Apple Species Research Articles

Last updates on cell death point, bud death time and exothermic characteristics of flower buds for deciduous fruit species by using differential thermal analysis

The fine details of freezing behavior in flower buds during deacclimation and their exothermic characteristics are poorly understood with the use of differential thermal analysis (DTA). Understanding how spring frosts affect cold tolerance of flower buds is a fundamental question in deciduous fruit species and will be useful in developing cold-tolerant varieties and species. The occurrence of cell death point (CDP), bud death time (BDT) and exothermic characteristics in apple (Malus domestica L. 'Golden Delicious'), pear (Pyrus communis L. 'Santa Maria'), quince (Cydonia oblonga L. a native wild 'Type- 24'), sour cherry (Prunus cerasus L. 'Kütahya'), wild apricot (Prunus armeniaca L. 'Zerdali-24'), nectarine (Prunus persica var. nectarine L. 'Armking'), peach (Prunus persica L. 'Loring'), plum (Prunus salicina L. 'Formosa') and cherry (Prunus avium L. 'native wild type') flower buds in pink-white bloom and at the full bloom stages were determined using DTA. During controlled freezing of flower buds in deciduous fruit species one distinct freezing events (single exothermic peak) was detected by DTA, and it was considered the cell death point of the flower buds. The fruit species were classified as most (sour cherry, peach, quince and cherry), moderately hardy (apple and pear) and least hardy (wild apricot, plum and nectarine) according to tolerance to low temperatures. The highest mean BDT values of flower buds were observed in pear and nectarine species compared to other species. The flower buds of nectarine and pear species showed large and wider single exothermic peaks compared to quince, sour cherry, wild apricot, plum, apple, cherry and peach species. The single exotherms in the flower buds of the fruit species support the hypothesis that supercooling in buds is lost mainly starting with bud swell and usually spreads rapid ice nucleation into the flower buds due to established xylem continuity between the woody tissues and the bud scales. This hypothesis, however, reflects the complexity of the freezing process in flower buds, and so indicates that comprehensive observational studies are essential to understanding freezing tolerance traits in deciduous fruit species, after and during budbreak.

Molecular Genetic Identification of Apple Cultivars Based on Microsatellite DNA Analysis. I.\xa0The Database of 600 Validated Profiles

Apple (Malus × domestica Borkh.) is the most widely grown permanent fruit crop of temperate climates. Although commercial apple growing is based on a small number of globally spread cultivars, its diversity is much larger and there are estimates about the existence of more than 10,000 documented varieties. The varietal diversity can be described and determined based on phenotypic characters of the external and internal traits of fruit, which, however, can be modulated by environmental factors. Consequently, molecular methods have become an important alternative means for the characterisation of apple cultivar diversity. In order to use multilocus microsatellite data for determination of unidentified or misidentified apple varieties, a database with molecular genetic fingerprints of well-determined reference cultivars needs to be available. The objective of the present work was to establish such a database that could be applied for the molecular genetic determination of a large number of historic and modern, diploid and triploid apple cultivars. Based on the analysis of more than 1600 accessions of apple trees sampled in 37 public and private cultivar collections in different European countries at 14 variable microsatellite loci, a database with 600 molecular genetic profiles was finally obtained. The key criterion for considering a molecular genetic profile as confirmed and for including it into the reference database was that at least two accessions of the same cultivar of different provenances generated an identical result, which was achieved for 98% of the apple cultivars present in the database. For the remaining genotypes, the cultivar assignment was supported by a parentage analysis or by comparison to molecular genetic profiles available in published works. The database is composed of 574 scion cultivars, 24 rootstock genotypes and two species of crab apples. Of the 574 scion cultivars, 61% were derived from historic or old cultivars, many of which were grown in Central Europe in the past. The remaining scion cultivars are currently grown or available in testing programmes and may gain importance in the future. In order to validate the genotyping data, parentage analysis was performed involving cultivars and rootstocks that arose after 1900, for which information about at least one parent cultivar was available from pomological and scientific literature and the molecular genetic profiles of the assumed parent(s) were also present in our database. This analysis revealed the presence of null alleles at locus COL, however, when excluding this locus, a mean genotyping error rate of only 0.28% per locus was revealed, which points to a high reliability of the dataset. The datasets with 14 and 13 loci (excluding locus COL) showed a high degree of discrimination power, with a combined non-exclusion probability of identity of 2.6 × 10−20 and 3.4 × 10−19. Five of the microsatellite loci analysed in the present study overlapped with another published dataset and after the application of conversion values, it was possible to align the allele lengths and compare the molecular genetic profiles of 20 randomly derived cultivars, which were analysed in both studies. This comparison evidenced an exact correspondence of the microsatellite profiles contained in the two datasets, further pointing to the accuracy of our database. Apart from its application to characterise genetic resources or to manage germplasm collections, the here presented database could serve as an important tool for quality control or as a useful instrument in breeding programmes.

New Approaches on Measurement of Fruit Firmness For Fresh-Cut Products

Due to the heavy working conditions of the business world in today's conditions, changes have occurred in the habits of people consuming fruits and vegetables. It is also a fact that the people working in economically developed societies spend less time preparing food, eat at restaurants or take fast food home. Working individuals’ tendency to purchase fruits and vegetables peeled, even chopped, shredded or grated, that is semi-processed -ready for consumption- is getting stronger due to reasons such as foodservice industry, cost, labor, and hygiene. For this reason, the fresh-cut fruit and vegetable sector has become the food sector with a rapid growth trend in recent years. The biggest problem in these products is the short shelf life after semi-finished product preparation processes and the deterioration in product quality during the sales process. Preservative solutions developed to protect the product quality are successful, however, the effects of these applications on fruit firmness cannot be measured accurately due to the deterioration of fruit integrity (slicing, chopping, grating, etc.) during product processing. In this study, it has been aimed to accurately determine the changes in fruit firmness during the preservation process of the fruits taken into the fresh-cut process by using specially developed apparatus (45, 60, 90° angled V-blocks assembly). The fruit integrity deteriorates due to the preservation of the fruit by slicing the fruits taken into the fresh-cut process; after this stage, the firmness measurement cannot be carried out stably in the analyses to be made for the change of the fruit quality. The blocks apparatus developed for this purpose can be used in order to more accurately determine the effects of the applications made for quality preservation in the process of storage and shelf life in fruits divided into 4-6-8 slices. In the study, the values obtained from the firmness measurements made with sliced fruits in apple, pear and quince species showed that the developed angled blocks apparatus gave more stable measurement values considering the standard deviation value and the variation created by the averages.

Discovery of a stable vitamin C glycoside in crab apples (Malus sylvestris)

Non-targeted LC-MS metabolomics on fruit of three wild and domesticated apple species (Malus sylvestris, M. sieversii and M. domestica) showed that two crab apple (M. sylvestris) accessions were distinguished by high concentrations of an ascorbic acid glycoside (AAG). This was partly purified, but key NMR signals were masked by inseparable sucrose. Reference samples of 2-O-β-D-glucopyranosyl L-ascorbic acid and 2-O-β-D-galactopyranosyl L-ascorbic acid were synthesised, but both coincided with the crab apple AAG on LC-MS. Peracetylation of the crab apple extract allowed both purification and characterisation, and the AAG was proven to be 2-O-β-D-glucopyranosyl L-ascorbic acid by comparison of 1H NMR, HRMS and HPLC data with synthesised peracetylated ascorbyl glycoside standards. The stability of the natural AA 2-β-glycoside was similar to synthetic 2-O-α-D-glucopyranosyl L-ascorbic acid, used widely in cosmetic and pharmaceutical products. This discovery in crab apples (Rosaceae) is only the fourth reported occurrence of any ascorbyl glycoside from plants, the others being from Cucurbitaceae, Solanaceae and Brassicaceae. It is hypothesised that AAGs may be more widespread in plants than currently realised.

A Shallow Convolutional Neural Network for Apple Classification

In the automatic apple sorting task, it is necessary to automatically classify certain apple species. A shallow convolutional neural network (CNN) architecture is proposed for this purpose. After collecting a certain number of apple images and labelling them, training data is obtained through a series of data augmentation operations, and then training and parameter optimization are carried out through the Caffe framework. The feasibility of the method is verified by experiments which are divided into two cases. In the case of no occlusion, the classification accuracy of apple images reaches approximately 92% in our test set. Besides, block voting is used to aid the proposed method and a good result can be achieved in our test set in the case of part occlusion caused by branches and leaves, rotten spots, and other kinds of apples. The proposed shallow network is characterized by a small number of parameters and shows resistance to overfitting with a limited dataset. Such a network presents an alternative for classification related tasks in smart visual Internet of Things and brings attention to reducing the complexity of deep neural networks while maintaining their strength.

Things

Things brenda Lin (bio) My mother talks to me in fruits and vegetables. On Tuesdays, the first day of the week traditional wet markets are open in Taiwan, red-and-white striped plastic bags will appear in my house, couriered across town by my mother's faithful driver/gofer/handyman. The bags will be filled with all of my children's favorite foods. Because my husband is from San Diego, and because he is not Taiwanese, it constantly surprises and delights my mother when my children like foods that are very Taiwanese. The foods that she sends over include passion fruits with deep-hued purple skin, sent with handwritten notes reminding me to wait until the skin is puckered before consuming; small, soft guavas with an aroma so sweet and powerful, they perfume the entire house. Once, my mother observed the children clamoring for calamari rings at a family dinner, and ever since, if she finds freshly caught squid at the market, a bag of three or four will also appear, slick and glistening. If you hit it just so, the layer just underneath the translucent skin explodes into what looks like a million tiny stars. That's how you know the squid is still alive. Cucumbers are a staple, as are sweet potatoes and whatever leafy-green vegetables are in season—there is one called "A vegetable" in Taiwanese, which the children find hilarious, and will always ask instead for "B vegetable." On the days she doesn't go to the market, boxes of fancy-grade fruit will arrive—giant green grapes the size of plums shipped from Japan or a species of wax apples dubbed "Black King Kong," because its skin is a deep red, richer and darker than the rosy skin of its more plebeian cousins. If not boxes of fruit or intricately packaged Taiwanese tea or nougats or the latest [End Page 265] award-winning pineapple or moon cakes, there will be takeout containers of various sizes and half-drunk bottles of wine. Judging by the contents of those boxes, or the name of the hotel restaurant printed on the paper bags in which they were carried, I can often guess which friends my parents dined with the previous evening. ________ When I first started living on my own in New York City after college, I loved having an almost-empty refrigerator, stocked with only the essentials I needed for the next few days. A visiting friend once opened up my cupboards one after another and grimaced: "You have no snacks!" I like having just what I need. This was before I knew about Marie Kondo or minimalism; for me, it just felt natural and made sense. I have never liked complication or too much hassle. In fact, when too many things start piling up, my insides start squeezing tight and I feel a physical constriction. In Chinese, hassle is ma fan—a combination of the characters for numbness and irritation. That encapsulates how I physically feel when there are too many things around me. I've never named this feeling as anxiety, but I do think it's a form of it. ________ Lately, the things arriving daily at my house have become much more than just fruits and vegetables. My mother has been retired for twenty years now. The first several years of her retirement, she traveled to remote parts of China and Southeast Asia to add to her collection of children's textiles made by indigenous tribes. She published books on her collection, organized by category—a book on children's hats, a book on baby carriers, a book on purses, another book on baby bibs and collars. She learned about the process of cultivating cotton plants and silk from silkworms, studied the ways dyes were extracted from plants and flowers, observed the different embroidery techniques used in different tribes, translated their signs and symbols into stories. She gathered her collection and organized exhibitions with local museums in Taiwan. She did what I imagine I would do in retirement—all the things she always wanted to do but which the daily minutiae in the life of a working mother prevented. After the books...

The origins and evolutionary history of feral apples in southern Canada.

Feral populations of domesticated crops can establish through two nonmutually exclusive pathways: hybridization with native relatives and recruitment of and recombination between known cultivars. The extent and relative importance of these pathways is not known, especially for woody fruit crops. Here, we examined the evolutionary origins of feral populations of Malus domestica (domestic apple) in southern Canada using a population genetic analysis. We characterized genotypes of 578 putative feral apple trees and evaluated them in relation to genotypes of 156 commercial cultivars, 28 non-native, ornamental crabapples and 47 native Malus coronaria trees using 14 microsatellite markers. No feral trees were genetic admixtures between domestic and native Malus; however, a minority of trees were admixed with introduced ornamental Malus. Feral trees and commercial cultivars both occurred in two major genetic groups and seven subgroups distributed throughout all commercial growing regions. A total of 42 cultivars, both heritage and currently grown, occurred in probable parental pairs for feral trees, with nine heritage varieties accounting for 72% of parental assignments. We conclude that feral apples in southern Canada are not products of hybridization with native M.coronaria but we cannot exclude ornamental apple species as contributing to the naturalization process. Nonhybrid feral domestic apples have multiple origins, with a prominent signature of early heritage cultivars. These lineages have spread and coexist throughout Ontario, rather than being derived strictly from local sources.

Selective colorimetric detection of HgII using silver nanoparticles modified with Apple and Nigella Sativa seed extracts and β-Cyclodextrin

The surface modification of silver nanoparticles (AgNPs) with natural products could be environmentally friendly method of manufacturing provided that their inherent properties could be substantiated. Therefore, AgNPs were synthesized from AgNO3 using β-Cyclodextrin and seed extracts from Apple (Ap-AgNPs) and Nigella Sativa species (N-AgNPs). AgNPs thus prepared were incorporated as a colorimetric sensor for determining HgII ions and proved to be both selective and adequately sensitive in detecting mercuric ions. These nanoparticles are found to show a limit of detection (LOD) of 29.0 nM and 58.0 nM for Ap-AgNPs and N-AgNPs, respectively. The results demonstrate the higher sensitivity of Ap-AgNPs over N-AgNPs with maximum absorption causing a color shift to blue due to HgII ions and the resulted color change from yellow to pale yellow, even colorless upon addition of HgII in AgNPs solutions. The results validate the applicability of nanoparticles as a sensor with the potential for rapid and on-site detection of HgII ions.

Characterization of Fe deficiency induced RING finger family members in apple species

Iron (Fe) is a critical element for plants and Fe deficiency can cause adverse effects on their growth, development, yield and quality. RING finger family is a large group known for their role under abiotic stresses in plants. The main aim of this research work was to identify the RING finger family members that responded to Fe deficiency in apple species. Their genetic structure, molecular evolution, and expression levels were analyzed to study the underlying mechanism of RING finger genes under Fe deficiency stress. A total of 76 RING finger genes that responded to Fe deficiency were identified. Based on their structural characteristics and phylogenetic relationships, the identified genes were divided into four subfamilies: Group I, Group II, Group III and Group IV. Chromosomal localization demonstrated that the 76 RING finger genes were randomly distributed on 17 chromosomes. The genetic structure and amino-acid-motif encoded varied among different gene members. Fifteen pairs of RING finger genes were identified as segmental duplicated. Further, synteny analysis with Circos was performed to examine the evolutionary relationship between Malus domestica and other Rosaceae genomes. The results of qRT-PCR in Malus xiaojinensis showed expression levels of these genes under Fe deficiency, indicating that Fe deficiency could induce the expression of these genes, thus verifying the accuracy of transcriptome data. These results provided useful information about the evolutionary relationship of RING finger gene family, potentially important under Fe deficiency. Moreover, it will help to identify the function of these RING finger genes in future research.

Relative resistance of indigenous and exotic accessions of apple against woolly apple aphid (Eriosoma lanigerum)

Twelve apple accessions, belonging to six apple species were screened to ascertain the relative resistance against Woolly apple aphid (WAA), Eriosoma lanigerum (Hausmann). The experiment was conducted at ICARIndian Agricultural Research Institute Regional Station, Shimla, India (1900 m, 31°06’ 21.6’’N, 77°07’02.5’’E) during 2014–16. The screening was done by visual indexing technique of apple accessions based on mean infestation of WAA on a 0–4 rating scale. The mean infestation rating differed significantly among apple accessions and ranged from zero to 3.42. Three apple accessions were scored the lowest (zero) mean infestation rating, i.e. Northern spy, M. prunifolia var. Maruba Borkh. and M. prunifolia var. Ringo-Asami. The M. baccata (Kashmir) and M. pumila were scored the highest (3.42) mean infestation rating, a pair wise comparison using Kruskal-Wallis test shows a significantly higher mean infestation on apple accessions M. baccata (Dhak), M. baccata (Kashmir) and M. pumila compare to Northern spy, M. prunifolia var. Maruba and M. prunifolia var. ringo Asami.The present study gave an update of resistance screening of apple accessions against WAA by Kishore et al. (2006) and this data set may help in identifying resistance sources which may directly be used as rootstocks to combat the edaphic WAA problem in apple and the identified resistance sources could be utilized for developing improved apple accessions with durable resistance and improved quality traits of high yielding apple cultivars. Further studies are required to unravel the mechanism of resistance in resistant apple accessions against WAA.

Sequencing of a Wild Apple (Malus baccata) Genome Unravels the Differences Between Cultivated and Wild Apple Species Regarding Disease Resistance and Cold Tolerance.

Malus baccata is one of four wild apple species that can hybridize with the cultivated apple species (Malus domestica). It is widely used in high-latitude apple-producing areas as a rootstock and breeding resource because of its disease resistance, and cold tolerance. A lack of a reference genome has limited the application of M. baccata for apple breeding. We present a draft reference genome for M. baccata. The assembled sequence consisting of 665 Mb, with a scaffold N50 value of 452 kb, included transposable elements (413 Mb) and 46,114 high-quality protein-coding genes. According to a genetic map derived from 390 sibling lines, 72% of the assembly and 85% of the putative genes were anchored to 17 linkage groups. Many of the M. baccata genes under positive selection pressure were associated with plant–pathogen interaction pathways. We identified 2,345 Transcription factor-encoding genes in 58 families in the M. baccata genome. Genes related to disease defense and cold tolerance were also identified. A total of 462 putative nucleotide-binding site (NBS)-leucine-rich-repeat (LRR) genes, 177 Receptor-like kinase (RLK) and 51 receptor-like proteins (RLP) genes were identified in this genome assembly. The M. baccata genome contained 3978 cold-regulated genes, and 50% of these gene promoter containing DREB motif which can be induced by CBF gene. We herein present the first M. baccata genome assembly, which may be useful for exploring genetic variations in diverse apple germplasm, and for facilitating marker-assisted breeding of new apple cultivars exhibiting resistance to disease and cold stress.

Molecular cloning and functional characterization of apple U-box E3 ubiquitin ligase gene MdPUB29 reveals its involvement in salt tolerance

An E3 ubiquitin ligase gene (Genbank accession no.: MD01G1010900) was cloned from the Royal Gala apple genome (Malusxdomestica Borkh.). Sequence analysis showed that the length of the MdPUB29 gene was 1 275 bp, encoding 424 amino acids. Phylogenetic tree analysis indicated that the apple E3 ubiquitin ligase exhibited the greatest sequence similarity to Pyrus×bretschneideri. The predicted protein structural domain of MdPUB29 showed that it contained a U-box domain. qRT-PCR analysis showed that MdPUB29 was expressed widely in different tissues of the Royal Gala apple species, and was highly expressed in the root, while the expression of MdPUB29 was significantly inhibited by exogenous NaCl. Immunoblotting assays revealed that MdPUB29 protein abundance in tissue cultures of the Royal Gala apple accumulated under NaCl stress conditions. Three-dimensional protein structure prediction indicated that MdPUB29 was highly homologous with AtPUB29. The growing potential of MdPUB29-expressing apple calli and Arabidopsis were much stronger than that of the control under salt stress conditions, suggesting that MdPUB29 may positively regulate salt tolerance.

Genetic Diversity in Apple Accessions Belong to Different Species Collected from Natural Populations of Tianshan Mountains, South-West Kyrgyzstan

There isn’t any concrete consensus about the origin of domesticated apple. However, it is generally thought that the origin of this apple primarily comes from M. sieversii, also known as Central Asia wild apple. The second significant contribution is thought to be supplied by M. sylvestris. Central Asia is an important origin region for apples. Within this region, mountainous and forestlands of Kyrgyzstan constitute a significant source for wild apple species. The present study was conducted to put forth the genetic relationships between 65 accessions belonging to M. kirgishorum, M. domestica, M. niedzwetzkyana, and M. sieversii apple species collected from different regions of Kyrgyzstan and 12 accessions belonging to M. baccata, M. prunifolia, M. sylvestris and M. domestica species collected from different regions of Turkey. A combination of ISSR and SRAP markers were used in this study. About 71.1% polymorphism was obtained with ISSR primers and 83.5% with SRAP primers. Similarity level of accessions studied was found between 0.74 and 0.95. All materials used in this study were genetically separated from each other. The apple accessions used in this study were generally placed in a mixed fashion with the other materials in the dendrogram. Apart from some exceptions, standard apple accessions of M. domestica species taken from Kyrgyzstan and Turkey were grouped separately from standard apple cultivars. While the genotypes of wild species were mostly placed in the other group of the dendrogram, small number of genotypes of M. domestica species was placed in this group. Present outcomes revealed significant information for the preservation, assessment and breeding of wild apple species of Kyrgyzstan.

Biochemical analysis on selected fruits ofAnnonaspecies

The family Annonaceae comprises about 80 genera and 850 species occurring in the tropics, but with relics of earlier distributions remaining in some temperate regions. The large, edible, pulpy fruits typically called “annona” include species of Annona, custard apple (A. squamosa), soursop/graviola (A. muricata) and bullock's heart (A. reticulata) which are known to have excellent health and medicinal benefits which deserve to be further explored. They contain antioxidants, possess anti cardio-vascular, anti-obese, anti-diabetic, anti-cancer, anti-microbial activity and have a positive effect on blood haemoglobin. It is also efficacious to control blood pressure, normalize digestive function, cure constipation, treat diarrhoea and dysentery. High potassium and magnesium levels in these fruits help to protect against heart disease. These fruits also contain vitamin A, which is beneficial for a healthy skin, hair and eyes. High magnesium content helps balance the water in the body, remove acid from the joints and reduce the symptoms of rheumatism and arthritis. The potassium contained in it, helps fight muscle weakness and fatigue. In the light of the above facts, a biochemical study was made to assess their proximate principle and mineral content to pave the way for better utilization, to meet nutritional security and to aid in disease prevention.

Evaluation of Malus genetic resources for tolerance to apple replant disease (ARD)

Replant disease, also described as soil decline, is known for centuries; yet the ultimate causes remain unknown. After repeated growing of the same plant species, the soil loses its capacity to support the growth of plants of the respective species. Replant disease is characterized by a poor vegetative development, stunted growth and reduced yield in terms of quantity and quality. A growing concern for tree nurseries and orchards is that most dwarfing apple rootstocks used in modern apple cultivation are susceptible to apple replant disease (ARD). Thus, the use of ARD-tolerant rootstocks would be a sustainable and economically advantageous solution. Currently, only a few Malus genotypes less susceptible to ARD are described. Identifying ARD-tolerant genotypes and understanding the molecular and physiological basis underpinning such tolerance are prerequisites for future rootstock breeding. Hence, in a greenhouse bio-test, the responses to ARD were evaluated for 48 Malus genotypes, including 41 accessions of 18 wild apple species and 7 rootstock genotypes. Susceptibility to ARD was classified by an ARD-susceptibility index (ASI) calculated based on biomass and increase in shoot length increase, respectively, after cultivation of each genotype in both ARD-soil and disinfected ARD soil by γ-irradiation. In total, six accessions were categorized as less susceptible based on either the ASI_biomass or the ASI_shoot. These accessions are available for future breeding of less susceptible rootstocks.

The R2R3-MYB transcription factor MdMYB24-like is involved in methyl jasmonate-induced anthocyanin biosynthesis in apple

Anthocyanins in apple species are important secondary metabolites that are beneficial for human health. Previous studies revealed that methyl jasmonate (MeJA) promotes anthocyanin accumulation by up-regulating the transcription of related genes. In this study, we isolated a jasmonate (JA)-induced apple MYB gene, MdMYB24-like (MdMYB24L). The encoded nuclear protein contains a conserved R2R3 domain and is homologous to Arabidopsis thaliana AtMYB24. Additionally, MdMYB24L was observed to interact with JA signaling factors (MdJAZ8, MdJAZ11, and MdMYC2) in yeast and in planta. The MdMYC2 protein was also targeted by MdJAZ8 and MdJAZ11, which are rapidly degraded under MeJA treatment. The overexpression of MdMYB24L resulted in higher anthocyanin contents in the transgenic apple ‘Orin’ calli than in the wild-type control calli. Moreover, the expression levels of the anthocyanin biosynthesis structural genes MdUFGT and MdDFR were up-regulated in the transgenic calli. Furthermore, MdMYB24L positively regulated the transcription of MdDFR and MdUFGT by binding to the MYB-binding site motifs in their promoters. Interestingly, the interaction between MdMYC2 and MdMYB24L further enhanced the transcription of MdUFGT, whereas MdJAZ8 and MdJAZ11 attenuated this effect. We herein provide new details regarding the molecular mechanism by which MYB transcription factors help regulate anthocyanin biosynthesis via JA signaling pathways.

Comparative Transcriptome Analysis between Ornamental Apple Species Provides Insights into Mechanism of Double Flowering

Double-flower ornamental crabapples display eye-catching morphologies in comparison to single flower, but the genetic basis of double-flower development is not yet well known in apples. In order to comprehensively understand the differential expression of genes (DEGs) between single and double flower, the transcriptome of double flower crabapples Malus Kelsey, Malus micromalus, Malus Royalty, and a single flower cultivar Malus Dolgo were compared by RNA-sequencing. The results showed that there were 1854 genes in overlapped DEGs among all sample comparisons in apple single and double flower varieties. A large number of development and hormone related DEGs were also recognized on the basis of GO and KEGG annotations, and most of the genes were found to be down-regulated in double flowers. Particularly, an AGL24-MADS-box gene (MD08G1196900) and an auxin responsive gene (MD13G1137000) were putatively key candidate genes in the development of double flower by weighted gene co-expression network analysis (WGCNA). The study provides insights into the complex molecular mechanism underlying the development of the double flower in apple.

Application of High-Throughput Sequencing to Evaluate the Genetic Diversity Among Wild Apple Species Indigenous to Shandong, China, and Introduced Cultivars

The Taiyi mountainous region of Shandong province in eastern China has an abundance of wild Malus species. We evaluated the genetic diversity of 88 Malus accessions (45 Asian apple cultivars, 10 American apple cultivars, 12 European apple cultivars, 19 Chinese wild apples, and two apple cultivars with unknown origins) based on single-nucleotide polymorphism (SNP) markers. A total of 38,364 SNPs were obtained with an average of 2256 SNPs per chromosome. The average of the polymorphism information content (PIC), gene diversity, and allele frequency for SNPs was 0.268, 0.306, and 0.364, respectively. A circular phylogenetic tree constructed based on SNP data revealed that the 88 Malus accessions could be divided into three groups. However, a population structure analysis suggested the 88 Malus accessions could be divided into four groups. A principal component analysis (PCA) revealed some population stratification. The first three PCs accounted for 41.62% of the population-wide SNP variation, with PC1 accounting for 33.9%. Moreover, the kinship values of the 88 Malus accessions ranged from 0 to 2.36, with 96.42% of the kinship values between 0 and 0.2. A phylogenetic tree and a PCA indicated the Chinese wild apples widely distributed among the cultivated apples had a diverse genetic background. Characterizing the genetic relationships between cultivated apples and Chinese wild apples is essential for increasing the genetic diversity of the germplasms used by apple breeders.

Orchard management under the effects of climate change: implications for apple, plum, and almond growing

The authors analyzed certain species and varieties of fruit tree in which applied crop technology is used and also undergoes the effects of climate change. The aim is to extend productive crop varieties, resistant to disease and pests, in order to obtain superior yields. The research was conducted in orchards located in northwestern Romania (on 8.59ha), intensively cultivated with apple, plum, and almond species. The blooming period of the species and fruit production was studied in 2009, the first year of the farm's commercial production, and then compared to figures from 2016 to see the changes that occurred. Climatic conditions were studied throughout the period of existence of the farm (2002-2016). To determine the influence of the climatic factor on the blooming and production periods, respectively, every year is considered having pre-blooming, blooming, and ripening periods. It was found that climate change influences the annual biological cycle of the trees: the vegetative rest period of the trees shortens, the tree vegetation begins earlier in the spring, and the blooming period is advanced by as much as 10days compared to normal cultivated varieties. All these factors have direct repercussions on the quantity of production.

Development of the droplet-vitrification cryopreservation technique as a viable alternative to the dormant bud technique for recalcitrant pears

The French INRA Pip Fruit Biological Resource Center is in charge of the maintenance, management, characterization and promotion of the traditional and scientific genetic resources of apple, pear, quince and related species. In 2010, the first cryopreservation trials were performed on apple and pear using the dormant bud technique with the main aim of cryopreserving a major part of the INRA Malus and Pyrus collections. However, some accessions, mainly from the Pyrus genus, sometimes responded badly to the dormant bud technique. To optimize the ability to cryopreserve the largest number of accessions in our collections, the droplet-vitrification technique was tested on two cultivars of Pyrus: ‘Williams’ and ‘Conference’, used as controls since 2010. Our objective was to evaluate this method under our experimental conditions and to compare it with the dormant bud technique. Experiments were carried out using samples from a batch of budsticks collected in January 2015, in order to test the impact of several critical steps in the process. With both techniques, the immersion in liquid nitrogen step appeared to have the most important impact on the final results, much more than dehydration and slow-freezing for dormant bud technique or LS and PVS2 steps for droplet-vitrification technique. Regenerated plants were obtained after droplet-vitrification. With some improvements, this method could be a viable alternative to the dormant bud technique and opens up the possibility of new development paths for the optimization of long-term preservation systems of our genetic resources collections.