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Tetraploid plants always exhibit noticeable changes in tissue structure and stress tolerance, but the underlying physiological mechanisms remain poorly understood. Here, we generated a tetraploid plant of Populus davidiana using colchicine induction and performed phenotypic characterization. The results showed that the tetraploid plant had bigger ground diameters and leaf area than the diploid plant. The tetraploid plant had thicker palisade tissue but less stomatal density than the diploid plant. The tetraploid plant also had higher chlorophyll content, net photosynthetic rate, maximal efficiency of PSII photochemistry, the effective quantum yield of PSII, photochemical quenching coefficient but lower non-photochemical quenching coefficient than the diploid plant. Furthermore, we found that the tetraploid plant displayed significantly enhanced drought and salt tolerance in comparison with the diploid progenitor. Our results not only revealed the structural and physiological changes in the tetraploid plant, but also provided a reference for the generation of better quality varieties.Key message: In this study, a tetraploid poplar was obtained and phenotypic analysis revealed the structural and physiological changes of tetraploid poplar compared with its diploid ancestor. [ABSTRACT FROM AUTHOR]

Elsholtzia splendens Nakai ex F. Maek. has been employed in traditional Chinese medicine for millennia. Nevertheless, the small size and the paucity of research on its pharmacological effects have restricted its extensive utilisation in clinical medicine. Polyploid breeding represents an effective method for the rapid enhancement of plant biomass and metabolites. In this study, the most effective in vitro method for inducing tetraploid formation was identified as axillary buds treated in a solution of colchicine at a concentration of 1% for 24 h. Meanwhile, a comparison between tetraploids and diploids yielded two significant findings: (1) The presence of 6-zonocolpate and 8-zonocolpate pollen grains can be used as distinguishing characteristics for diploid and tetraploid, respectively. (2) Genome duplication resulted in alterations to the polyphenol species and synthesis pathway in E. splendens. The accumulation of wogonin, oroxylin A, baicalin, chrysin, acacetin and related derivatives was markedly greater in tetraploid plants, whereas apigenin, naringenin, scutellarein and related derivatives were found to accumulate to a greater extent in diploid plants. It is noteworthy that wogonin and oroxylin A were uniquely detected in tetraploids, indicating that the generated tetraploids may harbor novel pharmacological value. The findings not only provided new insights into the metabolic mechanism of polyploidisation but also established a foundation for the selection and breeding of novel genetic resources of E. splendens. [ABSTRACT FROM AUTHOR]

Introduction: Citrus is an important fruit crop for human health. The sensitivity of citrus trees to a wide range of abiotic stresses is a major challenge for their overall growth and productivity. Among these abiotic stresses, salinity results in a significant loss of global citrus yield. In order to find straightforward and sustainable solutions for the future and to ensure citrus productivity, it is of paramount importance to decipher the mechanisms responsible for salinity stress tolerance. Thisstudy aimed to investigate how ploidy levels influence salt stress tolerance in citrus by comparing the transcriptomic responses of diploid and tetraploid genotypes. In a previous article we investigated the physiological and biochemical response of four genotypes with different ploidy levels: diploid trifoliate orange (Poncirus trifoliata [L.] Raf.) (PO2x) and Cleopatra mandarin (Citrus reshni Hort. Ex Tan.) (CL2x) and their respective tetraploids (PO4x, CL4x). Methods: In this study, we useda multifactorial gene selection and gene clustering approach to finely dissect the influence of ploidy level on the salt stress response of each genotype. Following transcriptome sequencing, differentially expressed genes (DEGs) were identified in response to salt stress in leaves and roots of the different citrus genotypes. Result and discussion: Gene expression profiles and functional characterization of genes involved in the response to salt stress, as a function of ploidy level and the interaction between stress response and ploidy level, have enabled us to highlight the mechanisms involved in the varieties tested. Saltstress induced overexpression of carbohydrate biosynthesis and cell wall remodelling- related genes specifically in CL4x Ploidy level enhanced oxidative stress response in PO and ion management capacity in both genotypes. Results further highlighted that under stress conditions, only the CL4x genotype up- regulated genes involved in sugar biosynthesis, transport management, cell wall remodelling, hormone signalling, enzyme regulation and antioxidant metabolism. These findings provide crucial insights that could inform breeding strategies for developing salt-tolerant citrus varieties. [ABSTRACT FROM AUTHOR]

Centella asiatica (L.) Urban, a tropical herb, has been used both as a vegetable and a medicinal herb. The induction of polyploidy in C. asiatica represents an alternative approach to enhance its yield through breeding. The objective of this study was to induce polyploidy in C. asiatica by treating its seeds with colchicine, with the intention to create a genetically diverse population. The seeds of C. asiatica were treated with 0.0, 0.1, 0.2, 0.3 and 0.4% colchicine for 12 and 24 h. Subsequently, the agricultural characteristics were studied. Ploidy levels were examined through flow cytometry analysis and morphological characteristics were studied. It was found that the concentrations of colchicine significantly resulted in the germination, abnormality, height, and number of leaves of 1-month old seedlings. Studies have shown that both 12 and 24 h exposure to 0.2% colchicine resulted in maximum seedling abnormalities. When the polyploidy of 5-month-old C. asiatica seedlings were examined, examination of putative tetraploid revealed that treatments treated with colchicine T4 (0.1, 24), T6 (0.2, 24) and T9 (0.4, 12) were 100% tetraploid. The study revealed that treating with 0.1, 0.2% colchicine for 24 h and 0.4% colchicine for 24 h promotes polyploidy easily and efficiently. Polyploids feature bigger leaves, longer stems, and a more intense green color. [ABSTRACT FROM AUTHOR]

A new hexaploid cytotype of Aegilops crassa has been identified in Türkiye. To assess the ploidy levels of native populations, 50 samples from Adıyaman, Batman, Bitlis, Diyarbakır, Hakkari, Mardin, Siirt, Şanlıurfa, Şırnak, and Van were analyzed using flow cytometry and cytogenetic techniques. DNA content was determined by comparison with standard plants. Results confirmed two cytotypes in Türkiye: tetraploid populations from Batman, Bitlis, Diyarbakır, Hakkari, Mardin, Siirt, Şanlıurfa, and Şırnak, and hexaploid accessions from Adıyaman and Van. Ten metaphase plates were analyzed. The tetraploid cytotype exhibited chromosome lengths of 8.95 ± 0.27 to 13.96 ± 0.13 µm, a total genome length of 165.51 ± 0.34 µm, and nuclear DNA content of 18.53 ± 0.29 to 20.37 ± 0.49 pg. Most chromosomes were metacentric, except for chromosomes 7, 8, 10, and 12, which were submetacentric. Two satellite pairs were found on chromosomes 4 and 10. The hexaploid cytotype showed chromosome lengths of 8.90 ± 0.16 to 14.06 ± 0.06 µm, a total genome length of 230.47 ± 0.23 µm, and nuclear DNA content of 33.40 ± 0.52 to 35.01 ± 0.31 pg. Most chromosomes were also metacentric, with three satellite pairs on chromosomes 3, 6, and 10. In conclusion, both tetraploid (2n = 2x = 28) and hexaploid (2n = 6x = 42) cytotypes of Ae. crassa exist in Türkiye, with the hexaploid cytotype having potential for wheat breeding programs. [ABSTRACT FROM AUTHOR]

Abstract [Objective] Using phosphoproteomics, expression patterns of the phosphorylated proteins were analyzed with tetraploid Citrus wilsonii leaves under drought stress, aiming to reveal the mechanism of tetraploid C. wilsonii in response to drought stress and provide support for the improvement of droughttolerant citrus rootstock varieties. [Methods] Phosphorylated proteins in the leaves of tetraploid C. wilsonii after drought stress were identified and analyzed using IMAC affinity enrichment and TMT labeling technology. Functional annotation and metabolic pathway analysis were performed for the differentially expressed phosphorylated proteins. [Results] (1) A total of 3 794 phosphorylation sites and 1 521 phosphorylated proteins were quantified. There were 662 phosphorylated proteins with a fold change exceeding 1.3 (αFC>1.3), which were mainly located in the nucleus (46.07%) and chloroplasts (24.62%). (2) The differentially expressed phosphorylated proteins were mainly involved in binding RNA and Ca2+ , and participating in metabolic pathways such as RNA splicing, photosynthesis, and SNARE interaction in vesicle transport. (3) RT-qPCR results showed that 92.86% of the genes coding the differentially expressed phosphorylated proteins showed similar trend of change in transcriptional and protein levels with the Pearson correlation coefficient of 0.893. [Conclusion] Tetraploid C. wilsonii regulates the proteins involved in RNA splicing and photosynthesis pathway through phosphorylation in response to drought stress.

In plant heredity, the phenotype is the result of observation that can be directly observed, while the genotype is the underlying hidden factor that underlies the expression of the phenotype. The genotype is an important aspect that needs to be understood to explain the pattern of trait inheritance and predict trait inheritance in subsequent generations. The discrete hidden Markov model is a model generated by pair of an unobserved Markov chain and an observation process. This model can be applied to tetraploid plant crosses by modeling genotypes as hidden state and phenotypes as the obeservation process. The probability of dominant phenotype in monohybrid, dihybrid and trihybrid crosses occurring over ten generations during that period is as follows 61,305%, 37,583%, and 23,041%. Furthermore, as more traits are crossed, the probability of dominant phenotype appearing within ten generations decreases. When the dominant phenotype occurs over ten generations, the same genotype can be obtained in monohybrid, dihybrid, and trihybrid crosses, which is heterozygous in the first and second generations, while from the third to the tenth generation it is homozygous dominant.

This research is conducted to study the induction of polyploidization in Katokkon chili using colchicine to study the effect of chromosome doubling or polyploid on certain superior characters during the seedling phase. Some morphological alterations were determined and proven to persist during the seedling phase. The study was conducted in the laboratory and screen house of the Department of Agronomy, Faculty of Agriculture, Universitas Hasanuddin. The polyploidy of the Katokkon chili is induced by soaking the germinated seeds in 0%, 0.05%, 0.1%, and 0.2% colchicine solutions for 6, 12, 24, and 48 hours each. Ploidy levels are analyzed using flow cytometry (Partec®Cy-Flow Space TM). Results show significant differences in colchicine treatment affecting all parameters observed: hypocotyl base of sprouts, plant height, stomata size, and the number of lateral shoots. Flow cytometry analysis histogram confirmed that administration of 0.1% colchicine concentration with 48 hours soaking time and 0.2% colchicine concentration with 24- or 48-hour soaking time can induce tetraploid plants (4n=48) with different coefficients of variance (CV-x%), 5.36%, 4.65%, 6.08%, respectively. Vigorous growth phenotype in leaf size and plant height was more clearly seen in the one-month-old tetraploid Katokkon chili seedlings induced by 0.10% with a soaking time of 48 hours.

Tetraploid oysters are valuable germplasm resources for the production of triploid oysters. However, the broodstock condition and gonadal development of tetraploid oysters are poorly understood. To assess the effects of temperature on gamete quantity and quality, tetraploid and diploid oysters were held at controlled temperatures of 18, 20 and 22 °C for 120 days. The gametogenesis process in tetraploid and diploid oysters showed an accelerated trend in response to increased conditioning temperatures. Nonetheless, the gonadal development of tetraploid oysters was slower than that of diploid oysters. Histomorphometric analysis of gonadal tissues showed variations in observed sex ratio under different conditioning temperatures. The proportions of tetraploid and diploid males increased with elevated temperature. However, survival rates of tetraploid and diploid oysters at 22 °C were significantly lower than those at 18 and 20 °C (P < 0.05). In terms of the number of oocytes and spermatozoa, tetraploid oysters were fewer than diploid oysters. Overall, these results demonstrated the differences in broodstock conditioning and gonadal development between tetraploid and diploid oysters, suggesting the need for specialized broodstock cultivation strategies for tetraploid oysters. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Wildlife & Biodiversity (JWB) is the property of Arak University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Passiflora edulis Sims (2n = 18) is a perennial plant with high utilization values, but its spontaneous polyploidy in nature has yet to be seen. Thus, this study aims to enhance our understanding of polyploidy P. edulis and provide rudimentary knowledge for breeding new cultivars. In this study, colchicine-induced tetraploid P. edulis (2n = 36) was used as experimental material (T1, T2, and T3) to explore the variances between it and its diploid counterpart in morphology, physiology, and biochemical characteristics, and a comparison of their performance under cold stress was conducted. We measured and collected data on phenotype parameters, chlorophyll contents, chlorophyll fluorescence, photosynthesis, osmotic substances, and antioxidant enzymes. The results showed that tetraploid P. edulis exhibited a shorter phenotype, more giant leaves, darker leaf color, and longer and fewer roots. Moreover, the physiological and biochemical analysis indicated that the tetraploid P. edulis had better photosynthesis systems and higher chlorophyll fluorescence parameters than the diploid P. edulis. Additionally, the tetraploid P. edulis had higher activity of antioxidant enzymes (SOD, POD, CAT) and lower MDA content to maintain better resistance in low temperatures. Overall, we conclude that there were apparent differences in the morphological, physiological, and biochemical traits of the tetraploid and diploid P. edulis. The tetraploid plants showed better photosynthesis systems, higher osmotic substance content, and antioxidant enzyme activity than the diploid, even under cold stress. Our results suggest that tetraploids with more abundant phenotype variation and better physiological and biochemical traits may be used as a new genetic germplasm resource for producing new P. edulis cultivars. [ABSTRACT FROM AUTHOR]

Watermelon (Citrullus lanatus) is a plant that is widely cultivated by the community. The seedless watermelon is an F1 hybrid watermelon resulting from a cross between a diploid male watermelon and a tetraploid female watermelon. The low number of seeds produced by tetraploid watermelons is a problem at the seed producer level. This study aims to study the appearance and formation of tetraploid characters in fruits resulting from combinations of diploidtetraploid crosses. This research was conducted in August – November 2020 in Pamekasan, Madura. The design used was a Sigle Plot Design using the single plant method, using 2 F1 genotypes (diploid x tetraploid), 1 backcross genotype ((diploid x tetraploid) x tetraploid), 1 diploid genotype, 1 tetraploid genotype. 2 genotypes of F1 and 1 genotype of backcross were treated with selfing, cross with diploid, and cross with tetraploid so that 9 treatments were obtained. The results showed that the watermelon genotype used was diploid based on the observed fruit characters, namely fruit weight, fruit diameter, dkin thickness, flesh thickness, and number of seeds. The character of skin colour and fruit flesh colour follows their parents. [ABSTRACT FROM AUTHOR]

Perilla [ Perilla frutescens (L.) var frutescens ] is a traditional oil crop in Asia, recognized for its seeds abundant in α-linolenic acid (18:3), a key omega-3 fatty acid known for its health benefits. Despite the known nutritional value, the reason behind the higher 18:3 content in tetraploid perilla seeds remained unexplored. Gamma irradiation yielded mutants with altered seed fatty acid composition. Among the mutants, DY-46-5 showed a 27% increase in 18:2 due to the 4-bp deletion of PfrFAD3b , and NC-65-12 displayed a 16% increase in 18:2 due to the loss of function of PfrFAD3 a through a large deletion. Knocking out both copies of FATTY ACID DESATURASE3 (PfrFAD3a and PfrFAD3b) simultaneously using CRISPR/Cas9 resulted in an increase in 18:2 by up to 75% and a decrease in 18:3 to as low as 0.3% in seeds, emphasizing the pivotal roles of both genes in 18:3 synthesis in tetraploid perilla. Furthermore, diploid Perilla citriodora , the progenitor of cultivated tetraploid perilla, harbors only PfrFAD3b , with a fatty acid analysis revealing lower 18:3 levels than tetraploid perilla. In conclusion, the enhanced 18:3 content in cultivated tetraploid perilla seeds can be attributed to the acquisition of two FAD3 copies through hybridization with wild-type diploid perilla. [ABSTRACT FROM AUTHOR]

Phellodendron amurense Rupr. is a precious medicinal tree species in northeast China. However, P. amurense resources have been severely destroyed due to uncontrolled overharvest and the limited innovation of new germplasms by traditional cross-breeding. In this study, polyploid breeding was introduced to the improvement program of P. amurense. Fifty-four tetraploid plants of P. amurense were first produced by colchicine-induced adventitious bud chromosome doubling in stem segment explants. The induction frequency reached 36.16% (1.0 g L−1 colchicine solution for 48 h treatment) and 50.00% (2.0 g L−1 colchicine solution for 24 h treatment), respectively, showing the high efficiency of the somatic chromosome doubling based on the organogenesis system. Tetraploidization resulted in significant phenotypic variation, such as larger and thicker leaves, thicker stems, and bigger stomata. Ultra-performance liquid chromatography–mass spectrometry (UPLC–MS/MS) analysis identified 59 differentially accumulated alkaloids (DAAs) between the leaf and stem samples of tetraploids, including 32 upregulated and 27 downregulated in stems. For both leaf and stem samples, 18 DAAs were identified between diploids and tetraploids, with 16 DAAs upregulated in tetraploid leaves and 8 upregulated in tetraploid stems, suggesting that polyploidization caused significant alterations in alkaloid contents in leaves and stems of P. amurense. The contents of the main medicinal compounds, such as berberine, jatrorrhizine, phellodendrine, and palmatine, increased significantly in the leaf and/or stem samples after polyploidization. This finding implied that polyploid breeding might be an effective approach for improving P. amurense, beneficial to preserving and exploiting natural resources. [ABSTRACT FROM AUTHOR]

Interspecific F1 hybrids between Asian (Oryza sativa) and African rice (Oryza glaberrima) exhibit severe sterility caused by the accumulation of hybrid sterility genes/loci at 15 or more loci. The mechanisms underlying the hybrid sterility genes are largely unknown; however, a few genes associated with the killer–protector system, which is the system most frequently associated with hybrid sterility genes, have been identified. We previously produced fertile plants as tetraploids derived from diploid interspecific F1 hybrids through anther culture; therefore, it was suggested that hybrid sterility could be overcome following tetraploidization. We investigated whether tetraploid interspecific plants produced by crossing are fertile and tested the involvement of hybrid sterility genes in the process. Fertile tetraploid interspecific F1 hybrid plants were obtained by crossing 2 tetraploids of O. sativa and O. glaberrima. To elucidate the relationships between pollen fertility and the hybrid sterility loci in the tetraploid F1 microspores, we performed genetic analyses of the tetraploid F2 hybrids and diploid plants obtained from the microspores of tetraploid interspecific hybrids by anther culture. The result suggested that the tetraploid interspecific hybrids overcame pollen and seed infertility based on the proportion of loci with the killer–protector system present in the tetraploids. The heterozygous hybrid sterility loci with the killer–protector system in the tetraploid segregate the homozygous killed allele (16.7–21.4%), with more than three-quarters of the gametes surviving. We theoretically and experimentally demonstrated that fertile rice progenies can be grown from tetraploid interspecific hybrids. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Plant Production is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Polyploid rice and its reverted diploid show rich phenotypic variation and strong heterosis, showing great breeding value. However, the genomic differences among tetraploids, counterpart common diploids, tetraploid-revertant diploids, and hybrid descendants are unclear. In this work, we bred a new excellent two-line hybrid rice variety, Y Liang You Duo Hui 14 (HTRM12), using Haitian tetraploid self-reverted diploid (HTRM2). Furthermore, we comparatively analyzed the important agronomic traits and genome-wide variations of those closest relatives, Haitian diploid (HT2), Haitian tetraploid (HT4), HTRM2, and HTRM12 in detail, based on multiple phenotypic investigations, genome resequencing, and bioinformatics analysis. The results of agronomic traits analysis and genome-wide variation analysis of single nucleotide polymorphism (SNP), insertion–deletion (InDel), and copy number variation (CNV) show that HT4 and HTRM2 had abundant phenotypic and genomic variations compared to HT2. HTRM2 can inherit important traits and variations from HT4. This implies that tetraploid self-reverted diploid has high potential in creating excellent breeding materials and in breeding breakthrough hybrid rice varieties. Our study verifies the feasibility that polyploid rice could be used as a mutation carrier for creating variations and provides genomic information, new breeding materials, and a new way of application for tetraploid rice breeding. [ABSTRACT FROM AUTHOR]

Cultivated potato, Solanum tuberosum L., is considered an autotetraploid with 12 chromosomes with four homologous phases. However, recent evidence found that, due to frequent large phase deletions in the genome, gene ploidy is not constant across the genome. The elite cultivar "Otava" was found to have an average gene copy number of 3.2 across all loci. Breeding programs for elite potato cultivars rely increasingly on genomic prediction tools for selection breeding and elucidation of quantitative trait loci underpinning trait genetic variance. These are typically based on anonymous single nucleotide polymorphism (SNP) markers, which are usually called from, for example, SNP array or sequencing data using a tetraploid model. In this study, we analyzed the impact of using whole genome markers genotyped as either tetraploid or observed allele frequencies from genotype-by-sequencing data on single-trait additive genomic best linear unbiased prediction (GBLUP) genomic prediction (GP) models and single-marker regression genome-wide association studies of potato to evaluate the implications of capturing varying ploidy on the statistical models employed in genomic breeding. A panel of 762 offspring of a diallel cross of 18 parents of elite breeding material was used for modeling. These were genotyped by sequencing and phenotyped for five key performance traits: chipping quality, length/width ratio, senescence, dry matter content, and yield. We also estimated the read coverage required to confidently discriminate between a heterozygous triploid and tetraploid state from simulated data. It was found that using a tetraploid model neither impaired nor improved genomic predictions compared to using the observed allele frequencies that account for true marker ploidy. In genome-wide associations studies (GWAS), very minor variations of both signal amplitude and number of SNPs supporting both minor and major quantitative trait loci (QTLs) were observed between the two data sets. However, all major QTLs were reproducible using both data sets. [ABSTRACT FROM AUTHOR]

Abstract Background Glehnia littoralis is a medicinal and edible plant species having commercial value and has several hundred years of cultivation history. Polyploid breeding is one of the most important and fastest ways to generate novel varieties. To obtain tetraploids of G. littoralis in vitro, colchicine treatment was given to the seeds and then were screened based on morphology, flow cytometry, and root tip pressing assays. Furthermore, transcriptome analysis was performed to identity the differentially expressed genes associated with phenotypic changes in tetraploid G. littoralis. Results The results showed that 0.05% (w/v) colchicine treatment for 48 h was effective in inducing tetraploids in G. littoralis. The tetraploid G. littoralis (2n = 4x = 44) was superior in leaf area, leaf thickness, petiole diameter, SPAD value (Chl SPAD), stomatal size, epidermal tissues thickness, palisade tissues thickness, and spongy tissues thickness to the diploid ones, while the stomatal density of tetraploids was significantly lower. Transcriptome sequencing revealed, a total of 1336 differentially expressed genes (DEGs) between tetraploids and diploids. Chromosome doubling may lead to DNA content change and gene dosage effect, which directly affects changes in quantitative traits, with changes such as increased chlorophyll content, larger stomata and thicker tissue of leaves. Several up-regulated DEGs were found related to growth and development in tetraploid G. littoralis such as CKI, PPDK, hisD and MDP1. KEGG pathway enrichment analyses showed that most of DEGs were enriched in metabolic pathways. Conclusions This is the first report of the successful induction of tetraploids in G. littoralis. The information presented in this study facilitate breeding programs and molecular breeding of G. littoralis varieties.

Near-infrared spectroscopy (NIR) has become an essential tool for non-destructive analysis in various fields, including aquaculture. This study presents a pioneering application of portable NIR spectrometers to analyze glycogen content in the gonadal tissues of the Pacific oyster (Crassostrea gigas), marking the first instance of developing quantitative models for glycogen in tetraploid C. gigas. The research also provides a comparative analysis with models for diploid and triploid oysters, underscoring the innovative use of portable NIR technology in aquaculture. Two portable NIR spectrometers were employed: the Micro NIR 1700 (908–1676 nm) and the Micro PHAZIR RX (1624–2460 nm). Near-infrared spectra were acquired from the gonadal tissues of diploid, triploid, and tetraploid C. gigas. Quantitative models for glycogen content were developed and validated using cross-validation methods. Additionally, qualitative models for different ploidies and genders were established. For the Micro NIR 1700, the cross-validation correlation coefficients (Rcv) and cross-validation relative predictive errors (RPDcv) for glycogen were 0.949 and 3.191 for diploids, 0.915 and 2.498 for triploids, and 0.902 and 2.310 for tetraploids. The Micro PHAZIR RX achieved Rcv and RPDcv values of 0.781 and 2.240 for diploids, 0.839 and 2.504 for triploids, and 0.717 and 1.851 for tetraploids. The Micro NIR 1700 demonstrated superior quantitative performance, with RPD values exceeding 2, indicating its effectiveness in predicting glycogen content across different ploidy levels. Qualitative models showed a performance index of 91.6 for diploid and 95 for tetraploid genders using the Micro NIR 1700, while the Micro PHAZIR RX achieved correct identification rates of 99.79% and 100% for diploid and tetraploid genders, respectively. However, differentiation of ploidies was less successful with both instruments. This study's originality lies in establishing the first quantitative models for glycogen content in tetraploid C. gigas using portable NIR spectrometers, highlighting the significant advancements in non-destructive glycogen analysis. The applicability of these findings is substantial for oyster breeding programs focused on enhancing meat quality traits. These models provide a valuable phenotyping tool for selecting oysters with optimal glycogen content, demonstrating the practical utility of portable NIR technology in aquaculture. [ABSTRACT FROM AUTHOR]

Polyploidization produces abundant phenotypic variation. Little is currently known about adventitious root (AR) development variation due to polyploidization. In this study, we analyzed the morphological, cytological, and physiological variations in AR development between tetraploid and diploid Populus plants during in vitro rooting culture. Compared to the diploids, the AR formation times and rooting rates of the tetraploids' stem explants had non-significant changes. However, the tetraploid ARs exhibited significantly slower elongation growth than the diploid ARs. Cytological observation showed that the tetraploid ARs were characterized by shorter root meristems and reduced meristem cell numbers, suggesting the reasons for the slow AR elongation. Analysis of hormones and related metabolites during AR development demonstrated that the total auxin, cytokinin, and jasmonic acid contents were significantly lower in the tetraploid ARs than in those of the diploids, and that the ratio of total auxins to total CKs at 0 h of AR development was also lower in the tetraploids than in the diploids, whereas the total salicylic acid content of the tetraploids was consistently higher than that of the diploids. qPCR analysis showed that the expression levels of several hormone signaling and cell division-related genes in the tetraploid ARs significantly differed from those in the diploids. In conclusion, the slow elongation of the tetraploid ARs may be caused by the endogenous hormone-mediated meristem shortening. Our findings enhance the understanding of polyploidization-induced variation in AR development of forest trees. [ABSTRACT FROM AUTHOR]

Perennial ryegrass is the most widely grown temperate grass species globally as a source of forage (grazing, hay, silage) or for amenity use. It is a part of landscape, protects soil from water and wind erosion, enriches it with organic substances and improves its fertility. During the period 2015-2020 in the Institute of Forage crops (IFC) - Pleven a collection nursery was studied in field non-irrigated conditions on leached black soil, in block duplicate method, in 2 replications with a total of 19 accessions of perennial ryegrass, with 50 individual plants each (25 plants for forage and 25 plants - for seeds), including 14 varieties and 5 ecotypes, 10 tetraploid and 9 diploid, from Bulgaria (BG), Belgium (BE), and Romania (RO). The aim is to determine the vitality per year and longevity (after many years, more than 3-4) of perennial ryegrass collection accessions and to make a selection of the most vital and long - lasting genotypes. Scale of survival according to the International Classifier for the family Poaceae (Bukhteeva et al., 1985) was used - limiting factors of the environment are cold - winter, drought and high temperatures - summer. An autumn inventory of the individual plants no./% was carried out annually, as 25 plants per sample = 100%., and vitality classification as follows: Very Low - less than 1 to 20% of plants are left alive; Low - more than 21 to 50%; Medium - more than 51% to 70%; High - more than 71 to 90%; Very High - more than 90% of the plants are still alive. Computer statistical processing of the data (via Excel, at P = 0.05) included variance analyses. Data on vitality and longevity are characterized by: marginal values (min and max), arithmetic mean (x), standard deviation (SD) and coefficient of variation (CV,%). Variation was considered weak, moderate, or strong at CV values, respectively: up to 10%; > 10-20%, and > 20% (Dimova and Marinkov, 1999). When grown for fodder, the local ecotypes Sokolare, Topolovgrad and Bekovi skali are the most viable by years and the longest surviving up to 5 years, with the percentage of plants alive in the fifth year being the highest for the Sokolare ecotype. Ecotype Sokolare is strongly influenced by the method of use, which is the longest-lasting and most viable when grown for fodder - 5 years and the shortest - when grown for seeds - 3 years. All diploid varieties live up to 4 years, and only the Harmoniya variety up to 5 years, with the Bulgarian varieties Harmoniya and Strandzha being the most viable and long-lasting when grown for fodder. Harvesting once a year for seeds extends the life cycle of diploid varieties up to 5 years and for the Harmoniya variety - up to 6. The Bulgarian tetraploid varieties Tetrany, Tetramis and the Belgian varieties Floris, Melpetra and Melverde are the most durable and long-lasting. One-time harvesting per year for seeds extends the life cycle of the tetraploid varieties up to 5 years, and for the Bulgarian varieties Tetrany, Tetramis and the Belgian varieties Floris, Melpetra and Melverde - up to 6. [ABSTRACT FROM AUTHOR]

IntroductionCitrus is an important fruit crop for human health. The sensitivity of citrus trees to a wide range of abiotic stresses is a major challenge for their overall growth and productivity. Among these abiotic stresses, salinity results in a significant loss of global citrus yield. In order to find straightforward and sustainable solutions for the future and to ensure citrus productivity, it is of paramount importance to decipher the mechanisms responsible for salinity stress tolerance. Thisstudy aimed to investigate how ploidy levels influence salt stress tolerance in citrus by comparing the transcriptomic responses of diploid and tetraploid genotypes. In a previous article we investigated the physiological and biochemical response of four genotypes with different ploidy levels: diploid trifoliate orange (Poncirus trifoliata [L.] Raf.) (PO2x) and Cleopatra mandarin (Citrus reshni Hort. Ex Tan.) (CL2x) and their respective tetraploids (PO4x, CL4x).MethodsIn this study, we useda multifactorial gene selection and gene clustering approach to finely dissect the influence of ploidy level on the salt stress response of each genotype. Following transcriptome sequencing, differentially expressed genes (DEGs) were identified in response to salt stress in leaves and roots of the different citrus genotypes.Result and discussionGene expression profiles and functional characterization of genes involved in the response to salt stress, as a function of ploidy level and the interaction between stress response and ploidy level, have enabled us to highlight the mechanisms involved in the varieties tested. Saltstress induced overexpression of carbohydrate biosynthesis and cell wall remodelling- related genes specifically in CL4x Ploidy level enhanced oxidative stress response in PO and ion management capacity in both genotypes. Results further highlighted that under stress conditions, only the CL4x genotype up- regulated genes involved in sugar biosynthesis, transport management, cell wall remodelling, hormone signalling, enzyme regulation and antioxidant metabolism. These findings provide crucial insights that could inform breeding strategies for developing salt-tolerant citrus varieties.

Teak, known for its high-quality timber and economic value, holds significant potential as the major component of an agroforestry system to combat climate change and support sustainable development goals. The challenge of slow teak growth can be addressed by introducing fast-growing teak varieties amenable to vegetative propagation. Furthermore, the improvement of teak through somatic cell genetics, such as inducing polyploidy, can result in more vigorous, faster-growing, and drought-tolerant trees. While a report exists on a tetraploid teak accession with enhanced less water tolerance, information on the induction and characterization of tetraploid teak is lacking. In this study, we report the induction of polyploid teak by immersing 1 – 1.5 cm nodal stem segments and shoot tips obtained from teak shoot cultures in a modified MS liquid medium containing 5 − 30 µM oryzalin for one week, followed by subculture for 6 passages. The resulting shoots were acclimatized and grown in the nursery for 10 months. Based on flow cytometry for ploidy analysis of pre-selected plants having morphologies typical of polyploid followed by chromosome counting, we identified two tetraploid plants from one accession and 18 mixoploid teak plants from four accessions. Chromosome counting analysis confirmed that a diploid plant had a chromosome number of 2n = 2x = 36, tetraploid plant had a chromosome number of 2n = 4x = 72, and mixoploid plant exhibited both chromosome number of 2n = 2x = 36 and 2n = 4x = 72 in root tip cells. Morphological characterization revealed that tetraploid and mixoploid teak plants displayed typical polyploid characteristics, such as larger, thicker, and greener leaves, increased root diameter, increased cell size in root tip region, and larger stomata size but with reduced density. The development of tetraploid teak holds the potential to provide faster-growing and more drought-tolerant varieties, facilitating breeding efforts, including the development of triploid varieties.

Elsholtzia splendens Nakai ex F. Maek. has been employed in traditional Chinese medicine for millennia. Nevertheless, the small size and the paucity of research on its pharmacological effects have restricted its extensive utilisation in clinical medicine. Polyploid breeding represents an effective method for the rapid enhancement of plant biomass and metabolites. In this study, the most effective in vitro method for inducing tetraploid formation was identified as axillary buds treated in a solution of colchicine at a concentration of 1% for 24 h. Meanwhile, a comparison between tetraploids and diploids yielded two significant findings: (1) The presence of 6-zonocolpate and 8-zonocolpate pollen grains can be used as distinguishing characteristics for diploid and tetraploid, respectively. (2) Genome duplication resulted in alterations to the polyphenol species and synthesis pathway in E. splendens. The accumulation of wogonin, oroxylin A, baicalin, chrysin, acacetin and related derivatives was markedly greater in tetraploid plants, whereas apigenin, naringenin, scutellarein and related derivatives were found to accumulate to a greater extent in diploid plants. It is noteworthy that wogonin and oroxylin A were uniquely detected in tetraploids, indicating that the generated tetraploids may harbor novel pharmacological value. The findings not only provided new insights into the metabolic mechanism of polyploidisation but also established a foundation for the selection and breeding of novel genetic resources of E. splendens.

A new hexaploid cytotype of Aegilops crassa has been identified in Türkiye. To assess the ploidy levels of native populations, 50 samples from Adıyaman, Batman, Bitlis, Diyarbakır, Hakkari, Mardin, Siirt, Şanlıurfa, Şırnak, and Van were analyzed using flow cytometry and cytogenetic techniques. DNA content was determined by comparison with standard plants. Results confirmed two cytotypes in Türkiye: tetraploid populations from Batman, Bitlis, Diyarbakır, Hakkari, Mardin, Siirt, Şanlıurfa, and Şırnak, and hexaploid accessions from Adıyaman and Van. Ten metaphase plates were analyzed. The tetraploid cytotype exhibited chromosome lengths of 8.95 ± 0.27 to 13.96 ± 0.13 µm, a total genome length of 165.51 ± 0.34 µm, and nuclear DNA content of 18.53 ± 0.29 to 20.37 ± 0.49 pg. Most chromosomes were metacentric, except for chromosomes 7, 8, 10, and 12, which were submetacentric. Two satellite pairs were found on chromosomes 4 and 10. The hexaploid cytotype showed chromosome lengths of 8.90 ± 0.16 to 14.06 ± 0.06 µm, a total genome length of 230.47 ± 0.23 µm, and nuclear DNA content of 33.40 ± 0.52 to 35.01 ± 0.31 pg. Most chromosomes were also metacentric, with three satellite pairs on chromosomes 3, 6, and 10. In conclusion, both tetraploid (2n = 2x = 28) and hexaploid (2n = 6x = 42) cytotypes of Ae. crassa exist in Türkiye, with the hexaploid cytotype having potential for wheat breeding programs.

Under salt stress, recretohalophyte Plumbago auriculata tetraploids enhance salt tolerance by increasing selective secretion of Na+ compared with that in diploids, although the mechanism is unclear. Using non-invasive micro-test technology, the effect of salt gland Ca2+ content on Na+ and K+ secretion were investigated in diploid and tetraploid P. auriculata under salt stress. Salt gland Ca2+ content and secretion rates of Na+ and K+ were higher in tetraploids than in diploids under salt stress. Addition of exogenous Ca2+ increased the Ca2+ content of the salt gland in diploids and is accompanied by an increase in the rate of Na+ and K+ secretion. With addition of a Ca2+ channel inhibitor, diploid salt glands retained large amounts of Ca2+, leading to higher Ca2+ content and Na+ secretion rate than those of tetraploids. Inhibiting H2O2 generation and H+-ATPase activity altered Na+ and K+ secretion rates in diploids and tetraploids under salt stress, indicating involvement in regulating Na+ and K+ secretion. Our results indicate that the increased Na+ secretion rate of salt gland in tetraploids under salt stress was associated with elevated Ca2+ content in salt gland. [ABSTRACT FROM AUTHOR]

Cross-incompatibility is the major challenge in inter-sectional distant hybridization between tree peonies (Paeonia sect. Moutan) and herbaceous peonies (Paeonia sect. Paeonia). Most of the intersectional cross combinations rarely produce hybrid progenies or even seeds. However, a combination with Paeonia × lemoinei Rehd. (P. delavayi × P. suffruticosa, tree type) as the pollen parent and P. lactiflora (herbaceous) as the seed parent resulted in many progenies. This research focuses on cytogenetics of two highly compatible intersectional combinations, P. lactiflora ‘Martha W.’ × P. × lemoinei ‘Golden Era’ (‘MW’ × ‘GE’) and P. lactiflora ‘Fen Yun Fei He’ × P. × lemoinei ‘L’Esperance’ (‘FYFH’ × ‘LE’). Karyotype analysis combined with genomic in situ hybridization (GISH) showed that the seed parents, ‘MW’ and ‘FYFH’, are both diploids (2n = 2x = 10, CC), while the pollen parents, ‘GE’ and ‘LE’, are tetraploid (2n = 4x = 20, AABB) and diploid (2n = 2x = 10, AB) respectively. Four progenies from ‘MW’ × ‘GE’, and another four progenies from ‘FYFH’ × ‘LE’, are all triploids (2n = 3x = 15, ABC). P. × lemoinei contributes two sets of chromosomes (AB) showing distinct signals in all tested triploids. The essential of a successful intersectional hybridization is to obtain 2x gametes from tree peony. P. × lemoinei has better compatibility in intersectional hybridization than other tree peony species, probably because of its higher frequency of 2x gamete (unreduced in diploid, or reduced in tetraploid) generation. Tetraploid tree peonies, such as ‘GE’, might produce abundant 2x gametes through normal meiosis, which is the possible reason for their better fertility and superior intersectional compatibility than diploid tree peonies. The mechanism of compatibility in intersectional hybridization is supposed to be a rebalance between the distant divergent parents, tree peonies and herbaceous peonies, triggered by ploidy increase of gametes from tree peonies. The discovery of tetraploid tree peony also provides valuable materials to study the mechanism of polyploidization in sect. Moutan, and to promote the distant hybridization breeding in Paeonia. [ABSTRACT FROM AUTHOR]

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One of the important functions of regulated cell death is to prevent cells from inappropriately acquiring extra copies of their genome, a state known as polyploidy. Apoptosis is the primary cell death mechanism that prevents polyploidy, and defects in this apoptotic response can result in polyploid cells whose subsequent error-prone chromosome segregation are a major contributor to genome instability and cancer progression. Conversely, some cells actively repress apoptosis to become polyploid as part of normal development or regeneration. Thus, although apoptosis prevents polyploidy, the polyploid state can actively repress apoptosis. In this review, we discuss progress in understanding the antagonistic relationship between apoptosis and polyploidy in development and cancer. Despite recent advances, a key conclusion is that much remains unknown about the mechanisms that link apoptosis to polyploid cell cycles. We suggest that drawing parallels between the regulation of apoptosis in development and cancer could help to fill this knowledge gap and lead to more effective therapies. [ABSTRACT FROM AUTHOR]

Seedlessness is the most important characteristic of citrus and one of its breeding purposes. Triploids are the most reliable way to secure seedlessness and can be developed through crosses between tetraploids and diploids or between diploids and diploids. We evaluated the characteristics of seed formation and recovery frequency of triploids in interploid crosses in this study. Normal seed formation was the highest (85.0%) in crosses of 2x × 2x, followed by crosses 4x × 2x and 2x × 4x. Partially developed seeds were obtained at the highest rate (35.3%) from crosses of 4x × 2x with 0.7 seeds per fruit, followed by 2x × 2x and 2x × 4x with 0.2 and 0.1 seeds per fruit, respectively. The number of undeveloped seeds per fruit was 1.1, 1.0, and 0.3 from the 4x × 2x, 2x × 4x, and 2x × 2x crosses, respectively, and the lowest frequency was recorded in the 2x × 2x cross. Diploid plants were mostly obtained in the 2x × 2x cross (98.8%), while 73.0% triploids and 27.0% tetraploids were obtained with 4x × 2x, and 14.3% diploids, 57.1% triploids, and 28.6% tetraploids were achieved with the 2x × 4x cross. Diploid plants were mostly obtained from normal seeds, while ad triploid and tetraploid plants were mostly obtained from partially developed and undeveloped seeds. The results indicated that crosses of 4x × 2x were the most efficient and that in vitro culture should be applied to rescue plants from partially developed and undeveloped seeds in triploid breeding programs. [ABSTRACT FROM AUTHOR]

Nonapomictic citrus tetraploids are desirable in citrus breeding for the production of triploid, seedless varieties, and polyploid rootstocks. However, only a few lines have been reported, and they were all generated using chemical methods. A 2x + 4 × cytochimera of the nonapomictic citrus variety 'Orah' mandarin, which developed from a bud mutant, was found due to its morphology differing from that of diploid plants and characterised via ploidy analysis combining flow cytometry and chromosome observation. The chimaera was stable, and there were 1.86–1.90 times as tetraploid cells as diploid cells. Anatomical structure observation revealed that the 'Orah' chimaera may be a periclinal chimaera with diploid cells in the L1 layer and tetraploid cells in the L2 and L3 layers. The chimaera showed some typical traits of polyploid plants, including thicker shoots, wider and thicker leaves, larger flowers and fruits, and fewer but larger seeds in fruits than in diploid plants. Almost all the seeds of the chimaera were monoembryonic. Most of the self-pollinated progenies of the chimaera were identified as tetraploids, and some triploid, pentaploid, and hexaploid plants were found. As a female, the chimaera produced allotriploids when crossed with Australian finger lime. In addition, 6 plants developed from polyembryonic seeds of the chimaera were identified as sexual tetraploid progenies with low-level recombinant genomes. Therefore, the 'Orah' 2x + 4 × chimaera can be used as a female parent to produce hybrid triploid and tetraploid citrus plants with high efficiency. Identification of the chimaera demonstrated that tetraploid citrus plants, especially nonapomictic varieties, can be generated from shoot bud mutants. [ABSTRACT FROM AUTHOR]

The sterility advantages of triploids make them paramount for oyster aquaculture. Tetraploids are always used as male parents for triploid industrial breeding in current hatcheries, thus they are the core asset for triploid oyster culture. The oyster Crassostrea angulata is the most productive oyster species in China. However, the optimal conditions for tetraploid induction have never been examined. In this study, we investigated the effectiveness of three induction methods (Method I, 2n ♀ × 2n ♂ + inducer abbreviated as DD + ind; Method II, 3n ♀ × 2n ♂ + inducer abbreviated as TrD + ind; Method III, 2n ♀ × 4n ♂ + inducer abbreviated as DT + ind) and three inducers (salinity; cytochalasin B, CB; and 6-dimethylaminopurine, 6-DMAP) for tetraploid induction in C. angulata. The optimal induction conditions for the three induction methods were a CB concentration of 0.5 mg/L treated for 20 min, 0.75 mg/L CB for a constant induction treatment of 20 min and 6-DMAP at a concentration of 100 mg/L for 20 min, respectively. When the optimal induction conditions were applied to a single pair of oysters, the D-larval tetraploid rate for the three methods were 18.93 ± 1.46%, 58.32 ± 1.03% and 51.61 ± 1.37%, respectively. After 30 days, the survival rates of the experimental groups were only 10.36 ± 2.51%, 28.07 ± 2.03% and 21.99 ± 1.27%, respectively, at day 30. The tetraploid rates in DD + ind and DT + ind were both decreased significantly over time, but they still reached 11.81% and 21.99% at 30 days, and 8% and 16% at day 180, respectively. Tetraploid rates in TrD + ind were 58.32 − 71.28% at the larval stage and 80% at day 180. In summary, despite very different induction rates, surviving tetraploids of C. angulata could be obtained in all three methods. Method II (TrD + inducer) was regarded as the optimal method to induce C. angulata tetraploids, and the optimal induction condition was a CB concentration of 0.75 mg/L and treated for 20 min under this method. [ABSTRACT FROM AUTHOR]

Lycium chinense, a type of medicinal and edible plant, is rich in bioactive compounds beneficial to human health. In order to meet the market requirements for the yield and quality of L. chinense, polyploid induction is usually an effective way to increase plant biomass and improve the content of bioactive components. This study established the most effective tetraploid induction protocol by assessing various preculture durations, colchicine concentrations, and exposure times. The peak tetraploid induction efficacy, 18.2%, was achieved with a 12-day preculture and 24-h exposure to 50 mg L–1 colchicine. Compared to diploids, tetraploids exhibited potentially advantageous characteristics such as larger leaves, more robust stems, and faster growth rates. Physiologically, tetraploids demonstrated increased stomatal size and chloroplast count in stomata but reduced stomatal density. Nutrient analysis revealed a substantial increase in polysaccharides, calcium, iron, and zinc in tetraploid leaves. In addition, seventeen carotenoids were identified in the leaves of L. chinense. Compared to the diploid, lutein, β-carotene, neoxanthin, violaxanthin, and (E/Z)-phytoene exhibited higher levels in tetraploid strains T39 and T1, with T39 demonstrating a greater accumulation than T1. The findings suggest that the generated tetraploids harbor potential for further exploitation and lay the foundation for the selection and breeding of novel genetic resources of Lycium. [ABSTRACT FROM AUTHOR]

Cultivated potato, Solanum tuberosum L., is considered an autotetraploid with 12 chromosomes with four homologous phases. However, recent evidence found that, due to frequent large phase deletions in the genome, gene ploidy is not constant across the genome. The elite cultivar “Otava” was found to have an average gene copy number of 3.2 across all loci. Breeding programs for elite potato cultivars rely increasingly on genomic prediction tools for selection breeding and elucidation of quantitative trait loci underpinning trait genetic variance. These are typically based on anonymous single nucleotide polymorphism (SNP) markers, which are usually called from, for example, SNP array or sequencing data using a tetraploid model. In this study, we analyzed the impact of using whole genome markers genotyped as either tetraploid or observed allele frequencies from genotype-by-sequencing data on single-trait additive genomic best linear unbiased prediction (GBLUP) genomic prediction (GP) models and single-marker regression genome-wide association studies of potato to evaluate the implications of capturing varying ploidy on the statistical models employed in genomic breeding. A panel of 762 offspring of a diallel cross of 18 parents of elite breeding material was used for modeling. These were genotyped by sequencing and phenotyped for five key performance traits: chipping quality, length/width ratio, senescence, dry matter content, and yield. We also estimated the read coverage required to confidently discriminate between a heterozygous triploid and tetraploid state from simulated data. It was found that using a tetraploid model neither impaired nor improved genomic predictions compared to using the observed allele frequencies that account for true marker ploidy. In genome-wide associations studies (GWAS), very minor variations of both signal amplitude and number of SNPs supporting both minor and major quantitative trait loci (QTLs) were observed between the two data sets. However, all major QTLs were reproducible using both data sets.

Abstract Solanum sisymbriifolium is a shrub native to South America and considered a weed of several important crops. Despite this, this species has proven nematicidal capacity and medicinal properties, due to its ability to produce alkaloids. Thus, the objective of this work was to adjust a reliable protocol to obtain in vitro polyploid plants of S. sisymbriifolium to generate germplasm that serves as the basis for a breeding program of this species aimed to improve the sanitary conditions of horticultural crops with less impact on the environment.

Red clover also known as Trifolium pratense L., is a perennial allogame plant belonging to Trifolium genus and Fabaceae family. Besides its benefits in animal feed and soil improvement, red clover was studied as well for its medicinal properties, being used in different forms like essential oil, tea, pills and other. This study aimed to perform a comparative analysis on some diploid and tetraploid red clover cultivars regarding morphological and biochemical traits. The study was carried out between 2022 and 2023 on 90 red clover cultivars, divided into two samples represented by diploids and tetraploids. Tetraploids were superior to diploids in the 2nd year and inferior in the 3rd year. Regarding the polyphenols content, diploids showed higher values than tetraploids. Between diploids and tetraploids, there was a significant difference in the number of inflorescences/50g and inflorescence weight from the 3rd year.

Abstract Rose (Rosa) is a prominent ornamental plant that holds substantial economic and social significance. Roses originating from different regions exhibit intricate phenotypic and genetic characteristics, but the majority of rose genetic resources are poorly characterized. In this study, 192 genotypes of the genus Rosa were examined using 33 phenotypic traits and 10 pairs of SSR markers. Compared to wild species, both old garden and modern roses exhibited a significant level of diversity, with flower color having the highest degree of diversity and style morphology having the lowest degree of diversity. This phenomenon may be attributed to the limited utilization of wild roses due to their simpler ornamental traits and the frequent phenotypic and molecular infiltration between old garden roses and modern roses. Following a inaugural comprehensive evaluation employing principal component analysis, R. chinensis ‘Zihongxiang’, R. hybrida ‘Burgundy Iceberg’, R. hybrida ‘Conrad F. Meyer’, R. rugosa ‘Gaohong’ and R. floribunda ‘Sheherazad’ were selected as core germplasm resources for future breeding. Moreover, three tetraploid roses, namely R. hybrida ‘Midnight Blue’, R. floribunda ‘Sheherazad’, and R. hybrida ‘Couture Rose Tilia’, with significant differences in both phenotypic and molecular profiles were selected and reciprocally intercrossed. Ultimately, two populations were obtained exhibiting significant variation in flower size, annual stem color, stem pickle density, and leaf number. Furthermore, our results indicated that the traits of flower diameter, flower height, petal width, and petal number may potentially be controlled by two major-effect loci. In conclusion, this study provides novel insights into the evolutionary patterns of Rosa germplasm resources. It paves the way for identifying core genotypes that carry distinct ornamental characteristics and possess immense value for breeding novel varieties in the future.

Abstract Experiments were conducted to optimize triploid induction parameters, and assess triploid sterility, in burbot. Duration and timing of shocks were based on degree minutes, temperature multiplied by time, denoted as °C min. Hydrostatic shock experiments investigated the duration of shock using 7500 or 8500 psi at 180°C min post‐fertilization. Thermal shocks investigated duration of shock and post‐fertilization shock timing using a shock of 16°C. Sterility experiments investigated egg survival when diploids were crossed with triploids. Hydrostatic shock of 7500 psi for 10 or 20°C min can induce triploidy ≥90% and exhibits survival that is statistically similar, p ≤ 0.05, to controls. Hydrostatic shock of 8500 psi for 5 or 10°C min yielded triploid induction of 93% and 100%, respectively, with survival that is statistically similar to controls, p ≤ 0.05. Thermal induction experiments indicated shocks at 120°C min post‐fertilization, for durations between 350 and 450°C min, have potential to induce triploidy ≥90% while facilitating survival statistically similar to controls, p ≤ 0.05. Induction of tetraploidy was observed. Sterility experiments determined that triploid burbot are functionally sterile. These results may allow production of burbot where sterility is required.

Abstract Background Artificial induction of polyploidy is the most common and effective way to improve the biological properties of Populus and develop new varieties of this tree. In this study, in order to confirm and expand earlier findings, we established a protocol using colchicine and based on an efficient shoot regeneration system of leaf blades to induce tetraploidy in vitro in three genotypes from diploid Populus hopeiensis. The stomatal characteristics, leaf blade size, and growth were evaluated for diploids and tetraploids of three genotypes. Results We found that genotype, preculture duration, colchicine concentration, and colchicine exposure time had highly significant effects on the tetraploid induction rate. The optimal protocol for inducing tetraploidy in P. hopeiensis was to preculture leaf blades for 7 days and then treat them for 4 days with 40 mg/L colchicine. The tetraploid induction rates of genotypes BT1, BT3, and BT8 were 21.2, 11.4 and 16.7%, respectively. A total of 136 tetraploids were identified by flow cytometry analysis and somatic chromosome counting. The stomatal length, width, and density of leaf blades significantly differed between diploid and tetraploid plants. Compared with their diploid counterparts, the tetraploids produced larger leaf blades and had a slower growth rate. Our findings further document the modified morphological characteristics of P. hopeiensis following whole-genome duplication (e.g., induced tetraploidy). Conclusions We established a protocol for in vitro induction of tetraploidy from diploid leaf blades treated with colchicine, which can be applied to different genotypes of P. hopeiensis.

[Objectives] This study was conducted to actively carry out the breeding of new tetraploid common buckwheat varieties and its supporting breeding techniques. [Methods] Pintianqiao 3 is a new tetraploid common buckwheat variety developed by CoUege of Agriculture of Shanxi Agricultural University and Agri-cultural Genetic Resources Center of Shanxi Agricultural University, using 'Pintianqiao 1' as the parent, through mutation treatment with 0.2% colchicine aqueous solution, grain selection, plant selection, isolation and identification, variety comparison, regional test and field investigation. The variety has chromosomes 2n = 4X = 32, and shows a spring sowing period of 101 d and a summer sowing period of 80 d, large flowers and seeds & with a 1 000-grain weight of 41.4 g), and good resistance to lodging. [Results] From 2021 to 2022, Pintianqiao 3 participated in the independent joint regional test of common buckwheat varieties in Shanxi Province, and the average yield in 10 test positions was 1.8 kg, equivalent to 1 800 kg/hm², which was 8.4% higher than the control. It passed the field investigation conducted by Shanxi provincial expert group for identification of non-major crop varieties in Dongyang and Kelan experimental sites on September 2 -3, 2022. On January 4, 2024, it passed the preliminary examination of Shanxi Provincial Crop Variety Approval Committee. The seed reproduction technique of Pintianqiao 3 including land selection, preparation before sowing, sowing, field management and timely harvesting has been developed. [Conclusions] This study provides technical support for the demonstration and popularization of this new variety. [ABSTRACT FROM AUTHOR]

Phellodendron amurense Rupr. is a precious medicinal tree species in northeast China. However, P. amurense resources have been severely destroyed due to uncontrolled overharvest and the limited innovation of new germplasms by traditional cross-breeding. In this study, polyploid breeding was introduced to the improvement program of P. amurense. Fifty-four tetraploid plants of P. amurense were first produced by colchicine-induced adventitious bud chromosome doubling in stem segment explants. The induction frequency reached 36.16% (1.0 g L−1 colchicine solution for 48 h treatment) and 50.00% (2.0 g L−1 colchicine solution for 24 h treatment), respectively, showing the high efficiency of the somatic chromosome doubling based on the organogenesis system. Tetraploidization resulted in significant phenotypic variation, such as larger and thicker leaves, thicker stems, and bigger stomata. Ultra-performance liquid chromatography–mass spectrometry (UPLC–MS/MS) analysis identified 59 differentially accumulated alkaloids (DAAs) between the leaf and stem samples of tetraploids, including 32 upregulated and 27 downregulated in stems. For both leaf and stem samples, 18 DAAs were identified between diploids and tetraploids, with 16 DAAs upregulated in tetraploid leaves and 8 upregulated in tetraploid stems, suggesting that polyploidization caused significant alterations in alkaloid contents in leaves and stems of P. amurense. The contents of the main medicinal compounds, such as berberine, jatrorrhizine, phellodendrine, and palmatine, increased significantly in the leaf and/or stem samples after polyploidization. This finding implied that polyploid breeding might be an effective approach for improving P. amurense, beneficial to preserving and exploiting natural resources.

Passiflora edulis Sims (2n = 18) is a perennial plant with high utilization values, but its spontaneous polyploidy in nature has yet to be seen. Thus, this study aims to enhance our understanding of polyploidy P. edulis and provide rudimentary knowledge for breeding new cultivars. In this study, colchicine-induced tetraploid P. edulis (2n = 36) was used as experimental material (T1, T2, and T3) to explore the variances between it and its diploid counterpart in morphology, physiology, and biochemical characteristics, and a comparison of their performance under cold stress was conducted. We measured and collected data on phenotype parameters, chlorophyll contents, chlorophyll fluorescence, photosynthesis, osmotic substances, and antioxidant enzymes. The results showed that tetraploid P. edulis exhibited a shorter phenotype, more giant leaves, darker leaf color, and longer and fewer roots. Moreover, the physiological and biochemical analysis indicated that the tetraploid P. edulis had better photosynthesis systems and higher chlorophyll fluorescence parameters than the diploid P. edulis. Additionally, the tetraploid P. edulis had higher activity of antioxidant enzymes (SOD, POD, CAT) and lower MDA content to maintain better resistance in low temperatures. Overall, we conclude that there were apparent differences in the morphological, physiological, and biochemical traits of the tetraploid and diploid P. edulis. The tetraploid plants showed better photosynthesis systems, higher osmotic substance content, and antioxidant enzyme activity than the diploid, even under cold stress. Our results suggest that tetraploids with more abundant phenotype variation and better physiological and biochemical traits may be used as a new genetic germplasm resource for producing new P. edulis cultivars.

Under salt stress, recretohalophyte Plumbago auriculata tetraploids enhance salt tolerance by increasing selective secretion of Na+ compared with that in diploids, although the mechanism is unclear. Using non-invasive micro-test technology, the effect of salt gland Ca2+ content on Na+ and K+ secretion were investigated in diploid and tetraploid P. auriculata under salt stress. Salt gland Ca2+ content and secretion rates of Na+ and K+ were higher in tetraploids than in diploids under salt stress. Addition of exogenous Ca2+ increased the Ca2+ content of the salt gland in diploids and is accompanied by an increase in the rate of Na+ and K+ secretion. With addition of a Ca2+ channel inhibitor, diploid salt glands retained large amounts of Ca2+, leading to higher Ca2+ content and Na+ secretion rate than those of tetraploids. Inhibiting H2O2 generation and H+-ATPase activity altered Na+ and K+ secretion rates in diploids and tetraploids under salt stress, indicating involvement in regulating Na+ and K+ secretion. Our results indicate that the increased Na+ secretion rate of salt gland in tetraploids under salt stress was associated with elevated Ca2+ content in salt gland.