Apple Species Research Articles

Overexpression of a protein kinase gene MpSnRK2.10 from Malus prunifolia confers tolerance to drought stress in transgenic Arabidopsis thaliana and apple

Members of the sucrose non-fermenting-1-related protein kinase 2 (SnRK2) family play central roles in the abscisic acid (ABA) signaling pathway and in mediating osmotic stress signaling and tolerance in plants. Previously, 12 full-length coding sequences that belong to SnRK2 gene family were identified and cloned in wild apple species Malus prunifolia. In this study, one of the members, MpSnRK2.10, was overexpressed in Arabidopsis and apple to investigate its potential function in response to drought stress. The results showed that overexpression of this gene did not affect plant growth under normal conditions. However, the transgenic plants showed enhanced tolerance to drought, as indicated by the amelioration in phenotype appearance and physiological indices related to drought stress damage. Additionally, transgenic apple plants overexpressing MpSnRK2.10 exhibited greater sensitivity to ABA compared to wild-type (WT) plants. Moreover, expressions of three stress response genes, MdRAB18, MdRD22, and MdRD29B, were more strongly induced in transgenic apple plants than in the WT when subjected to ABA and mannitol treatments. Taken as a whole, our study suggests that MpSnRK2.10 has a role in the enhancement of ABA signal transduction in response to stress, and that the manipulation of MpSnRK2.10 expression could be a feasible approach for improving abiotic stress tolerance in apple and other important crops.

Use of steady-state imaging setup for assessing the internal optical properties of non-spherical apple samples

The aim of this paper was to retrieve the absorption (µa) and reduced scattering (µ's) coefficients of whole apples which exhibit a complex shape. The effect of the local boundary curvature on the retrieved optical properties was investigated by means of numerical simulations and measurements carried out at the wavelength of 633 nm. A first attempt was made by performing Monte Carlo simulations on an apple-like spheroid model covered with a thin skin layer of thickness 80 µm. Monte Carlo data were then analyzed to depict the changes of photon densities, diffusively reflected images and optical properties as a function of the light source location over the surface of such target. Second, spatially-resolved backscattered images were acquired from 207 ‘Royal Gala’, and the values of µa and µ's were retrieved using an inverse algorithm to fit the scattering profiles with a diffusion theory model, in a selected fitting range of 2.8–10 mm. The results confirm the theoretical prediction and show that the absorption coefficient µa may be overestimated, while the reduced scattering coefficient µ's is slowly changed when the measurements are performed on these apple species. Finally, experiments carried out on 200 apples still show that µ's is negatively correlated to the fruit firmness with a correlation coefficient (r) of 0.63. The spatially-resolved technique provides an efficient means for measuring the optical properties of fruits, and may be also useful for assessing the apple firmness.

Agrilus mali Matsumara (Coleoptera: Buprestidae), a new invasive pest of wild apple in western China: DNA barcoding and life cycle.

Agrilus mali Matsumara (Coleoptera: Buprestidae) is a wood‐boring beetle distributed to eastern China that occasionally injures apple species. However, this wood‐boring beetle is new to the wild apple forests (Malus sieversii) of the Tianshan Mountains (western China) and has caused extensive tree mortality. The development of a biological control program for these wild apple forests is a high priority that requires exploration of the life cycle, DNA barcoding and taxonomic status of A. mali. In this study, to determine the diversity of invasive beetles, a fragment of the mitochondrial cytochrome oxidase gene was analyzed. Based on the results, beetles from Gongliu and Xinyuan counties of Xinjiang were identical but differed from those in the apple nursery of Gongliu by a single‐nucleotide substitution. We summarize the taxonomic status, relationships, and genetic distances of A. mali among other Agrilus species using the Tajima‐Nei model in maximum likelihood phylogeny. Analysis revealed that A. mali was closely related to Agrilus mendax and both belong to the Sinuatiagrulus subgenus. The life cycle of A. mali was investigated based on a monthly regular inspection in the wild apple forests of Tianshan. Similar to congeneric species, hosts are injured by larvae of A. mali feeding on phloem tissue, resulting in serpentine galleries constructed between bark and xylem that prevent nutrient transport and leading to tree mortality. Future studies will focus on plant physiological responses to the invasive beetles and include surveys of natural enemies for a potential classical biological control program.

Recent Advances in Temperate Fruit Crop Improvement

Globally India is the second largest producer of fruits; however the productivity is significantly low as compared to advanced countries. The majority of the temperate fruits and nuts are being cultivated in the north-western Himalayan and small areas are lies in north eastern parts. High altitude and temperate regions are capable to produce good quality fruits. But the foothill where the chilling is insufficient adversely affects the yield and quality. In India, majority of the temperate fruits were introduced from other parts of the world and some are indigenous to India like walnuts and wild apple species. Therefore, the improvement of the temperate fruits and nuts were taken place mainly through introduction of promising cultivars. The exotic cultivars are still the backbone of fruit production in India particularly for apple, pear, peach, plum and cherry. Promising varieties were introduced from USA, UK, Germany, Italy, France, Australia, New Zealand, Hungary and Bulgaria and were evaluated for commercial exploitation. However, in walnutand almonds, production is mainly from Indigenous cultivars/ local land races. These consisted of non-descriptive trees and highly variable in yield and quality traits. Recently, several varieties have been developed in India in apple, peach, plum, apricot, cherry and walnut. The potential of these varieties are immense for commercial exploitation. The paper attempt to document the accomplishment made in temperate fruit and nut improvement in perspective to Indian Scenario. The information is valuable for breeders and academician for further studies.

Apple nursery trees and irrigation water as potential external inoculum sources of apple replant disease in South Africa

Apple replant disease (ARD) is a biological phenomenon caused by soilborne agents that include selected species of fungi (Rhizoctonia and ‘Cylindrocarpon’-like), oomycetes (Pythium, Phytopythium and Phytophthora) and nematodes (Pratylenchus). Old orchard soils previously planted to apple or related species are a primary inoculum source of ARD pathogens. In the current study, nursery trees and irrigation water were investigated as potential external ARD inoculum sources in South Africa. Investigations conducted at five nurseries over two years revealed that roots of nursery trees were infested by several ARD agents. In the 2013 sampling year, Pythium irregulare and Pythium ultimum were obtained from trees in five and two of the nurseries, respectively, using isolation studies. Based on isolation studies conducted on individual trees in 2013, 47% and 4% of all surveyed trees contained P. irregulare and P. ultimum, respectively. In the 2014 season, real-time quantitative PCR (qPCR) analyses of root tissue from individual trees demonstrated that all of the nurseries and 95% of trees contained P. irregulare, whereas three nurseries and 41% of trees contained P. utlimum. The only other oomycete pathogens that were detected in nursery tree roots were Pythium spp. complex B2A and Pythium sylvaticum and each only occurred in one nursery in one of the sampling years. For all nurseries in both years, trees were consistently infected with ‘Cylindrocarpon’-like spp. Pratylenchus spp., which were only analysed in 2013, was present in all five nurseries and in 29% of the trees. Infestation levels were high, with 22% of trees having Pratylenchus root densities that exceeded 100 per 5 g of roots. Pythium irregulare was the dominant oomycete pathogen detected in irrigation water samples (31% to 76% of the samples) obtained from 13 orchards over two years on a monthly basis. The ARD pathogens P. ultimum, Phytopythium litorale and Pythium spp. complex B2A were rarely identified in irrigation water, along with five other non-pathogenic Pythium and Phytopythium species. The association of ARD causative agents with nursery trees and irrigation water suggests that these could function as potential ARD inoculum sources that might limit post-plant tree growth.

Invisible apple snail invasions: importance of continued vigilance and rigorous taxonomic assessments.

Due to the similarities of overall shell morphology among apple snail species and considerable variability within species, substantial taxonomic confusion has plagued the accurate identification of Pomacea species. Many invasive apple snails have been mistakenly identified as P. canaliculata since their introduction to Asia around 1980. In 2008, three other introduced species in addition to P. canaliculata were recognized. In 2013, a fifth, previously unrecognized lineage was reported from China, indicating that despite the taxonomic clarity brought by previous work, continued surveys and taxonomic research are necessary to prevent additional introductions and continued spread, as well as to develop effective management strategies. Phylogenetic analysis of mitochondrial COI sequences confirmed the presence of a widespread unidentified Pomacea lineage in China. All sequences from samples of this newly documented lineage were recovered in a monophyletic clade delineated from closely related species; however, different DNA barcoding methods yielded inconsistent species boundaries. Additionally, nuclear EF1α sequences indicated incomplete lineage sorting or recent hybridization of the unidentified lineage with the other two established species. Barcoding is a valuable tool for species discovery, and a powerful approach for delineating introduced species. However, determining the identity of the newly discovered invasive lineage in China will require an integrated taxonomic approach incorporating individuals from the native range, and examination of natural history collections at museums around the world. To manage and prevent additional spread of already established species, and to stop the introduction of new taxa, continued monitoring and rigorous taxonomic assessments must be undertaken. © 2018 Society of Chemical Industry.

Выявление новых комплексных источников устойчивости к болезням яблони с использованием молекулярных методов в Беларуси

In order to identify new complex sources of resistance to apple diseases, a hybrid fund, created in 1994-2007 – 22 364 plants of one year, obtained from 252 crossing combinations and selections in the breeding plot – 4936 plants was analyzed. 120 selections were evaluated in the primary test orchards on rootstocks 62-396 and PB-4, of which 12 promising hybrids were identified. DNA preparations were extracted from fresh apple-tree leaves using the Genomic DNA Purification Kit (Thermo scientific, EC) kit. Markers: OPL19, AD13-SCAR, OPB12 STS, VfC1 and VfC2, AL07-SCAR and AM19-SCAR, Vf2ARD, were used to identify the scab resistance genes Rvi2, Rvi4, Rvi5, Rvi6, Rvi17 and for identification of powdery mildew resistance genes Pl1, Pl2, Pl-w, Pl-d are the markers OPU02 SCAR, OPAT20450, EM M02, EM DM01. The presence of the dominant allele of the Rvi6 gene in the homozygous state ( VfVf ) was established in three hybrids: 94-13/39, 99-39/76 and 2007-18/19, in the heterozygous ( Vfvf ) – in six hybrids and cv. Diyament. Comparison of the results of DNA analysis and experimental field data of resistance to scab and powdery mildew allowed to obtain reliable results on the presence of resistance genes in the 12 apple genomes studied, obtained as a result of targeted hybridization of the original forms – derivatives of various apple species. New sources with complex resistance to scab and powdery mildew – carriers of several resistance genes in one genotype have been identified: 2000-45/70 ( Rvi2, Rvi4, Rvi5, Rvi6 Pl-d ), 94-13/39 ( Rvi2, Rvi5, Rvi6 ), 2007-19/15 ( Rvi2, Rvi6 Rvi17, Pl-d ).

Studying the polymorphism of the gene MDP0000151428 among the varieties and species of apples

Aim. The aim of this work was to study the variability of the gene MDP0000151428, which belongs to the DREB family, among varieties of different genetic origin, which have different resistance to cold. Methods. Polymorphism was analyzed by PCR and sequencing. Results. Cloning and sequencing of the gene MDP0000151428 from 18 varieties and species of apple with different levels of resistance to cold have been carried out. An assessment of the variability of its primary structure showed the presence of point mutations. Most of them were single nucleotide substitutions, in one case a single nucleotide deletion was observed. The degree of sequence identity ranged from 97.5 % to 100 %. Conclusions. Evaluation of polymorphism of gene length MDP0000151428 showed that it is quite conservative and does not carry extended insertions or deletions in 20 varieties and species of apple trees with different levels of resistance to cold. The analysis showed that the frequency of occurrence of mutations in different sites of the gene MDP0000151428 differs. The nucleotides in 138, 341 and 472 positions are most susceptible to mutations. Comparison of hypothetical amino acid sequences showed the presence of separate substitutions. Most often they occur in 114 and 158 positions.
 Keywords: apple tree, gene MDP0000151428, transcription factors, resistance to cold.

Distribution of bacteriosis in- duced by Erwinia amylovora in various types of plants of Polissya biocenosis under condition of pathogen contamination by bacteriophage

The study results of the spread of bacterial disease induced by Erwinia amylovora, which is the carrier of bacteriophages on pears, quince, hawthorn, hazel and other types of plants in the environment in different climatic regions of Polissya. Based on the survey a detailed assessment of the affected plant habitus, based on their growth and development during the growing season is presented. At the same time, plants, leaves, branches, fruits and root system were analyzed for the detection of pathogens. It was investigated that blackening of leaves and drying of tops and lateral branches in pears, apple and stone species of plants are the main symptoms of fireblight. Characteristically, the middle tier of plants is often affected by pathogens in a mixed complex infection. This complex infectious and pathological process is especially evident in recent years under conditions of warming up the climate. Microbiological, virological and environmental methods were used in the work. It is important that new opportunities for the accumulation of phages are opened on the basis of taking into account the development of bacterial disease in various plant species, which are common in forest ecosystems, parks, reserves and agrocenoses. Such studies, in our opinion, create the preconditions for the discovery of plant-reservoirs of bacteria and its phages in combination with phytovirused, microscopic fungi. Taking into account the considerable spread of fireblight in plants, an important task today in the agro-industrial complex is to use stable varieties of crops against the pathogen of this disease.

Morphometrics Reveals Complex and Heritable Apple Leaf Shapes.

Apple (Malus spp.) is a widely grown and valuable fruit crop. Leaf shape is important for flowering in apple and may also be an early indicator for other agriculturally valuable traits. We examined 9,000 leaves from 869 unique apple accessions using linear measurements and comprehensive morphometric techniques. We identified allometric variation as the result of differing length-to-width aspect ratios between accessions and species of apple. The allometric variation was due to variation in the width of the leaf blade, not the length. Aspect ratio was highly correlated with the first principal component (PC1) of morphometric variation quantified using elliptical Fourier descriptors (EFDs) and persistent homology (PH). While the primary source of variation was aspect ratio, subsequent PCs corresponded to complex shape variation not captured by linear measurements. After linking the morphometric information with over 122,000 genome-wide single nucleotide polymorphisms (SNPs), we found high SNP heritability values even at later PCs, indicating that comprehensive morphometrics can capture complex, heritable phenotypes. Thus, techniques such as EFDs and PH are capturing heritable biological variation that would be missed using linear measurements alone.

First Report of Colletotrichum fructicola Causing Anthracnose on Camellia sinensis in Guangdong Province, China

Colletotrichum Corda is one of the most important plant pathogens that has a wide range of hosts including apple (Velho et al. 2016), coffee (Prihastuti et al. 2009), and many other species of plants. Meanwhile, anthracnose on tea plants (Camellia sinensis) caused by Colletotrichum spp. is one of the most severe diseases. During 2014 and 2015, a leaf and twig blight occurred with a disease incidence of 20 to 40% on tea plants in growing regions of Jiaoling County, in Guangdong Province. Symptoms began as small, water-soaked lesions on young leaves, and later became larger, semicircular or irregular, dark brown, reddish-brown at the margin. At later stages, the lesions became grayish white with black acervuli on surface. Six Colletotrichum-like isolates were isolated from symptomatic leaves on PDA, and pure cultures were obtained by single-spore isolation. All isolates initially produced white fluffy aerial hyphae and turned dark grayish with bright orange conidial masses. Ascomata 109.2 to 252.6 × 97.1 to...

Iron deficiency stress can induce MxNAS1 protein expression to facilitate iron redistribution in Malus xiaojinensis.

Iron (Fe) is a vital trace element in plants, and deficiency of this element in apple trees can reduce fruit quality. Nicotianamine (NA) is known to play an important role in Fe transport and endogenous hormone balance. In the present study, we investigated the role of a nicotianamine synthase 1 gene (MxNas1) in an apple species, Malus xiaojinensis, that has a more Fe-efficient genotype than other apple species and ecotypes. To characterise the response of M.xiaojinensis to Fe deficiency, we used quantitative Q-PCR to determine the level of expression of MxNas1 and Western blot to measure protein levels. Immunohistochemical staining and GFP fluorescence localisation of the MxNAS1 protein were also carried out. HPLC and polarised absorption spectrophotometry were performed to investigate the effects of overexpression of MxNas1 in order to elucidate the role of MxNAS1 in the cellular uptake of active Fe in tobacco suspension cells. We found that MxNas1 expression and protein levels were higher under Fe deficiency stress than under Fe sufficiency. Immunohistochemical staining showed that MxNAS1 was localised mainly in the epidermal and vascular tissues of the roots, vascular tissues of the stem and palisade cells of mature leaves, and in parenchyma cells of young leaves. MxNAS1 was mainly localised in the plasma membranes and vesicles of protoplasts. In addition, overexpression of MxNas1 in stable transgenic tobacco cells increased NA and active Fe content under Fe sufficiency. The results suggest that MxNas1 expression in M.xiaojinensis is induced in response to Fe deficiency stress, resulting in higher levels of the protein. MxNAS1 may be involved in the redistribution of Fe in M.xiaojinensis under Fe deficiency.

Fire Blight Resistance in Wild Accessions ofMalus sieversii

Fire blight (Erwinia amylovora) is a devastating bacterial disease in apple that results in severe economic losses. Epidemics are becoming more common as susceptible cultivars and rootstocks are being planted, and control is becoming more difficult as antibiotic-resistant strains develop. Resistant germplasm currently being utilized by breeding programs tend to have small fruit size and poor flavor characteristics. Malus sieversii, a progenitor species of domestic apple, is notable for its relatively large, palatable fruit and some accessions have been reported to be resistant to fire blight. In this study, nearly 200 accessions of M. sieversii and appropriate controls were inoculated with E. amylovora in both Washington and West Virginia to identify fire blight resistant accessions. Twelve accessions were identified with resistance comparable to highly resistant and resistant controls. Several accessions exhibited a unique resistance response, not previously reported in domestic apple (M. × domestica), characterized by low incidence of infection but high severity once infection was initiated. Several of these M. sieversii accessions will be used as parents in future crosses in the Washington State University apple breeding program.

Reduced representation genome sequencing reveals patterns of genetic diversity and selection in apple.

Identifying DNA sequence variations is a fundamental step towards deciphering the genetic basis of traits of interest. Here, a total of 20 cultivated and 10 wild apples were genotyped using specific-locus amplified fragment sequencing, and 39,635 single nucleotide polymorphisms with no missing genotypes and evenly distributed along the genome were selected to investigate patterns of genome-wide genetic variations between cultivated and wild apples. Overall, wild apples displayed higher levels of genetic diversity than cultivated apples. Linkage disequilibrium (LD) decays were observed quite rapidly in cultivated and wild apples, with an r2 -value below 0.2 at 440 and 280 bp, respectively. Moreover, bidirectional gene flow and different distribution patterns of LD blocks were detected between domesticated and wild apples. Most LD blocks unique to cultivated apples were located within QTL regions controlling fruit quality, thus suggesting that fruit quality had probably undergone selection during apple domestication. The genome of the earliest cultivated apple in China, Nai, was highly similar to that of Malus sieversii, and contained a small portion of genetic material from other wild apple species. This suggested that introgression could have been an important driving force during initial domestication of apple. These findings will facilitate future breeding and genetic dissection of complex traits in apple.

Development of a near infrared calibration model with temperature compensation using common temperature-difference spectra for determining the Brix value of intact fruits

In order to create a calibration model with temperature compensation, the calibration method using the partial least squares regression based on the combined spectra measured at some different temperatures is promising. However, the method is time-consuming since it requires spectra acquisition at different temperatures. In addition, the sample quality may change during the period for the different temperature adjustment of samples. The spectra of the target fruit species of peaches, pears, and persimmons were measured at 25℃ using the interactance method. Spectra for 20℃ and 30℃ were created artificially using temperature-difference second derivative spectra from the 25℃-second derivative spectra. Then, the possibility of temperature-difference second derivative spectra of fruit(s) to create the correct 20℃ and 30℃ artificial second derivative spectra was evaluated. The temperature-difference second derivative spectra created from each target fruit species could be useful for each target fruit species while the common temperature-difference second derivative spectra created from the three target fruit species were useful for not only each target fruit species but also the other fruit species of apples. The calibration model for apples developed using the common temperature-difference second derivative spectra showed low standard error of performance and bias of 0.45°Brix and 0.09°Brix, respectively. The model could be applied well to the prediction sets of apples at 20℃, 25℃, and 30℃ with non-significant biases.

Fire blight resistance of Malus ×arnoldiana is controlled by a quantitative trait locus located at the distal end of linkage group 12

Erwinia amylovora is the pathogen which incites fire blight - the most devastating bacterial disease affecting pome fruit production worldwide. So far, only one functionally proven gene for resistance to this disease has been reported in Malus, even though several quantitative trait loci (QTLs) have been identified. Since some highly aggressive strains are capable of overcoming described resistances in Malus, including that of the only isolated and functionally-proven resistance gene, it is important to identify more resistance donors useful for the establishment of pyramided and durable resistance. Quantitative trait locus analyses were performed on F1 progenies derived from a cross between the Malus ×domestica cultivar, Idared, and the wild apple species M. ×arnoldiana. Progenies were artificially inoculated with two strains of E. amylovora – the moderately aggressive strain Ea222_JKI, and the highly aggressive Canadian strain, Ea3049. A QTL was identified at the distal end of linkage group (LG) 12 of M. ×arnoldiana explaining over 50% of the phenotypic variation among the progenies inoculated with Ea222_JKI. A significant QTL effect was also identified on LG12 using the phenotypic data of the progenies inoculated with Ea3049. The fire blight resistance QTL of M. ×arnoldiana (FB_Mar12) appeared to be located at a similar position as those of Evereste and/or M. floribunda clone 821 below the SSR marker Hi07f01 on LG12 of the apple genome. The results presented here suggest that this QTL could be allelic with the other reported fire blight QTLs on LG12. Nevertheless, it is imperative to perform more studies aimed at further elucidating the resistance mechanism of this wild apple species since it displays a significant resistance effect to Ea3049.

A Study on Nutritional Composition and Value Addition of Crab Apple ( Malus baccata )

Apple cultivation is main occupation of farmers in dry and high hills of Himachal Pradesh but this species of crab apple (Malus baccata) is grown wildly in the state but due to their smaller size, improper shape, poor colour, the fruit could not fetch good market value and gone as waste. By considering these parameters of the fruit, the study was conducted to evaluate nutritive composition and to develop food products i.e. fruit bar/ gelatinized layers and apple jam from highly nutritious underutilized fruit. The fruit contain high amounts of vitamin C content (17.13 mg/100g) and pectin content (5.57 % as calcium pectate). The nutritive composition in crab apple based fruit bar/ gelatinized layers and jam were studied during storage interval of 9 months. The results for fruit bar/ gelatinized layers shows that the TSS (0B), pH, ascorbic acid(mg/100g), total and non-reducing sugars (%) decreased from 750B – 74.370B, 3.06-2.96, 5.27-5.05, 64.67-62.49 and 8.26 – 5.32, respectively while acidity and reducing sugars(%) increased from 1.20 -1.37 and 55.98 -58.60 with the increase of storage intervals. Similar trend was observed for crab apple jam during storage interval. The prepared products viz., fruit bar/gelatinized layers and apple jam was subjected for sensory evaluation to a panel of members at different storage intervals i.e. (fresh, 3, 6 and 9 months of storage period) and the products were found as acceptable in terms of colour, taste, consistency/texture even up to storage interval of 9 months at ambient conditions.

Transcriptome Analysis and Identification of Genes Associated with Floral Transition and Flower Development in Sugar Apple (Annona squamosa L.).

Sugar apple (Annona squamosa L.) is a semi-deciduous subtropical tree that progressively sheds its leaves in the spring. However, little information is available on the mechanism involved in flower developmental pattern. To gain a global perspective on the floral transition and flower development of sugar apple, cDNA libraries were prepared independently from inflorescent meristem and three flowering stages. Illumina sequencing generated 107,197,488 high quality reads that were assembled into 71,948 unigenes, with an average sequence length of 825.40 bp. Among the unigenes, various transcription factor families involved in floral transition and flower development were elucidated. Furthermore, a Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis revealed that unigenes exhibiting differential expressions were involved in various phytohormone signal transduction events and circadian rhythms. In addition, 147 unigenes exhibiting sequence similarities to known flowering-related genes from other plants were differentially expressed during flower development. The expression patterns of 20 selected genes were validated using quantitative-PCR. The expression data presented in our study is the most comprehensive dataset available for sugar apple so far and will serve as a resource for investigating the genetics of the flowering process in sugar apple and other Annona species.

Effect of Silicon Application on Silicon Contents in “Fuji” Apple in Loess Plateau

ABSTRACTThis study investigated silicon (Si) fertilizer application in an apple orchard; Si fertilizers were applied at rates of 50 and 100 g/tree, with humic acid and citric acid, respectively. The results showed that Si accumulation in apple tree was influenced by the type and amount of fertilizer, and was higher in organic Si treatment. Si content in leaves, peel, flesh and whole fruit significantly increased with increasing rates of Si application, especially in a high amount of organic treatment. This study indicates that the source of Si fertilizer and the rate of Si applications are important factors influencing the uptake of Si by “Fuji” apple tree, which is a widely cultivated apple species in Loess Plateau in China.

Possible Impact of Climate Change on the Quality of Apples from the Major Producing Areas of China

Meteorological conditions are important environmental factors affecting apple quality. To understand the possible impact of climate change on the apple quality of the major producing areas in China and assess the quality of major apple species (e.g., Fuji, Ralls, and Golden Delicious), we studied the variation trends and abrupt change characteristics of six major climate factors affecting seven physicochemical indices of apple quality across five apple regions, including the Loess Plateau, Bohai Bay, the Old Course of the Yellow River, Southwest Highlands, and Xinjiang, using statistical methods, meteorological indices, and the ArcGIS analysis tool based on the meteorological observational data from 1961 to 2013. The results show that the spatial and temporal distributions of annual average temperature, annual sunshine duration, average summer temperature, summer diurnal temperature range, and average summer relative humidity all significantly changed (except annual precipitation) and that abrupt changes occurred. The annual temperatures and average summer temperatures in the Loess Plateau apple region and the Liaoning producing region of Bohai Bay increased within optimal ranges. In addition, for high-value regions, the hours of sunshine decreased, helping to improve the fruit shape index, sugar-acid ratio, and vitamin C (VC) content. Relatively high temperatures continued to increase to high values which remained lower than the optimal upper limit; the diurnal temperature range continued to decrease; and the sunshine hours significantly decreased within the optimal range, which might have worsened fruit hardness, soluble sugar, and peel anthocyanin in the producing regions of Southwest Shandong of Bohai Bay, Southeast Hebei of the Old Course of the Yellow River, Northern Anhui, and Jiangsu. In the production regions of the Yun-Gui plateau in the Southwest highlands, increased summer temperature and the diurnal temperature range were both within the optimal ranges, which might have helped to reduce fruit hardness and increase soluble sugar content. However, continuously increased temperature and reduced sunshine might have worsened the apple shape index and fruit coloring. In the Xinjiang apple-producing region, the climate became warmer and more humid with reduced daily sunshine hours, which might have improved the exterior quality of apples and reduced fruit hardness. Thus, the climate changes over the last 50 years have positively affected the seven apple quality physicochemical properties in the Loess Plateau and Xinjiang, whereas the impacts on the different indices of apple quality in the other apple-producing regions are less coherent. In general, climate change has significantly affected the apple quality of the major production regions in China. Corresponding scientific measures are needed to assure high apple quality to increase the income of farmers in the future.