Cultivar Groups Research Articles

Genetic diversity structure of western-type carrots

BackgroundCarrot is a crop with a wide range of phenotypic and molecular diversity. Within cultivated carrots, the western gene pool comprises types characterized by different storage root morphology. First western carrot cultivars originated from broad-based populations. It was followed by intercrosses among plants representing early open-pollinated cultivars, combined with mass phenotypic selection for traits of interest. Selective breeding improved root uniformity and led to the development of a range of cultivars differing in root shape and size. Based on the root shape and the market use of cultivars, a dozen of market types have been distinguished. Despite their apparent phenotypic variability, several studies have suggested that western cultivated carrot germplasm was genetically non-structured.ResultsNinety-three DcS-ILP markers and 2354 SNP markers were used to evaluate the structure of genetic diversity in the collection of 78 western type open-pollinated carrot cultivars, each represented by five plants. The mean percentage of polymorphic loci segregating within a cultivar varied from 31.18 to 89.25% for DcS-ILP markers and from 45.11 to 91.29% for SNP markers, revealing high levels of intra-cultivar heterogeneity, in contrast to its apparent phenotypic stability. Average inbreeding coefficient for all cultivars was negative for both DcS-ILP and SNP, whereas the overall genetic differentiation across all market classes, as measured by FST, was comparable for both marker systems. For DcS-ILPs 90–92% of total genetic variation could be attributed to the differences within the inferred clusters, whereas for SNPs the values ranged between 91 to 93%. Discriminant Analysis of Principal Components enabled the separation of eight groups cultivars depending mostly on their market type affiliation. Three groups of cultivars, i.e. Amsterdam, Chantenay and Imperator, were characterized by high homogeneity regardless of the marker system used for genotyping.ConclusionsBoth marker systems used in the study enabled detection of substantial variation among carrot plants of different market types, therefore can be used in germplasm characterization and analysis of genome relationships. The presented results likely reveal the actual genetic diversity structure within the western carrot gene pool and point at possible discrepancies within the cultivars’ passport data.

Genetic diversity analysis of Chinese plum (Prunus salicina L.) based on whole-genome resequencing

Chinese plum (Prunus salicina L.), also known as Japanese plum, is gaining importance because of its extensive genetic diversity and nutritional attributes that are beneficial for human health. Single-nucleotide polymorphisms (SNPs) are the most abundant form of genomic polymorphisms and are widely used in population genetics research. In this study, we constructed high-quality SNPs through whole-genome resequencing of 67 Prunus accessions with a depth of ~20× to evaluate the genome-level diversity and population structure. Phylogenetic analysis, principal component analysis, and population structure profiling indicated that the 67 plum accessions could be classified into four groups corresponding to their origin location, the southern cultivar group (SCG), the northern cultivar group (NCG), the foreign cultivar group (FG), and the mixed cultivar group (MG). Some cultivars from South China clustered with the other three groups. The genetic diversity indices including private allele number, observed heterozygosity, expected heterozygosity, and the nucleotide diversity of the SCG were higher than those of the NCG. Gene flow from the SCG to FG was also detected. Based on the distribution of wild resources, we concluded that the domestication center of origin of the Chinese plum was southwestern China. This study also provided genetic variation features and the population structure of Chinese plum cultivars, laying a foundation for breeders to use diverse germplasm and allelic variants to improve Chinese plum varieties.

Development of genome-wide single nucleotide polymorphism markers for variety identification of F1 hybrids in cucumber (Cucumis sativus L.)

Plant variety identification is essential for the official registration of new cultivars and for variety protection. It is therefore imperative to have rapid and highly reliable methods for plant variety identification. In this study, a core 96-SNP set optimized for use with Fluidigm EP1TM assay was developed to facilitate cultivar identification in cucumber. Genotyping-by-sequencing (GBS) of 88 F1 hybrids comprising nine cultivar groups (Korean Gasi, Korean Nakhap, Korean Baekdadagi, Japanese Gasi, Chinese Gasi, Chinese Baekdadagi, Southeast Asian slice, European slice, and pickle groups) was carried out, and a total of 10,996 high-quality SNPs were generated. Population structure, principle component analysis, and hierarchical clustering indicated that the nine cultivar groups were clearly divided into four subpopulations (subpopulation G for Gasi type, B for Baekdadagi type, N for Nakhap type, and E for slice and pickle types). Population differentiation measures based on pairwise FST values indicated that the closest relationship (0.124) was between subpopulations B and N and subpopulations E (0.140) and G, while subpopulations B and E were the most clearly distinct from each other (0.208). The metrics of genetic differentiation measured by AMOVA also indicated that significant genetic division exists among the subpopulations, while variation among cultivars within each subpopulation is extremely low, indicating high genetic exchange within the subpopulations. By applying filtering criteria to the SNPs, including FST and linkage disequilibrium decay values, 240 SNPs were filtered from the original 10,996 for use with a Fluidigm assay, from which a core 96-SNP set was obtained. This set demonstrated high reproducibility and discrimination power. Hierarchical clustering confirmed that the core 96-SNP set could distinguish all 88 cultivars and delineate them clearly according to their population structures. A Mantel test based on 10,996 SNPs and 37 traits revealed a high level of correlation (r = 0.57) between molecular and morphological distance. Our core 96-SNP set is not only suitable for generating signature profiles of released cucumber cultivars, but also represents a promising supplement to morphological trait-based distinctness, uniformity, and stability testing for cultivar identification.

Fingerprinting 146 Chinese chestnut (Castanea mollissima Blume) accessions and selecting a core collection using SSR markers

Chinese chestnut is an important nut tree around the world. Although the types of Chinese chestnut resources are abundant, resource utilization and protection of chestnut accessions are still very limited. Here, we fingerprinted and determined the genetic relationships and core collections of Chinese chestnuts using 18 fluorescently labeled SSR markers generated from 146 chestnut accessions. Our analyses showed that these markers from the tested accessions are highly polymorphic, with an average allele number (Na) and polymorphic information content (PIC) of 8.100 and 0.622 per locus, respectively. Using these strongly distinguishing markers, we successfully constructed unique fingerprints for 146 chestnut accessions and selected seven of the SSR markers as core markers to rapidly distinguish different accessions. Our exploration of the genetic relationships among the five cultivar groups indicated that Chinese chestnut accessions are divided into three regional type groups: group I (North China (NC) and Northwest China (NWC) cultivar groups), group II (middle and lower reaches of the Yangtze River (MLY) cultivar group) and group III (Southeast China (SEC) and Southwest China (SWC) cultivar groups). Finally, we selected 45 core collection members which represent the most genetic diversity of Chinese chestnut accessions. This study provides valuable information for identifying chestnut accessions and understanding the phylogenetic relationships among cultivar groups, which can serve as the basis for efficient breeding in the future.

Response of cucumber cultivars to target spot based on epidemiological components of the disease monocycle

AbstractCorynespora cassiicola is the causal agent of target spot of several cultivated species, among which cucumber is highlighted for frequent reports of yield losses under greenhouse conditions. Given the difficulties managing this disease due to the lack of information about the resistance of cucumber cultivars, the aim of the present study was to evaluate the response of ten cucumber cultivars to C. cassiicola based on epidemiological components of the disease in a greenhouse. Symptoms of target spot were apparent in all cucumber cultivars from the second day of inoculation of C. cassiicola, demonstrating the short incubation period of the disease and the susceptibility of the crop. The components latent period, number of lesions, lesion diameter, disease severity, number of sporulating lesions, number of spores per affected leaf area and number of spores per sporulating lesion varied according to the cucumber cultivar. The monomolecular model showed the best fit to the number of target spot lesions during the ten days of evaluation, showing differences between cultivars for initial inoculum and disease progression rate parameters. Multivariate analysis with the epidemiological components combined identified three groups of cultivars: one group that was less affected by the disease, represented by Safira and Diplomata cultivars; a second group showing intermediate behaviour, including Valent, Eureka, Taiko, Yamarashi and Darlington cvs., and a third group that was most susceptible to the pathogen and was represented by Soldier, Vulcano and Exocet cvs. Safira and Diplomata cultivars showed low level of susceptibility to target spot and can be recommended for areas with high disease intensity.

Phenological features of the growth and development of Itoh Group peony cultivars in the conditions of the M. M. Gryshko National Botanical Garden of the National Academy of Sciences of Ukraine

Purpose. To reveal the peculiarities of the seasonal rhythm of growth and development of Itoh Group peony cultivars in the conditions of the M. M. Hryshko National Botanical Garden National Academy of Sciences of Ukraine. Methods. The objects of research were plants of 24 cultivars of Itoh Group peonies. The research was conducted on the experimental field of the Department of Flowering and Ornamental Plants of the M. M. Hryshko National Botanical Garden National Academy of Sciences of Ukraine during 2017–2020. The sum of effective temperatures was calculated by summing the daily air temperatures reduced by the biological zero. Results. The phenological phases of Ito Group cultivars growth were determined. Phenological spectra for different groups are presented. It was determined that the flowering of early cultivars: ‘First Arrival’, ‘Hillary’, ‘Julia Rose’, ‘Morning Lilac’, ‘Old Rose Dandy’, ‘Sonoma Apricot’ starts at the sum of effective temperatures ≥ 400 °С. The middle group hybrids bloom when the sum of temperatures reaches 450 °С. This group includes: ‘Bartzella’, ‘Callie’s Memory’, ‘Cora Louise’, ‘Lollipop’, ‘Scarlet Heaven’, ‘Sonoma Velvet Ruby’, ‘Yellow Dream’, ‘Yellow Emperor’, ‘Yellow Heaven’, ‘Yellow Waterlily’. Late flowering group includes: ‘Border Charm’, ‘Garden Treasure’, ‘Kopper Kettle’, ‘Pastel Splendor’, ‘Prairie Charm’, ‘Viking Full Moon’, ‘White Emperor’, ‘Yankee Doodle Dandy’; accumulation of effective temperatures above 500 °С is an essential requirement for their flowering. Conclusions. Itoh Group cultivars successfully pass all phases of seasonal development and manage to complete the growing season. Cultivars belong to the spring-summer-autumn-green phenorhythmotype. The onset of the corresponding phenological phases in peonies of the studied group of cultivars requires a certain sum of effective temperatures. Plant outgrowth begins on March 23 – April 2, when the sum of effective temperatures ranges from 20–40 °С. The flowering of varieties characterized as late spring, lasts 6–9 days ± 3–4 days, depending on the varietal characteristics and the year of cultivation. A rapid increase in the sum of effective temperatures up to 700 °C shortens the flowering phase by 4–5 days. An assortment of early (May 22–25 ± 2–3 days), medium (May 26–28 ± 3–5 days) and late-flowering (May 29–31 ± 4–6 days) cultivars has been selected, what ensures the continuity of peony flowering during two months.

Verticillium wilt resistant and susceptible olive cultivars express a very different basal set of genes in roots

BackgroundOlive orchards are threatened by a wide range of pathogens. Of these, Verticillium dahliae has been in the spotlight for its high incidence, the difficulty to control it and the few cultivars that has increased tolerance to the pathogen. Disease resistance not only depends on detection of pathogen invasion and induction of responses by the plant, but also on barriers to avoid the invasion and active resistance mechanisms constitutively expressed in the absence of the pathogen. In a previous work we found that two healthy non-infected plants from cultivars that differ in V. dahliae resistance such as ‘Frantoio’ (resistant) and ‘Picual’ (susceptible) had a different root morphology and gene expression pattern. In this work, we have addressed the issue of basal differences in the roots between Resistant and Susceptible cultivars.ResultsThe gene expression pattern of roots from 29 olive cultivars with different degree of resistance/susceptibility to V. dahliae was analyzed by RNA-Seq. However, only the Highly Resistant and Extremely Susceptible cultivars showed significant differences in gene expression among various groups of cultivars. A set of 421 genes showing an inverse differential expression level between the Highly Resistant to Extremely Susceptible cultivars was found and analyzed. The main differences involved higher expression of a series of transcription factors and genes involved in processes of molecules importation to nucleus, plant defense genes and lower expression of root growth and development genes in Highly Resistant cultivars, while a reverse pattern in Moderately Susceptible and more pronounced in Extremely Susceptible cultivars were observed.ConclusionAccording to the different gene expression patterns, it seems that the roots of the Extremely Susceptible cultivars focus more on growth and development, while some other functions, such as defense against pathogens, have a higher expression level in roots of Highly Resistant cultivars. Therefore, it seems that there are constitutive differences in the roots between Resistant and Susceptible cultivars, and that susceptible roots seem to provide a more suitable environment for the pathogen than the resistant ones.

Unravelling Differences in Candidate Genes for Drought Tolerance in Potato (Solanum tuberosum L.) by Use of New Functional Microsatellite Markers.

Potato is regarded as drought sensitive and most vulnerable to climate changes. Its cultivation in drought prone regions or under conditions of more frequent drought periods, especially in subtropical areas, requires intensive research to improve drought tolerance in order to guarantee high yields under limited water supplies. A candidate gene approach was used to develop functional simple sequence repeat (SSR) markers for association studies in potato with the aim to enhance breeding for drought tolerance. SSR primer combinations, mostly surrounding interrupted complex and compound repeats, were derived from 103 candidate genes for drought tolerance. Validation of the SSRs was performed in an association panel representing 34 mainly starch potato cultivars. Seventy-five out of 154 SSR primer combinations (49%) resulted in polymorphic, highly reproducible banding patterns with polymorphic information content (PIC) values between 0.11 and 0.90. Five SSR markers identified allelic differences between the potato cultivars that showed significant associations with drought sensitivity. In all cases, the group of drought-sensitive cultivars showed predominantly an additional allele, indicating that selection against these alleles by marker-assisted breeding might confer drought tolerance. Further studies of these differences in the candidate genes will elucidate their role for an improved performance of potatoes under water-limited conditions.

Hybridisation of Malus sylvestris (L.) Mill. with Malus × domestica Borkh. and Implications for the Production of Forest Reproductive Material

This study focuses on the morphological and genetic characteristics of European crab apple (Malus sylvestris (L.) Mill.) and the occurrence of hybrids in its populations. We analyzed a total of 107 putative European crab apple trees in Slovenia: 92 from nine natural populations, five from a seed stand and 10 from a stand of unnatural origin. We also included 18 domesticated apple trees (Malus × domestica Borkh.) and two Japanese flowering crab apple trees (Malusfloribunda van Houtte) as outliers. The trees were classified into groups of European crab apples, hybrids and domesticated apples according to their morphological and genetic characteristics. Classification based on morphological traits produced different results (58.75% European crab apple, 37.11% hybrids and 4.14% domesticated apple) compared to those based on genetic analysis (70.10% European crab apple, 21.64% hybrids and 8.26% domesticated apple). When genetic and morphological characteristics were combined, only 40.20% of the trees were classified as European crab apple, and an additional group of feral cultivars of domesticated apples (6.18%) was identified. The analysis revealed that hybridization with domesticated apple is taking place in all studied natural European crab apple populations; however, hybrids and feral cultivars only occur to a limited extent. When introducing European crab apple into forests in the future, only genetically verified forest reproductive material obtained exclusively from suitable seed stands should be used.

Effects of Limited Irrigation on Forage Yield, Nutritive Value and Water Use Efficiency of Persian Clover (Trifolium Resupinatum) Compared to Berseem Clover (Trifolium Alexandrinum)

ABSTRACT To evaluate the forage yield and quality of Berseem and Persian clover cultivars, a two-year experiment was conducted during two growing seasons (2017–2018 and 2018–2019). Irrigation was the main factor, including full irrigation (I100), moderately limited (I75), and severely limited irrigation (I50). The sub-factor consisted of ten cultivars of clover, five of which were Persian clover (Pars, Aleshtar, Eghlid, Harat, and Zabol) and five cultivars of Berseem clover (Karaj, Elite, Ekinaton, Vienna, and Alex). The results showed that the highest dry matter (DM) and crude protein (CP) yield under all irrigation levels were obtained from the Berseem clover cultivars. Imposing limited irrigation reduced the DM yield, digestible dry matter (DDM) yield and content, CP yield, dry matter intake (DMI), and relative feed value (RFV) of forage, whereas the content of CP, water-soluble carbohydrates (WSC), neutral detergent fiber (NDF), and acid detergent fiber (ADF) increased. Irrigation water use efficiency (IWUE) for DM, DDM, and CP yield under limited irrigation were also increased. Comparison of two groups of Persian and Berseem clover cultivars also showed that with increasing drought stress intensity, in Berseem cultivars, DM yield, DDM yield and content, and RFV decrease was higher. Increasing IWUE under limited irrigation was higher in Persian cultivars for DM and DDM yield. Overall, Berseem clover had higher forage yield and water use efficiency in all irrigation regimes, and the forage quality of this species showed more sensitivity to drought. Abbreviations :I100, I75, and I50, full, moderately limited, and severely limited irrigation (equivalent to 100, 75, and 50% weekly evaporation and crop water requirement, respectively); DM, dry matter; CP, crude protein; ADF, acid detergent fiber; NDF, neutral detergent fiber; DDM: digestible dry matter; WSC, water-soluble carbohydrates; DMI, dry matter intake; RFV, relative feed value; IWUE, irrigation water use efficiency.

Genetic Kinship and Discrimination between the Cultivars Consisting a Sister Cultivar Group in Spring Orchid Cymbidium goeringii

Genetic Kinship and Discrimination between the Cultivars Consisting a Sister Cultivar Group in Spring Orchid Cymbidium goeringii

Changes in photosynthetic traits and their responses to increasing fertilization rates in soybean (Glycine max (L.) Merr.) during decades of genetic improvement

Changes in photosynthetic traits (PTs) during the long-term genetic improvement of soybean (Glycine max (L.) Merr.) yield have been studied, but detailed information on whether PT responses to environmental stress have improved, and their correlations with seed yield, are still unknown. Our objectives were to describe the changes in soybean PTs - leaf area index (LAI), leaf chlorophyll content (Chl), net photosynthetic rate (PN ), stomatal conductance (gs ), and transpiration rate (E) - during decades of genetic improvement, and to detect whether the responses to increasing fertilizer application rates (FRs) of the PTs of 13 different soybean cultivars released in various decades differed. All of the soybean PTs increased significantly along with the year in which each cultivar was released, under different FR treatments, indicating that PTs have improved during decades of genetic breeding. Medium FR (nitrogen) treatment (150 kg ha -1 ) increased PT values, to different extents, at all the investigated growth stages. Leaf area index, Chl, and PN of the old and middle cultivar groups at the full bloom (R2), full seed (R6), and beginning maturity (R7) stages decreased significantly under high FR treatment (300 kg ha-1 ) compared with the medium FR treatment. The former had no effect on any of the PTs of new cultivar group, or had promotive effects. Thus, the photosynthetic capacities of the new cultivars are more tolerant to high FR-related stress than older cultivars. The photosynthetic capacities, and tolerance to high FR-related stress, of soybean cultivars that were released in different years improved after long-term genetic breeding. © 2021 Society of Chemical Industry.

Genetic Diversity Assessment and Cultivar Identification of Cucumber (Cucumis sativus L.) Using the Fluidigm Single Nucleotide Polymorphism Assay.

Genetic diversity analysis and cultivar identification were performed using a core set of single nucleotide polymorphisms (SNPs) in cucumber (Cucumis sativus L.). For the genetic diversity study, 280 cucumber accessions collected from four continents (Asia, Europe, America, and Africa) by the National Agrobiodiversity Center of the Rural Development Administration in South Korea and 20 Korean commercial F1 hybrids were genotyped using 151 Fluidigm SNP assay sets. The heterozygosity of the SNP loci per accession ranged from 4.76 to 82.76%, with an average of 32.1%. Population genetics analysis was performed using population structure analysis and hierarchical clustering (HC), which indicated that these accessions were classified mainly into four subpopulations or clusters according to their geographical origins. The subpopulations for Asian and European accessions were clearly distinguished from each other (FST value = 0.47), while the subpopulations for Korean F1 hybrids and Asian accessions were closely related (FST = 0.34). The highest differentiation was observed between American and European accessions (FST = 0.41). Nei’s genetic distance among the 280 accessions was 0.414 on average. In addition, 95 commercial F1 hybrids of three cultivar groups (Baekdadagi-, Gasi-, and Nakhap-types) were genotyped using 82 Fluidigm SNP assay sets for cultivar identification. These 82 SNPs differentiated all cultivars, except seven. The heterozygosity of the SNP loci per cultivar ranged from 12.20 to 69.14%, with an average of 34.2%. Principal component analysis and HC demonstrated that most cultivars were clustered based on their cultivar groups. The Baekdadagi- and Gasi-types were clearly distinguished, while the Nakhap-type was closely related to the Baekdadagi-type. Our results obtained using core Fluidigm SNP assay sets provide useful information for germplasm assessment and cultivar identification, which are essential for breeding and intellectual right protection in cucumber.

Assessment of the genetic diversity, population structure and allele distribution of major plant development genes in bread wheat cultivars using DArT and gene-specific markers

Knowledge of the degree of genetic diversity can provide fundamental information to breeders for use in various breeding programmes, for instance for the selection of lines with better adaptability. The genetic diversity analysis of 188 winter wheat genotypes demonstrated that this group of cultivars could be divided into four clusters based primarily on geographical origin. The first group contained mostly American and Asian cultivars, while cluster 2 consisted of Central European cultivars, cluster 3 of Hungarian and South European cultivars and cluster 4 mainly of cultivars from Western Europe. Cultivars used in breeding programmes in Central and South East European breeding programmes were found in all four clusters. Wheat genotypes originating from this region of Europe proved to have greater genetic variability than lines from Western and Northern Europe. Among the four clusters, there were also differencies in the frequencies of winter–spring alleles in Vrn-A1, Vrn-B1, Vrn-D1 vernalisation response genes and in the frequencies of sensitive–insensitive alleles in Ppd-B1 and Ppd-D1 photoperiod response genes, which explained the differences in heading date of the four clusters as well.

Optimized Supply Chain Management of Rice in South Korea: Location–Allocation Model of Rice Production

Planning for optimized farming with the aim of providing ideal site and cultivar selection is critical for a stable and sustainable supply of rice with sufficient quantity and quality to customers. In this study, a range of morphological characteristics and yield of eight rice cultivars that are commonly cultivated in Korea were investigated from 2005 to 2020. All morphological characteristics were significantly different among the eight rice cultivars. The dataset of morphological characteristics and yield was used to isolate groups of similar rice cultivars. The k-means clustering method was used to group the rice cultivars. Three groups (Group 1, Group 2, and Group 3) were created. Most cultivars were in Group 1. High-yielding rice cultivars were in Group 2, while the rice cultivars in Group 3 had the lowest rice grain yield. After grouping these rice cultivars, ideal farming locations for all three rice cultivar groups were identified to reduce transportation cost using an optimized location–allocation model. Simulation results suggested the following: (1) Group 1 should be produced in Jellanam-do (south west region), (2) Group 2 should be produced in Chungcheongnam-do (central west region), and (3) Group 3 should be mainly produced in the central west region of South Korea. Simulation results showed the potential to reduce transportation cost by around 0.014%. This can also reduce 21.04 tons of CO2 emission from a freight truck. Because these eight cultivars only make up 19.76% of the total rice production in South Korea, the cost reduction proportion was only 0.014% of total revenue. In future studies, more rice cultivars should be investigated to increase the efficiency of the model performance.

Genetic divergence in maize regarding grain yield and tassel traits

Maize tassels with a longer length and higher number of branches prevent the passage of solar radiation into the upper plant canopy and act as a drain for photoassimilates that could be used for grain production. This study aimed to verify if there is genetic divergence regarding grain yield and tassel traits among maize cultivars in three agricultural years. Twenty maize cultivars were evaluated and 11 tassel traits and grain yield were measured. Individual and joint analyses of variance were performed for each trait. Principal component analysis was performed, the generalized Mahalanobis distance matrix between cultivars was determined, and the genetic divergence analysis was performed, using the unweighted pair group method with arithmetic mean (UPGMA), which allowed constructing the dendrogram. The cophenetic correlation coeffi cient was calculated to validate the cluster. There is genetic divergence among maize cultivars and six groups of cultivars were formed. Tassel length, total branches number, central spike dry matter, and grain yield are the traits that most contribute to the genetic divergence among maize cultivars.

Analysis of the Volatile Components in Flowers of <i>Paeonia lactiflora</i> Pall. and <i>Paeonia lactiflora</i> Pall. var. <i>Trichocarpa</i>

Paeonia lactiflora Pall. var. trichocarpa is a variety of Paeonia lactiflora Pall., and is currently the peony herb’s principal cultivar group. Here, we study the differences in aromatic components and flowers of different varieties between two groups of cultivars, providing a reference for applying natural fragrance substances of peonies, breeding fragrant flower types, and developing and using improved varieties. Headspace solid-phase microextraction (HS-SPME), gas chromatography-mass spectrometry (GC-MS), peak area normalization for each component relative to content, component library (NIST14/NIST14S) retrieval, and a literature review were used to analyze the volatile compounds in flowers of eight peony varieties, such as “Gaoganhong”, and ten comospore peony varieties, such as “Jinshanhong”. Results showed that the main volatile compound constituents in flowers of the two groups were terpenes and alcohols. Additionally, the content of eucalyptol, caryophyllene, α-Pinene, citronellol, and 3-Hexen-1-ol, acetate, (Z) was high. Peony cultivars contained linalool, (1R)-2,6,6-trimethylbicyclo[3.1.1]hept-2-ene, and 1,4-dimethoxybenzene, while comospore peony varieties contained 1,3,6-octatriene, 3,7-dimethyl-, (Z)-, phenylethyl alcohol, and geraniol. In this study, the differences between the volatile components of flowers of different peony varieties were clarified, laying a foundation for further molecular biology research into the floral fragrance of peonies and the cultivation of new varieties of aromatic peonies. At the same time, it also provides a theoretical basis for the development and application of peony flower by-products.

Coupling the endophytic microbiome with the host transcriptome in olive roots

The connection between olive genetic responses to environmental and agro-climatic conditions and the composition, structure and functioning of host-associated, belowground microbiota has never been studied under the holobiont conceptual framework. Two groups of cultivars growing under the same environmental, pedological and agronomic conditions, and showing highest (AH) and lowest (AL) Actinophytocola relative abundances, were earlier identified. We aimed now to: i) compare the root transcriptome profiles of these two groups harboring significantly different relative abundances in the above-mentioned bacterial genus; ii) examine their rhizosphere and root-endosphere microbiota co-occurrence networks; and iii) connect the root host transcriptome pattern to the composition of the root microbial communities by correlation and co-occurrence network analyses. Significant differences in olive gene expression were found between the two groups. Co-occurrence networks of the root endosphere microbiota were clearly different as well. Pearson’s correlation analysis enabled a first portray of the interaction occurring between the root host transcriptome and the endophytic community. To further identify keystone operational taxonomic units (OTUs) and genes, subsequent co-occurrence network analysis showed significant interactions between 32 differentially expressed genes (DEGs) and 19 OTUs. Overall, negative correlation was detected between all upregulated genes in the AH group and all OTUs except of Actinophytocola. While two groups of olive cultivars grown under the same conditions showed significantly different microbial profiles, the most remarkable finding was to unveil a strong correlation between these profiles and the differential gene expression pattern of each group. In conclusion, this study shows a holistic view of the plant-microbiome communication.

Distribution of two groups of melon landraces and inter-group hybridization enhanced genetic diversity in Vietnam.

To understand the genetic diversity and differentiation of Vietnamese melon (Cucumis melo L.), we collected 64 landraces from the central and southern parts of the country and assessed molecular polymorphism using simple sequence repeat and random amplified polymorphic DNA markers. The Vietnamese melon was divided into seven cultivar groups, namely “Dua le”, “Dua vang”, “Dua bo”, “Dua gang-andromonoecious”, “Dua gang-monoecious”, “Dua thom”, “Montok”, and the weedy-type melon “Dua dai”. Among these, Dua le, Dua vang, Dua bo, and Dua gang-andromonoecious are cultivated on plains and they formed cluster II along with the reference accessions of Conomon and Makuwa. Based on genetic distance, Dua le and Dua vang were regarded as Makuwa and Dua bo and Dua gang-andromonoecious as Conomon. In contrast, Dua thom and Montok are cultivated in highlands, and they formed cluster III along with landraces from the southern and eastern foot of the Himalayas. Dua gang-monoecious which is commonly cultivated in the southern parts of Vietnam, exhibited the greatest genetic diversity, as explained by its possible origin through the hybridization between Dua gang-andromonoecious and Montok. Genetic differences in melon landraces between plains and highlands and hybridization between these two geographical groups have contributed to the enhancement of genetic diversity in Vietnamese melon.

Use of apple tree gene pool to create adaptive cultivars with high quality fruits

The apple tree gene pool was evaluated by resistance to adverse winter conditions based on the analysis of weather data for 50 years. 70% of winter-hardy and highly winter-hardy cultivars were revealed in the group of traditional local cultivars. Many local Central Russian cultivars are widely used in the breeding of new winter-hardy cultivars in central Russia, the Volga region, the Urals, Siberia, the Altai, the Far East and the south of the country. Positive results were obtained by using cultivars obtained from stepped crossbreeding, combining a complex of valuable qualities (winter resistance, immunity to scab, high qualities of fruits) in selection. On the basis of damaging factors' modeling, resistance to -38° C temperature and resistance to frost after thaw were confirmed in most VNIISPK breeding cultivars; winter-hardy cultivars with a resistance threshold -40°C: Vyatich, Orlovskiy partizan, Orlovskoye polesie, Zdorovye, Ministr Kiselev, Pamyat' Semakinu, Rozhdestvenskoye. Cultivars Idared, Golden Delicious, Granny Smith, Gala, Jonagold, Pink Lady, Fuji, Honeycrisp are recommended for use in breeding in combination with winter-resistant cultivars to create new high-quality apple tree cultivars with long keeping quality.