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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]

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]

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]

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]

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.

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]

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.

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.

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 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.

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.

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.

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.

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.

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.

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.

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.

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.

Triploid Crassostrea angulata has the advantages of fast growth, poor fertility and high quality. However, due to poor fertility, direct genetic improvement is difficult. Mating between tetraploid males and diploid females has been shown to be the best method for commercial triploid production, so genetic improvement of tetraploids will directly affect the phenotypic traits of triploid offspring. However, to date, few studies have investigated the genetic improvement of tetraploid oysters. Based on the induced tetraploid C. angulata population, this study carried out three successive generations of growth selective breeding research, and systematically compared the growth, survival, ploidy composition and sex ratio of the selected group and the control group. The results showed that there was no significant difference in the survival rate from planktonic larvae to adult between the two groups. However, the growth of the selected group was significantly higher than that of the control group, that was, the shell height and whole weight of S3 were significantly higher than that of C3, and the selection advantage of shell height increased from 7.80% of S1 to 34.68% of S3. The ploidy composition of the two tetraploid groups was relatively stable before the 90th days, but on the 270th day, some tetraploids underwent chromosome loss and transformed into diploids or triploids, which might be related to gametogenesis of tetraploids. Moreover, with the increase of generations, the number of individuals with chromosome loss in the selected group gradually decreased, and their ploidy became more stable than that in the control group. In addition, both groups were fertile, with a sex ratio of more males than females, and a proportion of hermaphrodite individuals. In conclusion, this study successfully selected a fast growth line of tetraploid C. angulata , which can be used for commercial production of fast-growing triploid C. angulata , and provides a basis and reference for the genetic improvement of tetraploid oysters. • Firstly carried out the genetic improvement of tetraploid C. angulata by selective breeding. • The growth traits of selected groups were significantly improved than those of control group. • Both groups underwent ploidy conversion, but the selected group had a relatively more stable ploidy. • The selected tetraploids were fully fertile and present many males and hermaphrodite individuals. • This study provided excellent parental sources for commercial production of fast growth triploids. [ABSTRACT FROM AUTHOR]

Triploids have received increasing attention in the industrialization of oysters due to their fast growth rate, tolerance, and their sterility to be marketed year-round. Cultivating varieties or lines with special colors could be crucial for germplasm enrichment as well as traceability and intellectual property protection during the commercialization process. However, triploids and tetraploids with special colors have not been studied in the Fujian oyster Crassostrea angulata , which has seriously limited their commercialization and scalability. In this study, diploid and tetraploid C. angulata with normal, golden and black shell colors were used as parents and their corresponding triploids were constructed. The growth and survival of the nine groups were comprehensively evaluated during the larval and grow-out stages. Sex ratio, ploidy composition and thermotolerance were also statistically compared. All three triploid groups (NDT, GDT and BDT) exhibited significant advantages in growth and survival, compared to their diploid (NDD, GDD and BDD) and tetraploid (NTT, GTT and BTT) counterparts in all three sites. The triploid advantages in survival rate among NDT, GDT and BDT were 38.36%, 40.38% and 36.00%, respectively, at Jiaonan at day 480. Moreover, higher thermotolerances were exhibited in NDT, BDT and GDT, with the values of LT 50 at 41.77 °C, 42.28 °C and 42.13 °C, respectively. On the contrary, the three tetraploid C. angulata lines (NTT, GTT and BTT) exhibited poor growth, survival and thermotolerances. The values of LT 50 for GTT and NTT were comparable and lower than this of BTT (GTT: 39.85 °C; BTT: 41.05 °C; NTT: 39.57 °C). It is encouraging to note that the tetraploid rates also remained above 80% at day 480 in all three tetraploid lines. Based on our study, the three triploid C. angulata lines with normal, black, and golden shell colors showed great potential and can be industrialized as new varieties to improve the oyster industry. However, the inferior performance of tetraploids should not be overlooked and demands extra concern in the future breeding process. • We firstly constructed diploid, triploid and tetraploid Crassostrea angulata with normal, golden and black shell colors. • Significant triploid advantages in survival, growth and thermotolerance were observed among all three triploid lines. • The tetraploid rates also remained above 80% at day 480 in all three tetraploid lines. • The significant advantages of triploids and the inferior performance of tetraploids cannot be overlooked in the breeding process. [ABSTRACT FROM AUTHOR]

The application of cold shock to inhibit the extrusion of the second polar body in fertilized eggs is one of the main methods to induce triploid in diploid fish. In this study, we originally planned to induce hexaploid by this method in tetraploid carp. However, among the surviving offspring, we observed only 50.7% tetraploid and 49.3% diploid individuals, which could potentially result from either androgenetic diploids or gynogenetic diploids. The absence of irradiation and the high proportion of diploids attracted us. However, the lack of sex-specific markers for tetraploid carp, makes it difficult to determine their origin. Fortunately, we also carried out the cross of yellow carp (Cyprinus carpio yellow var., 2n, ♀) × tetraploid carp (♂) and red crucian carp (Carassius auratus red var., 2n, ♀) × tetraploid carp (♂) with cold shock inhibiting the second meiosis, diploid offspring have also been found, and whether they have undergone gynogenesis or androgenesis can be judged based on phenotype and genotype. In terms of phenotypes, the key phenotypes of two diploids, such as the whisker length, number of lateral scales, and presence of melanin, are consistent with tetraploid carp. In terms of genotypes, through single-copy nuclear gene cloning and fluorescence in situ hybridization (FISH), it is supported that both diploids are androgenetic offspring. In addition, 14.9% of tetraploid offspring were found in red crucian carp (♀) × tetraploid carp (♂) with cold shock inhibiting the second meiosis. By the above-mentioned means of detection, it was found that they were created by inhibiting the extrusion of the second polar body of the fertilized eggs. From this it will be seen that the application of cold shock before the extrusion of the second polar body of fertilized eggs cause not only polyploidy, but also the elimination of both second polar body and female nucleus. Previous studies have found that cold shock can induce lethal androgenetic haploids in diploid fish, but these androgenetic diploid fish produced by tetraploid carp sperm were surviving. We summarize the mechanism behind the above phenomenon, which is mainly related to meiosis occurring at the edge of the cell membrane. Cold shock may disrupt the function of the spindle, resulting in the simultaneous retention or extrusion of female nucleus and second polar body. This study will provide valuable insights into androgenesis, polyploidization, and hybridization in fish genetic breeding. • Androgenetic diploids were induced from tetraploid carp sperm by cold shock without irradiating the eggs. • New-type allotetraploids were induced in the cross between male tetraploid carp and female diploid carp by cold shock. • Nuclear gene cloning is suitable for qualitative analysis of the genetic composition of hybrids, but not for quantitative analysis. [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 PfrFAD3a through a large deletion. Simultaneous knockout of two copies of FATTY ACID DESATURASE 3 (PfrFAD3a and PfrFAD3b) 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 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., (© The Author(s) 2024. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site–for further information please contact journals.permissions@oup.com.)

The article focuses on the development and release of the new cultivar Vaccinium ovatum 'Cascade Jewel,' which is an evergreen shrub native to the Pacific Northwest, prized for its compact growth and ornamental value. Topics include the breeding process involving induced polyploidy, selection criteria for improved growth habit, and the description of 'Cascade Jewel' including its compact growth, floriferous nature, and fruit characteristics.

Tetraploid oysters hold a significant position in the global oyster industry, particularly as core germplasm resources for the production of triploids. Triploids exhibit desirable characteristics such as reduced gonadal development, larger adult size, and superior flesh quality compared with diploids. However, tetraploids often face challenges of slow growth and chromosomal instability during the breeding process, and the mechanisms underlying the formation of these polyploid characteristics remain unclear. This study aimed to elucidate these mechanisms by constructing a polyploid oyster system and comparing the differences in growth-related phenotypes and gene expression among diploids, triploids, and tetraploids. We identified 1404 differentially expressed genes (DEGs) between diploids and triploids, 1814 DEGs between triploids and tetraploids, and 933 DEGs between diploids and tetraploids. Furthermore, we observed distinct gene expression patterns related to innate immunity response and biomineralization between different ploidy levels. Through trend analysis, we clustered genes with similar expression level changes across different ploidy levels and conducted gene ontology (GO) enrichment analysis on genes with different expression profiles. The results indicated that genes associated with the innate immunity response exhibited significantly upregulated expression with increasing ploidy, while genes related to biomineralization showed higher or lower expression levels in triploid oysters. As biomineralization is closely linked to oyster shell growth, this highlights the crucial role of genes associated with biomineralization in regulating the rapid shell growth observed in triploid oysters. Confronted with environmental challenges, tetraploid oysters may display a stronger innate immune response than diploids and triploids. Our study provides valuable resources for investigating the functional aspects of genes related to polyploid phenotype differences and offers new insights into the molecular mechanisms of existing issues in tetraploid oyster breeding. • Triploid oysters show enhanced calcium transport, regulation, and protein degradation. • Chromosomal duplication affects polyploid oysters' growth and adaptability. • Gene replication exhibits detrimental dosage effects following duplication. [ABSTRACT FROM AUTHOR]

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., (© 2024. The Author(s).)

Polyploid fish have valuable applications in aquaculture, and artificial breeding of polyploids is an important field of aquatic research. In this study, fertilized eggs (65–100 min post-fertilization (mpf)) were treated with 650–750 kg/cm2 hydrostatic pressure for 3–6 min to induce tetraploidy. The optimal rates for hatching and tetraploidization of embryos were achieved at 4.70% and 23.33%, correspondingly. Flow cytometry analysis revealed that the DNA content of tetraploidized embryo cells was approximately twice that of the wild-type. The chromosome number of the tetraploidized rice field eels was 48. In this study, artificially induced tetraploid rice field eels were able to survive, with four of them reaching 20 months of age. Measurement of erythrocyte nuclei revealed that the nuclear area of erythrocytes from tetraploids increased and was approximately twice that of the diploids. Histological analysis showed that the gonads of tetraploids developed into testes, and spermatogenetic germ cells were observed. In conclusion, a technique to induce tetraploidization has been developed for rice field eels by applying 700 or 750 kg/cm2 hydrostatic pressure on 85 mpf embryos for 5 min. The viable tetraploidized rice field eels were produced using this approach. • A method for hydrostatic pressure shock-induced tetraploid rice field eel was established. • Artificially induced tetraploid rice field eels survived and grow up to adult. • The gonad of tetraploid rice field eel developed into testis and may be fertile. [ABSTRACT FROM AUTHOR]

• Tetraploid elsholtzia splendens was obtained by colchicine induction for the first time. • A rapid and effective method was established for tetraploid induction in E. splendens. • Biomass increase were mainly effected by photosynthesis and cell differentiation. • LOB regulator was the most key factor resulting in significant increase of biomass. • Proposing response model for the regulatory mechanism of tetraploid biomass increase. Elsholtzia splendens is an ideal plant species for remediating copper-contaminated soils. However, its application range is regrettably hindered by its generally low biomass and rather narrow range of suitable growing conditions. Polyploid technique is a shortcut to enhance biomass and environmental adaptability of plant, which may become an important breakthrough to improve application value of E. splendens. In this study, tetraploid E. splendens (2n = 4x = 32) was successfully obtained from wild E. splendens (2n = 2x = 16) using a primary meristem processing technique for the first time, exhibiting a huge biomass advantage. In order to find out the underlying mechanism for its huge biomass advantage, a series of difference assessments between two ploidy-level E. splendens were performed, including morphological, anatomical, physiological, photosynthesis, transcriptome and endogenous hormones experiments. All the results consistently showed that enhanced photosynthesis and alterated cell differentiation function drove significant biomass increase. During the process of excavating molecular mechanism deeply, five hub genes (regulating Rubisco, light-harvesting chlorophyII a/b-binding protein 2 (Lhcb2), photosystem I subunit PsaO (PsaO), magnesium protoporphyrin IX methyltransferase (ChlM) and lateral organ boundaries (LOB) domain (LBD)) were found to play extremely vital roles in biomass increase regulation. Especially, LOB may be the most key factor resulting in the transformation of E. splendens from a single plant to a cluster, ultimately leading to biomass multiplication. Finally, a responsive model was proposed to elucidate the regulatory mechanisms of huge biomass in the tetraploid E. splendens. The present findings provide new evidence for understanding the complex regulatory networks responsible for remarkable biomass increase in polyploid plants. [Display omitted] [ABSTRACT FROM AUTHOR]

It is crucial to clarify the physiological responses of wheat (T. aestivum) plants to source-sink manipulation and assimilation transportation under drought stress during domestication of dryland wheat. In this research, a two-year field experiment was conducted using nine wheat cultivars in a semiarid site of northwest China. The source-sink manipulation treatments including defoliation of flag leaves and 50% removal of ears were applied at the anthesis stage under two levels of drought stress conditions i.e. progressive water supply (PWS) and rainfed drought treatment (RDT). Our results indicated that drought stress reduced the dry weight of leaves, sheaths and stems, as well as caused a significant yield reduction. High ploidy wheat exhibits a greater capacity to sustain higher grain yields when subjected to drought stress, primarily due to its stronger buffer capacity between source supply and sink demand. All wheat species with different ploidy levels had a certain degree of source limitation and sink restriction. During the domestication of wheat, the type of source and sink might be ploidy-dependent with progressive water deficit, but similar interactive relationships. The source-sink ratio of tetraploid species was the largest, while that of hexaploid species was the lowest. • Progressive water supply (PWS) mediated source-sink relation in wheat. • High ploidy wheat had higher grain yield than low one under drought stress. • It was due to stronger buffer capacity between source supplies and sink demand. • Source-sink ratio was the highest in tetraploid, and the lowest in hexaploid. • All ploidy wheat showed certain degree of source limitation and sink restriction. [ABSTRACT FROM AUTHOR]

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 Ca 2+ content on Na + and K + secretion were investigated in diploid and tetraploid P. auriculata under salt stress. Salt gland Ca 2+ content and secretion rates of Na + and K + were higher in tetraploids than in diploids under salt stress. Addition of exogenous Ca 2+ increased the Ca 2+ 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 Ca 2+ channel inhibitor, diploid salt glands retained large amounts of Ca 2+ , leading to higher Ca 2+ content and Na + secretion rate than those of tetraploids. Inhibiting H 2 O 2 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 Ca 2+ content in salt gland., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Duan, Jiang, Lei, Ouyang, Liu, Zhao, Li, Yang, Li, Yi and Gao.)