Intergeneric Hybrids Research Articles

Дослідження та розробка методів отримання міжродових гібридів лососевих (Salmonidae (Jarocki or Schinz, 1822)) риб з метою досягнення ефекту гетерозису та підвищення їх рибопродуктивності

Purpose. To study the possibility of obtaining highly productive intergeneric salmonid hybrids between rainbow trout and brook trout; brown trout and brook trout; rainbow trout and brown trout, as well as to develop methodological approaches and determine of optimal variants of hybrid crosses. Findings. In order to obtain intergeneric hybrids, we used six variants of hybrid crosses with brood fish of three salmonids belonging to three families (Salmo, Oncorhynhus, Salvelinus). The study used age-4 female rainbow trout with average body weight of 3296.8 g, Fork length was 62.6 cm, and the average working fecundity was 7420 eggs. Age-3 rainbow trout males had an average body weight of 1613 g and an average body length of 49.8 cm; age-3 brown trout females had an average body weight of 453.8 g and average working fecundity of 1540 eggs, and males had an average weight of 458.7 g; age-3 brook trout females had an average weight of 809.7 g and a length of 38.9 cm with working fecundity of 1732 eggs, and age-4 males had an average weight of 1212.8 g and an average body length of 46.0 cm. Twelve variants of fertilization were used: six variants at normal water temperature and six variants after a temperature shock. Under natural conditions, the creation of intergeneric hybrids is almost impossible, except for variants between brown trout and brook trout, which is due to the similarity of their biology. However, the efficiency of this cross is low and economically impractical for fish farmers. When applying the temperature shock during fertilization, hybrids proved to be the most effective, where females were rainbow trout, and males were brook trout and brown trout. The average weight of young-of-the-year intergeneric hybrids was, depending on the species of fish, from 8 to 54 g. The highest results were obtained for the creation of hybrids where following broodstock was used: ♂brook trout Х ♀brown trout; ♂brown trout Х ♀rainbow trout. In these variants of crossbreeding, the survival rate of young-of-the-year during the period of cultivation was 94.8 and 92.8%, respectively. In particular, the above hybrids did not suffer from infectious diseases during the growing period. Originality. New data on the development of methods for obtaining viable offspring of newly created hybrids were obtained, and the optimal variants of crossing between females and males of these salmonids were determined. Practical value. The results can be used for artificial breeding of salmonids in specialized farms that will allow obtaining high quality products and reducing their costs. Key words:rainbow trout, brown trout, brook trout, incubation, free embryos, larvae, fry, young-of-the-year.

Interactions between mitochondrial and nuclear genomes and co-regulation of mitochondrial and nuclear gene expression in reciprocal intergeneric hybrids between Carassius auratus red var. × Cyprinus carpio L.

Genetic interactions between nuclear and mitochondrial genomes always play an important role in growth and development. However, it is not feasible to directly perform these studies in some animals. The reciprocal hybrid fishes obtained from intergeneric hybridization are an effective research model for the same nuclear genome and different mitochondrial genomes. The transcriptomes of embryonic development (Blastula Period, Gastrula Period, Segmentation Period and Hatching Period) were obtained from the two reciprocal hybrids of Carassius auratus red var. (RCC) ​× ​Cyprinus carpio L. (CC) and their parents. Most of the reads (average ​> ​99.90%) in the transcriptome of F1-RC (C. auratus red var. (♀) ​× ​C. carpio L. (♂)) and F1-CR (C. carpio L. (♀) ​× ​C. auratus red var. (♂)) were optimally mapped to the maternal mitochondrial genome (MMG), respectively. Then, the other reads with optimally mapped to paternal mitochondrial genome exhibited that the partial coverages and low-level (<0.4%) expressions of paternal mitochondrial genes were in the four developmental stages of them, especially hatching period, in which paternal mitochondrial DNA (mtDNA) is always eliminated in animals. In the four stages, some changes of 13 mitochondrial gene expressions were occurred in comparisons of the female parents and their hybrid progenies (F1-RC vs. RCC and F1-CR vs. CC), although no significantly differential expression (DE) was detected in them. Moreover, in each embryonic development stages, the positive correlation between the number of differential expression of nuclear-encoded mitochondrial genes and the p-value of differential expression of mitochondrial genes help us understanding how the detail of mitochondrial-nuclear genetic interactions operate in hybrids. The detection of paternal mitochondrial genome fragments in hatching period provides us insight into potential escape mechanisms which may disrupt or inactivate PME in hybrids. These differential expression of nuclear-encoded mitochondrial genes between reciprocal hybrids may help us understanding of the genetic basis of growth in hybrids and used in their breeding project.

Genome-wide unbalanced expression bias and expression level dominance toward Brassica oleracea in artificially synthesized intergeneric hybrids of Raphanobrassica

Raphanobrassica (RrRrCrCr, 2n = 4x = 36), which is generated by distant hybridization between the maternal parent Raphanus sativus (RsRs, 2n = 2x = 18) and the paternal parent Brassica oleracea (C°C°, 2n = 2x = 18), displays intermediate silique phenotypes compared to diploid progenitors. However, the hybrid shares much more similarities in silique phenotypes with those of B. oleracea than those of R. sativus. Strikingly, the silique of Raphanobrassica is obviously split into two parts. To investigate the gene expression patterns behind these phenomena, transcriptome analysis was performed on the upper, middle, and lower sections of pods (RCsiu, RCsim, and RCsil), seeds in the upper and lower sections of siliques (RCseu and RCsel) from Raphanobrassica, whole pods (Rsi and Csi) and all seeds in the siliques (Rse and Cse) from R. sativus and B. oleracea. Transcriptome shock was observed in all five aforementioned tissues of Raphanobrassica. Genome-wide unbalanced biased expression and expression level dominance were also discovered, and both of them were toward B. oleracea in Raphanobrassica, which is consistent with the observed phenotypes. The present results reveal the global gene expression patterns of different sections of siliques of Raphanobrassica, pods, and seeds of B. oleracea and R. sativus, unraveling the tight correlation between global gene expression patterns and phenotypes of the hybrid and its parents.

Tissue-specific distribution of primary and secondary metabolites of Baemoochae (×Brassicoraphanus) and its changes as a function of developmental stages

The distribution and changes in the primary and secondary metabolite profiles of Baemoochae, an inter-generic hybrid of Chinese cabbage and radish, during the plant’s developmental stages were investigated. Metabolites were analyzed using gas chromatography-mass spectrometry (GC-MS) and ultra-high-performance liquid chromatography-electrospray ionization-quadrupole time-of-flight (UHPLC-ESI-qTOF MS). Free sugar, organic acid, and amino acid composition depended on the tissue type and developmental stage of Baemoochae. For example, glucose and alanine levels were higher in mature leaves than in young leaves; citric acid content in mature roots was lower than that in young roots. Several glucosinolates were identified for the first time in Baemoochae. Glucoraphasatin was predominant in both leaves and roots, regardless of plant maturity. Total glucosinolate content was significantly higher in roots than in leaves and in mature than in young plants. The roots of mature Baemoochae could be used as a rich source of glucosinolates, with several potential health-promoting effects.

Identification of Parental Genome Construction and Inherited Morphological Characteristics in Triploid and AneuploidIntergeneric Hybrids from a Diploid−Diploid Cross between Citrus and Fortunella

We previously obtained two intergeneric hybrids with different ploidies, i.e., aneuploid (2n = 28) and eutriploid, from diploid−diploid crosses between ‘Kiyomi’ tangor (Citrus unshiu Marcow. × C. sinensis (L.) Osbeck) and Meiwa kumquat (Fortunella crassifolia Swingle) as novel breeding materials for a seedless kumquat. In this study, we attempted to clarify the construction of the parental genomes of these hybrids by SSR genotyping and genomic in situ hybridization (GISH)−chromomycin A3 (CMA) analysis. SSR genotyping in NSX43 (LG5) and CiBE2227 (LG8) loci revealed that both hybrids inherited one allele from ‘Kiyomi’ tangor and two heterozygous alleles from Meiwa kumquat. The GISH analysis failed due to the high genomic homology between Citrus and Fortunella. At the same time, the CMA karyotype compositions of the two intergeneric hybrids (H15-701: 2A + 1B + 3C + 13D + 7E + 1F + 1Dst; H15-702: 3A + 1B + 2C + 15D + 4E +1F + 1Dst) and both parents (‘Kiyomi’ tangor: 1A + 2B + 2C + 6D + 7E; Meiwa kumquat: 2A + 2C + 12D + 1F + 1Dst) were completely revealed. We identified the parental genome construction and polyploidization processes in both intergeneric hybrids on the basis of these SSR genotypes and CMA karyotype compositions according to the following theory: the SSR genotypes and chromosome compositions were the same as those of the somatic chromosome and two-fold after the first division (even number) in unreduced gametes caused by first-division restitution (FDR) and second-division restitution (SDR), respectively. Consequently, we determined that both intergeneric hybrids may have had two genomes derived from the 2n male unreduced gamete as a result of the FDR of the Meiwa kumquat. In addition, most horticultural traits of the leaves, flowers, and fruits of both hybrids showed intermediate traits of the parents, but the fruit sizes and flowering habits were more like those of the two inherited genomes of Meiwa kumquat.

Genomic Selection in Sugarcane: Current Status and Future Prospects.

Sugarcane is a C4 and agro-industry-based crop with a high potential for biomass production. It serves as raw material for the production of sugar, ethanol, and electricity. Modern sugarcane varieties are derived from the interspecific and intergeneric hybridization between Saccharum officinarum, Saccharum spontaneum, and other wild relatives. Sugarcane breeding programmes are broadly categorized into germplasm collection and characterization, pre-breeding and genetic base-broadening, and varietal development programmes. The varietal identification through the classic breeding programme requires a minimum of 12–14 years. The precise phenotyping in sugarcane is extremely tedious due to the high propensity of lodging and suckering owing to the influence of environmental factors and crop management practices. This kind of phenotyping requires data from both plant crop and ratoon experiments conducted over locations and seasons. In this review, we explored the feasibility of genomic selection schemes for various breeding programmes in sugarcane. The genetic diversity analysis using genome-wide markers helps in the formation of core set germplasm representing the total genomic diversity present in the Saccharum gene bank. The genome-wide association studies and genomic prediction in the Saccharum gene bank are helpful to identify the complete genomic resources for cane yield, commercial cane sugar, tolerances to biotic and abiotic stresses, and other agronomic traits. The implementation of genomic selection in pre-breeding, genetic base-broadening programmes assist in precise introgression of specific genes and recurrent selection schemes enhance the higher frequency of favorable alleles in the population with a considerable reduction in breeding cycles and population size. The integration of environmental covariates and genomic prediction in multi-environment trials assists in the prediction of varietal performance for different agro-climatic zones. This review also directed its focus on enhancing the genetic gain over time, cost, and resource allocation at various stages of breeding programmes.

Ploidy, genetic diversity and speciation of the genus Aronia

Speciation in Aronia is complex based on Amplified Fragment Length Polymorphism (AFLP) and ploidy analysis of 132, mostly wild, accessions. There are four species of Aronia and seven taxonomic groups comprised of species by ploidy combinations. A. melanocarpa can be diploid or tetraploid, with diploid forms occurring in New England and tetraploid forms occurring primarily outside of New England. A. arbutifolia was only found as a tetraploid and did not appear to occur throughout parts of New England as is generally accepted. It is likely that numerous misidentifications of A. arbutifolia have occurred historically. Almost all wild A. prunifolia were tetraploid, with the exception of a single triploid plant. Evidence from AFLP analysis and several accessions expressing a continuum of morphological characteristics between those of A. arbutifolia and A. melanocarpa suggest that A. prunifolia is of interspecific hybrid origin. The occurrence of a natural triploid A. prunifolia accession and our ability to easily create triploid A. prunifolia progeny from diploid A. melanocarpa by tetraploid A. arbutifolia crosses supports the hybrid formation of the A. prunifolia species. Hybrid A. prunifolia origin is also supported by the prevalence of A. prunifolia accessions in geographic areas where A. arbutifolia and diploid A. melanocarpa interface. Most likely, tetraploid A. prunifolia found in the wild result from repeated formation of triploid F1 interspecific hybrids and the triploid bridge mechanism. AFLP analysis, along with morphology and phenology, suggest that a new species of black-fruited Aronia (melanocarpaS) exists in the southern part of the A. melanocarpa geographic range. A. melanocarpaS plants are placed on a separate branch of the AFLP dendrogram that is separate from other Aronia species. Several accessions with large, wide leaves, large fruits and non-rhizomatous growth were found to be A. mitschurinii, an intergeneric hybrid between Aronia and Sorbus. All A. mitschurinii accessions were tetraploid.

Introduction of the species of the genera Cotoneaster Medik. and × Sorbocotoneaster pozdnjakovii Pojark. from the Siberian flora to the Botanical Garden acad. A. V. Fomin of Taras Shevchenko National University of Kiev (message 3 – × Sorbocotoneaster pozd

A spontaneous intergeneric hybrid of Sorbus and Cotoneaster – Pozdnyakov’s sorbocotoneaster (× Sorbocotoneaster pozdnjakovii Pojark.) is an endemic of the South Yakutia. It is known from the river basin Aldan in the areafrom the city of Tommot to the mouth of the river Uchura and on the Aldan-Amga interfluve. It grows in the undergrowthof sparse pine and larch forests on stony-gravelly limestone slopes. It was first found by L. K. Pozdnyakov, a forester,an employee of the Institute of Forest of the Siberian Branch of the USSR Academy of Sciences, on September 9, 1950,when examining forests on permafrost in Yakutia: “in the area of the confluence of the Aya-Sullalah river into Aldan,105–110 km down the Aldan from Tommot” (from the letter of L. K. Pozdnyakov to A. T. Grevtsova, 1982). The article provides data on the origin of the specimens × Sorbocotoneasters, the morphological description of leaves, flowers, fruits,the peculiarities of growth and development in conditions of Kiev, micrographs of pollen grains, micrographs of theendocarp of fruits of three forms, the beginning of the destruction of the scutellum and hypostyle from the ventral side ina hybrid of the third form. Botanical Garden named after acad. A. V. Fomin of the Taras Shevchenko National Universityof Kiev is the only ex situ conservation site in Eastern Europe of the unique Yakut hybrid × Sorbocotoneaster pozdnjakoviiwith leaves of the 1st, 2nd and 3rd forms.

Identification of Parental Genome Construction and Inherited Morphological Characteristics in Triploid and Aneuploid Intergeneric Hybrids from a Diploid−Diploid Cross between Citrus and Fortunella

Identification of Parental Genome Construction and Inherited Morphological Characteristics in Triploid and Aneuploid Intergeneric Hybrids from a Diploid−Diploid Cross between Citrus and Fortunella

Production and identification of ×Brassicoraphanus distant hybrids between radish (Raphanus sativus L.) and kohlrabi (Brassica oleracea L. var. Caulorapa DC.)

ABSTRACT A fertility obstacle exists in hybrid production between distant related species, particularly from different genera. In the present study, by using tissue culture and chromosome doubling technology, radish (Raphanus sativus L.) and kohlrabi (Brassica oleracea L. var. caulorapa DC.) were subjected to intergeneric distant hybridisation. Through a combination of bud pollination and ovary rescue technology, five putative hybrids were obtained, and three of which were identified as true hybrids with the hybrid acquisition frequency of 0.85%. After tissue culture propagation and colchicine doubling treatment, ×Brassicoraphanus allotetraploids were obtained. Chromosome counting confirmed one plant as allotetraploid with a chromosome doubling rate of 2.70% and 14 seedlings with partial chromosome doubling at a chimaeral rate of 37.8%. The allotetraploid hybrid exhibited normal morphological characteristics, fertile pollen, fuller flower buds and developed pods, compared with the primary hybrid plants. In the present study, the distant hybrid plant that combines the R and C genomes was created to provide basic materials for producing new radish germplasm and to act as a useful bridge for gene transfer between the vegetable species of Brassica and Raphanus.

Applying Biotechnology in the Propagation and Further Selection of Vaccinium uliginosum × (V. corymbosum × V. angustifolium) Hybrids.

The most serious problem of intergeneric and interspecific hybridization is related to overcoming the reproductive isolation of different species. We assessed the efficiency of reproduction under in vitro conditions and the ex vitro growth capacity of interspecific hybrids of Vaccinium uliginosum × (V. corymbosum × V. angustifolium). The percentage of seed germination in in vitro culture was 88% for V. uliginosum, form No. 8 × (V. corymbosum × V. angustifolium), SC5-8, while it was 42% for V. uliginosum, form No. 8 × (V. corymbosum × V. angustifolium), ‘Northcountry’. The analysis of mean value showed that the multiplication rate increased and the shoot height decreased as the 2-isopentenyl adenine (2iP) concentration was increased in the nutrient medium of the studied hybrids. The maximum rate was achieved using 15 μM 2iP. A detailed analysis of the hybrids indicated that the hybrid variant reliably affected growth and development indicators. Inter simple sequence repeat analysis demonstrated that all analyzed hybrids inherited DNA fragments of the parent plants in various combinations, confirming their hybrid nature. Thus, the use of in vitro methods for the propagation and further selection of genotypes is demonstrated as being an effective approach for developing interspecific hybrids of V. uliginosum × (V. corymbosum × V. angustifolium).

MiRNA identification, characterization and integrated network analysis for flavonoid biosynthesis in Brassicacoraphanus

Brassica rapa (AA, 2n = 20) and Raphanus sativus (RR, 2n = 18) are popular vegetables containing multiple secondary metabolites, such as flavonoids and anthocyanins. Nevertheless, few studies on miRNA expression profiles and potential regulatory network of flavonoid metabolism have been reported in the intergeneric hybrid of B. rapa and R. sativus (Brassicacoraphanus, AARR, 2n = 38). Here, the miRNAs of Brassicacoraphanus and its parents were first identified by small RNA sequencing. It was revealed that 315 conserved miRNAs and 193 novel miRNAs were found in Brassicacoraphanus and its parents. Moreover, the miRNA expression profiles were characterized and 204 miRNAs with differential expression were obtained. Further analysis showed that 184 miRNAs were non-additively expressed in Brassicacoraphanus. At last, the potential regulatory network of flavonoid metabolism in Brassicacoraphanus was analyzed by multi-omics data, suggesting possible roles of miR858a and miR157a in regulating flavonoid synthesis pathway in Brassicacoraphanus. Taken together, this study provides useful resources for probing global miRNA expression patterns in Brassicacoraphanus, which facilitates regulatory mechanism research on the biosynthesis pathway of secondary metabolites in Brassicacoraphanus.

Hybridization between wild non‐congeneric parrots may be more common than previously thought

Hybridization in the wild is a relatively common occurrence between species of parrots (Psittaciformes) within the same genus. However, a recent publication documented the successful production of hybrids following mating in the wild between parrot species from different genera, which was the only such case known to the authors. Here, I summarize other cases of apparent successful intergeneric hybridization in wild parrots that have been published in low‐impact regional journals. These cases of intergeneric hybridization in wild parrots have generally occurred when one or both parental species are uncommon, and thus have limited opportunities to mate with conspecifics.

Phenotypic Characterization and RT-qPCR Analysis of Flower Development in F1 Transgenics of Chrysanthemum × grandiflorum.

Gene silencing is the epigenetic regulation of any gene in order to prevent gene expression at the transcription or translation levels. Among various gene silencing techniques, RNA silencing (RNAi) is notable gene regulation technique that involves sequence-specific targeting and RNA degradation. However, the effectiveness of transgene-induced RNAi in F1 generation of chrysanthemum has not been studied yet. In the current study, we used RNAi-constructed CmTFL1 (white-flowered) and CmSVP overexpressed (yellow flowered) transgenic plants of previously conducted two studies for our experiment. Cross hybridization was performed between these intergeneric transgenic and non-transgenic plants of the winter-growing chrysanthemum selection “37” (light pink flowered). The transgene CmSVP was confirmed in F1 hybrids by RT-PCR analysis, whereas hybrids of CmTFL1 parental plants were non-transgenic. Besides this, quantitative real-time PCR (qPCR) was used to explain the molecular mechanism of flower development using reference genes. Intergeneric and interspecific hybrids produced different colored flowers unlike their respective parents. These results suggest that generic traits of CmSVP overexpressed plants can be transferred into F1 generations when crossed with mutant plants. This study will aid in understanding the breeding phenomenon among intergeneric hybrids of chrysanthemum plants at an in vivo level, and such transgenics will also be more suitable for sustainable flower yield under a low-light production system.

Identification of Parental Genome Construction and Inherited Horticultural Traits in Triploid and Aneuploid Intergeneric Hybrids from a Diploid−Diploid Cross between Citrus and Fortunella

Identification of Parental Genome Construction and Inherited Horticultural Traits in Triploid and Aneuploid Intergeneric Hybrids from a Diploid−Diploid Cross between Citrus and Fortunella

Capturing Multiple Disease Resistance in Wheat through Intergeneric Hybridization.

Simple SummaryProviding disease resistance in our crop plants is our ongoing exercise for plant pathologists/breeders/geneticists. Pathogens are continually evolving and releasing new variants. The variants arise through mutations or through sexual cycles on their respective alternate hosts. Thus, the search continues for unique genes for resistance. Another newer concept is the “pyramiding” of resistance genes. It has been shown that a cultivar may last only 3 years or so before being overcome by a new variant of the pathogen. The release of new cultivars with up to four resistance genes will delay their breakdown. In our ongoing work we have also produced pyramids containing a combination of resistance genes, including SrCad for resistance to new races of stem rust, Lr34, which is a major gene for resistance to leaf rust, and Fhb1, which is a common FHB QTL. This required the production of a series of doubled haploids (DH) to produce lines containing all four genes in reasonable-sized populations. A complex series of four-way crosses were required to generate the various gene combinations. In the studies reported here, the essential tools for marker-assisted-selection are produced, i.e., mapping populations containing the resistance genes and molecular makers assigned to each gene. It should be possible to simultaneously manipulate several resistance genes from existing genetic stocks without requiring complex cross combinations. Derivatives from 4 species from the secondary gene pool of wheat—1 diploid (T. monococcum), 2 tetraploid (T. carthlicum; T. timopheevi), and 1 hexaploid (T. miguschovae)—were screened for resistance to Fusarium head blight, leaf rust, stem rust, and stripe rust. Where screening, genetic studies, and mapping were completed it was shown that all species carried resistance to multiple plant diseases. Some derived lines carried resistance to up to four different diseases. Where mapping was completed, it was shown that different diseases mapped to different chromosomes within any one accession.

New intergeneric orchid hybrid found in Romania × Pseudorhiza nieschalkii (Senghas) P.F.Hunt nothosubsp. siculorum H.Kertész & N.Anghelescu, 2020.

We describe the first reported intergeneric, which naturally occurs between two subspecies belonging to different genera, Dactylorhiza fuchsii subsp. sooana (genus Dactylorhiza) and Pseudorchis albida subsp. tricuspis (genus Pseudorchis), as × Pseudorhiza nieschalkii (Senghas) P.F.Hunt nothosubsp. siculorum H.Kertész & N.Anghelescu, 2020. The hybrid was found and digitally photographed for the first time by Hajnalka Kertész in June, 2020, within Terra Siculorum, in one of the Natura 2000 protected areas, known as Harghita Mădăraș, ROSCI00090. Following detailed morphometric analysis using 67 characters and molecular karyological analyses, we identified this unique specimen as an intergeneric hybrid, new to science. The hybrid, an F1 generation plant, most likely representing a single intergeneric pollination event, is phenotypically intermediate between its parental species in most of the characters scored, but it significantly closely resembles Pseudorchis albida subsp. tricuspis parent. Since several individuals of the parental species occurred in near proximity, within 1–10 meters distance, we suggest that the production of this hybrid required a minimum travel distance of ca 1–10 meters, by the pollinators and frequent exchange of pollen between the parental species was very likely. The parental species and the hybrid, which display a considerable synchronicity in their flowering time, overlap in the pollinator community, sharing various species of Hymenopterans and Dipterans, very abundant in the heathland. This Terra Siculorum hybrid is thus best described as a rarely occurring intergeneric hybrid that shows strong Pseudorchis albida subsp. tricuspis parental dominance in inheritance patterns.

Root-based characterization of intergeneric hybrids with Triticum and Aegilops species in early vegetative and stem elongation growth stages

Cultivated and wild species of wheat are valuable breeding resources used for the development of new cultivars with superior root traits suited to drought and non-stressed conditions. The present study aimed to determine genotypes with superior root traits and phenotypic variability among intergeneric hybrids with Triticum and Aegilops species in the early vegetative (Z11) and stem elongation (Z31) growth stages. Results indicated that phenotypic variability in rooting depth was 3.2- and 3.4-fold among the genotypes in Z11 and Z31, and it was as great as 20- and 23.8-fold for root biomass, respectively. Hierarchical clustering among 35 genotypes for root traits in both growth stages identified four major clusters, grouping the six deep-rooted genotypes in cluster 2 and three genotypes with high root biomass in cluster 1. In both growth stages, significant associations were found among the root traits. Also, the relationship was stronger between the root and shoot biomass in Z11 (r2=0.83) than in Z31 (r2=0.44). As an overall assessment, the suggested genotypes with superior root characteristics such as deep roots and/or high root biomass sustained in both growth stages might be used for the development of new cultivars.

Hybridization in Selected Species and Genera of Diaptomid Copepods in China

To better understand the fauna of freshwater calanoid copepods of China, including the occurrence of intra- and intergeneric hybridization, we studied five species, distributed across the whole of China or in South China. We sequenced a mitochondrial (COI) and the nuclear ribosome 18S operon (ITS) to reconstruct the phylogenetic trees by using a Bayesian and maximum likelihood (ML) approach with 161 individuals. The phylogeny tree revealed five clades and two geographically separated subclades in both S. ferus and P. tunguidus. We found, for the first time, that the hybrid specimens occurred in Diaptomidae, but low hybridization suggested effective barriers to hybridization and introgression. One hypothesis, that hybridization is recent and was initiated by invasions via canals built between the Yangtze and Pearl rivers c. 2000 years ago, is not supported by K2P genetic distances of the order of 20%. Furthermore, COI analysis of different populations of S. ferus and P. tunguidus revealed two geographical clades in each species, with genetic distances commensurate with cryptic speciation. Both clades occupy subranges maintained without visible barriers to mixis.

&lt;p&gt;&lt;strong&gt;A natural intergeneric hybrid of Gesneriaceae from Brazil&lt;/strong&gt;&lt;/p&gt;

A natural hybrid between Goyazia and Mandirola (Gloxiniinae, Gesneriaceae) from Cerrado (Brazil) is here described, supported by pollen morphology, cytological data and morphological characters. The microsporogenesis of Mandirola hirsuta and that of the hybrid were analyzed in order to evaluate the cytogenetic characteristics. The haploid chromosome numbers observed were n = 12 for M. hirsuta and n = 11, 13, 16 and 26 for the hybrid. Structural abnormalities (monads, dyads, triads and micronuclei) were observed at the final of the hybrid’s meiosis. High viability rates of the pollen were recorded for Goyazia and Mandirola (&gt;90%) and low viability for the hybrid (34.7%). The pollen grains were acetolyzed, measured and photographed for pollen morphology analysis. Quantitative pollen data were analyzed through descriptive and multivariate statistics. The hybrid has intermediate pollen characteristics between G. petraea and M. hirsuta; it is more related to G. petraea by the measures of diameters and ectoapertures; it is more similar to M. hirsuta mainly regarding the microreticulum on the mesocolpium region. The hybrid and Mandirola share vegetative and flower size, while the colors of the hybrid are similar to Goyazia. Pollen morphology, cytological data and morphological characters brought clear evidence for the recognition of the intergeneric hybrid, which we named as Goydirola x punctata.