GC content of 36.50%, consisting of a large single-copy (LSC) region with a sequence length of 88,310 bp, a small single-copy (SSC) region with a sequence length of 19,196 bp, and a pair of inverted repeat (IR) regions of 26,362 bp. The complete chloroplast genome contained 128 genes, namely 84 protein-coding genes, 36 tRNA genes, and 8 rRNA genes. In addition, 73 SSRs were found in the M. ‘Hopa’ cp genome. The phylogenetic relationship of M. ‘Hopa’ in Malus is closely related to M. spectabilis (Aiton) Borkh. and then to M. sieversii (Lebed.) M. Roem. Our results demonstrate that it is feasible to resolve the phylogenetic relationships of crabapple cultivars and identify their putative maternal lineages using cp genomic data.

Pollen carries extensive genetic information, which may provide clues regarding the kinship of Malus, whose genetic relationships are complex. In this study, the phenotypic variation of pollen from 107 Malus taxa was investigated using combined methods of intraspecific/interspecific uniformity testing, cluster analysis, and Pearson correlation analysis. The family aggregation distributions in Malus sections, species, and cultivars were analyzed to infer their pedigree relationships. The results showed that (1) compared with pollen size and morphology, aberrant pollen rate and ornamentation were highly interspecifically differentiated, but ornamentation was also intraspecifically unstable, especially perforation densities (c.v.¯ > 15%). (2) The pollen alteration direction from the original to the evolutionary population of Malus was large to small, with elliptic to rectangular morphologies, large and compact to small and sparse ridges, and low to high perforation densities. However, there was no significant change in pollen size. (3) The 107 studied taxa were divided into four groups. Malus species were relatively clustered in the same section, while homologous cultivars showed evidence of family aggregation distribution characteristics (92.60% of cultivars were clustered with their parents). (4) M. baccata and M. pumilar var. neidzwetzkyana were high-frequency parents, participating in 38.7% and 20.7% of cross-breeding, respectively. Overall, this study provides a reference for identifying Malus’ pedigree relationship.

Malus × adstringens Zabel 'Hopa' is an important crabapple cultivar with significant ornamental value. Here, we assembled its complete chloroplast (cp) genome using the next-generation sequencing technology to clarify the phylogenetic relationships in Malus. The total length of the complete chloroplast genome was 160,230 base pairs (bp) with a GC content of 36.50%, consisting of a large single-copy (LSC) region with a sequence length of 88,310 bp, a small single-copy (SSC) region with a sequence length of 19,196 bp, and a pair of inverted repeat (IR) regions of 26,362 bp. The complete chloroplast genome contained 128 genes, namely 84 protein-coding genes, 36 tRNA genes, and 8 rRNA genes. In addition, 73 SSRs were found in the M. 'Hopa' cp genome. The phylogenetic relationship of M. 'Hopa' in Malus is closely related to M. spectabilis (Aiton) Borkh. and then to M. sieversii (Lebed.) M. Roem. Our results demonstrate that it is feasible to resolve the phylogenetic relationships of crabapple cultivars and identify their putative maternal lineages using cp genomic data. [ABSTRACT FROM AUTHOR]

SUMMARY: Dihydrochalcones (DHCs) including phlorizin (phloretin 2′‐O‐glucoside) and its positional isomer trilobatin (phloretin 4′‐O‐glucoside) are the most abundant phenylpropanoids in apple (Malus spp.). Transcriptional regulation of DHC production is poorly understood despite their importance in insect‐ and pathogen‐plant interactions in human physiology research and in pharmaceuticals. In this study, segregation in hybrid populations and bulked segregant analysis showed that the synthesis of phlorizin and trilobatin in Malus leaves are both single‐gene‐controlled traits. Promoter sequences of PGT1 and PGT2, two glycosyltransferase genes involved in DHC glycoside synthesis, were shown to discriminate Malus with different DHC glycoside patterns. Differential PGT1 and PGT2 promoter activities determined DHC glycoside accumulation patterns between genotypes. Two transcription factors containing MYB‐like DNA‐binding domains were then shown to control DHC glycoside patterns in different tissues, with PRR2L mainly expressed in leaf, fruit, flower, stem, and seed while MYB8L mainly expressed in stem and root. Further hybridizations between specific genotypes demonstrated an absolute requirement for DHC glycoside production in Malus during seed development which explains why no Malus spp. with a null DHC chemotype have been reported. [ABSTRACT FROM AUTHOR]

Pantoea vagans C9-1 (C9-1) is a biological control bacterium that is applied to apple and pear trees during bloom for suppression of fire blight, caused by Erwinia amylovora. Strain C9-1 has three megaplasmids: pPagl, pPag2, and pPag3. Prior bioinformatic studies predicted these megaplasmids have a role in environmental fitness and/or biocontrol efficacy. Plasmid pPag3 is part of the large Pantoea plasmid (LPP-1) group that is present in all Pantoea spp. and has been hypothesized to contribute to environmental colonization and persistence, while pPag2 is less common. We assessed fitness of C9-1 derivatives cured of pPag2 and/or pPag3 on pear and apple flowers and fruit in experimental orchards. We also assessed the ability of a C9-1 derivative lacking pPag3 to reduce populations of E. amylovora on flowers and disease incidence. Previously, we determined that tolerance to stresses imposed in vitro was compromised in derivatives of C9-1 lacking pPag2 and/or pPag3; however, in this study, the loss of pPag2 and/or pPag3 did not consistently reduce the fitness of C9-1 on flowers in orchards. Over the summer, pPag3 contributed to survival of C9-1 on developing apple and pear fruit in two of five trials, whereas loss of pPag2 did not significantly affect survival of C9-1. We also found that loss of pPag3 did not affect C9-1's ability to reduce E. amylovora populations or fire blight incidence on apple flowers. Our findings partially support prior hypotheses that LPP-1 in Pantoea species contributes to persistence on plant surfaces but questions whether LPP-1 facilitates host colonization. [ABSTRACT FROM AUTHOR]

To determine and compare the content of biochemical compounds in fruits of nine cultivars of M. domestica Borkh. and ten of Malus spp. (given in the research materials), to select the most promising for use in further breeding and recommend for use in various directions, considering the biochemical complex of characters, taste, and marketable qualities of fruits. The dry matter content, a sum of sugars, titratable acids, tannins, and ascorbic acid was evaluated for two years according to generally accepted operating methods. The large-fruited apple cultivars were found to have values of dry matter (11.2-22.8%) and small-fruited (15.5-30.9%); the total amount of sugars in large-fruited cultivars varies from 6.7 to 10.9%, in small-fruited from 7.5 to 12.7%; the amount of ascorbic acid in fruits of M. domestica fruits averaged from 6.0 to 12.2 mg.100 g-1, in crabapple from 6.6 to 22.8 mg.100 g-1; titratable organic acids in fruits of large cultivars ranged from 0.74 to 1.67%, in small ones from 1.50 to 2.34%; tannins content was found in the range from 0.06 to 0.52% in high-fruited cultivars and from 0.29 to 2.61% in lower-fruited ones. Comparative evaluation of the biochemical composition of fruits between large-fruited and small-fruited species and cultivars of apple trees showed that representatives of Malus spp. are more promising for use in breeding and industrial purposes. The dynamics of the decrease of dry soluble substance's weight and the increase of ascorbic acid content in apple tree fruits were also noted.

A collection of 30 Phytophthora cactorum and 12 P. pseudotsugae (subclade 1a) strains isolated from several recent surveys across California was phylogenetically compared to a worldwide collection of 112 conspecific strains using sequences from three barcoding loci. The surveys baited P. cactorum from soil and water across a wide variety of forested ecosystems with a geographic range of more than 1000 km. Two cosmopolitan lineages were identified within the widespread P. cactorum, one being mainly associated with strawberry production and the other more closely associated with apple orchards, oaks and ornamental trees. Two other well-sampled P. cactorum lineages, including one that dominated Californian restoration outplantings, were only found in the western United States, while a third was only found in Japan. Coastal California forest isolates of both Phytophthora species exhibited considerable diversity, suggesting both may be indigenous to the state. Many isolates with sequence accessions deposited as P. cactorum were determined to be P. hedraiandra and P. ×serendipita, with one hybrid lineage appearing relatively common across Europe and Asia. This study contains the first report of P. pseudotsugae from the state of California and one of the only reports of that species since its original description.

Introduction: The expression of miR408 is affected by copper (Cu) conditions and positively regulates anthocyanin biosynthesis in Arabidopsis. However, the underlying mechanisms by which miR408 regulates anthocyanin biosynthesis mediated by Cu homeostasis and reactive oxygen species (ROS) homeostasis remain unclear in Malus plants. Objectives: Our study aims to elucidate how miR408a and its target, basic blue protein (BBP) regulate Cu homeostasis and ROS homeostasis, and anthocyanin biosynthesis in Malus plants. Methods: The roles of miR408a and its target BBP in regulating anthocyanin biosynthesis, Cu homeostasis, and ROS homeostasis were mainly identified in Malus plants. Results: We found that the BBP protein interacted with the copper-binding proteins LAC3 (laccase) and CSD1 (Cu/Zn SOD superoxide dismutase), indicating a potential crosstalk between Cu homeostasis and ROS homeostasis might be mediated by miR408 to regulate the anthocyanin accumulation. Further studies showed that overexpressing miR408a or suppressing BBP transiently significantly increased the expression of genes related to Cu binding and Cu transport, leading to anthocyanin accumulation under light induction in apple fruit and Malus plantlets. Consistently, opposite results were obtained when repressing miR408a or overexpressing BBP. Moreover, light induction significantly increased the expression of miR408a, CSD1, and LAC3, but significantly reduced the BBP expression, resulting in increased Cu content and anthocyanin accumulation. Furthermore, excessive Cu significantly increased the anthocyanin accumulation, accompanied by reduced expression of miR408a and Cu transport genes, and upregulated expression of Cu binding proteins including BBP, LAC3, and CSD1 to maintain the Cu homeostasis and ROS homeostasis in Malus plantlets. Conclusion: Our findings provide new insights into the mechanism by which the miR408a-BBP-LAC3/CSD1 module perceives light and Cu signals regulating Cu and ROS homeostasis, ultimately affecting anthocyanin biosynthesis in Malus plants.

High pressure assisted infusion of nutrients into food was in situ monitored with magnetic resonance imaging (MRI). Modification of an off-the-shelf pressure reactor with an MRI detection circuit provided a large enough volume to accommodate food. The model food used here was peeled apple flesh as it is considered as a good mimic for fibrous food. The nuclear spin relaxation properties of the water surrounding the apple flesh were enhanced by adding paramagnetic manganese cations. In this way, MRI relaxation contrast can be used to monitor the location of doped bulk water in and around the apple flesh during pressurization. This work tracked the efficiency of pressure induced nutrient infusion in situ, demonstrating that pressure gating and ramping offer no nutrient mass transport advantage over operation at constant pressure and that the presence of a peel expectedly disrupts solute transport into the fruit. High pressure assisted infusion, with all pressurization strategies shown here, yielded nearly 100-fold faster infusion times than at ambient pressure.

The present study evaluates the phytotoxic effects of phloretin, a prevalent secondary metabolite of apple trees, on the broadleaf weed Capsella bursa-pastoris (L.) Medik. known for its resistant myxospermous seeds that form a long-lasting soil bank. The results indicate a significant, dose-dependent inhibitory effect of phloretin on the growth and morphological parameters of weed seedlings grown in vitro. Although the applied phloretin concentrations (250–1000 µM) were not lethal to the C. bursa-pastoris seedlings after two weeks, the metabolism of the seedlings was impaired, resulting in an accumulation of lipid droplets in the root tips and root hairs. Histochemical analysis shows deposits of phenols in the root epidermal cells, which are probably aggregates of phloretin or its metabolic derivatives. The accumulation of pectin in the cell walls of root border cells in phloretin-treated seedlings indicates an attempt to reduce the uptake of phloretin and reduce its concentration in the cells. Inhibition of shoot growth associated with chlorosis and reduced photosynthetic pigment content is a consequence of seedling exposure to phloretin. This study provides a basis for further evaluation of phloretin as a new bioherbicidal compound and for elucidating the mechanism underlying its phytotoxic activity.

The most important task of the present time for botanical gardens is the assessment of collections of living plants with the subsequent introduction of the positive results of the introduction of new species, forms and varieties of plants into the practice of urban gardening and urban floristics. Collections published in our country at different times on wild and useful species, as well as on rare species successfully introduced in different countries in botanical gardens, show what a rich and promising assortment of ornamental tree and shrub plants we have. All that remains is to introduce the new promising range of ornamental species developed over the years through various nurseries into organizations involved in the design and specific landscaping of the modern urban environment, especially in large cities of the country.

Significance Statement: We present a high‐quality, haplotype‐resolved, chromosome‐scale genome assembly and annotation for Malus fusca, a wild relative of the commercial apple. This genomic resource is an important contribution to the field of plant genomics and has significant implications for the development of new apple cultivars with enhanced disease and stress resistance. [ABSTRACT FROM AUTHOR]

Flavor is a major component of the apple eating experience, along with taste, texture and appearance. Apples produce a wide array of volatile organic compounds that impart particular flavors. Cultivars producing increased or novel flavors may have more desirability for consumers and help to differentiate the fruit. Efficiently breeding more flavorful apples requires understanding the volatiles present in apple germplasm and their potential sensory impact. As an initial step towards the development of more flavorful apple cultivars, a New Zealand collection of germplasm was surveyed, and seventy-three volatiles were identified as being present in at least half the accessions. Substantial differences in the presence and relative abundance of specific volatiles were uncovered across the accessions and could sometimes be linked to an apple's flavor profile. The large number of volatiles analyzed allowed relationships between and among molecule classes to be established. Esters were found to be the main drivers of volatile differentiation across accessions. Apples tended to produce either ethyl or acetate esters, suggesting there is different genetic control for these two ester types. Additionally, esters generally had larger broad-sense heritabilities, indicating they could be easier targets for modifying apple flavor. This volatile dataset is a valuable resource for apple breeding, and increases the understanding of an important consumer trait. [ABSTRACT FROM AUTHOR]

Glomerella leaf spot (GLS), caused by the fungal pathogen Colletotrichum fructicola, significantly threatens apple production. Some resistances to plant disease are mediated by the accumulation of nucleotide‐binding site and leucine‐rich repeat (NBS‐LRR) proteins that are encoded by a major class of plant disease resistance genes (R genes). However, the R genes that confer resistance to GLS in apple remain largely unclear. Malus hupehensis YT521‐B homology domain‐containing protein 2 (MhYTP2) was identified as an N6‐methyladenosine RNA methylation (m6A) modified RNA reader in our previous study. However, whether MhYTP2 binds to mRNAs without m6A RNA modifications remains unknown. In this study, we discovered that MhYTP2 exerts both m6A‐dependent and ‐independent functions by analysing previously obtained RNA immunoprecipitation sequencing results. The overexpression of MhYTP2 significantly reduced the resistance of apple to GLS and down‐regulated the transcript levels of some R genes whose transcripts do not contain m6A modifications. Further analysis indicated that MhYTP2 binds to and reduces the stability of MdRGA2L mRNA. MdRGA2L positively regulates resistance to GLS by activating salicylic acid signalling. Our findings revealed that MhYTP2 plays an essential role in the regulation of resistance to GLS and identified a promising R gene, MdRGA2L, for use in developing apple cultivars with GLS resistance. [ABSTRACT FROM AUTHOR]

[Display omitted] • A crosstalk between copper homeostasis and ROS homeostasis mediated by the miR408a-BBP-LAC3/CSD1 module was revealed under light induction and copper stress in Malus plants. • The copper homeostasis fluctuation triggers ROS homeostasis variation and participates in modulating anthocyanin accumulationin under excessive copper and copper defficiency in Malus plants. The expression of miR408 is affected by copper (Cu) conditions and positively regulates anthocyanin biosynthesis in Arabidopsis. However, the underlying mechanisms by which miR408 regulates anthocyanin biosynthesis mediated by Cu homeostasis and reactive oxygen species (ROS) homeostasis remain unclear in Malus plants. Our study aims to elucidate how miR408a and its target, basic blue protein (BBP) regulate Cu homeostasis and ROS homeostasis, and anthocyanin biosynthesis in Malus plants. The roles of miR408a and its target BBP in regulating anthocyanin biosynthesis, Cu homeostasis, and ROS homeostasis were mainly identified in Malus plants. We found that the BBP protein interacted with the copper-binding proteins LAC3 (laccase) and CSD1 (Cu/Zn SOD superoxide dismutase), indicating a potential crosstalk between Cu homeostasis and ROS homeostasis might be mediated by miR408 to regulate the anthocyanin accumulation. Further studies showed that overexpressing miR408a or suppressing BBP transiently significantly increased the expression of genes related to Cu binding and Cu transport, leading to anthocyanin accumulation under light induction in apple fruit and Malus plantlets. Consistently, opposite results were obtained when repressing miR408a or overexpressing BBP. Moreover, light induction significantly increased the expression of miR408a , CSD1 , and LAC3 , but significantly reduced the BBP expression, resulting in increased Cu content and anthocyanin accumulation. Furthermore, excessive Cu significantly increased the anthocyanin accumulation, accompanied by reduced expression of miR408a and Cu transport genes, and upregulated expression of Cu binding proteins including BBP , LAC3 , and CSD1 to maintain the Cu homeostasis and ROS homeostasis in Malus plantlets. Our findings provide new insights into the mechanism by which the miR408a-BBP-LAC3/CSD1 module perceives light and Cu signals regulating Cu and ROS homeostasis, ultimately affecting anthocyanin biosynthesis in Malus plants. [ABSTRACT FROM AUTHOR]

Trihelix transcription factors are involved in the growth and development of plants, as well as various stress responses. In the study presented, we identified 37 trihelix family genes in the apple genome (MdTH). The trihelix genes were located on 13 chromosomes. Phylogenetic analysis of these MdTH and the trihelix genes of other species divided them into six subfamilies: GT-1, GT-2, SH4, SIP1, GTγ, and GTδ. The genes of different groups significantly diverged in their gene structure and conserved functional domains. Cis-element analysis showed that promoter sequences of MdTH genes contained light response elements, phytohormone response elements, and stress-related cis-elements. The expression pattern analysis results demonstrated that MdTH were regulated by drought, salinity, as well as high and low temperatures. MdTH4 and MdTH24 were highly regulated by soil salinity, MdTH4—by drought. MdTH30 showed high expression under low temperature; MdTH8, MdTH20, and MdTH36—under high temperature. [ABSTRACT FROM AUTHOR]

Herein, a novel visual method for detecting triazophos based on competitive bio-barcode immunoassay was described. The competitive immunoassay was established by gold nanoparticles (AuNPs), magnetic microparticle (MMPs) and triazophos, combined with biochip hybridization system to detect the residual of triazophos in water and apple. Because AuNPs carried many bio-barcodes, which hybridized with labeled DNA on the biochip, catalyzed signal amplification using silver staining was detected by grayscale values as well as the naked eye. Notably, the grayscale values decreases with increasing the concentrations of triazophos, and the color change weakened gradually. The detection range was in between 0.05 and 10 ng/mL and the minimum detection limit was set at 0.04 ng/mL. Percent recovery calculated from spiked water and apple samples ranged between 55.4 and 107.8% with relative standard deviations (RSDs) of 12.4-24.9%. It has therefore been shown that this protocol provides a new insight for rapid detection of small molecule pesticides in various matrices.

Sugars and auxin have important effects on almost all phases of plant life cycle, which are so fundamental to plants and regulate similar processes. However, little is known about the effect of cross-talk between glucose and indole-3-acetic acid (IAA) on growth and development of apple trees. To examine the potential roles of glucose and IAA in root architecture, root nitrogen (N) metabolism and photosynthetic capacity in 'Hanfu' (Malus domestica), a total of five treatments was established: single application of glucose, IAA, and auxin polar transport inhibitor (2, 3, 5-triiodobenzoic acid, TIBA), combined application of glucose with TIBA and that of glucose with IAA. The combined application of glucose with IAA improved root topology system and endogenous IAA content by altering the mRNA levels of several genes involved in root growth, auxin transport and biosynthesis. Moreover, the increased N metabolism enzyme activities and levels of genes expression related to N in roots may suggest higher rates of transformation of nitrate (NO3 - -N) into amino acids application of glucose and IAA. Contrarily, single application of TIBA decreased the expression levels of auxin transport gene, hindered root growth and decreased endogenous IAA content. Glucose combined with TIBA application effectively attenuated TIBA-induced reductions in root topology structure, photosynthesis and N metabolism activity, and mRNA expression levels involved in auxin biosynthesis and transport. Taken together, glucose application probably changes the expression level of auxin synthesis and transport genes, and induce the allocation of endogenous IAA in root, and thus improves root architecture and N metabolism of root in soil with deficit carbon. [ABSTRACT FROM AUTHOR]

Malus florentina is reported as new to the Bulgarian dendroflora. The species was found on the border of two floristic regions, occurring at an altitude from 600 to 900 m in both: Western Frontier Mts. (Vlahina Mts.) and the Valley of Struma River (Northern). The closest known natural localities are in North Macedonia, Serbia and Kosovo, and in the European part of Turkey. About 55 individuals have been recorded as a result of а fast preliminary inventory and about one-quarter of them were flowering and setting fruits. Although the actual size and status of the population of M. florentina in the region still have to be evaluated, immediate measures for its conservation should be taken. [ABSTRACT FROM AUTHOR]

Purpose: Soil compaction inhibits root growth by limiting ethylene diffusion and often occurs in apple orchards. This study explored the mechanism of ethylene accumulation around apple roots in compacted soil from a microbial perspective, as well as its effects on root architecture, to improve root growth. Methods: One-year-old potted apple (Malus domestica Borkh 'Red Fuji') trees whose rootstocks were Malus hupehensis (Mh) and Malus robusta (Mr) were used as materials. After maintaining soil compaction for one year, the root growth, root ethylene, and ethylene-modulating bacteria were detected, and correlation analysis was performed. This work isolated rhizosphere ACC deaminase-producing bacteria (ADPB), inoculated ADPB with Mh seedlings, and then measured ACC and ethylene contents, root growth, and acdS and efe copies. Results: Soil compaction changed root architecture, decreased root activity, and inhibited root growth in both Mh and Mr. In addition, soil compaction enhanced root ACC and ethylene contents and reduced the acdS/efe ratio. Pearson's correlation analysis indicated that rhizosphere ADPB was significantly correlated with ethylene production and root growth. After the inoculation of ADPB with Mh seedlings in compacted soil, the number of acdS copies and the acdS/efe ratio were increased, the root ACC and ethylene contents were decreased, and root growth was improved. Conclusion: The ACC content in compacted soil was a decisive precursor of ethylene production in apple roots. Inoculating ADPB improved the root growth of Mh in compacted soil by down-regulating ACC and ethylene contents and recovering the ratio of acdS/efe, thereby alleviating compaction stress on apple roots. [ABSTRACT FROM AUTHOR]

Docynia has been treated as a separate genus or merged into Cydonia or Docyniopsis. Our phylogenomic evidence from 797 single-copy nuclear genes and plastomes confirmed the sister relationship between Docynia and Docyniopsis. By integrating the phylogenomic and morphological evidence, we propose to accept a broad generic concept of Malus and merge Docynia into Malus. Three new combinations are also made here: Malus delavayi (Franch.) B.B.Liu, M. indica (Wall.) B.B.Liu and M. longiunguis (Q.Luo & J.L.Liu) B.B.Liu. [ABSTRACT FROM AUTHOR]

Black canker, caused by fungi of the genus Diplodia, poses an increasing threat to pome fruit production in Germany. In order to determine the spread of the disease in Germany, 423 bark samples with suspicious symptoms from all federal states were examined in a non-representative monitoring. In 62% of the samples examined, fungi of the genus Diplodia were isolated, with the species D. bulgarica dominating the Diplodia species spectrum with 56.6%, followed by D. seriata with 28.3%. D. malorum (7.8%), D. mutila (4.9%), D. juglandis (1.6%) and D. intermedia (0.8%), on the other hand, took up only a small part of the Diplodia species spectrum, with the latter two species being first records on apple in Germany. [ABSTRACT FROM AUTHOR]

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Abstract Background Volatile components are important secondary metabolites essential to fruit aroma quality, thus, in the past decades many studies have been extensively performed in clarifying fruit aroma formation. However, aroma components and biosynthesis in the fruit of Binzi (Malus pumila × Malus asiatica), an old local species with attractive aroma remain unknown. Results We investigated two Binzi cultivars, ‘Xiangbinzi’ (here named high-fragrant Binzi, ‘HFBZ’) and ‘Hulabin’ (here named low-fragrant Binzi, ‘LFBZ’) by monitoring the variation of volatiles and their precursors by Gas Chromatography–Mass Spectrometer (GC–MS), as well as their related genes by RNA-seq during post-harvest ripening. We firstly confirmed that ‘HFBZ’ and ‘LFBZ’ fruit showed respiratory climacteric by detecting respiratory rate and ethylene emission during post-harvest; found that esters were the major aroma components in ‘HFBZ’ fruit, and hexyl 2-methylbutyrate was responsible for the ‘fruity’ note and most potent aroma component, followed by ethyl acetate, ethyl butanoate, (E)-2-hexenal, and 1-hexanol. Regarding aroma synthesis, fatty acid metabolism seemed to be more important than amino acid metabolism for aroma synthesis in ‘HFBZ’ fruit. Based on RNA-seq and quantitative reverse transcription PCR (RT-qPCR), LOX2a, LOX5a, ADH1, and AAT1 genes are pointed to the LOX pathway, which may play a vital role in the aroma formation of ‘HFBZ’ fruit. Conclusion Our study firstly investigated the aroma components and related genes of Binzi fruit, and provided an insight into the fragrant nature of Malus species.

Introduction: Multi-walled nanotubes (MWCNTs) consist of multiple rolled layers of graphene. Nitrogen plays an important role in apple growth. The effect of MWCNTs on nitrogen utilization in apple needs to be further investigated. Methods: In this study, the woody plant Malus hupehensis seedlings were used as plant materials, the distribution of MWCNTs in the roots was observed, and the effects of MWCNTs on the accumulation, distribution, and assimilation of nitrate by the seedlings were explored. Results: The results showed that MWCNTs could penetrate the roots of Malus hupehensis seedlings, and the 50, 100, and 200 µg-mL-1 MWCNTs significantly promoted the root growth of seedlings, increased root number, root activity, fresh weight, and nitrate content of seedlings, and also increased nitrate reductase activity, free amino acid, and soluble protein content of roots and leaves. 15N tracer experiments indicated that MWCNTs decreased the distribution ratio of 15N-KNO3 in Malus hupehensis roots but increased its distribution ratio in stems and leaves. MWCNTs improved the utilization ratio of 15N-KNO3 in Malus hupehensis seedlings, with the values being increased by 16.19%, 53.04%, and 86.44% following the 50,100, and 200 µg-mL-1 MWCNTs, respectively. The RT-qPCR analysis showed that MWCNTs significantly affected the expression of genes (MhNRTs) related to nitrate uptake and transport in roots and leaves, and MhNRT1.4, MhNRT1.7, MhNRT1.8, MhNRT2.1, MhNRT2.5, and MhNRT2.7 were notably up-regulated in response to 200 µg-mL-1 MWCNTs. Raman analysis and transmission electron microscopy images indicated that MWCNTs could enter the root tissue of Malus hupehensis and were distributed between the cell wall and cytoplasmic membrane. Pearson correlation analysis showed that root tip number, root fractal dimension, and root activity were the main factors affecting root uptake and assimilation of nitrate. Conclusions: These findings suggest that MWCNTs promoted root growth by entering the root, stimulated the expression of MhNRTs, and increased NR activity, thereby enhancing the uptake, distribution, and assimilation of nitrate by root, and ultimately improved the utilization of 15N-KNO3 by Malus hupehensis seedlings. [ABSTRACT FROM AUTHOR]

Apple blotch (AB) is a major disease of apple in Asia and recently emerged in Europe and the United States. It is caused by the fungus Diplocarpon coronariae (formerly Marssonina coronaria; teleomorph: Diplocarpon mali) and leads to severe defoliation of apple trees in late summer, resulting in reduced yield and fruit quality. To develop effective disease management strategies, a sound knowledge of the pathogen's biology is crucial. Data on the early phase of disease development are scarce: No data on spore dispersal in Europe are available. We developed a highly sensitive TaqMan qPCR method to quantify D. coronariae conidia in spore trap samples. We monitored temporal and spatial dispersal of conidia of D. coronariae and the progress of AB in spring and early summer in an extensively managed apple orchard in Switzerland in 2019 and 2020. Our results show that D. coronariae overwinters in leaf litter, and spore dispersal and primary infections occur in late April and early May. We provide the first results describing early-season dispersal of conidia of D. coronariae, which, combined with the observed disease progress, helps to understand the disease dynamics and will be a basis for improved disease forecast models. Using the new qPCR method, we detected D. coronariae in buds, on bark, and on fruit mummies, suggesting that several apple tissues might serve as overwintering habitats for the fungus, in addition to fallen leaves. [ABSTRACT FROM AUTHOR]

Der Schwarze Rindenbrand, der von Pilzen aus der Gattung Diplodia hervorgerufen wird, stellt eine zunehmende Bedrohung für den Kernobstanbau in Deutschland dar. Um die Verbreitung der Erkrankung im Bundesgebiet zu ermitteln, wurden in einem nicht repräsentativen Monitoring 423 Rindenproben mit verdächtigen Symptomen aus allen Bundesländern untersucht. In 62 % der untersuchten Proben waren Pilze aus der Gattung Diplodia zu isolieren, wobei die Art D. bulgarica mit 56,6 %, gefolgt von D. seriata mit 28,3 % das Diplodia-Artenspektrum dominiert haben. D. malorum (7,8 %), D. mutila (4,9 %), D. juglandis (1,6 %) und D. intermedia (0,8 %) traten dagegen relativ selten auf, wobei die beiden letztgenannten Arten Erstnachweise an Apfel in Deutschland sind.

A ‘Duquesa’ é produto de cruzamento realizado na Universidade de Cornell – EUA, em 1977, entre a cultivar israelense Anna (mãe), portadora de baixa exigência em frio hibernal (< 250h), e a seleção americana D1R100T147 (pai), portadora de alta resistência à sarna. As sementes foram introduzidas em Santa Catarina no final daquele ano. Em 1984 foi selecionada a M-44 (inicialmente Malus 44) pela sua produtividade, baixa exigência em frio hibernal, alta resistência à sarna. Testes conduzidos na Estação Experimental de Caçador/ Epagri, e na Estação Experimental Agronômica de Eldorado do Sul – UFRGS, RS, mostraram bom desempenho desta nova cultivar em produtividade, adaptação climática em climas de invernos amenos e, ainda, resistência à sarna. Isto motivou seu lançamento como nova cultivar sob a denominação de Duquesa.

A EPAGRI 408-Condessa é produto de hibridação controlada efetuada em 1987 na Epagri/Estação Experimental de Caçador, SC, entre as cultivares Gala (mãe) e M-41 (pai) (Figura 1). A partir de uma população de 1.456 plântulas, em 1989 foram selecionadas 93 plântulas em termos de adaptação climática e fitossanidade. Estas 93 seleções preliminares foram enxertadas sobre o porta-enxerto anão M-9 para acelerar a frutificação e avaliar a qualidade dos frutos. Nos ciclos de 1991, 1992 e 1993 foram selecionadas 17 dentre as 93, as quais foram enxertadas sobre o porta-enxerto M-7 e avaliadas em nível de coleções em Caçador e em Fraiburgo, SC.

Visando reduzir o tempo de produção da muda de macieira, testou-se a possibilidade de se enxertar a cultivar copa sobre estacas lenhosas não enraizadas de Marubakaido, levando--as logo após ao viveiro, promovendo-se a cicatrização do enxerto e o enraizamento da estaca simultaneamente.