Hybrid Clones Research Articles

VERNALIZING PRE-TRANSPLANTS IMPROVED THE AGRONOMIC CHARACTERISTICS OF STRAWBERRY GENOTYPES UNDER TROPICAL CONDITIONS1

ABSTRACT Strawberry plant yields improve if they accumulate a certain number of cold hours, which does not occur naturally under tropical and subtropical climatic conditions. This study evaluated the agronomic characteristics of potted transplants from 14 strawberry genotypes that had been subjected to vernalization treatment prior to planting in the field. The transplants were stored in a cold chamber at 5°C for 576 h. The genotypes used in the experiment were Camino Real, Festival, Florida Eliane, Sweet Charliefp, Sweet Charlie, Dover, IAC Guaraní, Corea, Early Bright, and hybrid clones Dover × Rosalinda1 Dover × Rosalinda4, Dover × Oso Grande, Dover × Esplendida, and Dover × Aichi. The 14 genotypes in the control group received no vernalization treatment. Each experimental unit consisted of 15 plants. A randomized complete blocks experimental design was used with a 14 × 2 factorial arrangement and three repetitions. Subjecting the strawberry transplants to the vernalization treatment had a significant effect on the total number of fruits per plant and total and commercial yield of fruits per plant, but there was no significant interaction between the factors and the evaluated yield and growth characteristics. Dover × Oso Grande, Florida Eliane, Camino Real, and Festival produced the greatest numbers of large fruits per plant. Vernalizing strawberry transplants increased the yield and the number of medium and small sized fruits per plant. The results showed that vernalization is a technique that could be used in tropical climate conditions to improve strawberry cultivation productivity.

Growth, production and wood quality in integrated crop-livestock-forest and monoculture systems

This work aimed to evaluate the growth, production and wood quality a clonal hybrid (Eucalyptus grandis x Eucalyptus urophylla) produced in integrated crop-livestock-forest systems (iCLF) and monoculture. The study was carried out in an iCLF system and a monoculture stand, both in the municipality of Sinop, state of Mato Grosso, Brazil. Diameter (at 1.3 m height), total height and production (volume) of trees were evaluated, along with wood quality (growth strains and wood density). The parameters of the trees in the iCLF system were analyzed according to the different positions of the trees in the plantation (lines and between rows), and were compared with the quality of the wood produced in the traditional system (homogeneous plantation). The results indicated an approximate yield of 22.98 m-3 ha-1 year-1 for iCLF and 32.15 m-3 ha-1 year-1 for traditional planting. The longitudinal residual deformation LRD (growth stress) in the iCLF system was higher for the central trees of the stand. The canopy projection in monoculture plantation and the central line of the iCLF system presented more homogenous distribution in relation to the other planting lines. The trees produced in the integrated system presented greater wood density than those produced in the monoculture.

No evidence for accumulation of deleterious mutations and fitness degradation in clonal fish hybrids: Abandoning sex without regrets.

Despite its inherent costs, sexual reproduction is ubiquitous in nature, and the mechanisms to protect it from a competitive displacement by asexuality remain unclear. Popular mutation‐based explanations, like the Muller's ratchet and the Kondrashov's hatchet, assume that purifying selection may not halt the accumulation of deleterious mutations in the nonrecombining genomes, ultimately leading to their degeneration. However, empirical evidence is scarce and it remains particularly unclear whether mutational degradation proceeds fast enough to ensure the decay of clonal organisms and to prevent them from outcompeting their sexual counterparts. To test this hypothesis, we jointly analysed the exome sequences and the fitness‐related phenotypic traits of the sexually reproducing fish species and their clonal hybrids, whose evolutionary ages ranged from F1 generations to 300 ky. As expected, mutations tended to accumulate in the clonal genomes in a time‐dependent manner. However, contrary to the predictions, we found no trend towards increased nonsynonymity of mutations acquired by clones, nor higher radicality of their amino acid substitutions. Moreover, there was no evidence for fitness degeneration in the old clones compared with that in the younger ones. In summary, although an efficacy of purifying selection may still be reduced in the asexual genomes, our data indicate that its efficiency is not drastically decreased. Even the oldest investigated clone was found to be too young to suffer fitness consequences from a mutation accumulation. This suggests that mechanisms other than mutation accumulation may be needed to explain the competitive advantage of sex in the short term.

Long term performance of certain ortets and hybrid clones of Hevea brasiliensis in a high altitude region in Kerala, India

Long term performance of four hybrid Hevea clones and ten ortet selections including nine from a high elevation site within the traditional rubber growing tract of Kerala was studied. Significant variability was observed among the hybrids and ortets for all major agronomic traits. Growth of rubber trees was invariably poor in the high altitude region and tappability by the tenth year of planting was less than 50 per cent. The hybrid clones RRII 203 and RRIC 100 showed highest growth vigour with 80 per cent tappability by the 13th year of planting. Among the ortets, P 270 and Iritty 1 recorded the highest tappability of 64 per cent. The ortet P 270 was the best performer with the highest girth at the opening (61 cm), girth increment during immaturity (5.5 cm) on tapping (3.4 cm) and bole volume (0.1 m3). RRII 203 was the highest yielding clone with 56 g tree-1 tap-1 over eight years of tapping. High annual yield (48 g tree-1 tap-1) and lean season yield of P 270 combined with high drc on par with the highest yielding clone RRII 203 indicated the specific adaptability of this ortet to high elevation areas. The ortets P 213 and Iritty 1 and hybrid clone RRIC 100 were the other promising clones exhibiting growth adaptation and high yield potential under high altitude conditions.

Assessing wood properties on hybrid poplars using rapid phenotyping tools

There is a growing interest in improving wood properties through clonal selection. However, traditional methods for determining wood properties are difficult to implement at the scale required for large-scale selection programs. In this study, we used rapid phenotyping methods (i.e., drill resistance (DR) and stress wave velocity (SWV)) for assessing wood quality in a 3-year-old clonal trial containing 125 clonal poplar hybrids. These hybrids belong to interspecific crosses of Populus deltoides [D], P. trichocarpa [T], P. nigra [N], and P. maximowiczii [M]. We estimated clonal variation and correlations among DR, SWV, basic density (BD), and dynamic modulus of elasticity (MOEd). Clonal repeatabilities were moderate for all traits, but were higher for BD and DR (i.e., R2 = 0.45 and 0.46, respectively) than for SWV and MOEd (i.e., R2 = 0.30 and 0.35, respectively). Clonal mean phenotypic correlations were high between BD and DR (rc = 0.84) and between SWV and MOEd (0.87), and the clonal correlations (rg) were 0.90 and 0.96, respectively. Overall, there was a weak relation between BD and MOEd (rc = 0.23 and rg = 0.29, respectively). Results support the use of DR and SWV as tools for the selection of poplar clones oriented to improve solid wood properties.

Physical and Mechanical Properties of Fast Growing Polyploid Acacia Hybrids (A. auriculiformis × A. mangium) from Vietnam

Acacia plants are globally important resources in the wood industry, but particularly in Southeast Asian countries. In the present study, we compared the physical and mechanical properties of polyploid Acacia (3x and 4x) clones with those of diploid (2x) clones grown in Vietnam. We randomly selected 29 trees aged 3.8 years from different taxa for investigation. BV10 and BV16 clones represented the diploid controls; X101 and X102 were the triploid clones; and AA-4x, AM-4x, and AH-4x represented neo-tetraploid families of Acacia auriculiformis, Acacia mangium, and their hybrid clones. The following metrics were measured in each plant: stem height levels, basic density, air-dry equilibrium moisture content, modulus of rupture (MOR), modulus of elasticity (MOE), compression strength, and Young’s modulus. We found that the equilibrium moisture content significantly differed among clones, and basic density varied from pith-to-bark and in an axial direction. In addition, the basic density of AA-4x was significantly higher than that of the control clones. Furthermore, the MOR of AM-4x was considerably lower than the control clones, whereas the MOE of X101 was significantly higher than the control values. The compression strength of AM-4x was significantly lower than that of the control clones, but AH-4x had a significantly higher Young’s modulus. Our results suggest that polyploid Acacia hybrids have the potential to be alternative species for providing wood with improved properties to the forestry sector of Vietnam. Furthermore, the significant differences among the clones indicate that opportunities exist for selection and the improvement of wood quality via selective breeding for specific properties.

Cytogenetic Characterization of Seven Novel satDNA Markers in Two Species of Spined Loaches (Cobitis) and Their Clonal Hybrids.

Interspecific hybridization is a powerful evolutionary force. However, the investigation of hybrids requires the application of methodologies that provide efficient and indubitable identification of both parental subgenomes in hybrid individuals. Repetitive DNA, and especially the satellite DNA sequences (satDNA), can rapidly diverge even between closely related species, hence providing a useful tool for cytogenetic investigations of hybrids. Recent progress in whole-genome sequencing (WGS) offers unprecedented possibilities for the development of new tools for species determination, including identification of species-specific satDNA markers. In this study, we focused on spined loaches (Cobitis, Teleostei), a group of fishes with frequent interspecific hybridization. Using the WGS of one species, C. elongatoides, we identified seven satDNA markers, which were mapped by fluorescence in situ hybridization on mitotic and lampbrush chromosomes of C. elongatoides, C. taenia and their triploid hybrids (C. elongatoides × 2C. taenia). Two of these markers were chromosome-specific in both species, one had centromeric localization in multiple chromosomes and four had variable patterns between tested species. Our study provided a novel set of cytogenetic markers for Cobitis species and demonstrated that NGS-based development of satDNA cytogenetic markers may provide a very efficient and easy tool for the investigation of hybrid genomes, cell ploidy, and karyotype evolution.

Comparison of hybrid clones derived from human breast epithelial cells and three different cancer cell lines regarding in vitro cancer stem/ initiating cell properties

BackgroundSeveral physiological (fertilization, placentation, wound healing) and pathophysiological processes (infection with enveloped viruses, cancer) depend on cell fusion. In cancer it was postulated that the fusion of cancer cells with normal cells such as macrophages or stem cells may not only give rise to hybrid cells exhibiting novel properties, such as an increased metastatic capacity and drug resistance, but possibly also cancer stem/ initiating cell properties. Hence, hybrid clone cells (M13HS, M13MDA435 and M13MDA231) that were derived from spontaneous fusion events of human M13SV1-EGFP-Neo breast epithelial cells and HS578T-Hyg, MDA-MB-435-Hyg and MDA-MB-231-Hyg cancer cells were investigated regarding potential in vitro cancer stem/ initiating cell properties.MethodsCD44/CD24 expression pattern and ALDH1 activity of parental cells and hybrid clones was determined by flow cytometry. A colony formation and mammosphere formation assay was applied to determine the cells’ capability to form colonies and mammospheres. Sox9, Slug and Snail expression levels were determined by Western blot analysis.ResultsFlow cytometry revealed that all hybrid clone cells were CD44+/CD24−/low, but differed markedly among each other regarding ALDH1 activity. Likewise, each hybrid clone possessed a unique colony formation and mammosphere capacity as well as unique Snail, Slug and Sox9 expression patterns. Nonetheless, comparison of hybrid clones revealed that M13HS hybrids exhibited more in vitro cancer stem/ initiating cell properties than M13MDA231 and M13MDA435 hybrids, such as more ALDH1 positive cells or an increased capacity to form colonies and mammospheres.ConclusionThe fate whether cancer stem/ initiating cells may originate from cell fusion events likely depends on the specific characteristics of the parental cells.

Composted sewage sludge with sugarcane bagasse as a commercial substrate for Eucalyptus urograndis seedling production

Sewage sludge can be used as a source of organic matter and nutrients, whereas sugarcane bagasse can be used as a decompaction material; by composting a mixture of the two, a low-cost substrate for forest nurseries can be obtained. This research investigated the use of composted sewage sludge with sugarcane bagasse (CSB) as a commercial substrate in nurseries to grow seedlings of the hybrid clone Eucalyptus urograndis. Several CSB treatments were evaluated in comparison with a control (no P addition) and a commercial substrate (CS). Before composting, CSB was conditioned with P to increase its final concentration: CSB+1.5, 3.0, and 4.5% triple superphosphate (TP) or reactive phosphate (RP). After 120 d, the Eucalyptus response to all eight substrates was assessed by: i) plant morphological traits (H, height; D, diameter; SB, shoot biomass; RB, root biomass; TB, total dry biomass; GCI, green color intensity; and root system quality) and ii) chemical parameters of shoots and roots. Significant differences among treatments were ascertained using an ANOVA, and variability was interpreted using principal factor analysis (PFA). The treatment with CSB+3% TP (TP3.0) exhibited statistically (p < 0.05) higher performance in regards to morphological parameters (H, D, SB, TB) and the nutrient contents of shoots and roots (N, P, Ca, Na, Mn, Zn, and Cu) than the other treatments and control. The results suggest that B and K could play a fundamental role in both the observed variability and the improved plant performance in the TP3.0 substrate. PFA also showed i) the key role of OM as the primary source/sink of some pivotal macronutrients/heavy metals and ii) the existence of important antagonistic/synergistic effects between elements as a primary driver affecting the concentration/behavior of elements in the shoot/root system. Overall, the research demonstrated that with an addition of only 3.0% TP, the CSB performance was better than the most commonly used and widespread commercial substrate in industrial forest nurseries.

Responses of resistant and susceptible hybrid clones of Eucalyptus urophylla × Eucalyptus grandis to infection by Ceratocystis fimbriata

A histopathological study using one resistant and one susceptible clone of Eucalyptus urophylla × Eucalyptus grandis hybrid showed that the colonization of Ceratocystis fimbriata was limited by rapid and intense host defense responses such as closure of the vessel pits; formation of tyloses and gels; accumulation of amorphous material, starch, phenolic compounds, and calcium oxalate; and tissue lignification. The defense mechanisms of the resistant clone were not lethal to the pathogen because the fungus was reisolated from the diseased tissue. The use of resistant genotypes of eucalypt is widely used to control Ceratocystis wilt caused by Ceratocystis fimbriata. However, little is known regarding the fungal infection process and the host defense responses. Thus, the objectives of this study were to compare the histopathological responses of one resistant and one susceptible clone of Eucalyptus urophylla × Eucalyptus grandis to artificial inoculation with C. fimbriata and to identify possible host defense responses against fungal infection. Fungal colonization was analyzed by light and scanning electron microscopy. The host defense responses to artificial fungal inoculation were evaluated through histochemical analysis and determining of the lignin concentration and lesion lengths, whereas the pathogen viability was confirmed by reisolations. Both tested clones showed similar responses against fungal infection but presented defense responses with different speeds and intensities. Fungal colonization was not restricted in the tissue of plants from the susceptible clone, whereas in the resistant clone, fungal colonization was limited to the xylem vessels and parenchyma around the vessels due to closure of the vessel pits; intense formation of tyloses and gels; accumulation of amorphous material, starch, phenolic compounds, and calcium oxalate; and tissue lignification. However, the fungus was reisolated from the inoculated tissues of both clones. The resistance of eucalypt cuttings was found to be based on the rapid and intense defense responses shaped by biochemical and structural mechanisms that contained fungal colonization in the xylem vessels and parenchyma tissues.

H and L Chain Affinity Maturation and/or Fab N-Glycosylation Influence Immunoreactivity toward Neutrophil Extracellular Trap Antigens in Rheumatoid Arthritis Synovial B Cell Clones.

We previously showed that anti-neutrophil extracellular trap (NET) rheumatoid arthritis (RA)-rmAbs derived from CD19+ B cells within RA human synovial tissues frequently react against NETs. In this study, we aimed to characterize the importance of affinity maturation via somatic hypermutation (SHM) within the Ig variable H (VH) and variable L (VL) chains and Fab-N-linked glycosylation in RA synovial B cell clones reactive to NETs and NET-derived Ags such as citrullinated histones. Selected anti-NET RA-rmAbs derived from synovial RA CD19+ B cells were subjected to overlap-PCR to generate germline (GL; VH and VL reverted into GL), hybrid clones (VH/VL region reverted into GL), and N-glycosylation mutants (N→Q) and analyzed for anti-NETs and citrullinated histones (cit-H2B) immunoreactivity. Anti-NET/cit-H2B immunoreactivity of selected RA-rmAbs was abrogated in the VH and VL GL counterpart. In RA B cell hybrid clone RA015/11.88 and RA056/11.23.2, NET and/or cit-H2B immunoreactivity was solely dependent on SHM in the IgVH region whereas RA B cell hybrid clone RA015/11.91 required affinity maturation of both VH and VL for efficient binding to cit-H2B. In 7/80 RA-rmAb, SHM resulted in ex novo N-glycosylation sites in VH and/or VL regions. Removal of Fab-linked glycans in RA056/11.23.2 in the N-mutant counterpart resulted in 90% reduction in immunoreactivity to cit-H2B. Thus, SHM in the IgVH and/or VL regions of RA synovial B cells is necessary for the immunoreactivity to NET-Ags. Fab-N-linked-glycosylation introduction sites are observed in a minority of anti-NET B cell clones but can strongly influence NET-Ag binding.

Transformation of hybrid black poplar with selective and reporter genes affects leaf proteome, yet without indication of a considerable environmental hazard

Poplar is an economically important forest tree used for multiple applications, including bioenergy production. Although genetic engineering allows a quick introduction of desirable traits, simultaneously, it may deliver unintended side effects. Herein, we compared the protein composition in leaves of microclonally propagated fast-growing hybrid clone of Populus deltoides × Populus nigra (Populus × euroamericana), genetically modified with a reporter (GUS) and selective (NPTII) traits, and its non-transgenic parental genotype. By two-dimensional gel electrophoresis, we revealed that 5.5% of 330 detected protein spots were differentially accumulated. The vast majority of them showed lower abundance in the transgenic line. These proteins were mainly involved in primary metabolism, energy production, and protein synthesis/homeostasis; notably, none of them was directly linked to neomycin phosphotransferase or β-glucuronidase activities. Some of the differentially accumulated proteins could be associated with stress response caused by Agrobacterium-mediated transformation. Furthermore, the lower abundance of two cytosolic glutamine synthase isoforms and accumulation of bark storage protein A in the transgenic line, plausibly indicated impaired nitrogen metabolism and storage. The insertion of a model genetic construct did not alter the neighboring genetic loci, and neither toxins nor allergens were differentially abundant. In essence, we detected no protein indicating considerable health or environmental hazard in the transgenic hybrid black poplar.

G\u2009\xd7\u2009E interactions on yield and quality in Coffea arabica: new F1 hybrids outperform American cultivars

Conventional American cultivars of coffee are no longer adapted to global warming. Finding highly productive and stable cultivars in different environments without neglecting quality characteristics has become a priority for breeders. In this study, new Arabica F1 hybrids clones were compared to conventional American varieties in seven contrasting environments, for yield, rust incidence and volume of the canopy. The quality was assessed through size, weight of 100 beans, biochemical analysis (24 aroma precursors and 31 volatiles compounds) and sensory analysis. Conventional varieties were the least productive, producing 50% less than the best hybrid. The AMMI model analysis pointed out five hybrids as the most stable and productive. Two F1 hybrids clones, H1-Centroamericano and H16-Mundo Maya, were superior to the most planted American cultivar in Latin and Central America showing a high yield performance and stability performance. H1-Centroamerica and Starmaya contain more d-limonene than Caturra, while Starmaya contain more 3-methylbutanoic acid than the control. Those two latter volatiles compounds are linked with good cup quality in previous studies. In terms of sensory analysis, Starmaya and H1-Centroamericano scored better than control.

Stocking effects on seasonal tree transpiration and ecosystem water balance in a fast-growing Eucalyptus plantation in Brazil

High stocking short rotation plantations provide high yields for bioenergy use and have been adopted worldwide, especially in tropical areas. This silvicultural approach might alter ecosystem water balances compared with lower stocking, longer rotation practices. The sensitivity of water balance to stocking might also differ among genotypes. We evaluated the primary components of ecosystem water balance (transpiration - Et, canopy interception - Ei, soil evaporation – Es) for two hybrid clones that differ in drought tolerance and productivity (E. urophylla × E. grandis, Clone B2 and E.grandis × E.camaldulensis, Clone C3) planted in stockings ranging from 590 to 2,950 tree ha.-1 in a tropical region in Brazil. On a monthly time step, all water balance components of the two clones were largely related to the seasonality of rainfall, where the wet season represented 73% of the total rainfall, these processes corresponded on average to 76, 75, 67 and 70% of annual canopy interception, soil evaporation, transpiration and evapotranspiration (ET), respectively. For both clones, temperature (R2 = 0.32) and precipitation (R2 > 0.76) explained evapotranspiration responses while adding stocking as a second independent variable slightly improving the model for clone B2 but no improvement was detected for clone C3. When scaling up the monthly data to yearly analyses, all water balance components responded strongly to tree stocking for both clones during the two years of measurements (1.7 to 3.7 years-old). Annual transpiration rose linearly with stocking for the clone B2, rising from 550 mm yr−1 up to 1,039 mm yr−1, corresponding to 53–100% of precipitation (P). The clone C3 showed a much weaker influence of stocking on transpiration, rising only from 550 mm yr−1 at low stocking to 650 mm yr−1 at high stocking (53–63% of P). Canopy interception rose from about 230 mm yr−1 at low stocking to 300 mm yr−1 at high stocking, with little difference between the clones, ranging from 21 to 30% of P. Evaporation from the soil decreased with increased stocking for both clones and represented an average of 20–12% of P from lowest to highest stocking. Total evapotranspiration (ET – sum of Et, Ei and Es) was about 1,000 to 1,050 mm yr−1 at low-to-moderate stockings of both clones, but the less-drought tolerant clone B2 showed substantially higher total evapotranspiration at high stocking (2,900 mm yr−1) compared to the clone C3 (2300 mm yr−1). The difference between precipitation and evapotranspiration (the overall ecosystem water balance) declined with increasing stocking, dropping below 0 at stockings higher than 1,030 tree ha−1 for both clones. High stocking in highly productive Eucalyptus plantations may be less sustainable across multiple rotations, since any deficit in the ecosystem water balance would need to come from longer-term soil water storage. Our results indicate that both genetics and tree stocking can be used as silviculture tools to manage the sustainably of short rotation forest plantations in the face of climate change.

South American species &lt;i&gt;Solanum alandiae&lt;/i&gt; Card. and &lt;i&gt;S. okadae&lt;/i&gt; Hawkes et Hjerting as potential sources of genes for potato late blight resistance

For several decades, wild species of Solanum L. section Petota Dumort. have been involved in potato cultivar breeding for robust resistance to pests and diseases. Potato late blight (LB) is caused by oomycete Phytophthora infestans (Mont.) de Bary, and the genes for race-specific resistance to P. infestans (Rpi genes) have been introgressed into cultivated potatoes by remote crosses and trans- or cisgenesis, first from S. demissum Buk. and, more recently, from other wild species, such as S. bulbocastanum Dun., S. stoloniferum Schlechtd. et Bché, and S. venturii Hawkes et Hjerting (according to the nomenclature by Hawkes, 1990). Most wild species already involved in breeding for LB resistance came from North and Central Americas: series Bulbocastana (Rydb.) Hawkes, Demissa Buk. and Longipedicellata Buk., and some Rpi genes of these species have been already characterized in much detail. Rpi genes of South American species, including the series Tuberosa (Rydb.) Hawkes, have not been sufficiently investigated. Among the latter, this study focuses on the Rpi genes of S. alandiae Card. and S. okadae Hawkes et Hjerting. Four accessions of S. alandiae, one accession of S. okadae and 11 clones of interspecific potato hybrids comprising S. alandiae germplasm from the VIR collection were PCR-screened using specific SCAR (Sequence Characterized Amplified Region) markers for eight Rpi genes. SCAR amplicons of five Rpi genes registered in this study were validated by comparing their sequences with those of prototype genes deposited in the NCBI Genbank. Among the structural homologues of Rpi genes found in S. alandiae and S. okadae, of special interest are homologues of CC-NB-LRR resistance genes with broad specificity towards P. infestans races, in particular R2=Rpi-blb3, R8, R9a, Rpi-vnt1 and Rpi-blb2 (94–99, 94–99, 86–89, 92–98 and 91% identity with the prototype genes, respectively). Our data may help to better understand the process of Rpi gene divergence along with the evolution of tuberbearing Solanum species, particularly in the series Tuberosa.

Optimization of Eucalyptus breeding through random regression models allowing for reaction norms in response to environmental gradients

Reaction norms fitted through random regression models are a powerful tool to identify and quantify the genotype × environment (G × E) interaction and they represent a promising alternative in forest tree breeding for analysis of multi-environment trials. Thus, the objective of this study was to compare random regression models with the compound symmetry model in Eucalyptus breeding for analysis of multi-environment trials. To this end, a data set with 215 Eucalyptus clones of different species and hybrids evaluated in four environments for diameter at breast height and Pilodyn penetration was used. The random regression models provided a better fit for both traits. Results showed that there was genotypic variability among Eucalyptus clones and that the reaction norms over the environmental gradients identified the G × E interaction. The compound symmetry model and the random regression models are highly correlated in terms of genotype ranking for both traits. The main advantage of random regression models over the compound symmetry model is the ability to predict genotypic performance in environments where a genotype has not been evaluated. Thus, our results suggest that reaction norms fitted through random regression models can be successfully used in forest tree breeding for analysis of multi-environment trials.

In Vitro Generation of Leishmania Hybrids

Protozoan parasites in the genus Leishmania produce a broad spectrum of diseases in their human hosts. The strain and species-specific genes controlling these diverse clinical outcomes have remained poorly tractable using reverse genetics approaches. A cryptic sexual cycle involving a meiotic-like process has been described in Leishmania but is so farconfined to parasites growing in the sand fly vector. Here, we describe the reproducible invitro generation of hybrid clones using axenic culture forms of Leishmania tropica promastigotes. Analysis of SNPs marker inheritance and whole-genome sequencing data indicate that the progeny clones are full genomic hybrids. The demonstration that mating-competent forms arise in culture should facilitate experimental study of the mating biology of Leishmania and the generation of large numbers ofrecombinant parasites for positional cloning of important genes.

Effect of growth stress and interlocked grain on splitting of seven different hybrid clones ofEucalyptus grandis×Eucalyptus urophyllawood

AbstractTrees with high levels of growth stress begin to show log end splits (LES) immediately after harvesting, usually reaching its maximum end split in a week, and these tensions also create splits during lumber manufacturing. Interlocked grain is another characteristic that impacts the properties of eucalyptus wood. The aim of this study was to evaluate the effect of growth stress and interlocked grain patterns on log end splitting of seven different hybrid clones ofEucalyptus grandis × Eucalyptus urophyllaplanted in Brazil. The growth stress indicator (GSI) was measured in standing trees before harvesting. Splits were measured on logs in three different stages, and interlocked grain from wood blocks was obtained across the center of the cross-section. The results showed that LES occurred as soon as the trees were harvested; however, for better selection of clones, LES should be evaluated after a week of harvesting. There were statistically significant correlations for GSI with LES. Clones that presented higher values of interlocked grain tended to develop lower values of GSI and LES. Using GSI and interlocked grain measurements, it was possible to select the most indicated eucalyptus clones for lumber production.

Increase in Cell Wall Thickening and Biomass Production by Overexpression of PmCesA2 in Poplar.

Cellulose, the most abundant constituent material of the plant cell walls, is a major structural component of plant biomass. Manipulating cellulose synthesis (CesA) genes by genetic engineering technology, to increase cellulose production may thus offer novel opportunities for plant growth and development. To investigate this, here we produced transgenic “Populus 895 plants” overexpressing the cellulose synthase (CesA2) gene derived from Pinus massoniana under the control of constitutive 35S promoter, via Agrobacterium-mediated transformation. Relative expression levels of PmCesA2 were functionally characterized in poplar hybrid clone “Nanlin895” (Populus deltoides × Populus euramericana). The results demonstrated the transgenic lines showed enhanced growth performance with increased biomass production than did the untransformed controls. It is noteworthy that the overexpression of PmCesA2 in poplar led to an altered cell wall polysaccharide composition, which resulted in the thickening of the secondary cell wall and xylem width under scanning electron microscopy. Consequently, the cellulose and lignin content were increased. Hence, this study suggests that overexpression of PmCesA2 could be used as a potential candidate gene to enhance cellulose synthesis and biomass accumulation in genetically engineered trees.

Protection on Wireless Sensor Network from Clone Attack using the SDN-Enabled Hybrid Clone Node Detection Mechanisms

WSN is an infrastructure less network that consists of mobile nodes that communicate with each other over wireless links. WSN is vulnerable to the node replication attack (clone attack). Attackers through compromising one sensor node replicate many clones having the same identity (ID) from the compromised node, and place these clones in various places of network. Clones contain all the credentials of legitimate member so appears authentic. This makes the conventional cryptographic tools useless and clone detection difficult. Once the node replication attack has been successful it can help the attacker to exploit almost all of the network operations, like routing, data collection, and key distribution, and also to help launch various other attacks such as black hole, wormhole etc. This proposed work therefore attempts a SDN based mechanism that implements a network level route analysis and time-based analysis methods which involves a low cost timely monitoring of the environment to identify and avoid redundant nodes which may be caused due to cloning attack. Thus, the SDN based cyber security applications are most useful in this situation. The implementation of this SDN based mechanism in WSN helps in maintaining and improving the QoS (Quality of service) constraints. The hybrid clone node detection (HCND) mechanism helps to detect the clone node present in the wireless network. This is to perform efficient clone detection in such a way to eliminate cloning attack in proactive fashion. To detect clones locally as well as across geographical region through cost effective identity verification procedure. This method helps to protect the wireless sensor network from the node identity replicas using the superimposed SDIS junction code. The node identity replicas help to choose the credible path for successful transmissions. The superimposed method is to be used for retrieval of information from node participating on the network. To thwart cluster of attacks hosted from the clones, by removing the hosting clones. The simulation result shows that there is the performance analysis of various parameters such as false positive, false negative ratio analysis, precision analysis, recall analysis and detection analysis.