Diploid Progeny Research Articles

Identification of Resistance QTLs to Black Leaf Streak Disease (Due to Pseudocercospora fijiensis) in Diploid Bananas (Musa acuminata)

Black Leaf Streak Disease (BLSD), caused by the fungus Pseudocercospora fijiensis, is a recent pandemic and the most economically and environmentally important leaf disease of banana. To assist breeding of varieties with durable resistance to the rapidly evolving P. fijiensis, we used a diploid genitor ‘IDN 110’ with partial resistance to BLSD to search for QTLs. We assessed diploid progeny of 73 hybrids between ‘IDN 110’ and the diploid cultivar ‘Khai Nai On’, which is susceptible to BLSD. Hybrids were phenotyped with artificial inoculation under controlled conditions. This method allowed us to focus on resistance in the early stages of the interaction already identified as strongly influencing BLSD epidemiology. Progeny were genotyped by sequencing. As both parents are heterozygous for large reciprocal translocations, the distribution of recombination was assessed and revealed regions with low recombination rates. Fourteen non-overlapping QTLs of resistance to BLSD were identified of which four main QTLs from the ‘IDN110‘ parent, located on chromosomes 06, 07, 08, and 09, were shown to be of interest for marker-assisted selection. Genes that underline those four QTLs are discussed in the light of previous literature.

Broadening the genetic base of the diploids with biotic resistance to accelerate banana (Musa acuminata L.) breeding

Success of banana (Musa acuminata L.) breeding mainly depends on the male diploid parents used in the hybridization program. Developing intermediate diploid breeding lines with fertile pollen production ability, resistance to biotic and abiotic stresses, and fruit quality through the diploid x diploid strategy is the key step in improving commercial cultivars. Till now, at the global level only a limited number of diploid accessions is being used in banana breeding programs. In the present study, through the diploid x diploid breeding strategy, the genetic diversity of diploids has been broadened by developing nine polleniferous biotic-stress-resistant diploid lines. Among these, except for two progenies (P), all were resistant to the eumusae leaf spot disease. A single progeny (P 134) showed resistance to root-lesion and root-knot nematodes, whereas P 148 showed moderate resistance to root-knot nematodes alone. Three progenies of cv. Rose x Pisang Lilin (P 427, P 428 and P 429) were moderately resistant to banana stem weevil. Irrespective of cross combinations, barring two, all other progenies exhibited resistant reactions to fusarium wilt, Foc race 1 under both hot spot and pot culture screening. Among the nine diploid progenies, P 427, P 428 and P 429 were the best prospects to contribute multiple resistance against pests (banana stem weevil) and diseases (eumusae leaf spot and Foc race 1), whereas P 134 could be used as the resistant source for root-knot nematodes. The pyramiding of resistant/defense-related alleles in the progenies has been confirmed through SSR markers associated with Foc resistance. These polleniferous resistant improved diploid progenies are the potential source for accelerating the banana breeding program for improving biotic resistances in the triploid commercial cultivars through reconstructive breeding and/or for stacking the resistant genes in other genetic backgrounds.

Comparative genomics of Leishmania donovani progeny from genetic crosses in two sand fly species and impact on the diversity of diagnostic and vaccine candidates.

Sand fly transmitted Leishmania species are responsible for severe, wide ranging, visceral and cutaneous leishmaniases. Genetic exchange can occur among natural Leishmania populations and hybrids can now be produced experimentally, with limitations. Feeding Phlebotomus orientalis or Phlebotomus argentipes on two strains of Leishmania donovani yielded hybrid progeny, selected using double drug resistance and fluorescence markers. Fluorescence activated cell sorting of cultured clones derived from these hybrids indicated diploid progeny. Multilocus sequence typing of the clones showed hybridisation and nuclear heterozygosity, although with inheritance of single haplotypes in a kinetoplastid target. Comparative genomics showed diversity of clonal progeny between single chromosomes, and extraordinary heterozygosity across all 36 chromosomes. Diversity between progeny was seen for the HASPB antigen, which has been noted previously as having implications for design of a therapeutic vaccine. Genomic diversity seen among Leishmania strains and hybrid progeny is of great importance in understanding the epidemiology and control of leishmaniasis. As an outcome of this study we strongly recommend that wider biological archives of different Leishmania species from endemic regions should be established and made available for comparative genomics. However, in parallel, performance of genetic crosses and genomic comparisons should give fundamental insight into the specificity, diversity and limitations of candidate diagnostics, vaccines and drugs, for targeted control of leishmaniasis.

Heat stress promotes haploid formation during CENH3-mediated genome elimination in Arabidopsis.

Impaired activity of centromeric histone CENH3 causes inaccurate chromosome segregation and in crosses between the Arabidopsis recombinant CENH3 mutant GFP-tailswap and CENH3G83E with wild-type pollen it results in chromosome loss with the formation of haploids. This genome elimination in the zygote and embryo is not absolute as also aneuploid and diploid progeny is formed. Here, we report that a temporal and moderate heat stress during fertilization and early embryogenesis shifts the ratio in favour of haploid progeny in CENH3 mutant lines. Micronuclei formation, a proxy for genome elimination, was similar in control and heat-treated flowers, indicating that heat-induced seed abortion occurred at a late stage during the development of the seed. In the seeds derived from heat-treated crosses, the endosperm did not cellularize and many seeds aborted. Haploid seeds were formed, however, resulting in increased frequencies of haploids in CENH3-mediated genome elimination crosses performed under heat stress. Therefore, heat stress application is a selective force during genome elimination that promotes haploid formation and may be used to improve the development and efficacy of in vivo haploid induction systems.

Synthetic apomixis with normal hybrid rice seed production

Synthetic apomixis with normal hybrid rice seed production

Survival and growth of triploid eastern oysters, Crassostrea virginica, produced from wild diploids collected from low-salinity areas

Triploid Eastern oysters have been reported to suffer greater mortalities than diploids when exposed to low-salinity (<5) conditions in the U.S. Gulf of Mexico and Atlantic estuaries. As such, the effect of broodstock parentage was investigated on the low-salinity tolerance of triploid progeny produced by mating diploid females (collected from three Louisiana estuaries differing in salinity regimes) with male tetraploids at two hatcheries. Diploid crosses were also produced using the wild broodstocks to verify expected differences in low-salinity tolerance among diploid progeny and between ploidy levels. All progeny were deployed at low and moderate-salinity (averages of 9.3 and 19.4) field sites to monitor monthly growth and mortality. Sex ratio, gametogenic stage, gonad-to-body ratio, condition index, and Perkinsus marinus infection were also measured periodically at both field sites Although high triploid mortality at the low-salinity site prevented complete analysis, results indicated that diploid parentage had little effect on triploid survival at low salinity. Broodstock parentage affected diploid mortality and growth, although results did not match with predictions made based on historical salinity at broodstock collection sites. Ploidy level had the largest effect on triploid survival and growth followed by the hatchery site where the oysters were produced.

Phenotypic diversity, growth and sexual differentiation in the progeny of wild Kappaphycus alvarezii (Gigartinales, Florideophyceae)

ABSTRACT Wild and fertile Kappaphycus alvarezii, both cystocarpic gametophytes and tetrasporophytes, were collected for in vitro spore release and cultivation. Six parental individuals with distinct phenotypes, i.e. variable colour and morphology, were selected. Growth rates of the corresponding diploid tetrasporophyte and haploid gametophyte progeny did not vary significantly. The mature tetrasporophytes growing from carpospores exhibited mostly green, brown and bicolour (green and brown) individuals – colours inherited from their parents. Conversely, the resulting gametophytes growing from tetraspores produced multicoloured individuals, or individuals with yellow, green, brown, grey, black, orange and red colouration. Sexual ambiguity was resolved on the eighth month with more females than males. Plants arising from single basal discs were observed to exhibit distinct colours in different branches and monoecious individuals with male and female reproductive structures were observed in different branches. Our study showed that wild populations and their progenies are a good source of new strains for future farming.

Length-weight Relationship of Heterobranchus bidorsalis (Geoffroy st. Hilaire 1809) Diploid and Triploid Progenies raised under the same Environmental condition

Twenty specimens of triploid with weight and length ranging from 207-300g and 29-32cm; diploid 150-200g and 23-28cm Heterobranchus bidorsalis (Geoffroy St. Hilaire 1809) were subjected to morphometric and meristic characterization, length-weight relationship and condition factor evaluation. Triploid specimens had the higher values in all the parameters examined and were significantly different (P&lt;0.005). Regression analysis of diploid and triploid show the ranges of values (K) of 0.802 1.453 and 0.838 0.906 respectively, for condition factor (k) while the relative condition factor values (Kn) ranged between 0.869 1.087 and 0.968 1.038 respectively. Weight increases directly as the total length increases for both diploid and triploid indicating isometric growth. The R2 in triploid was higher (96.8%) than in diploids (42.4%). In diploid progenies, the length by weight was significantly different (P&lt;0.05) in triploid. Triploid progenies need no special adaptive environment or technique for rearing. Therefore, diploid and triploid progenies can be successfully cultured simultaneously under the same environmental condition.

Alien introgression and morpho-agronomic characterization of diploid progenies of Solanum lycopersicoides monosomic alien addition lines (MAALs) toward pre-breeding applications in tomato (S. lycopersicum)

Key messageAlien introgressions that were captured in the genome of diploid plants segregating from progenies of monosomic alien addition lines of S. lycopersicoides confer novel phenotypes with commercial and agronomic value in tomato breeding.Solanum lycopersicoides is a wild relative of tomato with a natural adaptation to a wide array of biotic and abiotic challenges. In this study, we identified and characterized diploid plants segregating from the progenies of monosomic alien addition lines (MAALs) of S. lycopersicoides to establish their potential as donors in breeding for target trait improvement in tomato. Molecular genotyping identified 28 of 38 MAAL progenies having the complete chromosome complement of the cultivated tomato parent and limited chromosome introgressions from the wild S. lycopersicoides parent. Analysis of SSR and indel marker profiles identified 34 unique alien introgressions in the 28 MAAL-derived introgression lines (MDILs) in the genetic background of tomato. Conserved patterns of alien introgressions were detected among sibs of MDILs 2, 3, 4 and 8. Across MDILs, a degree of preferential transmission of specific chromosome segments was also observed. Morphologically, the MDILs closely resembled the cultivated tomato more than S. lycopersicoides. The appearance of novel phenotypes in the MDILs that are lacking in the cultivated parent or the source MAALs indicates the capture of novel genetic variation by the diploid introgression lines that can add commercial and agronomic value to tomato. In particular, screening of representative MDILs for drought tolerance at the vegetative stage identified MDIL 2 and MDIL 11III as drought tolerant based on visual scoring. A regulated increase in stomatal conductance of MDIL 2 under drought stress indicates better water use efficiency that allowed it to survive for 7 days under 0% moisture level.

First Report on Successful Triploidy Induction in Clarias gariepinus (Burchell, 1822) Using Electroporation

This study investigated the use of electric-shock in inducing triploidy in African catfish Clarias gariepinus. To achieve this, three voltages (9, 12, 21 V) were applied for different durations (3, 5, 10 min). The shock was initiated approximately three minutes after fertilization followed by incubation in ambient temperature. After incubation, hatchability and survival rates were determined while ploidy status of the treatment fishes was confirmed in one-month-old fingerlings using the exclusive triploid range of the erythrocyte major axis previously reported for the same species (11.9–14.9 μm) and by cytogenetic analysis of the chromosome. The results showed triploidy were achieved in 10 to 85% of the treatment groups. A consistent trend of decrease in hatchability and an increase in triploidy rate was observed with increased electroporation voltages and shock durations. The mean erythrocyte major axis length of triploid progenies (3n = 84) was observed to be between 11.3–14.6 μm and was higher than the range of 7.0–10.5 μm recorded for diploid progenies (2n = 56). It was concluded that electric shock can be used to induce triploidy in African catfish C. gariepinus.

Study on artificial induction, growth and gamete quality of mitogynogenetic turbot Scophthalmus maximus

Artificial gynogenesis induction is one of the important techniques of chromosome manipulation. The eggs are fertilized with inactivated sperm to prevent the inheritance from the paternal genome, and genome information of the offspring is totally contributed by the maternal genome. Mitogynogenesis, in which diploidization of chromosome set is performed by blocking the cleavage, is theoretically homozygous and has got more attention in breeding. In this study, we performed the mitogynogenetic diploid induction in turbot Scophthalmus maximus, one of the most important maricultural fish in China and Europe, by applying hydrostatic pressure to the eggs activated with UV-irradiated homologous sperm. The optimal inducing conditions were 36,000 erg mm-2 for UV-irradiated and pressure of 65 MPa for 6 min at 15 min before the appearance of the cleavage furrow. Two mitogynogenesis stocks were obtained in 2016 and 2017. The results showed that there was no distinct difference in incubation time and morphological traits between mitogynogenetic diploid and control diploid. The survival rates of mitogynogenetic diploid sharply decreased in the first month post hatching (mph). Their total weight (tW) and total length (tL) increased rapidly from 12 to 18 mph. The mitogynogenetic diploids induced in 2016 and 2017 showed very different growth. The mean tW and tL of 10 fast-growing individuals at 18 mph were 2.78 and 1.32 times of the others in 2016 stock, while 4.50 and 1.74 times in 2017 stock, respectively. The higher male ratio and rising trend of male ratio indicated the female heterogametic ZW/ZZ genetic mechanism of sex determination in turbot. Twenty-four adults in 2017 stock survived until 24 mph. While twenty-nine adults in 2016 stock survived until 36 mph, in which 11 adults could be promoted mature. Then the qualities of gametes were evaluated and showed that both the egg and the sperm qualities of mitogynogenetic diploid were lower than those of control diploid. However, the embryo and larvae development showed no difference between mitogynogenetic diploid progeny and control diploid.

Meiotic gynogenesis with heterologous sperm in the mandarin fish Siniperca chuatsi and evidence for female homogamety

The mandarin fish Siniperca chuatsi is a historically important aquaculture species in China and exhibits sexually dimorphic growth. However, sex determination of this fish remains unclear so far. In this study, we induced meiotic gynogenesis in S. chuatsi using irradiated heterologous sperm from spotted mandarin fish (Siniperca scherzeri) to uncover its mechanism of sex determination. Up to 7.52% diploid progeny were obtained among three gynogenetic families in this study. Molecular analysis of female and male donors and sampled young gynogens by seven microsatellite loci further confirmed no genetic contributions from the ‘father’ S. scherzeri. After 8 months of culture, external morphology of adult fish showed that all gynogens were cloned from their mothers. Gonads of the gynogenetic progeny were examined by histological observations and the sexing results showed that they were almost 100% females, strongly supporting an assumption of female homogamety in mandarin fish. By this study, we obtained pure lines of S. chuatsi and elucidated its genetic mechanism of sex determination, providing a basis for possible sex control breeding in this species.

Genomic Instability in Cancer II: 4N-Skewed (90&amp;#176;) Reductive Division via Fragile Sites to Fitness Increase for Solid and Hematological Cancer Beginnings

The objective herein was to connect the ontogeny process of diplochromosomal, amitotic, 4n-skewed division-system, to cytogenetic deficiency lesions in satellite, repetitive DNAs, especially in the chromosomal fragile sites, some 100 distributed over the genome. These latter studies had shown that chemical induced replication-stress led to un-replicated lesions in these fragile sites, which from inaccurate repair processes caused genomic instability. In the chain of events of the ontogeny process to the special tetraploidy, it was proposed that primary damaged human cells could undergo replication stress from repair-process present during cell replication, a suggestion verified by X-ray damaged cells producing the unstable fragile sites (see text). The cancer-importance for therapy is recognition of cell cycle change for the 4n derivative fitness-gained, diploid progeny cells. An open question is whether RB controlling G1 to S-period is mutated at this suggested tumorigenesis initiating phase, and if so, with what consequences for therapy. The fragile site studies further showed that repair of repetitive DNAs could produce two types of genomic changes: single gene mutations and CNVs, which were here shown to be chromosomally located on “borders” to repairing satellite lesions. This genomic placement was found to correspond to mutations identified in tumor sequencing (p53, Rb, MYC), favoring a bad luck location for their cancer “mutational nature”. The CNVs in cancers, are here seen as molecular expressions of long-known cytogenetic HSRs and DMs also with demonstrated origin from amplifications of single genes. Over-expression of oncogenes was hinted of being from duplications, but Drosophila genetics demonstrated the opposite, gene inactivation. The reduced eye-size from dominant, BAR-Ultra-Bar-eye phenotypes, was caused by duplications, inactivating the genetic system for eye-size. The finding of CNVs showing “evasion” of the immune system suggests, inactivation of immune-determining genetics. Since mutated genes on borders to satellite DNAs are a fact in hematological cancers, the 4n-skewed division-system is suggested to replace debated leukemogenesis with fitness-gain from molecular mutations. For these cancers the question is how normal bone marrow cells attain genomic damage for special tetraploidy, which was referred to studies of cells moving in artificial marrow-like substrate, needing serious attention.

Can obligate apomixis and more stable reproductive assurance explain the distributional successes of asexual triploids in Hieracium alpinum (Asteraceae)?

Although reproductive assurance has been suggested to be one of the most important factors shaping the differential distributional patterns between sexuals and asexuals (geographic parthenogenesis), it has only rarely been studied in natural populations of vascular plants with autonomous apomixis. Moreover, there are almost no data concerning the putative relationship between the level of apomictic versus sexual plant reproduction on one hand, and reproductive assurance on the other. We assessed the level of sexual versus apomictic reproduction in diploid and triploid plants of Hieracium alpinum across its distributional range using flow cytometric analyses of seeds, and compared the level of potential and realized seed set, i.e. reproductive assurance, between the two cytotypes under field and greenhouse conditions. Flow cytometric screening of embryos and endosperms of more than 4,100 seeds showed that diploids produced solely diploid progeny sexually, while triploids produced triploid progeny by obligate apomixis. Potential fruit set was much the same in diploids and triploids from the field and the greenhouse experiment. While in the pollination-limited environment in the greenhouse apomictic triploids had considerably higher realized fruit set than sexual diploids, there was no significant difference between cytotypes under natural conditions. In addition, sexuals varied to a significantly larger extent in realized fruit set than asexuals under both natural and greenhouse conditions. Our results indicate that triploid plants reproduce by obligate apomixis, assuring more stable and predictable fruit reproduction when compared to sexual diploids. This advantage could provide apomictic triploids with a superior colonisation ability, mirrored in a strong geographic parthenogenesis pattern observed in this species.

Viable diploid progeny induced from sperm of Chinese tetraploid pond loach by cold-shock androgenesis

Natural tetraploid loach (Misgurnus anguillicaudatus) living in the Changjiang River basin and adjacent area in China has been considered a true genetic tetraploidy (4n = 100) with four sets of homologous chromosomes. Here, we reported its further supporting evidence provided by the cold-shock androgenesis. Viable androgenetic progeny appeared when eggs were cold-shocked at 3°C for 60 min, starting 5 min after fertilization with sperm of natural tetraploid males, although the survival rate was significantly lower than control group. The majority (87%) of androgenetic embryos were diploid (2n = 50) and all-paternal inheritance was verified in larval stage by microsatellite genotypes. Microscopic observations confirmed the elimination of both egg nucleus and second polar body from a fertilized egg, followed by the cleavage exclusively with sperm nucleus. Thus, the appearance of normal diploid androgenetic progeny from sperm of natural tetraploid loach revealed the presence of four chromosome sets in tetraploid males.

Genomic Instability in Cancer I: DNA-Repair Triggering Primitive Hereditary 4n-Skewed, Amitotic Division-System, the Culprit in EMT/MET/Metaplasia Cancer-Concepts

The objective was to gain proof of genome damage-repair induced mitotic slippage process (MSP) to 4n-diplochromosome skewed division-system, earlier suggested to have “cancer-deciding” consequences. Our damage-model showed two succeeding phases: molecular mutations for initiation of fitness-gained cells, and large chromosomal changes to aneuploidy from inherited DNA-breakage-repair inaccuracies. The mutations were gained while DNA-repair and DNA-replication, co-existed in the route to tetraploidy, a phenomenon also expressed for some existing unicellular organisms. These organisms also showed genome reductive, amitotic, meioticlike division, and was the origin of human genome conserved, self-inflicted 90° reorientation of the 4n nucleus relative to the cytoskeleton axis. In the in vitro DNA-damage model, this remarkable 4n-event deciding “flat-upright” cell-growth characteristics showed several consequences, for example, cancer-important, E-cadherin-β-catenin cell-to-cell adherence destruction, which gave diploid progeny cells, mobility freedom from cell contact inhibition, likely in renewal tissues. This 4n-skewed division-system with inheritance in progeny cells for repeat occurrences as mentioned for flat-up-right growth patterns is similar to claimed concepts of metaplasia-EMT/MET embryogenesis events in cancer evolution. A scrutiny of this literature, proof-wise invalidated this embryological concept by tetraploid 8C cells occurring in MET events and, was noted for small cell occurrence, i.e., diploidy from 4n-8C reductive division, an also event for tumor relapse cells, derived from genome damaging therapy agents. Pre-cancer hyperplasia reported MSP, cadherincatenin destruction and 90° perpendicularity to basal cell membrane. The DNA-damage-repair model can weed-out therapy-agents triggering 4n-skewed division. Cancer-control, beginning-information, is likely from mutational identity of the 4n derived fitness-gained cells.

Impact of the Leaf Cut Callus Development Stages of Populus on the Tetraploid Production Rate by Colchicine Treatment

This paper examined the impact of the leaf incision callus developmental status of Populus on the tetraploid production efficiency. Using diploid full-sib progeny [(Populus pseudo-simonii × P. nigra ‘zheyin3#’) × (P. × beijingensis)] as experimental material, leaf explants were gathered from seedlings of five genotypes selected randomly from full-sib hybrid progeny cultured in Murashige and Skoog basal medium with 0.4 mg/L 6-benzyladenine and 0.05 mg/L 1-naphthaleneacetic acid. The morphological and cytological characteristics of the incision callus (from the callus origin and adventitious bud development) were observed and divided into five stages based on the characteristics of the callus. The incision callus from each of the five stages was treated with 30 mg/L colchicine for 3 days. Then, the polyploidy level of the regenerated plants was confirmed by flow cytometry analysis and chromosome number counting. The results indicate that the rate of tetraploid production was significantly correlated with the callus development stage of Populus leaves; the most likely stage for chromosome doubling was Stage II, in which the calli initially formed around the cut end. To validate that callus developmental Stage II was the optimal callus developmental stage for chromosome doubling of diploid full-sib progeny, ten full-sib progeny genotypes were treated with 30 mg/L colchicine for 3 days at Stage II. All ten genotypes of the diploid progeny obtained tetraploid with no mixoploid production; the percentage of tetraploid induction was 7.9–13.2%. There were significant differences in the morphological characteristics of the leaves and roots of diploid and tetraploid plantlets.

High proportion of diploid hybrids produced by interspecific diploid × tetraploid Sorghum hybridization

A perennial version of grain sorghum [S. bicolor (L.) Moench] would create opportunities for greatly reducing tillage and preventing soil degradation. Efforts to select for perenniality and grain production among progeny of hybrids between S. bicolor (2n = 20) and the weedy tetraploid perennial S. halepense (L.) Pers. (2n = 40) are complicated in that F1 hybrids produced by diploid × tetraploid sorghum crosses are usually tetraploid. In 2013, a set of random pollinations between 19 diploid cytoplasmic male-sterile inbred lines and 43 tetraploid perennial plants produced 165 F1 hybrid plants, more than 75% of which had highly atypical plant, panicle, and seed phenotypes. Phenotypic segregation in F2 populations derived from atypical hybrids was also anomalous. Examination of mitotic metaphase cells in F1 or F2 root tips revealed that 129 of the 165 hybrids were diploid. Parentage of the diploid progenies was confirmed using simple-sequence repeat analysis. The mechanism by which diploid hybrids arise from diploid × tetraploid crosses is unknown, but it may involve either production of monohaploid (n = 10) pollen by the tetraploid parent or chromosome elimination during early cell divisions following formation of the triploid zygote. The ability to produce diploid germplasm segregating for S. bicolor and S. halepense alleles could have great utility, both for the development of perennial sorghum and for the improvement of conventional grain sorghum.

In vitro cloning potential and phytochemical evaluations of aneuploid individuals produced from reciprocal crosses between diploid and triploid in Echinacea purpurea L.

Aneuploidy often presents large variations in morphology, physiology, biochemistry, and genetics owing to karyotypic imbalance. This study aimed to evaluate the efficacy of aneuploid breeding in &lt;em&gt;Echinacea purpurea&lt;/em&gt; L, an important medicinal plant. Reciprocal crosses between diploid and triploid plants were performed to generate aneuploid plants. Cross with triploid as female parent resulted in increased production of aneuploid individuals (19 of 23; 82.61%), while using diploid as female parent yielded much higher percentage of diploid progenies (130 of 133; 97.74%). Each aneuploid had particular karyotypic characteristics compared to the parents. The proportions of median, submedian, and subterminal centromere location chromosomes in gross chromosomes among aneuploids and two parents showed large variations. Although aneuploids had relatively lower adventitious bud regeneration rates than their parents, almost half of them looked morphologically normal, with high survival rates when transplanted to ex vitro conditions. Among the bioactive compounds assessed, cichoric acid and chlorogenic acid contents were extremely encouraging. Most aneuploids had higher cichoric acid and chlorogenic acid contents than their parents. For example, A2 had the highest cichoric acid content of 21.98 mg/g dry weight, more than twice the values of diploid and triploid. Meanwhile, A21 had the highest chlorogenic acid content of 1.84 mg/g, approximately five times more than the parental values. Eleven superior aneuploid lines were successfully screened as breeding candidates. The present findings indicated &lt;em&gt;E. purpurea&lt;/em&gt; is highly tolerant of karyotypic imbalance and aneuploid plants could serve as prospective breeding resources in &lt;em&gt;E. purpurea&lt;/em&gt;.

Artificial polyploidy in medicinal plants: Advancement in the last two decades and impending prospects

Medicinal plants are in huge demand since the consumption is widespread and ever-increasing globally. The conventional breeding programs are generally environmental dependent; prone to different biotic and abiotic stresses as well as the secondary metabolite content is too low to harvest. In this context, developing polyploid individuals artificially would be a remarkable approach to increase vigor and attain this objective. Polyploids often exhibit some morphological features that are different or greater in forms than their diploid progenies. Polyploidization can be induced by quite a few antimitotic agents. The most frequently used antimitotic chemicals are colchicine, trifluralin, and oryzalin. The whole method of induced chromosome doubling consists of a series of steps, including an induction phase, regrowth phase, and a confirmation technique to evaluate the rate of achievement. The induction phase depends on different factors, such as explant types, antimitotic agents, its different concentrations, and exposure durations. To evaluate the accomplishment of polyploidization, morphological or anatomical observations are recorded as a rapid method. However, chromosome count and flow cytometry are the most eminent method for absolute confirmation. Despite significant prospects of polyploidization, there has been very little research on medicinal plants. The current review gives an overview of the different parameters of in vitro chromosome doubling, the history of the technique, and progress made over the last two decades.