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In aquaculture, sterile triploids are commonly used for production as sterility gives them potential gains in growth, yields, and quality. However, they cannot be reproduced, and DNA parentage assignment to their diploid or tetraploid parents is required to estimate breeding values for triploid phenotypes. No publicly available software has the ability to assign triploids to their parents. Here, we updated the R package APIS to support triploids induced from diploid parents. First, we created new exclusion and likelihood tables that account for the double allelic contribution of the dam and the recombination that can occur during female meiosis. As the effective recombination rate of each marker with the centromere is usually unknown, we set it at 0.5 and found that this value maximizes the assignment rate even for markers with high or low recombination rates. The number of markers needed for a high true assignment rate did not strongly depend on the proportion of missing parental genotypes. The assignment power was however affected by the quality of the markers (minor allele frequency, call rate). Altogether, 96–192 SNPs were required to have a high parentage assignment rate in a real rainbow trout dataset of 1,232 triploid progenies from 288 parents. The likelihood approach was more efficient than exclusion when the power of the marker set was limiting. When more markers were used, exclusion was more advantageous, with sensitivity reaching unity, very low false discovery rate (<0.01), and excellent specificity (0.96–0.99). Thus, APIS provides an efficient solution to assign triploids to their diploid parents. [ABSTRACT FROM AUTHOR]

This study sought to assess the possibility of genetically improving the performance of the African catfish using triploidy techniques. The experiment was carried out using Completely Randomized Design (CRD) with varied temperatures, time spent before shock after fertilisation, and durations of the shock for the triploid production experiment and four treatments replicated thrice for the culture experiment. Fertilised eggs from each female parent stock were subjected to either cold or heat shock treatments. The result showed a significant (p<0.05) increase in the hatching time and survival of the fertilized eggs subjected to different cold and heat shock treatments as compared to the control which recorded the shortest hatching time of 22.48 ± 0.00 hours. The temperature regime of 2oC recorded the highest approximate yield of triploids (98.33 ± 1.66%), while the prolonged duration of the shock of 30 minutes at the temperature regime of 3oC significantly increased (p<0.05) triploid yield. Comparatively, triploids significantly gained more weight, had an increased growth rate, and grew longer than the diploid counterparts with an average of 11.22 ± 1.07 g, 0.013 ± 0.001%, and 21.49 ± 0.47 cm respectively. The highest comparative cost of the diet of 1000 catfish juveniles occurred in triploids with a stocking density of 7 fishes/m² (N14,132.50). However, the seed, feed, and variable costs consistently decreased with increasing stocking densities across the ploidies. It is therefore concluded that the triploids were superior in both production attributes and cost benefits. [ABSTRACT FROM AUTHOR]

Introduction: The Pacific abalone, Haliotis discus hannai, is one of the most commercially important marine shellfish in China. Cell engineering breeding is an important tool in abalone genetic breeding, and the triploids obtained through this method have high commercial value. However, current research mainly focuses on establishing induction methods and evaluating the growth traits of triploids, while there is a lack of basic research on triploid cytogenetics. Method: In this study, Cytogenetic analysis of triploid Haliotis discus hannai larvae (produced by chemical treatment) and diploid larvae was performed. Result: The results showed that triploid H. discus hannai had a chromosome number of 3n = 54, consisting of 30 metacentric (m) and 24 submetacentric (sm) chromosomes, while the diploids had a chromosome number of 2n = 36, consisting of 20 metacentric (m) and 16 submetacentric (sm) chromosomes. Notably, both triploids and diploids displayed variation in the number of NORs and/or their diameter. The average number of NORs in triploid was significantly higher than that in diploids (p <0.05), but the average diameter of NORs of triploid was no significant different from that of diploid (p> 0.05). Additionally, 5S rDNA localization to 3 submetacentric chromosomes was observed in triploids, compared to 2 submetacentric chromosomes in diploids. The number of 18S rDNA sites displayed positional conservancy and quantitative variability in both diploids and triploids. Specifically, 18S rDNA was found at the end of the chromosome in both groups, with triploids exhibiting a significantly higher number of loci than diploids (p <0.01). Conclusion: This study provides valuable insights into the cytogenetic characteristics of triploid H. discus hannai, which could facilitate further research on the stability of the chromosome set in this species. [ABSTRACT FROM AUTHOR]

Hybridization and polyploidy are currently known as exponential factors for biodiversity. Some Paspalum species can hybridize and originate viable allopolyploids with possible agronomic use. We collected a frost resistance hybrid in north–western Misiones and determined its ploidy level, meiotic behavior, pollen viability, cytoembryology, and seed production in open and self-pollination. To elucidate its origin, we conducted a phenotypic and geographical analysis using herbarium specimens to establish its putative parental species. The hybrid was triploid, exhibiting irregular meiosis with the formation of non-viable pollen and undeveloped embryo sacs, resulting in very low seed production under both pollination conditions. Through morphological analysis, we identified Paspalum urvillei Steud. and the Paniculata group, i.e. Paspalum juergensii Hack., Paspalum umbrosum Trin., and Paspalum paniculatum L., as the putative parental species. Geographic distribution patterns suggested a possible hybridization event between P. urvillei and P. umbrosum, though further investigation is needed to precisely identify which species from the Paniculata group hybridized with P. urvillei. Future studies will help to unravel the complex genetic interactions underlying hybridization in Paspalum species and contribute to our understanding of biodiversity dynamics. [ABSTRACT FROM AUTHOR]

Three groups of mollusks of the triploid Pacific oyster Crassostrea gigas differing in morphometric parameters—fast-growing (FG) with a shell height of over 40 mm; medium-growing (MG), 15 mm < H < 40 mm; and slow-growing (SG), H < 15 mm—have been studied from the Donuzlav estuary (Black Sea). Stable differences have been revealed in the growth rates of juveniles of the same age. Mollusks of the FG group are dominant in weight gain and linear dimensions throughout the study. The average daily increase in the shell height of the studied mollusks ranges from 0.1 to 0.35 mm/day, with maximum values in June and September. The weight increases with different rates: on average, 0.051 g/day in the SG groups, 0.168 g/day in the MG group, and 0.287 g/day in the FG group. The peaks of this parameter have been recorded in August and September, reaching 0.12, 0.26, and 0.43 g/day, respectively. The shell height of slow-growing polyploid oysters has a negative allometry (b = 2.17), while the other two groups are characterized by a clear positive allometry (b = 3.23 for MG and 3.80 for FG); i.e., the increase in weight is faster than the linear growth in juveniles of the species. It has been suggested that polyploidy (triploidy) determines the differences in the growth rates of the same-aged mollusks. The allometry index b can be used to identify growth features at the early stages of oyster development. [ABSTRACT FROM AUTHOR]

Odd ploidy-level cytotypes in sexually reproducing species are considered a dead end due to absent or reduced fertility. If sterility is only partial, however, their contribution to the population gene pool can be augmented by longevity and clonal growth. To test this, we investigated the cytotype origin and spatial pattern, and pollen viability in three relict shrub species of the genus Daphne (Thymelaeaceae Juss.) in central Europe. Daphne cneorum subsp. cneorum is a widespread European species that has a broad ecological amplitude, whereas D. cneorum subsp. arbusculoides and D. arbuscula are narrow endemics of the western Pannonian Plain and the Western Carpathians, respectively. Our study confirmed that all three taxa are diploid. However, of more than a thousand analysed individuals of D. cneorum subsp. cneorum , five in four different populations were triploid. Our data indicate that these triploids most likely originate from recurrent autopolyploidization events caused by the fusion of reduced and unreduced gametes. High pollen viability was observed in all three taxa and in both diploid and triploid cytotypes, ranging from 65 to 100 %. Our study highlights the significant role of odd ploidy-level cytotypes in interploidy gene flow, calling for more research into their reproduction, genetic variability, and overall fitness. Interestingly, while the endemic D. arbuscula differs from D. cneorum based on genetic and genome size data, D. cneorum subsp. arbusculoides was indistinguishable from D. cneorum subsp. cneorum. However, our study reveals that the subspecies differ in the number of flowers per inflorescence. This is the first comprehensive cytogeographic study of this intriguing genus at a regional scale, and in spite of its karyological stability, it contributes to our understanding of genomic evolution in plant species with a wide ecological amplitude. [ABSTRACT FROM AUTHOR]

The Atlantic oyster of Chesapeake Bay has been the focus of intense economic and ecological pressures. In the 1 880s it was the main source for America's favorite food, and the oyster was overharvested to the point of scarcity. Three scientific discoveries concerning the oyster's material properties have been paving its way back from the brink of extinction, First William Keith Brooks studied the embryology of this oyster and showed that its shell served as a necessary part of its life cycle. Second, Roger Newell demonstrated the prodigious water filtration properties of this oyster and linked these properties to its ability to clean the estuary. The discovery of the filtration properties of the oyster was an affordance that enabled the oyster to "partner" with governmental agencies and NGOs who were attempting to restore the bay's clean water, fish, and birdlife, Third, Standish K, Allen, Ximing Guo, and their colleagues formulated a procedure that enabled the manipulation of oyster development to yield tasty, fast-growing, and disease-resistant triploid oysters. The disease-resistant oysters together with knowledge of the oyster's life cycle enabled the proliferation of the oyster by conservation groups. The goal of Chesapeake Bay conservation changed from "Save the oyster" to "Plant more oysters; help save the bay." This paper is part of a special issue entitled "Making Animal Materials in Time," edited by Laurence Douny and Lisa Onaga. [ABSTRACT FROM AUTHOR]

The paper presents the results of the microsatellite genotyping of hybrid lizards D.armeniaca × D. valentini from sympatric populations of Armenia. Triploid individuals are identified based on the totality of the Du281 and Du47G loci and their origin is determined. It is shown that the hybrids contain both alleles of the maternal parthenospecies D. armeniaca and alleles of the paternal species D. valentini. [ABSTRACT FROM AUTHOR]

Obtaining citrus polyploids, especially from triploid individuals, is of great importance for genetic improvement programs, as they produce seedless fruits. Therefore, the aim of this study was to use flow cytometry analyses to identify polyploid individuals among tangerine-type seedlings originating from seeds germinated in vitro. Fruits were collected from 13 different genotypes in the municipality of Mucugê (state of Bahia, Brazil). The seeds were then removed and classified as developed (seeds with well-formed integument), underdeveloped (seeds with wrinkled integument) and small (seeds of 1/3 to 1/6 of normal size). After the integument was removed, the seeds were disinfected and introduced into a WPM culture medium, in which they remained for 120 days. After this period, the percentage of germinated seeds and growth variables were evaluated, and ploidy analysis was conducted using flow cytometry. The developed seeds displayed a higher germination rate (91.5%) than the others. The small and underdeveloped seeds resulted in a considerable frequency of spontaneous polyploids (11%), and one haploid plant was also obtained from the latter class. Key message: The ploidy of 13 citrus genotypes was investigated using flow cytometry. In addition to polyploid plants that are of interest to breeding programs, there was the identification of a haploid plant. [ABSTRACT FROM AUTHOR]

The aim of the paper was the study of embryos survival rate after eggs triploidy treatment in rainbow trout (Oncorhynchus mykiss Walbaum). The triploidy induction was preformed during the cold period of January when the water temperature reached 8-10°C and the environmental conditions inducted the natural reproduction of rainbow trout. The reproducers used for the experiments were between 3-5 years old. The spawn fertilization was made by the wet method. For each experimental lot higher losses have been observed at the end of the first, second, third and the middle of the fourth decade. The T1 experimental lot has registered the highest losses in the first decade while the T2 lot in the last decade. The losses registered for the T1 and T2 experimental lots during the spawn incubation were significant higher comparing to the control lot M as resulted by the statistical interpretation of data’s.

One of the most promising trends in apple breeding is polyploidy. Triploid cultivars show higher fruiting stability and increased self-fertility. The easiest way to obtain triploids is to cross diploid and tetraploid cultivars among themselves. The main limiting factor in this case is a restricted number of initial tetraploid forms whose characteristics affect the quality and prospects of the resulting hybrid progeny.The staff of Sverdlovsk Horticultural Breeding Station in the Middle Urals produced and analyzed 5 hybrid families using cv. ‘Papirovka tetraploidnaya’ as the paternal source; the latter’s pollen was supplied by Acad. E. N. Sedov from the All-Russian Research Institute of Fruit Crop Breeding. Ninety hybrid seedlings were studied.The study showed that ‘Papirovka tetraploidnaya’ with a high degree of probability conveyed the following traits to its progeny: large fruit size, fruit ripening in early summer, midsummer and autumn, loose or medium density of coarse fruit flesh, and nonoutstanding fruit taste (scoring 3.8–4.2 points).

Pummelos and hybrids, such as grapefruits, have high furanocoumarin and low flavonoid contents. Furanocoumarins interact negatively with certain drugs, while flavonoids are antioxidant compounds with health benefits. To obtain new grapefruit-like varieties with low furanocoumarin and high flavonoid contents, diploid and triploid hybrid populations from crosses between diploid and tetraploid "Clemenules" clementine and diploid "Pink" pummelo were recovered and analyzed. With regard to furanocoumarins, triploids produce less bergapten, bergamottin and 6,7-DHB than diploids. Regarding flavonoids, triploids yielded more eriocitrin, narirutin, hesperidin and neohesperidin than diploids, whereas no differences were observed in neoeriocitrin and naringin. These results indicate that, the strategy to recover triploid hybrids by 4x × 2x crosses is more appropriate than the recovery of diploid hybrids by 2x × 2x crosses for obtaining grapefruit-like varieties of citrus with lower furanocoumarin and higher flavonoid contents. [ABSTRACT FROM AUTHOR]

In the present research we produced triploid, mitogynogenetic (doubled haploid; DH) and meiogynogenetic brook trout (Salvelinus fontinalis) to examine efficiency of these technologies and potential susceptibility of chromosome set manipulated individuals for the spinal disorders. Triploidy was induced by shocking (High Hydrostatic Pressure – HHP) of fertilized eggs 30 min. after insemination. In turn, gynogenetic development was induced by activation of eggs with UV-irradiated sperm. Activated eggs were then exposed to HHP shock applied 30 and 420 minutes after insemination to provide meiogynogenotes and gynogenetic DHs, respectively. When compared to non-manipulated diploids, the highest survival rates were observed among triploid brook trout while DHs showed the highest mortality. Malformation rates in the diploid larvae from the control groups did not exceed 7.0% while percentage of malformed triploid individuals equaled 19.1%. Drastically increased number of deformed larvae (> 30%) was observed in both DH and meiogynogenetic individuals. Intensification of kyphosis and scoliosis was clearly demonstrated in the gynogenetic and triploid brook trout. Genetic factors such as increased number of sets of chromosomes in triploids and expression of lethal alleles in the gynogenetic fish plus side effects of HHP shock utilized for retention of the second polar body or inhibition of the first cell cleavage when induced triploid and gynogenetic development have been discussed to affect survival rates and prevalence for the skeletal deformities in the chromosome set manipulated brook trout. [ABSTRACT FROM AUTHOR]

Triploid organisms, in particular oysters, are widely used in marine aquaculture. However, the advantage of triploid oysters compared to diploids has not been proven in all cases. Comparative morphological analysis of Pacific oysters Crassostrea gigas of different ploidy levels allows evaluating the benefits of raising triploids in the Black Sea. First, the morphological characteristics of diploid and triploid Pacific oysters C. gigas farmed in the Black Sea were studied. Allometric ratios of weight (W, g) and shell height (H, mm) of oysters were obtained, which are described by the equations W2n = 4 x 10-4 x H2n 2.56, R² = 0.86 and W3n = 9 x 10-5 x H3n 2.90, R² = 0.91. Triploids showed positive allometry and had more biomass at smaller shell height than diploid oysters. A clear linear relationship of the height and length of oyster shells was established. Significant differences in linear parameters between 2n and 3n C. gigas farmed in Donuzlav Liman are not seen. Based on these results, it is assumed that the advantage of the growth of 3n mollusks is less evident in farms located at high latitudes. The environmental factors and farm technology have probably affected the growth of oysters to a greater degree than their ploidy. [ABSTRACT FROM AUTHOR]

The ploidy level can be useful in evaluating reproductive and somatic compatibility, an important parameter in scion and rootstock breeding programs. Evaluation of nuclear DNA content was performed in order to determine ploidy level of 31 rootstocks of genus Prunus for plum, sour cherry and sweet cherry. In the first stage of the research, the conditions of flow cytometry analysis with application of propidium iodide for DNA staining were optimized. Repeatable results and relatively good-quality histograms were obtained using Partec extraction buffer with 1% PVP (polyvinylpyrrolidone) addition, with incubation time from 50 to 90 min. The best internal standard for flow cytometry analysis proved to be tomato (Solanum lycopersicum L.) 2C = 1.96 pg for rootstocks with a nuclear DNA content from 0.55 to 1.64 pg, and soybean (Glycine max (L.) Merr.) 2.50 pg for rootstocks with a larger nuclear DNA contents from 1.8 to 2.3 pg. In five plum rootstocks, 2C values ranged from 0.61 to 0.67 pg indicating their diploid chromosome number. One rootstock was identified as tetraploid (2C = 1.34 pg), and four rootstocks as hexaploids owing to their DNA contents from 2.07 to 2.23 pg. One rootstock was considered a pentaploid due to its 2C value of 1.64 pg which was approximately two and a half times more than in diploid Prunus sp. In nine cherry rootstocks, 2C DNA values ranged from 0.74 to 0.86 pg indicating their diploid chromosome number. Nine cherry rootstocks were identified as triploids with their 2C DNA contents from 1.03 to 1.24 pg. Two cherry rootstocks were considered as tetraploids having 2C DNA of 1.39 pg. The ploidy level of cherry and plum rootstocks was evaluated in relation to morphological and agronomic traits. The tendency to increase the size of stomata and leaves along with an increase in the ploidy level was observed within Prunus rootstock genotypes; however, the correlations between these traits were not so evident. Therefore, stomata and leaf size cannot be considered as a morphological marker indicating ploidy level. The evaluated nuclear DNA contents / ploidy levels as well as stomata and leaf size are the additional descriptors of Prunus rootstocks that can be useful for identifying genotypes. [ABSTRACT FROM AUTHOR]

The Pacific oyster occurs on all continents but Antarctica (Mann 1979) and for the past several years has had the highest annual production of any freshwater or marine organism (4.2 million metric tons in 2002, worth $3.5 billion; FAO 2004). About 92 million pounds of Pacific oyster meat were produced on the West Coast in 2000, with a farm-gate value of nearly $70 million (Toba and Chew 1999). West Coast production exceeds the harvest of Eastern oysters on either the Gulf or Atlantic Coasts, primarily because diseases have wiped out those natural stocks. As the Pacific oyster does not naturally reproduce along much of the West Coast, seed was imported from Japan for decades (Chew 1984). In the early 1980s, however, the industry adopted hatchery techniques and now relies mainly on hatchery seed. This sets the stage not only for commercial breeding programs, which industry identifies as a top priority (Pacific Shellfish Institute 1999), but also for development in the future of a mature seed industry servicing global markets.

Wild Helianthus species are a valuable genetic resource for the improvement of cultivated sunflower. We report the discovery and characterization of a unique high frequency production of triploids when cultivated sunflower was pollinated by specific accessions of diploid Helianthus nuttallii T. & G. and H. maximiliani Schr. Genomic in situ hybridization (GISH) analyses indicated that the triploid F1s had two genomes from the wild pollen sources and one from the cultivated line. Mitotic chromosome analyses indicated that the frequency of triploid progenies from the crosses of cultivated lines × H. nuttallii accession 102 (N102) was significantly higher than those of unexpected polyploid progenies from the crosses of wild perennial species × N102, and no unexpected polyploids were obtained from the reverse crosses. Pollen stainability analysis suggested the existence of a low percentage of unreduced (2n) male gametes in some accessions, especially N102 and H. maximiliani accession 1113 (M1113), which were generated at the telophase II and tetrad stages of meiosis. The triploid F1s could be the results of preferred fertilization of the low frequency of 2n male gametes with the female gametes of the cultivated sunflower, due to the dosage factors related to recognition and rejection of foreign pollen during fertilization. The triploids have been used to produce amphiploids and aneuploids. Future studies of the male gametes’ fate from pollination through fertilization will further uncover the mechanism of this whole genome transmission. Studies of the genetic control of this trait will facilitate research on sunflower polyploidy speciation and evolution, and the utilization of this trait in sunflower breeding.

Abstract Background The Atlantic salmon aquaculture industry is investigating the feasibility of using sterile triploids to mitigate genetic interactions with wild conspecifics, however, studies investigating diploid and triploid performance often show contrasting results. Studies have identified dosage and dosage-compensation effects for gene expression between triploid and diploid salmonids, but no study has investigated how ploidy and parent-origin effects interact on a polygenic trait in divergent lines of Atlantic salmon (i.e. slow growing wild versus fast growing domesticated phenotype). This study utilised two experiments relating to the freshwater growth of diploid and triploid groups of pure wild (0% domesticated genome), pure domesticated (100% domesticated genome), and F1 reciprocal hybrid (33%, 50% or 66% domesticated genome) salmon where triploidy was either artificially induced (experiment 1) or naturally developed/spontaneous (experiment 2). Results In both experiments, reciprocal hybrid growth was influenced by the dosage effect of the second maternal chromosome, with growth increasing as ploidy level increased in individuals with a domesticated dam (from 50% to 66% domesticated genome), and the inverse in individuals with a wild dam (from 50% to 33% domesticated genome). Conclusions We demonstrate that the combined effect of ploidy and parent-origin on growth, a polygenic trait, is regulated in an additive pattern. Therefore, in order to maximise growth potential, the aquaculture industry should consider placing more emphasis on the breeding value of the dam than the sire when producing triploid families for commercial production.

In this chapter, we report advances in tissue culture applied to Passiflora. We present reproducible protocols for somatic embryogenesis, endosperm-derived triploid production, and genetic transformation for such species knowledge generated by our research team and collaborators in the last 20 years. Our research group has pioneered the work on passion fruit somatic embryogenesis, and we directed efforts to characterize several aspects of this morphogenic pathway. Furthermore, we expanded the possibilities of understanding the molecular mechanism related to developmental phase transitions of Passiflora edulis Sims. and P. cincinnata Mast., and a transformation protocol is presented for the overexpression of microRNA156., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Abstract Due to massive mortality of Crassostrea gigas spat in France since 2008, a "plan de sauvegarde" was set up from 2011 to 2014 (hereafter referred to as PS1 to PS4), in order to reduce the shortage of spat. This plan involved the participation of commercial hatcheries, the French Research Institute for Exploitation of the Sea (Ifremer), and the Direction des Pêches Maritimes et de l'Aquaculture (DPMA) of the French Ministry of Agriculture. It was based on selecting diploid lines of C. gigas for their higher resistance to the oyster herpesvirus OsHV-1 (2nR group), and one of these lines was subsequently tetraploidized (4nR group). Both the 2nR and 4nR groups were produced by Ifremer, and then transferred to commercial hatcheries that produced the selected triploids (3nR groups). We report here the mortality rates of the 3nR group for each of the four "plan de sauvegarde" campaigns and compare these with the mortalities of the classic production of commercial hatcheries (both 2n and 3n), benchmarks of selected (2nR group) and unselected (2n-control group) oysters produced by Ifremer, and wild-caught spat, representing a total of 104 diploid and triploids batches. For PS1, the 3nR group had a mean mortality of 67% and did not show any advantage over the 2n- and 3n-commercial groups, suggesting a lack of genetic progress in the 2nR and 4nR groups. For PS2, OsHV-1 resistance was increased in both the 2nR and 4nR groups and, consequently, the 3nR group exhibited a mean mortality of 52%, which was significantly lower than the mortality of the 2n- (87%) and 3n-(76%) commercial groups in 2012. Unfortunately, the mortality of the 3nR group reached 62% and 71% in PS3 and PS4, respectively, although it was expected to be lower than that in PS2. OsHV-1 DNA was quantified in the live oysters at deployment (1356 oysters) and at the endpoint (1171 oysters), as well as in moribund oysters sampled during peak mortality (539 oysters). The results strongly supported the involvement of this pathogen during the main mortality outbreak in May/June. Meanwhile, Vibrio aestuarianus was also suspected to cause unexpected mortality of PS3 oysters in August and September, and it was detected in moribund PS4 oysters during both the mortality events, in May and July. Despite genetic improvement for OsHV-1 resistance, this translated into variable commercial genetic gain. This could be explained by the limited genetic backgrounds of the 2nR and 4nR groups, the reemergence of V. aestuarianus in France since 2012, the changing levels of genetic improvement in both the 3nR group and the commercial groups, as well as the limited broodstock genetic variation where small numbers of males were used. Results on growth and yield are discussed. Highlights • Four "plan de sauvegarde" campains (PS) were set up to reduce the spat shortage in France from 2011 to 2014. • Selection criterion was only based on the resistance to the infection by OsHV-1. • The mortality of 5 groups were compared for each PS representing a total of 104 diploid and triploids batches. • The 3nR group only had a significant decrease of mortality over the 2n and 3n commercial groups in 2012. • The failure of the "plan de sauvegarde" in 2013 and in 2014 could be explained by the role of V. aestuarianus. [ABSTRACT FROM AUTHOR]

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The paper presents new data on 28-30-year-olds testing of triploid poplar hybrids (2n = 3x = 57), obtained using in hybridization artificially obtained unreduced diploid (2n) pollen (induced by high temperature or colchicines treatment) in Voronezh region. The growth dynamics, preservation and timber productivity of 26 triploid and diploid (2n = 2x = 38) clones of Populus alba L., P. balsamifera L., P. nigra L. and intersectional hybrids (Populus deltoides Marsh. × P. balsamifera L.) were studied. It was revealed that a preservation of triploid hybrids of white poplar at 28-year-old age was higher than diploid hybrids. The greatest loss of plants of white poplar was observed during the first three years after planting of cutting seedlings in the nursery. In comparison, major loss of plants of P. balsamifera L., P. nigra L. and intersectional hybrids (P. deltoides Marsh. × P. balsamifera L.) was observed after the 2010 drought. Especially high plant mortality was observed in P. balsamifera clone (preservation of 40 %) and to a lesser extent in poplar «Robusta-236» (preservation of 60 %). There were no statistically significant differences in growth between groups of diploid and triploid white poplar clones. Only part of the artificially produced autotriploid hybrids (40 %) were characterized by fast growth and productivity. It is suggested that the heterosis effect in triploids associated with participation of high heterozygous 2n gametes in hybridization. Such were formed on the basis of a synapsis of chromosomes and loss of the I-st meiotic division. Six best triploid and diploid poplar hybrids have been selected as promising for Voronezh region.

Pelophylax esculentus is an interspecific hybrid which reproduces hemiclonally by crossing with the parental species (P. ridibundus or P. lessonae). The structure of hemiclonal population systems is of great interest. The majority of investigations into populations of water frogs deal with samples of mature animals, while subadults are less studied. We collected a random sample of 73 small water frogs from three localities in the Siverskyi Donets River floodplain. All frogs were measured, injected with colchicines and killed after anesthesia. We determined the species specifity, sex, age and ploidy of every individual. In addition, we measured testis length and studied the germ cells of all males by means of karyological analysis. We calculated the portion of triploids in the largest subsample from the vicinity of the Biological Station of V.N. Karazin Kharkiv National University and carried out a meta-analysis of previous publications dealing with composition of green frog samples from this locality. The proportion of triploids in our sample appeared to be approximately the same as 12 years ago. However, this proportion in our sample differed significantly from that obtained in recent samples of green frogs belonging to other age groups (adults and metamorphs) from the same locality. The share of triploids of P. esculentus is the lowest in the sample of metamorphs. This proportion increases in froglets because of early death of representatives of parental species which originated from hybrid-hybrid crossing. Then the number of triploids among adult P. esculentus individuals declines again probably because of their lower viability compared to diploids. We have revealed that subadult diploids have erythrocytes smaller than 28 microns, while triploids’ erythrocytes exceed 27 microns. Therefore, in borderline cases true ploidy could be determined only by the karyological technique. The average ratio between testis length and body length appeared to be larger in the parental species than in both diploid and triploid hybrids. Karyological analysis has revealed that P. esculentus had significantly lower portions of spermatocytes I with normal karyotype (13 bivalents) in the testis in comparison with P. ridibundus, but this value increases in adult hybrids. We suggest that increasing of spermatogenesis stability in adult frogs as opposed to subadults might be the consequence of both selection of germ cell lines in the testis and more frequent survival of individuals with stable gametogenesis.

Olea europaea L. subsp. laperrinei (Oleaceae) is an endemic taxon of the mountainous regions of central Sahara, consisting of currently fragmented and small relict populations. The tree can propagate vegetatively or by seed, but no recent natural regeneration was observed in the Algerian massive populations, some of which are considered threatened with extinction. Sterile triploid individuals were also identified in some populations showing increasing vigour. As a result of its long persistence and despite its rarity, the Laperrine's olive is an iconic component of Saharan mountain ecosystems. The aim of this study is to develop an efficient micropropagation protocol for both diploid and triploid Laperrine's olive to safeguard and preserve this genetic resource. Best shoot propagation was obtained on a modified Murashige and Skoog medium supplemented with 9.2 μM zeatin. Best rooting rate of regenerated shoots was achieved on the same culture medium supplemented with 4.8 μM indole-3-butyric acid. In absence of morphological changes of in vitro regenerated plants acclimatized to the greenhouse, genetic conformity was assessed by simple sequence repeat screening. Our results suggest that in vitro propagation could be a useful tool for conservation of both diploid and triploid threatened Laperrine's olive. [ABSTRACT FROM AUTHOR]

Triploids can play an important role in polyploid evolution. However, their frequent sterility is an obstacle for the origin and establishment of neotetraploids. Here we analyzed the microsporogenesis of triploids (x = 7) and the crossability among cytotypes of Turnera sidoides, aiming to test the impact of triploids on the origin and demographic establishment of tetraploids in natural populations. Triploids of T. sidoides exhibit irregular meiotic behavior. The high frequency of monovalents and of trivalents with non-convergent orientations results in unbalanced and/or non-viable male gametes. In spite of abnormalities in chromosome pairing and unbalanced chromosome segregation, triploids are not completely sterile and yielded up to 67% of viable pollen. Triploids that originated by the fusion of 2 n × n gametes of the same taxon showed more regular meiotic behavior and higher fertility than triploids from the contact zone of diploids and tetraploids or triploids of hybrid origin. The reproductive isolation of T. sidoides cytotypes of different ploidy level is not strict and the 'triploid block' may be overcome occasionally. Triploids of T. sidoides produce diploid and triploid progeny suggesting that new generations of polyploids could originate from crosses between triploids or from backcrosses with diploids. The capability of T. sidoides to multiply asexually by rhizomes, would enhance the likelihood that a low frequency of neopolyploids can be originated and maintained in natural populations of T. sidoides. [ABSTRACT FROM AUTHOR]

Xenogenesis is an innovative technology for hybrid catfish (♀ channel catfish, Ictalurus punctatus , × ♂ blue catfish, I. furcatus) embryo production. The xenogeneic process can be accomplished by transplanting undifferentiated diploid germline stem cells derived from donor fish into sterile recipients. This methodology enables recipients to produce donor-derived gametes. Until recently, the timing of transplantation of donor cells into hosts was done with limited knowledge of the best age to inject cells. The age of the host could critically affect the success of germ cell transplantation. The present study aimed to identify the best age of the triploid channel catfish to transplant blue catfish stem cells for production of xenogeneic catfish. Triploid channel catfish fry were injected with blue catfish stem cells labeled with PKH26 dye from 0 to 18 days post-hatch (DPH). Then at 50 DPH (1st time interval) and 90 DPH (2nd time interval), total length (TL), weight (BW), and survival of recipients were evaluated. Colonization of donor cells was evaluated in recipients using PKH26 dye fluorescence to calculate percent cell (<150 μm2) and cluster areas (>150 μm2). PCR determined the percentage of xenogens from gonads. Day of stem cell injection had no impact on TL and BW of recipient fish when evaluated at both sampling intervals. Survival of recipients injected with blue catfish stem cells increased from 0 to 5.4 DPH. After 5.4 DPH, survival remained high (≥82%) for fry injected until 18 DPH. At the 1st time interval, cell and cluster area increased as recipients fish injected from 0 to 5.4 DPH and 0 to 5.6 DPH, respectively. Thereafter, fluorescent cell and cluster area in the host declined with no further decrease after 11.3 and 10.4 DPH, respectively. At the 2nd time interval, cell and cluster area increased as recipients were injected from 0 to 5.8 DPH and 0 to 5.7 DPH and significantly declined with no further decrease after 10.2 and 11.3 DPH, respectively. At the 1st time interval, the highest percentage of xenogens were detected when recipients were injected from 3 to 5 DPH (83.3%), while at the 2nd time interval, the highest percentage of xenogens was detected from 4 to 6 DPH (83.3%). Our results show that 4 to 6 DPH is a suitable timespan to inject donor-derived stem cells into recipients. These findings will enhance the efficiency of germ cell transplantation for commercial-scale hybrid catfish production. • Evaluate colonization capability of transplanted blue catfish stem cells • At 50 DPH, significantly highest cell and cluster area detected at 5.4 DPH & 5.6 DPH. • At 90 DPH, significantly highest cell and cluster area detected at 5.8 DPH & 5.7 DPH. • 83.3% xenogens resulted from gonadal PCR analysis when recipients injected 3–6 DPH. • 4 to 6 DPH is a suitable timespan to inject donor-derived stem cells into recipients. [ABSTRACT FROM AUTHOR]

Fertility of backcross triploid hybrids containing one genome of Prussian carp and two genomes of common carp is investigated. The females of hybrids of Prussian carp and common carp (Prussian × common carp) are prolific and produce diploid gametes. Since males of such hybrids are sterile, their reproduction is realized by means of induced gynogenesis. Triploid progeny is obtained by backcrossing female Prussian × common carp with carp males. Among triploids obtained from hybrids F and among hybrids of the first gynogenetic generation, there were no prolific specimens. However, in reproduction of diploid hybrids by means of gynogenesis during six generations, the female fertility in the backcross progeny is restored. From backcross triploid females (daughters of Prussian × common carp of the sixth gynogenetic generation), a viable triploid gynogenetic progeny and a tetraploid backcross (by carp) progeny are obtained. The obtained data may be considered as the experimental proof of the hypothesis of reticular speciation. [ABSTRACT FROM AUTHOR]

Background: The Atlantic salmon aquaculture industry is investigating the feasibility of using sterile triploids to mitigate genetic interactions with wild conspecifics, however, studies investigating diploid and triploid performance often show contrasting results. Studies have identified dosage and dosage-compensation effects for gene expression between triploid and diploid salmonids, but no study has investigated how ploidy and parent-origin effects interact on a polygenic trait in divergent lines of Atlantic salmon (i.e. slow growing wild versus fast growing domesticated phenotype). This study utilised two experiments relating to the freshwater growth of diploid and triploid groups of pure wild (0% domesticated genome), pure domesticated (100% domesticated genome), and F1 reciprocal hybrid (33%, 50% or 66% domesticated genome) salmon where triploidy was either artificially induced (experiment 1) or naturally developed/spontaneous (experiment 2). Results: In both experiments, reciprocal hybrid growth was influenced by the dosage effect of the second maternal chromosome, with growth increasing as ploidy level increased in individuals with a domesticated dam (from 50% to 66% domesticated genome), and the inverse in individuals with a wild dam (from 50% to 33% domesticated genome). Conclusions: We demonstrate that the combined effect of ploidy and parent-origin on growth, a polygenic trait, is regulated in an additive pattern. Therefore, in order to maximise growth potential, the aquaculture industry should consider placing more emphasis on the breeding value of the dam than the sire when producing triploid families for commercial production. [ABSTRACT FROM AUTHOR]

In multicellular organisms, cell size may have crucial consequences for basic parameters, such as body size and wholebody metabolic rate (MR). The hypothesis predicts that animals composed of smaller cells (a higher membrane surface-to-cell volume ratio) should have a higher mass-specific MR because a large part of their energy is used to maintain cell membranes and ionic gradients. In this article, we investigated the link between cell size and MR in diploid and triploid tadpoles and froglets of the hybridogenetic frog Pelophylax esculentus. In our previous study, we showed that triploids had significantly larger cells (erythrocytes, hepatocytes, and epidermal cells were measured). Therefore, we hypothesized that triploid tadpoles and froglets would have a lower standard metabolic rate (SMR). Our study demonstrated for the first time two distinct effects of polyploidy/ cell size onMRwithin a single species developing in both aquatic and terrestrial habitats. As we hypothesized, diploid tadpoles had a higher SMR than triploids, whereas in froglets, ploidy did not affect the SMR. We also found that the water temperatures in which tadpoleswere reared had no effect on the SMR of froglets after metamorphosis. Based on our results and other reports, we suggest that cell size may have more consequences for whole-body MR in aquatic habitats than in terrestrial habitats because oxygen is less available in water and its availability in relation to oxygen demand decreases with temperature. [ABSTRACT FROM AUTHOR]

Heliconia L., the only genus in the Heliconiaceae family, comprises about 380 species with high ornamental potential. However, the identification of genotypes-mainly based on morphological characteristics-has generated synonyms. Therefore, it becomes necessary to apply novel techniques to differentiate genotypes and elucidate the origin of hybrids and triploids. The aim of the present work was the cytogenetic characterization of 18 Heliconia genotypes, including three hybrids, two triploids and their possible parent plants, by means of chromosome counting, staining with the fluorochromes CMA and DAPI, and FISH for 45S and 5S rDNA sites. The analyses revealed 16 diploid (2 n = 2 x = 24) and two triploid genotypes (2 n = 3 x = 36), with new counts for eight genotypes, including the triploid 'Suriname Sassy'. The karyotypes were symmetric, with chromosomes varying from 0.88 to 3.35 µm. Regarding the CMA/DAPI staining and FISH, one CMA/DAPI/5S rDNA band was observed in the proximal region of two and three small chromosomes in the diploid and triploid genotypes, respectively. The CMA/DAPI/45S rDNA markings varied from two to four sites per genotype, revealing some interesting heteromorphisms. The distribution of 5S and 45S rDNA sites, both CMA-positive, corroborated the origin of the triploid genotypes 'Sassy' and 'Suriname Sassy' from diploid genotypes of H. psittacorum, as well as the origin of the hybrids of H. psittacorum × H. spathocircinata ('Golden Torch' and 'Golden Torch Adrian') and H. caribaea × H. bihai cv. 'Jacquinii' from their respective parent species. [ABSTRACT FROM AUTHOR]

Eight triploids were screened among offspring of the rubber tree clone GT1 x different clones by flow cytometry and chromosome counting. Twenty-five simple sequence repeat (SSR) markers were screened to identify the origin of 2n gametes, to determine the male parents of these triploids, and to evaluate the mechanism of 2n gamete formation using band configurations and microsatellite DNA allele counting peak ratios (MAC-PR). The results showed that 2n gametes originated from the maternal rubber tree clone GT1, contributing the extra genome copy present in the triploids. It was confirmed that GT1 is able to produce a 2n megagametophyte spontaneously. Many male parents were shown to provide pollen for formation of triploid rubber trees, including clones RRIC 103, Yunyan 277-5, and three other clones. The second division restitution (SDR) was likely the main mechanism involved in formation of megagametophytes in GT1, as the rate of maternal heterozygosity restitution (HR) of all eight triploids varied from 27.78% to 75.00%, with a mean of 51.46%, and all 25 markers varied from 0% to 100%, with a mean of 51.69%. Elucidation of the origin and formation of 2n gametes will help optimize further sexual hybridization of polyploid rubber trees. [ABSTRACT FROM AUTHOR]

O objetivo deste trabalho foi avaliar características agronômicas de genótipos de bananeira, em três ciclos de produção. O experimento foi realizado em blocos ao acaso, com parcelas subdivididas e cinco repetições, em Rio Branco, AC. Os genótipos Preciosa, Japira, Pacovan Ken, Pacovan, PA42-44, Prata-anã, ST12-31, FHIA 02, Nanicão, Grande Naine, Calipso, Ambrósia e Bucaneiro foram avaliados quanto aos caracteres: altura da planta; diâmetro do pseudocaule; número de folhas vivas na floração e na colheita; ciclo de formação do cacho da floração à colheita; número de pencas por cacho; massa do fruto e do cacho; e produtividade. As cultivares Preciosa e Pacovan Ken apresentaram as maiores alturas, e os híbridos PA42-44 e FHIA 02, e as cultivares Prata-anã, Nanicão e Grande Naine, o porte mais baixo. As cultivares Nanicão, Ambrósia, Bucaneiro, Pacovan, Prata-anã e Grande Naine e o híbrido ST12-31 apresentaram os menores números de folhas vivas na colheita. A cultivar Preciosa e o híbrido FHIA 02 foram os mais produtivos. Os híbridos PA42-44 e FHIA 02 apresentam características agronômicas promissoras e podem ser incorporados ao sistema produtivo, assim como os híbridos de Pacovan, já adaptados e recomendados para o cultivo no Estado do Acre.This work aimed to evaluate agronomic traits of banana genotypes, in three production cycles. The experimental design was a complete randomized block in split plot arrangement, with five replicates, in Rio Branco, AC, Brazil. The genotypes Preciosa, Japira, Pacovan Ken, Pacovan, PA42-44, Prata-anã, ST12-31, FHIA 02, Nanicão, Grande Naine, Calipso, Ambrosia, and Bucaneiro were evaluated regarding the characters: plant height; pseudostem diameter; number of green leaves at flowering and at harvesting; bunch development period from flowering to harvesting; number of hands per bunch; mean fruit weight; bunch weight; and yield. The cultivars Preciosa and Pacovan Ken were the tallest ones; and the hybrids PA42-44 and FHIA 02, and the cultivars Prata-anã, Nanicão and Grande Naine were the shortest ones. The cultivars Nanicão, Ambrosia, Bucaneiro, Pacovan, Prata-anã and Grande Naine and the hybrid ST12-31 had the smallest numbers of green leaves at harvesting. The cultivar Preciosa and the hybrid FHIA 02 were the most productive. The hybrids PA42-44 and FHIA 02 show promising agronomic traits and can be incorporated to the productive system, as well as the Pacovan hybrids, already adapted and recommended for cultivation in Acre State.

A diagnose foliar é bastante útil na determinação do estado nutricional das plantas. As exigências nutricionais da bananeira podem diferir em função das suas características genéticas. O trabalho objetivou determinar os teores de macro e micronutrientes na terceira folha de genótipos de bananeira. Foram selecionados 24 genótipos de bananeira (triplóides e tetraplóides), em dois ciclos de produção (1999 e 2000), do Banco Ativo de Germoplasma de Banana da Embrapa Mandioca e Fruticultura Tropical, determinando-se os teores foliares de macronutrientes (N, P, K, Ca, Mg e S) e de micronutrientes (B, Cl, Cu, Fe, Mn e Zn). Os resultados indicaram que existe variação nos teores foliares entre plantas do mesmo grupo genômico e entre os ciclos de produção, com teores médios mais elevados no segundo ciclo para N, P, Ca, Mg, S, Cu e Mn e mais baixos para K, Cl, B, Fe e Zn. O N variou de 21,6 a 28,5 g kg-1, o K de 13,7 a 30,8 g kg-1 e foram os macronutrientes com teores mais elevados nas folhas. O teor de Cl variou de 10,4 a 24,7 g kg-1, o Mn de 43 a 574 mg kg-1 e o Fe de 56 a 212 mg kg-1, sendo os micronutrientes com teores mais elevados nas folhas.The leaf diagnosis is quite useful for the determination of the nutritional state of plants. The nutritional banana tree demands can differ in accordance with genetic characteristics. The aim of present work was to determinate the macro and micronutrients contents in the third leaf of banana genotypes. Twenty four banana genotypes were selected (triploids and tetraploids), in two production cycles (1999 and 2000), in the Active Germoplasm Bank of Banana at Embrapa Mandioca e Fruticultura Tropical, in Cruz das Almas, Bahia, Brazil. The leaf contents of macronutrients (N, P, K, Ca, Mg and S) and micronutrients (B, Cl, Cu, Fe, Mn and Zn) were determined. The results showed that occurred variation in leaf contents among plants in the same genome group and between the first and second production cycles, with higher medium levels in the second cycle for N, P, Ca, Mg, S, Cu and Mn and lower ones for K, Cl, B, Fe and Zn. The nitrogen contents 21.6 to 28.5 g kg-1 and K 13.7 to 30.8 g kg-1 and they were the macronutrients with the highest contents in the leaves. The chlorine contents was 10.4 to 24.7 g kg-1, manganese 43 to 574 mg kg-1 and iron 56 to 212 mg kg-1,and they were the micronutrients with the highest contents in leaves.

Previous studies reported that low temperatures result in increases in both cell size and body size in ectotherms that may explain patterns of geographic variation of their body size across latitudinal ranges. Also, polyploidy showed the same effect on body size in invertebrates. In vertebrates, despite their having larger cells, no clear effect of polyploidy on body size has been found. This article presents the relationship between temperature, cell size, growth rate, and body size in diploid and polyploid hybridogenetic frog Pelophylax esculentus reared as tadpoles at 19° and 24°C. The size of cells was larger in both diploid and triploid tadpoles at 19°C, and triploids had larger cells at both temperatures. In diploid and triploid froglets, the temperature in which they developed as tadpoles did not affect the size of their cells, but triploids still had larger cells. Triploid tadpoles grew faster than diploids at 19°C and had larger body mass; there was no clear difference between ploidies in growth rate at 24°C. This indicates better adaptation of triploid tadpoles to cold environment. This is the first report on the increase of body mass of a polyploid vertebrate caused by low temperature, and we showed relationship between increase in cell size and increased body mass. The large body mass of triploids may provide a selective advantage, especially in colder environments, and this may explain the prevalence of triploids in the northern parts of the geographic range of P. esculentus. [ABSTRACT FROM AUTHOR]

O conhecimento das características pós-colheita de novos híbridos de bananeira é uma importante informação que auxilia o melhorista em sua tomada de decisão. Este trabalho teve como objetivo avaliar genótipos de bananeira com relação às características de pós-colheita e resistência ao desprendimento do fruto. Foram utilizados frutos da segunda penca de 16 híbridos (Calipso, Bucaneiro, Ambrosia, YB42-21, PV42-53, PV42-68, PV42-81, PV42-85, PV42-129, PV42-142, PV42-143, ST12-31, ST42-08, PV03-44, FHIA-03 e SH 3640) e quatro cultivares (Pacovan, Prata Comum, Nam e Figue Pomme Naine), que foram avaliadas quanto ao peso, comprimento, circunferência, relação polpa/casca, resistência ao desprendimento, firmeza, sólidos solúveis totais (SST), acidez total titulável (ATT), relação SST/ATT e tempo de amadurecimento. Empregou-se um delineamento inteiramente casualizado, com cinco repetições para todas as características, exceto para a firmeza do fruto em que se utilizaram dez repetições. A unidade experimental foi constituída de um único fruto. Os dados foram submetidos à analise de variância e as médias comparadas pelo Teste Scott & Knott, a 5% de probabilidade. A cultivar Nam apresentou a menor acidez titulável e a maior relação SST/ATT, enquanto a maior firmeza do fruto foi apresentada pelos híbridos PV42-81 e PV42-53. Os frutos mais pesados foram do híbrido SH 3640, e os mais compridos foram dos híbridos Bucaneiro e PV42-81. Os híbridos PV42-85 e ST42-08 apresentaram maior resistência ao desprendimento, não diferindo da 'Pacovan'. No entanto, superaram a 'Prata Comum', que obteve a menor resistência. Os genótipos 'Nam', PV42-143 e PV42-129 apresentaram maior tempo de maturação após a colheita quando comparados, principalmente, à 'Prata Comum'. A 'Nam' deve ser considerada como uma nova alternativa na produção de banana. O SH3640, híbrido da Prata Anã, pode ser recomendado como nova cultivar. Os híbridos da Prata São Tomé (ST42-08) e Pacovan (PV42-85, PV42-81, PV42-68, PV42-53, PV42-129 e PV42-143) podem substituir as cultivares Prata Comum e Pacovan nos sitemas produção.The knowledge of the post-harvest characteristics of new banana hybrids is an important information that helps the breeder in making his decision. This work has the objective to evaluate banana genotypes in relation to their post-harvest characteristics and resistance to fruit drop. Fruits of the second hand of 16 hybrids (Calipso, Bucaneiro, Ambrosia, YB42-21, PV42-53, PV42-68, PV42-81, PV42-85, PV42-129, PV42-142, PV42-143, ST12-31, ST42-08, PV03-44, FHIA-03 and SH 3640) and four cultivars (Pacovan, Prata Comum, Nam and Figue Pomme Naine) were evaluated according to their weight, length, circumference, pulp/peel ratio, resistance to fruit drop, firmness, total soluble solids (TSS), total titratable acidity (TTA), TSS/TTA ratio and maturation period. A completely randomized experimental design was used, with five replications, except fruit firmness with ten replications, each unit was constituted by one fruit. The data were submitted to the analysis of variance and the means were compared by the Scott & Knott test at 5% of probability. The cultivar Nam had the lowest TTA and the highest TSS/TTA ratio, while the highest fruit firmness was observed in PV42-81 and PV42-53. The SH 3640 produced the heaviest fruits, and Bucaneiro and PV42-81 produced the longest ones. PV42-85 and ST42-08 showed high resistance to fruit drop, with no statistical difference from 'Pacovan'. 'Prata Comum' showed the lowest resistance. The genotypes ' Nam', PV42-143 and PV42-129 showed longer shelf life when compared to 'Prata Comum'. 'Nam' genotype can be considered as alternative in banana production. SH3640 the Prata dwarf hybrid, might be considered as a new cultivar. Hybrids from Prata São Tomé (ST42-08) and from Pacovan (PV42-68, PV42-81, PV42-85, PV42-129 e PV42-143) can replace Prata Comum and Pacovan in the banana production system.

Introduction: The Pacific abalone, Haliotis discus hannai, is one of the most commercially important marine shellfish in China. Cell engineering breeding is an important tool in abalone genetic breeding, and the triploids obtained through this method have high commercial value. However, current research mainly focuses on establishing induction methods and evaluating the growth traits of triploids, while there is a lack of basic research on triploid cytogenetics., Method: In this study, Cytogenetic analysis of triploid Haliotis discus hannai larvae (produced by chemical treatment) and diploid larvae was performed., Result: The results showed that triploid H. discus hannai had a chromosome number of 3n = 54, consisting of 30 metacentric (m) and 24 submetacentric (sm) chromosomes, while the diploids had a chromosome number of 2n = 36, consisting of 20 metacentric (m) and 16 submetacentric (sm) chromosomes. Notably, both triploids and diploids displayed variation in the number of NORs and/or their diameter. The average number of NORs in triploid was significantly higher than that in diploids (p &lt; 0.05), but the average diameter of NORs of triploid was no significant different from that of diploid (p &gt; 0.05). Additionally, 5S rDNA localization to 3 submetacentric chromosomes was observed in triploids, compared to 2 submetacentric chromosomes in diploids. The number of 18S rDNA sites displayed positional conservancy and quantitative variability in both diploids and triploids. Specifically, 18S rDNA was found at the end of the chromosome in both groups, with triploids exhibiting a significantly higher number of loci than diploids (p &lt; 0.01)., Conclusion: This study provides valuable insights into the cytogenetic characteristics of triploid H. discus hannai, which could facilitate further research on the stability of the chromosome set in this species., (© 2023 S. Karger AG, Basel.)

Lilium lancifolium , the tiger lily, constitutes a polyploid complex with both diploids (reproduced by seeds and bulbils) and triploids (propagated exclusively via bulbils). An autopolyploid origin for the triploid forms has been previously suggested based on classical cytogenetics, chromosome mapping techniques, ecological data, and geographic distribution in their native range (Korea and the Japanese Tsushima Island). Using 13 allozyme loci, we comparatively assessed clonal structure and levels of genetic diversity in four diploid and 11 triploid populations in South Korea to test the autopolyploid origin of the triploid cytotype and to infer which seedling recruitment strategy is operating within the diploid populations. We also employed ecological niche modeling and multivariate analysis to determine whether triploids of L. lancifolium occupy different and broader niches to those of diploids in Korea and Tsushima Island. The diploids harbored higher levels of within-population genetic diversity than triploids, and allele profiles found in triploids were exactly subsets of those in diploids. Repeated seedling recruitment was inferred for the diploids, whereas all the studied triploid populations were monoclonal since there is no seedling (sexual) recruitment. Although we found no niche divergence between cytotypes of L. lancifolium , the triploids have a broader niche breadth. Genetic data further confirm the autotriploid origin of L. lancifolium , and the lack of a clear, strong evidence for niche divergence between cytotypes of L. lancifolium supports the view that ecological differentiation is not a pre-requisite for the establishment of new polyploid lineages. [ABSTRACT FROM AUTHOR]

Palearctic green toads ( Bufo viridis subgroup) represent one of the few vertebrate systems with three bisexually reproducing ploidy levels that can form population systems where up to three ploidy levels interact reproductively. However, especially from Western Central Asia, very few cytogenetic data are available. Therefore, we investigated the cytogenetic status and ploidy of 15 populations of the Bufo viridis subgroup, represented by diploid (2 n ) B. variabilis, 2 n B. turanensis , as well as tetraploid (4 n ) B. oblongus in Iran. Karyotypes of 70 individual toads revealed three ploidy levels. While diploids (2 n = 22) were found at 10 localities mostly from Northeastern (Kopet–Dagh range) and a population of 2 n B. variabilis from Western Iran, tetraploid (4 n = 44) B. oblongus were detected in four populations from Central and Eastern Central Iran. For the first time, we report triploid green toads (3 n = 33) from Iran that were detected at two localities at the Eastern slopes of the Kopet–Dagh range (Yekkeh Bid, and Bazangan). These triploids probably do not appear to result from primary diploid–tetraploid hybridizations. Instead, co-occurrence of triploids with diploids may indicate a population system, in which both (2 n and 3 n ) interact reproductively. These findings, which we compare with knowledge from other diploid–triploid vertebrate reproductive systems, deserve further investigations and raise evolutionary questions regarding origin and interaction of green toads of different ploidy levels in Iran. [ABSTRACT FROM AUTHOR]

Mulberry (Morus sp.) is one of the economically important trees grown in Asian countries. It is cultivated to provide leaves for feeding the caterpillars of the silk producing insect (Bombyx mori L.). In addition, it adds value through production of edible fruits, timber and several pharmaceutically important chemicals. Improvement of mulberry through conventional breeding is limited due to high heterozygosity and long generation period. Attempts have recently been made to complement conventional breeding with modern biotechnological tools such as plant tissue culture, recombinant DNA technology and molecular markers to facilitate mulberry genetic improvement. The techniques of tissue culture have grown considerably in mulberry and encompassed areas including micropropagation, plant regeneration from leaf discs, and screening for stress tolerance. Recently, genetic engineering was adopted to enhance drought and salt tolerance in mulberry using HVA1 and Osmotin genes. Molecular markers such as Random amplified polymorphic DNA (RAPD), inter simple sequence repeats (ISSR) and simple sequence repeats (SSR) have been used for molecular characterization of mulberry germplasm, biodiversity analysis, genetic mapping and identification of molecular markers for growth and yield . However, still a number of issues such as resistance to fungal and bacterial diseases, combating infestation of pests and insects, and tolerance to drought and salinity are to be sorted out to achieve sustainable mulberry cultivation to meet the increasing demand of the silk industry. This review describes the developments of tissue culture, transgenesis and molecular markers in mulberry and highlights the current constraints and future prospects. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine and compare for the first time the size of eggs laid by C. taenia (2n=48) and its naturally occurring triploid (3n=74) hybrid females and the total length of offspring of these females obtained from experimental crosses, in the period from hatch to 22 days post hatch. The eggs laid by triploid females had an average diameter of 1.18mmand were significantly larger than the eggs spawned by C. taenia females, which averaged 0.93 mm in diameter. The size of the triploid female eggs was associated with their level of ploidy. Similarly, the average total length of triploid female progeny from one to ten days post hatch was statistically significantly higher than the average total length of C. taenia offspring in the same period of life. After two weeks, the offspring of diploid and triploid females reached average total lengths of 13.27 mm and 13.60 mm, respectively, which was not a significant difference. The possible causes of triploid Cobitis female domination in diploid-polyploid populations in terms of egg size and other traits associated with polyploid functioning was also investigated. [ABSTRACT FROM AUTHOR]

Changes in the morphology of gonads under the effect of methyltestosterone in juveniles of triploid rainbow trout Oncorhynchus mykiss incubated and cultivated in a trout farm under climatic conditions of South Vietnam have been studied. It was shown that the effect of the androgenic hormone intensifies the formation and development of testes in triploid rainbow trout at an age of 1+, decreasing the proportion of sterile individuals and the proportion of fish with anatomical and cytological anomalies in the structure of gonads. The relationship between the found anomalies in the structure of the genital system of trout and its triploidization, hormonal effect, and abiotic environmental conditions is discussed. [ABSTRACT FROM AUTHOR]

Although hybridisation is common in animals, it rarely results in speciation. Yet, many examples of hybrid species have been documented in one animal group, the stick insects (Phasmida)., The New Zealand stick insect Acanthoxyla is of particular interest as the entire genus is of hybrid origin and consists of eight morphological forms recognised as species, all of which are obligate parthenogens., Using five complementary techniques on the same individuals, our study confirms that both triploids and diploids are present in Acanthoxyla populations, and further, that some individuals contain both diploid and triploid cells., Chromosome spreads and estimates of relative DNA content from flow cytometry provided contrasting information about the ploidy of this unusual parthenogenetic genus., Analysis of morphometric variation showed no correlation with ploidy level in Acanthoxyla, and also mtDNA sequence networks failed to distinguish morphospecies or ploidy level., Unexpectedly, cloned sequences of a putatively single-copy nuclear marker were also unhelpful in distinguishing ploidy, instead indicating that phosphoglucose isomerase is likely to be a multiple copy gene., We propose a mechanism for the evolution of the Acanthoxyla lineage and suggest that interpretation may be complicated by the presence of individuals that are diploid and triploid mosaics. [ABSTRACT FROM AUTHOR]