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Heat shock protein 90 (HSP90) is important for many organisms, including plants. Based on the whole genome information, the gene number, gene structure, evolutionary relationship, protein structure, and active site of the HSP90 gene family in Rosa chinensis and Rubus idaeus were determined, and the expression of the HSP90 gene under salt, and drought stresses in two rose varieties Wangxifeng and Sweet Avalanche were analyzed. Six and eight HSP90 genes were identified from R. chinensis and Ru. idaeus, respectively. Phylogenetic analysis revealed that the analyzed genes were divided into two Groups and four subgroups (Classes 1a, 1b, 2a, and 2b). Although members within the same classes displayed highly similar gene structures, while the gene structures and conserved domains of Group 1 (Class 1a and 1b) and the Group 2 (Class 2a and 2b) are different. Tandem and segmental duplication genes were found in Ru. idaeus, but not in R. chinensis, perhaps explaining the difference in HSP90 gene quantity in the two analyzed species. Analysis of cis-acting elements revealed abundant abiotic stress, photolight-response, and hormone-response elements in R. chinensis HSP90s. qRT-PCR analysis suggested that RcHSP90-1–1, RcHSP90-5–1 and RcHSP90-6–1 in Sweet Avalanche and Wangxifeng varieties played important regulatory roles under salt and drought stress. The analysis of protein structure and active sites indicate that the potential different roles of RcHSP90-1–1, RcHSP90-5–1, and RcHSP90-6–1 in salt and drought stresses may come from the differences of corresponding protein structures and activation sites. These data will provide information for the breeding of rose varieties with high stress resistance. [ABSTRACT FROM AUTHOR]

Bulgaria has long-standing traditions of cultivating oil-bearing roses and is one of the leading producers of rose essential oil and rose water worldwide. We studied the genetic diversity of twenty-two R. damascena accessions from Bulgaria and Saudi Arabia using 10 inter-simple sequence repeat (ISSR) primers. In total, 212 bands were generated, of which 204 were polymorphic and eight monomorphic. High mean values of polymorphic information content (0.75), effective multiplex ratio (8.90), resolving power (32.40), marker index (6.59), and percentage of polymorphic bands (96.26) were obtained, implying significant genetic variability between the studied genotypes. The ISSR-based analyses showed that the level of polymorphism in this crop is appreciably high (Ne = 1.28, I = 0.24, He = 0.16). The coefficient of genetic differentiation among pre-defined groups was 0.46, indicating that 46% of total genetic variability was between groups and 54% was within groups. The method was appropriate for distinguishing individuals with a high level of similarity. The genetic relationships analysed with PCoA and hierarchical clustering analyses clearly separated the group of Bulgarian R. damascena accessions collected from local industrial plantations from the other two pre-defined groups. The clustering of Bulgarian rose cultivars and accessions from Saudi Arabia was independent of their geographical origin. The reported data could further facilitate the management of genetic resources and the development of rose breeding programs. Our study provides the first data on the genetic diversity of R. damascena accessions from Bulgaria using ISSR markers. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the content and composition of phenolic compounds in autochthonous rose hips (R. pendulina, R. spinosissima and R. gallica) and to compare them with the content of phenolic compounds in their cultivars ('Harstad', 'Bourgogne', 'Mount Everest', 'Poppius', 'Frühlingsduft', 'Single Cherry', 'Frühlingsmorgen', ' Violacea' and 'Splendens') collected in Arboretum Volčji Potok in Slovenia. The total content of phenolic compounds in the flesh with skin was lowest in 'Mount Everest' (3603.57 mg · kg−1 f.w.), which is derived from R. pendulina, and highest in 'Splendens' (68789.39 mg · g−1 f.w.), which is derived from R. gallica. In seeds, the phenolic compound content was lower, as expected, ranging from 757.02 mg · kg−1 f.w. ('Mount Everest') to 6823.21 mg · kg−1 f.w. ('Single Cherry'). It can be concluded that the cultivars differ significantly from each other due to the content of different bioactive compounds. Based on the obtained results, we cannot determine to which basic rose plant the cultivar belongs based only on the content of one analysed compound. The contents were very different because only one parent plant is known for a given cultivar and breeding programmes in roses were very narrowly focussed on specific targets. [ABSTRACT FROM AUTHOR]

Despite the existence of more than 37,000 different varieties of roses worldwide, there remains a significant interest and high relevance in rose breeding. The rose is the most beloved flower in the world, commonly named the "queen of flowers". In addition to its remarkable ornamental significance, the rose possesses various ecological, environmental, landscaping, food, pharmaceutical and medicinal, cosmetic, and industrial attributes, thereby contributing to its overall socio-economic value. The current study investigated the results of rose breeding in a horticulture research center in the northwest of Romania, with over 70 years of experience. The main method used to generate variability for the selection of new genotypes was artificial hybridization. After 1970, an average of 15-20 crossings per year were carried out, in different parental formulas or types of crosses, with approximately 1,000-2,000 flowers pollinated per parental combination. Thousands of F1 hybrids were obtained annually (approximately 10,000-12,000 hybrids per year, per hybrid combination), and dozens of elites were selected, grafted, and promoted as clonal selections in comparative trials. The success rate in obtaining new varieties through hybridization was 5.1% from total hybrid combinations, 0.72% from total hybrids, and 1.6% from total clonal selections. Of the total new Rosa varieties, hybrid teas represent 11.9%, floribundas 64.2%, shrubs 16.6%, and others 7.1%. Thus, 38 new cultivars suitable for open field cultivation were obtained, showing different habits, decorative value, flowering behavior, flower color, fragrance, resistance to frost or major diseases, and intended use. The exploration of new research directions aimed at harnessing the potential of roses, the region, as well as the socio-economic requirements; interest was undertaken to enhance and beauty degraded or landslide-prone lands, but also to introduce damascene roses, valued within the oil perfume and cosmetics industry. [ABSTRACT FROM AUTHOR]

This study aimed to determine the content and composition of bioactive compounds in autochthonous rose hips (R. pendulina, R. spinosissima, and R. gallica) and to compare them with the content of bioactive compounds in some cultivars ('Harstad', 'Bourgogne', 'Mount Everest', 'Poppius', 'Fruhlingsduft', 'Single Cherry', 'Fruhlingsmorgen', 'Violacea', and 'Splendens') derived from these main species. Due to insufficient information on how bioactive compound content changes when crossing roses, this study also sought to ascertain whether modern rose hip cultivars are still a sufficiently rich source of bioactive compounds and could, therefore, be potentially used as a functional food. All material was collected in the Arboretum Volčji Potok (Slovenia). The ascorbic acid content was highest in the 'Harstad' cultivar (12.79 g/kg FW), and the total organic acid content varied from 1.57 g/kg FW (R. spinosissima) to 34.39 g/kg FW ('Harstad'). Of all the carotenoids analyzed, only lycopene and β-carotene were present in all the samples. The total carotenoid content was highest in the 'Fruhlingsmorgen' cultivar (100.84 mg/kg FW), derived from R. spinosissima, and lowest in the main species, R. spinosissima (9.26 mg/kg FW). It can be concluded, therefore, that the content of bioactive compounds in rose hips of modern cultivars is generally lower than in rose hips of old cultivars and original species included in this study. The research results confirm that modern breeding strategies are mainly focused on goals such as abundant flowering and resistance to diseases and pests and not so much on the content of bioactive compounds. [ABSTRACT FROM AUTHOR]

Oil-bearing Rosa rugosa are popular in the essential oil and perfume markets. The similar botanical characteristics between high-oil-yield or low-oil-yield cultivars are confusing and it is hard for farmers or breeders to identify the high-oil-yield cultivar by phenotype difference. High-resolution melting (HRM) analysis of simple sequence repeats (SSRs) can construct accurate DNA fingerprints quickly, which was shown to be effective for identification of closely related cultivars of R. rugosa. Optimization of HRM-SSR indicated that the 10 µL HRM reaction mixture containing 20 ng of genomic DNA of R. rugosa and 0.75 µL of 10 µmol/L of each primer with an annealing temperature of 64 °C was a robust SSR genotyping protocol. Using this protocol, 9 polymorphic SSR markers with 3–9 genotypes among the 19 R. rugosa cultivars were identified. The top three polymorphic makers SSR9, SSR12 and SSR19 constructed a fingerprint of all cultivars, and the rare insertion in the flanking sequences of the repeat motif of SSR19 generated three characteristic genotypes of three high-oil-yield cultivars. These results may be economical and practical for the identification of high-oil-yield R. rugosa and be helpful for the selection and breeding of oil-bearing roses. [ABSTRACT FROM AUTHOR]

The success of rose breeding programs is low due to poor seed set and germination rate. Determining the combining ability of parents might increase breeding programs’ success. The study was conducted to determine the crossing success of ‘pot miniature rose × cut rose’ combinations. Four different pot miniature rose varieties as the seed parents, and four different cut roses as pollen parents were used as plant material. Eight cross combinations were formed, and 30 crosses were made in each combination. Pollen viability and germination rate, fruit set, seed number per fruit, fruit and seed weight, and seed germination rate were recorded. The pollen germination rate varied between 14.09% (‘Moonlight’) and 31.25% (‘Golden Gate’). Among cross combinations, the fruit set rate ranged from 0% to 83.33%, while the seed number was between 0 and 6.14, and the seed germination rate ranged from 0% to 47.5%. The best combinations were ‘Rosa Bling Love Star × Golden Gate’, ‘Rosa Bling Love Star x Magnum’, ‘Rosa Bling Love Star × Inferno’, and ‘Rosa Shining Star × Inferno’. Except for Hot Jewel as the seed parent, low values were obtained from the traits examined in all combinations where Moonlight was used as the pollen parent. There was a positive correlation between seed number, seed weight and fruit weight. There may be prepollination barriers in ‘pot miniature rose × cut rose’ crosses, but productive seeds and progenies are obtainable. The miniature roses can be successfully used as seed parents when combined with cut roses. [ABSTRACT FROM AUTHOR]

Rose (Rosa spp.) is one of the most economically important ornamental species worldwide. Flower diameter, flower weight, and the number of petals and petaloids are key flower-size parameters and attractive targets for DNA-informed breeding. Pedigree-based analysis (PBA) using FlexQTL software was conducted using two sets of multi-parental diploid rose populations. Phenotypic data for flower diameter (Diam), flower weight (fresh (FWT)/dry (DWT)), number of petals (NP), and number of petaloids (PD) were collected over six environments (seasons) at two locations in Texas. The objectives of this study were to 1) identify new and/or validate previously reported QTL(s); 2) identify SNP haplotypes associated with QTL alleles (Q-/q-) of a trait and their sources; and 3) determine QTL genotypes for important rose breeding parents. Several new and previously reported QTLs for NP and Diam traits were identified. In addition, QTLs associated with flower weight and PD were identified for the first time. Two major QTLs with large effects were mapped for all traits. The first QTL was at the distal end of LG1 (60.44-60.95 Mbp) and was associated with Diam and DWT in the TX2WOB populations. The second QTL was consistently mapped in the middle region on LG3 (30.15-39.34 Mbp) and associated with NP, PD, and flower weight across two multi-parent populations (TX2WOB and TX2WSE). Haplotype results revealed a series of QTL alleles with differing effects at important loci for most traits. This work is distinct from previous studies by conducting co-factor analysis to account for the DOUBLE FLOWER locus while mapping QTL for NP. Sources of high-value (Q) alleles were identified, namely, 'Old Blush' and Rosa wichuraiana from J14-3 for Diam, while 'Violette' and PP-J14-3 were sources for other traits. In addition, the source of the low-value (q) alleles for Diam was 'Little Chief', and Rosa wichuraiana through J14-3 was the source for the remaining traits. Hence, our results can potentially inform parental/seedling selections as means to improve ornamental quality in roses and a step towards implementing DNA-informed techniques for use in rose breeding programs. [ABSTRACT FROM AUTHOR]

Rose (Rosa hybrida) is a major flower crop worldwide and has long been loved for its variety of colors and scents. Roses are mainly used for gardening or cutting flowers and are also used as raw materials for perfumes, cosmetics, and food. Essential oils, which are extracted from the flowers of plants, including roses, have various scents, and the essential oil market has been growing steadily owing to the growing awareness of the benefits of natural and organic products. Therefore, it is necessary to develop a system that stably supplies raw materials with uniform ingredients in line with the continuous increase in demand. In this study, conditions for the efficient induction of callus were established from the petals of the rose breeding line 15R-12-2, which has a strong scent developed by the National Institute of Horticultural and Herbal Science, Rural Development Administration. The highest callus induction rate (65%) was observed when the petals of the fully open flower (FOF) were placed on the SH11DP medium so that the abaxial surface was in contact with the medium. In addition, the VOCs contained in the petals of 15R-12-2 and the petal-derived callus were analyzed by HS-SPME-GC-MS. Thirty components, including esters and alcohols, were detected in the petal-derived callus. Among them, 2-ethylhexan-1-ol, which showed 59.01% relative content when extracted with hexane as a solvent, was the same component as detected in petals. Therefore, petal-derived callus is expected to be of high industrial value and can be suggested as an alternative pathway to obtaining VOCs. [ABSTRACT FROM AUTHOR]

Global biodiversity is contracting rapidly due to potent anthropogenic activities and severe climate change. Wild populations of Rosa chinensis var. spontanea and Rosa lucidissima are rare species endemic to China, as well as important germplasm resources for rose breeding. However, these populations are at acute risk of extinction and require urgent action to ensure their preservation.We harnessed 16 microsatellite loci to 44 populations of these species and analysed population structure and differentiation, demographic history, gene flow and barrier effect. In addition, a niche overlap test and potential distribution modelling in different time periods were also carried out.The data indicate that: (1) R. lucidissima cannot be regarded as a separate species from R. chinensis var. spontanea; (2) the Yangtze River and the Wujiang River function as barriers in population structure and differentiation, and precipitation in the coldest quarter may be the key factor for niche divergence of R. chinensis var. spontanea complex; (3) historical gene flow showed a converse tendency to current gene flow, indicating that alternate migration events of R. chinensis var. spontanea complex between south and north were a response to climate oscillations; and (4) extreme climate change will decrease the distribution range of R. chinensis var. spontanea complex, whereas the opposite will occur under a moderate scenario for the future.Our results resolve the relationship between R. chinensis var. spontanea and R. lucidissima, highlight the pivotal roles of geographic isolation and climate heterogeneity in their population differentiation, and provide an important reference for comparable conservation studies on other endangered species. [ABSTRACT FROM AUTHOR]

Roses are important plants, and they are cultivated worldwide for their beautiful flowers, remarkable scent, and nutritious hips. In this study, we re-sequenced the whole genomes of 57 rose cultivars and one wild species that originated from different regions around the world and had different scents, aiming to evaluate their genetic structure and to detect the potential signature of the selective sweep between different scent groups with single-nucleotide polymorphism (SNP) and indel markers. The roses were sequenced at an average depth of 6× to the reference genome of Rosa 'Old blush'. A total of 2,375,949 SNPs were obtained. The SNP numbers varied among the 58 samples, with an average of 1,271,906 per sample. The phylogeny and population structure revealed that the roses could be divided into three main clusters; however, the groups were not consistent in terms of geographic origin or scent classification. These indicated that rose cultivars have a complex genetic background due to the extensive hybridization between cultivated roses or wild rosa species worldwide. A selective sweep analysis was conducted to detect the selection signatures in rose scent traits. A total of 2430 candidate genes were identified in the strong scent groups, and were at the top 5% FST compared to the moderate group. These genes were significantly enriched in the KEGG pathways of tyrosine metabolism, cyanoamino acid metabolism, alpha-linolenic acid metabolism (13 genes), and phenylpropanoid biosynthesis (30 genes). When the low-scent group was used as the control, 2604 candidate genes were identified at the top 5% FST that were significantly enriched in the KEGG pathways of alpha-linolenic acid metabolism (15 genes), and glutathione metabolism (23 genes). We also observed genes enriched in pathways including the linoleic acid metabolism (five genes), diterpenoid biosynthesis (six genes), and monoterpenoid biosynthesis (seven genes), although they were not significant. These implied a positive selection of rose cultivars with a strong fragrance in terms of fatty acid derivatives, terpenoids and benzenoids/phenylpropanoids during rose breeding. Our study establishes a foundation for the further large-scale characterization of rose germplasm, improving the genetic knowledge of the background of roses. [ABSTRACT FROM AUTHOR]

The success of rose breeding programs is low due to poor seed sets and germination rates. Determining fertile parents and cross combinations that show high compatibility could increase the effectiveness of breeding programs. In this study, three rose varieties belonging to Rosa x hybrida (Jumilia, First Red and Magnum), and two old garden rose species (Black Rose and Cabbage Rose) with known ploidy levels were reciprocally crossbred under controlled conditions to determine the successful crosses by checking fertility. The pollen germination rate (PG), crossability rate (CR), seed number per fruit (SNpF), seed production efficiency (SPE), seed germination rate (SGR), fruit weight (FW), seed weight (SW) and stigma number (SiN), etc. were recorded. Comprehensive fertility index value was calculated. Principal component analysis (PCA), correlation matrix, and hierarchical heat map were used to evaluate the data. The findings showed that old garden roses had more viable pollen than hybrid tea roses. The crossing success improved as pollen fertility increased. Also, female parent fertility improved crossing success just as much as pollen fertility. Although the pollen fertility and stigma numbers were low, some combinations had higher CR and SPE. The maximum SPE (from 8.67% to 19.46%) was determined in combinations where Black Rose was the female parent despite the lower stigma number and low pollen fertility. The highest CR was recorded in Black Rose x First Red (94.36%). All combinations in which Black Rose was used as the female parent had a more stable CR. The SNpF of combinations where hybrid rose varieties were female parents and old garden roses were pollen parents was higher than other combinations where hybrid rose varieties were both female and pollen parents. The SPE in intraspecific crosses was lower than that obtained from interspecific crosses. Moreover, the SGR decreased in combinations that produced heavier seeds. The results suggested that SPE is a more accurate parameter than SNpF in demonstrating combination success in breeding programs. Black Rose x First Red, Black Rose x Jumilia, Black Rose x Magnum and Black Rose x Cabbage Rose combinations can be used successfully as the PCA and heat map showed. Black Rose showed better performance as both seed and pollen parents according to the comprehensive fertility index. From the correlation matrix, it is understood that the number of stigmas cannot be an important criterion in parent selection. Old garden roses can be used as parents to increase the success of breeding programs. However, it is necessary to reveal how successful they are in transferring desired characteristics such as scent, petal number, and color. [ABSTRACT FROM AUTHOR]

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Resistance to rose rosette disease (RRD), a fatal disease of roses (Rosa spp.), is a high priority for rose breeding. As RRD resistance is time-consuming to phenotype, the identification of genetic markers for resistance could expedite breeding efforts. However, little is known about the genetics of RRD resistance. Therefore, we performed a quantitative trait locus (QTL) analysis on a set of inter-related diploid rose populations phenotyped for RRD resistance and identified four QTLs. Two QTLs were found in multiple years. The most consistent QTL is qRRV_TX2WSE_ch5, which explains approximately 20% and 40% of the phenotypic variation in virus quantity and severity of RRD symptoms, respectively. The second, a QTL on chromosome 1, qRRD_TX2WSE_ch1, accounts for approximately 16% of the phenotypic variation for severity. Finally, a third QTL on chromosome 3 was identified only in the multiyear analysis, and a fourth on chromosome 6 was identified in data from one year only. In addition, haplotypes associated with significant changes in virus quantity and severity were identified for qRRV_TX2WSE_ch5 and qRRD_TX2WSE_ch1. This research represents the first report of genetic determinants of resistance to RRD. In addition, marker trait associations discovered here will enable better parental selection when breeding for RRD resistance and pave the way for marker-assisted selection for RRD resistance. [ABSTRACT FROM AUTHOR]

It is unknown why roses are terpene-rich, what the terpene biosynthetic pathways in roses are, and why only a few rose species produce the major components of rose essential oil. Here, we assembled two high-quality chromosome-level genomes for Rosa rugosa and Rosa multiflora. We also re-sequenced 132 individuals from the F1 progeny of Rosa chinensis and Rosa wichuraiana and 36 of their related species. Comparative genomics revealed that expansions of the 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) and terpene synthases (TPSs) gene families led to the enrichment of terpenes in rose scent components. We constructed a terpene biosynthesis network and discovered a TPS-independent citronellol biosynthetic pathway in roses through gene functional identification, genome-wide association studies (GWASs), and multi-omic analysis. Heterologous co-expression of rose citronellol biosynthetic genes in Nicotiana benthamiana led to citronellol production. Our genomic and metabolomic analyses suggested that the copy number of NUDX1-1a determines the citronellol content in different rose species. Our findings not only provide additional genome and gene resources and reveal the evolution of the terpene biosynthetic pathways but also present a nearly complete scenario for terpenoid metabolism that will facilitate the breeding of fragrant roses and the production of rose oil. [Display omitted] • The expansion of the HMGR and TPS genes leads to an enrichment of terpenes in roses • A complete and detailed network of terpenoid metabolism has been unveiled in roses • De novo synthesis of citronellol was successfully achieved in N. benthamiana • The evolutionary trajectory of citronellol biosynthesis in roses has been elucidated Shang et al. discover that the expansion of HMGR and TPS genes leads to the enrichment of terpenes in roses. They identify a three-step pathway in the citronellol synthesis and successfully synthesize it in N. benthamiana. The copy number of NUDX1-1a is a crucial factor in determining the variation of citronellol content in roses. [ABSTRACT FROM AUTHOR]

Drought is a major environmental stress that limits plant growth, so it's important to identify drought-responsive genes to understand the mechanism of drought response and breed drought-tolerant roses. Protein phosphatase 2C (PP2C) plays a crucial role in plant abiotic stress response. In this study, we identified 412 putative PP2C s from six Rosaceae species. These genes were divided into twelve clades, with clade A containing the largest number of PP2Cs (14.1%). Clade A PP2Cs are known for their important role in ABA-mediated drought stress response; therefore, the analysis focused on these specific genes. Conserved motif analysis revealed that clade A PP2Cs in these six Rosaceae species shared conserved C-terminal catalytic domains. Collinearity analysis indicated that segmental duplication events played a significant role in the evolution of clade A PP2C s in Rosaceae. Analysis of the expression of 11 clade A RcPP2Cs showed that approximately 60% of these genes responded to drought, high temperature, and salt stress. Among them, RcPP2C24 exhibited the highest responsiveness to both drought and ABA. Furthermore, overexpression of RcPP2C24 significantly reduced drought tolerance in transgenic tobacco by increasing stomatal aperture after exposure to drought stress. The transient overexpression of RcPP2C24 weakened the dehydration tolerance of rose petal discs, while its silencing increased their dehydration tolerance. In summary, our study identified PP2Cs in six Rosaceae species and highlighted the negative role of RcPP2C24 on rose's drought tolerance by inhibiting stomatal closure. Our findings provide valuable insights into understanding the mechanism behind rose's response to drought. • A total of 412 PP2Cs were identified in six Rosaceae species. • Clade A PP2Cs exhibit a strong response to drought stress in rose. • RcPP2C24 reduces transgenic tobacco and rose petals' drought tolerance. • RcPP2C24 negatively regulates drought response by inhibiting stomatal closure. [ABSTRACT FROM AUTHOR]

Rosa chinensis var. spontanea and R. lucidissima complex are the morphologically very similar key ancestors of modern roses with high importance in rose research and breeding. Although widely distributed in subtropical central and southwestern China, these two taxa are highly endangered. We sampled a total of 221 specimens and 330 DNA samples from 25 populations across the two taxa's whole range. Leaf morphological traits were compared. Two chloroplast DNA intergenic spacers (trn G -trn S, pet L -psb E) and ITS were used for population genetics and phylogenetic study to delimit the boundary between the two taxa, assess the genetic variation, uncover the possible evolutionary mechanism responsible for the differentiation within the complex, and make the conservation recommendations. The complex exhibited high levels of genetic variation (h TcpDNA = 0.768, h TITS = 0.726) and high population differentiation even over small geographic distance. We suggest R. chinensis var. spontanea and R. lucidissma be treated as independent taxa, and the northern populations around and within the Sichuan Basin being R. chinensis var. spontanea , having broader leaflets and paler full-blooming flowers, while those in the middle and southern Yunnan-Guizhou Plateau and the adjacent regions being R. lucidissma , having narrower leaflets and darker full-blooming flowers. Transitional areas between the southeastern Sichuan Basin and northeastern Guizhou are the contact or the hybridization zone of the two taxa. Ancestral haplotypes of the complex (R. lucidissma) evolved at about 1.21–0.86 Mya in southeastern Yunnan-Guizhou Plateau and its adjacent regions and survived there during the Quaternary Oscillation. Ancestral haplotypes of R. chinensis var. spontanea deviated from R. lucidissma at about 0.022–0.031 Mya at the transitional areas (Daloushan and Wulingshan Mountains) between the northeastern edge of Yunnan-Guizhou Plaeteau and the southeastern border of Sichuan Basin, where they survived the LGM. The evolution of the complex included spatial isolation and inter-species hybridization. The complex's endangered status might be the result of over-exploitation for its ornamental and medical value, or due to reforestation of some originally open habitats. We provide specific recommendations for the two taxa's in situ and ex situ conservation. [ABSTRACT FROM AUTHOR]

Rose (Rosa L.) is an economically important ornamental genus that has been cultivated for its scent for the perfume industry since antiquity. However, most modern roses have lost their fragrance during the later stages of the breeding process. Here, 59 species of Rosa, including 24 wild Rosa species, 20 Chinese old garden roses, and 15 modern roses, were examined by headspace solid-phase microextraction and gas chromatography-mass spectrometry. Fifty-three volatile organic compounds (VOCs), including terpenoids, benzenoids/phenylpropanoids, and fatty acid derivatives, were detected with qualitative and quantitative analyses. Thirteen common components, including geraniol, citronellol, 2-phenylethanol, 3,5-dimethoxytoluene, 1,3,5-trimethoxybenzene, germacrene D, and cis-3-hexenyl acetate, were found. Furthermore, different wild species or cultivars showed different characteristic compounds. 3,5-Dimethoxytoluene and 1,3,5-trimethoxybenzene were the main compounds in Rosa odorata and Rosa chinensis, which are the original parents of modern roses. 2-Phenylethanol, citronellol, and geraniol were the main aromatic compounds in Rosa damascene and Rosa centifolia. Methyl salicylate, eugenol, methyl eugenol, and benzyl acetate were lost during domestication and breeding of wild Rosa species to Chinese old garden roses and then to modern cultivars. Geranyl acetate, neryl acetate, and dihydrob-ionol were gained during this time and showed higher amounts across the rose breeding process. Natural and breeding selection may have caused volatile compound gains and losses. These findings provide a platform for mining scent-related genes and for breeding improved ornamental plants with enhanced flower characteristics to develop new essential oil-producing plants. [ABSTRACT FROM AUTHOR]

With pronounced morphological and phenological diversity, garden roses have always been part of urban plantings. The significance of roses in ornamental and utilitarian (edible) horticulture can significantly be amended with novel ecosystem services, by shifting their breeding targets towards more than aesthetic and nutritional value. Thus the aim of this paper was to investigate the possibilities of newly bred (within the past decade) garden roses from the ‘Mella’ series as a possible ornamental, disease tolerant and bee attracting cultivars to be recommended in urban ecosystems, adding values to their current ecosystem services. Research goals were to determine the morphological characteristics; honey and wild bees’ abundance and its correlation with rose morphological and floral characteristics; disease resistance/tolerance to main rose fungal diseases; and suitability of ‘Mella’ roses in urban greenery providing multiple ecosystem services. Plant material included seven garden rose cultivars from the ‘Mella’ series. Analyses included complete morphological—qualitative and quantitative characterization of plant and flower traits, fragrance panel scoring and volatile components analyses, counts of honey bees visiting flowers and counts of different wild bee species as potential pollinators. Based on the obtained results significant variability in vegetative and generative plant characteristics was noted in investigated ‘Mella’ roses. With their ‘naturalistic’ overall appearance, comparable with wild roses, ‘Mella’ cultivars differed in plant height and habitus, number and type of flowers, leaf coloration and glossiness, but ‘Barbie Mella’ and ‘Ruby Mella’ positioned as the most decorative ones. ‘Barbie Mella’ was highly scored for overall fragrance, with the most divergent panel records for fragrance components and mixed volatile compounds, characterized by the balanced ratio (almost 1:1:1) between aromatic alcohol + terpenoids, straight-chain alkanes and long-chain alkanes. In relation to the honey bee’s attraction, a combination of plant height, fragrance, flower type (single, simple), flower diameter and accessibility seems to be crucial, rather than any characteristic solely. As an outstanding bee-attractor ‘Barbie Mella’ should be promoted as an ornamental disease-tolerant rose cultivar. Due to their aesthetic values, disease tolerance and bees visitations, ‘Mella’ roses ‘Barbie’, ‘Ruby’, ‘Ducat’ and ‘Exotic’ should be planted as a part of urban semi-natural gardens/landscapes, concomitantly contributing to the multiple ecosystem services—provisioning, regulating, cultural and supporting. Until their worldwide availability, other ‘Mella’-like wild and cultivated roses should be investigated and promoted likewise.

Roses are highly valuable within the flower industry. The metabolites of anthocyanins, flavonols, and carotenoids in rose petals are not only responsible for the various visible petal colors but also important bioactive compounds that are important for human health. In this study, we performed a QTL analysis on pigment contents to locate major loci that determine the flower color traits. An F1 population of tetraploid roses segregating for flower color was used to construct an ultra-high-density genetic linkage map using whole-genome resequencing technology to detect genome-wide SNPs. Previously developed SSR and SNP markers were also utilized to increase the marker density. Thus, a total of 9,259 markers were mapped onto seven linkage groups (LGs). The final length of the integrated map was 1285.11 cM, with an average distance of 0.14 cM between adjacent markers. The contents of anthocyanins, flavonols and carotenoids of the population were assayed to enable QTL analysis. Across the 33 components, 46 QTLs were detected, explaining 11.85–47.72% of the phenotypic variation. The mapped QTLs were physically clustered and primarily distributed on four linkage groups, namely LG2, LG4, LG6, and LG7. These results improve the basis for flower color marker-assisted breeding of tetraploid roses and guide the development of rose products. [ABSTRACT FROM AUTHOR]

The CCCH(C3H) transcription factor is an important transcription factor in plants in the process of plant development, hormone regulation and under stress. Rose is one of the most important commercial flower crops worldwide. However, there are few reports about the C3H gene of rose and Rosa chinensis Jacq. The reference genome sequence becomes a valuable source of data for the C3H genes in rose (RcC3Hs). We identified 31 encoding members in total, which were distributed on seven chromosomes and clustered into 11 subgroups in R. chinensis. Each subgroup has similar group-specific features including motifs, gene structure, cis-acting elements and collinearity in R. chinensis and two other species (Arabidopsis thaliana and Oryza sativa L). The RcC3Hs' tissue-specific expression by quantitative real-time PCR (qRT-PCR) showed that the expression of RcC3Hs was higher in roots and leaves compared with other tissues. These results provide a theoretical basis for the follow-up exploration of the functions of RcC3Hs and the molecular breeding of rose. Supplemental data for this article is available online at https://doi.org/10.1080/13102818.2021.1901609. [ABSTRACT FROM AUTHOR]

Key message: The genetic determinism of prickle in rose is complex, with a major locus on LG3 that controls the absence/presence of prickles on the rose stem. Rose is one of the major ornamental plants. The selection of glabrous cultivars is an important breeding target but remains a difficult task due to our limited genetic knowledge. Our objective was to understand the genetic and molecular determinism of prickles. Using a segregating diploid rose F1 population, we detected two types of prickles (glandular and non-glandular) in the progeny. We scored the number of non-glandular prickles on the floral and main stems for three years. We performed QTL analysis and detected four prickle loci on LG1, 3, 4 and 6. We determined the credible interval on the reference genome. The QTL on LG3 is a major locus that controls the presence of prickles, and three QTLs (LG3, 4 and 1) may be responsible for prickle density. We further revealed that glabrous hybrids are caused by the combination of the two recessive alleles from both parents. In order to test whether rose prickles could originate from a 'trichome-like structure,' we used a candidate approach to characterize rose gene homologues known in Arabidopsis, involved in trichome initiation. Four of these homologues were located within the overlapping credible interval of the detected QTLs. Transcript accumulation analysis weakly supports the involvement of trichome homologous genes, in the molecular control of prickle initiation. Our studies provide strong evidence for a complex genetic determinism of stem prickle and could help to establish guidelines for glabrous rose breeding. New insights into the relationship between prickles and trichomes constitute valuable information for reverse genetic research on prickles. [ABSTRACT FROM AUTHOR]

Drawing on classic articles on the field, approaches of New Area Studies and primary research on journals and study programmes, this article discusses the current state of Southeast Asian studies from a German perspective. Southeast Asian studies has transformed from a field informed by particular political interests into a container category subsuming various different scholarly programmes. Some of these are closely connected to various disciplines, others are trans- or interdisciplinary; some are in close contact with Southeast Asian policy-makers, for instance by educating their future bureaucrats and politicians, and others remain at a distance. Thirty years after the Cold War formally ended, Southeast Asian studies programmes differ vastly in their respective characteristics and outlooks. This article maps some of these and explores their similarities and differences as well as their relationships to the established disciplines. [ABSTRACT FROM AUTHOR]

This study was conducted on two varieties of rose flowers, red variety Rosa and whit variety Krohen, aimed for extending the vase life of flowers under wet storage conditions for seven days at a temperature of 1 ± 6 (T1), 1 ± 10 (T2), 25°C (T3) and relative humidity 80-90%. The results of the present study showed that the red variety and temperature 6°C were significantly decreased the respiration rate, amount of water lost, increased the amount of water absorbed, water balance and vase life compared to the white variety and room temperature. [ABSTRACT FROM AUTHOR]

The article focuses on the effect of auxins and rootstock on greenhouse rose, also known as Rosa Hybrida. Topics discussed include testing the cultivar budding using cuttage-buddage method, climate conditions of Punjab and Ludhiana, India, and statistics recorded on number of flowers in various varieties such as R. indica, and R. multiflora.

The fungal pathogen, Diplocarpon rosae, infects only roses (Rosa spp.) and leads to rose black spot disease. Rose black spot is the most problematic disease of outdoorgrown roses worldwide due to the potential for rapid leaf chlorosis and defoliation. Eleven races of the pathogen were previously characterized from isolates collected in North America and Europe. Isolates of D. rosae obtained from infected leaves of the roses Brite EyesTM ('RADbrite'; isolate BEP; collected in West Grove, PA) and Oso Easy Paprika ('CHEwmaytime'; isolate PAP; collected in Minneapolis, MN) proved to have unique infection patterns using the established host differential with the addition of Lemon FizzTM ('KORlem'). The new races are designated race 12 (BEP) and race 13 (PAP), respectively, and Lemon FizzTM should be included in the updated host differential because it distinguishes races 7 and 12. Additionally, inconsistent infections and limited sporulation were found in the host differential Knock Out ('RADrazz') for races 7 and 12. Expanding the collection of D. rosae races supports ongoing research efforts, including host resistance gene discovery and breeding new rose cultivars with increased and potentially durable resistance. [ABSTRACT FROM AUTHOR]

Key message: Rose morphological traits such as prickles or petal number are influenced by a few key QTL which were detected across different growing environments—necessary for genomics-assisted selection in non-target environments.Abstract: Rose, one of the world’s most-loved and commercially important ornamental plants, is predominantly tetraploid, possessing four rather than two copies of each chromosome. This condition complicates genetic analysis, and so the majority of previous genetic studies in rose have been performed at the diploid level. However, there may be advantages to performing genetic analyses at the tetraploid level, not least because this is the ploidy level of most breeding germplasm. Here, we apply recently developed methods for quantitative trait loci (QTL) detection in a segregating tetraploid rose population (F1 = 151) to unravel the genetic control of a number of key morphological traits. These traits were measured both in the Netherlands and Kenya. Since ornamental plant breeding and selection are increasingly being performed at locations other than the production sites, environment-neutral QTL are required to maximise the effectiveness of breeding programmes. We detected a number of robust, multi-environment QTL for such traits as stem and petiole prickles, petal number and stem length that were localised on the recently developed high-density SNP linkage map for rose. Our work explores the complex genetic architecture of these important morphological traits at the tetraploid level, while helping to advance the methods for marker-trait exploration in polyploid species. [ABSTRACT FROM AUTHOR]

Leaf methanolic extracts of four wild Rose species (Rosa canina L., R. corymbifera Borkh., R. micrantha Borrer ex Sm and R. sempervirens L.) grown in Sicily were analysed in order to evaluate differences among indigenous roses which could be used such as source of bioactive compounds and natural antioxidants. Leaves were harvested during two different periods (June and October) and their morphological characteristics were described. Leaf content of chlorophylls, total anthocyanins, total flavonoids, total polyphenols (Folin-Ciocalteu method) and antioxidant activity (DPPH method) were determined. Results showed that the contents of chlorophylls and carotenoids were higher in leaves of all species harvested in June than in those harvested in October. On the contrary, total anthocyanins of R. micrantha and R. corymbifera leaves were higher in October. Total polyphenol content was higher in leaves of all species were harvested in October. No difference in total flavonoids content was recorded between the two harvest periods but only among the four species. Antioxidant activity was generally high in leaf extracts of all species in both periods and, particularly, in R. micrantha leaves harvested in June. These outcomes seem to support the assessment that leaves harvested from some Sicilian wild roses may be used as promising source of healthy compounds and that their content varies with the species and harvest period. [ABSTRACT FROM AUTHOR]

In vitro propagation of Rosa hybrida, L. cv. 'Eiffel Tower' was improved by the addition of thidiazuron (TDZ) and silver nitrate (AgNo3) to the culture medium. The combination of auxin and cytokinins was indispensable for inducing response from leaf discs. Maintaining cultures under dark was better than light for callus formation and quality. The source of explants was vital in the regeneration process wherein situ explants produced callus while, in vitro explants regenerated somatic embryos and shoots. Gibberellic acid (GA3) had a favorable effect where in vitro explants showed somatic embryogenesis with no shoots on media containing TDZ however, 37% of explants regenerated shoots directly on medium containing GA3. The presence of benzyl adenine (BA) was essential for shoot elongation, and indole butyric acid (IBA) was better than indole acetic acid (IAA) for rooting. The optimum conditions produced rooted plants from leaf discs within ten weeks. The reported results clarify factors controlling in vitro regeneration of R. hybrida, and provide a rapid protocol allowing further improvements of rose. [ABSTRACT FROM AUTHOR]

Floriculture has become an important industry in many countries as a result of advanced scientific techniques and stable supply of improved varieties. Development of new varieties and their fast marketing are major challenges in floriculture trade. Rose is grown mainly for cut flowers for floriculture industry. All the present-day colourful varieties and their novelties are the result of extensive random hybridization, spontaneous and induced mutations and selections. Voluminous literature is now available on rose breeding using different technology. Here we highlight how present knowledge can be exploited to regulate various desirable characters of rose for selective hybridization, target-oriented induced mutation and in vitro mutagenesis. Molecular breeding offers new and exciting challenges for future improvement of rose. [ABSTRACT FROM AUTHOR]